plating, anodizing, & finishing Q&As since 1989
Plating specification QQ-Z-325
Q. Dear sir,
I have been asked to zinc plate a cold rolled steel sheet fabricated part according to Zinc plating standard QQ-Z-325 Type II Class I colour Yellow. Does this standard explain the thickness in micron, if so please inform.Rajiv maheshwari
manufacturers of Steel fabricated components - Aligarh, U.P., India
A. I only can find QQ-Z-325C which is classification
one Thickness 25 µm or 1.0 mil two " 13 " or 0.50 " three " 5 " or 0.02 " Class mil External Untreated threads surfaces 0.50 0.1-0.4 0.2-0.5 1 0.1-0.3 0.1-0.3 0.2-0.4 2 0.2-0.4 0.1-0.4 0.2-0.4 3 0.3-0.5 0.2-0.5 0.3-0.5 4 0.4-0.6 0.3-0.6 0.4-0.6 5 0.5-0.7 0.4-0.7 0.5-0.7
Note.This what I found in Plating Standards and Specifications. Please double check.Harshad vyas
- Alhambra California
A. Hello Rajiv!
Federal standards such as QQ-Z-325 are maintained by the General Services Administration, a part of the US Government. They chose to cancel this one back in March of 1982. While they did not supersede the specification, they did mention in the cancellation notice that ASTM has a fine document numbered ASTM B633 [affil link] that people can use for acquisition.
That specification correlates the thickness of the coating to the service that the part is expected to take. There is no simple "Class 1". So, I expect you'll have to ask your customer what thickness they want.
metallurgist - E. Aurora, New York
Q, A, or Comment on THIS thread -or- Start a NEW Thread