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DOC. NO.: 04 RADIOGRAPHIC TESTING ISSUED : January 2001

REVISION : 0PROCEDURE

PAGE :

PROCEDURE FOR RADIOGRAPHIC TESTING OF WELDS IN

STRUCTURAL STEEL FABRICATION

as per

AWS D1.1

0

REV. NO. DATE APPROVED BY :

LEVEL III

APPROVED BY : APPROVED BY :



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PROCEDURE FOR RADIOGRAPHIC TESTINGOF WELDS IN STRUCTURAL STEEL FABRICATION

(AWS D1.1)

TABLE OF CONTENTS

Description Page No.

1.0 Scope 4 of 35

2.0 Reference 4 of 35

3.0 Definition 4 of 35

4.0 Personnel Qualification 5 of 35

5.0 Radiographic Equipment 6 of 35

6.0 Preparation 6 of 35

7.0 Location of Datum 6 of 35

8.0 Cassettes 7 of 35

9.0 Film 7 of 35

10.0 Screens 8 of 35

11.0 Geometric Relationship 8 of 35

12.0 Image Quality Indicator 9 of 35

13.0 Sensitivity 11 of 35

14.0 Film Density 11 of 35



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TABLE OF CONTENTS CONT’D

Description Page No.

15.0 Scattered Radiation 11 of 35

16.0 Radiographic Procedure 12 of 35

17.0 Film Processing 14 of 35

18.0 Film Identification 14 of 35

19.0 Viewing Conditions 14 of 35

20.0 Interpretation of Radiographs 15 of 35

21.0 Radiographic Reports 15 of 35

22.0 Safety 15 of 35



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1.0 SCOPE

This procedure describes the radiographic method to be employed by the company for the Radiographic Inspection of butt welds in accordance with AWS D1.1.

2.0 REFERENCES

AWS D1.1 Section 6DIN 54109 - Wire Type Image Quality Indicators

3.0 DEFINITION

a. Client Company or organization for whom Global Inspection Services performing the work.

ASNT The American Society for Non Destructive Testing

PCN Personnel Certification for Non Destructive Testing

CSWIP Certification Scheme for Weld Inspection Personnel

IQI Image Quality Indicator

3.0 PERSONNEL QUALIFICATION



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Radiographic Inspection work shall be carried out by at least one Radiographer and one Assistant Radiographer. Each technician shall be required to hold the following:-

a) Radiographer A valid LPTA Radiographic Operator License

and a current Certificate of Proficiency in Radiography Level II to a recognized qualification and certification scheme.

b) Assistant Radiographer Registration with LPTA as a Radiation Worker and a current Certificate of Proficiency in

Radiography Level I or Level II to a recognized qualification and certification scheme.

c) Radiographic Interpreter A current Certificate of Proficiency in Radiography Level II, Level III or Radiographic

Interpreter to a recognized qualification and certification scheme.

The following recognized qualification and certification schemes may be used for the purpose of qualification and certification of personnel:-

a. ASNT (in accordance with the company’s Written Practice).

PCN / CSWIP

5.0 RADIOGRAPHIC EQUIPMENT



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For Gamma Ray work, Tech Ops 660 or equivalent containers and remote control windout will be used.

6.0 PREPARATION

Radiographic Inspection shall only be carried out on weldment which has visually inspected and any remedial work necessary is completed and accepted by the cistomer. In addition, the Radiographer inspects the weld surface for any irregularities that may mask or confuse interpretation of the final radiograph.

7.0 LOCATION OF DATUM

All weld will be positively marked datum and each portion under examination shall be positively identified by marking along the length of the weld.

This may be achieved by taking measurements along the length of the weld from an agreed datum. For tubular structure, the ‘clock face’ method shall be employed and the datum line shall be positioned, as follows:-

a) For horizontal and inclined tubular structure, the datum is the highest point in the joint when viewed from the lower numbered joint.

b) For vertical tubular structure, the datum is north when the joint is viewed vertically downwards.

In all cases the datum shall be indelibly marked on the welds. A meter band incorporating lead numerals along the welds shall be utilized to allow positive location of any discontinuity.

8.0 CASSETTES



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Flexible envelope cassettes shall be used unless specifically stated otherwise. Ensure close film to screen and cassette to object contract.

The use of pre-pack film with integral metal screens may be used with written agreement from the Client.

9.0 FILM

9.1 Type of Film

Radiographs shall be made using industrial radiographic film and shall be selected from Table 1 below.

