The GMW 4205-0 standard specifies requirements for corrosion resistant black organic coatings on Eletroplating Zinc-Ferroalloys, Nickel Alloys and/or Zinc-Nickel Alloys substrates. The coating system does not contain chromium and needs to meet the requirements of GMW 3059. It is mainly used for small steel parts such as bolts, screws and nuts. The coatings should have a uniform black Appearance and adequate corrosion resistance with a thickness not exceeding 45 μm. The standard also includes testing requirements for adhesion, weathering resistance, corrosion resistance and high temperature performance of the coatings to ensure their Reliability and durability in actual use. In particular, the use of coatings may affect the torque-tension relationship of the bolt, and it is recommended to conduct relevant research before application.