NDT Handbook

Non-Destructive TestingInspector’sHandbook

Visual Inspection (VT)

Liquid Penetrant Inspection (PT)

Magnetic Particle Testing (MT)

Ultrasonic Testing (UT)

Eddy Current Testing (ET)

Radiographic Inspection (RT)

Inspector’s Handbook ii

Preface

This reference book was designed for use in the field and to support on-the-job training. It should not be used as a standard or referred to as a stand-alone document. This book covers basic formulas, charts, and other NDT related information.

DedicationTo all the people who have influenced my naval career and where I am today in the Non-Destructive field.

Thank you. I originally started this project as a self-knowledge application and began receiving comments from my fellow colleagues requesting a copy. I soon realized that this would prove to be an invaluable tool for general information in our field. I have received support from both military and civilian personnel and have taken a sample of their suggestions and compiled them for you, the end user. I wanted to take personal credit for this project and realized it would not benefit the NDT field as a whole. Instead, I encourage you, the end user, to change, manipulate, or configure this book for yourself. In closing, “Share the Wealth with Others.”

Last Revision Date02 April 2002

Contact [email protected]

DisclaimerThis book is not intended for sale or any monetary benefit to the editor.

Inspector’s Handbooki

Table of ContentsScope of Standards .............................................................................................................................................. iv

Chapter 1 - General Information ..................................................................... 1 Schedule Designations of Pipe Sizes ................................................................................................................ 1 Copper Tubing Wall Thickness ............................................................................................................... 2 Decimal to Inches ............................................................................................................................................. 2 Temperature Conversions ................................................................................................................................. 2 ..................................................................................................................................................................... 2 Fraction to Decimal Equivalent ........................................................................................................................ 3 Decimal to Second Conversion ........................................................................................................................ 3 Numerical Place Value Chart ........................................................................................................................... 3 Elements of a Nondestructive Examination Symbol ........................................................................................ 4 Elements of a Welding Symbol ........................................................................................................................ 4 Examples of Grooves ........................................................................................................................................ 5 Basic Joints (Welding) ...................................................................................................................................... 5 Order of Performing Arithmetic Operations ..................................................................................................... 6 Ratio And Proportion ........................................................................................................................................ 7 Calculation of Area ........................................................................................................................................... 8 Weld Area Calculation ................................................................................................................................... 8 Common Symbols and Terms ........................................................................................................................ 8 Solution of Right-angled Triangles ................................................................................................................ 10 Basic Illustration of a Weld ........................................................................................................................... 11 Welding Processes .......................................................................................................................................... 12 Backing Ring Common Defect Locations ...................................................................................................... 13 Consumable Insert Common Defect Locations .............................................................................................. 13 Primary Processing Discontinuities ................................................................................................................ 14 Finish Processing Discontinuities ................................................................................................................... 15 Dial Indicating Calipers .................................................................................................................................. 16 Micrometer ..................................................................................................................................................... 16 Thread Terminology (fasteners) ..................................................................................................................... 17 Tap and Drill Size Chart ................................................................................................................................. 17 Julian Date Calendar (Perpetual) .................................................................................................................... 19 Julian Date Calendar (Leap Year) .................................................................................................................. 20 Flow Chart For A Discontinuity ..................................................................................................................... 20

Chapter 2 - Visual Inspection ......................................................................... 1 Common Definitions and Examples ................................................................................................................. 1

Chapter 3 - Liquid Penetrant Testing .............................................................. 1 Common Terms and Definitions ...................................................................................................................... 1 Prorated Maximum Number of Indications ...................................................................................................... 6 Areas of Circles ................................................................................................................................................ 6 Penetrant Wetting Characteristics ..................................................................................................................... 7

Chapter 4 - Magnetic Particle Testing ............................................................ 1 Common Definitions and Examples ................................................................................................................. 1 Longitudinal Magnetization Math Formula ...................................................................................................... 7 Prorated Maximum Number of Indications ...................................................................................................... 8 Areas of Circles ................................................................................................................................................ 8 Common Types of Magnetization .................................................................................................................... 8 ................................................................................................................................................................... 9

Inspector’s Handbook ii

Theory: “Right–Hand Rule” ................................................................................................................. 9 Hysteresis Curve ............................................................................................................................................. 10 Magnetic Particle Field Indicator (Pie Gage) ................................................................................................. 11

Chapter 5 - Ultrasonic Testing ........................................................................ 1 Common Terms and Definitions ...................................................................................................................... 1 Common Math Formulas ................................................................................................................................ 12 Calibration Chart – UT Shearwave ................................................................................................................. 13 FPADSCR λ D ................................................................................................................................................ 14 ....................................................................................................................................................................... 14 Velocity Chart ................................................................................................................................................. 15

Chapter 6 - Eddy Current Testing ................................................................... 1 Common Terms and Definitions ...................................................................................................................... 1 Two Types of Electrical Current ...................................................................................................................... 6 Conductivity and the IACS ............................................................................................................................... 7 Right Hand Rule ............................................................................................................................................... 7 Magnetic Domains ............................................................................................................................................ 9 Depth of Penetration ....................................................................................................................................... 13 Limitations of Eddy Current Testing .............................................................................................................. 20 Advantages of Eddy Current Testing ............................................................................................................. 20 Summary of Properties of Eddy Currents ....................................................................................................... 20 Eddy Current Relationship of Properties ........................................................................................................ 20

Chapter 7 - Radiographic Inspection .............................................................. 1 Common Definitions and Examples ................................................................................................................. 1 Structure of the Atom and an Element ............................................................................................................. 8 Components of an Isotope ................................................................................................................................ 8 Characteristics of A Radioactive Element ........................................................................................................ 8 Two Types of Radiation ................................................................................................................................... 8 History of Radiography .................................................................................................................................... 9 60 ° Coverage for Pipes and Location Marker Measurements ......................................................................... 11 Common Math Formulas ................................................................................................................................ 12 Magic Circles .................................................................................................................................................. 15

A ................................................................................................................. 15 Single Wall Exposure / Single Wall Viewing for Plate .................................................................................. 15 Single Wall Exposure / Single Wall Viewing for Pipe ................................................................................... 16 Double Wall Exposure / Double Wall View (superimposed) ........................................................................ 16 Double Wall Exposure / Double Wall View (offset) ...................................................................................... 17 Double Wall Exposure / Single Wall View .................................................................................................... 17 KILLER CARL .............................................................................................................................................. 18 Penetrameter Material and Group Numbers ................................................................................................... 18 Penny T-Hole Maximum Density ................................................................................................................ 19 2% Penetrameter Quality Conversion Chart (X-RAY ONLY) ...................................................................... 20 Basic Components of an X-ray Tube .............................................................................................................. 25 Types of Scatter Radiation .............................................................................................................................. 25 Radiographic Film Interpretation ................................................................................................................... 26 Probable Causes and Corrective Action for Automatic Film Processing ....................................................... 50 Probable Causes and Corrective Action for Processed Radiographic Film ................................................... 51

Inspector’s Handbookiii

Scope of Standards

NSTP 271 REQUIREMENTS FOR NONDESTRUCTIVE TESTING METHODSThis document covers the requirements for conducting nondestructive tests (NDT) used in determining the

presence of surface and internal discontinuities in metals. It also contains the minimum requirements necessary to qualify nondestructive test and inspection personnel, procedures, and nondestructive equipment. This document does not contain acceptance criteria for nondestructive test. This document does not cover all of the requirements for performing nondestructive tests in an underwater environment. Nondestructive tests in an underwater environment shall be performed as specified in NAVSEA S0600-AA-PRO-070.

NSTP 248 REQUIREMENTS FOR WELDING AND BRAZING PROCEDURE AND PERFORMANCE QUALIFICATION

This document contains the requirements for the qualification of welding and brazing procedures, welders, welding operators, brazers and brazing operators that must be met prior to any production fabrication. It includes manual, semiautomatic, automatic and machine welding and brazing of ferrous, nonferrous, and dissimilar metals. The qualification tests required by this document are devised to demonstrate the adequacy of the welding or brazing procedures and to demonstrate the ability of welders, brazers, welding operators and brazing operators to produce sound welds or brazes.

NSTP 278 REQUIREMENTS FOR FABRICATION WELDING AND INSPECTION, AND CASTING INSPECTION AND REPAIR FOR MACHINERY, PIPING, AND PRESSURE VESSELS

This document contains the welding and allied processes (except brazing) and casting requirements including inspection for the fabrication, alteration, or repair of any item or component of machinery, piping, and pressure vessels in ships of the United States Navy.

MIL-STD 2035 NONDESTRUCTIVE TESTING ACCEPTANCE CRITERIAThe acceptance criteria contained herein are for use in determining the acceptability of nondestructive test

(NDT) discontinuities in castings, welds, forgings, extrusions, cladding, and other products when specified by the applicable Naval Sea Systems Command (NAVSEA) drawing, specification, contract, order, or directive.

NSTP 1688 FABRICATION, WELDING AND INSPECTION SUBMARINE APPLICATIONSThis document contains minimum requirements for fabrication and inspection of submarine and non-

combatant submersible structures, including shipbuilding practices, specifications for materials, weld joint design, workmanship, welding, inspection, and record requirements.

MIL-STD 1689 FABRICATION, WELDING, AND INSPECTION OF SHIPS STRUCTUREThis standard contains the minimum requirements for the fabrication and inspection of the hull and

associated structures of combatant surface ships. The requirements for shipbuilding, materials, welding, welding design, mechanical fasteners, workmanship, inspection, forming, castings and records are included. It also applies to those submarine structures which are not high-yield strength steels.

MIL-STD 22D WELDED JOINT DESIGNThis standard covers welded joint designs for manual, semi-automatic, and automatic arc and gas welding

processes for use on metals and weldments, as applicable, when invoked by a fabrication document. The welded joint designs shown herein represent standard joint designs used in welded fabrication and are not intended to be all inclusive.

Inspector’s Handbook iv

NSTP CHAPTER 074 – VOLUME 1 WELDING AND ALLIED PROCESSESThis chapter furnishes both the minimum mandatory requirements (indicated by the word shall) and

guidance information (indicated by the words should or may) necessary for welding, brazing, inspection, and safety when used for ship maintenance, repair, and alteration.

NSTP CHAPTER 074 – VOLUME 2 NONDESTRUCTIVE TESTING OF METALS QUALIFICATION AND CERTIFICATION REQUIREMENTS FOR NAVAL PERSONNEL (NON-NUCLEAR)

This chapter is furnished to ensure achievement of uniform and reliable nondestructive tests on naval materials and components, implementation of the training, qualification, and certification programs described in this chapter should be followed precisely.

Inspector’s Handbookv

Chapter 1 - General InformationSchedule Designations of Pipe Sizes

SCHEDULE 40 SCHEDULE 80 SCHEDULE 120DIA. O.D. I.D. WALL O.D. I.D. WALL DIA. O.D. I.D. WALL1/8 .405 .269 .068 .405 .215 .095 4 4.500 3.624 .4381/4 .540 .364 .088 .540 .302 .119 5 5.563 4.563 .5003/8 .675 .493 .091 .675 .423 .126 6 6.625 5.501 .5621/2 .840 .622 .109 .840 .546 .147 8 8.625 7.189 .7183/4 1.050 .824 .113 1.050 .742 .154 SCHEDULE 1601 1.315 1.049 .133 1.315 .957 .179 1/2 .840 .466 .187

1-1/4 1.660 1.380 .140 1.660 1.278 .191 3/4 1.050 .614 .2181-1/2 1.900 1.610 .145 1.900 1.500 .200 1 1.315 .815 .250

2 2.375 2.067 .154 2.375 1.939 .218 1-1/4 1.660 1.160 .2502-1/2 2.875 2.469 .203 2.875 2.323 .276 1-1/2 1.900 1.338 .281

3 3.500 3.068 .216 3.500 2.900 .300 2 2.375 1.689 .3433-1/2 4.000 3.548 .226 4.000 3.364 .318 2-1/2 2.875 2.125 .375

4 4.500 4.026 .237 4.500 3.826 .337 3 3.500 2.624 .4384-1/2 5.000 4.506 .247 5.000 4.290 .355 4 4.500 3.438 .531

5 5.563 5.047 .258 5.563 4.813 .375 5 5.563 4.313 .6256 6.625 6.065 .280 6.625 5.761 .432 6 6.625 5.189 .7188 8.625 7.981 .322 8.625 7.625 .500 8 8.625 6.813 ..906

Copper Tubing Wall Thickness

Decimal to InchesDecimal Inches Decimal Inches

0.0833 1 " 0.5833 7 "0.1250 1 1/2 " 0.6250 7 1/2 "0.1667 2 " 0.6667 8 "0.2083 2 1/2 " 0.7083 8 1/2 "0.2500 3 " 0.7500 9 "0.2917 3 1/2 " 0.7917 9 1/2 "0.3333 4 " 0.8333 10 "0.3750 4 1/2 " 0.8750 10 1/2 "0.4167 5 " 0.9167 11 "0.4583 5 1/2 " 0.9583 11 1/2 "0.5000 6 " 1.0000 12 "0.5417 6 1/2 "

inches / 12 = decimaldecimal * 12 = inches

Temperature Conversions

Fahrenheit = (9/5 * C) + 32

Celsius = (F - 32) * 5/9

OD CL - 200 CL - 700 CL - 1650 CL - 3300 CL - 60000.125 - - - - - - - - - - - - - - - 0.028 0.0280.25 0.035 - - - - - - - - - - 0.035 0.0580.375 - - - - - - - - - - - - - - - 0.049 0.0830.405 - - - - - - - - - - - - - - - 0.058 0.0950.5 0.035 0.065 0.035 0.072 0.1200.54 0.065 0.065 0.042 0.072 0.1200.675 0.065 0.072 0.049 0.095 0.1480.75 - - - - - - - - - - 0.058 0.109 0.1650.84 0.065 0.072 0.058 0.120 0.203

1 - - - - - - - - - - 0.072 0.134 0.2201.05 0.065 0.083 0.083 0.148 0.2381.25 - - - - - - - - - - 0.095 0.165 0.2841.315 0.065 0.095 0.095 0.180 0.3001.5 - - - - - - - - - - 0.109 0.203 0.3401.66 0.072 0.095 0.120 0.220 0.3801.9 0.072 0.109 0.134 0.250 0.4252 - - - - - - - - - - 0.148 0.284 0.454

2.375 0.083 0.120 0.165 0.340 0.5202.5 - - - - - - - - - - 0.180 0.340 0.547

2.875 0.083 0.134 0.203 0.380 - - - - -3.5 0.095 0.165 0.250 0.457 - - - - -4 0.095 0.180 0.284 - - - - - - - - - -

4.5 0.109 0.203 0.340 - - - - - - - - - -5 0.120 0.203 0.380 - - - - - - - - - -

Numerical Place Value ChartFor Example 2 , 2 6 2 , 3 5 7 . 6 1 9 8 4 4

2 MILLIONS 1,000,000 D 6 TENTHS 1/10 0.1

2HUNDRED

THOUSANDS100,000 E 1 HUNDREDTHS 1/100 0.01

6TEN

THOUSANDS10,000 C 9 THOUSANDTHS 1/1,000 0.001

2 THOUSANDS 1,000 I 8TEN

THOUSANDTHS1/10,000 0.0001

3 HUNDREDS 100 M 4HUNDRED TEN THOUSANDTHS

1/100,000 0.00001

5 TENS 10 A 4 MILLIONTHS 1/1,000,000 0.000001

7 UNITS 1 L

Fraction to Decimal Equivalent1/ 64 .015625 33/ 64 .5156251/ 32 .03125 17/ 32 .531253/ 64 .046875 35/ 64 .5468751/ 16 .0625 9/ 16 .56255/ 64 .078125 37/ 64 .5781253/ 32 .09375 19/ 32 .593757/ 64 .109375 39/ 64 .6093751/ 8 .125 5/ 8 .6259/ 64 .140625 41/ 64 .6406255/ 32 .15625 21/ 32 .65625

11/ 64 .171875 43/ 64 .6718753/ 16 .1875 11/ 16 .6875

13/ 64 .203125 45/ 64 .7031257/ 32 .21875 23/ 32 .71875

15/ 64 .234375 47/ 64 .7343751/ 4 .250 3/ 4 .750

17/ 64 .265625 49/ 64 .7656259/ 32 .28125 25/ 32 .78125

19/ 64 .296875 51/ 64 .7968755/ 16 .3125 13/ 16 .8125

21/ 64 .328125 53/ 64 .82812511/ 32 .34375 27/ 32 .8437523/ 64 .359375 55/ 64 .8593753/ 8 .375 7/ 8 .875

25/ 64 .390625 57/ 64 .89062513/ 32 .40625 29/ 32 .9062527/ 64 .421875 59/ 64 .9218757/ 16 .4375 15/ 16 .9375

29/ 64 .453125 61/ 64 .95312515/ 32 .46875 31/ 32 .9687531/ 64 .484375 63/ 64 .9843751/ 2 .500 1/ 1 1

Decimal to Second ConversionDECIMAL SECOND DECIMAL SECOND

.017 1 .517 31

.033 2 .533 32

.050 3 .550 33

.067 4 .567 34

.083 5 .583 35

.100 6 .600 36

.117 7 .617 37

.133 8 .633 38

.150 9 .650 39

.167 10 .667 40

.183 11 .683 41

.200 12 .700 42

.217 13 .717 43

.233 14 .733 44

.250 15 .750 45

.267 16 .767 46

.283 17 .783 47

.300 18 .800 48

.317 19 .817 49

.333 20 .833 50

.350 21 .850 51

.367 22 .867 52

.383 23 .883 53

.400 24 .900 54

.417 25 .917 55

.433 26 .933 56

.450 27 .950 57

.467 28 .967 58

.483 29 .983 59

.500 30 1.00 601/60 X SECONDS = DECIMAL (ROUNDED UP TO THE THIRD

PLACE)

Elements of a Nondestructive Examination Symbol

Elements of a Welding Symbol

FINISH SYMBOL

CONTOUR SYMBOLFA LENGTH OF WELD

R PITCH OF WELDS

FIELD WELD

TAIL (N)

GROOVE WELD SIZE

P

AR

RO

W

BO

TH

SID

ES

SID

ES

IDE

DEPTH OF BEVEL; SIZE OR STRENGTH FOR CERTAIN WELDS

GROOVE ANGLE: INCLUDED ANGLE OF COUNTERSINK FOR PLUG WELDS

ROOT OPENING:DEPTH OF FILLING FOR PLUG AND SLOT WELDS

NUMBER OF SPOT, SEAM, STUD, PLUG, OR PROJECTION WELDS

SPECIFICATION OR OTHER REFERENCE (OMITTED WHEN NOT USED)

L-S(E)WELD-ALL-AROUND

ARROW

T OT

HE

R

(N)EXAMINE IN FIELD

TAIL

EXAMINE-ALL-AROUND

REFERENCE LINE

L

NUMBER OF EXAMINATIONS LENGTH OF SECTION TO BE EXAMINED

SPECIFICATION OR OTHER REFERENCE

AR

RO

W

BO

TH

SID

ES

SID

ES

IDE

EXAMINE ALL AROUND FIELD EXAMINATION RADIATION DIRECTION

ARROW

T OT

HE

R

Examples of Grooves

Basic Joints (Welding)

Square Single J Single Bevel

Single Vee Single UDouble Bevel

Butt Lap

Corner

TeeEdge

Order of Performing Arithmetic Operations

When several numbers or quantities in a formula are connected by signs indicating that additions, subtractions, multiplications, or divisions are to be made, the multiplications and divisions should be carried out first, in the order in which they appear, before the additions or subtractions are performed.

Examples: 10 + 26 X 7 - 2 = 10 +182 - 2 = 19018 ÷ 6 + 15 X 3 = 3 + 45 = 4812 + 14 ÷ 2 - 4 = 12 + 7 - 4 = 15

When it is required that certain additions and subtractions should precede multiplication's and divisions, use is made of parentheses () and brackets [].These indicate that the calculation inside the parentheses or brackets should be carried out complete by itself before the remaining calculations are commenced. If one bracket is placed inside of another, the one inside is first calculated.

Examples: (6 - 2) X 5 + 8 = 4 X 5 + 8 = 20 + 8 = 286 X (4 + 7) ÷ 22 = 6 X 11 ÷ 22 = 66 ÷ 22 = 32 + [10 X 6(8 + 2) - 4] X 2 = 2 + [10 X 6 X 10 - 4] X 2

= 2 + [600 - 4] X 2 = 2 + 596 X 2 = 2 + 1192 = 1194

The parentheses are considered as a sign of multiplication; for example, 6(8 + 2) = 6 x (8 + 2).

The line or bar between the numerator and denominator in a fractional expression is to be considered as a division sign. For Example,

12 + 16 + 22 --------------- = (12 + 16 + 22) ÷ 10 = 50 ÷ 10 = 5

10

In formulas the multiplication sign (X) is often left out between symbols or letters, the values of which are to be multiplied. Thus

ABCAB = A X B, and ------ = (A X B X C) ÷ D

D

Ratio And Proportion

The ratio between two quantities is the quotient obtained by dividing the first quantity by the second. For example, the ration between 3 and 12 is 1/4, and the ratio between 12 and 3 is 4. Ratio is generally indicated by the sign (:); thus 12 : 3 indicates the ratio of 12 to 3.

A reciprocal or inverse ratio is the reciprocal or the original ratio. Thus, the inverse ratio 5 : 7 is 7 : 5.

In a compound ratio each term is the product of the corresponding terms in two or more simple ratios. Thus when

8 : 2 = 4, 9 : 3 = 3, 10 : 5 = 2,

then the compound ratio is:

8 X 9 X 10: 2 X 3 X 5 = 4 X 3 X 2,

720 : 30 = 24

Prop is the equality of ratios. Thus,

6 : 3 = 10 : 5, or 6 : 3 :: 10 : 5

The first and last terms in a proportion are called the extremes; the second and thirds, the means. The product of the extremes is equal to the product of the means. Thus,

25 : 2 = 100 : 8 and 25 X 8 = 2 X 100

If third terms in the proportion are known, the remaining term may be found by the following rules:

1) The first term is equal to the product of the second and third terms, divided by the fourth term.

2) The second term is equal to the product of the first and fourth terms, divided by the third.

3) The third term is equal to the product of the first and fourth terms, divided by the second.

4) The fourth term is equal to the product of the second and third terms, divided by the first.

Calculation of Area

Square/Rectangle = Length * Width

Circles = πr 2

Triangle = Height * Base * 1/2

Sphere = 4 2rπ

Weld Area Calculation

Structural Welds = Length * Width (measured)

Piping Welds = Circumference(OD*π ) * Width

Socket Welds = L x W L = ((OD at A + OD at B) / 2) * π W = Width of the weld is measured.

Common Symbols and Terms

π = 3.1415

r = Diameter / 2

ID = Inside Diameter

OD = Outside Diameter

< = Less Than (ie 6<9)

> = Greater Than (ie 9>6)

< = Equal To or Less Than

> = Equal To or Greater Than

+ = Plus or Minus

Sq. Area

L W

A

B

Change percent (%) to decimal (0.0). Move decimal point 2 spaces to the left and drop the percent sign. Example: 2% = 2.0% = .02

Change decimal (0.0) to percent (%). Move decimal point 2 units to the right and add the percent sign. Example: .43 = 43%

Change a fraction to a decimal. Divide the numerator by the denominator. Example: 1/2 = 1 divided by 2 = .5

Tm = Material Thickness, thickness of the thinner member excluding reinforcements.

