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Hard chroming process

 

I would like to know if anyone could tell me if it is possible to hard chrome a crankshaft of a rockwell hardness of 55 rc while it is still inside the engine. This is to repair connecting rod journals on locomotive engines.

Thank you for a reply,

Archie Hebert
a diesel service - Thibodaux, Louisiana, U.S.A

Archie,

I would not recommended hard chromium in this case. Yes it is simple to build a tank around a part and plate it. But when you have a hardness on 55 HRC you must shotpeen the crank before hard chromium. If you not there is a possible at the part will show a hard chromium plating with cracks on the surface. Also how will you remove the hydrogen embrittlement? It should be 142 °C for 12 hours after plating when you have a carburized steel.

Regards,

Anders Sundman
4th Generation Surface Engineering
Consultant - Arvika,
Sweden

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In theory, absolutely. Talk to 'brush plating' suppliers like Gold Touch [a finishing.com supporting advertiser] and Sifco. Their customers do this kind of thing all the time. However, you may find that nickel plating is preferable to chrome plating.

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