The authoritative public forum
  for Metal Finishing since 1989
-----

Hexavalent-free passivating on steel rolls

Regarding hexavalent-free passivating processes on electrogalvanized steel, I need to know if there are North American steel shops that do this. My current understanding is that hex-free processes only are possible on a small scale, so I would have to post-plate my stamped parts. The cost of this choice (post-plating) would double the piece price. What is the state of the art on hexavalent-free passivating on large quantities of steel stock (prior to stamping/processing)?

Michael Zick
- Farmington Hills, Michigan USA

I'm not sure I understand you, are you looking to plate the roll before the stamping process? What about the edges after stamping process? The corrosion req's are difficult to meet with plating after stamping. I would think that it would impossible to pass when you pre-plate the stock.

Brian Lucas
- Wolcott, Connecticut

----
Ed. note, Nov. 2010: this inquiry was from the year 2000 and the situation has changed dramatically, with trivalent chromating being nearly de facto today, and no longer applicable only to small pieces or at a high premium. Preplate does leave the edges unplated as Brian notes, but due to the sacrificial protection offered by the zinc plating, exposed edges are not always a problem.