The surface treatment of screws, according to the different requirements of their goods, there are many surface treatment methods. According to the surface treatment methods can be divided into many, such as painting, electroplating, electroless plating, vacuum coating, immersion plating, anodizing, sandblast hardening, coating, vapor deposition, carburizing, nitriding, surface hardening and so on. Nowadays, compared to the popularity of the public, the usual surface treatment methods are as follows:
Electroplating: Immersing the parts subjected to electroplating in an aqueous solution rich in deposited metal compounds and passing current through the electroplating bath to separate and accumulate the electroplated metals on the parts. Galvanizing, copper, nickel, chromium, copper-nickel alloys, etc. are usually electroplated, and sometimes black, phosphatized, etc. are included. Hydrogen embrittlement easily occurs during electroplating and has a great influence on the mechanical strength of the workpiece.
Mechanical plating: Mechanical plating consists of mixing activator, metal powder, impacting medium (glass microbeads) and a certain amount of water into a slurry, and putting it into the drum together with the workpiece. With the mechanical energy effect of roller rolling, the activator is With the mechanical impact of the impact medium (glass microbeads), the zinc coating gradually forms on the surface of the iron base at room temperature.
Hot-dip galvanizing: It is completed in a plating tank in which molten steel is immersed in a temperature of approximately 510°C. As a result, the iron-zinc alloy on the surface of the steel gradually becomes a passivation zinc on the outer surface of the commodity. However, due to the high temperature during hot-dip plating, steel products are susceptible to high temperature annealing.