Ts = Specimen Thickness, thickness of the thinner member including reinforcements.

Minimum Weld Throat Thickness = .7 x TmBased upon 1T X 1T

Solution of Right-angled Triangles

As shown in the illustration, the sides of the right-angled triangle are designated a and b and the hypotenuse, c. The angles opposite each of these sides are designated A and B respectively.

Angle C, opposite the hypotenuse c is the right angle, and is therefore always one of the known quantities.

Sides and Angles Known Formulas for Sides and Angles to be Found

Side a, side b..... c = √ a2 + b2 Tan A = B = 90° - A

Side a, hypotenuse c.. b = √ c2 - a2 Sin A = B = 90° - A

Side b, hypotenuse c.. a = √ c2 - b2 Sin B = A = 90° - B

Hypotenuse c; angle B b = c x sin B a = c x cos B A = 90° - B

Hypotenuse c; angle A b = c x cos A a = c x sin A B = 90° - A

Side b; angle B c = a = b x cot B A = 90° - B

Side b; angle A C = a = b x tan A B = 90° - A

Side a; angle B C = b = a x tan B A = 90° - B

Side a; angle A C = b = a x cot A B = 90° - A

C = 909090°

A

B c

a

b

bSin B

bCos A

aCos B

aSin A

ab

ac

bc

90°

Basic Illustration of a Weld

WELD REINFORCEMENT

ACTUAL THROAT

WELD FACE

THEORETICAL THROAT

TOE

FILLET LEGSIZE OF WELD

FUSION ZONE

ROOT

PENETRATIONZONE

TOE

FUSION

ZONE

FILLET LEGSIZE OF WELD

Tungsten Electrode

Argon or helium shielding gas

Wielding direction

Filler rod

Contact tube

Power source

Shielding gas

Arc

Base metalWeld pool Weld deposit

WIRE GUIDE AND CONTACT TUBE

GAS NOZZLE

GASEOUS SHIELD

CURRENT CONDUCTOR

SHIELDING GAS IN

SOLID ELECTRODE WIRE

WELDING ELECTRODE

ARC

DIRECTION OF WELDING

BASE METAL

WELD METAL

Welding Processes

Shielded Metal Arc Welding (SMAW) An arc welding process, which melts and joins metals by heating them with an arc between a covered metal electrode and the work. Shielding gas is obtained from the electrode outer coating, often called flux. Commonly referred to as “stick” welding.

Gas Metal Arc Welding (GMAW) An arc welding process, which joins metals by heating them with an arc. The arc is between a continuously-fed filler metal (consumable) electrode and the work piece. Shielding gas is supplied from an external source of inert gas, normally argon, helium, or a mixture of the two. Commonly referred to as “MIG” welding.

Flu x Cored Arc Welding (FCAW) An arc welding process which melts and

joins metals by heating them with an arc between a continuous, consumable electrode

wire and the work. Shielding is obtained from a flux contained within the electrode core. Depending upon the type of flux-cored wire, added shielding may or may not be provided from externally supplied gas or gas mixture.

Gas Tungsten

Arc Welding (GTAW)

Normally called TIG

welding (Tungsten Inert Gas), it is a welding process that joins metals by heating them with a tungsten electrode, which should not become part of the completed weld. Filler metal is normally used when welding. Usually helium or argon, or mixture, is used for shielding gas.

SOLIDIFIED SLAG

WELD METAL

WELD POOL

SHIELDING ATMOSPHERE

CORE WIRE

ELECTRODE COVERING

METAL AND SLAG DROPLETS

PENETRATION DEPTH

BASE METALWELD METAL

DIRECTION OF WELDING

BASE METAL

Backing Ring Common Defect Locations

Consumable Insert Common Defect Locations

PIPE WALL

CRACKINGSLAG/OXIDE INCLUSIONSTUNGSTEN INCLUSIONSPOROSITY

OVERLAPUNDERCUT

INCOMPLETE (LACK OF) FUSIONCRACKING

CRACKS INBACKING RINGTACK WELDS

INCOMPLETE (LACK OF) PENETRATIONSLAG OR UNDERCUT AT THE ROOT TOES

CRACKING

BAD FITUPSLAG BETWEEN BACKINGRING AND PIPE ID

MELT-THROUGHBURN-THROUGH

CRACKINGSLAG/OXIDE INCLUSIONSTUNGSTEN INCLUSIONSPOROSITY

OVERLAPUNDERCUT

INCOMPLETE (LACK OF) FUSIONCRACKING

CONCAVITY MELT-THROUGHBURN-THROUGH INCOMPLETE (LACK OF) FUSIONUNDERBEAD CRATERS CENTERLINE CREASEOVERLAP CRACKINGUNDERCUT AT THE ROOT TOESBACKING GAS LOSS/OXIDATION INCOMPLETE (LACK OF) PENETRATION

PIPE WALL

PIPE WALL PIPE WALL

Primary Processing DiscontinuitiesProcess Discontinuity Caused By Location

Casting

Cold ShutLack of fusion between two intercepting surfaces of metal as it flows into the cast

Surface

Hot TearDifference in cooling rates between thin sections and thick sections

Surface

Shrinkage CavityLack of enough molten metal to fill the space created by shrinkage

Subsurface

MicroshrinkageImproperly designed mold causing premature blockage at the mold gate

Subsurface

Blow HolesInability of external gasses to escape from the mold

Surface

Porosity Entrapped internal gassesSurface or Subsurface

Forging

LapFolding of metal in a thin plate on the surface of the forging

Surface

Burst Forging at improper temperatureSurface or Subsurface

Seams

Laminations (flat plate)Flattening and lengthening of discontinuities in parent material

Subsurface

Stringers (bar stock)Flattening and lengthening of discontinuities found in parent material

Subsurface

Seams (bar stock)Lengthening of surface cracks found in parent material

Surface

Welded Pipe

Lack of Fusion Incomplete weldSurface

(inner and outer)

LaminationsPresent in the parent material (sheet or parent material)

Subsurface

Seamless Pipes and

Tubes

Seams Present in the parent material (round bar stock)Outer

Surface

Slugs Metal buildup on piercing materialInner

Surface

Gouges Sizing mandrel draggingInner

Surface

Extrusions

Seams Present in parent material Surface

Porosity Present in parent materialSurface or Subsurface

Galling (cracks) Improper metal flow through the die Surface

Finish Processing DiscontinuitiesProcess Discontinuity Caused By Location

Grinding CracksExcess localized heat created between the grinding wheel and the material

Surface

Heat Treating Stress CracksStress built up by improper processing – unequal heating and cooling

Surface

Explosive Forming

Cracks and Tears Extreme deformation overstresses the material Surface

Welding

Crater Cracks (star, transverse, and longitudinal)

Improper use of heat sourceSurface or Subsurface

Stress CracksStresses built up by the weld contraction (if material is restrained)

Surface

Porosity Entrapped gassesSurface or Subsurface

Slag InclusionsIncomplete cleaning of slag from the weld between passes

Surface or Subsurface

Tungsten Inclusions Excessive current used during GTAW Subsurface

Lack of Penetration Improper welding techniqueSurface or Subsurface

Lack of Fusion Improper welding technique Subsurface

Undercut Improper welding technique Surface

Overlapping Weld overlaps parent material – not fused Surface

Bending Cracks Overstress of material Surface

Machining Tears Working with dull tools or cutting too deep Surface

Pickling or Etching

Cracks Relief of internal stress Surface

Electroplating Cracks Relief of internal stress Surface

Dial Indicating Calipers

1. Verify the caliper’s calibration date is current, and clean all dirt from measuring faces. Perform user calibration on dial indicator, ensure reading is zero, and tighten the bezel clamp as needed.

2. Adjust measuring faces, contact points, to fit item being measured.

3. Apply firm pressure to fine adjusting roll and ensure measuring contacts are in contact with the material being measured.

4. Apply lock screw and read measurement in place if practical. If not, remove calipers carefully to prevent false measurements.

Micrometer

4. Slip the micrometer over the area to be measured by placing the anvil firmly against the material and slowly turn the thimble clockwise until spindle is firmly against the material. Then turn the ratchet three clicks to be sure equal pressure is applied.

5. Take reading in place, or set the locking nut and remove from the item. Determine reading on scale and note accordingly. Do not forget to minus the ball measurement if used.

1. Verify that the micrometer’s calibration date is current, and clean all dirt from measuring contacts.

2. Attach ball if measuring curved surfaces.

3. Adjust micrometer to fit the item being measured, do not spin frame to adjust the micrometer.

FRAME

THIMBLERATCHET

GRADUATIONS

FIXED ANVIL

READING LINE

GRADUATIONS TO BE READ

PART TO BE MEASUREDSPINDLE

LOCK NUT

SLEEVE

Thread Terminology (fasteners)

Tap and Drill Size Chart

THREADSIZE

Coarse ThreadDRILL

DIAMETER

TAP DRILLSIZE

1-64 .0595 No. 53

2-56 .0700 No. 50

3-48 .0785 No. 47

4-40 .0890 No. 43

5-40 .1015 No. 38

6-32 .1065 No. 36

8-32 .1360 No. 29

10-24 .1495 No. 25

12-24 .1770 No. 16

1/4-20 .2010 No. 7

5/16-18 .2570 'F'

3/8-16 .3125 5/16

7/16-14 .3680 'U'

1/2-13 .4219 27/64

9/16-12 .4844 31/64

5/8-11 .5312 17/32

3/4-10 .6562 21/32

7/8-9 .7656 49/64

1"-8 .8750 7/8

THREADSIZE

Fine ThreadDRILL

DIAMETER

TAP DRILLSIZE

0-80 .0469 3/64

1-72 .0595 No. 53

2-64 .0700 No. 50

3-56 .0820 No. 45

4-48 .0935 No. 42

5-44 .1040 No. 37

6-40 .1130 No. 33

8-36 .1360 No. 29

10-32 .1590 No. 21

12-28 .1820 No. 14

1/4-28 .2130 No. 3

5/16-24 .2720 'I'

3/8-24 .3320 'Q'

7/16-20 .3906 25/64

1/2-20 .4531 29/64

9/16-18 .5156 33/64

5/8-18 .5781 37/64

3/4-16 .6875 11/16

7/8-14 .8125 13/16

1"-14 .9375 59/64

AXIS

CRESTHEIGHT OR

DEPTH OF THREADROOT

FLANKS

THREADANGLE

SCREW EXTERNAL THREADSINTERNAL THREADS

MIN

OR

DIA

ME

TE

R

MA

JOR

DIA

ME

TE

R CREST

ROOTPITCH DIAMETER

Julian Date Calendar (Perpetual)

Day Jan Feb Mar Apr May June July Aug Sep Oct Nov Dec Day1 001 032 060 091 121 152 182 213 244 274 305 335 12 002 033 061 092 122 153 183 214 245 275 306 336 23 003 034 062 093 123 154 184 215 246 276 307 337 34 004 035 063 094 124 155 185 216 247 277 308 338 45 005 036 064 095 125 156 186 217 248 278 309 339 56 006 037 065 096 126 157 187 218 249 279 310 340 67 007 038 066 097 127 158 188 219 250 280 311 341 78 008 039 067 098 128 159 189 220 251 281 312 342 89 009 040 068 099 129 160 190 221 252 282 313 343 9

10 010 041 069 100 130 161 191 222 253 283 314 344 1011 011 042 070 101 131 162 192 223 254 284 315 345 1112 012 043 071 102 132 163 193 224 255 285 316 346 1213 013 044 072 103 133 164 194 225 256 286 317 347 1314 014 045 073 104 134 165 195 226 257 287 318 348 1415 015 046 074 105 135 166 196 227 258 288 319 349 1516 016 047 075 106 136 167 197 228 259 289 320 350 1617 017 048 076 107 137 168 198 229 260 290 321 351 1718 018 049 077 108 138 169 199 230 261 291 322 352 1819 019 050 078 109 139 170 200 231 262 292 323 353 1920 020 051 079 110 140 171 201 232 263 293 324 354 2021 021 052 080 111 141 172 202 233 264 294 325 355 2122 022 053 081 112 142 173 203 234 265 295 326 356 2223 023 054 082 113 143 174 204 235 266 296 327 357 2324 024 055 083 114 144 175 205 236 267 297 328 358 2425 025 056 084 115 145 176 206 237 268 298 329 359 2526 026 057 085 116 146 177 207 238 269 299 330 360 2627 027 058 086 117 147 178 208 239 270 300 331 361 2728 028 059 087 118 148 179 209 240 271 301 332 362 2829 029 088 119 149 180 210 241 272 302 333 363 2930 030 089 120 150 181 211 242 273 303 334 364 3031 031 090 151 212 243 304 365 31

Julian Date Calendar (Leap Year)

Day Jan Feb Mar Apr May June July Aug Sep Oct Nov Dec Day1 001 032 061 092 122 153 183 214 245 275 306 336 12 002 033 062 093 123 154 184 215 246 276 307 337 23 003 034 063 094 124 155 185 216 247 277 308 338 34 004 035 064 095 125 156 186 217 248 278 309 339 45 005 036 065 096 126 157 187 218 249 279 310 340 56 006 037 066 097 127 158 188 219 250 280 311 341 67 007 038 067 098 128 159 189 220 251 281 312 342 78 008 039 068 099 129 160 190 221 252 282 313 343 89 009 040 069 100 130 161 191 222 253 283 314 344 9

10 010 041 070 101 131 162 192 223 254 284 315 345 1011 011 042 071 102 132 163 193 224 255 285 316 346 1112 012 043 072 103 133 164 194 225 256 286 317 347 1213 013 044 073 104 134 165 195 226 257 287 318 348 1314 014 045 074 105 135 166 196 227 258 288 319 349 1415 015 046 075 106 136 167 197 228 259 289 320 350 1516 016 047 076 107 137 168 198 229 260 290 321 351 1617 017 048 077 108 138 169 199 230 261 291 322 352 1718 018 049 078 109 139 170 200 231 262 292 323 353 1819 019 050 079 110 140 171 201 232 263 293 324 354 1920 020 051 080 111 141 172 202 233 264 294 325 355 2021 021 052 081 112 142 173 203 234 265 295 326 356 2122 022 053 082 113 143 174 204 235 266 296 327 357 2223 023 054 083 114 144 175 205 236 267 297 328 358 2324 024 055 084 115 145 176 206 237 268 298 329 359 2425 025 056 085 116 146 177 207 238 269 299 330 360 2526 026 057 086 117 147 178 208 239 270 300 331 361 2627 027 058 087 118 148 179 209 240 271 301 332 362 2728 028 059 088 119 149 180 210 241 272 302 333 363 2829 029 060 089 120 150 181 211 242 273 303 334 364 2930 030 090 121 151 182 212 243 274 304 335 365 3031 031 091 152 213 244 305 366 31

Flow Chart For A Discontinuity

Discontinuity

Chapter 2 - Visual Inspection

Common Definitions and ExamplesAligned rounded indications

Four or more indications in a line, where each is separated from the adjacent indication by less then 1/16 inch or D, whichever is greater, where D is the major diameter of the larger of the adjacent indication.

Arc strikeAny localized heat-effected zone or change in the contour of

the surface of the finished weld or adjacent base metal resulting from an arc or heat generated by the passage of electrical energy between the surface of the finished weld or base metal and a current source,such as welding electrodes or magnetic particle inspection prods.

Burn throughA void or open hole that extends through a backing ring, strip, fused root, or adjacent base metal.

BurstA rupture caused by forging at improper temperatures. Bursts may be either internal or external to the

surface.

Cold shutThe result of pouring metal over solidified metal.

Crack or tearA linear rupture of metal under stress.

Crater pitAn approximately circular surface condition exceeding into

the weld in an irregular manner caused by insufficient filler metal at the weld stop.

DefectOne or more flaws whose aggregate; size, shape, orientation,

location, or properties do not meet the specified acceptance criteria and are rejectable.

DiscontinuityAny interruption in the normal physical structure or

configuration of a part, which will cause a detectable indication or signal when nondestructively examined.

EvaluationA review, following interpretation of the indications noted, to determine whether they meet specified

acceptance criteria.

aligned rounded indications with crack

crack

crater pit

False indicationAn indication that is interpreted to be caused by a condition other than a discontinuity or imperfection.

Heat checksFissures or tears in the weld heat affected zone of material containing low melting point.

ImperfectionA departure of quality characteristic from its intended condition.

IndicationEvidence of a discontinuity that requires interpretation to determine its significance.

Incomplete fusionLack of complete fusion of some portion of the metal in a

weld joint with adjacent metal. The adjacent metal may be either base metal or previously deposited weld metal, or consumable insert.

Incomplete penetrationLack of penetration of the weld through the thickness of the

joint, or penetration which is less than specified.

InterpretationThe determination of whether indications are relevant,nonrelevant, or false.

Lap (forgings)Folding of metal on the surface of the forging, usually occurs when some of the forging metal is squeezed out between the two dies.

Linear indicationAn indication in which the length is equal to or

greater than three times the width.

Melt throughA convex or concave irregularity on the surface of a backing ring or strip, fused root, or adjacent base metal

resulting from fusion completely through a localized region but without development of a void or open hole.

Non-linear rounded indicationsIndication whose length is less than three times its width.

Nonrelevant indicationsAn indication that is caused by a condition or type of discontinuity that is not relevant.

incomplete fusion

incomplete penetration

incomplete penetration

OxidationA condition resulting from partial or complete lack of inert gas shielding of a surface which is heated

during welding resulting in formation of oxide on the surface. This condition may range from slight oxidation evidenced by a multicolored or tightly adhering black film to the extreme of a very rough surface having a crystalline appearance.

PorosityGas pockets or voids in weld metal or castings.

Quench crackA crack formed as a result of thermal stresses produced by

rapid cooling from a high temperature.

Root surface concavityA depression on the root surface of a weld which may be due

to gravity, internal purge, or shrinkage.

Root surface centerline crease or shrinkageAn intermittent or continuous peripheral centerline concavity formed on the root surface.

Root undercutA groove in the internal surface of a base metal or backing ring or strip along the edge of the root of the

weld.

ShrinkageVoid, or voids, that may occur in molten metal due to

contraction during solidification.

SlagNon-metallic solid material entrapped in the weld metal,

between weld metal and base metal, or in a casting.

Tungsten inclusionTungsten entrapped in the weld deposit.

UndercutA groove melted into the base metal at the toe of the weld and left unfilled by weld metal.

Unfused chapletA metal support used in the casting process, which has not

fused with casting material.

Weld spatterMetal particles which deposit on the surface of the weld or

adjacent base metal during welding and which do not form a part of the weld.

porosity

slag

weld spatter

Chapter 3 - Liquid Penetrant Testing

Common Terms and DefinitionsAlkaline

Any soluble mineral salt or mixtures of salt capable of neutralizing acids.

Angstrom Unit (A)A unit of length equal to 108 cm and used to express wavelengths of light; i.e., electromagnetic radiation.

BackgroundThe surface upon which an indication is viewed. It may be the natural surface of the test article or it may be

the developer coating on the surface. This background may contain traces of unremoved penetrant (fluorescent or visible), which, if present, can interfere with the visibility of indications.

Background FluorescenceFluorescent residues observed over the general surface of the test article during fluorescent penetrant

inspection.

BathTerm used colloquially to designate the liquid penetrant inspection materials into which test articles are

immersed during inspection process.

Black LightLight radiation in the near ultraviolet range of wavelengths (3200 to 4000 A), just shorter than visible light.

Black Light FilterA filter that transmits black light while suppressing visible light and hard ultraviolet radiation with

wavelengths less than 3200 angstroms.

BleedoutThe action of the entrapped Penetrant in spreading out from surface discontinuities to form an indication.

BlottingThe action of the developer in soaking up the entrapped penetrant from surface discontinuities to form an

indication.

Capillary Action or CapillarityThe tendency of liquids to penetrate or migrate into small openings such as cracks, pits, or fissures.

Carrier Fluid (Vehicle or Medium)A fluid in which liquid penetrant inspection materials are dissolved or suspended.

CleanFree from interfering solid or liquid contamination on the surface.

Comparative Test BlockAn intentionally cracked metal block having two separate but adjacent areas for the application of different

penetrants so that a direct comparison of their relative effectiveness can be obtained. Can also be used to evaluate penetrant test techniques and test conditions.

Contact EmulsifierAn emulsifier that begins emulsifying penetrant upon simple contact with the penetrant; usually oil-base

(Lipophilic).

ContrastThe difference in visibility (brightness or coloration) between an indication and the surrounding surface.

Dark Adaptation The adjustment of the eyes when one passes from a bright to a darkened area.

Detergent Remover A penetrant remover that is a solution of a detergent in water. Also Hydrophilic Emulsifier.

Developer A material that is applied to the test article surface after excess penetrant has been removed and that is

designed to enhance the penetrant bleedout to form indications. The developer may be a fine powder, a solution that dries to a fine powder, or a suspension (in solvent, water, alcohol, etc.) that dries leaving an absorptive film on the test surface.

Developing Time The elapsed time necessary for the applied developer to bring out indications from penetrant entrapments.

Also called Development Time.

Dragout The carryout or loss of penetrant materials as a result of their adherence to the articles being processed.

Drain Time That portion of the penetrant inspection process during which the excess penetrant, emulsifier, detergent

remover, or developer is allowed to drain from the test article.

Dry Developer A fine, dry powder developer that does not employ a carrier fluid.

Drying Oven An oven used for drying test articles.

Drying Time A time allotted for a test article to dry.

Dual-response Penetrant A penetrant that contains a combination of visible and fluorescent dyes.

Dwell Time The total time that the penetrant or emulsifier is in contact with the test surface, including the time required

for application and the drain time. Also see Emulsification Time.

Electrostatic Spraying A technique of spraying wherein the material being sprayed is given a high electrical charge while the test

article is grounded.

Emulsification Time The period of time that an emulsifier is permitted to combine with the penetrant prior to removal. Also

called Emulsifier Dwell Time.

Emulsifier A liquid that combines with an oily penetrant to make the penetrant water-washable. Also see Hydrophilic

Emulsifier and Lipophilic Emulsifier.

Flash Point The lowest temperature at which a volatile, flammable liquid will give off enough vapor to make a

combustible explosive mixture in the air space surrounding the liquid surface.

Fluorescence The emission of visible radiation by a substance as a result of, and only during, the absorption of black light

radiation.

Fluorescent Dye Penetrant An inspection penetrant that is characterized by its ability to fluoresce when excited by black light.

Halogen (Halogenous) Any of four very active nonmetallic elements; chlorine, iodine, fluorine and bromine.

Hydrophilic Emulsifier A water-base agent that, when applied to an oily penetrant, renders the penetrant water-washable. Can be

used as a Contact Emulsifier, but more often the emulsifier is added to the water rinse and accompanied by some form of mechanical agitation or scrubbing to remove excess penetrant. Sometimes called a Hydrophilic Scrubber.

