Day-1 LECTURE 2-Welding Technology

7/31/2019 Day-1 LECTURE 2-Welding Technology

1/64

SAE & AISI DEVELOPED MOST COMMONNUMBERING & CLASSIFICATIONOF STEEL

4 DIGIT NUMBERING SYSTEM

1ST DIGIT TYPE OF STEEL

2ND DIGIT % OF ALLOYING ELEMENT

LAST TWO CARBON CONTENT IN HUNDREDDIGITS OF A PERCENT

CARBON STEEL & ALLOY STEELCLASSIFICATION SYSTEM


2/64

4 DIGIT NUMBERING SYSTEM

EXAMPLE

AISI 2315 NICKEL STEEL

ABOUT 3% NICKEL (Ni)

0.15 % CARBON (C)



3/64

MATERIAL CODE TYPE OF STEEL1XXX CARBON STEELS

12XX SPECIAL SULPHUR CARBON STEEL

12XX PHOSPHOROUS CARBON STEEL

13XX MANGNESE STEEL

2XXX NICKEL STEELS

3XXX NICKEL CHROMIUM STEELS

4XXX MOLYBDENUM STEELS5XXX CHROMIUM STEELS

6XXX CHROMIUM VANADIUM STEELS

7XXX TUGSTEN STEELS

9XXX SILICON MANGANESE STEELS



4/64

PERCENTAGE OF CARBON

ALLOY % OF CARBON

WROUGHT IRON NO CARBON ( < 0.08%)

LOW CARBON STEELS 0.15 % CARBON (MAX)

0.25 - 1.5 % MANGANESE

MILD STEEL 0.15 - 0.29 % CARBON

MEDIUM CARBON STEEL 0.25 - 0.50 % CARBON

0.60 - 1.65 % MANGANESE

HIGH CARBON STEELS 0.50 - 1.03 % CARBON

0.30 - 1.00% MANGANESELOW ALLOY STEELS 0.29 % CARBON (MAX.)

TOTAL METAL ALLOYS


5/64

CARBON EQUIVALENT

C.E. = % Mn

6

% Cr + % Mo

10

% Ni

20

% C % Cu

40+

+ + +

if C.E. < 0.40% MATERIAL IS READILY WELDABLE

C.E. > 0.40% SPECIAL CONTROLS REQUIRED

PREHEATING

LOW HYDROGEN PROCESSES

PROCEDURE SHOULD BE QUALIFIED


6/64

ELECTRODES FOR CARBON & LOW - ALLOY STEEL (SMAW)

E60 1 0ELECTRODE

STRENGTH IN KSI POSITION

TYPE OF COATING& CURRENT

AWS ELECTRODE CLASSIFICATION SYSTEM

AWS SPECIFICATION A 5.1


7/64

E80 1 8 - B1ELECTRODE

80 KSI Min.

ALL POSITION

AC OR DCEP

CHEMICAL COMPOSITION

OF WELD METAL DEPOSIT



8/64


SIGNIFICANCE OF 3RD DIGIT - POSITION

3RD DIGIT POSITION

1 FLAT, HORIZONTAL, VERTICAL, OVERHEAD

2 FLAT AND HORIZONTAL ONLY

3 FLAT, HORIZONTAL, VERTICAL DOWN,

OVERHEAD

EXX X X

POSITION


9/64


SIGNIFICANCE OF 4TH DIGIT

4TH DIGIT TYPE OF COATING CURRENT

0 CELLULOSE SODIUM DCEP

1 CELLULOSE POTASSIUM AC or DCEP or DCEN

2 TITANIA SODIUM AC OR DCEN

3 TITANIA POTASSIUM AC OR DCEP

4 IRON POWDER TITANIA AC or DCEP or DCEN

5 LOW HYDROGEN SODIUM DCEP

6 LOW HYDROGEN POTASSIUM AC or DCEP

7 IRON POWDER IRON OXIDE AC or DCEP or DCEN

8 IRON POWDER LOW HYDROGEN AC or DCEP

EXX X X TYPE OF COATING &CURRENT


10/64


CHEMICAL COMPOSITION OF WELD DEPOSIT

SUFFIX % Mn %Ni %Cr %Mo %V

A1

B1

B2 1

B3 2 1

C1 2

C2 3

C3 1 0.15 0.35

D1 & D2 1.25 2.00 0.25 0.45

G 0.50 0.30 Min. 0.20 Min. 0.10 Min.

