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DOOSAN PROJECTS INDIA PRIVATE LIMITED

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QUALITY PLAN

21. 04. 2008


NON-DESTRUCTIVE EXAMINATION PROCEDURE

4,000MW Coal Based Power Plant Project at

Mundra

(PQMP-NDE-001 Rev.0)


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TABLE

01. Radiographic Testing Procedure.

02. Ultrasonic Testing Procedure.

03. Magnetic Particle Examination Procedure.

04. Liquid Penetrant Examination Procedure.

Attachments: Format of Radiography Offering Report.

Format of Ultrasonic Test Report.

Format of Magnetic Particle Test Report.

Format of Dye Penetration Test Report.

Format of Radiography Interpretation Report.


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01. Radiographic Testing Procedure.

CONTENTS

1. Purpose

2. Scope

3. Reference

4. Construction Equipments and Instruments

5. Procedure

6. Safety


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1. Purpose

Purpose of this procedure is to define the technical requirements and modes of operation to be met as well as the results to be obtained by the erector concerning the Radiogrphy Test by using Ir-192 sources for the welds with thickness from 2 mm to 75 mm..

2. Scope

The scope of this procedure is limited to Radiogrphy Test to be conducted at 4,000MW Ultra Mega Power Project at Mundra Site site.

3. References

ASME Section V : Non-destructive examination.

ASME B31.1 : Power Piping.

ASME Section I : Power Boiler.

4. General

The weld ripples or weld surface irregularities on both the inside (where accessible) and outside shall be removed by suitable process to such a degree that the resulting radiographic image due to any irregularities cannot mask or be confused with the image of any discontinuity.


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5. Personnel

All operator and personnel engaged in radiographic examination shall be in accordance with SNT-TC-1A or equivalent standard.

6. Stage of Examination

The time of inspection shall meet the requirements of codes and/or contracts. The time of inspection are as follows:

(1) After welding and visual inspection if PWHT not applied.

(2) After PWHT (In case of small diameter tubes which is agreed by CGPL, before PWHT)

(3) After repair

(4) Other time upon agreements.

7. Testing Equipment

7.1 Equipment

Gamma radiation with Isotope IR 192 shall be used for thickness up to 75mm.

7.2 Film Type

Radiography film may be of fine grain medium speed high contrast type. The Recommended Brands are AFGA/KODAK/INDU with coding D4/D5/D7 or AX/80/100 and equivalent. For less than 6mm thick job SLOW FILM/D4 or equivalent to be used.


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All films to be used for radiography shall be visibly in good condition and with in the period of usefulness as indicated by the manufacture’s recommendations.

7.3 Screens

Normally 0.13mm thick lead screens will be used for both front and back for IR 192. All Screens shall be handled carefully to avoid dents, scratches dirt etc. on active surface. The screens shall be cleaned with a solvent.

7.4 Radiographic Density

Only single Radiography technique shall be employed to take weld radiography. Under no circumstances two different radiography techniques shall be used to take a radiograph of a particular joint.

The transmitted film density through the radiographic image of the body of appropriate penetrameter and area of interest shall be between 2.0 to 4.

Either a calibrated densitometer or a certified step-wedge density strip shall be used for measuring density of radiographs.

7.5 Geometrical Unsharpness

a) Ug = F × D／d

where Ug : geometric unsharpness

F = Source size, the maximum projected dimension of the radiating source in the plane perpendicular to the distance D from the weld or object being radio graphed.

D = Distance from source of radiation to object being radio graphed.

d = Distance from source side of object being radio graphed to the film.


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t x d

Time =

Maximum geometric unsharpness

Material Thickness (inch) Ug maximum (inch)

Under 2 (50 mm) 0.020 (0.5 mm)

2 through 3 (50 to 75 mm) 0.030 (0.76 mm)

Over 3 through 4 (75 to 100mm) 0.040 (1.0 mm)

Greater than 4 (100 mm) 0.070 (1.75 mm)

b) Source to film distance: SFD = + t Ug

Where D = Source to film distance.

t = Thickness of the specimen.

d = Diameter of the source

c) Exposure time calculation

Film factor x SFD2 x 2N x 60

Rhm x 1002 x source strength in Ci

Where N = Thickness/ Half value Layer of steel

RMH for IR 192 = 0.5

7.6 Technique

a) Single Wall Single Image

In this technique the radiation penetrate one wall thickness only and this technique is recommended for open joints. When complete coverage is


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required for circumferential welds, a minimum of three exposures to be taken 120° apart

Cassette with film & Lead screen

Source

b) Double Wall Single Image

In this technique the radiation penetrate double the wall thickness this

technique is recommended for joints.

