Surface treatment is the process of forming a cover layer on the surface of a workpiece by a certain method, the purpose of which is to impart a beautiful and anti-corrosive effect to the surface of the product. The surface treatment methods of screws and nuts are attributed to the following methods:
1. Electroplating: immerse the parts to be electroplated in an aqueous solution containing the deposited metal compound, and pass the current through the plating solution to precipitate and deposit the electroplated metal on the parts. Generally, electroplating includes galvanizing, copper, nickel, chromium, copper-nickel alloys, etc. Sometimes boiled (blue), phosphating, etc. are also included.
2. Hot-dip galvanizing: It is completed by immersing carbon steel parts in a zinc plating bath with a temperature of about 510 ° C. As a result, the iron-zinc alloy on the surface of the steel piece gradually becomes passivated zinc on the outer surface of the product. Hot-dip aluminizing is a similar process.
3. Mechanical plating: The particles of the coated metal are used to impact the surface of the product, and the coating is cold-welded to the surface of the product.