Leak Testing A technique of liquid penetrant testing in which the penetrant is applied to one side of the surface while the

other side is inspected for indications that would indicate a through-leak or void.

Lipophilic Emulsifier An oil-base agent that, when applied to an oily penetrant, renders the penetrant water-washable. Usually

applied as a Contact Emulsifier.

Near Surface Discontinuity A discontinuity not open to, but located near, the surface of a test article.

Nonaqueous Wet Developer A developer in which the developing powder is applied as a suspension in a quick-drying solvent. Also

called Solvent Developer.

Penetrability The property of a penetrant that causes it to find its way into very fine openings, such as cracks.

Penetrant A liquid (sometimes gas) capable of entering discontinuities open to the surface, and which is adapted to

the inspection process by being made highly visible in small traces. Fluorescent penetrants fluoresce brightly under black light while the visible penetrants are intensely colored to be noticeable under visible light.

Post-emulsification Penetrant A penetrant that requires the application of a separate emulsifier to render the surface penetrant water-

washable. Also can be removed by applying a solvent remover.

Precleaning The removal of surface contaminants or smeared metal from the test article so that they cannot interfere

with the penetrant inspection process.

Quenching of Fluorescence The extinction of fluorescence by causes other than removal of black light (the exciting radiation).

Resolution The property of a test system that enables the separation of indications of close proximity in a test article..

Rinse The process of removing liquid penetrant inspection materials from the surface of an article by washing or

flooding with another liquid-usually water. Also called Wash.

See-ability The characteristic of an indication that enables the observer to see it against the conditions of background,

outside light, etc.

Self-developing Penetrant A penetrant not requiring the use of a developer. Useful for production work in the detection of gross

discontinuities.

Sensitivity The ability of the penetrant process to detect minute surface discontinuities.

Solvent Removed A penetrant-removal technique wherein the excess penetrant is washed or wiped from the test surface with

a solvent remover.

Solvent Remover A volatile liquid used to remove excess surface penetrant from the test article. Sometimes called Penetrant

Remover.

Surface Tension That property of liquids which, due to molecular forces, tends to bring the contained volume into a form

having the least superficial area.

Viscosity The state or degree of being viscous. The resistance of a fluid to the motion of its particles.

Visible Dye Penetrant An inspection penetrant that is characterized by its intense visible color-usually red. Also called Color

Contrast or Nonfluorescent Penetrant.

Water-soluble Developer A developer in which the developer powder is dissolved in a water carrier to form a solution. Not a

suspension.

Water-suspended Particle Developer A developer in which the developer particles are mixed with water to form a suspension.

Water-wash A penetrant-removal technique wherein excess penetrant is washed or flushed from the test surface with

water.

Water-washable Penetrant A type of penetrant that contains its own emulsifier, making it water-washable.

Water Tolerance The amount of water that a penetrant, emulsifier, or wet developer can absorb before its effectiveness is

impaired.

Wet Developer A developer in which the developer powder is applied as a suspension or solution in a liquid-usually water

or alcohol.

Wetting Ability The ability of a liquid to spread out spontaneously and adhere to the test article's surfaces.

Prorated Maximum Number of Indications

MAXIMUM OF 6 INDICATIONS IN A 36 INCH SQUARE AREA

Actual Area 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

Prorated Indications

0 0 0 0 0 1 1 1 1 1 1 2 2 2 2 2 2 3 3 3 3 3 3 4 4 4 4 4 4 5 5 5 5 5 5 6


Actual Area 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36


0 0 0 0 1 1 1 1 2 2 2 2 2 3 3 3 3 4 4 4 4 4 5 5 5 5 6 6 6 6 6 7 7 7 7 8


Actual Area 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36


0 0 0 1 1 1 1 2 2 2 3 3 3 3 4 4 4 5 5 5 5 6 6 6 6 7 7 7 8 8 8 8 9 9 9 10


Actual Area 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36


0 0 1 1 1 2 2 2 3 3 3 4 4 4 5 5 5 6 6 6 7 7 7 8 8 8 9 9 9 10 10 10 11 11 11 12


Actual Area 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36


0 0 1 1 2 2 3 3 4 4 4 5 5 6 6 7 7 8 8 8 9 9 10 10 11 11 12 12 12 13 13 14 14 15 15 16

(MAX # OF INDICATIONS/36) X ACTUAL AREA = NEW MAX # OF INDICATIONS

Areas of CirclesDiameter (inches) Area (square inches) Diameter (inches) Area (square inches)

1/32 .0008 .0195 .00033/64 .0017 .020 .00031/16 .0031 .024 .00055/64 .0048 .025 .00053/32 .0069 .0275 .00067/64 .0094 .031 .00081/8 .0123 .034 .0009

9/64 .0155 .037 .00115/32 .0192 .039 .0012

11/64 .0232 .048 .00183/16 .0276 .049 .0019

13/64 .0324 .050 .00207/32 .0376 .055 .0024

15/64 .0431 .075 .00441/4 .0491 .078 .0048--- --- .100 .0079

Area = π r²

Penetrant Wetting Characteristics

θ

Droplet

Good Wetting

θ

Droplet

Poor Wetting

Droplet

θ

Chapter 4 - Magnetic Particle Testing

Common Definitions and Examples

Air gapWhen a magnetic circuit contains a small gap, which the magnetic flux must cross, the space is referred to

as an air gap. Cracks produce small air gaps on the surface of an article.

Alternating currentElectric current periodically reversing in polarity or direction of flow.

AmpereThe unit of electrical current. One ampere is the current that flows through a conductor having a resistance

of one ohm at a potential of one volt.

Ampere turnsThe product of the number of turns in a coil and the number of amperes flowing through it. A measure of

the magnetizing or demagnetizing strength of the coil.

BathThe suspension of iron oxide particles in a liquid vehicle (light oil or water).

Black lightRadiant energy in the near ultraviolet range. This light has a wavelength of 3200 to 4000 angstrom units

(A), peaking at 3650 A, on the spectrum. This between visible light and ultraviolet light.

Black light filterA filter that transmits black light while surprising the transmission of visible light and harmful ultraviolet

radiation.

Carbon steelSteel that does not contain significant amounts of alloying elements other than carbon and maganese.

Carrier fluidThe fluid in which fluorescent and non-fluorescent magnetic particles are suspended to facilitate their

application in the wet method.

Central conductorAn electrical conductor that is passed through the opening in a ring or tube, or any hole in an article, for the

purpose of creating a circular field in the ring or tube, or around the hole.

Circular fieldSee Field, Circular Magnetic.

Circular magnetizationA method of inducing a magnetic field in an article so that the magnetic lines of force take the form of

concentric rings about the axis of the current. This is accomplished by passing the current directly through the article or through a conductor which passes into or through a hole in the article. The circular method is applicable for the detection of discontinuities with axes approximately parallel to the axis of current through the article.

Coercive force The reverse magnetizing force necessary to remove residual magnetism in demagnetizing an article.

Coil shotA pulse of magnetizing current passed through a coil surrounding an article for the purpose of longitudinal

magnetization.

Contact headshotThe electrode, fixed to the magnetic particle testing unit, through which the magnetizing current is drawn.

Contact padsReplaceable metal pads, usually of copper braid, placed on contact heads to give good electrical contact

thereby preventing damage to the article under test.

Continuous method An inspection method in which ample amounts of magnetic particles are applied, or are present on the

piece, during the time the magnetizing current is applied.

CoreThat part of the magnetic circuit that is within the electrical winding.

Curie pointThe temperature at which ferromagnetic materials can no longer be magnetized by outside forces, and at

which they lose their residual magnetism: approximately 1200 to 1600º F (646 to 871º C) for many metals.

Current Flow Technique A technique of circular magnetization in which current is passed through an article via prods or contact

heads. The current may be alternating, half-wave rectified, rectified alternating, or direct.

Current Induction Technique A technique of magnetization in which a circulating current is induced in a ring-shaped component by a

fluctuating magnetic field.

Demagnetization The reduction in the degree of residual magnetism to an acceptable level.

Diamagnetic Materials whose atomic structure won't permit any real magnetization. Materials such as bismuth and

copper are diamagnetic.

Diffused Indications Indications that are not clearly defined, such as indications of subsurface defects.

Direct Contact Magnetization A magnetic particle testing technique in which current is passed through the test article. These include

headshots and prod shots.

Direct Current An electrical current, which flows steadily in one direction

Distorted Field A field that does not follow a straight path or have a uniform distribution. This occurs in irregularly shaped

objects.

Dry Medium Magnetic particle inspection in which the particles employed are in the dry powder form.

Dry Powder Finely divided ferromagnetic particles suitably selected and prepared for magnetic particle inspection.

Electromagnet A magnet created by inserting a suitable metal core within or near a magnetizing field formed by passing

electric current through a coil of insulated wire.

Etching The process of exposing subsurface conditions of metal articles by removal of the outside surface through

the use of chemical agents. Due to the action of the chemicals in eating away the surface, various surface or subsurface conditions are exposed or exaggerated and made visible to the eye.

Ferromagnetic A term applied to materials that can be magnetized and strongly attracted by a magnetic field.

Field, Circular Magnetic Generally the magnetic field in and surrounding any electrical conductor or article resulting from a current

being passed through the conductor or article or from prods.

Field, Longitudinal Magnetic A magnetic field wherein the flux lines traverse the component in a direction essentially parallel with the

axis of the magnetizing coil or to a line connecting the two poles at the magnetizing yoke.

Field, Magnetic The space within and surrounding a magnetized article, or a conductor carrying current in which the

magnetic force is present.

Field, Magnetic Leakage The magnetic field that leaves or enters the surface of an article at a magnetic pole.

Field, Multidirectional A magnetic field that is the result of two magnetic forces impressed upon the same area of a magnetizable

object at the sametime-sometimes called a "vector field."

Field, Residual Magnetic The field that remains in magnetizable material after the magnetizing force has been removed

Flash Magnetization Magnetization by a current flow of very brief duration.

Fluorescence The emission of visible radiation by a substance as the result of and only during the absorption of black

light radiation.

Fluorescent Magnetic Particle Inspection The magnetic particle inspection process employing a finely divided fluorescent ferromagnetic inspection

medium that fluoresces when activated by black light.

Flux Density The normal magnetic flux per unit area. It is designated by the letter "B" and is expressed in telsa (SI units)

or gauss (cgs units).

Flux Leakage Magnetic lines of force which leave and enter an article at poles on the surface.

Flux Lines Imaginary magnetic lines used as a means of explaining the behavior of magnetic fields. Their conception

is based on the pattern of lines produced when iron filings are sprinkled over a piece of paper laid over a permanent magnet. Also called Lines of Force.

Flux Penetration, Magnetic The depth to which a magnetic flux is present in an article.

Furring Buildup or bristling of magnetic particles due to excessive magnetization of the article.

Gauss The unit of flux density. Numerically, one gauss is one line of flux per square centimeter of area and is

designated by the letter "B."

Head Shot A short pulse of magnetizing current passed through an article or a central conductor while clamped

between the head contacts of a stationary magnetizing unit for the purpose of circularly magnetizing the article.

Heads The clamping contacts on a stationary magnetizing unit.

Horseshoe Magnet A bar magnet bent into the shape of a horseshoe so that the two poles are adjacent. Usually the term applies

to a permanent magnet.

Hysteresis The lagging of the magnetic effect when the magnetic force acting upon a ferromagnetic body is changed;

the phenomenon exhibited by a magnetic system wherein its state is influenced by its previous magnetic history.

Hysteresis Loop A curve showing the flux density, "B," plotted as a function of magnetizing force, "H." As the magnetizing

force is increased to the saturation point in the positive, negative, and positive direction sequentially, the curve forms a characteristic S-shaped loop. Intercepts of the loop with the "B" and "H" axes and the points of maximum and minimum magnetizing force define important magnetic characteristics of the material.

Inductance The magnetism produced in a ferromagnetic body by some outside magnetizing force. The magnetism is

not the result of passing current through the article.

Leakage Field The magnetic field forced out into the air by the distortion of the field within an article.

Light Intensity The light energy reaching a unit of surface area per of time.

Longitudinal Magnetization The process of inducing a magnetic field into the article such that the magnetic lines of force extending

through the article are approximately parallel to the axis of the magnetizing coil or to a line connecting the two poles when yokes (electromagnets) are used.

Magnet, Permanent A highly-retentive metal that has been strongly magnetized; i.e., the alloy Alnico.

Magnetic Field Indicator An instrument designed to detect and/or measure the flux density and polarity of magnetic fields.

Magnetic Field Strength The measured intensity. of a magnetic field at a point always external to the magnet or conductor; usually

expressed in amperes per meter or oersted (Oe).

Magnetic Material Those materials that are attracted by magnetism.

Magnetic Particles Finely divided ferromagnetic material.

Magnetic Particle Inspection A nondestructive inspection method for locating discontinuities in ferromagnetic materials.

Magnetic Poles Concentration of flux leakage in areas of discontinuities, shape changes, permeability variations, etc.

Magnetic Writing A form of nonrelevant indications caused when the surface of a magnetized part comes in contact with

another piece of ferromagnetic material that is magnetized to a different value.

Magnetizing Current The flow of either alternating, rectified alternating, or direct current used to induce magnetism into the

article being inspected.

Magnetizing Force The magnetizing field applied to a ferromagnetic material to induce magnetization.

Medium The fluid in which fluorescent and nonfluorescent magnetic particles are suspended to facilitate their

application in the wet method.

Near Surface Discontinuity A discontinuity not open to, but located near, the surface of a test article.

Oersted A unit of field strength, which produces magnetic induction and is designated by the letter "H."

Paramagnetic Materials which are slightly affected by a magnetic field. Examples are chromium, manganese, aluminum

and platinum. A small group of these materials are classified as ferromagnetic.

Permeability The ease with which the lines of force are able to pass through an article.

Pole The area on a magnetized article from which the magnetic field is leaving or returning to the article.

Prods Hand-held electrodes attached to cables used to transmit the magnetizing current from the source to the

article under inspection.

Rectified Alternating Current Alternating current, which has been converted into direct current.

Reluctance The resistance of a magnetic material to changes in magnetic field strength.

Residual Magnetism The amount of magnetism that a magnetic material retains after the magnetizing force is removed. Also

called "residual field" or "remanence."

Residual Technique A procedure in which the indicating material is applied after the magnetizing force has been discontinued.

Retentivity The ability of a material to retain a certain portion of residual magnetization. Also known as remanence.

Saturation The point at which increasing the magnetizing force produces no further magnetism in a material.

Sensitivity The capacity or degree of responsiveness to magnetic particle inspection.

Settling Test A procedure used to determine the concentration of magnetic particles in a medium or vehicle.

Skin Effect The description given to alternating current magnetization due to its containment to the surface of a test

article.

Solenoid (Coil) An electric conductor formed into a coil often wrapped around a central core of highly permeable material.

AT =45,000 (+/- 10%)

(L/D)

A =

45,000 (+/- 10%)(L/D)( )

T

)T =

45,000 (+/- 10%)(L/D)(

AD =

45,000 (+/- 10%)

L(AT)

L =45,000 (+/- 10%)

ATx D

A = ampereT = turns of the coilL = length of the itemD = diameter or cross section of the item

The minimum L/D ratio is 2The maximum L used in calculations is 20 inches

Suspension The correct term applied to the liquid bath in which the ferromagnetic particles used in the wet magnetic

particle inspection method are suspended.

Test Article An article containing known artificial or natural defects used for checking the efficiency of magnetic

particle flaw detection processes.

Wet Medium An inspection employing ferromagnetic particles suspended in a liquid (oil or water) as a vehicle.

Yoke A U-shaped or C-shaped piece of highly permeable magnetic material, either solid or laminated, sometimes

with adjustable pole pieces (legs) around which is wound a coil carrying the magnetizing current.

Yoke Magnetization A longitudinal magnetic field induced in an article or in an area of an article by means of an external

electromagnet shaped like a yoke.

Longitudinal Magnetization Math Formula

Prorated Maximum Number of Indications


Actual Area 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36


0 0 0 0 0 1 1 1 1 1 1 2 2 2 2 2 2 3 3 3 3 3 3 4 4 4 4 4 4 5 5 5 5 5 5 6


Actual Area 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36


0 0 0 0 1 1 1 1 2 2 2 2 2 3 3 3 3 4 4 4 4 4 5 5 5 5 6 6 6 6 6 7 7 7 7 8


Actual Area 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36


0 0 0 1 1 1 1 2 2 2 3 3 3 3 4 4 4 5 5 5 5 6 6 6 6 7 7 7 8 8 8 8 9 9 9 10


Actual Area 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36


0 0 1 1 1 2 2 2 3 3 3 4 4 4 5 5 5 6 6 6 7 7 7 8 8 8 9 9 9 10 10 10 11 11 11 12


Actual Area 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36


0 0 1 1 2 2 3 3 4 4 4 5 5 6 6 7 7 8 8 8 9 9 10 10 11 11 12 12 12 13 13 14 14 15 15 16

(MAX # OF INDICATIONS/36) X ACTUAL AREA = NEW MAX # OF INDICATIONS

Areas of CirclesDiameter (inches) Area (square inches) Diameter (inches) Area (square inches)

1/32 .0008 .0195 .00033/64 .0017 .020 .00031/16 .0031 .024 .00055/64 .0048 .025 .00053/32 .0069 .0275 .00067/64 .0094 .031 .00081/8 .0123 .034 .0009

9/64 .0155 .037 .00115/32 .0192 .039 .0012

11/64 .0232 .048 .00183/16 .0276 .049 .0019

13/64 .0324 .050 .00207/32 .0376 .055 .0024

15/64 .0431 .075 .00441/4 .0491 .078 .0048--- --- .100 .0079

Area = π r²

Common Types of Magnetization

Central Conductor (circular) Horse shoe (longitudinal)

Coil Shot (longitudinal)

Yoke (longitudinal)

Prods (circular)

Theory: “Right–Hand Rule”

SN

Horseshoe Magnet

Electromagnetic Yoke

Workpiece

Discontinuities

Weld

Magnetic field

(+)

(-) CURRENT FLOW

Hysteresis Curve

O – A = Referred to as the virgin curveA = Saturation pointB = Residual field

O – C = Coercive forceD = Reverse saturation pointE = Reverse residual field

O – F = Reverse coercive force

C O F

B

E

D

A

B+ (FLUX DENSITY)

B- (FLUX DENSITY OF OPPOSITE POLARITY TO B+)

H- (MAGNETIZING FORCE OF OPPOSITE POLARITY TO H+) H= (MAGNETIZING FORCE)

SLENDER LOOP

HIGH PERMEABILITYLOW RENTENTIVITYLOW COERCIVE FORCELOW RELUCTANCELOW RESIDUAL MAGNETISM

WIDE LOOP

LOW PERMEABILITYHIGH RENTENTIVITYHIGH COERCIVE FORCEHIGH RELUCTANCEHIGH RESIDUAL MAGNETISM

Magnetic Particle Field Indicator (Pie Gage)

1 in.

1/32 in max

Eight low carbon steel pie sections, furnace brazed together

Artificial flaw (all segment interfaces)

Nonferrous handle of anyConvenient length

Braze weld or mechanically attach nonferrous trunnions

1/8

Copper plate0.010 in + 0.001 in thick

Chapter 5 - Ultrasonic Testing

Common Terms and Definitions

A-scan DisplayA display in which the received signal is displayed as a vertical displacement from the horizontal sweep

time trace, while the horizontal distance between any two signals represents the sound path distance (or time of travel) between the two.

Absorption Coefficient, LinearThe fractional decrease in transmitted intensity per unit of absorber thickness. It is usually designated by

the symbol and expressed in units of cm-1.

Acceptance StandardA control specimen containing natural or artificial discontinuities that are well defined and, in size or

extent, similar to the maximum acceptable in the product. Also may refer to the document defining acceptable discontinuity size limits.

Acoustic ImpedanceThe factor which controls the propagation of an ultrasonic wave at a boundary interface. It is the product of

the material density and the acoustic wave velocity within that material.

Amplifier A device to increase or amplify electrical impulses.

Amplitude, IndicationThe vertical height of a received indication, measured from base-to-peak or peak-to-peak.

Angle Beam TestingA testing method in which transmission is at an angle to the sound entry surface.

Angle of IncidenceThe angle between the incident (transmitted) beam and a normal to the boundary interface.

Angle of ReflectionThe angle between the reflected beam and a normal to the boundary interface. The angle of reflection is

equal to the angle of incidence.

Angle of RefractionThe angle between the refracted rays of an ultrasonic beam and the normal (or perpendicular line) to the

refracting surface.

Angle TransducerA transducer that transmits or receives the acoustic energy at an acute angle to the surface to achieve a

specific effect such up the setting up of shear or surface waves in the part being inspected.

AnisotropicA condition in which properties of a medium (velocity, for example) vary according to the direction in

which they are measured.

Array TransducerA transducer made up of several piezoelectric elements individually connected so that the signals they

transmit or receive nay be treated separately or combined as desired.

Attenuation CoefficientA factor which is determined by the degree of scatter or absorption of ultrasound energy per unit distance

traveled.

AttenuatorA device for measuring attenuation, usually calibrated in decibels (dB).

B-scan DisplayA cathode-ray tube display in which the received signal is displayed as an illuminated spot. The face of the

CRT represents the area of a vertical plane through the material. The display shows the location of a discontinuity, as it would appear in a vertical section view through the thickness direction of the material.

Back ReflectionThe signal received from the back surface of a test object.

Back ScatterScattered signals that are directed back to the transmitter/receiver.

Background NoiseExtraneous signals caused by signal sources within the ultrasonic testing system, including the material in

test.

Barium Titanate (Polycrystalline Barium Titanate - BaTiO3)A ceramic transducer material composed of many individual crystals fired together and polarized by the

application of a dc field.

BaselineThe horizontal line across the bottom of the CRT created by the sweep circuit.

Basic CalibrationThe procedure of standardizing an instrument using calibration reflectors described in an application

document.

Bi-modalThe propagation of sound in a test article where at least a shear wave and a longitudinal wave exists. The

operation of angle beam testing at less than first critical angle.

Boundary IndicationA reflection of an ultrasonic beam from an interface.

Broad BandedHaving a relatively wide frequency bandwidth. Used to describe pulses which display a wide frequency

spectrum and receivers capable of amplifying them.

C-scanA data presentation method yielding a plan (top) view through the scanned surface of the part. Through

gating, only indications arising from the interior of the test object are indicated.

CalibrationTo determine or mark the graduations of the ultrasonic system's display relative to a known standard or

reference.

Calibration ReflectorA reflector with a known dimensioned surface established to provide an accurately reproducible reference.

CollimatorAn attachment designed to reduce the ultrasonic beam spread.

CompensatorAn electrical matching network to compensate for circuit impedance differences.

Compressional WaveA wave in which the particle motion or vibration is in the same direction as the propagated wave

(longitudinal wave).

Contact TestingA technique of testing in which the transducer contacts the test surface, either directly or through a thin

layer of couplant.

Contact TransducerA transducer which is coupled to a test surface either directly or through a thin film of couplant.

Continuous WaveA wave that continues without interruption.