Cassette with film & Pb screen

Source

c) Double Wall Double Image

In this technique the radiation penetrate the entire weld at a desired angle so as to get full image on a single film. In elliptical form geometrical reason two exposures is radio graphed on 90° rotations in this technique. Only source side penetrameter shall be used. The radiation beam may be offset from the plane of weld at an angle sufficient to separate the images of the source side and the film side portion of the weld so that there is no overlap of areas.


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Source at angle

Radiation

Weld

Film

d) Panoramic

In this technique the radiation penetrate entire weld on 360°. And the film is wounded the entire circumference of weld and radio graphed in one time. Generally this technique is recommended for the major diameter where placing the source at center is possible.

Weld

Source

Film

7.7 Identification of Radiographs

Location markers which are to appear as radiographic image on film shall be placed on the part not on the exposure holder cassette and their locations shall be marked on the surface of the part being radio graphed in manner permitting the area of interest on the part providing guidance on the radiograph that the technique coverage of the region being examined has been obtained.

Lead location markers will be placed on the specimen at clearly marked interval.


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Location markers shall be placed according to that illustration in ASME SEC V Article 2.

All location markers for DWDI shall be positioned prior to radiography commencing and shall remain in position throughout radiography of that weld of successive exposures.

The segments are to be marked on the welds by using yellow chalk or permanent marker for easy traceability.

7.8 Image Quality Indicators (IQI)

The image quality indicator used will be ASTM plaque or ASTM wire type as specified by ASME SEC V. Din wire type penetrameter may also be used on the basis of the material thickness and type

The ASME wire type penetrameter shall be used as per ASME SEC V

DIN 54109 wire type penetrameter shall be used as per Din standard.

7.9 Sensitivity Requirements

Radiographic sensitivity shall be 2% or better when using Din wire type penetramerts.

7.10 Material for Penetrameter

The material of the penetrameter shall be of similar radiographic density to that of material under examination (i.e.) steel for steel Aluminum for Aluminum etc.


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7.11 Location for Penetrameter

The wire type penetrameter shall be placed on the source side across the weld so that the wires are at 900 to the weld seam.

Where in accessibility prevents placement of the penetrameter on the source side penetrameter may be used on film side and letter “F” shall be placed adjacent to the penetrameter.

7.12 Back Scattering Check

The Lead Letter “B” shall be kept at the back side of the cassette .The size of the Lead Letter Shall be ½” Height x 1/16” Thick. After developing, if the lead letter appears lightly, it indicates Back Scattering .If the Lead Letter does not appear, then there is no back scattering.

7.13 Number of penetrameters

Penetrameter shall be placed so that one is visible on each radiograph if the density of the radiograph through the length of the area of interest varies by place on the area of interest.

When more than one film is used for an exposure a penetrameter image shall be present in each radiograph expect where complete panoramic exposure is taken there equally spaced 3 penetrameter shall be placed at 1200 each.

7.14 Film Processing (Developing)

The Temperature of the dark room in which the film is processed shall be maintained 20°C and the Relative Humidity of the room should be 50-60%. A calibrated safe light (Red) of 15 Watts output shall be placed at a distance of 1.2 meters. Processing will be manual. Distance between each film must maintain 12.7 mm overlap. Agitation must be done with Stainless Steel Stirrer and stirring shall be done for 15 to 20 sec during each minute of developing to eliminate air void and to help development of film evenly.


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Normal developing time is 5 – 8 minutes at 200C. For developing, Solutions should be checked immediately before the immersion of films. Temperature below 200C will retard the action of the chemicals sufficiently to produce under development while excessively high temperature (above 220C) can soften emulsion on the film. Logbook for temperature and developing time shall be maintained.

7.15 Film Fixing

The hanger along with film is to be agitated at two minutes interval. We must agitate the films initially for minimum 45 seconds and 15 to 20 sec after subsequent interval to ensure uniform and rapid fixation fixing time will be 15 min (Approx). During fixing the temperature must be maintained between 190 to 210C.

