Basic situation of automotive gear steel in China

In China’s automobile industry, the materials used for gears in the gearbox have mainly used the gear steel series of the former Soviet Union for many years; In the 1960s and 1970s, in order to save Cr and Ni resources, China studied B steel and Si – Mn, Cr – Mo and Cr – Mn series steel. For rapid processing and convenient use, it also studied free cutting steel and nitriding steel. Due to the wide variety of gears, some gears have poor performance due to heat treatment or smelting, which brings some difficulties to production and use.

In the 1980s, in order to meet the needs of automobile gear localization, on the basis of digesting and absorbing foreign advanced technology and referring to foreign technical standards and the actual level of imported products, China’s automobile gear steel has successively added steel types similar to those of the United States, Japan and Germany, and developed 20mncr5, 16MnCr5, SCM415, SCM420, scm45h, SCM420H, 21nicrmo5h New steel grades such as 20Mn cr5ca B (equivalent to ZF7 steel in Germany); At the same time, the basic performance test of these steel grades, the practical research on the heat treatment process of forging blank and gear parts, and a lot of research and exploration work on improving the purity of gear steel have been done, and reliable experimental data have been obtained.

Since 1987, China’s special steel mills have provided tens of millions of tons of domestic gear steel to the automotive industry. Because the price of new gear steel is too high, it is not easy for users to accept; In addition, the subsequent smelting processes need to be adjusted and transformed accordingly, and the research on the properties of some materials is not in-depth. Therefore, there are still great obstacles to the popularization and application of imported gear steel.

At present, 20CrMnTi is still used most in China’s automobile industry, followed by 20Cr, 20CrMo and 20CrMnMo steel. Some automobile manufacturers directly introduce foreign steel to make gears, but the prices are relatively expensive.

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