Automotive gearbox gear materials not only need to have good strength, toughness, and wear resistance, but also require small deformation and high machining accuracy. In the heat treatment process of gears, in addition to general quenching and tempering, various surface hardening processes such as carburizing quenching, nitriding treatment, and high-frequency quenching are also used. The following technical requirements for automotive gearbox gear materials are:
1) Adequate core hardenability, surface hardness, and depth, ensuring that there are no undercooled austenite decomposition products in the carburized layer and core during gear carburization and quenching;
2) The size deformation of gears after carburization and quenching is small and uniform, making it easy for subsequent precision machining.
The commonly used domestic materials for automotive gearbox gear materials include 20CrMnTi, 20CrMo, 20MnCr5, 25CrMnS4, etc.