EXXXX - XXSUFFIX


11/64


AWS SPECIFICATIONS FOR GMAW ELECTRODES

BASE MATERIAL AWS SPECIFICATION

CARBON STEEL A 5.18

LOW ALLOY STEEL A 5.28ALUMINIUM ALLOY A 5.10

COPPER ALLOY A 5.7

MAGNESIUM A 5.19

NICKEL ALLOYS A 5.14

STAINLESS STEEL A 5.9

TITANIUM A 5.16


12/64

CARBON STEEL ELECTRODES (GMAW)

ER70 S- X

ELECTRODE OR ROD

STRENGTH IN KSI

SOLID ELECTRODE WIRE

CHEMICAL COMPOSITION& SHIELDING



13/64

CARBON STEEL ELECTRODES FOR GMAW

AWSCLASSIFICATION

% C %Mn %Si % OTHER

Ti Zi Al

E 70S 20.6 0.40 0.70 0.05 0.02 0.05

E 70S 3 0.06 0.15 0.90 1.40 0.45 0.70

E 70S 4 0.07 0.15 0.65 0.85

E 70S 5 0.07 0.19 0.30 0.60 0.500.90

E 70S 6 0.07 0.15 1.40 1.85 0.80 1.15

E 70S 7 0.07 0.15 1.50 2.00 0.50 0.80

CHEMICAL COMPOSITION


14/64

CARBON STEEL ELECTRODES FOR GMAW

AWSCLASS.

WELDING ELECTRODE STRENGTH REQUIREMENTS

(AS WELDED)

POLARITY EXTERNALGAS SHIELD

TENSILESTRENGTH

MIN.

YIELDSTRENGTH

MIN.

%ELONGATION

MIN.

KSI KSI

E 70S 2 DCEP CO2 72 60 22

E 70S 3 DCEP CO2 72 60 22

E 70S 4 DCEP CO2 72 60 22

E 70S 5 DCEP CO2 72 60 22

E 70S 6 DCEP CO2 72 60 22

E 70S 7 DCEP CO2 72 60 22

MECHANICAL PROPERTIES

SHIELDING GAS MAY BE ARGON CO2 OR ARGON O2 MIXTURE


15/64


GTAW ELECTRODES

AWSCLASS.

CHEMICAL COMPOSITION COLORCODE

EWP PURE TUNGSTEN GREEN

EWCe 2 97.3% TUNGSTEN, 2% CERIUM OXIDE ORANGE

EWLa - 1 98.3% TUNGSTEN, 1% LANTHANUM OXIDE BLACK

EWTh - 1 98.3% TUNGSTEN, 1% THORIUM OXIDE YELLOW

EWTh - 2 97.3% TUNGSTEN, 2% THORIUM OXIDE RED

EWZr - 1 99.1% TUNGSTEN, 0.25% ZIRCONIUM OXIDE BROWN

EWG 94.5% TUNGSTEN, REMAINED NOTSPECIFIED

GRAY


16/64

SUFFIX LETTER DESIGNATE THE CHEMICAL COMPOSITION OFTHE DEPOSITED WELD METAL

ALLOY STEEL FILLER METAL

AWS FILLER METAL SPECIFICATIONS

SUFFIX LETTER CHEMISTRY

A C Mo STEEL

B Cr Mo STEEL

C or Ni Ni STEEL

D Mn Mo STEEL

NM NI Mo STEEL

G,K,M and W OTHER LOW ALLOY STEEL


17/64

1. ALWAYS USE A LOW - HYDROGEN WELDING PROCEDURE,PROCESS & FILLER METAL

2. SELECT A FILLER METAL THAT MATCHES THE STRENGTHLEVEL OF THE ALLOY STEEL

3. SELECT A FILLER METAL THAT COMES CLOSE TOMATCHING THE COMPOSITION OF ALLOY STEEL

4. USE PROPER WELDING PROCEDURE

ALLOY STEEL WELDING

FOUR FACTORS FOR SUCCESSFUL ALLOY STEEL WELDING


18/64

LOW CARBON STEEL WELDING

AISIGRADE

CARBONEQUIVALENT

(% CE)

