Weld repairs need to do PQR test?

Date 10-06-2012 15:35

Depending upon EXACTLY how the PQR was run, tested, and written it should really cover you. It is the WPS that may need to be re-written. We generally have a WPS that specifically covers the 'Repair' operation as that is slightly different from the original weld procedure including backgouging (rather air arc, grinding, machining, torch, etc) to get rid of the discontinuities that made the weld rejectable and requires repair to make it acceptable (see a previous thread somewhere on here going through all of that discussion).

In essense you mentioned two separate operations in your question: WPS and PQR. So to reinforce my first paragraph, the PQR should cover you as long as it is for the same process and materials but you may indeed need a different WPS which is written from the PQR you already have to cover the repair procedure.

Have a Great Day, Brent

By 803056

Date 10-06-2012 17:29

Few welding standards require a repair WPS that is qualified by testing. Some project specifications may require a WPS be written to address a specific repair, but rarely require qualification by testing.

A QC person making a claim and referencing the code should be able to reference the specific clause or article that requires qualification by testing. If he simply says it is in the code, tell him you cannot find it and would like him to point it out. If he can't, he is simply blowing smoke.

There are certain base metals that are time at temperature sensitive (think heat treated aluminum alloys such as our favorite, 6061-T6), but that isn't the case if the base metal is an iron based alloy. Since most welding standards are written with carbon steel or high strength low alloys systems in mind, the time at temperature isn't a consideration or concern.

If the project is under the auspices of ASME B&PV Code, heat treatment is an essential variable, but I know of no case where removing weld using a CAC-A or OFC is an issue because that isn’t considered to be PWHT. The code will have something to say if the WPS was qualified with PWHT and you remove weld metal and reweld the original production weld after it was PWHT.

If the work must meet D1.1 there is a restriction when using an OFC on quenched and tempered steel.

Best regards - Al

By welderbrent (*****)

Date 10-06-2012 18:04

Noted, and I guess I didn't really explain myself fully Al. I was just expressing that since he did already have a PQR any inspector telling him he needed a new one was off base on that subject alone. Then, while one may want a separate WPS for the repair, there is no PQR required for it which seems to be where he said the inspector was going with the objection to using what was already in place.

I still feel like I'm as clear as mud... Oh well. I'll just leave it alone.

Have a Great Day, Brent

By 803056

Date 10-06-2012 19:53

I believe we are on the same page Brent.

I agree, a separate PQR isn't usually required unless there is more to the story than what we are being told.

Best regards - Al

By S. WINAI (**)

Date 10-07-2012 01:40

Hi thanks Brent and Al Moore,

More information contract specifield: All structure welding shall be in accordance with AWS D1.1 and ABS rules, latest edition.
So if i have PQR (FCAW-G)qualified with ceramic backing. Then WPS mention Back gouging (with/without). This WPS can cover repair procedure on this contract specifield?

Thanks,

S. Winai

By 803056

Date 10-07-2012 01:52

A separate WPS for repairs is not required per AWS D1.1.

A WPS qualified with backing is also qualified for welds that are back gouged.

That being said, I typically include a paragraph on typical repairs and how they are to be accomplished in the WPS used for production. I usually specify a visual examination of the excavation to verify the discontinuity is completely removed to sound metal. If the initial repair is not successful I typically require the inspector to make an assessment of condition and verification the defect is completely removed per D1.1. If the second repair is unsuccessful the matter must be bought to the attention of the Engineer. That isn't a code requirement, it is a requirement that I incorporate into the WPS and/or the project specification.

Best regards - Al

By welderbrent (*****)

Date 10-07-2012 15:33

Not that Al's explanation needs my 'second' but I second his post.

Simply put, Yes, that WPS covers what you are doing. That is, providing you have a properly filled out WPS in the first place and we have not missed something since we have not seen the actual WPS. A PQR with backing can support a WPS with/without backing which is plenty good for your repair.

I, like Al, use a separate 'Repair Procedure' description. Mine includes a separate WPS that is very specific for a couple of repair procedures with backgouging as well as the process that will be used to replace/repair the removed discontinuity material.

Have a Great Day, Brent

By 46.00

Date 10-07-2012 16:18

Brent, I'm sure you meant defect and not discontinuity?

By welderbrent (*****)

Date 10-08-2012 13:28 Edited 10-08-2012 13:34

According to all the assorted AWS references, as was discussed in another thread not very long ago, it is a discontinuity rather it is rejectable or not. And it's acceptance/rejection standards are determined by the applicable code for the project at hand. So, in my current wording it would only apply to the rejectable aspect of a discovered discontinuity, but it is a discontinuity. As a rejectable discontinuity it is subject to repair which would then take you to where we are in this thread discussing the application of a particular WPS to the work being performed with a qualified PQR for the materials and processes in use. If it were not a discontinuity it would not have received any attention at all. But it was found, decided to be rejectable, and in process of being repaired.

I'll see if I can find the other rather lengthy thread on discontinuities and attach the link.

Have a Great Day, Brent

edit: http://www.aws.org/cgi-bin/mwf/topic_show.pl?tid=30842

This is the main one of recent discussion. If you enter 'discontinuities' into the 'Search' function you will find many more.

By Shane Feder (****)

Date 10-09-2012 00:16

Hi Brent,
I think I see where 46.00 is coming from - if it is considered a discontinuity and not a defect why would you replace / repair it ?

I am a little mystified as to how a PQR with backing supports a WPS with or without backing ?
Cheers,
Shane

By 46.00

Date 10-09-2012 01:22

Brent, Interesting link although it does seem to have gone off topic quite a bit!

I am far from converse with D1.1, having only been exposed to it these past couple of years. However, I interpret AWS A3.0, and it is my own interpretation, slightly different.

Why would you repair a discontinuity, which may or may not be rejectable or even a flaw, when you can repair a defect, which as AWS A3.0 clearly states "The Term Designates Rejectability"?

By Nalla

Date 10-09-2012 21:49

Hi, Winnai
Method of Statement attached with existing applicable WPS/PQR will be enough, unlesss Contract Specification already call for it.
AWS D1.1 - does not call for separate PQR Qualification.
Pls take note essential and supplementary essential ( if CVN required ) compliance is mandatory
Thanks