43089

Threshold for Hexavalent cross contamination on Trivalent parts [Kentucky] 

November 20, 2006

I recently received a test report for a trivalent part that included a "chemical content evaluation" which shows the part had 10 ppm Hexavalent Chromium. Does anyone know if there is a threshold level for an acceptable amount of hex chrome on a "Hex free" part? My thought is this is most likely carry over where both hex and tri are ran on the same line, but if I submit this to an automotive customer is it acceptable? I have ask several people in the industry, and no one has been able to say for sure. 10 ppm is not much, but if hex free means 100% free of hex chrome, I do not think it would be acceptable, unless the margin of error for the test is more than the total ppm. Any information that can be supplied will be appreciated.
Thanks,

Kevin Davis
Automotive hose and tube mfg. - Versailles, KY, USA

You are right, 100% free means 100% of Hex.
Most of the platers still have tri and hex conversion coat process running of the same line.

Find someone who has trivalent on different line or who just does not do any hex...

Hemant
- Lakeland, FL

This is not acceptable in the automotive customer's eye. The EU ELV and RoHS guidelines have recently removed the wording for intentional vs. unintentional, yet many of the auto guys have not changed their environmental specifications. Therefore, your question to yourself needs to be if you are using it intentionally or unintentionally. That is a problem. If there are technical alternatives (especially if it cost is lower) that you are not using, then that may be considered intentional. If you are using same lines for both hex and tri chromate conversion coating and do not have a proper method for removing residue, that may be considered intentional. Hope this helps.

Jeremy Lynn
- Newnan, GA USA