WELDINGPROCESS

SPECIALPRECAUTION

(IF ANY)

ELECTRODE

C-1008

C - 1025

< 0.40% SMAW NIL E 60XX

E 70XX

LOW CARBON STEEL

O


19/64

MEDIUM CARBON STEEL WELDING

AISIGRADE

CARBONEQUIVALENT

(% CE)

WELDINGPROCESS

SPECIALPRECAUTION

(IF ANY)

ELECTRODE

C-1030

C - 1050

< 0.40% SMAW NIL E 70XX

MEDIUM CARBON STEEL

HIGH CARBON STEEL WELDING


20/64

HIGH CARBON STEEL WELDING

AISIGRADE

CARBONEQUIVALENT

(% CE)

WELDINGPROCESS

SPECIALPRECAUTION

(IF ANY)

ELECTRODE

C-1055

C - 1095

> 0.40% SMAW PREHEATING

(200 310OC)

PWHT

E 70XX

HIGH CARBON STEEL

LOW ALLOY STEEL WELDING


21/64


WELDINGPROCESS

ELECTRODE SPECIAL PRECAUTION

(IF ANY)

SMAW E 80XX,E 90XX

WITH C1, C2SUFFIX

C < 0.15% NO PREHEAT(EXCEPT FOR HEAVY SECTION)

C > 0.15% PREHEAT UP TO 260OC

STRESS RELIEVING -ADVISABLE

LOW NICKEL STEEL AISI 2315, 2515, 2517

MAJOR ALLOYING ELEMENT % COMPOSITIONCARBON (C) 0.12 0.30%

MANGANESE (Mn) 0.40 - 0.60%

SILICON (Si) 0.20 - 0.45%

NICKEL (Ni) 3.25 5.25%



22/64


WELDINGPROCESS

ELECTRODE SPECIAL PRECAUTION

(IF ANY)

SMAW E 80XX,E 90XX

C < 0.15% NO PREHEAT(EXCEPT FOR HEAVY SECTION)

C > 0.15% PREHEAT UP TO 316OC

STRESS RELIEVING -ADVISABLE

LOW Ni - Cr STEEL AISI 3130, 3135, 3140, 3310, 3316


MANGANESE (Mn) 0.40 0.90%

SILICON (Si) 0.20 0.35%

NICKEL (Ni) 1.10 3.75%CHROMIUM (Cr) 0.55 0.75%



23/64


WELDINGPROCESS

ELECTRODE SPECIAL PRECAUTION (IF ANY)

SMAW E 80XX,

E 90XX

WITH A-1,D-1,D-2 SUFFIX

LOW RANGE OFC & Mn

NO PREHEAT

C >= 0.25% PREHEAT DESIRABLE(121OC TO 149OC)

HIGH RANGE Mn PREHEAT MANDATORY

THICKER SECTION - DO- (240OC TO 290OC)

STRESS RELIEVING ADVISABLE

LOW Mn STEEL AISI 1320, 1330, 1335, 1340, 1345



SILICON (Si) 0.20 0.30%



24/64


WELDINGPROCESS

ELECTRODE SPECIAL PRECAUTION (IF ANY)

SMAW E 80XX,

E 90XXWITH BSUFFIX

LOW RANGE OFC & Cr

NO PREHEAT

HIGH RANGE OFC & Cr

PREHEAT MANDATORY(399OC )

THICKER SECTION - DO- (240OC TO 290OC)

STRESS RELIEVING ADVISABLE

LOW ALLOY Cr STEEL AISI 5015 to 5160MAJOR ALLOYING ELEMENT % COMPOSITION

CARBON (C) 0.12 1.10%


SILICON (Si) 0.20 0.35%

CHROMIUM (Cr) 0.20 1.60%

STAINLESS STEEL


25/64

ALSO CALLED CORROSION - RESISTANT STEELS

THEY DO NOT RUST

STRONGLY RESIST ATTACK BY GREAT MANY LIQUIDS,

GASES & CHEMICALS

GOOD LOW - TEMPERATURE TOUGHNESS & DUCTILITY

GOOD STRENGTH & RESISTANCE TO HIGH TEMP.

