In many cases, the bolts just pulled out of the cold heading machine can not be delivered to the customers immediately. We must carry out special metal surface treatment according to the customer satisfaction before considering the customer's hard requirements for some commodities. Then, what is the general metal surface treatment and what are their respective functions?

After the metal surface treatment of stainless steel rivets is solved by mechanical equipment and organic chemistry, the purpose of all aluminum lantern core pulling rivets is to endow the commodity surface with beautiful appearance and corrosion resistance. According to the soil layer on the surface of standard parts such as bolts, it can produce a layer of protective layer thickness to protect human body on the surface of commodity. At present, the common methods of metal surface treatment are as follows:

1. Electroplating process: immerse the component receiving the electroplating process in a solution with metal compounds to be deposited, and dissolve and deposit the electroplating process metal materials on the components according to the current according to the plating solution. The general electroplating process includes hot dip galvanizing, copper, nickel, chromium, copper nickel alloy, etc., sometimes including black (bluing) and phosphating treatment.

2. Hot dip galvanizing: it is carried out by immersing the carbon steel members into a bath which dissolves zinc at about 510 ℃. As a result, the automobile black rivet is that the iron zinc alloy material on the surface of the iron casting gradually changes into the passivation treatment zinc on the surface of the commodity surface, and the hot-dip aluminizing film is a similar whole process.

3, mechanical equipment plating: according to the particles of coated metal materials to impact the surface of the commodity, and the coating is cold welded to the surface of the commodity.

Generally, electroplating process is mostly used for screws, but hot-dip galvanizing must be applied to hexagon wood screws used in electric power engineering, highway and other outdoor areas. The cost of electroplating process is generally 1.2-1.6 yuan / kg, and hot-dip coating is generally 2-2.5 yuan / kg, which is relatively high.