Change of Electrodes

Date 05-29-2003 13:12

As long as the contractor has a properly qualified WPS (covering the materials of your vessle) he does not have to requalify the WPS under the rules of Section IX.

However, Section IX makes a number of statements about the appropriate selection of filler metals to suit the metallurgical properties of the weld. There may be a more appropriate filler metal for the application you are referring to. As the client, you have a right to specify what filler metal you want the contractor to use. If you want the contractor to use what was originally used, he will have to run another PQR because the alloying elements have changed byond what is allowed (indicated by the suffix B2 vs C1, which are chrome and nickel based respectively).

If another PQR is needed simply to qualify the filler metal (due to a change in the A number), it will not effect the welders certifications.

Charles Hall

By JINX

Date 05-29-2003 16:39

As chall stated there is a difference in chemistry with both suffix.
B2 has 1.00-1.50% cr. and 0.0% Ni.
C1 has 0.0% cr. and 2.00-2.75% Ni.
To choose the proper WPS/PQR we should consider the chemistry of the base material, and what type of enviroment does this vessle experience during service. If you could provide additional information that would be helpful.

By mmaxwell8 Date 05-29-2003 17:07

The base material is SA537 CL2. The vessel is rated for 137.7 psig at 400 F. What we're attempting to due is repair cracks in the original structural welds. The vessel was constructed using E8018-C1. The contractor has a "certified" procedure using SA537 CL2 with an E8018-B2. I am asking that he use the E8018-C1 to match the original construction. The issue is whether he needs to recertify his procedure for the new electrode. Time is an issue, but as always...safety first.

Thanks for the timely reply...

By chall

Date 05-29-2003 17:52

The first issue is whether 8018-B2 is suitable for the base metal. The answer is yes. There may be a better choice, but this is an acceptable filler.

The original manufacturer used an alternative that is also acceptable.

The strict answer to your question is yes he has to requalify the WPS in order to use 8018-C1.

The last part of the question seems to be: Is it acceptable to do a repair using 8018-B2, over a weld that was 8018-C1? Without having a good technical basis for my answer, I would say: no. I know the area of interface between the base metal, existing weld and new weld would produce a dilution that may be ok in service, but I would still run another PQR for the different filler metal.

If time is a factor, (if I was comfortable with our welder), I would do the following:

Complete the weld using 8018-C1, write an NCR pointing out the need to qualify the different filler, run the PQR and (assuming the PQR passes), clear the NCR. If the PQR doesn't pass, you will have to put a hold on the component.

Doing another PQR should not take more than a couple of days (to complete the welding, machine work and destructive tests) once the material is in hand.

Charles Hall