IRON AS MAIN ELEMENT, CHROMIUM - 11 TO 30 %

STAINLESS STEEL

STAINLESS STEEL IDENTIFICATION SYSTEM


26/64

IDENTIFICATION BY 3 DIGIT NUMBERS

EXAMPLE - AISI 304

FIRST DIGIT INDICATES GROUP

LAST TWO INDICATES SPECIFIC ALLOY


AISI IDENTIFICATION SYSTEM



27/64


AISI IDENTIFICATION SYSTEM

SERIESDESIGNATION

METALLURGICALGROUP

PRINCIPLEELEMENTS

MAGNETICPROPERTY

2XX AUSTENITIC Cr Ni Mn NON MAGNETIC

3XX AUSTENITIC Cr Ni -DO-

4XX MARTENSITIC Cr MAGNETIC

4XX FERRITIC Cr -DO-

5XX MARTENSITIC Cr Mo -DO-

STAINLESS STEEL WELDING


28/64

THESE DIFFERENCES ARE

LOWER MELTING TEMPERATURE

LOWER THERMAL CONDUCTIVITY

HIGHER COEFFICIENT OF THERMAL EXPANSION

HIGHER ELECTRICAL RESISTANCE


STAINLESS STEEL IS DIFFICULT TO WELD

COMPARE TO CARBON - STEELS

THIS IS BECAUSE OF DIFFERENCE IN

PHYSICAL PROPERTIES.



29/64

SMAW

GTAW

GMAW


MOST POPULAR PROCESSES FOR WELDING STAINLESSSTEEL ARE



30/64

45% HIGHER MANGANESE

NOT HARDENABLE BY HEAT TREATMENT

NON MAGNETIC

MAY BECOME MAGNETIC WHEN COLD WORKED

OR WELDED

ALL AUSTENITIC SS ARE WELDABLE

EXCEPTION TYPE 303 (CONTAINS HIGH SULPHUR)

TYPE 303Se (CONTAINS SELIUM)


AUSTENITIC TYPE STAINLESS STEEL 2XX, 3XX

PROPERTIES


31/64



32/64


AUSTENITIC TYPE STAINLESS STEEL 2XX, 3XX

USE HIGH TRAVEL SPEED

IT REDUCES HEAT INPUT

IT REDUCES CARBIDE PRECIPITATION

IT MINIMIZES DISTORTION

SPECIAL PRECAUTION AGAINST WRAPAGE &DISTORTION(TACK WELDS SHALL BE TWICE AS NORMAL)

THIN MATERIAL - DIFFICULT TO COMPLETELY AVOID BUCKLING

RECOMMENDATIONS:-



33/64

WELDABLE EXCEPT 430F (CONTAINS HIGH SULFUR)

COEFFICIENT OF THERMAL EXPANSION SAME AS CS

TENDENCY OF GRAIN GROWTH AT T >= 871O C

WELDING PROCESSES THAT TEND TO INCREASE

CARBON PICK UP ARE NOT RECOMMENDED e.g.

GMAW WITH CO2 SHIELDING

OXYFUEL PROCESS


FERRITIC TYPE STAINLESS STEEL 4XX



34/64

RECOMMENDATIONS

HEAVIER SECTION - PREHEAT 205O C TO 210O C

ANNEALING - 760O C TO 816O C FOLLOWED BY

WATER OR AIR QUENCH

PEENING THE WELD (TO IMPROVE TOUGHNESS)

USE AUSTENITIC SS FILLER METAL (IF HT IS

NOT POSSIBLE)


FERRITIC TYPE STAINLESS STEEL 4XX



35/64


MARTENSITIC TYPE STAINLESS STEEL 4XX, 5XX

HARDENABLE BY HEAT TREATMENT

MAGNETIC

LOW CARBON TYPE CAN BE WELDED WITHOUT ANY

PRECAUTION

WELDING PROCESSES THAT TEND TO INCREASE CARBON

PICK UP ARE NOT RECOMMENDED

INCREASED CARBON CONTENT INCREASES CRACK

SENSITIVITY IN WELD AREA



36/64

LOW - CARBON TYPE WELDABLE

(WITHOUT PRECAUTIONS)

%C > 0.15 PREHEAT, POST-HEAT REQD.

