A487 CA6NM to 9Cr PWHT temp?
A487 CA6NM to 9Cr PWHT temp?
(OP)
Hi, I would like to know what would be the best PWHT temperature for a weld of A487 CA6NM with a 9Cr carbon steel.
I understand that the PWHT temp for the CA6NM is about 1150F and for the 9Cr is about 1350F
Thanks for your help
R
I understand that the PWHT temp for the CA6NM is about 1150F and for the 9Cr is about 1350F
Thanks for your help
R





RE: A487 CA6NM to 9Cr PWHT temp?
RE: A487 CA6NM to 9Cr PWHT temp?
we are going to weld a nozzle (9cr-1Mo)to a pump case (CA6NM) running at a temperarture of about 700F. No welding procedure qualification is required.
Thanks
RE: A487 CA6NM to 9Cr PWHT temp?
What I would do is to butter the entire weld prep end of the 9Cr-1Mo nozzle and perform a separate PWHT before you weld it to the CA-6NM pump casing. Use preheat for buttering to the 9Cr-1Mo base material. The butter layer should be 1/4" thick to assure that welding the nozzle to the pump case will not affect the Cr-Mo base material. The filler metal should be 410NiMo for buttering. This is a low carbon martensitic stainless steel filler metal that would be compatible with Cr-Mo and CA-6NM.
After you buttered the nozzle, weld it to the CA-6NM pump casing using the same filler metal with no preheat. Once this operation is completed, perform a local post weld heat treatment of the nozzle attachment weld at 1150 deg F for 1 hr/inch of weld deposit thickness (not base metal thickness of the pump case).
I would still insist on qualifying a weld procedure before you perform this work. I would also perform a wet fluorescent MT after the nozzle is welded to the pump case.