P91 preheat to 899F.
P91 preheat to 899F.
(OP)
We have a customer that has come back on our ASME P91 GTAW procedures that 400deg preheat is insufficient. They require us to maintain a MINIMUM preheat of 899F!!! No, that's not a typo.
Here's the real kicker....they ALSO require a MAX heat input of 1.2 kJ/mm.
Yes, I know it's impractical but they are adamant that we meet their requirements.
I am curious of the community's collective thought. We are a bit curious here and treating it like a brain-teaser...what would happen if we ACTUALLY tried to weld it with those req.
Here's the real kicker....they ALSO require a MAX heat input of 1.2 kJ/mm.
Yes, I know it's impractical but they are adamant that we meet their requirements.
I am curious of the community's collective thought. We are a bit curious here and treating it like a brain-teaser...what would happen if we ACTUALLY tried to weld it with those req.





RE: P91 preheat to 899F.
Or maybe they need a consultant's help in understanding the need for preheat.
Best regards - Al
RE: P91 preheat to 899F.
RE: P91 preheat to 899F.
RE: P91 preheat to 899F.
RE: P91 preheat to 899F.
Forget about C or F. The client is totally at loss and has ill-knowledge about grade 91 steel.
Some education from the vendors end might help to speed up the work without undue interference and hindrance.
Ask them to refer any EPRI Grade-91 document or API-TR-938B as a good educative document on grade 91 steel.
That's my advice.
Thanks
Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
Ontario,Canada.
ca.linkedin.com/pub/pradip-goswami/5/985/299
RE: P91 preheat to 899F.
A Perspective on the Selection of Preheat, Interpass, and Post-Weld Cool Temperatures Using Grade 91 Steel as an Example
"Everyone is entitled to their own opinions, but they are not entitled to their own facts."