Summary for qq-z-325 vs astm b633 Discussion
QQ-Z-325 vs. ASTM B633 is discussed as a standards question about whether the two are interchangeable. Mauricio Guerrero asks if they can be used the same way. Milt Stevenson, Jr. explains that when a military specification is canceled and replaced, the equivalence is one-way: if a job calls for the canceled Mil spec, you can automatically move to the ASTM spec named in the cancellation notice. But the reverse is not guaranteed; if the work is specified to ASTM B633, you should not assume you can simply fall back to the old Mil spec, especially after a long time has passed. He notes that the old procedures may still be present in the ASTM document, but they should not be relied on without checking. The thread closes with Dave Gresham thanking Brian and noting that the standards are confusing.
Q. Are these two standards interchangeable?
Mauricio Guerrero
Product designer – Lake Forest, California
January 14, 2010
A. FED QQ-Z-325
[⇦ this spec on DLA] was canceled in 1978; how could it be equivalent to ASTM B633 which has been continually revised and upgraded over the 30+ years since QQ-Z-325 became canceled and thus NON-CURRENT. For instance, ASTM B633 makes provisions for non-hexavalent conversion coatings (i.e. RoHS compliant). Anyway, just because some “virtual” expert on finishing.com says 2 specs are equivalent, are you really going to bank on that advice and apply that to some design or parts to be plated? That’s dangerous and the only person that should be answering this question is the design authority ultimately responsible for the safety and liability of the item to be plated.
Milt Stevenson, Jr.
Plating shop technical manager – Syracuse, New York
January 22, 2010
A. Mil specs replaced by ASTM specs have a one-way equivalence. If you are told to do the job according to the canceled Mil spec, you automatically bounce to the ASTM spec (or other industry spec) mentioned in the cancellation notice. However if you are told to use the ASTM spec it’s not necessarily true that you can ignore it and go off the old Mil spec. Especially if, as Milt mentioned, it’s been a long time since the cancellation. The procedures from the Mil spec are probably still present in the ASTM spec, but you should not count on that.
Ray Kremer
Stellar Solutions, Inc.
McHenry, Illinois
February 9, 2010
Q. We are about to re-source an old component of ours designed originally by my colleagues in the U.S. back in the early 1990’s and they have specified a finish of “Zinc plate per QQ-Z-325 Class 3 Type I or II”. I gather this has now been cancelled but does anybody know what the UK “equivalent” would be to the standard that replaced the originally QQ-Z-325?
Would really appreciated your help.
Dave Gresham
Manufacturing Engineer – Basingstoke, Hampshire, UK
April 15, 2013
A. Hi Dave,
BS 3382 always used to be the call out. That has now been superseded by BS 7371.
Brian Terry
Aerospace – Yeovil, Somerset, UK
April 23, 2013
Hi Brian,
thanks very much for your help, these standards do get a bit confusing!
Dave Gresham
– Basingstoke, Hampshire, UK
April 29, 2013