scale removal after case hardening

wax on, wax off

Ultrasonic chisel

Pickling?

When I was running zinc and cad plating lines, we always used an "acid dip, rinse, caustic/soap dip, rinse" procedure before plating. It usually worked. If not, we acid dipped again.

Here at our shop we wrap the parts in a stainless steel foil and close the ends tight to limit air exposure which causes most of the scale. This should minimize your problem. Good luck.

If you are hardening in an oven, try to find one that uses an inert atmosphere such as nitrogen. This works well in heat treating and keeps scale to a minimum. As for scale removal I use to use a product called Brightdip. Its a combibation of acids that works very well, just dont leave in to long.

Foil and inert atmospheres tend to interfere with case hardening, which needs a carburizing atmosphere. The scale forms when the part is quenched, and consists mainly of iron oxides and burned oil residue. The acid/caustic combination I mentioned above will usually remove both.

Vibration finish. Vibrating Converyor filled with stones and parts move along in it.

Please refer to the link given below.

http://en.wikipedia.org/wiki/Electroless_nickel_plating

We do shot blasting after Carburising and hardening. That removes the scale but you will probably need to do more cleaning as specidfied earlier for electroless Nickel plating for proper electrical conductivity.