Is ASTM B633 Zinc Electroplating RoHS Compliant?

A. Hi, Alex.

The answer is neither yes nor no. In the old days the answer was "no" because virtually all chromating used hexavalent chrome. Today most chromating uses trivalent chromates, so the answer CAN be yes, probably usually is yes, but it isn't necessarily. I think, for now, you need to specify RoHS compliant in addition to ASTM B633.

Regards,

A. Hi, Ellen. It can be very tricky to say that a spec has been "superseded" by another spec. The actual wording of the cancelation notice is: "Federal Specification QQ-Z-325C, dated August 18, 1976, is hereby canceled. An existing commercial standard which covers this material is American Society for Testing and Materials Standard B633."

That is, it doesn't say "equivalent" or "superseded"; it doesn't even assert that ASTM B633 is the best alternative spec. -- it's just "a" spec covering zinc plating.

It matters because: suppose the old spec had testing requirements of some sort and the new doesn't ... have those testing requirements gone away or do they endure? (That was a rhetorical question -- I don't think there is a right answer). The designer must insure that the needs of the application will be met, and has no choice but to obtain the new spec and spell out exactly what s/he needs.

"Type 1" is no chromate or post-treatment, so RoHS compliance should be easy. I think ASTM B633 -11 now addresses RoHS compliance, but there are many older editions of ASTM B633, so it might be safest to spec "per ASTM B633- 11 ... and RoHS compliant". It would not surprise me if RoHS compliance becomes a moving target as time goes by.

Regards,

A. Hi Patrick.

Type 1 is "no chromate", so I'd expect it to be RoHS compliant, but your supplier should not be trusted to be doing ASTM B633 if they don't have a copy of it on hand. It's possible that your supplier actually doesn't know, but it's at equally possible that he doesn't want to be on the hook for guaranteeing compliance, or that he knows his present chemistry isn't RoHS compliant :-(

ASTM B633 -11 now addresses RoHS compliance.

Good luck.

Regards,

Q. Ted, thank you for the reply. I do have a copy of ASTM B633 -11 and it only mentions RoHS once and that specifically is in the scope, paragraph 1.6. "This standard has been revised to address RoHS requirements that seek to limit the exposure of workers and the public from exposure to toxic metals. Additional types have been added to permit non-chromate passivate treatments to be used in replacement of hexavalent chromium." Copyright ASTM International...

The only types added from the 1998 revision have been Types V and VI. So I still don't know if Type I is RoHS compliant or not. Seems like there should be a way to force this by type without adding additional verbiage to purchase orders.

A. Hi again, Pat. I don't have a copy here, but I'll bet you find that the two new types, V and VI, are the non-hexavalent ones.

Plating-wise, RoHS is chiefly concerned with cadmium, lead, mercury, and hexavalent chromium. Type 1 zinc plating has no chromate so I'd expect it to be RoHS compliant.

I understand your wish to avoid verbiage, but I don't consider "and RoHS compliant" to be a burdensome amount of verbiage, and I think the risk of leaving it out on a plating P.O. isn't worth it. Milt Stevenson is an ASTM B633 committee person and plating shop manager who urges the same thing in letter 37583.

90% of plating contract disputes seem to be about whether unspecified things are "implied" or not :-)

Regards,

A. Hi Zakaria. I believe that you will find that types 5 and 6 are the types which are intended to be hexavalent-free and therefore RoHS compliant. But don't attempt to incorporate ASTM B633 into your drawings or purchase orders unless you are looking at a copy of it; and don't even dream of claiming you are complying with it except after reviewing it beginning to end.

My personal position, with no claim to being right, is that the words "RoHS compliant coatings" should specifically and explicitly appear on every drawing, specification and P.O. where RoHS compliance is required.

Regards,

A. Hi Allan. May we assume you are asking about ASTM B633? -- there could be other specs which use the same term with a different meaning so it's safest to reference a particular spec when you ask what terminology like "Type 2" means; This plating is probably not RoHS-compliant since it probably employs hexavalent chromating.

Regards,

A. Hi Leo. RoHS is a requirement of the European Union for certain types of parts. If these fasteners are not going to Europe, and if nobody further down the line is requiring or claiming RoHS compliance, then it's not a requirement which you should impose on yourself at an inconvenient juncture.

However, I would not take it upon myself to claim RoHS compliance based only on the fact that trivalent chromates were used. Some very old chromates had (if I recall correctly) small amounts of lead as an accelerant. Or there might be some other forbidden substance somewhere; and RoHS is a moving target. Don't take it upon yourself to certify that your suppliers' parts are RoHS compliant if they won't.

Regards,

A. If you do at some point need to prove RoHS compliance, you will need to do destructive testing of the actual PARTS; a laboratory will need to physically remove the coating layer, mechanically or with chemical digestion, and analyze this layer for substances of interest. It is a royal PITA, and not cheap (I speak from experience), so if you don't absolutely HAVE to certify to RoHS...