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Ted Mooney, P.E. RET

The authoritative public forum
for Metal Finishing 1989-2025

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Black oxide coating won't take
I recently had some 8620 low alloy steel castings black oxided, unfortunately we had to do some rework on the castings and the black finish was removed. We sent the castings back to be black oxided, which did not work. The castings would not form the black oxide on the surface. Can this process only be preformed once? I'm assuming we are forming Fe3O4.
Thanks in advance.
- Myerstown, Pennsylvania, USA
2003
One of the two most popular suppliers of Black Oxiding products used to use their "Stainless Steel Black(ing" product for plain cast iron.

Robert H Probert
Robert H Probert Technical Services

Garner, North Carolina

2003
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