Welding procedures?

[Bluedata]

Is it ok to repair a 10" S40 CS A53-B pipe that was welded with 7018, with 70S Tig on the Cap? I was not given a Procedure for this Inspection, and was told that it was ok. I would like to know for sound of mind……

 

[metengr]

It is technically acceptable to do but do you have the welding procedure specification for doing this repair sequence?

 

[Duwe6]

Any GTAW weld procedure, if it has adequate "big-T" qualified base metal thickness will work for this repair. Main Inspx points are FULL excavation of the defect, and a wide enough groove angle to be weldable. Angle should be on the GTAW WPS being used.

 

[deco0404]

I would have thought that unless you have a qualified repair procedure using TIG as a substitute for SMAW you cannot do this. Change of process is an essential variable in any spec.

 

[Duwe6]

Almost any GTAW procedure will work. Just have to watch 'big'T versus 'little' t as set in your GTAW WPS.

'Big'T is the total thickness of the basemetal being welded on. Does the proposed WPS have a thick enough upper limit to allow work on your thickness?

'Little' t is the total deposited weldmetal. Do not use this when evaluating whether your WPS will work for the repair. And again, ensure that the angle & width of the excavation is wide enough to fulfil the requirements of your WPS. Welders tend to leave the groove too narrow to meet the limits of a WPS.

 

[Guest102023]

This kind of question is why I dislike combining GTAW & SMAW on PQRs ...