The surface treatment of steel parts generally has two types: alkaline oxidation method and acid oxidation method. Acid oxidation is also known as "blue". The purpose is to form an oxide film on the metal surface to prevent the metal surface from being corroded. The acid oxidation method is also called “phosphating treatment” (this method is adopted by most military companies in the world), which has better resistance than blue. Abrasion and corrosion resistance. The oxide film formed on the surface of the steel product after being treated with "blue" is mainly composed of triiron tetroxide. It is dark blue or dark black.

The latitude of the temperature required for blackening is large, and a good surface can be obtained between about 135 degrees Celsius and 155 degrees Celsius, but the length of time required is somewhat short. In actual operation, it is necessary to pay attention to the quality of the rust and degreasing of the workpiece before blackening, and the passivation immersion oil after blackening. The quality of blackening is often changed by these processes.

Metal "blue" liquid
Alkaline oxidation or acid oxidation is used; an oxide film is formed on the surface of the metal to prevent corrosion of the metal surface. This process is called "blue". The oxide film formed on the surface of the ferrous metal after "bluening" treatment has an outer layer mainly composed of triiron tetroxide and an inner layer of ferrous oxide.

Shandong Second Machinery Co., Ltd. was established in 1965. The factory is dedicated to the research and development of military equipment products. The production of black oxidized steel parts is a very common surface treatment method for gun parts. Welcome to contact us worldwide.