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COLORING OF STAINLESS STEEL PARTS?

DOES ANYBODY HAVE INFO ON THE COLORING OF STAINLESS STEEL PARTS. WE ARE PRODUCING VARIOUS SIZE SCREWS IN STAINLESS STEEL FOR USE IN SURGICAL PROCEDURES AND WANT TO USE DIFFERENT COLORS TO IDENTIFY DIFFERENT SIZES. THE COLORING CAN NOT BE A "PLATING". I BELIEVE A PROCESS, SOMETHING TO DO WITH "CHROMIC ACID ELECTROLYTIC" ACTION IS AVAILABLE. CAN ANYBODY HELP WITH THIS?

REGARDS,

BOB LYE
- SYDNEY, NSW, AUSTRALIA
2003

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Bob,

I know that there is a process patented by Inco that is expired. Also I'm aware of a company in the states that does it but do not remember who. The colors are limited by a light interference process. We color code a lot of titanium parts. I have thought about the coloring process for stainless steel as I could make a great market here in the states with it but I feel that the hex chrome is an issue. Some is bound to be trapped in the film (even if the majority is trichrome from a redox/reaction). This is a no no for implants. Respond if you have ideas around this and I will contact you off line.

Jon Quirt
- Minneapolis, Minnesota
2003