Alloys 52 or 82/182

By jon20013 (*****)

Date 03-23-2007 12:31

Dear forum members, I am trying to gather all of the information I can from this brain trust about use of the above materials for making full penetration welds in very thick sections and in highly restrained conditions. The materials to be joined are SB166 / 690 through SA516, Gr. 70. As of this writing, the plan is to make the entire through thickness of the joint with either ERNiCrFe-7 or ERNiCrFe-7A and I'm concerned over this alloys tendency to crack...

By MBSims

Date 03-23-2007 22:08

Jon,

I have seen 82/182 used in groove welds up to 2" thick in reactor vessels joining Inco 600 to SA-533. In that case a 82 weld inlay or butter was used on the LAS side, then the groove weld made using SAW. What do you call "very thick"?

By jon20013 (*****)

Date 03-24-2007 09:19

4 inches on the carbon side, with SB166/690 nozzle through wall.

By jon20013 (*****)

Date 03-26-2007 14:51

Just bumping this back into the living world, would love getting some more input!

By js55

Date 03-26-2007 15:38

I notice that ERNiCrFe-7 has 5%max Mn. Mn was one of the elements added to NiCrFe-3 (182) to improve all posiiton crack resistance over the old NiCrFe-1(132).
It also appears as though one of the primary alloying elements is Nb. Which means that it should respond under welding regimes similar to 625 (although 7 has less than the Mo-3). Just looking at it what is working against you for hot cracking is Al, Cu, and Nb. Mn may be working for you.
I sure would love to get my hands on some really good metallurgical info on this alloy (i wonder if Dick has anything specific on this alloy).
The A version specs out Co, Zr, and B. While reducing the Cu content and the Mn considerably. Would this be hot crack adjustments? The Al has been increased.
I know I'm describing the water here, but it may raise pertinent questions.