Bake Requirement after Chemical Stripping ENP

[Ti_Metallurgist]

Hi all,

Looking for some advice on an issue I am facing. Wasn't able to find an answer here or on Finishing website.

I have some alloy steel parts (46 - 48 HRC) that were electrolessly plated with nickel. A defect downstream forced the supplier to strip the plating. They were instructed to do an embrittlement relief bake after the stripping (before re-plating), but neglected to do so. I am trying to determine if it is okay to use the parts as-is as they claim that they used a non-embrittling solution to strip the parts and did not apply any current.

The TDS for the striping agent is a non-cyanide alkaline solution working at 185F.

Most every resource I've combed through covers the chemical reactions that take place during plating, but I haven't seen any work indicating whether this immersion strip process is potential source of embrittlement. I am looking for anyone with insights into the chemical reactions that take place and whether hydrogen gas may be released to embrittle the steel.

Regards,
Ti_Met

 

[EdStainless]

It isn't the evolution of hydrogen gas; it is the formation of hydrogen ions in the solution.
At that hardness I wouldn't take the risk.
Either remake them, of strip them again and perform a high sensitivity fluorescent penetrant inspection.
They didn't follow instructions, it is their dime.

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P.E. Metallurgy, consulting work welcomed