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Laser marking of passivated parts

When parts are passivated, can they be Laser Marked after passivation?

Pat McKinney
Engineer - Glenolden, PA, U.S.A.
2004

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First of two simultaneous responses --

Pat, my company allows it, and we do it on our parts every day. I can't think of a reason I wouldn't allow it.

Lee Gearhart
metallurgist - E. Aurora, New York
2004

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Second of two simultaneous responses --

Laser marking of passivated stainless is done all the time in the medical industry BUT keep in mind that following laser marking, the parts go through a secondary passivation! The laser marking somehow impacts the passive layer and without the secondary passivation, the parts rust in the region around the marking.

Milt Stevenson, Jr.
Syracuse, New York
2004

I do not like most laser mark! Sure it is a nice way to ID a part, but the brown layer is an iron rich layer. I dare say that if you SEM just the laser oxide it would not read like SS. I do like a laser mark that is very deep and with proper means removing the oxide layer and then relying on the depth of laser for contrast. I have run lots of parts through out humidity cabinet. Laser marking fails and the darker the marking the worse it fails.

Jon Quirt
- Minneapolis, Minnesota
2004