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Laser engraving of chrome plating

Q. I'm in the process of manufacturing a bone chisel for medical purposes. The material is going to be stainless steel type 420A and the finish will be glass shotpeen at 30 psi. I want to coat the piece to make it more corrosion resistant. I know I could use passivation process (astmb633.htmla380.html" --> & ASTM A967 ) but I already had problems of rust around laser engraving. We have solved the problem but the doubt is still reminiscent. I can do it by chromium coating, which I have no standard for. Can I laser engrave chrome coating without destroying the oxide layer? Should I chrome before, then laser engrave and passivate over? So many questions ...

Thanks,

Marc Tebo
- Canada
2003

A. If you laser etch you must passivate afterward. Proper passivation of the item will help very much, but 420 is not the greatest grade of "stainless" steel, as you know. The only way to prevent corrosion in the etched area is to passivate afterward, unless you coat the etching also. You need to talk to a good plater who knows how to chrome plate stainless.

Lee Kremer
Stellar Solutions, Inc.

McHenry, Illinois

2003

A. Advantage of 420 SS is hardness, but it lacks corrosion resistance of alloys such as 310 or 316. Best thing you can do is to engrave it then plate it. Chrome is good but generally not considered as corrosion resistant as other plates like electroless nickel. I would chose EN instead of chrome. About passivation you must not do it if you are to plate afterwards (it has to be activated again to adhere the subsequent plate) G. Marrufo-Mexico

Guillermo Marrufo
Monterrey, NL, Mexico
2003

How to blacken engraving on Stainless Steel without harming the Chrome Plating

Q. Hello,

I have 1000's of stainless steel jewelry pendants which are chrome plated. I have laser engraved text on the pendants. The text is now black, but not quite dark enough.

My question: How do I make the black darker without damaging the chrome finish?

Thanks, Glen

Glen Jonees
- St Peters, PEI, Canada
April 3, 2015

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