PWHT Mutiple Times on Chrome P11 and P22
PWHT Mutiple Times on Chrome P11 and P22
(OP)
The vendor is fabricating P11 and P22 piping. Spools are placed in an oven for PWHT so the whole part. Afterwards they installed weld-in type thermowells so a second local PWHT was done. Now I find the welds on the thermowells in this B-31.3 piping were installed as a fillet welds and not full pen. They are going to cut these out and reweld and for the 3rd time PWHT these spools.
I'm concerned about the metallurgy being worked so many times.
These are DMW's as the thermowells are 316ss and the pipe 1.25cr and 2.25cr. Any thoughts on the issues this reworking might create? Thanks
I'm concerned about the metallurgy being worked so many times.
These are DMW's as the thermowells are 316ss and the pipe 1.25cr and 2.25cr. Any thoughts on the issues this reworking might create? Thanks





RE: PWHT Mutiple Times on Chrome P11 and P22
Thanks,
Mike
RE: PWHT Mutiple Times on Chrome P11 and P22
RE: PWHT Mutiple Times on Chrome P11 and P22
Regards,
Mike
RE: PWHT Mutiple Times on Chrome P11 and P22
If you are concerned regarding notch toughness and strength properties at ambient service temperature because of a specific application, you can have a welded coupon run to simulate the aggregate PWHT time at temperature and compare with one PWHT application, and evaluate the base metal heat affected zone (hardness and notch toughness). This is easy enough to do and would address your concerns.
RE: PWHT Mutiple Times on Chrome P11 and P22
Regards
Alan
RE: PWHT Mutiple Times on Chrome P11 and P22
I just want to be sure footed and not create a worse problem by over working the metal.
BTW We are at a crossroads with these thermowells and need to decide to either continue with the weld-in type or switch to flanged type we have had some cracks in the welds in the Hydrogen service (some after welding and some a month after placed in service)
RE: PWHT Mutiple Times on Chrome P11 and P22
RE: PWHT Mutiple Times on Chrome P11 and P22
Based on your recent response, I do not see an issue with using socket welded thermowelds. I would recommend using Inconel filler metal only if you are welding a dissimilar material (stainless steel thermoweld to the pipe).
RE: PWHT Mutiple Times on Chrome P11 and P22
RE: PWHT Mutiple Times on Chrome P11 and P22