ASME and DNV supplemental charpy test requirement
ASME and DNV supplemental charpy test requirement
(OP)
Help! We have almost passed our welding procedure to satisfy DNV and ASME requirements at -50F... but I have to redo the charpy testing. A couple of questions for the welding/ASME/DNV savvy out there:
1. We have a weld procedure that passed most areas: Vickers Hardness, Tensiles, Bends. The problem is that it failed in Charpy testing - in the base metal..*sigh*. Further testing of the base metal revealed it is a poor choice for -50F testing (9/10/10 ft lbs at -50). Funny, the MTR shows 65,68,75 at -50F.. As a result we are getting a new test coupon sent to the lab to confirm its properties BEFORE welding... The question is, can I just do a charpy test on the new coupon, to supplement the original test? Or, do I have to do the entire process over to requalify the PQR and subsequent WPS? It has to satisfy ASME and DNV... The original plate is 2.75" thick. If I can do a supplemental, does it have to be a 2.75" thick plate as well or can I use a 2.5" plate?
2. I used SA-516 Grade 70 (P1 Group2) to SA-516 Grade 70 for the coupons. Can I use SA-537 class1, 2.75" thick, instead - which has bettere impact properties? If I can do a supplemental, does it have to be the same material, or just the same P number and Group number?
3. Finally, I used a 2.75" thick coupon because all 3 welding folks I have talked to cannot agree that a 1.5" thick coupon will qualify up to 8". The production weld is 5" thick, using SA516 Grade 70. Impacts are required (15/12).. Can I do it with a 1.5" thick coupon, or am I limited to 2t?
Thanks in advance!
1. We have a weld procedure that passed most areas: Vickers Hardness, Tensiles, Bends. The problem is that it failed in Charpy testing - in the base metal..*sigh*. Further testing of the base metal revealed it is a poor choice for -50F testing (9/10/10 ft lbs at -50). Funny, the MTR shows 65,68,75 at -50F.. As a result we are getting a new test coupon sent to the lab to confirm its properties BEFORE welding... The question is, can I just do a charpy test on the new coupon, to supplement the original test? Or, do I have to do the entire process over to requalify the PQR and subsequent WPS? It has to satisfy ASME and DNV... The original plate is 2.75" thick. If I can do a supplemental, does it have to be a 2.75" thick plate as well or can I use a 2.5" plate?
2. I used SA-516 Grade 70 (P1 Group2) to SA-516 Grade 70 for the coupons. Can I use SA-537 class1, 2.75" thick, instead - which has bettere impact properties? If I can do a supplemental, does it have to be the same material, or just the same P number and Group number?
3. Finally, I used a 2.75" thick coupon because all 3 welding folks I have talked to cannot agree that a 1.5" thick coupon will qualify up to 8". The production weld is 5" thick, using SA516 Grade 70. Impacts are required (15/12).. Can I do it with a 1.5" thick coupon, or am I limited to 2t?
Thanks in advance!





RE: ASME and DNV supplemental charpy test requirement
1. You do not need to re do all of the tests. You may run a supplementary plate and perform charpy tests only. Remember, per ASME the minimum thickness of the test coupon is important. In other words if you run a 1/4" thick test plate and combine the two tests, your qualified range is 1/4" through 8". If you run the test on 5/8" thick or greater your qualified range will be 5/8" through 8". This assumes you don't violate other essential variables ie heat input, and consider certain limitations which pertain to certain processes.
2. P # and Group # are both essential variables for impact tested procedures. You could run a test on P1 Gr 1 to P1 Gr 2 and test both HAZ's & therby qualify both group #'s.
3. I'm assuming you are qualified to 8". Review QW 451 and read al the referenced paragraphs to determine this.