Contracted SweepA contraction of the horizontal sweep on the viewing screen of the ultrasonic instrument. Contraction of

this sweep permits viewing reflections occurring over a greater sound-path distance or duration of time.

Corner EffectThe strong reflection obtained when an ultrasonic beam is directed toward the inner section of two or three

mutually perpendicular surfaces.

CouplantA substance used between the face of the transducer and test surface to permit or improve transmission of

ultrasonic energy across this boundary or interface. Primarily used to remove the air in the interface.

Critical AngleThe incident angle of the sound beam beyond which a specific refracted mode of vibration no longer exists.

Cross TalkAn unwanted condition in which acoustic energy is coupled from the transmitting crystal to the receiving

crystal without propagating along the intended path through the material.

Damping (transducer)Limiting the duration of vibration in the search unit by either electrical or mechanical means.

Dead ZoneThe distance in a material from the sound entry surface to the nearest inspectable sound path.

Decibel (dB)The logarithmic expression of a ratio of two amplitudes or intensities of acoustic energy

DelaminationA laminar discontinuity, generally an area of unbonded materials.

Delay LineA material (liquid or solid) placed in front of a transducer to use a time delay between the initial pulse and

the front surface reflection.

Delayed SweepA means of delaying the start of horizontal sweep, hereby eliminating the presentation of early response

data.

Delta EffectAcoustic energy re-radiated by a discontinuity.

DetectabilityThe ability of the ultrasonic system to locate a discontinuity.

DiffractionThe deflection, or "bending," of a wave front when passing the edge or edges of a discontinuity.

Diffuse ReflectionScattered, incoherent reflections caused by rough surfaces or associate interface reflection of ultrasonic

waves from irregularities of the same order of magnitude or greater than the wavelength.

DiscontinuityAn interruption or change in the physical structure or characteristics of a material.

Dispersion, SoundScattering of an ultrasonic beam as a result of diffuse reflection from a highly-irregular surface.

Distance Amplitude Correction (DAC)Compensation of gain as a function of time for difference in amplitude of reflections from equal reflectors

at different sound travel distances. Also referred to as time corrected gain (TCG), time variable gain (TVG) and sensitivity time control (STC).

DivergenceSpreading of ultrasonic waves after leaving search unit, and is a function of diameter and frequency.

Dual-Element TechniqueThe technique of ultrasonic testing using two transducers with one acting as the transmitter and one as the

receiver.

Dual-Element Transducer A single transducer housing containing two piezoelectric elements, one for transmitting and one for

receiving.

Effective PenetrationThe maximum depth in a material at which the ultrasonic transmission is sufficient for proper detection of

discontinuities.

Electrical NoiseExtraneous signals caused by externally radiated electrical signals or from electrical interferences within

the ultrasonic instrumentation.

Electromagnetic Acoustic Transducer (EMAT)A device using the magneto effect to generate and receive acoustic signals for ultrasonic nondestructive

tests.

Far FieldThe region beyond the near field in which areas of high and low acoustic intensity cease to occur.

First LegThe sound path beginning at the exit point of the probe and extending to the point of contact opposite the

examination surface when performing angle beam testing.

Focused Transducer A transducer with a concave face which converges the acoustic beam to a focal point or line at a defined

distance from the race.

Focusing Concentration or convergence of energy into a smaller beam.

Frequency Number of complete cycles of a wave motion passing a given point in a unit time (1 second); number of

times a vibration is repeated at the same point in the same direction per unit time (usually per second).

GateAn electronic means to monitor an associated segment of time, distance, or impulse.

GhostAn indication which has no direct relation to reflected pulses from discontinuities in the materials being

tested.

Hertz (Hz)One cycle per second.

Horizontal LinearityA measure of the proportionality between the positions of the indications appearing on the baseline and the

positions of their sources.

Immersion TestingA technique of testing, using a liquid as an ultrasonic couplant, in which the test part and at least the

transducer face is immersed in the couplant and the transducer is not in contact with the test part.

Impedance (acoustic)A material characteristic defined as a product of particle velocity and material density.

Indication (ultrasonics)The signal displayed or read on the ultrasonic systems display.

Initial PulseThe first indication which may appear on the screen. This indication represents the emission of ultrasonic

energy from the crystal face (main bang).

InterfaceThe physical boundary between two adjacent acoustic mediums.

InsonificationIrradiation with sound.

IsotropyA condition in which significant medium properties (velocity, for example) are the same in all directions.

Lamb WaveA type of ultrasonic vibration guided by parallel surfaces of thin mediums capable of propagation in

different modes.

Linearity (area)A system response in which a linear relationship exists between amplitude of response and the

discontinuity sizes being evaluated necessarily limited by the size of the ultrasonic beam.

Linearity (depth)A system response where a linear relationship exists with varying depth for a constant size discontinuity.

Longitudinal Wave VelocityThe unit speed of propagation of a longitudinal (compressional) wave through a material.

Loss of Back ReflectionAbsence of or a significant reduction of an indication from the back surface of the article being inspected.

Major Screen DivisionsThe vertical graticule used to divide the CRT into 10 equal horizontal segments.

ManipulatorA device used to orient the transducer assembly. As applied to immersion techniques, it provides either

angular or normal incidence and fixes the transducer-to-part distance.

Material NoiseExtraneous signals caused by the structure of the material being tested.

Miniature Angle Beam BlockA specific type of reference standard used primarily for the angle beam method, but also used for straight

beam and surface wave tests.

Minor Screen DivisionsThe vertical graticule used to divide the CRT into fifty equal segments. Each major screen division is

divided into five equal segments or minor divisions.

Mode ConversionThe change of ultrasonic wave propagation upon reflection or refraction at acute angles at an interface.

ModeThe manner in which acoustic energy is propagated through a material as characterized by the particle

motion of the wave.

Multiple Back ReflectionsRepetitive indications from the back surface of the material being examined.

NanosecondOne billionth of a second.

Narrow BandedA relative term denoting a restricted range of frequency response.

Near FieldA distance immediately in front of a transducer composed of complex and changing wave front

characteristics. Also known as the Fresnel field.

NodeThe point on the examination surface where the V-path begins or ends.

NoiseAny undesired indications that tend to interfere with the interpretation or processing of the ultrasonic

information; also referred to as "grass."

Normal IncidenceA condition where the angle of incidence is zero.

OrientationThe angular relationship of a surface, plane, defect axis, etc., to a reference plane or sound entry surface.

Penetration (ultrasonic)Propagation of ultrasonic energy through an article.

Phased ArrayA mosaic of probe elements in which the timing of the element's excitation can be individually controlled

to produce certain desired effects, such as steering the beam axis or focusing the beam.

Piezoelectric EffectThe characteristic of certain materials to generate electrical charges when subjected to mechanical

vibrations and, conversely to generate mechanical vibrations when subjected to electrical pulses.

Polarized CeramicsCeramic materials that are sintered (pressed), created (approximately 10000C), and polarized by applying a

direct voltage of a few thousand volts per centimeter of thickness. The polarization is the process that makes these ceramics piezoelectric. Includes sodium bismuth titanate, lead metaniobate, and several materials based on lead zirconate titanate (PZT).

PresentationThe method used to show ultrasonic information. This may include (among others) A-, B-, or C-scans

displayed on various types of recorders, CRTs, LCD’s or computerized displays.

ProbeTransducer or search unit.

PropagationAdvancement of a wave through a medium.

Pulse Echo TechniqueAn ultrasonic test technique using equipment which transmits a series of pulses separated by a constant

period of time; e., energy is not sent out continuously.

Pulse Length Time duration of the pulse from the search unit.

Pulse RateFor the pulse echo technique, the number of pulses transmitted in a unit of time (also called pulse repetition

rate).

Radio Frequency Display (RF)The presentation of unrectified signals in a display.

RangeThe maximum ultrasonic path length that is displayed.

Rarefaction The thinning out or moving apart of the consistent particles in the propagating medium due to the

relaxation phase of an ultrasonic cycle. Opposite in its effect to compression. The sound wave is composed of alternate compressions and refractions of the particles in a material.

Rayleigh Wave/Surface WaveA wave that travels on or close to the surface and readily follows the curvature of the part being examined.

Reflections occur only at sharp changes of direction of the surface.

ReceiverThe section of the ultrasonic instrument that amplifies the electronic signals returning from the test

specimen. Also, the probe that receives the reflected signals.

Reference Blocks A block or series of blocks of material containing artificial or actual discontinuities of one or more

reflecting areas at one or more distances from the sound entry surface. These are used for calibrating instruments and in defining the size and distance of discontinuous areas in materials.

ReflectionThe characteristic of a surface to change the direction of propagating acoustic energy; the return of sound

waves from surfaces.

RefractionA change in the direction and velocity of acoustic energy after it has passed at an acute angle through an

interface between two different mediums.

Refractive IndexThe ratio of the velocity of a incident wave to the velocity of the refracted wave. It is a measure of the

amount a wave will be refracted when it enters the second medium after leaving the first.

Reject/SuppressionAn instrument function or control used for reducing low amplitude signals. Use of this control may affect

vertical linearity.

Repetition RateThe rate at which the individual pulses of acoustic energy are generated; also Pulse Rate.

Resolving PowerThe capability measurement of an ultrasonic system to separate in time two closely spaced discontinuities

or to separate closely spaced multiple reflections.

Resonance TechniqueA technique using the resonance principle for determining velocity, thickness or presence of laminar

discontinuities.

ResonanceThe condition in which the frequency of a forcing vibration (ultrasonic wave) is the same as the natural

vibration frequency of the propagation body (test object), resulting in large amplitude vibrations.

Saturation (scope)A term used to describe an indication of such a size as to exceed full screen height (100%).

Scanning (manual and automatic)The moving of the search unit or units along a test surface to obtain complete testing of a material.

ScatteringDispersion of ultrasonic waves in a medium due to causes other than absorption

Second Leg The sound path beginning at the point of contact on the opposite surface and extending to the point of

contact on the examination surface when performing angle beam testing.

SensitivityThe ability to detect small discontinuities at given distances. The level of amplification at which the

receiving circuit in an ultrasonic instrument is set.

Shear WaveThe wave in which the particles of the medium vibrate in a direction perpendicular to the direction of

propagation.

Signal-to-Noise Ratio (SNR)The ratio of amplitudes of indications from he smallest discontinuity considered significant and those

caused by random factors, such as heterogeneity in grain size, etc.

Skip DistanceIn angle beam tests of plate, pipe, or welds, the linear or surface distance from the sound entry point to the

first reflection point on the same surface.

Snell's LawThe law that defines the relationship between the angle of incidence and the angle of refraction across an

interface, based on a range in ultrasonic velocity.

Specific Acoustic ImpedanceA characteristic which acts to determine the amount of reflection which occurs at an interface and

represents the wave velocity and the product of the density of the medium in which the wave is propagating.

Straight Beam An ultrasonic wave traveling normal to the test surface.

SweepThe uniform and repeated movement of a spot across the screen of a CRT to form the baseline.

Through-Transmission A test technique using two transducers in which the ultrasonic vibrations are emitted by one and received

by the other, usually on the opposite side of the part. The ratio of the magnitudes of vibrations transmitted and received is used as the criterion of soundness.

Tip DiffractionThe process by which a signal is generated from the tip (i.e., top of a fatigue crack) of a discontinuity

through the interruption of an incident sound beam propagating through a material.

Transducer (search unit) An assembly consisting basically of a housing, piezoelectric element, backing material, wear plate

(optional) and electrical leads for converting electrical impulses into mechanical energy and vice versa.

Transmission AngleThe incident angle of the transmitted ultrasonic beam. It is zero degrees when the ultrasonic beam is

perpendicular to the test surface.

TransmitterThe electrical circuit of an ultrasonic instrument that generates the pulses emitted to the search unit. Also

the probe that emits ultrasonic signals.

Two Probe MethodUse of two transducers for sending and receiving. May be either send-receive or through transmission.

Ultrasonic AbsorptionA damping of ultrasonic vibrations that occurs when the wave transverses a medium.

Ultrasonic SpectrumThe frequency span of elastic waves greater than the highest audible frequency, generally regarded as being

higher than 20,000 hertz, to approximately 1000 megahertz.

Ultrasonic SystemThe totality of components utilized to perform an ultrasonic test on a test article.

V-pathThe path of the ultrasonic beam in the test object from the point of entry on the examination surface to the

back surface and reflecting to the front surface again.

VelocityThe speed at which sound travels through a medium.

Video PresentationA CRT presentation in which radio frequency signals nave been rectified and usually filtered.

Water PathThe distance from the face of the search unit to the entry surface of the material under test in immersion

testing.

WavelengthThe distance in the direction of propagation for a wave to go through one complete cycle.

Wedge/ShoeA device used to adapt a straight beam probe for use in a specific type of testing, including angle beam or

surface wave tests and tests on curved surfaces.

WraparoundNonrelevant indications that appear on the CRT as a result of a short pulse repetition rate in the pulser

circuit of the test instrument.

VF

A +MP

L λ = Wavelength

I V = VeloocityT F = FrequencyUDE -

λ =

Common Math Formulas

Wavelength

Crystal Thickness Acoustic Impedance Reflected Acoustic Energyλ2

CT = Crystal thickness

λ= Wavelength

CT =

Use .23 if material is unknown

Energy Transmitted Half Angle Beam Spread Nearfield (nearzone)

Times 2 for full angle beam spread

Decibel Difference Snell’s Law & Angle of Reflection

Rule of thumb: every 6 Db doubles the size of theindication height (pip)

Z1-Z2 2

Z1+Z2

ER = Energy reflectedZ1 = Acoustic impedance material #1Z2 = Acoustic impedance material #2

(ER = 100 )Z = P(V)

Z = Acoustic impedanceP = Materials densityV = Acoustic velocity

ET = EI - ER

ET = Energy transmittedEI = Energy intiated

ER = Energy reflected

D 2 (F)4 (V)

N = Length of the near fieldD = Diameter of the transducerF = Transducer frequencyV = Materials velocity

N =V

D*F

K =V = Velocity of the materialD = Diameter of the transducerF = Frequency of the transducer

1.22

SIN θ = K ( )

A1A2

Db = Decibel differenceLOG = Natural logrithm

A1 = Amplitude number oneA2 = Amplitude number two

Db = 20 [LOG ( ) ]

SIN θ2 * V1

Angle of incidence * 1st critical angle V2 is long = 90 °Critical angle* 2nd critical angle V2 is shear = 90 °Wedge angle

SIN θ1 * V2SIN θ2 =V1

SIN θ1 =V2

Half / Full Sound Path & Skip / Setback Distance

Surface Distance to Defect / Depth of Defect

Calibration Chart – UT Shearwave

PLATETHICKNESS

1" 1/2" 3/4" 1"1 - 1/4" 1/2" 3/4" 1" 1 - 1/4"1 - 1/2" 3/4" 1" 1 - 1/4" 1 - 1/2"

2" 1" 1 - 1/4" 1 - 1/2" 1 - 3/4" 2"

PLATETHICKNESS

1" 1 - 1/2" 1 - 3/4" 2"1 - 1/4" 1 - 3/4" 2" 2 - 1/4" 2 - 1/2"1 - 1/2" 2 - 1/4" 2 - 1/2" 2 - 3/4" 3 - 1/4"

2" 2 - 3/4" 3 - 1/4" 3 - 1/2" 3 - 3/4" 4"

FULL SKIP

* Applicable holes in the M.I. block for calibration

*HALF SKIP

T HALF SKIP = T * TAN θCOS θ

2T FULL SKIP = 2T * TAN θCOS θ

HSP =

T =Member thickness

FSP =

SDD = Sound Path * SIN θ #DD = Sound Path * COS θ

##DD = (Sound Path * COS θ ) - 2T

SDD = Surface distance to defect #DD = Depth of defect during half sound path

##DD = Depth of defect during full sound path T = Member thickness

FPADSCRλ D

P A D S C R λ D r e t i e r e w n i e n t v n y s a e a q e e e s s o v a m u t n r i t l e r e e r u g t a u l t n a a e i l t e e c t t n v i n r y i i c i t o g

o o e t h n t ofn n y i h

p r c c tu e k r hl p. n y is e s ce r s t k

a s a nt l ee s

s

F

Velocity Chart

2 IN 6 IN 6 5

SEC SEC cm 2 SECAirAluminumAluminum OxideBertiliumBororn CarbieBrassCadiumCopperCrown GlassGlycerinGoldIceInconelIronCast IronLeadMagnesiumMercuryMolybdenumMonelNeopreneNickelNylon, 6-6Oil (SAE 30)PlatinumPlexiglassPolyethylenePolystyrenePolyurethaneQuartzRubber, ButylSilverSteel, MildSteel, StainlessTeflonTinTitaniumTungstenUraniumWaterZinc

.001 .013 - - - - .0004

P=gm/cm X 10 X 10 X 10gm

2.7 .25 .12 17- - - - .39 .23 321.82 .51 .35 23- - - - .43 - - - - 26.48.1 .17 .080 36.78.6 .11 .059 248.9 .18 .089 41.62.5 .21 .12 18.9

1.261 .075 - - - - 2.4219.3 .13 .047 62.61.00 .16 .08 3.5- - - - .22 .12 47.2- - - - .23 .13 45.47.22 .18 .10 33.211.4 .085 .03 24.61.7 .23 .12 10

- - - - .057 - - - - 19.610.09 .25 .13 64.2- - - - .21 .11 47.6- - - - .063 - - - - 2.18.3 .22 .12 49.5

- - - - .10 .043 2.90.95 .067 - - - - 1.521.4 .13 .067 69.81.18 .11 .043 3.1

.04 2.5- - - - .07 .02 1.7

15.2- - - - .07 - - - - 1.9

10.5 .14 380.9 .07

.062

7.7 .23 .13 468.03 .23 .12 45.4- - - - .06 - - - - 37.3 .13 .07 24.2

4.54 .24 .12 27.3

.13 .008 6319.25 .20 .11 101

ACOUSTIC IMPEDANCE

7.1 .17 .09 29.61.00 .0584 - - - - 1.48- - - -

MATERIAL

- - - -

DENSITYLONGITUDINAL

VELOCITYSHEAR

VELOCITY

2.20 .23 .087

1.06 .093

Chapter 6 - Eddy Current Testing

Common Terms and DefinitionsAbsolute Coil

A test arrangement which tests the specimen without any comparison to either another portion of the test specimen or to a known reference.

Alternating A voltage, current or magnetic field that reverses direction at regularly recurring intervals.

Bobbin Coil A coil or coil assembly used for eddy current testing by insertion into the test piece; e.g., an inside probe

for tubing. Also referred to as Inside Coil or IP Coil.

Coil Conductor wound in one or more loops to produce an axial magnetic field when current is passed through

it.

Coil SpacingThe axial distance between two encircling coils of a differential system.

Conductivity The willingness of a test circuit or test specimen to conduct current.

Coupling A measure of the degree to which the magnetic field of the coil passes through the test specimen and is

affected by the magnetic field created by the flow of eddy currents.

Defect Resolution A property of a test system which enables the separation of signals due to defects in the test specimen that

are located in close proximity to each other.

Diamagnetic A material having a permeability less than that of a vacuum.

Differential Coil A test arrangement which tests the specimen by comparing the portion being tested with either another

portion of the same specimen or to a known reference specimen.

Discontinuity, Artificial Reference discontinuities, such as holes, grooves, or notches, which are introduced into a reference

standard to provide accurately reproducible sensitivity levels for electromagnetic test equipment.

Double Coil A test arrangement where the alternating current is supplied through one coil while the change in material

condition is measured from a second coil.

Eddy Current A circulating electrical current induced in a conductive material by an alternating magnetic field.

Edge or End Effect The disturbance of the magnetic field and eddy currents due to the proximity of an abrupt change in

geometry (edge, end). The effect generally results in the masking of discontinuities within the affected region.

Effective Depth of Penetration The depth in a material beyond which a test system can no longer detect a change in material properties.

Effective Permeability A hypothetical quantity which is used to describe the magnetic field distribution within a cylindrical

conductor in an encircling coil. The field strength of the applied magnetic field is assumed to be uniform over the entire cross section of the test specimen with the effective permeability, which is characterized by the conductivity and diameter of the test specimen and test frequency, assuming values between zero and one, such that its associated amplitude is always less than one within the specimen.

Electromagnetic Induction The process by which a varying or alternating current (eddy current) is induced into an electrically

conductive test object by a varying electromagnetic field.

Electromagnetic TestingThat nondestructive test method for engineering materials, including magnetic materials, which uses

electromagnetic energy having frequencies less than those of visible light to yield information regarding the quality of the tested material.

Encircling CoilA coil, coils, or coil assembly that surrounds the part to be tested. Coils of this type are also referred to as

circumferential, OD or feed-through coils.

External Reference Differential A differential test arrangement that compares a portion of the test specimen to a known reference standard.

Ferromagnetic A material which, in general, exhibits hysteresis phenomena, and whose permeability is dependent on the

magnetizing force.

Fill Factor For an inside coil, it is the ratio of the outside diameter of the coil squared to the inside diameter of the

specimen squared. For an encircling coil, it is the ratio of the outside diameter of the specimen squared to the inside diameter of the coil squared.

Flux Density A measure of the strength of a magnetic field expressed as a number of flux lines passing through a given

area.

Henry The unit of inductance. More precisely, a circuit in which an electromotive force of one volt is induced

when the current is changing at a rate of one ampere per second will have an inductance of one henry. (Symbol: H)

Hertz The unit of frequency (one cycle per second). (Symbol: Hz)

High Pass Filter An electronic circuit designed to block signals of low frequency while passing high frequency signals.

IACS The International Annealed Copper Standard. A value of conductivity established as a standard against

which other conductivity values are referred to in percent IACS.

Impedance The opposition to current flow in a test circuit or a coil due to the resistance of that circuit or coil, plus the

electrical properties of the coil as affected by the coil's magnetic field.

Impedance Analysis An analytical method which consists of correlating changes in the amplitude, phase, or quadrature

components (or all of these) of a complex test signal voltage to the electromagnetic conditions within the specimen.

Impedance-plane Diagram A graphical representation of the locus of points indicating the variations in the impedance of a test coil as

a function of basic test parameters.

Inductance The inertial element of the electric circuit. An inductor resists any sudden change in the current flowing

through it.

Inductive Reactance The opposition to current flow in a test circuit or coil when an alternating voltage source is applied and due

solely to the electrical properties of the coil as affected by the magnetic field.

Inertia The property of matter which manifests itself as a resistance to any change in the momentum of a body.

Lift-off The distance between a surface probe coil and the specimen.

Lift-off Effect The effect observed due to a change in magnetic coupling between a test specimen and a probe coil

whenever the distance between them is varied.

Low Pass Filter An electronic circuit designed to block signals of high frequency while passing low frequency signals.

Magnetic Field A condition of space near a magnet or current-carrying wire in which forces can be detected.

Magnetic Flux Lines A closed curve in a magnetic field through points having equal magnetic force and direction.

Noise Any undesired signal that tends to interfere with the normal reception or processing of a desired signal.. In

flaw detection, undesired response to dimensional and physical variables (other than flaws) in the test part is called "part noise.