8.0 Safety

Date & time of radiography to be taken should be informed to all concerned well in advance.

Radiation Warning symbols must be displayed at the location of the radiography places.

The area of radiography should be cordoned off. Flash lights to be displayed to caution the surrounding people and passer by.

Radiation Warning Slogans should be written legibly in English and the local languages and must be displayed at the location of the radiography places.

Before starting of radiography operation, visual check should be there about the surrounding and other agencies working nearby should be informed.

While doing radiography, dosimeter and survey meter must be available with people executing the radiography.


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Source strength should be known and accordingly barrication distance can be calculated

Before doing the radiography the available format to be filled by the radiographic agency and concerned site in charge and it has to be submitted to the Safety Department.

Safer Working Distance

The greater the distance from radiation source, the lower the exposure received. The safe distance from the radiation source will be calculated from the approved chart and the inverse square law is used to calculate radiation intensities at various distances from source

I1 D2

I D21

Where I and I1 are intensities at distance D and D1

- The End -

=


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02. Ultrasonic Testing Procedure.

CONTENTS

1. Purpose

2. Scope

3. Reference

4. Equipment

5. Equipment Calibration

6. Transducer

7. Couplant

8. Personnel Qualification

9. Surface Preparation

10. Calibration

11. Testing

12. Recording

13. Acceptance Standards

14. Rejection Level


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1. Purpose

Purpose of this procedure is to define the technical requirements and modes of operation to be met as well as the results to be obtained by the erector concerning the Ultrasonography Test.

2. Scope

The scope of this procedure is limited to Ultrasonic Testing to be conducted at 4,000MW Ultra Mega Power Project at Mundra Site.

3. References

ASME Boiler and Pressure Vessel Code , Section Ⅰ.

ASME Boiler and Pressure Vessel Code , Section Ⅴ.

ASME B31.1 Power Piping

ASTM E317.

4. Equipment

The ultrasonic instrument should be of pulse echo type having “A” scan presentation and should be capable of generating, receiving, amplifying and displaying high frequency electrical pulses usually from 1.0 MHz to 5.0 MHz.


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5. Equipment Calibration

Instrument shall be calibrated as per ASTM E317.

6. Transducers

Miniature Angle beam transducers with a frequency of 2 to 5 MHz shall be used. For thickness below 12 mm, 60° & 70° probe shall be used. For thickness above 12 mm, both 45° & 60° and 70° probe shall be used.

Straight beam transducers of diameter 10 to 25 mm with frequency of 2 MHz shall be used to check the base material

7. Couplant

Lubricating oils and grease shall be used as a couplant.

8. Personnel Qualification

The Ultrasonic Testing (UT) personnel shall be qualified and certified in accordance with a written procedure conforming to nationally recognized Non Destructive Testing (NDT) personnel qualifications practice such as SNT-TC-1A, BIS etc.


In general, weld reinforcement shall be properly dressed to avoid unwanted indication. All welding undercuts are to be ground, or filled and ground. Welding spatters are to be removed on the weld as well as adjacent areas of the weld.


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10. Calibration

10.1 Calibration block with side drilled hole shall be used as per section V.

10.2 Position the search unit such that 75% of amplitude signal is obtained from ¼ T hole of half skip distance.

10.3 Move the search unit to get the maximum signal from ½ T hole.

10.4 Move the search unit to get the maximum signal from ¾ T hole.

10.5 Move the search unit to get the maximum signal from 1¼T hole.

10.6 Mark the four points on CRT and connect these points by a smooth line. This line is called the DAC curve.

11. Testing

Mark the half skip distance and full skip distance on the job on either side of weld. Additional 6dB shall be given for scanning. However, for evaluating flaw, the gain at calibration shall be used. Move the search unit between half skip and full skip by giving slight oscillation. Each scanning pass shall overlap at least 10%.

Scanning shall be done with minimum two angles. Scanning rate shall not exceed 150mm per second.

12. Recording

Any indication exceeding 50% of DAC shall be marked.


