Views:0 Author:WGT Publish Time: 2021-12-13 Origin:WGT
The selection of good planetary reducer materials is conducive to improve the bearing capacity and service life of gear reducer.
According to the structural characteristics of precision reducer and the load properties of gear, hard gear should be widely used. There are many heat treatment methods to obtain hardened gears. Such as surface quenching, integral quenching, carburizing quenching, nitriding, etc., shall be selected according to the characteristics of gear reducer.
1. Surface quenching
There are two common surface quenching methods: high frequency quenching (for small size gears) and flame quenching (for large size gears). When the hardened layer of surface quenching includes the bottom of tooth root, its effect is good. The tooth surface hardness can reach 45-55hrc
The use of nitriding can ensure that the gear can achieve high tooth surface hardness and wear resistance under the condition of as little deformation as possible. After heat treatment, no finishing machining is carried out, and the bearing capacity is improved.
3. Carburizing and quenching
Carburized and quenched gears have relatively large bearing capacity, but finishing process (gear grinding) must be used to eliminate heat treatment deformation to ensure accuracy.
Carburized and quenched gears are usually made of alloy steel with carbon content of 0.2% - 0.3% before carburization. The hardness of tooth surface is often in the range of 58-62hrc. If it is lower than 57hrc, the hard surface strength decreases significantly, and if it is higher than 62hr, the brittleness increases. The hardness of the carburized and quenched gear gradually decreases from the gear surface to the deep layer, and the effective carburizing depth is specified as the depth from the surface to the hardness of 5.25hrc.
The effect of carburizing and quenching on the bending fatigue strength of gears not only improves the hardness of the core, but also lies in the residual compressive stress on the surface. It can reduce the stress in the maximum compressive stress area, so the tooth root cannot be ground during tooth grinding