The commonly used surface treatment of fasteners includes phosphating treatment, galvanizing treatment, dacromet treatment, hot dip galvanizing treatment, plastic spraying treatment, anodizing treatment, electrostatic spraying treatment, heat treatment and carburizing treatment.
Phosphating : black or black-gray, forming a phosphating film on the surface of the fastener to improve wear resistance. The uniformity of the phosphating film is good, it has almost no impact on the size, which is conducive to the later painting process, and is suitable for fasteners in the box in contact with the oil, and fasteners with high requirements for the thread pass gauge or the painting requirements in the later sequence.
Electroplating is a common surface treatment method for fasteners. A metal film is attached to the surface of fasteners to improve their corrosion resistance. Common electroplating methods include zinc plating, nickel plating and chromium plating. Zinc plating can effectively prevent fasteners from rusting and is suitable for most common fasteners. Nickel plating can improve the corrosion resistance of fasteners and is suitable for fasteners used in corrosive environments. Chrome plating can increase the wear resistance and appearance quality of fasteners, and is suitable for fasteners with high requirements.