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Plating a metal stamping with hardened stud attached

I am trying to get an assembly plated without having to bake to prevent hydrogen embrittlement. The base part is hot rolled p&0 steel and the stud is AISI 15B21 steel. The stud will be heat treated to Rc 22-30 prior to staking into the metal plate. Is there a method of zinc plating for this that I will not have to worry about hydrogen embrittlemnet? This will be a high volume job.

Robert Lee
metal stamping shop - Clinton, North Carolina
July 21, 2008

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July 22, 2008

Hi, Robert. My understanding is that hydrogen embrittlement relief is not required for parts of hardness below about Rc38. But this is a high volume job and you should get a second and third opinion. Good luck.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

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Ted is quite correct. I would suggest that you would want to minimize embrittlement. To assist in this goal you should discuss with the plater the manner in which the part will be pickled and plated.

I would suggest an acid zinc electrolyte (high efficiency yields lower gas evolution equals lower embrittlement). Also, with the heat treatment, the plater will probably have to aggressively pickel the scale. Again to reduce gas evolution (since the absorption of this hydrogen gas is what leads to embrittlement) the plater should be using an acid additive which will inhibit attack on the basis metal, and accelerate the pickel process.

Gene Packman
process supplier - Great Neck, New York
July 24, 2008