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Need to post bake case harden parts after electroplate?

I'VE BEEN TOLD THAT THERE IS NO NEED TO BAKE CASE HARDEN PARTS AFTER ELECTROPLATING BECAUSE OF THE HARDNESS. IS THIS CORRECT OR IS THERE A STANDARD FOR BAKING CASE HARDENED PARTS?

BOB BAUER
plater - MPLS, Minnesota
October 1, 2010

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Bob,

Is this nitride case hardening or carburising?

If it is carburised the subsequent heat treatment is normally carried out at 135 C (275 F) for about 6 hours.

If it is nitrided and you have plated over the nitriding then the material is normally treated as an ultra high strength steel, heat treatment is then carried out at 195 C (375 F) for 23-24 hours, dependent on whose specification you read.

If you are not plating on the nitrided surfaces specifications vary. Some require that you heat treat regardless of where you have plated, again treating it as an ultra-high strength steel, others allow heat treatment based on the strength of the non-nitrided steel.

I would personally work on the basis of heat treating for ultra-high strength steel, regardless of where the plating is carried out. This way you know you will be safe.

Brian Terry
Aerospace - Yeovil, Somerset, UK
October 4, 2010