Section IX, B31.3, and impact tested WPS
Section IX, B31.3, and impact tested WPS
(OP)
I need to qualify a welding procedure in accordance with Section IX, with the supplementary essential variables for Charpy impact testing as required by ASME B31.3.
The base material is 304 SS, with production material thickness ranging from 0.500" to 1.000" in thickness. This is for cryogenic service and impact testing of the weld and HAZ will be performed at -320 F. I intend to use a GTAW and SAW process combination on a 1/2" thick test coupon for procedure qualification.
I have the following problems:
1) Per QW-403.6 and QW-451 of Section IX, the qualified thickness range using a 1/2" plate will be 0.500" to 1.000". However, per Table 323.3.1 of ASME B31.3 (falling under column A for "Requiring Impact Tests Only on Welds") the qualified thickness would be 0.250" to 0.750". It seems that in order to meet both codes, 2 procedure qualifications would have to be performed. (And, it seems for someone requiring even more range qualified, the amount of PQR's would continually grow because of the way the two codes overlap in qualified thickness)
2) I recently attended a Section IX course where the instructor stated that impact tests for multiple processes should include a sample from each process. At the time I took this to mean that one set of charpies should be taken from one process, and another set of charpies should be taken from the other process, etc. Or, it now occurs to me that I suppose it could be taken that a single set of charpies should include both processes in the same specimen. The fault I see with the second interpretation is that if there were 3 processes it would not be possible to include all of the processes in one specimen. The problem I have with taking 2 sets of charpies, one set from each process, is that I am told by the lab performing the testing that even if I split the two processes evenly across the 1/2" test plate, they would have difficulty in machining a full size set from each process (given the amount of material).
Please contribute any thoughts concerning these two issues, point out any oversights, alternate ideas, or proposals on the best way to qualify the WPS. Thanks.
The base material is 304 SS, with production material thickness ranging from 0.500" to 1.000" in thickness. This is for cryogenic service and impact testing of the weld and HAZ will be performed at -320 F. I intend to use a GTAW and SAW process combination on a 1/2" thick test coupon for procedure qualification.
I have the following problems:
1) Per QW-403.6 and QW-451 of Section IX, the qualified thickness range using a 1/2" plate will be 0.500" to 1.000". However, per Table 323.3.1 of ASME B31.3 (falling under column A for "Requiring Impact Tests Only on Welds") the qualified thickness would be 0.250" to 0.750". It seems that in order to meet both codes, 2 procedure qualifications would have to be performed. (And, it seems for someone requiring even more range qualified, the amount of PQR's would continually grow because of the way the two codes overlap in qualified thickness)
2) I recently attended a Section IX course where the instructor stated that impact tests for multiple processes should include a sample from each process. At the time I took this to mean that one set of charpies should be taken from one process, and another set of charpies should be taken from the other process, etc. Or, it now occurs to me that I suppose it could be taken that a single set of charpies should include both processes in the same specimen. The fault I see with the second interpretation is that if there were 3 processes it would not be possible to include all of the processes in one specimen. The problem I have with taking 2 sets of charpies, one set from each process, is that I am told by the lab performing the testing that even if I split the two processes evenly across the 1/2" test plate, they would have difficulty in machining a full size set from each process (given the amount of material).
Please contribute any thoughts concerning these two issues, point out any oversights, alternate ideas, or proposals on the best way to qualify the WPS. Thanks.





RE: Section IX, B31.3, and impact tested WPS
RE: Section IX, B31.3, and impact tested WPS
I've reviewed B31.3 and concur that the impact test requirements in B31.3 and ASME Sec IX do not match. Obviously you want to qualify your WPS per B31.3 to avoid the need for production impacts and unfortunately it appears to me that in your case, more than one test will be necessary if you want your WPS to meet both Codes, for the range of 1/2" - 1". On the other hand if you don't need to qualify impacts to Sec IX, why not run one plate on 3/4" thick material.
RE: Section IX, B31.3, and impact tested WPS
Then create a WPS within the rules of Sex IX only. If you then need the Sec IX WPS to have a lower min T then do another coupon with the same parameters on 1/4" material and do impacts only. Then combine both PQR's for one WPS. Thet will not eliminate the fact that the codes do not match but will get your min T down for Sec IX only.
Or just add a note on the WPS that indicates one MIN T for B31.3 work and another for any other codes of construction.
Here are some interpretations that may be helpful or informative.
B31-85-031 Thickness Range for 31.3
IX-04-04 Combining PQRS
Gerald Austin
Iuka, Mississippi
http://www.weldingdata.com
RE: Section IX, B31.3, and impact tested WPS
Just a bit confused as to why you need to have the lower ASME IX thickness.
ASME IX states the impact tests shall be made when required by other sections.
Therefore if B31.3 gives a range of T/2 to T + 1/4" that is what you will work to when fabricating B31.3 pipework.
Is there anything wrong with having the three base metal ranges listed on the one WPS or as an attachment?
(1) Base metal thickness range without impacts ASME IX
(2) Base metal thickness range with impacts ASME IX
(3) Base metal thickness range with impacts B31.3
Regards,
BB