PREHEAT TEMP. 230O C - 290O C

POSTHEAT TEMP. 650O C - 760O C

(FOLLOWED BY SLOW COOLING)


MARTENSITIC TYPE STAINLESS STEEL 4XX, 5XX



37/64


RECOMMENDED FILLER METAL

SERIES

DESIGNATION

AISI

NO.

POPULAR

NAME


FIRST CHOICE SECOND CHOICE

Cr Ni Mn

Austenitic

201 308 308L

202 308 308L

Cr Ni Austenitic 301 308 308L

302 308 308L

302B 308 309

303 - -

303Se - -

304 18/8 308 308L

304L 18/8 ELC 308L 347

305 308

309 25/12 309



38/64



SERIESDESIGNATION AISINO. POPULARNAME RECOMMENDED FILLER METALFIRST CHOICE SECOND CHOICE

Cr Ni Austenitic 309S 309 -

310 25/20 310 -

310S 310 -

314 310 -

316 18/12 Mo 316 309Cb

316L 18/12 ELC 316L 309Cb

317 19/14 Mo 317 309Cb

321 347 308L

347 19/9 Cb 347 308L

348 19/9CbLTa 347 -


39/64



40/64



SERIESDESIGNATION

AISINO.

POPULARNAME


FIRST CHOICE SECOND CHOICE

Cr Ferritic 405 410 405Cb

430 16 Cr 430 309

430F - -

430FSe - -

446 309 310

501 5 Cr - Mo 502 -

502 5 Cr - Mo 502 -

ALUMINIUM & ALUMINIUM ALLOY


41/64

LIGHT WEIGHT

RELATIVELY HIGH STRENGTH

Al WELDING IS DIFFERENT FROM STEEL WELDING


PROPERTIES



42/64


DESIGNATION OF ALUMINIUM ALLOY GROUPS

MAJOR ALLOYING ELEMENT DESIGNATION

99% MINIMUM Al AND OVER 1XXX

COPPER 2XXX

MANGANESE 3XXX

SILICON 4XXX

MAGNESIUM 5XXX

MAGNESIUM AND SILICON 6XXX

ZINC 7XXX

OTHER ELEMENT 8XXX



43/64


SERIES PROPERTIES USE

1XXX Al 99% OR HIGHER PURITY PRIMARY USED INELECTRICAL &CHEMICALINDUSTRY

2XXX PRINCIPAL ALLOYING ELEMENT Cu

HIGH STRENGTH (WHEN PROPERLYHEAT TREATED)

LESS CORROSION RESISTANCE

OFTEN CLAD WITH Al OR SPECIAL AlALLOY



44/64


SERIES PROPERTIES USE

3XXX

4XXX

5XXX

6XXX

7XXX

8XXX

ALUMINIUM & ALUMINIUM ALLOY WELDING


45/64

Al welding is different from steel welding because of

following properties of steel Al Oxide Surface Coating

Al reacts with O2 in air to produce thin hardfilm of Al - oxide on the surface

Melting point of oxide film 1926o C(3 times melting of Al)

Oxide film absorb moisturefrom air

Moisture - source of H2 causingporosity

Al - Oxide film must be removed prior towelding

Small particles of un-melted Al - Oxide will

causelack of fusion, weld crack




46/64

Al Oxide Surface Coating

Can be removed byMechanical Method - Grinding etcChemical - Cleaning Solution

Welding Fluxes

Electrical - Cathodic Bombardmenthalf cycle of AC GTAW

Oxide film immediately start to form(Weld with 8 hr. of cleaning)

High Thermal Conductivity High Thermal Expansion Coefficient Low Melting Temperature The absence of color change as temperature

approaches the melting point




47/64

GTAW - Used for welding thinnersection (Use AC)

