prequalified and repair

Date 01-19-2009 12:49

Do you have a weld procedure?

It depends on what you need. A standard repair procedure for the old MIL-STD-1261 military specification is...

1. Method used to remove defect (grind, machine, thermal, etc.).
2. Contour of Cavity (60*-90*). (How deep you grind.)
3. Method of Intermediate Inspection (Visual, Liquid Penetrant, etc.)

The repair procedure is part of the weld procedure.

Keith

By doyenofcastle (**)

Date 01-19-2009 14:45

to make it clear for exampleI have prequalified WPS for 2G , this not included repair but I've defect in 2G weld ,can I use this to make the repair and write in my report I used this PWPS to repair

By hogan

Date 01-19-2009 15:38

doyenofcastle,
I typically use BC-P2-GF with a written procedure dealing with the any unique requirements. This will include some of the following: preheat prior to gouge, gouge/grind max depth, preheat, any NDT (MT root), final surface condition (grind flush), and any final NDT.

By MBSims

Date 01-19-2009 16:37

If the weld was made with a prequalified WPS, I believe it would be acceptable to make the repair using the same WPS. D1.1 does not appear to address this situation though. The most relative paragraph appears to be:

5.4.6 Repairs. Welds having discontinuities prohibited
by Section 6, Part C shall be repaired as allowed by 5.26
utilizing a qualified welding process, or the entire weld
shall be removed and replaced.

The words "qualified welding process" imply a "qualified" welding procedure, but their intent is not clear. SMAW, SAW, GMAW (except GMAW-S), and FCAW are considered "prequalified" processes when all of the applicable requirements of Section 3 are met. Section 3 refers to the prequalified joint details, but does not address joint preparation for repairs. Paragraph 5.26 also does not discuss whether a prequalified or qualified WPS may be used. I believe if you are using the same WPS used to make the weld originally and following the requirements of 5.26, a "prequalified" WPS is acceptable.

By hogan

Date 01-19-2009 16:50

MBSims,
As long as all of the requirements of the original wps requirements are met, then the same wps can be used. Although, it is difficult to hold the joint dimensions of the original wps when making a repair.

By MBSims

Date 01-19-2009 22:29

Obviously it depends on the depth and degree of repair required. It would clearly be acceptable to repair undercut or underfill using the same WPS. A repair cavity that is deeper could be looked at as being similar to a weld in progress, and using the same WPS would not present a problem. A through-wall repair would require re-establishing the specified root opening and joint geometry, although the ends of the cavity would typically be tapered up to the surface. In any case, D1.1 does not appear to address repairs in that level of detail and does not specifically prohibit the use of a prequalified WPS for repairs.

By 803056

Date 01-20-2009 07:22

You didn't describe the nature of the repair, but D1.1 does include "standard repairs" for problems with weld profiles and cracks (see Clause 5.26). It provides direction on how to repair a crack, i.e., the extent of excavation (see Clause 5.26.1.4).

If you can meet the requirements of a prequalified weld, there is no reason not to use a prequalified procedure to facilitate the repair. If you comply with the requirements of Clause 3 (use Annex H, "Contents of Prequalified WPS" as quick review of the requirements (I'm looking at D1.1-2004 because its sitting on my desk), you should have no need to qualify a WPS by testing per Clause 4.

Best regards - Al