Table 1 : Selection of Radiographic Film

Class of Film Brand TypeI

(high sensitive film)Dupond

AgfaKodak

NDT 55D4MX

II(sensitive film)

DupondAgfa

Kodak

NDT 70D7CX

Films shall have sufficient length and shall be placed to produce at least 13mm of film exposed to direct radiation beyond each free edge where the weld is terminated.

9.2 Overlap

If more than one films is required in single exposure, overlapping cassettes shall be used. Radiographs shall have 25mm overlap at each end to ensure that no portion of the joint remains unexamined. There shall be a specific lead marker visible on both radiographs in the area of overlap.

10.0 SCREENS



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Lead intensifying screens shall be used. The front screen thickness shall normally be 0.125mm and the rear will normally be 0.125mm.

Screen shall be examined on a regular basis for dirt or blemishes which may transfer onto the film thus causing confusion with and masking of defect images.

11.0 GEOMETRIC RELATIONSHIPS

11.1 The geometric unsharpness is calculated as folows:-

Geometric unsharpness, Ug = f x dS - d

Where : f is the Focal Spot Size of Source Sized is the Object-to-Film DistanceS is the Focal spot-to-Film Distance (X-ray) or source-to-film distance (Gamma Ray).

11.2 Geometric Unsharpness of the radiograph shall not exceed the Ug value in Table 2 below:-

Table 2 : Maximum Geometric Unsharpness

Material Thickness, mm Ug Maximum, mmUnder 50.8

50.8 through 76.250.9 Over 76.2 through 101.6

50.10 Greater than 101.6

0.510.761.021.78

Material thickness is the thickness on which the penetrameter is based. This shall be the base metal or parent metal plus the maximum allowable reinforcement. For welds at transition thickness, material thickness shall be the thinner base metal.

12.0 IMAGE QUALITY INDICATORS

12.1 Selection of IQI



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The IQI provides a guide to the quality of radiographs produced and shall be appropriately chosen from one of the types recommended in DIN 54109 (Table 3).

Table 3 : DIN 54109 Wire Type IQI Designation

Penetrameter Designation

Wire Number Wire Diameter, mm

1 - 7

1234567

3.2002.5002.0001.6001.2501.0000.800

6 - 12

6789101112

1.0000.8000.63000.5000.4000.3200.250

10 - 16

10111213141516

0.4000.3200.2500.2000.1600.1250.100

a) Source Side Penetrameter(s)

The penetrameter(s) shall be placed on the source side of the part being examined, except in the condition described in 12.2b).

b) Film Side Penetrameter(s)

Where inaccessibility prevents hand placing the penetrameter(s) on the source side it shall be placed on the film side in contact with the



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part being examined. A lead letter ‘F’ at least as high as the penetrameter identification number(s) shall be placed adjascent to the penetrameter(s).

Radiography shall be performed with a technique of sufficient sensitivity to display the penetrameter image and the designated or smallest wire for required sensitivity which are essential indications of the image quality of the radiograph. The radiographs shall also display the identifying number and letters.

12.2 Number of Penetrameters

IQI shall show clearly on each radiograph. For a radiograph represents 255mm or greater of weld length, two IQI shall be placed; one at each end of the weld length. For radiograph represents less than 255mm of weld length, one IQI shall be placed at any end of the weld length. IQI shall be perpendicular to the joint with the smallest wire on the outer edge of the area being radiographed.

Figure 1 and Figure 2 illustrate the arrangement of IQI(s) locations.

For tubular structure, the following exception minimum number and required locations of IQI shall be followed:-

a) Where the source is located at the center of the tubular structure and one or more film holders are used for a single exposure of complete circumference (Panoramic Technique), at least three penetrameters shall be spaced approximately 120 apart.

b) Where the source is placed at the center of the component (Single-Wall Single-Image Viewing) and four or more film holders are used for a single exposure of a section of the circumference, at least three penetrameter shall be used. One penetrameter shall be in the approximate center of the section exposed and one at each end.

c) Where the source is located on the axis of the object (Double-Wall Single-Viewing Technique) and four or more film holders are used for an exposure of a circumferential weld, at least three penetrameters shall be used. One penetrameter shall be in the approximate center of the section exposed and one at each end.



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13.0 SENSITIVITY

The required sensitivity for each radiograph using DIN 54109 Wire IQI is as per ASME V Table T-276. DIN 54109 Wire Type IQI Sensitivity is calculated using the following formula:-

IQI Sensitivity= Diameter of Thinnest Wire Visible on Radiographx 100% Thickness of Penetrated Material In Same Region

14.0 FILM DENSITY

For each radiograph made, film Density will be measured in the area of interest and shall be not less than 1.8 and not greater than 4.0 in density.

