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Masking for Carburization

I am processing machined component (4120 Steel) which requires two different hardness zones along the length. The part will need to be carburized, and the lower hardness zone will require some sort of masking prior to carburization. Can anyone recommend an industry accepted, cost effective process for achieving this? The annual volume for this part is quite high (1,000,000 + per year).

I am really looking for a cheap, consistent copper plating process to mask off a certain portion of the part prior to heat treat. Thank you.

David Martinson
automotive parts manufacturer - Michigan
2005

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2005

Either cyanide copper strike followed by acid copper plate to .0005", or cyanide copper for the full thickness. The most costly part of this may be the masking, but with no idea what the part looks like, it's not possible to make suggestions. You might be able to use partial immersion, and it could possibly be better to copper plate all over and then selectively strip the area you want to carburize.

Jeffrey Holmes, CEF
Spartanburg, South Carolina

You didn't explain anything about the shape, size or plated areas of your parts but you may also want to look into selective (brush) copper plating. It is basically intended for plating simple geometries selectively and there are chemistries for plating onto alloy steel. The equipment is rather inexpensive, portable and can also be automated for high volumes.

Guillermo Marrufo
Monterrey, NL, Mexico
2005

best way would be to copper plate there are some no-carb paints but this is labor intense unless they could be dipped.

Kevin Stone
steel treating - Saginaw Michigan
April 22, 2009