In the process of use, the spring shall be subject to the corrosion of harmful gases and work under the corrosion fatigue conditions, causing local corrosion damage on the steel wire surface to form stress concentration, and gradually expanding the corrosion fatigue cracks. The oxidation treatment can make the shell pulling hook spring have certain corrosion resistance.
After oxidation treatment, the hook spring can form a dense oxide film on the steel wire surface, which can prevent the corrosion of gunpowder gas.
Oxidation treatment can reduce the friction of hook spring. In the shooting process, the hook spring is repeatedly stretched and compressed in the spring chamber, and at the same time, it forms friction with the spring chamber and generates friction heat, which is one of the reasons for the early failure of the shell pulling hook spring.
After the hook spring is oxidized, the tiny loose holes of the oxide film can store oil and lubricate the spring; The thermal conductivity of the oxide film is much lower than that of the shell pulling hook spring steel wire, which has a good thermal protection effect and is also conducive to preventing the early failure of the shell pulling hook spring.
After the spring has been oxidized, through more than 40 life tests, the shell pulling hook spring has not broken. Practice has proved that the use of oxidation treatment for the shell pulling hook spring can improve its service life.