Nonferromagnetic A material that is not magnetizable and hence, essentially not affected by magnetic fields. This would

include paramagnetic materials having a magnetic permeability slightly greater than that of a vacuum and approximately independent bf the magnetizing force and diamagnetic materials having a permeability less than that of a vacuum.

Paramagnetic A material having a permeability which is slightly greater than that of a vacuum, and which is

approximately independent of the magnetizing force.

Permeability A measure of the ease with which the magnetic domains of a material align themselves with an externally

applied magnetic field.

Permeability Variations Magnetic inhomogeneities of a material.

Phase Analysis An instrumentation technique which discriminates between variables in the test part by the different phase

angle changes which these conditions produce in the test signal.

Phase Angle The angle measured in degrees that the current in the test circuit leads or lags the voltage. One complete

cycle is equal to 360°.

Phase Shift A change in the phase relationship between two alternating quantities of the same frequency.

Probe Coil A small coil or coil assembly normally used for surface inspections.

Reference Standard A test specimen used as a basis for calibrating test equipment or as a comparison when evaluating test

results.

Rejection Level The setting of the signal level above or below which all parts are rejectable or in an automatic system at

which objectional parts will actuate the reject mechanism of the system.

Resistance The opposition to current flow in a test circuit or coil based on specific material properties and cross-

sectional area and length of a conductor.

Response Amplitude The property of the test system whereby the amplitude of the detected signal is measured without regard to

phase.

Saturation The degree of magnetization produced in a ferromagnetic material for which the incremental permeability

has decreased substantially to unity.

Self-comparison Differential A differential test arrangement that compares two portions of the same test specimen.

Signal-to-noise Ratio The ratio of response or amplitude of signals of interest to the response or amplitude of signals containing

no useful information.

Single Coil A test arrangement where the alternating current is supplied through the same coil from which the

indication is taken.

Skin Effect A phenomenon where, at high frequencies, the eddy current flow is restricted to a thin layer of the test

specimen close to the coil.

Standard A reference used as a basis for comparison or calibration; a concept that has been established by authority,

custom, or agreement to serve as a model or rule in the measurement of quantity or the establishment of a practice or a procedure.

Standard Depth of Penetration The depth in a test specimen where the magnitude of eddy current flow is equal to 37 percent of the eddy

current flow at the surface.

Two Types of Electrical Current

Direct Current (DC)

- Current flow is constant over time- Current is distributed uniformly over the cross-section of the conductor- Example: battery

Current strength and direction remain constant over time

Time

Alternating Current (AC)

- Current flow varies over time- Current flows at or near the surface of the conductor - this phenomenon is called the skin

effect- Example: 60 cycle ac in wall sockets

Current strength varies over time; currentdirection reverses every 1/2 cycle

Time

Conductivity and the IACS

Conductivity of a metal is usually expressed as a percentage (%) and is based on the international annealed copper standard (IACS).

A specific grade of high purity copper was designated as 100 % conductivity. All other metals (except silver) are designated some % less then 100 %. These percentages indicate the relative efficiencies of the various metals for carrying electric current.

Right Hand Rule

An easy method for finding the direction of an electrically induced magnetic field is to imagine grasping the conductor in the right hand with the thumb pointing in the direction of the current flow. The fingers will then point in the direction of the lines of force. This is the right hand rule and is shown below. From this figure it can be seen that the current flow in the conductor creates circular lines of force.

(+)

(-) CURRENT FLOW

The coil's magnetic field intensity (strength) decreases with increasing distance away from the outside of the coil.

The coil's field intensity (strength) is assumed to be constant across the inside diameter of the coil. This assumption is based on the use of AC and small diameter coils, and for all practical purposes the assumption is valid.

The coil's magnetic field can be viewed as a distribution of lines of force around the coil. These lines of force are call magnetic flux, and represent the coil's magnetic force (symbol 'H').

When a metal rod is placed inside the coil, the coil flux passes through the rod. The number of lines of force in the rod divided by the cross-sectional area of the rod equals the flux density (symbol 'B') in the rod. The flux density in the rod depends on the metal's willingness to carry the magnetic flux. The metal's willingness to carry these magnetic flux lines is called permeability. The symbol for permeability is 'µ ' (mu).

The field intensity at point C is less than at point B, and point B's intensity is less than point A's

ACA

BC

AC

AC

Lines ofForce

Currentin

Currentout

Mathematically, permeability is expressed as the flux density in the material (B) divided by the magnetizing force (H) that caused it.

Like conductivity, permeability is a material property that is the same for all samples of a particular material (assume same chemistry, etc.).

example: µ for air = 1µ for copper alloys = 1µ for steels = several thousand

The permeability value of 1 for air and copper alloys (and all other non-magnetic materials) means that the magnetic flux in the material is exactly equal to the flux coming from the coil.

stated another way: b/h = 1 only when b = h

The high permeability value of steels (and all other ferromagnetic metals) means that the magnetic flux in the metal is thousands of times greater than the applied flux from the coil.

stated another way: b/h = 2000 means bflux = 2000 x hflux

Magnetic Domains

Obviously, something is happening in the ferromagnetic metals to create all this additional flux that is not happening in the non-magnetic materials. Magnetic domains are groups of atoms within a ferromagnetic metal which behave like tiny permanent magnets.

Permeability = B H

or µ =

µ =

Flux densityMagnetizing force

H

B

Partially Oriented Domains

Completely Oriented Domains (saturation)

Randomly Oriented Domains

In unmagnetized magnetic materials, the domains are randomly oriented and neutralize each other, producing no observable magnetic flux in the metal.

When the magnetizing force from the coil, is applied, the domains begin to align in the direction of the applied flux. Their combined individual magnetism starts to produce an observable increase in the flux in the metal, over and above the applied flux (H).

When the domains are completely aligned, the metal is said to be saturated, and the flux 'B' is many thousands of times greater than the applied flux 'H'. This domain behavior is responsible for the non-linear relationship between (B) and (H) in ferromagnetic metals and for the hysteresis effect.

When a coil of wire carrying alternating current is brought into proximity to a conducting article. The alternating magnetic field that surrounds the coil will penetrate the article, generating small circulating electrical currents, called eddy currents, in an article.

Eddy currents are circulating electrical currents induced in an isolated conductor by an alternating magnetic field. Note that there is no direct electrical contact between the coil and the test article - eddy currents are generated by electromagnetic induction.

Electrical current

Test coil

Article being tested

Generator

Eddy currents

Note: When a generator’s electrical current reverses it direction, the direction of the eddy currents will also reverse.

The "primary" magnetic field surrounding the ac coil will penetrate the test articles and induce eddy currents in the article. The circulating eddy currents possess their own "secondary" magnetic field. This secondary field will oppose the coils and reduce the size and strength of the coil’s field.

AC Indicator

Direction of coil’s field

Eddy current field opposes coil’s field

Changes in the strength or shape of the secondary field will affect the primary field, which will affect the AC flowing in the coil, where it will be sensed.

In this way, variations of the test article that disturb or alter the flow of the eddy currents will disturb the electromagnetic coupling between the two fields and cause indications on the test instrument

Characteristics of Eddy Current

1) Can only be induced in conductors

Coated (i.e. painted) articles may be tested, since the coils field will pass through the nonconducting coating and generate eddy currents in the metal beneath.

Plated articles should not be tested, since the coil's field will generate eddy currents in both the metallic plating and the base material. Consequently, ET indications could originate from either the base metal or the plating, confusing the inspection.

2) Can be generated only by an alternating magnetic field - there must be relative motion between the field and the test article. A DC field will not generate eddy currents. The moving AC field which builds up, then breaks down and reverses direction every 1/2 cycle, is essential to the production of eddy currents.

3) Eddy currents flow in circular paths, parallel to the coil windings.

Changes inconductivity

Change inmeter reading

Change in coil’s impedance

Change in coil’s magnetic field

Test circuit

Material

Nonconductive material

Conductive material

Conductive material

Conductive material

Depth of Penetration

Eddy currents are strongest at the surface nearest the coil (due to skin effect) and weaken with depth. The depth of eddy current penetration below the surface is directly affected by the nearness of the coil to the test article, the operating frequency, and the test article conductivity and permeability.

(A) Coil position - since the coil's field is limited in size and decreases in strength with increasing distance away from the coil, maximum field penetration into the article and, therefore, maximum depth of eddy current penetration is achieved by moving the coil as close as practical to the test article surface.

(B) Operating frequency - a relationship also exists between the frequency of the ac applies to the test coil and the eddy current depth of penetration. As the frequency is increased, eddy current distribution concentrates near the surface and decreases deep with the test article. The reverse is also true. As the frequency is lowered, the eddy current distribution extends deeper into the article.

In both view A and B above, the material and the test coil are the same. Since view a shows deeper eddy current penetration into the material, this means that a lower frequency was used. View B shows shallower penetration, so a high frequency was used. Keep in mind that a high frequency causes the eddy currents to accumulate near the surface closest to the test coil.

Coil far away from article being tested

Coil as close as possible to the article being tested

Frequency

View A

Coil

Depth of Eddy Current Penetration

Frequency

View B

Coil


c) Conductivity - the figure below illustrates that the depth of eddy current penetration also varies with metal's electrical conductivity. As conductivity increases, the depth of eddy currents decreases.

In the figure, the coil and test frequency are the same in each view. Only the material type is different. You can verify that tin is more conductive the lead, and that copper is much more conductive than either, by referring to the % IACS conductivity chart shown earlier. As the figure shows, the less conductive metals achieve deeper eddy current penetration than the more conductive metals.

d) Magnetic permeability - finally, a metal's magnetic permeability (µ) affects the depth of eddy current penetration. The depth of penetration decrease as the permeability increases. There are 3 basic types of eddy current test: surface , encircling , and inside. A surface coil is designed to be used on localized areas on a surface, and is usually contained in a hand-held probe.

An encircling coil, on the other hand, is large enough to surround an object about one of its axes and is designed to test an entire segment of the object at one time.

Indicator

Lead

Coil


Indicator

Coil


Indicator

Coil


CopperTin

An inside coil is designed to be placed inside a hole or cavity in the object, and is especially suited for testing thin wall tubing.

Note that with each of the coil types:- The eddy currents circulate parallel to the coil windings- The eddy currents hug the surface that is nearest the coil

Each of these 3 coil types may be used in either the differential or absolute test mode.

In the differential coil arrangement, two side-by-side coils are wound and connected so that the output of on cancels the output of the other as long as the test object properties are the same under both coils. This mode is most sensitive to small defects and is relatively insensitive to material variations such as hardness, gross surface irregularities, etc.

In the absolute mode, a single coil tests the area of the test object beneath it without comparison to a reference area. This mode is most sensitive to large defects longer than the coil, and to material variations such as hardness, gross surface irregularities, etc.

The 3 general material variables (properties) that affect the flow of eddy currents in the material are:

1) Changes in conductivity - conductivity changes may be caused by variations in alloy chemistry or heat treatment, or may be due to the presence of defects. Since cracks or other discontinuities force the eddy currents to take a longer path by flowing around them, the overall effect of the discontinuity is to reduce the conductivity of the metal.

As the figure illustrates, the eddy currents must flow around the crack, effectively reducing the conductivity of the metal.

2) The second material variable affecting eddy current flow is magnetic permeability. Eddy currents are induced by flux changes in the metal and are directly related to the density or amount of flux. Since changes in permeability cause changes in the amount of flux in the metal, they also cause a pronounced (and detectable) change in the eddy current flow.

3) Changes in the physical dimensions, or size and shape of the test object also affect the eddy current flow. Although the figure below is a gross example, it clearly illustrates how a change in physical dimension can alter the electromagnetic coupling between the coil and the object.

Two more dimensional of eddy current testing is edge effect and lift-off.

Edge effect is the false indication caused by disruption of by disruption of the eddy current path when the coil approaches an end or edge of the material.

The effect is strong enough to "mask' any changes due to other factors. In effect, the edge of the material looks like a very large crack to the eddy current instrument.

On the other hand, the false indication caused by changing the spacing between the test coil and the material surface is called lift-off.

Lift-off has a very large effect on the ET output display due to the decrease in primary field flux in the material as the coil distance from the materials surface is increased.

The lift-off effect can be used to measure the thickness of non-conducting coatings, such as paint, on a conducting object.

Since eddy currents cannot be generated in the non-conductor, a coil placed in contact with the painted surface "sees" the paint thickness simply as lift-off distance.

Another important relationship between eddy current flow and the presence of discontinuities is that the discontinuity must lie perpendicular to the direction of eddy current flow to be detected.

In the situation above, a surface coil passes over a surface crack and a subsurface lamination in the metal. It is easy to see that the crack will force the eddy currents to take a longer path around it, causing a detectable disruption in their flow. The lamination on the other hand, will not cause much disruption of the eddy current path since the metal separation lies parallel to the direction of current flow.

Limitations of Eddy Current Testing

1. Inspect only conducting articles (i.e. metals).

2. Can locate only surface and shallow subsurface discontinuities; inspection depth is limited to less then 1 inch.

3. Separation of the effects of conductivity, permeability, and dimension variables is difficult and often not possible.

4. ET is an indirect inspection requiring the use of calibration standards; you must know what you are looking for in order to find it.

Advantages of Eddy Current Testing

1. Able to inspect through non-conductive coatings (i.e. paint).

2. Fast, real-time inspection.

3. Totally nondestructive; no interference with the test item.

Summary of Properties of Eddy Currents

1. Generated by an alternating magnetic field.

2. Flow only in conductors.

3. Circulates parallel to coil windings.

4. Eddy current flow is affected by changes in the material's conductivity, dimension, magnetic permeability.

5. Limited to surface/shallow subsurface testing.

6. Depth of penetration is affected by conductivity and permeability of test object, by test frequency, and by nearness of the coil to the test object.

7. Able to test through surface coatings (nonconducting) but not through plating (metal).

Eddy Current Relationship of Properties

Penetration Frequency Conductivity PermeabilityDecrease Increase Increase IncreaseIncrease Decrease Decrease Decrease

Chapter 7 - Radiographic Inspection

Common Definitions and Examples

Absorbed doseThe amount of energy imparted to matter by an ionizing particle per unit mass of irradiated material at the

place of interest. It is expressed in “rads.”

AcceleratorA device that accelerates charged atomic particles to high energies. An x-ray machine is an accelerator.

ActivityA measure of how radioactive a particular radioisotope is. The number of atoms decaying per unit of time

calculates activation. Its unit of measurement is the “curie.”

Alpha particleA positively charged particle emitted by certain radioactive materials. It is made up of two neutrons and

two protons; hence it is identical with the nucleus of a helium atom.

Alpha rayA stream of fast-moving helium nuclei (alpha particles). This radiation is strongly ionizing with very weak

penetration.

AngstromA unit of length used to express wavelength. One angstrom equals 10-8 centimeters.

Anode (target side)The positive terminal of an x-ray tube. It is a high melting point element that receives the electron

bombardment from the cathode (filament).

AtomThe smallest part of an element. The atom consists of a nucleus composed, with the exception of hydrogen,

of a number of protons and neutrons. Included in the atom is an extranuclear portion composed of electrons equal in number to the protons in the nucleus. The hydrogen atom includes a nucleus of one proton and extranuclear portion of one electron.

AutotransformerA special type of transformer in which the output voltage can be easily varied. The autotransformer is

employed to adjust the primary voltage applied to the step-up transformer that produces the high voltage applied to the x-ray tube.

Background radiationThe radiation of man’s radiation natural environment, consisting of radiation that comes from cosmic rays

and from the naturally radioactive elements of the earth, including radiation from within man’s body. The term may also mean radiation extraneous to an experiment.

BackscatterRadiation scattered from the floor, walls, equipment, and other items in the area of a radiation source.

Backscatter includes secondary radiation resulting from the interaction between the primary radiation from the source and the material being radiated.

Beta particleAn electron or position emitted from a nucleus during radioactive decay.

BremsstrahlungElectromagnetic radiation (photon) emitted by charged particles when they are slowed down by electric

fields in their passage through matter. Literally means, “braking radiation” in German.

CassetteA lightproof container, which may or may not contain intensifying and/or filter screens, that is used for

holding the radiographic films in position during the radiographic exposure.

Cathode (filament side)The negatively-biased electrode of the x-ray tube.

CollimatorA device used to surround a radiation source and so constructed as to both minimize the scattered radiation

and to direct the primary or useful radiation into a more or less parallel beam onto a localized area.

Compton EffectThe glancing collision of an x-ray or gamma ray with an electron to an orbital electron in matter with a

lower energy in matter with a lower energy photon scattered at an angle to the original photon path. The electron does not absorb all of the energy.

High energy Photon

Ejected electron

Photon continues with

less energy

400 Kev Electron

200 Kev Electron Leaving

200 Kev X-Ray

Contrast (film)The change in density recorded on the film that results from a given change in radiation input. Contrast is

determined from the slope of the characteristic curve.

Contrast (radiographic)The measure of difference in the film blackening resulting from various x-ray intensities transmitted

through the object and recorded as density differences in the image. Thus, difference in film blackening from one area to another is contrast.

Contrast (subject)The ratio of radiation intensities passing through selected portions of a specimen.

DefinitionThe measure of sharpness in the outline of the image of an object recorded on film; the sharpness is the

function of the types of screens, exposure geometry, radiation energy and film characteristic.

DensitometerAn instrument utilizing the photoelectric principle to determine the degree of darkening of developed

photographic film.

DeveloperA chemical solution that reduces exposed silver halide crystals to metallic silver.

DoseThe amount of ionizing radiation energy absorbed per unit mass of irradiated material at a specific location,

such as a part of the human body.

Dose rateThe radiation dose delivered per unit time and measured, for instance, in rems per hour.

DosimeterA device that measures radiation dose, such as a film badge or ionization chamber.

Duty cycleUsually expressed in a percentage to represent the time used versus the time not used.

Electromagnetic SpectrumRepresents the electromagnetic waves of different wave lengths. The lines are not definite boundaries but

rather phase into one another.

X-RAYS AND

GAMMA RAYS

ULTRAVIOLET RAYS

LIGHT RAYS

INFRARED RAYS

RADAR WAVES

SHORT WAVE RADIO

LONG WAVE RADIO

DECREASING WAVELENGTH INCREASING

INCREASING FREQUENCY DECREASING

INCREASING ENERGY DECREASING

Electron voltIs an amount of energy equal to the energy gained by one electron when it is accelerated by one volt.

EmulsionA gelatin and silver bromide crystal mixture coated onto a transparent film base.

EncapsulationThe process of sealing radioactive materials to prevent contamination.

FilamentA piece of wire in the cathode side, negative side, of the x-ray tube used to produce electrons when heated.

FilmSpecialized film used for radiographic purposes. The components of the film are two protective layers, two

emulsion layers, and one acetate base layer.

Film badgeA package of photographic film worn as a badge by workers in the nuclear industry to measure exposure to

ionization radiation. The absorbed dose can be calculated by the degree of film darkening caused by the irradiation.

FilterA layer of absorptive material that is placed in the beam of radiation for the purpose of absorbing rays of

certain wavelengths and thus controlling the quality of the radiograph.

FixerA chemical solution that dissolves unexposed silver halide crystals from developed film emulsions.

Fog A darkening of the film resulting from chemical action of the developer, aging, scattered or secondary

radiation, pre-exposure to radiation, or exposure to visible light.

Geiger counterA radiation detection and measuring instrument. It contains a gas-filled tube that discharges electrically

when ionizing radiation passes through it. Discharges are counted to measure the radiation’s intensity.

GraininessA film characteristic that consists of the grouping or clumping together of the countless small silver grains

into relatively large masses visible to the naked eye or with slight magnification.

Half-lifeThe time in which half the atoms in a radioactive substance decay. Time is dependant upon the element.

Half-life (biological)The time required for a biological system, such as a man or an animal, to eliminate, by natural processes,

half the amount of a substance that has entered it.

protectivelayers

acetatebase

emulsion(image layer)

Half-value layerThe thickness of a material required to absorb one half of the impinging radiation.

Intensifying screenA layer of material placed in contact with the film to increase the effect of the radiation, thereby shortening

the exposure.

InterlockA device for precluding access to an area of radiation hazard either by preventing entry or by automatically

removing the hazard.

IonA charged atom or molecularly-bound group of atoms; sometimes also a free electron or other charged

subatomic particles.

Ion pairsA positive ion and a negative ion, or electron, having charges of the same magnitude and formed from a

neutral atom or molecule by the action of radiation or by any other agency that supplies energy.

IonizationThe process of adding electrons to, or knocking electrons from, atoms or molecules thereby creating ions.

High temperatures, electrical discharges, and nuclear radiation can cause ionization.

Ionization chamberAn instrument that detects and measures ionizing radiation by observing the electrical current created when

radiation ionizes gas in the chamber making the gas a conductor of electricity.

Ionizing radiationAny radiation that directly or indirectly displaces electrons from the orbital shells of atoms.

KevThe energy of X-rays or gamma rays measured in thousand electron volts.

Latent imageThe potential image that is stored in the form of chemical changes in the film emulsion and is brought out

by development of the film.

LatitudeLatitude most closely aligned with contrast is commonly called the scale of the film. Latitude is the range

of thickness of material that can be transferred or recorded on the radiograph within the useful reading range of film density. A high contrast film has little latitude and conversely a low contrast film has great latitude.

Leak testA test on sealed sources to assure that radioactive material is not being released.

Licensed materialSource material, special nuclear material, or by-product material received, possessed, used, or transferred

under a general or special license issued by the Nuclear Regulatory Commission.

MevThe energy of X-rays or gamma rays measured in million electron volts.

MicroshrinkageCracks that appear as dark feathery streaks, or irregular patches, that indicate cavities in the grain

boundaries.

Monochromatic radiationA rare condition, hypothetical, in which all gamma rays or x-rays produced are of the same wavelength.

Pair productionThe transformation of a high-energy ray into pair of particles (an electron and a positron) during its passage

through matter.

ParticleA minute constituent of matter with a measurable mass, such as a neutron, proton, or meson.

PenetrameterA small strip of material of the same

composition as the specimen being tested. Its thicknessrepresents a percentage of the specimen thickness.When placed in the path of the rays, its image on the radiograph provides a check on the radiographic techniqueemployed.

PenumbraThe shadow cast when the incident radiation is partly, but not wholly, cut off by an intervening body; the

space of partial illumination between the umbra, or perfect shadow, on all sides and the full light.

Photoelectric effectThis process involves the complete absorption of the photon during the process of knocking an electron out

of orbit. It occurs primarily with lower energy X-rays photons of 10 Kev to 500 Kev.

Approaching Photon

PhotonA discrete quantity of electromagnetic energy. Photons have no momentum but no mass or electrical

charge.

Photon absorbed

Charged atom (positive atom)

Ejected electron (negative ion)

T = thickness4T DIA T DIA 2T DIA

T

PositronA fundamental atomic particle having a mass equal to that of the electron and possessing a positive charge

equal to the negative charge of the electron.

RoentgenA unit of exposure dose of ionizing radiation. It is that amount of gamma or x-rays required to produce ions

carrying 1 electrostatic unit of electrical charge in one cubic centimeter of dry air under standard conditions.

SafelightA special lamp used in the darkroom to provide working visibility without affecting the photosensitive

emulsion of the radiographic film.

ScatterSecondary radiation that is emitted in all directions.

