COMPANY NAME

WELD REPAIR PROCEDURE FOR CARBON STEEL

FORM-73

This procedure shall be referred when the unsound metal o weld defects are found of visual examination, and or NDT methods.

Rev.

(Rev. 1 Ref

WELD REPAIR PROCEDURE

(CARBON STEEL)

1.0SCOPE

This is a method statement defining all the necessary steps leading up to the completion of a weld repair for Carbon Steel piping only.

2.0REFERENCES

No 1

No 2

No 3

3.0PROCEDURE

3.1Identification and marking.

3.3.1It is the responsibility of the NDT Coordinator to give the Repair Crew accurate and complete information regarding the type, location and depth defect(s). The information will include the following:

a)Request for weld repair RWR (sample attached).

b)Tracing of repair area from the radiograph.

c)Markings on the pipe surface showing the repair are. The repair Crew should remove either side of the indicated repair area a minimum of 25 mm to ensure complete removal of the defects.

3.2Root Repairs.

3.2.1Root repairs shall be done from inside the pipe wherever there is access by backwelding.

In such cases, for safety purposes, adequate ventilation will be provided inside piping during the repair welding a responsible person will be on stand by during this period. If no access will be available to the inside, than the welding will be ground from the outside using 4’’ grinder with 3 disc. To cut open the root for the removal of defect(s).

The root gap repair and configuration of the ground repair area will, as far as practicable, be the same as the WPS requirements.

3.2.2Welding should proceed as per the approved Welding Procedures Specification.

3.2.3In case of cracks, after grinding, the area will be DP/MPI tested to ensure complete removal of the crack prior to reweld.

Linear defects and porosities open to surface and subsurface can be detected by penetrant test and magnetic Particle Testing methods.

Defects noted for repair during Radiographic Inspection will be re-radiographed after repair for final acceptance and record.

Penetrant test and Magnetic Particle Tests will be done to ensure the correct method of removal or defects by grinding.

3.3Repairs above the roof.

3.3.1In such repairs, grinding can be done using large discs if the repair area is long.

3.4Upon completion of the repair by the Repair Crew, the RWR will be returned to QC with the date of the repair marked. This information will be processed by the NDT Coordinator in order to re-radiograph the repair area and clear the weld for release.

3.5Two repairs can be performed in a specific area of a weld joint. If after the second repair the RT results are not acceptable, the weld joint will be cut out.

3.6In cases where the type and extent of defect is such that repair is not practical, the weld joint will be cut out. The decision for cut out will be taken by the QA/QC Department.

3.7All repairs will be performed by qualified Welders who have a good performance record.

3.8If the thickness of run pipe is above 19 mm which is subjected to PWHT, in case of delayed heat treatment, the repaired weld joint shall be immediately heat treated to 300 C and held at that temperature 20 minutes; and wrapped with Insulation Blanket (Asbestos Cloth) for allowing slow cooling, as per GES-012-51 [6.2-Para (12)], and PWHT will be carried out as per approved PWHT procedure record No. 001 dated 14.4. 1992.

COMPANY NAME

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REQUEST FOR WELD REPAIR

/ No. :
Date :
NO. / DRAWING NO. / WELD NO. / RT NO. / REPAIR INFORMATION / REPAIR DATE