Black surface treatment of screws

In addition to the blackening and black screw phosphating treatment of steel, the surface treatment of screws also has blackening and black phosphating, letting the screw manufacturer introduce it to everyone.

Blackening: it is a common means of metal heat treatment. The principle is to produce a layer of oxide film on the metal surface to isolate the air and achieve the purpose of anti-rust.When the appearance requirement is not high, can use black processing, the surface of steel parts blackening treatment, also have been called hair blue.Bluing is a kind of chemical surface treatment, its main function is formed in the surface layer of dense oxide film, prevent the workpiece on the corrosion rust, improve the wear resistance, it is a kind of surface treatment, not for any impact on the internal organization, it is not heat treatment, quenching and a fundamental difference between the two.

Non standard black screw

Special black screw

Black screw phosphating: a process in which chemical and electrochemical reactions form a phosphate chemical conversion film, and the resulting phosphate conversion film is called a phosphating membrane.The main purpose of phosphating is to provide protection to the base metal and prevent the corrosion of metal to a certain extent.Used to paint the bottom before painting, improve the adhesion and corrosion resistance of the film layer;It is used in the process of metal cold machining.Phosphating is a commonly used pretreatment technique, which should be treated by chemical conversion film, which is mainly used in the phosphating of steel surface, and non-ferrous metals (such as aluminum and zinc) can also be phosphatized.Artifacts (steel or aluminum, zinc immersion phosphating liquid (some acid phosphate solution), formed in the surface sediment layer of insoluble crystalline phosphate conversion membrane process, called phosphide.

Socket Shoulder Screw

Machine screw

If you want to know more about the surface treatment of black screw, continue to pay attention to the SSTong screw manufacturer’s next analysis!