In order to choose the suitable material for high-speed gears,you should consider the following points:
1. The chemical composition, mechanical properties and machinability of the materials.
2. According to the working conditions of the high-speed gear, the steel number shall be determined by the heat treatment process (quenched and tempered or surface hardening).
3. Nickel, chromium, molybdenum or nickel-molybdenum steel should be used for high-speed gear with heavy load and high impact.
4. High-speed gears shall be of structural steel with hardenability.
5. The material of high-speed gear shall have higher purity and dimensional stability.
6. The material should be economical and reasonable.
The above content is taken from the "Gear Drive Design Handbook"