Where the
world gathers for metal finishing
Q&As since 1989


-----

RoHS allowable Hex Chromium levels in galvanized steel

2005

I work for a manufacturer of appliances that uses galvanized chemically treated dry coils.

There is some confusion by our Coil Suppliers relating to the RoHS directives in the following two areas:

1. The Maximum Concentration Values of Hex Chromium acceptable in the RoHS directive e.g., some are relating that 1000 PPM are acceptable and some are saying Hex Chromium is prohibited, (zero) acceptable, therefore need a new passivation process is needed. Which is it?

2. The Maximum Concentration Values for Hex Chromium test, is it on the coating itself separate from the substrate or is it on the substrate material with coating? Hex Chromium is difficult to separate from the steel.

Greg Terek
Manufacturing - Kearneysville, West Virginia, USA

---

2005

The answer to your second question is that it's just the coating; you can't include the weight of the substrate. Your questions were answered already in previous threads if you want to spend protracted time with our search engine. But in the end it comes down to this, Greg: we can't use hexavalent chromate conversion coatings anywhere in the long term or most places even in the mid term; a new passivation process is needed -- either trivalent chrome or chrome-free. As it was put by others on similar threads: "You can change at a time convenient for yourself or at a time inconvenient for yourself".

I say change now and you won't have to worry about what components are covered by RoHS, what components are covered by ELV, what components are covered by automotive specs, and the exact amount of hexavalent chromium permitted by all the various regulations, codes, and specifications. It wouldn't surprise me if the next round isn't local codes, like no hex chrome parts in Orange County or Carbon County. Change now :-)

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey