Issues welding A286 CRES to 430 CRES

[kevlar49]

What are the issues that need to be considered when welding A286 CRES to 430 CRES? We are looking at TIG welding with PWHT to improve ductility of the 430 CRES. Filler likely to be E309.

 

[metengr]

PWHT of 430 stainless steel is not recommended. You either need to either anneal and quench or leave 430 as-welded. 430 stainless steel is a non-hardening grade and requires no PWHT. I would use Inconel versus E309.

 

[metengr]

As a side note to welding A 286, use caution because this material can result in loss of ductility in the heat affected zone. So cooling rate after welding must be controlled to avoid cracking.

 

[TVP]

metengr-- which grade of Inconel do you recommend for this?

kevlar-- What is the HT condition of the A286? A286 is almost always used in the precipitation hardened and aged condition, and welding will most certainly alter this condition. Are you sure that this is technically feasible, meaning stresses in the weld joint?

 

[EdStainless]

His 430 may be martensitic, it depends on the C level.
What is the heat treat condition of the 430 and the C?
What is the heat treat condition of the A286?

For a good weld you really need both of them annealed, but then you don't have strength in your A286.

Using a Ni based filler will get you closer in thermal expansion, 309 is asking for trouble with these alloys.
There are a number of fillers that would work. NiCrFe-6 is common.

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Plymouth Tube

 

[metengr]

Optimum welding for A 286 is in the solution treated condition only. Filler metal would be Inconel 182.