Preheat for dissimilar joint

By maringan_htgl Date 06-27-2012 10:24

Dear all,

my client want to run a PQR for the material 2-25 Cr -1.0Mo to Inconel 601 using welding process GTAW and SMAW .
my query is, prior to commencement welding does it need a preheat ?
The actual thickness of 2.25 Cr material for production is 250 mm to be welded to Inconel pipe with partial penetration.

Any advice would be appreciated.
thank you

By OBEWAN

Date 06-27-2012 11:26

What does your welding engineer say? If you do not have a welding engineer you could get in deep trouble real fast.

By js55

Date 06-27-2012 12:06

Virtually every code I know of states that the most stringent preheat applies in any dissimilar application.

By Len Andersen (***)

Date 06-27-2012 13:01

Ladies and Gentlemen,
I suggest contacting the www.aws.org engineers at (305) 443-5951 Fax or with an e-mail, the consumable manufacturer i.e. Lincoln, the Inconel manufacturer and be careful. If it was my "situation" I would have delayed cracking concerns and fatigue life concerns. I hope this helpful.
Sincerely
Len Andersen weld@spemail.org
914-536-7101 , 212-839-6599 8-4 New York Time , 914-237-7689 (H) www.lenandersen.com

By maringan_htgl Date 06-27-2012 14:03

Dear all,

Thanks a lot for the replies.

I've just got the following advice from my application technologist:
"the material 2.25Cr-1.0Mo requires preheating of 200-280°C and eventually PWHT while the Inconel 601 requires neither preheating nor PWHT. The recommendation will be to preheat and buffer the 2.25Cr-1.0Mo with ENiCrFe-3 (2 or 3 layers) – then PWHT. The joint can then be completed with the same consumable (No preheat or PWHT required)."

I feel that this answer has already helps