c276 overlay of cast 625 1

[pwtomlin]

I have a customer who is having using overlaying part of a Alloy 625 casting with ERNiCrMo-4 (C-276) weld wire. I don't have a lot of details but they are seeing "tearing" (cracking?) at the weld-base metal joint. I realize that's a pretty vague description but has anyone encountered a similar problem with C276 weld wire and cast 625 base metal?

 

[metengr]

pwtomlin;
It really sounds to me that these indications are probably lack of fusion (LOF) defects rather than hot tears caused by solification cracking or dilution effects. Assuming not surface defects from casting, both of these materials are very weldable. The problem I have seen is using the GMAW process for weld overlay can result in LOF defects along the fusion zone of the weld region.

 

[stanweld]

Tend to agree with metengr. How is the surface of the casting prepared and what was the welding process used? Both welding process (low heat input/low penertration) and surface contamination can lead to LOF.

 

[EdStainless]

My first hunch would be surface prep. A little oxide residue would prevent good fusion.
The other risk is too low of too high of heat input. with high heat you could generate hot tearing, these alloys have big thermal expansions.

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Plymouth Tube

 

[Duwe6]

Higher Inconels like 625 are infamous for Lack-of-Fusion. The weld parameters have to be 'hot' enough to break down the 625 and cause it to mix with your overlay wire. Careful examination of the weld 'puddle' will show if they are breaking down the 625. If there is not a visible breakdown of the 625 basemetal, all they are achieving is a high-temperature braze.

I'll echo EdStainless, surface prep is critical. Consider a light grinding or heavy wire brushing of the area to be welded. Also consider a 100°C preheat of the 625. Preheat makes things weld better.