Inconel overlay on duplex/super duplex SS

[Ramyesh]

Hi All!

Is it common practice to have Inconel 625 overlay/inlays on super duplex stainless steel? We commonly overlay Inconel 625 on carbon steel.
Never come across such a situation before. Wondering if it is done at all?

Thanks in advance,

Regards

 

[cap1a79]

No. it is not normal practice at all.
Generally, when weld overlay is applied, the base metal will be CS/LTCS/low alloy steel (<--the case of low alloy is kind of specific.)
Unless the minimum design temperature is below -46 C or maximum design temperature is more than 454C, the base metal will fall under the group of the three materials.



Lee SiHyoung,
WorleyParsons Oman Engineering,

 

That is indeed not usual. May I guess that it is done for erosion corrosion resistance due to local flow conditions in small areas?
.
Normal joining of superduplex SS is already fraught with fabrication issues affecting corrosion resistance, so I'm not sure how you would qualify this to meet the same test requirements, which are undoubtedly spelled out in the tech spec. The vulnerable region will be the exposed SDSS HAZ at the edge of the I625 overlay.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[Ramyesh]

Thanks to both Cap1a79 and Ironic Metallurgist for the speedy response.
I do not have all the details on the job yet, other than the oil field is in a highly corrosive environment and high-pressure application, where CS or LACS cannot be used even with Inconel overlay, I'm told. I've requested for more job specifics.
Regards

 

[EdStainless]

Given the issues with welding on SDSS you would be better off making this out of solid 625.
We needed to overlay some SDSS because of erosion issues, we went with HVOP so that we could keep the SDSS under 400F.

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P.E. Metallurgy, Plymouth Tube

 

[Ramyesh]

Thanks, EdStainless. Appreciate the input.
Regards