GMW GMW4700 PDF

This specification covers the basic requirements for barrel or rack electrodeposited zinc alloy plating over a ferrous substrate. Various alloy platings with supplementary treatments are covered by this specification.

Zn- Ni plating is available in two types: Type A and Type B. Zn- Ni Type B plating has higher corrosion resistance performance than Zn- Ni Type A. Zn- Ni Type B must have supplementary sealers on top of the conversion coating. The engineering drawing with GMW4700 Zn- Ni without any type will default to Type A. In case of Type A electrodeposits may be applied with or without supplementary sealers meeting the performance requirements. Table 1 lists the zinc alloy finishes covered by this specification.

This specification covers functional requirements only. Cosmetic requirements such as brightness, shades, tint, etc. are not defined. Material approved to this specification may not meet special cosmetic/ appearance requirements, and will have to be agreed upon by the purchaser and applicator.