ScreensMetallic or fluorescent sheets used to intensify the radiation effects on films.

SensitivityA term usually referring to the ability of the radiographic procedure to detect discontinuities.

Specific activityTotal radioactivity of a given isotope per gram of element.

Source-film-distanceThe distance between the focal spot of an x-ray tube or radiation source and the film; generally expressed

in inches.

TargetThe piece of material, usually tungsten, embedded in the anode side, positive side, of the x-ray tube. A

effective and efficient target has the following four properties high atomic number, high melting point, high thermal conductivity, and low vapor pressure.

Two-film techniqueA procedure wherein two films of different relative speeds are used simultaneously to radiograph both the

thick and the thin sections of an item.

Structure of the Atom and an Element

Proton – A heavy atomic particle with a positive charge.Neutron – Close to the same weight and size of the proton with a neutral charge.Electron – A negative charged particle weighing about 1/1840th of a proton or a neutron.

Nucleus – The proton(s) and neutron(s) are group here in the center of the atom.Atomic number “Z” – This number represents the number of protons in the atom.Mass number “A” – This number represent the number of protons and neutrons in the atom.

E = element symbolZ = atomic numberA = mass number

Components of an Isotope

Isotope – One or more of the same element having the same number of protons but not the same number of neutrons.Natural isotopes – Those that occur naturally.Artificial isotope – Those elements that are created by bombarding with swarms of neutrons.Activation – This is the process of creating artificial isotopes.Stable isotopes – Atoms that are not radioactive.Unstable isotopes – Atoms that are radioactive.

Characteristics of A Radioactive Element

During the decay or disintegration process tiny particles of energy are emitted in the form of particles and waves from the nucleus.

Alpha particles (α) – The biggest and heaviest of the radiation particles and is composed of two protons and two neutrons.Beta particles (β) – A very light particle, actually a high-speed electron.Gamma rays (γ) – A form of energy that is a wave not a particle.

Two Types of Radiation

Gamma radiation – A product of nuclear disintegration or decay of radioactive elements.

X-rays – An artificial produced wave from a high voltage electron tube.1) Soft x-rays – low energy.2) Hard x-rays – high energy.

Helium Atom EZA

History of Radiography

X-rays were discovered in 1895 by Wilhelm Conrad Roentgen (1845-1923) who was a Professor at Wuerzburg University in Germany. Working with a cathode-ray tube in his laboratory, Roentgen observed a fluorescent glow of crystals on a table near his tube. The tube that Roentgen was working with consisted of a glass envelope (bulb) with electrically positive and negative electrodes encapsulated in it. The tube was evacuated of air, and when a high voltage was applied to it, the tube would produce a fluorescent glow. Roentgen shielded the tube with heavy black paper, and found that a green colored fluorescent light could be seen from a screen setting a few feet away from the tube. He concluded that a new type of ray emitted from the tube. This ray was capable of passing through the heavy paper covering. He also found that the new ray would pass through most substances casting shadows of solid objects. In his discovery, Roentgen found that the ray would pass through the tissue of humans leaving the bones and metals visible. One of Roentgen's first experiments late in 1895 was a film of his wife, Bertha's hand with a ring on. However, it can be argued that the first use of X-rays was for an industrial (not medical) application as Roentgen produced a radiograph of a set of weights in a box to show his colleagues.

Roentgen's discovery was a scientific bombshell, and was received with extraordinary interest by both scientist and laymen. Scientists everywhere could duplicate his experiment because the cathode tube was very well known during this period. Many scientist dropped other lines of research to pursue the mysterious rays, and the newspapers and magazines of the day provided the public with numerous stories, some true, others fanciful, about the properties of the newly discovered rays. The public fancy was caught by the invisible ray with the ability to pass through solid matter, and, in conjunction with a photographic plate, provide a picture, albeit a shadowy diffuse one, of the bones and interior of the body. Scientific fancy was captured by an extraordinary new radiation, of shorter wavelength than light, that presaged new and great vistas in physics, and the structure of matter. Both the scientist and the public were enthusiastic about potential applications of the newly discovered rays as an aid in medicine and surgery. Thus, within a month after the

announcement of the discovery, several medical radiographs had been made in Europe and the United States that were used by surgeons to guide them in their work. In June 1896, only 6 months after Roentgen announced his discovery, X-rays were being used by battlefield physicians to locate bullets in wounded soldiers.

Prior to 1912, X-rays were used little outside the realms of medicine, and dentistry, though some X-ray pictures of metals were produced. The main reason that were not used in industrial application before this date was because the X-ray tubes (the source of the X-rays) of that period broke down under the voltages required to produce rays of satisfactory penetrating power for industrial purpose. However, that changed in 1913 when the high vacuum X-ray tubes designed by Coolidge became available. The high vacuum tubes were an intense and reliable X-ray sources, operating at energies up to 100,000 volts. In 1922, industrial radiography took another step forward with the advent of the 200,000-volt X-ray tube that allowed radiographs of three inches thick steel parts to be produced in a reasonable amount of time. In 1931, General Electric Company developed 1000, 000 volt X-ray generators. That same year, the American Society of Mechanical Engineers (ASME) permitted X-ray approval of fusion welded pressure vessels.

Shortly after the discovery of X-rays, another form of penetrating rays was discovered. In 1896, French scientist Henri Becquerel discovered radioactivity somewhat by accident, like many other great scientific discoveries. Many of the scientists of the period were working with cathode rays, and other scientists were gathering evidence on the theory that the atom could be subdivided. Some of this new evidence showed that certain types of atoms disintegrate by themselves. It was Henri Becquerel who discovered this phenomenon while investigating the properties of fluorescent minerals. Becquerel was working on the principles of fluorescence, certain minerals glow (fluoresce) when exposed to sunlight. He utilized photographic plates to record this fluorescence.

One of the minerals Becquerel worked with was a uranium compound. On a day when it was too cloudy to expose his samples to direct sunlight, Becquerel stored some of the compound in a drawer with photographic plates. When he developed these plates a couple of days later, he discovered that they were fogged. Becquerel questioned what would have caused this fogging. He knew he had wrapped the plates tightly before using them, so the fogging was not due to stray light. In addition, he noticed that only the plates that were in the drawer with the uranium compound were fogged. Becquerel concluded that the uranium compound gave off a type of radiation that could penetrate heavy paper and affect photographic film. Becquerel continued to test many samples of uranium compounds and determined that the source of radiation was the element uranium. At this time, enough information was gathered to determine that an element, which gives off radiation, is said to be radioactive, and possesses the property of radioactivity. Becquerel's discovery was, unlike that of the X-rays, virtually unnoted by the layman and scientist alike. Only a relatively few scientist were interested in Becquerel's findings, and it was not until the discovery of radium by the Curies two years later that interest in radioactivity became wide spread.

While working in France at the time of Becquerel's discovery, Polish scientist Marie Curie became very interested in his work. She too, suspected that a uranium ore known as pitchblende contained other radioactive elements. Marie and her husband, a French scientist, Pierre Curie started looking for these other elements. In 1898, the Curies discovered another radioactive element in pitchblende; they named it `polonium' in honor of Marie Curie's native homeland. Later that same year, the Curie's discovered another radioactive element for which they named `radium', or shining element. Both polonium and radium are more radioactive than uranium. Since these discoveries, many other radioactive elements have been discovered or produced.

The initial gamma ray source was radium, which allows radiography of castings up to 10 to 12 inches thick. During World War II, industrial radiography grew tremendously as part of the Navy's shipbuilding program. Shortly after the war, manmade gamma ray sources such as cobalt and iridium became available in 1946. These new sources were far stronger than radium sources and were less expensive. Thus the manmade sources rapidly replaced radium, and the use of gamma rays grew quickly in industrial radiography.

60° Coverage for Pipes and Location Marker Measurements

1/2" 0.840 2.638 0.440 0.528 0.440 0.377 0.330 0.293 0.264 0.240 0.2203/4" 1.050 3.299 0.550 0.660 0.550 0.471 0.412 0.367 0.330 0.300 0.2751" 1.315 4.131 0.689 0.826 0.689 0.590 0.516 0.459 0.413 0.376 0.344

1-1/4" 1.660 5.215 0.869 1.043 0.869 0.745 0.652 0.579 0.522 0.474 0.4351-1/2" 1.900 5.969 0.995 1.194 0.995 0.853 0.746 0.663 0.597 0.543 0.497

2" 2.375 7.461 1.244 1.492 1.244 1.066 0.933 0.829 0.746 0.678 0.6222-1/2" 2.875 9.032 1.505 1.806 1.505 1.290 1.129 1.004 0.903 0.821 0.753

3" 3.500 10.996 1.833 2.199 1.833 1.571 1.374 1.222 1.100 1.000 0.9163-1/2" 4.000 12.566 2.094 2.513 2.094 1.795 1.571 1.396 1.257 1.142 1.047

4" 4.500 14.137 2.356 2.827 2.356 2.020 1.767 1.571 1.414 1.285 1.1785" 5.563 17.477 2.913 3.495 2.913 2.497 2.185 1.942 1.748 1.589 1.4566" 6.625 20.813 3.469 4.163 3.469 2.973 2.602 2.313 2.081 1.892 1.7348" 8.625 27.096 4.516 5.419 4.516 3.871 3.387 3.011 2.710 2.463 2.258

1/2" 0.840 2.638 0.440 0.203 0.188 0.176 0.165 0.155 0.147 0.139 0.1323/4" 1.050 3.299 0.550 0.254 0.236 0.220 0.206 0.194 0.183 0.174 0.1651" 1.315 4.131 0.689 0.318 0.295 0.275 0.258 0.243 0.230 0.217 0.207

1-1/4" 1.660 5.215 0.869 0.401 0.373 0.348 0.326 0.307 0.290 0.274 0.2611-1/2" 1.900 5.969 0.995 0.459 0.426 0.398 0.373 0.351 0.332 0.314 0.298

2" 2.375 7.461 1.244 0.574 0.533 0.497 0.466 0.439 0.415 0.393 0.3732-1/2" 2.875 9.032 1.505 0.695 0.645 0.602 0.565 0.531 0.502 0.475 0.452

3" 3.500 10.996 1.833 0.846 0.785 0.733 0.687 0.647 0.611 0.579 0.5503-1/2" 4.000 12.566 2.094 0.967 0.898 0.838 0.785 0.739 0.698 0.661 0.628

4" 4.500 14.137 2.356 1.087 1.010 0.942 0.884 0.832 0.785 0.744 0.7075" 5.563 17.477 2.913 1.344 1.248 1.165 1.092 1.028 0.971 0.920 0.8746" 6.625 20.813 3.469 1.601 1.487 1.388 1.301 1.224 1.156 1.095 1.0418" 8.625 27.096 4.516 2.084 1.935 1.806 1.694 1.594 1.505 1.426 1.355

6 7 8 9

NPSOutside

DiameterCircumference (OD times pi)

60° Coverage

13 14 15 16 17 18 19 20

General Information

10 11 12

Distance Between Location Markers (centerline)

NPSOutside

DiameterCircumference (OD times pi)

60° Coverage

5

Common Math Formulas

I1(D1) 2 = I2(D2) 2

I (D ) I )D = I =

I

I )I (D ) I =

D =I

1 1

2 2

2 2 2(D

2

1 (D1

)2

2

2 1(D

1

I=Intensity D=Distance

(D2

)2

1 1 2

2

2

Ma1(SFD 2) 2 = Ma2(SFD 1) 2

Ma (SFD ) Ma )SFD = Ma =

Ma

Ma )Ma (SFD ) Ma =

SFD =Ma

2 1

2 2

2 1 2(SFD

1

12

)(SFD2

2

2 1(SFD

2

Ma=Milliamperage SFD=Source to film distance

(SFD1

)2

1 2 2

1

2

Ci1(SFD 2) 2 = Ci2(SFD 1) 2

Ci (SFD ) Ci )SFD = Ci =

Ci

Ci )Ci (SFD ) Ci =

SFD =Ci

Ci=Curie SFD=Source to film distance

(SFD1

)2

1 2 2

1

2

2

2 1(SFD

2

2)(SFD

22 1

2 2

2 1 2(SFD

1

1

Ef1(SFD 2) 2 = Ef2(SFD 1) 2

Ef (SFD ) Ef )SFD = Ef =

Ef

Ef )Ef (SFD ) Ef =

SFD =Ef

Ef=Exposure factor SFD=Source to film distance

(SFD1

)2

1 2 2

1

2

2

2

2 1(SFD

2

12

)(SFD

2 2

2 1 2(SFD

1

2 1

T1(SFD 2) 2 = T2(SFD 1) 2

T (SFD ) T )SFD = T =

T

T )T (SFD ) T =

SFD =T

2 1

2 2

2 1 2(SFD

1

12

)(SFD2

2

2 1(SFD

2

T=Time SFD=Source to film distance

(SFD1

)2

1 2 2

1

2

OF1(SFD 2) 2 = OF2(SFD 1) 2

OF (SFD ) OF )SFD = OF =

OF

OF )OF (SFD ) OF =

SFD =OF

OF=Offset SFD=Source to film distance

(SFD1

)2

1 2 2

1

2

2

2 1(SFD

2

2)(SFD

22 1

2 2

2 1 2(SFD

1

1

(TS + GAP) TS

Ma1 ( T1) = Ma2 ( T2) Dn1 ( Ma2) = Dn2 ( Ma1)

Ci1 ( T1) = Ci2 ( T2) Dn1 ( Ci2) = Dn2 ( Ci1)

Dn1 ( Ef2) = Dn2 ( Ef1) Dn1 ( T2) = Dn2 ( T1)

FSS = IS - (2 X PHS)

PHS=Pin hole size

Ma=Milliamperage T=Time

Ci=Curie T=Time

Dn=Density Ef=Exposure factor Dn=Density T=Time

Dn=Density Ma=Milliamperage

Dn=Density Ci=Curie

FSS=Focal spot size IS=Image size

SFD=Source to film distanceGAP=Film to specimen distance

DS=Defect shiftMS=Marker shift

TS(TM)=Thickness (TM if location marker is on TM)TS=Depends on technique used

X old SFD = new SFD(TM or TS) X DS

MS

Adding / Removing Shielding

I o

2 HVL

I =Io = Original intensity

= # of Half-value layers added

Intensity after adding shielding

HVL

I =

Determining Shielding Required Common Half-Value Layers for IR192

Concrete 1.75”Steel .500”Lead .190”Tungsten .130”

Kodak Radiographic Films

Type Speed Grain

R 8 Ultra fine Decay Formula M 4 Extra fine

T 2 Extra fine AA 1 Fine

Gamma Radiation Exposure Calculator Experienced Based Roentgen Factors (Steel)

D E N S I T YF 1.0 1.5 2.0 2.5 3.0 4.0I AA .652 .730 1.0 1.25 1.55 2.4L T 1.3 1.46 2.0 2.5 3.1 4.8

M M 2.6 2.92 4.0 5.5 6.2 9.6

)

I =Io = Original intensity

= # of Half-value layers added

Intensity after removing shielding

HVL

Io(2

HVLI =

IoI

Io = Original intensityI = Desired intensity

HVL.693

HVL = # of HVL's required to reduce intensityln = Natural logrithm

( )ln=

2 n

n = T/HLT = Time passed since known activity passed

HL = Half-life of the isotope

AoA =

Ao = Original known activityA = New activity

Magic Circles

Single Wall Exposure / Single Wall Viewing for Plate

Source

Penny

Backing Strap Shim

Ts Tm

Weld

Pb "B"

TM = DESIGN MATERIAL THICKNESSPENNY = BASED ON Tm

SHIM = BASED ON (1) WELD AND (1) ROOTREINFORCEMENT

SFD = BASED ON TsENERGY = BASED ON Ts

SWE / SWV (PLATE)

Film

D Ef

Ef

DR T TMa

Ci T

D=DoseDR=Dose rateT=Time

Ef=Exposure factorMa=MilliamperageT=Time

Ef=Exposure factorCi=CurieT=Time

A

CB

A = B X CB= A / CC= A / B

Single Wall Exposure / Single Wall Viewing for Pipe

Source

Penny

Weld Shim

Ts Tm

Pb "B"

Weld

TM = DESIGN MATERIAL THICKNESSPENNY = BASED ON Tm


SFD = BASED ON TsENERGY = BASED ON Ts

Backing Ring/Consumable Insert

SWE / SWV (PIPE)

Film


Double Wall Exposure / Double Wall View (superimposed)

Source

Penny

Weld Shim

Tm

T s

Ts1

Weld

Pb "B"

TM = DESIGN MATERIAL THICKNESSPENNY = BASED ON (2) Tm


SFD = BASED ON OUTSIDE ODENERGY = BASED ON (2) Tm, (2) WELD AND

(2) ROOT REINFORCEMENTS



DWE / DWV

Film

Double Wall Exposure / Double Wall View (offset)

Source

1/2 Location Penny

Weld markers Shim

Tm

T s

Ts1

1/2 Location Weld

markers

Pb "B"

TM = DESIGN MATERIAL THICKNESSPENNY = BASED ON (2) Tm


SFD = BASED ON OUTSIDE ODENERGY = BASED ON (2) Tm, (1) WELD AND

(1) ROOT REINFORCEMENT

Consumable Insert

Consumable Insert

DWE / DWV

Film

Double Wall Exposure / Single Wall View

Source

1/2 Location

markers Weld

Tm T s

Weld 1/2 Location Shim

markers Penny

Pb "B"

TM = DESIGN MATERIAL THICKNESSPENNY = BASED ON (1) Tm FILM SIDE PENNY CHART


SFD = BASED ON (1) TsENERGY = BASED ON (2) Tm, (1) WELD AND

(1) ROOT REINFORCEMENT

DWE / SWV

Film

Consumable Insert

Consumable Insert

KILLER CARL

Penetrameter Material and Group Numbers

K C L Q G S P Wi o a u r e e al n t a a n n vo t i l i s e ev r t i n i t lo a u t i t r el s d y n i a nt t e e v t ga s i i tg s t o he y n

Magnesium

XX

GROUP 03

Aluminum

XX

GROUP 02

Titianium

XX

GROUP 01

Carbon steel Alloy steel

XX

GROUP 1S-1, S-2, S-3, S-4, S-5, S-6,

Stainless steel S-7, S-8, S-10H, S-11A, S-11B,Manganesse-nickel-aluminum bronze S-11C, S-11D, S-36B, S-37A,

S-37B

Aluminum bronze

XX

GROUP 2

Nickel-aluminum-bronze

Nickel-chromium-iron alloy

XX

GROUP 3

Nickel-copper alloys

XX

GROUP 4

Copper-nickel alloys

Tin bronze Gun metals

XX

GROUP 5

Valve bronze

S-34

S-38

S-21, S-22, S-25, S-26

S-51, S-52, S-53

S-35, S-36

S-42, S-43, S-44

Penny T-Hole Maximum Density

LAIMAX

T-HOLE DENSITY

LAIMAX

T-HOLE DENSITY

LAIMAX

T-HOLE DENSITY

LAIMAX

T-HOLE DENSITY

LAIMAX

T-HOLE DENSITY

1.50 1.72 2.00 2.30 2.50 2.87 3.00 3.45 3.50 4.001.51 1.73 2.01 2.31 2.51 2.88 3.01 3.46 3.51 4.001.52 1.74 2.02 2.32 2.52 2.89 3.02 3.47 3.52 4.001.53 1.75 2.03 2.33 2.53 2.90 3.03 3.48 3.53 4.001.54 1.77 2.04 2.34 2.54 2.92 3.04 3.49 3.54 4.001.55 1.78 2.05 2.35 2.55 2.93 3.05 3.50 3.55 4.001.56 1.79 2.06 2.36 2.56 2.94 3.06 3.51 3.56 4.001.57 1.80 2.07 2.38 2.57 2.95 3.07 3.53 3.57 4.001.58 1.81 2.08 2.39 2.58 2.96 3.08 3.54 3.58 4.001.59 1.82 2.09 2.40 2.59 2.97 3.09 3.55 3.59 4.001.60 1.84 2.10 2.41 2.60 2.99 3.10 3.56 3.60 4.001.61 1.85 2.11 2.42 2.61 3.00 3.11 3.57 3.61 4.001.62 1.86 2.12 2.43 2.62 3.01 3.12 3.58 3.62 4.001.63 1.87 2.13 2.44 2.63 3.02 3.13 3.59 3.63 4.001.64 1.88 2.14 2.46 2.64 3.03 3.14 3.61 3.64 4.001.65 1.89 2.15 2.47 2.65 3.04 3.15 3.62 3.65 4.001.66 1.90 2.16 2.48 2.66 3.05 3.16 3.63 3.66 4.001.67 1.92 2.17 2.49 2.67 3.07 3.17 3.64 3.67 4.001.68 1.93 2.18 2.50 2.68 3.08 3.18 3.65 3.68 4.001.69 1.94 2.19 2.51 2.69 3.09 3.19 3.66 3.69 4.001.70 1.95 2.20 2.53 2.70 3.10 3.20 3.68 3.70 4.001.71 1.96 2.21 2.54 2.71 3.11 3.21 3.69 3.71 4.001.72 1.97 2.22 2.55 2.72 3.12 3.22 3.70 3.72 4.001.73 1.98 2.23 2.56 2.73 3.13 3.23 3.71 3.73 4.001.74 2.00 2.24 2.57 2.74 3.15 3.24 3.72 3.74 4.001.75 2.01 2.25 2.58 2.75 3.16 3.25 3.73 3.75 4.001.76 2.02 2.26 2.59 2.76 3.17 3.26 3.74 3.76 4.001.77 2.03 2.27 2.61 2.77 3.18 3.27 3.76 3.77 4.001.78 2.04 2.28 2.62 2.78 3.19 3.28 3.77 3.78 4.001.79 2.05 2.29 2.63 2.79 3.20 3.29 3.78 3.79 4.001.80 2.07 2.30 2.64 2.80 3.22 3.30 3.79 3.80 4.001.81 2.08 2.31 2.65 2.81 3.23 3.31 3.80 3.81 4.001.82 2.09 2.32 2.66 2.82 3.24 3.32 3.81 3.82 4.001.83 2.10 2.33 2.67 2.83 3.25 3.33 3.82 3.83 4.001.84 2.11 2.34 2.69 2.84 3.26 3.34 3.84 3.84 4.001.85 2.12 2.35 2.7 2.85 3.27 3.35 3.85 3.85 4.001.86 2.13 2.36 2.71 2.86 3.28 3.36 3.86 3.86 4.001.87 2.15 2.37 2.72 2.87 3.30 3.37 3.87 3.87 4.001.88 2.16 2.38 2.73 2.88 3.31 3.38 3.88 3.88 4.001.89 2.17 2.39 2.74 2.89 3.32 3.39 3.89 3.89 4.001.90 2.18 2.40 2.76 2.90 3.33 3.40 3.91 3.90 4.001.91 2.19 2.41 2.77 2.91 3.34 3.41 3.92 3.91 4.001.92 2.20 2.42 2.78 2.92 3.35 3.42 3.93 3.92 4.001.93 2.21 2.43 2.79 2.93 3.36 3.43 3.94 3.93 4.001.94 2.23 2.44 2.80 2.94 3.38 3.44 3.95 3.94 4.001.95 2.24 2.45 2.81 2.95 3.39 3.45 3.96 3.95 4.001.96 2.25 2.46 2.82 2.96 3.40 3.46 3.97 3.96 4.001.97 2.26 2.47 2.84 2.97 3.41 3.47 3.99 3.97 4.001.98 2.27 2.48 2.85 2.98 3.42 3.48 4.00 3.98 4.001.99 2.28 2.49 2.86 2.99 3.43 3.49 4.00 3.99 4.002.00 2.30 2.50 2.87 3.00 3.45 3.50 4.00 4.00 4.00