15.0 SCATTERED RADIATION

Wherever necessary 6mm thick lead sheet shall be placed behind the film cassette to prevent scattered radiation from fogging the film.

The cassette shall have a lead letter ‘B’ a minimum of 12.5mm high, fastened to the back and if a light image of the letter appears on the film, additional backing sheets are required. A light image of the letter ‘B’ shall be cause for rejection of any radiographic film.

16.0 RADIOGRAPHIC PROCEDURE

Radiographic Inspection techniques shall be carried out in accordance with the current edition of ASME Section V Article 2.

A single-wall exposure technique shall be used for used for radiography whenever practical. When it is not practical to use a single-wall technique, a double wall technique shall be used.

16.1 Single-Wall Technique

In the single-wall technique, the radiation passes through only one wall of the weld (material), which is viewed for acceptance on the radiograph. An



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adequate number of exposure shall be made to demonstrate that the coverage has been obtained.

Figure 3, Figure 5 and Figure 6 illustrate the single wall technique, one of the following double wall technique shall be used.

16.2 Double-Wall Technique

When it is not practical to use a single wall technique, one of the following double wall techniques shall be used.

16.2.1 Single-Wall Viewing

For material and for weld components, a technique will be used in which the radiation passes through the two walls and only the weld (material) on the film side wall is viewed for acceptance. An adequate number shall be made to demonstrate that the required coverage has been obtained.

Where complete coverage is required for circumferential welds (material), a minimum of three exposures taken 120 to each other shall be made.

Figure 7 illustrates the double-wall exposure single-wall viewing set-ups that may be used.

6.2.2 Double-Wall Viewing

For materials and for welds in components 3-1/2 inch or less in nominal outside diameter, a technique will be used in which the radiation passes through two walls and the weld (material) in both walls is viewed for acceptance on the same radiograph. For double wall viewing only a source side penetrameter shall be used. Care will be exercised to ensure that where the required geometric unsharpness requirement cannot be met. Then the single wall viewing shall be used.

a) For welds, the radiation beam will be offset from the plane of the weld at an angle sufficient to separate the images of the source side and film side portions of the weld so that there is no overlap of the areas to be interpreted. When



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complete coverage is required, a minimum of two exposures taken 90 to each other shall be made for each joint.

Figure 8 illustrates the double-wall exposure double-wall viewing set-ups (ellipse) that may be used.

b) As an alternative, the welds, the radiation beam positioned so that the images of both wall are superimposed. When complete coverage is required a minimum of three exposures taken at 60 or 120 to each other shall be made for each joint.

Figure 9 illustrates the double-wall exposure double-wall viewing set-ups (superimpose) that may be used.

c) Additional exposures shall be made if the required radiographic coverage cannot be obtained using the minimum number of exposures indicated in (a) or (b) above.

17.0 FILM PROCESSING

This shall be carried-out in accordance with the recognized good practice. Processing shall be carried-out using the standard developer and fixer solutions and shall be in accordance with manufacturers recommendations.

The performance of the processing will be checked daily using control strips of X-ray film exposed to known density and processed. From the developed film, a check is taken and any density change is marked on a process control chart. Upper and lower limits are marked on the chart to provide controls against which the plot can be monitored. The results are interpreted and corrective action taken if necessary.

The radiographs will be free from imperfections due to processing or any other defects which would interfere with interpretation.

18.0 FILM IDENTIFICATION

Each film will be identified by the use of lead symbols to indicate the following minimum information:-



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a) The job or work pieceb) The jointc) The section of the jointd) The date of the teste) The welders identification

19.0 VIEWING CONDITIONS

The radiographs shall be examined in a darkened room. The radiograph viewer shall provide a light source sufficient for the essential IQI wire/hole to be visible for the specific density range. The light from around the outer edges of the radiographs will be masked.

20.0 INTERPERTATION OF RADIOGRAPHS

A calibrated densitometer or calibrated density strip will be kept in close proximity to the viewer and a ‘spot’ high density illuminator will be available. All comments with regard to film quality and interpretation will be recorded on the film folder and on the radiographic report form.

The density of density strips and densitometer calibration shall be verified by comparison with a calibrated step wedge film traceable to a national standard. The densitometer shall be calibrated in accordance with paragraph 5 of ASTM E-1079, Calibration of Transmission Referencing Code section.

21.0 RADIOGRAPHIC REPORT

Written reports shall be prepared giving the results of all the tests performed using the companies Radiographic Form.

22.0 SAFETY

All radiographic work will be carried out in accordance with Statutory Safety Requirements and with the companies Radiation Protection Program.

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