GMAW - Thicker Section

SMAW - Not Popular

OxyAcetylene - Not Popular

Resistance - UsedWelding

Solid State - Used


DISSIMILAR METAL WELDING


48/64

SHOULD BE AS STRONG AS WEAKER OF TWOMETALS JOINED

IMPORTANT TO INVESTIGATE PHASE DIAGRAM

IF MUTUALLY SOLUBLE - JT. CAN BE MADESUCCESSFULLY

IF MUTUALLY NOT SOLUBLE - USE THIRD METALWHICH IS SOLUBLE TO BOTH




49/64

IMPORTANT CONSIDERATIONS

COEFFICIENT OF THERMAL EXPANSION OFBOTH MATERIALS

DIFFERENCE IN MELTING TEMPERATURE

INTERMETALLIC COMPOUNDS FORMEDBETWEEN THE DISSIMILAR METALS

- CRACK SENSITIVITY- DUCTILITY- SUSCEPTIBILITY TO CORROSION




50/64

EFFECTIVE WELDING PROCESSES

ARC WELDING

ULTRASONIC WELDING

COLD WELDING

EXPLOSION WELDING

ELECTRON BEAM WELDING

LASER BEAM WELDING




51/64

POPULAR DISSIMILAR METAL COMBINATIONS

BASE METALS SMAW GTAWGMAW

Al to Mild Steel Use a transition insert of these metals

Al to Low - Alloy Steel - do -Al to S.S. - do -SS(Ferritic) to Low-Alloy ENiCrFe-3 RNiCrFe-3 ENiCrFe-3

Steel

SS(Aus.) to Low-Alloy ENiCrFe-3 RNiCrFe-3 ENiCrFe-3SteelMild Steel to Low Alloy E7018 E70S-X E70S-X

Steel



52/64

HEAT AND WELDING

Heat is employed in most Welding Processes

1. Electric Arc2. Resistance Heating3. High Temperature Flame4. Mechanical Sources - Friction, Ultrasonic5. Exothermic Chemical Reaction

Most Common is Electric Arc

Temperature 5000oC - 20,000oC


53/64

EFFECTS OF WELDING HEAT

1. High Residual Stresses Distortion2. Reduction in ductility & Cracking

change in hardness in HAZ3. Deterioration in toughness

in HAZ4. Loss of Strength in HAZ in

certain work - hardened, quenched & tempered

steel.


54/64

WELDING METALLURGY

Science of Welding closely relates to metallurgy

Metallurgy involves Producing metals from oreMaking & Compounding AlloysReaction of metals to manydifferent activities & situations

Extensive Use of Heat-treatmentMetallurgy in Steel Making & Processing

ForgingFoundry


55/64

WELDING METALLURGY

Welding Metallurgy Special branch of metallurgy

Reaction time - minute/second

Changes of physical propertiesin short period

It deals with Interaction of different metals

Interaction of metals withgases


56/64

WELDING METALLURGY

Metal in Liquid State No Distinct StructureAtoms move freely amongthemselves

As Molten Metal cools Heat Energy decreasesLess mobility of atoms

Near to Solidification Atoms attracted together in adefinite patterns

Three Dimensional lattice

Also called Space Lattices

Crystal


57/64

WELDING METALLURGY

Most Metals in Common Use are in the form of Alloy Substitutional Solid Solution

Interstitial Solid Solution

Inter-metallic Compound

PHASE Each grouping with its owncrystalline structure

Microstructure Overall arrangement of grains, grainboundaries & phases present in alloy


58/64

ALLOTROPES

Allotropic change Substitutional Solid Solution

Interstitial Solid Solution

Inter-metallic Compound

PHASE Each grouping with its owncrystalline structure

Microstructure Overall arrangement of grains, grainboundaries & phases present in alloy

WELDING METALLURGY


59/64

TEMERATURE DISTRIBUTION AROUND A WELD

WELDING METALLURGY


60/64

STEPS IN THE SOLIDIFICATION OF MOLTEN METAL

WELDING METALLURGY


61/64

SOLIDIFICATION PATTERN OF GROOVE WELD

WELDING METALLURGY


62/64

CHARACTERISTICS OF WELDED JOINT IN PURE METAL

CHARACTERISTICS OF WELDED JOINT IN PRECIPITATION HARDENED ALLOY

WELDING METALLURGY


63/64

MICROSTRUCTURE OF DIFFERENT PARTS OF WELD

WELDING METALLURGY


64/64

WELD SHOWING WELD METAL, HEAT AFFECTED ZONE & BASE METAL

Day-1 LECTURE 2-Welding Technology

Documents

Transcript of Day-1 LECTURE 2-Welding Technology