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13. Acceptance Standard

Defect Indication

% DAC Material Thickness Length of Defect

Indication

Above 50% Up to 19mm 6mm

Above 50% Above 19mm and Up to 57mm 1/3 T

Above 50% Above 57mm 19mm

In any length of 12T the sum of aggregate of defect length should not exceed T where T is the thickness of lower plate used.

Distance between any two adjacent defects should not be less than the length of the larger defect otherwise both the defects are considered as single defect and defect length is considered totally including the gap between the two.

14. Rejection Level

Indications from cracks, lacks of fusion or incomplete penetration are unacceptable.

Any defect indication exceeding acceptance levels are considered as NOT ACCEPTABLE.

- The End -


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03. Magnetic Particle Examination Procedure.

CONTENTS

1. Purpose

2. Scope

3. Reference

4. Construction Equipments & Instruments

5. Examination Medium


7. Calibration of Equipment

8. Magnetizing Field Adequacy and Direction

9. Lifting Power of Yokes

10. Procedures

11. Demagnetization

12. Safety


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1. Purpose

Purpose of this procedure is to define the technical requirements and modes of operation to be met as well as the results to be obtained by the erector concerning the Magnetic Particle Test.

2. Scope

The scope of this procedure is limited to Magnetic Particle Test to be conducted at 4,000MW Ultra Mega Power Project at Mundra Site.

3. References

1) ASME SEC V, Article 7.

4. Construction Equipment and Instruments

A suitable and appropriate means for producing the necessary magnetic flux in the part shall be employed, using one or more of the techniques listed below

1. Prod Technique

2. Yoke Technique

5. Examination Medium

Dry Particles, which are finely divided ferromagnetic particles, are used for the examination. The color of the particles (dry powder) shall provide adequate contrast with the surface being examined.

Magnetic Particle Examination shall not be performed if the surface temperature of the part exceeds 600°F. The temperature of the part shall be check by using temperature sticks (Thermo chalk).


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Prior to Magnetic Particle Examination, the surface to be examined and all adjacent areas within at least one inch shall be dry and free of all dirt, grease, lint, scale, welding flux and spatter, oil, or other extraneous matter that could interfere with the examination.

Cleaning may be accomplished using detergents, organic solvents, de-scaling solutions, paint removers, vapor degreasing, sand or grit blasting, or mechanical cleaning methods.

If coatings are left on the part in the area being examined, it must be demonstrated that indications can be detected through the existing maximum coating thickness applied

7. Calibration of Equipment

Each piece of magnetizing equipment with an ammeter shall be calibrated at least once a year, or whenever the equipment has been subjected to major electric repair, periodic overhaul, or damage. If equipment has not been in use for a year or more, calibration shall be done prior to first use. The unit’s meter reading shall not deviate by more than ±10% of full scale, relative to the actual current value as shown by the test meter.

8. Magnetizing Field Adequacy and Direction

The Magnetic Particle Field Indicator shall be used to verify the adequacy or direction of the magnetizing field, by positioning that on the surface to be examined.

A suitable flux or field strength is indicated when a clearly defined line of magnetic particle forms across the copper face of the indicator when the magnetic particles are applied simultaneously with the magnetizing force.

When a clearly defined line of particles is not formed, or is not formed in the desired direction, the magnetizing technique shall be changed or adjusted.


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9. Lifting Power of Yokes

The Magnetizing force of yokes shall be checked at least once a year, or whenever a yoke has been damaged. If a yoke has not been in use for a year or more, a check shall be done prior to first use.

Each alternating current electromagnetic yoke shall have a lifting power of at least 10 lb at the maximum pole spacing that will be used.

Each direct current or permanent magnetic yoke shall have a lifting power of at least 40 lb at the maximum pole spacing that will be used.

Each weight shall be weighed with a scale from a reputable manufacturer and stenciled with the applicable nominal weight prior to first use. A weight need only be verified again if damaged in a manner that could have caused potential loss to the material.

10. Procedures

The Magnetic particle inspection consists of magnetizing the area to be inspected and then applying the magnetic particle to the surface of the test area. Magnetic flux leakage caused by cracks and other discontinuities will attract the magnetic particles and the resulting pattern will be characteristic of the type of discontinuities present.

Magnetization of surface shall be performed in two perpendicular directions with Sufficient over lap assure 100% coverage.

