ASME Sect. IX Weld Joint Repair

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We are in the midst of a debate over weld repair and I would appreciate feedback on the situation.Welds were made to pipe and weld neck flange using a qualified procedure for robotic GMAW of a butt joint using a copper backer.  The weld subsequently failed X-ray for lack of penetration at the root.  We would like to back gouge the entire failed root and repair using GTAW by hand.We do not have a qualified WPS for hand GTAW only on this diameter, nor do we have one for GTAW root/GMAW filler either by hand or robot for this diameter.       One opinion is that a new WPS must be qualified for GTAW at the as welded diameter, or that a new weld procedure for hand GTAW/robot GMAW must be qualified in order to have the final repaired joint qualified either using combined procedures or a single procedure.        The alternate opinion is that no new weld procedure is required and the weld is acceptable based on the passing of the X-ray of the repaired joint.  Who’s right?Last edited by jimboux; 09-15-2011 at 01:00 PM.
Reply:ASME welding must be done in accordance with a qualified procedure.  If your existing procedures do not permit welding with GTAW within the limitations of QW-256, then you can't argue that the weld is acceptable based on the premise that an unqualified WPS produced a repair that passed NDE.  I'm not sure why diameter is the big concern, as base metal thickness is the governing essential variable, but if you have a hand GTAW PQR that supports the repair depth, you should be able to write a single-process GTAW WPS using existing qualifications that would cover your work scope.
Reply:The diameter comes into it in so far as the GTAW PQR coupon and the limits defined within QW-452.3
Reply:QW-452.3 does not apply to procedure qualifications, only performance qualifications.
Reply:Hmm, I guess I misunderstood the code - thanks for pointing that out, I'll have to go and review it again.
Reply:If the vessel is new construction, you must have the proper TIG procedure per Section IX.  However, if the job is being performed as a repair to NBIC, it is possible to use one of the SWPS that are published by AWS, since many of them are approved for NBIC use.If you would let us know if this is a repair, I will try to direct you to the appropriate SWPS.  It might save you some money.