LAI x 1.15 = MAX PENNY DENSITY

2% Penetrameter Quality Conversion Chart (X-RAY ONLY)

THICKNESSTHICKNESS

@ 1%

2-PENNY

EQV

THICKNESS @ 2%

2-PENNY

THICKNESS @ 4%

2-PENNY EQV

1/64 .015625 .00015625 .25 .0003125 .25 .000625 .25

1/32 .03125 .0003125 .25 .000625 .25 .00125 .25

3/64 .046875 .00046875 .25 .0009375 .25 .001875 .25

1/16 .0625 .000625 .25 .00125 .25 .0025 .25

5/64 .078125 .00078125 .25 .0015625 .25 .003125 .25

3/32 .09375 .0009375 .25 .001875 .25 .00375 .25

7/64 .109375 .00109375 .25 .0021875 .25 .004375 .25

1/8 .125 .00125 .25 .0025 .25 .005 .25

9/64 .140625 .00140625 .25 .0028125 .25 .005625 .28

5/32 .15625 .0015625 .25 .003125 .25 .00625 .31

11/64 .171875 .00171875 .25 .0034375 .25 .006875 .34

3/16 .1875 .001875 .25 .00375 .25 .0075 .37

13/64 .203125 .00203125 .25 .0040625 .25 .008125 .40

7/32 .21875 .0021875 .25 .004375 .25 .00875 .43

15/64 .234375 .00234375 .25 .0046875 .25 .009375 .46

1/4 .250 .0025 .25 .005 .25 .01 .50

17/64 .265625 .00265625 .25 .0053125 .26 .010625 .53

9/32 .28125 .0028125 .25 .005625 .28 .01125 .56

19/64 .296875 .00296875 .25 .0059375 .29 .011875 .59

5/16 .3125 .003125 .25 .00625 .31 .0125 .62

21/64 .328125 .00328125 .25 .0065625 .32 .013125 .65

11/32 .34375 .0034375 .25 .006875 .34 .01375 .68

23/64 .359375 .00359375 .25 .0071875 .35 .014375 .71

3/8 .375 .00375 .25 .0075 .37 .015 .75

25/64 .390625 .00390625 .25 .0078125 .39 .015625 .78

13/32 .40625 .0040625 .25 .008125 .40 .01625 .81

27/64 .421875 .00421875 .25 .0084375 .42 .016875 .84

7/16 .4375 .004375 .25 .00875 .43 .0175 .87

29/64 .453125 .00453125 .25 .0090625 .45 .018125 .90

15/32 .46875 .0046875 .25 .009375 .46 .01875 .93

31/64 .484375 .00484375 .25 .0096875 .48 .019375 .96

1/2 .500 .005 .25 .01 .50 .02 1.0

33/64 .515625 .00515625 .25 .0103125 .51 .020625 1.0

17/32 .53125 .0053125 .26 .010625 .53 .02125 1.0

35/64 .546875 .00546875 .27 .0109375 .54 .021875 1.0

9/16 .5625 .005625 .28 .01125 .56 .0225 1.1

37/64 .578125 .00578125 .28 .0115625 .57 .023125 1.1

19/32 .59375 .0059375 .29 .011875 .59 .02375 1.1

39/64 .609375 .00609375 .30 .0121875 .60 .024375 1.2

5/8 .625 .00625 .31 .0125 .62 .025 1.2


THICKNESSTHICKNESS

@ 1%

2-PENNY

EQV

THICKNESS @ 2%

2-PENNY

THICKNESS @ 4%

2-PENNY

EQV

41/64 .640625 .00640625 .32 .0128125 .64 .025625 1.2

21/32 .65625 .0065625 .32 .013125 .65 .02625 1.3

43/64 .671875 .00671875 .33 .0134375 .67 .026875 1.3

11/16 .6875 .006875 .34 .01375 .68 .0275 1.3

45/64 .703125 .00703125 .35 .0140625 .70 .028125 1.4

23/32 .71875 .0071875 .35 .014375 .71 .02875 1.4

47/64 .734375 .00734375 .36 .0146875 .73 .029375 1.4

3/4 .750 .0075 .37 .015 .75 .03 1.5

49/64 .765625 .00765625 .38 .0153125 .76 .030625 1.5

25/32 .78125 .0078125 .39 .015625 .78 .03125 1.5

51/64 .796875 .00796875 .39 .0159375 .79 .031875 1.5

13/16 .8125 .008125 .40 .01625 .81 .0325 1.6

53/64 .828125 .00828125 .41 .0165625 .82 .033125 1.6

27/32 .84375 .0084375 .42 .016875 .84 .03375 1.6

55/64 .859375 .00859375 .42 .0171875 .85 .034375 1.7

7/8 .875 .00875 .43 .0175 .87 .035 1.7

57/64 .890625 .00890625 .44 .0178125 .89 .035625 1.7

29/32 .90625 .0090625 .45 .018125 .90 .03625 1.8

59/64 .921875 .00921875 .46 .0184375 .92 .036875 1.8

15/16 .9375 .009375 .46 .01875 .93 .0375 1.8

61/64 .953125 .00953125 .47 .0190625 .95 .038125 1.9

31/32 .96875 .0096875 .48 .019375 .96 .03875 1.9

63/64 .984375 .00984375 .49 .0196875 .98 .039375 1.9

1 1 .01 .50 .02 1.0 .04 2.0

1- 1/64 1.015625 .01015625 .50 .0203125 1.0 .040625 2.0

1- 1/32 1.03125 .0103125 .50 .020625 1.0 .04125 2.0

1- 3/64 1.046875 .01046875 .50 .0209375 1.0 .041875 2.0

1- 1/16 1.0625 .010625 .50 .02125 1.0 .0425 2.1

1- 5/64 1.078125 .01078125 .50 .0215625 1.0 .043125 2.1

1- 3/32 1.09375 .0109375 .50 .021875 1.0 .04375 2.1

1- 7/64 1.109375 .01109375 .55 .0221875 1.1 .044375 2.2

1- 1/8 1.125 .01125 .55 .0225 1.1 .045 2.2

1- 9/64 1.140625 .01140625 .55 .0228125 1.1 .045625 2.2

1- 5/32 1.15625 .0115625 .55 .023125 1.1 .04625 2.3

1- 11/64 1.171875 .01171875 .55 .0234375 1.1 .046875 2.3

1- 3/16 1.1875 .011875 .55 .02375 1.1 .0475 2.3

1- 13/64 1.203125 .01203125 .60 .0240625 1.2 .048125 2.4

1- 7/32 1.21875 .0121875 .60 .024375 1.2 .04875 2.4

1- 15/64 1.234375 .01234375 .60 .0246875 1.2 .049375 2.4

1- 1/4 1.25 .0125 .60 .025 1.2 .05 2.5


MATERIAL THICKNESS

THICKNESS @ 1%

2-PENNY

EQV

THICKNESS @ 2%

2-PENNY

THICKNESS @ 4%

2-PENNY

EQV

1- 17/64 1.265625 .01265625 .60 .0253125 1.2 .050625 2.5

1- 9/32 1.28125 .0128125 .60 .025625 1.2 .05125 2.5

1- 19/64 1.296875 .01296875 .60 .0259375 1.2 .051875 2.5

1- 5/16 1.3125 .013125 .65 .02625 1.3 .0525 2.6

1- 21/64 1.328125 .01328125 .65 .0265625 1.3 .053125 2.6

1- 11/32 1.34375 .0134375 .65 .026875 1.3 .05375 2.6

1- 23/64 1.359375 .01359375 .65 .0271875 1.3 .054375 2.7

1- 3/8 1.375 .01375 .65 .0275 1.3 .055 2.7

1- 25/64 1.390625 .01390625 .65 .0278125 1.3 .055625 2.7

1- 13/32 1.40625 .0140625 .70 .028125 1.4 .05625 2.8

1- 27/64 1.421875 .01421875 .70 .0284375 1.4 .056875 2.8

1- 7/16 1.4375 .014375 .70 .02875 1.4 .0575 2.8

1- 29/64 1.453125 .01453125 .70 .0290625 1.4 .058125 2.9

1- 15/32 1.46875 .0146875 .70 .029375 1.4 .05875 2.9

1- 31/64 1.484375 .01484375 .70 .0296875 1.4 .059375 2.9

1- 1/2 1.5 .015 .75 .03 1.5 .06 3.0

1- 33/64 1.515625 .01515625 .75 .0303125 1.5 .060625 3.0

1- 17/32 1.53125 .0153125 .75 .030625 1.5 .06125 3.0

1- 35/64 1.546875 .01546875 .75 .0309375 1.5 .061875 3.0

1- 9/16 1.5625 .015625 .75 .03125 1.5 .0625 3.1

1- 37/64 1.578125 .01578125 .75 .0315625 1.5 .063125 3.1

1- 19/32 1.59375 .0159375 .75 .031875 1.5 .06375 3.1

1- 39/64 1.609375 .01609375 .80 .0321875 1.6 .064375 3.2

1- 5/8 1.625 .01625 .80 .0325 1.6 .065 3.2

1- 41/64 1.640625 .01640625 .80 .0328125 1.6 .065625 3.2

1- 21/32 1.65625 .0165625 .80 .033125 1.6 .06625 3.3

1- 43/64 1.671875 .01671875 .80 .0334375 1.6 .066875 3.3

1- 11/16 1.6875 .016875 .80 .03375 1.6 .0675 3.3

1- 45/64 1.703125 .01703125 .85 .0340625 1.7 .068125 3.4

1- 23/32 1.71875 .0171875 .85 .034375 1.7 .06875 3.4

1- 47/64 1.734375 .01734375 .85 .0346875 1.7 .069375 3.4

1- 3/4 1.75 .0175 .85 .035 1.7 .07 3.5

1- 49/64 1.765625 .01765625 .85 .0353125 1.7 .070625 3.5

1- 25/32 1.78125 .0178125 .85 .035625 1.7 .07125 3.5

1- 51/64 1.796875 .01796875 .85 .0359375 1.7 .071875 3.5

1- 13/16 1.8125 .018125 .90 .03625 1.8 .0725 3.6

1- 53/64 1.828125 .01828125 .90 .0365625 1.8 .073125 3.6

1- 27/32 1.84375 .0184375 .90 .036875 1.8 .07375 3.6

1- 55/64 1.859375 .01859375 .90 .0371875 1.8 .074375 3.7


MATERIAL THICKNESS

THICKNESS @ 1%

2-PENNY

EQV

THICKNESS @ 2%

2-PENNY

THICKNESS @ 4%

2-PENNY

EQV

1- 7/8 1.875 .01875 .90 .0375 1.8 .075 3.7

1- 57/64 1.890625 .01890625 .90 .0378125 1.8 .075625 3.7

1- 29/32 1.90625 .0190625 .95 .038125 1.9 .07625 3.8

1- 59/64 1.921875 .01921875 .95 .0384375 1.9 .076875 3.8

1- 15/16 1.9375 .019375 .95 .03875 1.9 .0775 3.8

1- 61/64 1.953125 .01953125 .95 .0390625 1.9 .078125 3.9

1- 31/32 1.96875 .0196875 .95 .039375 1.9 .07875 3.9

1- 63/64 1.984375 .01984375 .95 .0396875 1.9 .079375 3.9

2 2 .02 1.0 .04 2.0 .08 4.0

2- 1/64 2.015625 .02015625 1.0 .0403125 2.0 .080625 4.0

2- 1/32 2.03125 .0203125 1.0 .040625 2.0 .08125 4.0

2- 3/64 2.046875 .02046875 1.0 .0409375 2.0 .081875 4.0

2- 1/16 2.0625 .020625 1.0 .04125 2.0 .0825 4.1

2- 5/64 2.078125 .02078125 1.0 .0415625 2.0 .083125 4.1

2- 3/32 2.09375 .0209375 1.0 .041875 2.0 .08375 4.1

2- 7/64 2.109375 .02109375 1.0 .0421875 2.1 .084375 4.2

2- 1/8 2.125 .02125 1.0 .0425 2.1 .085 4.2

2- 9/64 2.140625 .02140625 1.0 .0428125 2.1 .085625 4.2

2- 5/32 2.15625 .0215625 1.0 .043125 2.1 .08625 4.3

2- 11/64 2.171875 .02171875 1.0 .0434375 2.1 .086875 4.3

2- 3/16 2.1875 .021875 1.0 .04375 2.1 .0875 4.3

2- 13/64 2.203125 .02203125 1.1 .0440625 2.2 .088125 4.4

2- 7/32 2.21875 .0221875 1.1 .044375 2.2 .08875 4.4

2- 15/64 2.234375 .02234375 1.1 .0446875 2.2 .089375 4.4

2- 1/4 2.25 .0225 1.1 .045 2.2 .09 4.5

2- 17/64 2.265625 .02265625 1.1 .0453125 2.2 .090625 4.5

2- 9/32 2.28125 .0228125 1.1 .045625 2.2 .09125 4.5

2- 19/64 2.296875 .02296875 1.1 .0459375 2.2 .091875 4.5

2- 5/16 2.3125 .023125 1.1 .04625 2.3 .0925 4.6

2- 21/64 2.328125 .02328125 1.1 .0465625 2.3 .093125 4.6

2- 11/32 2.34375 .0234375 1.1 .046875 2.3 .09375 4.6

2- 23/64 2.359375 .02359375 1.1 .0471875 2.3 .094375 4.7

2- 3/8 2.375 .02375 1.1 .0475 2.3 .095 4.7

2- 25/64 2.390625 .02390625 1.1 .0478125 2.3 .095625 4.7

2- 13/32 2.40625 .0240625 1.2 .048125 2.4 .09625 4.8

2- 27/64 2.421875 .02421875 1.2 .0484375 2.4 .096875 4.8

2- 7/16 2.4375 .024375 1.2 .04875 2.4 .0975 4.8

2- 29/64 2.453125 .02453125 1.2 .0490625 2.4 .098125 4.9

2- 15/32 2.46875 .0246875 1.2 .049375 2.4 .09875 4.9

2- 31/64 2.484375 .02484375 1.2 .0496875 2.4 .099375 4.9


MATERIAL THICKNESS

THICKNESS @ 1%

2-PENNY

EQV

THICKNESS @ 2%

2-PENNY

THICKNESS @ 4%

2-PENNY

EQV

2- 1/2 2.5 .025 1.2 .05 2.5 .1 5.0

2- 33/64 2.515625 .02515625 1.2 .0503125 2.5 .100625 5.0

2- 17/32 2.53125 .0253125 1.2 .050625 2.5 .10125 5.0

2- 35/64 2.546875 .02546875 1.2 .0509375 2.5 .101875 5.0

2- 9/16 2.5625 .025625 1.2 .05125 2.5 .1025 5.1

2- 37/64 2.578125 .02578125 1.2 .0515625 2.5 .103125 5.1

2- 19/32 2.59375 .0259375 1.2 .051875 2.5 .10375 5.1

2- 39/64 2.609375 .02609375 1.3 .0521875 2.6 .104375 5.2

2- 5/8 2.625 .02625 1.3 .0525 2.6 .105 5.2

2- 41/64 2.640625 .02640625 1.3 .0528125 2.6 .105625 5.2

2- 21/32 2.65625 .0265625 1.3 .053125 2.6 .10625 5.3

2- 43/64 2.671875 .02671875 1.3 .0534375 2.6 .106875 5.3

2- 11/16 2.6875 .026875 1.3 .05375 2.6 .1075 5.3

2- 45/64 2.703125 .02703125 1.3 .0540625 2.7 .108125 5.4

2- 23/32 2.71875 .0271875 1.3 .054375 2.7 .10875 5.4

2- 47/64 2.734375 .02734375 1.3 .0546875 2.7 .109375 5.4

2- 3/4 2.75 .0275 1.3 .055 2.7 .11 5.5

2- 49/64 2.765625 .02765625 1.3 .0553125 2.7 .110625 5.5

2- 25/32 2.78125 .0278125 1.3 .055625 2.7 .11125 5.5

2- 51/64 2.796875 .02796875 1.3 .0559375 2.7 .111875 5.5

2- 13/16 2.8125 .028125 1.4 .05625 2.8 .1125 5.6

2- 53/64 2.828125 .02828125 1.4 .0565625 2.8 .113125 5.6

2- 27/32 2.84375 .0284375 1.4 .056875 2.8 .11375 5.6

2- 55/64 2.859375 .02859375 1.4 .0571875 2.8 .114375 5.7

2- 7/8 2.875 .02875 1.4 .0575 2.8 .115 5.7

2- 57/64 2.890625 .02890625 1.4 .0578125 2.8 .115625 5.7

2- 29/32 2.90625 .0290625 1.4 .058125 2.9 .11625 5.8

2- 59/64 2.921875 .02921875 1.4 .0584375 2.9 .116875 5.8

2- 15/16 2.9375 .029375 1.4 .05875 2.9 .1175 5.80

2- 61/64 2.953125 .02953125 1.4 .0590625 2.9 .118125 5.9

2- 31/32 2.96875 .0296875 1.4 .059375 2.9 .11875 5.9

2- 63/64 2.984375 .02984375 1.4 .0596875 2.9 .119375 5.9

3 3 .03 1.5 .06 3.0 .12 6.0

Basic Components of an X-ray Tube

Types of Scatter Radiation

Cathode Structure

Low-voltagepowersupply

Focusing cup Focalspot

X-ray beam

Filament

High-voltage Power supply

Electron beam

Target

Anode structure ⊕

Tube envelope

Test piece

(a) Internal scatter

(b) Side scatter

(c) Back scatter

Radiographic Film Interpretation

Arc strikes

DEFINITION: Any localized heat-affected zone or change in the contour of the surface of the finished weld or adjacent

base metal resulting from an arc or heat generated by the passage of electrical energy between the surface of the finished weld, base material and a current source, such as welding electrodes or magnetic particle inspection electrodes.

RADIOGRAPHIC APPEARANCE:A localized area, rounded or irregular, and generally found adjacent to the edge of the weld image on the

base metal. The density of the indication appears lighter when the discontinuity is convex from the addition of filler metal with arc strikes resulting from SMAW process. The density of the indication appears darker when the discontinuity is concave resulting from a gouging of the material with arc strikes resulting from the GTAW or SMAW processes.

CAUSES:• Not initiating the arc as required by the welding procedure.• Accidentally striking an arc on the completed weld or base material.• Engaging the magnetizing current prior to establishing firm contact with the test surface when using prods.

• Moving or removing the prods from the test surface without disengaging the magnetizing current.

REMARKS/SPECIAL CONSIDERATIONS:• Arc strikes from welding and MT are generally revealed and dispositioned upon acceptance Visual inspection. However, welding arc strikes may occur from another welding operation in the area after the VT/PT inspections and prior to the RT. Arc strikes occurring in this sequence have a random location and can be found on the weld as well as on the base metal.• Arc strikes from MT will be difficult to detect by RT.Visual inspection should always be performed to confirm arc strikes.

Burn through

DEFINITION:A void or open hole extending into a backing ring or strip, fused

root or adjacent base metal.

RADIOGRAPHIC APPEARANCE:An irregular localized area of darker density, often rounded,

generally found at the center of the weld image. If excessive globules of the weld puddle resulting from the burn through, are present on the inside of the weld joint, their appearance will have a lighter density due to the additional weld metal. The nature of burn through is such that the outline or edges of the indication may or may not be sharply defined.

CAUSES:• Using a weld current higher than allowed by the welding procedure.• Improperly preparing the tungsten electrode tip.• Using too slow a welding speed of travel will cause overheating of the weld puddle.• Improper fit up of the weld joint (unacceptable root gap).

REMARKS/SPECIAL CONSIDERATIONS:• The distinguishing feature between a burn through and a melt through is that a burn through results in an open hole on the ID of the pipe.• Burn through most often occur during the welding of the root pass, although it is possible for this discontinuity to be introduced during the welding of the second layer.• Burn through frequently occur during weld repairs, especially when the repair cavity is at the root depth.• Visual inspection should always be performed, if possible, to confirm bum through.

Concavity

DEFINITION:

RADIOGRAPHIC APPEARANCE:

CAUSES:

REMARKS/SPECIAL CONSIDERATIONS:

Crack, crater

DEFINITION:A linear rupture of metal under stress.

RADIOGRAPHIC APPEARANCE:Generally a star shaped indication with irregular, feathery, twisting lines of darker density oriented within a

weld crater. The discontinuity is usually shallow, therefore, the indication may not be as pronounced as indications produced from other types of cracking.

CAUSES:• Improper termination of the welding arc by abruptly removing the arc.• Not adhering to the parameters of the welding procedure.• Incomplete filling of the weld crater.

REMARKS/SPECIAL CONSIDERATIONS:• It is to be emphasized that although the discontinuity and resulting radiographic indication is generally star shaped, crater cracking does not always take this shape.• Random radiographic indications from crater cracking may be oriented in any direction to the weld axis.

Crack, longitudinal(shown in the root)


RADIOGRAPHIC APPEARANCE:Irregularly shaped, feathery, twisting lines of darker density

oriented along the axis of the weld.

CAUSES:• Improper fit-up of joint.• Contamination of base material.• Violation of the welding procedures.

REMARKS/SPECIAL CONSIDERATIONS:• Longitudinal cracks can occur throughout the weld; in the centerline, fusion lines and in the root.

• Cracking can, at times, be difficult to detect due to the geometricprinciples of the radiographic technique.

Crack, transverse


RADIOGRAPHIC APPEARANCE: Irregularly shaped, feathery, twisting lines of darker density

oriented perpendicular to the axis of the weld. Transverse cracks are generally tight discontinuities, therefore producing subtle indications on the radiograph.

CAUSES:• Transverse cracks are generally the result of longitudinal shrinkage strains acting on weld metal of low ductility. Most commonly found in weld joints having a high degree of restraint.

REMARKS/SPECIAL CONSIDERATIONS:• Cracks may be limited in size and completely within the weld metal, but may also propagate from the weld metal into the adjacent heat affected zone.• Orientation and subtleness of the discontinuity can, at times, be difficult to detect due to the geometric principles of the radiographic technique.• Cracking indications can be masked in the as-welded condition.

Crater pits

DEFINITION:An approximately circular surface condition extending into the weld in an irregular manner.

RADIOGRAPHIC APPEARANCE:The indication will appear as a circular dot with darker density, similar to porosity, in the root area of

consumable insert welds. However, due to the irregular nature of discontinuity, the edge of the indication is usually not as defined as porosity. The irregularity of the discontintinuity can produce a "halo" effect on the edge of the indication, distinguishing a crater pit from porosity. The radiographic indication from crater pits can range from subtle to pronounced, depending on the severity of the pit.