The dry powder shall be applied uniformly by a powder squeeze bulb.The method used for performing the examination shall be the continuous method. The current shall remain on during the application and removal of the excess particle from surface. The removal may be with light blow of air. Care shall be exercised so as not to disturb the particles adhering to a possible indication.

Prod Technique – Direct or rectified magnetizing current shall be used for Prod technique. The current shall be 100 amp/inch to 125 amp/inch of prod spacing for sections ¾ inch thick or greater. For sections less than ¾ inch thick, the current shall be 90 amp/inch to 110 amp/inch of prod spacing. Prod spacing shall not exceed 8 inch.


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Yoke Technique – This method shall only be applied to detect discontinuities that are open to the surface of the part. For this technique, alternating or direct current electromagnetic yokes, or permanent magnet yokes, shall be used. The current shall be 600 to 800 ampere per 3 to 4 inch yoke spacing.

11. Demagnetization

When residual magnetism in the part could interfere with subsequent processing or usage, the part shall be demagnetized any time after completion of the examination.

12. Safety

PPEs – Safety helmet, safety shoe, hand gloves are mandatory

Work permits to be obtained before start of work

Ensure the area is free from oil and grease

Ensure that no persons heart comes in contact with magnetic flux

Ensure that proper work instruction and pep talk is given to the work men on regular basis

- The End -


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04. Liquid Penetrant Examination Procedure.

CONTENTS

1. Purpose

2. Scope

3. Reference

4. Procedure


6. Application of Liquid Penetrant

7. Removal of Excess Penetrant

8. Development of Penetrant

9. Inspection

10. Post Cleaning

11. Safety


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1. Purpose

Purpose of this procedure is to define the technical requirements and modes of operation to be met as well as the results to be obtained by the erector concerning the Dye Penetrant Test.

2. Scope

The scope of this procedure is limited to Dye Penetrant Test to be conducted at 4,000MW Ultra Mega Power Project at Mundra Site.

3. References

ASME SEC V, Article 6.

4. Procedure

A liquid penetrant is applied to a surface to be examined; it penetrates into surface defects such as cracks or pinholes. The excess penetrant is wiped off and then developer is applied to the surface. By means of a blotting action developer draws out penetrate from defects giving an indication of the defect. This procedure consists of the following steps.

1) Surface preparation – cleaning

2) Application of liquid penetrant.

3) Excess penetrate removal-Primary Cleaning.

4) Penetrant removal by Cleaner Moistened Cloth-Secondary Cleaning.

5) Development of penetrant.

6) Inspection.

7) Post cleaning


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The surface to be tested shall be free of any dirt, grease, spatter, scale, slag, paint etc. This pre cleaning can be done by chemical and mechanical means. Using a chemical called cleaner which is a part of Liquid Penetrant Test kit does chemical pre cleaning. Pre cleaning by mechanical means can be done by using power tools such as buffing wheels or grinding wheels.

6. Application of Liquid Penetrant

The penetrant may be applied by spraying or brushing and area shall include the weld and adjacent base metal for at least ½ an inch on either side of weld. The temperature of the item to be examined shall be from 160 to 520C. The dwell time for the penetrate shall be a minimum of 5 minutes.

7. Removal of Excess Penetrant

The excess penetrant shall be removed from the surface after the required dwell time by first wiping with clean dry lint free cloth and then with cleaner moistened lint free cloth.

8. Development of Penetrant

The non- aqueous developer shall be applied by spraying. Before applying the developer the can shall be agitated by shaking. Care shall be exercised to avoid over spraying, which may mask indications. Developer must be applied by maintaining a distance of one foot from the surface of the weldment subjected to the testing.

9. Inspection

The interpretation shall be performed seven minutes after the application of the developer to a maximum of thirty minutes.


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10. Post Cleaning

Post cleaning shall be carried out after examination and it shall be done with lint free cloth/paper moistened with solvent.

11. Safety

PPEs – Safety helmet, safety shoe, safety goggles, Dust mask and hand gloves are mandatory.

Container shall be placed at least 20mtrs away from the source of ignition.

Ensure that cotton waste, cloth rakes etc to be removed after the work is completed.

Ensure that these waste are stored far away from source of ignition and send to dumping yard.

Ensure that work permits are obtained before start of work.


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Attachment.

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