Repair & Repair of Repair PQR

Date 11-15-2011 05:39 Edited 11-15-2011 10:41

If project specification request to performing qualification of repair & repair of repair regardless of QW-202.3 of ASME Sec.IX at process piping in gas field development & refinery plant, is it maening for each root repair,full repair,intermediate repair,cap repair and repair of repair should be done separately qualification?or at least with one full repair of repair will be coverd all of them so if for each original WPS it is defined sevaral PQRs for covering as per QW-451 of ASME Sec IX then regarding repair & repair of repair qualification is it required again to follow QW-451 or not?(It means for each test coupon must be performed qualification with 5 repair test coupuns including:root repair,full repair,intermediate repair,cap repair and repair of repair or not?).

By ozniek

Date 11-15-2011 12:45

Hi khodabandeh

The project specification that required you to qualify the 1st and 2nd repairs should specify what the repair tests should cover. If the project specification asks for a qualification for a root, intermediate & cap, and the same for the secod repair, then you will need to qualify 6 repair procedures. Also just make sure of the testing required for each type of repair, as this can also vary.

I do not understand the difference between "root repair" and "full repair". Can you explain that to me? Also, what material is this? (Duplex Stainless Steel?)

Regards
Niekie

By khodabandeh (**)

Date 11-15-2011 14:15

Dear Niekie,
Your respond is yes in our project Duplex Stainlesss Steel exists also we have the another materails such as Cupronickel,Alloy Steel,Stainless Steel .Here for big size pipes it is possible to repair from inside of the pipes therfore root repair is meaning partial repair at root from inside of the pipes.Please explain me each test copun as per QW.451 should be qualidfied same as original PQR or only one of the coveing thickness of PQRs test coupon including 6 types of repair is enough?

By ozniek

Date 11-16-2011 12:23

Hi khodabandeh

Ok thanks, now I understand the "root repair" test requirement. This then means that you will need 8 repair PQR tests to be performed. (This is a very stringent requirement, and I believe it is way over the top, but if the client is happy to pay for it, then give him what he wants!)

Regarding the rest of your question, I believe you are asking me if you must perform the same tests on each of the repair coupons as that performed on the original PQR coupon. (Tell me if I have mis-interpreted this.)

The short answer is that seeing as this repair testing requirement is not a code requirement, but a client specification requirement, this answer should be in the client specification. (If it is not, submit a technical query to the client asking for clarification.) My experience (and this may be different for your spec, so check it!) is that normally the same testing is required for the repair coupons as for the original PQR, with slight modifications such as positions for hardness scans or impact test notches. The exception being that for the surface repair coupon, normally only hardness testing is required.

As a general rule, the repair coupons will be made on the same size of coupon that was used for qualifying the original weld PQR.

Hope this helps.

Regards
Niekie

By khodabandeh (**)

Date 11-17-2011 03:14

Dear Niekie,
I appreciate you,I mean the number of the test coupons which have been used as supporting PQRs for each WPSs according to QW.451of ASME Sec.IX again to be followed for each type of repair or performing all type of repairs with one size of the PQRs will be coverd?In project specification is not mentined that so it is not cleard for me.(Also it is not mentined any more regarding type of test requirement in project specification maybe type of the test is similar with original PQRs).

By js55

Date 11-17-2011 13:44

Again, in the context of a repair of a repair for duplex QW-451 ain't gonna get it done.

By js55

Date 11-16-2011 12:45 Edited 11-16-2011 12:47

If your doing a repair of a repair on duplex, depending upon the grade, you probably have nothing left but a paper weight anyhow. Too much time at sensitive temps. I would not be surprised if the qualification for repairs involved more than the usual Section IX type mechanicals because this won't reveal the manner in which the material is destroyed.

By ozniek

Date 11-16-2011 13:52

Hi js55

Most client specs that I am involved with in the petro-chem field will ask for corrosion testing of Duplex Stainless Steel coupons, (Normally ASTM G48 pitting tests) and also ferrite count testing which includes micrographs looking for sigma phase and other intermetallics. If you have messed up the microstructure, then normally these tests will show it, although they are by no means infallible. These tests will be particularly important for the repair procedures.

Regards
Niekie