CAUSES:• Improper termination of the welding arc.

• Not adhering to the parameters of the welding procedure.

REMARKS/SPECIAL CONSIDERATIONS:• The indications from crater pits can be misinterpreted as porosity.• Porosity can occur anywhere in the weld, while crater pits occur in the weld root area.• Visual inspection should always performed, if possible to confirm crater pits.• Additional radiography, e.g. putting the indication in the sidewall or profile view, may be employed to assist in confirmation of the discontinuity.

Incomplete fusion of a consumable insert

DEFINITION:Incomplete melting of the consumable insert without fusion and bonding to the base metal along one or

both sides of the consumable insert.

RADIOGRAPHIC APPEARANCE:A uniform elongated band or localized bad of lighter density in the center of the weld image, oriented along

the axis of the weld. The width of the band appears approximately equal to the diameter of the consumable insert.

The indication may appear in the following ways• The indication may appear with both edges straight with abrupt density transitions from the insert area to the base material area. This indicates lack of filling or blending to the base metal, with both sides of the insert not fused.• The indication may appear with one edge having a smooth, gradual density transition from the insert area to the base material area and the other edge straight with an abrupt density transition from the insert area to the base material area. This indicates the former edge is blended with fusion into the adjacent base metal and the latter edge is not fused.

CAUSES:• Improper fit up of the weld joint.• Using too low a welding current.• Using too fast of a travel speed.• An incorrect torch angle.

• An improper motion or weaving technique of the torch.

REMARKS/SPECIAL CONSIDERATIONS:• Visual inspection should always be performed, where possible, to confirm incomplete fusion of the insert, when viewed on radiographs.

Lack of fusion

DEFINITION:Lack of complete fusion of some portion of the metal in a weld

joint with the adjacent metal. The adjacent metal may be either base metal or previously deposited weld metal. When the discontinuity occurs between a weld bead and the adjacent base metal, the term "lack of sidewall fusion" is often used, does not occur in the root.

RADIOGRAPHIC APPEARANCE:Irregularly edged, or straight and irregularly edged lines of

darker density oriented along the axis of the weld. If lack 6f fusion occurs between weld beads, both edges of the indication may be irregular as they indicate the weld puddle not fusing to the contour of the previously deposited weld beads. If the lack of fusion occurs between a weld bead and base metal, one edge of the indication will be straight, as it indicates the weld puddle not fusing to the prepared base meal. Sometimes the lines are interspersed with darker density spots, of varying shapes, indicating voids resulting from the lack of fusion.

CAUSES:• Insufficient welding current to melt the adjacent metal.• Too fast a welding speed of travel will not allow for fusion to the adjacent metal.• Too fast a welding current to melt the adjacent metal.• Improper torch or electrode angle may prohibit melting of the adjacent metal.• Improper placement of weld passes may cause a sharp valley to form.• Lack of proper access to the face of weld joint.• Tightly adhering oxides resulting from improper cleaning of items to be welded.

REMARKS/SPECIAL CONSIDERATIONS:• Lack of fusion on the under bead side of the weld, lying in a horizontal plane, tends to be undetectable but often the sides of lack of fusion lines tend to curl out of the horizontal plane and are recorded on the radiograph.• A distinguishing characteristic between lack of fusion and incomplete penetration is that lack of fusion can occur anywhere in the weld and incomplete penetration occurs at the weld root.

Lack of penetration(left – normal fit-up, right – mismatch)

DEFINITION:Lack of penetration of the weld through the thickness of the joint or penetration which is less than

specified.

RADIOGRAPHIC APPEARANCE:Straight, fine edged lines of darker density oriented along the axis of the weld in the area of the root. The

straightness of both edges of the indication's image and location in the center of the weld image help to distinguish incomplete penetration from lack of fusion.

CAUSES:• Insufficient welding current or to fast travel speed.• Improper torch or electrode angle to melt the root land.• In both backing ring joints and joints to be welded from both sides, improper placement of initial weld pass may cause a sharp valley to form at the root weld.• Joints welded from both sides, insufficient removal of the backside prior to welding.

REMARKS/SPECIAL CONSIDERATIONS:• Occurs at the weld root and is always straight, as it is a RT indication of the actual weld joint preparation. The indication can be prominent or subtle depending on the severity of the discontinuity.

Melt through

DEFINITION:A convex or concave irregularity on the surface of a backing ring

or strip, fused root or adjacent base metal resulting from fusing completely through a localized region but without development of a void or open hole.

RADIOGRAPHIC APPEARANCE:A localized area, usually rounded, and generally found at the

center of the weld image. The density of the indication appears lighter when the discontinuity is convex and darker when the discontinuity is concave.

CAUSES:• Using a weld current higher than allowed by the welding procedure.• Improperly preparing the tungsten electrode tip.

• Using too slow a welding speed of travel will cause overheating.• Improper fit up of the weld joint (unacceptable root gap).

REMARKS/SPECIAL CONSIDERATIONS:• The entire thickness of metal is melted or re-melted and deforms, no hole or void develops as with a burn through.• Melt through most often occurs during the welding of the root pass, although it is possible for this discontinuity to be introduced during the welding of the second layer. Visual inspection should always be performed, if possible, to confirm melt through.

Offset(misalignment/mismatch, shown with LOP)

DEFINITION:Lateral misalignment of two butt joint members of equal

thickness.

RADIOGRAPHIC APPEARANCE:Offset on piping weld joints can appear on the film in different

ways. The radiographic image is dependent upon the orientation of the offset to the beam of radiation. When the offset condition is parallel to the beam of radiation, the offset image may appear as an abrupt density change, generally half way across the width of the weld image. When the offset condition is perpendicular to the beam of radiation, and the entire image of the item is on the film, the offset image will appear in the sidewall or profile view, as lateral misalignment of the members with a high-low effect of the pipes' ID and OD.

CAUSES:• Improper fit-up or fixturing may cause the members to be offset. Improper welding block sequencing on the root pass.

REMARKS/SPECIAL CONSIDERATIONS:• Visual inspection should always be performed to confirm questionable offset conditions when viewed on radiographs.

Oxidation

DEFINITION:A condition resulting from partial or complete lack of purge of a surface which is heated during welding

resulting in formation of oxide on the surface. This condition may range from slight oxidation through the formation of heavy black scale to the extreme of a very rough surface having a rough crystalline appearance.

RADIOGRAPHIC APPEARANCE:Highly irregular, low density area, with a wrinkled or sugared appearance in the center of the weld image.

The condition may extend for the entire circumference of the weld when there is a complete loss of purge. The condition may only be localized, in one or more areas of the weld, occurring whenever the purge is partially interrupted.

CAUSES:• Loss of internal purge gas resulting in an unshielded molten weld puddle on the ID.• High oxygen content in purge gas or path.• Moisture in the area of the weld, due to inadequate drying of the purge path, leakage, etc...

REMARKS/SPECIAL CONSIDERATIONS:• A visual inspection should always be performed, if possible, to confirm oxidation.• Oxidation generally occurs during the flowing of the weld root. However, this condition may occur during welding if there is a degree of root reflow, loss of purge, or moisture present. Oxidation frequently occurs during weld repairs.

Overlap (re-entrant angle)

DEFINITION:The protrusion of weld metal beyond the weld toes or weld root.

RADIOGRAPHIC APPEARANCE:Overlap conditions on the OD of piping butt weld joints should be an extremely rare occurrence in as much

as a satisfactory VT and other surface inspections, such as PT or MT are required prior to RT. However, overlap on the internal weld surface consumable insert piping weld butt joints can appear on the film in different ways. The radiographic image is dependent upon the orientation of the overlap to the beam of radiation. When the overlap condition is not located in the sidewall or profile view, the overlap image will appear consistent with that of convexity with an abrupt density change at the fusion line of the weld root image. When the offset image is in the sidewall or profile view, it will appear as roll over of the weld root reinforcement with an unsatisfactory blending at the fusion line of the weld root image.

CAUSES:• Too slow of a welding speed.• Too low or too high of a welding current.• Incorrect torch or electrode angle.

REMARKS/SPECIAL CONSIDERATIONS:• Visual inspection should always be performed, where possible, to confirm questionable root surface conditions when viewed on radiographs.

Porosity(right – clustered porosity, bottom left – distributed porosity, bottom right - aligned porosity in the root)

DEFINITION:Gas pockets or voids in weld metal.

RADIOGRAPHIC APPEARANCE:Usually spherically shaped areas of darker density and may be

scattered throughout single pass welds or throughout several passes of multiple pass welds. Although usually spherical in shape, porosity may also occur as nonspherical pockets and appear on the radiograph as elongated voids, sometimes referred to as "piping or wormhole porosity". The density of the indication varies directly with the diameter or magnitude of the pore.

CAUSES:• Faulty welding techniques such as using too long an arc with the SMAW process.• Improper cleaning of the weld joint.

REMARKS/SPECIAL CONSIDERATIONS:None.

Root razorback condition

DEFINITION:An oxide membrane, gray in color, with a sharp ridge or peak and ribs from the peak to the edge giving it a

herringbone effect. Also known as "reverse center line crease."

RADIOGRAPHIC APPEARANCE:The image of root razorback is consistent with that of convexity with an associated herringbone appearance

and sharp peak at the center. The lightest density of the image is in the center and is dependent upon the height of peaked condition. The density of the image gradually increases as the condition blends into the base metal.

CAUSES:• Moisture in the area of the weld. Moisture in the purge gas.

REMARKS/SPECIAL CONSIDERATIONS:• This is one of the most common root surface defects encountered when welding Ni-Cu and Ni-C-r-Fe.• Visual inspection should always be performed, where possible, to confirm root razorback condition when viewed on radiographs.

Root surface centerline crease

DEFINITION:An intermittent or continuous peripheral centerline concavity formed on the root surface.

RADIOGRAPHIC APPEARANCE:The image of centerline crease is consistent with that of concavity with an associated herringbone

appearance. If the crease has a notch or a questionable blending condition at the center, the image will crease oriented along the axis of the weld.

CAUSES:• Thick cover pass over a consumable insert that had minor concavity. Excessive welding current.

REMARKS/SPECIAL CONSIDERATIONS:• Visual inspection should always be preformed, where possible to confirm questionable centerline crease when viewed on radiograph.• Approved workmanship sample radiographs may be employed to evaluate centerline crease when a visual inspection is not possible.

Root surface concavity

DEFINITION:A depression on the root surface of the weld, which may be due to

gravity, internal purge or shrinkage.

RADIOGRAPHIC APPEARANCE:The image of concavity may appear as intermittent elliptical areas

or elongated bands of darker film density oriented along the axis of the weld in the center of the weld image. The width of the image is consistent with the weld root width. The darkest density of the concavity's image is generally in the center and is dependent up6n the depth of the concavity. The density of the image gradually decreases as the concavity blends into the base metal.

CAUSES:• Improper fit up of the weld joint.• Using too high of a welding current, too slow of a travel speed, or extremely high purge gas flow rate.

REMARKS/SPECIAL CONSIDERATIONS:• Visual inspection should always be preformed, where possible to confirm questionable concavity when viewed on radiograph.

Root surface convexity

DEFINITION:Reinforcement of the root surface of a butt-fused type weld.

RADIOGRAPHIC APPEARANCE:The image of convexity may appear as intermittent elliptical areas or elongated bands of lighter film

density oriented along the axis of the weld in the center of the weld image. The width of the image is consistent with the weld root width. The lightest density of the convexity's image is generally in the center and is dependent upon the height of the convexity blends into the base metal.

CAUSES:• Using to low or high of a welding current. Using too slow travel speed when welding.

REMARKS/SPECIAL CONSIDERATIONS:• Visual inspection should always be performed, when possible, to confirm questionable convexity when viewed on radiographs.

Slag

DEFINITION: Non-metallic solid material entrapped in weld metal or

between weld metal and base metal.

RADIOGRAPHIC APPEARANCE: Well defined, irregularly shaped, uniformly darker density

areas usually elongated along the axis of the weld.

CAUSES:• Improper fit-up, such as inadequate bevel of the joint sides.• Using too low a welding current for the size of electrode.• Faulty welding techniques such as wrong electrode position or orientation.• Improper bead placement causing sharp valleys or undercutting between the beads.• Improper interpass cleaning of slag from the surface.

REMARKS/SPECIAL CONSIDERATIONS:• Slag is a by-product of the burning of the flux covering on welding roods. Thus, slag inclusions are associated with the SMAW process.• Slag inclusions can occur throughout the weld, in the center of the weld, in fusion lines and in the root.

Tungsten inclusion

DEFINITION:Metallic tungsten inclusions in the weld deposit.

RADIOGRAPHIC APPEARANCE:Irregularly shaped spots of low film density areas, usually

random in size and location. They are solid or liquid bits of tungsten electrode from the TIG welding process that drop or are melted from the electrode and become entrapped in the weld puddle. Tungsten inclusions appear as low or light density areas on the radiograph because of the differences of radiographic absorption between the inclusion and surrounding metal. Tungsten is denser radiographically then the surrounding metal and therefore absorbs more radiation. This, in turn, allows fewer rays to reach the film.

CAUSES:• Overheating the tungsten electrode due to excessive current for the particular electrode size.• Defective tungsten electrode (flaking of particles).• Dipping the tungsten into the molten puddle.

REMARKS/SPECIAL CONSIDERATIONS:None.

Undercut

DEFINITION:An intermittent or continuous groove on the external surface of

the base metal along the edge of the weld.

RADIOGRAPHIC APPEARANCE:An irregular, elongated area of darker density oriented along the

external fusion line of the weld image to the base metal.

CAUSES:• Excessive welding current.• Using too long an arc length will result in a gouging effect.• Using excessive welding speed of travel.• When using the GTAW process, adding an insufficient amount of filler metal.• An incorrect electrode angle can cause a gouging effect.

REMARKS/SPECIAL CONSIDERATIONS:• External undercut is readily revealed and dispositioned upon acceptance Visual inspection.• Visual inspection should always be performed to confirm questionable external undercut when viewed on radiographs.

Undercut, root

DEFINITION:An intermittent or continuous groove in the internal

surface of the base metal, backing ring/strip along the edge of the root of the weld.

RADIOGRAPHIC APPEARANCE:An irregular, elongated area of darker density oriented

along the internal fusion line of the weld image to the base metal.

CAUSES:• Improper fit up of the weld joint.• Excessive current during welding• When using the GTAW process, adding an insufficient amount of filler metal. An incorrect electrode angle can cause a gouging effect.

REMARKS/SPECIAL CONSIDERATIONS:• Radiographic evaluation of root undercut in backing ring joints can be based on workmanship sample radiographs as well as the use of slotted shims.

Weld splatter

DEFINITION:In arc welding, the metal particles expelled during welding which do not form a part of the weld.

RADIOGRAPHIC APPEARANCE:Small, rounded areas of lighter density generally found adjacent to the edge of the weld image on the base

metal.

CAUSES:• There will be some weld spatter when using the SMAW process. However, long arcing is a factor.• Lack of concentricity or damage to the electrode flux.

REMARKS/SPECIAL CONSIDERATIONS:• Weld splatter is most commonly found when the SMAW welding process is employed.• Weld spatter is generally revealed and dispositioned upon acceptance Visual inspection. However, weld spatter may occur from another welding operation in the area after the acceptance VT/PT inspections and prior to the RT.

Probable Causes and Corrective Action for Automatic Film Processing

Q uality o r Artifiac tPro b ab le C ause C o rrec tive Ac tio n Q ua lity o r A rtif iactP ro b ab le C a us e C o rrective Actio n

D en sity to h igh O verd eve lo pm en t G u ide m a rks Im prope rly ad jus ted gu ide s in p rocesso r

C heck c lea rance be tw een gu id e dev ice s and ad jacen t ro lle rs o r o the r com po nents

R o lle r a b rasions S top o r hes ita ting ro lle rsBe sure a ll ro lle rs a re in the ir p rope r pos itions , and tha t end p lay is su ffic ien t fo r ro lle rs to tu rn free ly

D en sity to low U n derdeve lopm e n t R an dom scra tches or sp o ts

D irt on fe ed tray C lean processo r fe ed tray freq uen tly w ith so ft c lo th

Irregu la r dep os it C aused by d ir t o r p rec ip ita te in water sup p lied to w ash ing section

If con d itio n is tem po rary, c lean wash rack and rep lace w ash wa te r in p rocesso r; d ra in w ash tank w hen shu tting p rocesso r do wn. If cond itions pe ris t, use fil te rs in incom in g wa te r lin es

C o n tam ination D ark l ines o r spots P ressu re m arks ca used by bu ild -u p o f fo re ign m a tte r on ro lle rs o r by im prope r ro lle r c le arances , usu a lly in de ve lope r section

C lean ro lle rs th rou gh ly and m ain ta in p rop er c le ara nces

"B lack com ets" w ith ta ils extend ing in d irection o f f ilm trave l cau sed by rus t o r o the r iron pa rtic les d ropp ing on film , usua lly a t en trance a ssem b ly

C lean a ll en trance assem b ly co m pon en ts . A pp ly a l igh t coa t o f g re ase to m icroswitch sp ring s and te rm in a ls . If a ir co nta ins iro n-b ea rin g dust, fil te r a ir su pp ly to p rocessing room

C on trast to low U n derdeve lopm e n t S ee und e rd eve lo pm en t a bove "P i lin es" So ca lled be cause they o ccu r 3 .14 tim es the d iam e te r o f a ro lle r a way fro m the lead ing ed ge o f a film

M ost com m on ly in ne w ly-ins ta lled o r fresh ly c leane d proce sso rs. T e nds to d isappe ar w ith use

C o n tam ination S ee con ta m ination above S trea ks A ssoc ia ted w ith tem po o f w o rk

F o g O verd eve lo pm en t D eve lope r tem pe ra ture to h igh . F o llow te m pera ture recom m enda tion s fo r deve lope r and p rocesso r used .

P oo r d ry ing Processing U nde rep le n ishm ent o f so lu tions . C heck fo r p inched tub ing in re p len ish m en t sys tem .Inad equa te w ash ing . C heck flow o f wash w a te r

A ssoc ia ted w ith de ve lopm e n t

C logged deve lope r rec ircu la tion sys te m . C han ge fil te r ca rtridge regu la rly . C h eck rec ircu la tion pum p

D rying D ryer tem pe ra tu re to low .F o llow tem pera tu re recom m enda tion s fo r deve lope r and p rocesso r used

A ssoc ia ted w ith d rye r D irty tubes in d rye r. C lean drye r tub es

D eve lope r tem pe ra ture to h igh . F o llow te m pera ture recom m enda tion s fo r deve lope r and p rocesso r used . Im prope rly m ixed chem ica ls . F o llow instru ction s fo r p repe ra tion o f chem ica ls

Im prope r rep len ishm e n t o f deve lope r. C he ck fo r c logg ed s tra ine rs o r p inched tubb ing in deve lope r rep len ishm en t sys tem . D eve lo per tem p era tu re to lo w.F o llow tem p era tu re recom m enda tion s fo r deve lope r and p rocesso r used .

F ixer in de ve lop m ent tanks. U se extrem e ca re w hen ins ta lling or rem ov ing fixe r rack in p rocesso r. A lways u se sp lash gua rd wh en fixe r rack is be in g rem o ved or rep la ced. D o no t exchan ge racks be tw een fixe r and deve lope r com p artm en ts

Lo ng in te rva l b e tw een feed ing o f fi lm s. "de lay stre aks" ca used by in te rva l o f 15 m inu te s or m ore in fee d ing o f succes ive film s, w h ich resu lts in d ry ing o f so lu tio ns on p ro cessor ro lle rs exp osed to a ir. W ipe dow n exp osed w ith dam p c lo th a nd proce ss a c lea ring she e t be fo re ra d iograph s

Probable Causes and Corrective Action for Processed Radiographic FilmQuality or ArtifiactProba ble Ca use Corre ctive Action Quality or ArtifiactProbable Ca use Corrective Action

Density to high Overexposure Contrast to high High subject contrast Increase tube voltage

High film contrast Use a film with lower contrast characteristics

Contrast to low Low subject contrast Reduce tube voltage

Overdevelopment Reduce development time or developer temperature

Low film contrast Use a film with higher contrast charteris tics

Density to low Underexposure Check exposure (time and radiation intensity); if a sspecified, increase exposure by 40% or more

Underdevelopment Increase development time or developer temperature. Replace weak (depleted developer)

Underdevelopment Finely mottled fog Stale film Use fresh filmFog on edge or corner

Defective cassette Discard cassette

Material between screen and film

Remove material Yellow stain Depleted developer Replace developer solution

Poor definition Testpiece-to-film distance too long

If possible, decrease testpiece-to-film distance; if not, increase source-to-film distance

Failure to use stop bath or rinse

Use stop bath, or rinse throughly between developing and fix ing

Source-to-film distance to short

Increase sourc-to-film distance

Depleted fixer Replace fixer solution

Focal spot to large Use small focal spot or increase source-to-film distance

Dark c ircular marks Film splashed with developer prior to immersion

Immerse film in developer with care

Screens and film not in close contact

Ensure intimate contact between screens and film

Dark spots or marblelike areas

Insuffic ient fix ing Use fresh fixer solution and proper fix ing time

Film graininess too coarseUse finer-grain film Dark branched lines and spots

Static discharge Unwrap film carefully. Do not rub film togther. Avoid c lothing productive of static electric ity

Fog Light leaks in darkroom W ith darkroom unlighted, turn on all lights in adjoining rooms; seal any light leaks

Dark fingerprints Touching undeveloped film with chemically contaminated fingers

W ash hands throughly and dry, or use clean, dry rubber glovesExposure to safelight Reduce safelight wattage and

check filtersLight fingerprints Touching undeveloped film

with oily or greasy fingersW ash hands throughly and dry, or use clean, dry rubber gloves

Dark spots or s treaks

Developer contaminated with metallic salts

Replace developer solution

Cresent shaped light areas

Faulty film handling Keep film flat during handling. Use only c lean, dry film hangers

Light c ircular patches

Air bubbles on film during development

Agitate immediately upon immersion of film in developer

Film exposed to heat, humidity , or gases

Store film in cool, dry place not subject to gases or vapors

Circular or dropshaped light patches

W ater or fixer splashed on film before development

Avoid splashing film with water or fixer solution

Overdevelopment Reduce development time or developer temperature

Light spots or sreasDust or lint between screens and film

Keep screens c lean

Developer contaminated Replace developer Sharply outlined light or dark areas

Nonuniform development Agitate film during development

Exposure during processing

Do not inspect film during processing until fix ing is completed

Reticulation (leather grain appearance)

Temperature gradients in processing solutions

Maintain all solutions at uniform, constant temperature

Frilling (loosening of emuls ions from film base)

Fixer solution to warm Maintain correct temperature of the fix ing solution

Frilling (loosening of emulsions from film base)

Fixer solution depleted Replace fixer solution

Stored film inadequately protected from radiation

Attach strip of lead to loaded film holder and place in film-storage area. Develop test film after two to three weeks; if image of s trip is evident, improve radiation shielding in storage area

Increase development time or developer temperature. Replace weak developer

View with higher-intensity light, check exposure (time and radiation intensity); if as specified, reduce exposure by 30% or more

NDT Handbook

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