EXAMPLE: GTAW & ASME IX
1) whether new PQR has to be performed if there is change in GROVE TYPE from V to U During production OR only revising the WPS by incorporating the changed GROVE TYPE will be enough.
groove design is a nonessential variable, so issue a new WPS and qualify it with the existing pqr
2) Whether gas purging used during GTAW welding can be consider as BACKING.
the flow rate is a nonessential variable, so you may consider it as backing if you are sure for the composition because the composition is an essential variable for some P numbers (see QW-408.9)
3) Please clarify the meaning of paragraph - QW - 403.5( Only for paragraph below point C) with example.
P no may be the same but group no changes in case where the yield point / ultimate tensile strength changes. Then if impact test is required then the WPS must be re-qualified For non ferrous materials there is no group number so you have to use the UNS no.
4) Please clarify the meaning of paragraph - QW - 202.4b(2)with example.
You have a PQR for welding with GTAW for thickness 14 mm. You have an other PQR for welding with SMAW for thickness 20 mm. Now you have to weld a pipe of 40 mm. You can do the root pass or even you can weld 28 mm with GTAW and complete the weld with SMAW. The issue here is that you can use the GTAW although its PQR does not cover 40 mm
5) whether change of electrode clasification under same SFA e.g. change of electrode from E7018 to E7018-1 or VICE VERSA requires qualification of new PQR.
No, F number is the same but if impact test is required then a new PQR is required because the classification is not the same (classification is a supplementary essential variable)
6) Please clarify the meaning of paragraph - QW - 404.12 & 404.33 with example.
Impact test is a requirement: if you change from E7018 to E7018-1 you need to re-qualify. If the filler metal has the G, then if you change from Oerlikon to Thyssen you need to qualify again. The changes of 404.33 do not require re-qualification but you have to write a new WPS to suite production requirements
Dr. G. Dilintas
I&F Regional Technical Manager
Bureau Veritas Piraeus - Greece
Tel: +30 210 40 63 113/4
Fax: +30 210 40 63 118
Hi, You are correct, Minimum refers to the one cycle for which this part will expose until final work shop PWHT. hence mill test certificate shall include this. Max. SPWHT, refers to additional cycles of heat treatment that are reserved for future repairs during equipment lifetime. Again, these simulated no. Of cycles shall be specified in MTC. The idea is we need to make sure that steel mechanical properties are not compromised upon exposure to multiple repairs (i e 4 cycles in your case). One could say, if steel is subjected to 4 cycles and is ok, then it should by defacto be good for one cycle, yet, this is wrong assumption cause mechanical problems and microstructure of materials varies accordingly based on no. Of cycles for which material will expose. This is apparent in alloy steel and especially for impact test values as an example. In your case, this forged CS with properties before PWHT can be understood to be " as forged" condition (i.e. Wit...
Comments