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When to heat treat

Much has been said about hydrogen embrittlement of steel. My question is at what point in the plating process is the baking of the metal done? We have restraint parts(seat belt buckles) that will be plated with copper, nickel,t hen gold.

Thanks for your help.

Anthony Lord
- Little Rock, Arkansas
2002

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Baking in-between coatings isn't advisable from a practical/quality standpoint and from a cost standpoint. Stopping for an intermittent bake will only oxidize the surface necessitating etching and reactivation which will not only dull down the appearance, but make adhesion much tougher.

What nearly everyone does is plate all 3 deposits and then get the parts right into the oven for baking.

Milt Stevenson, Jr.
Syracuse, New York
2002

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To expand on Milt's answer, many parts that are Rockwell C hardness of 36 and greater are baked before plating as well as after. The bake before relieves residual stresses that might cause cracking during the plating process. If the steel can take it without detriment, 375F for an hour is common.

Good luck!

Lee Gearhart
metallurgist - E. Aurora, New York
2002