Heat Treatment Method Of Planetary Reducer
Choosing a good planetary reducer material is conducive to improving the bearing capacity and service life of the gear reducer.
In view of the structural characteristics of the precision reducer and the load characteristics of the gear, hardened gears should be widely used. There are many heat treatment methods to obtain hardened gears. Such as surface quenching, overall quenching, carburizing quenching, nitriding, etc., should be selected according to the characteristics of the gear reducer.
1. Surface hardening
Common surface quenching methods include high frequency quenching (for small-size gears) and flame quenching (for large-size gears). The effect is best when the hardened layer of surface hardening includes the bottom of the tooth root. The tooth surface hardness can reach 45-55HRC.
2. Nitriding
Nitriding can ensure that the gear can achieve high tooth surface hardness and wear resistance under the condition of minimum deformation. After heat treatment, the best finishing is no longer performed, which improves the load-bearing capacity.
3. Carburizing and quenching
The carburized hardened gear has a relatively large load-bearing capacity, but the finishing process (tooth grinding) must be used to eliminate heat treatment deformation to ensure accuracy.
Carburized and hardened gears are commonly used alloy steels with a carbon fraction of 0.2%-0.3% before carburization. The hardness of the tooth surface is often in the range of 58-62HRC. If it is lower than 57HRC, the hard surface strength will decrease significantly, and it will be brittle if it is higher than 62HR. increase. The hardness of carburized and hardened gears gradually decreases from the surface of the gear to the deep layer, and the effective carburizing depth is specified as the depth from the surface to the hardness of 5.25HRC.
The role of carburizing and quenching in the bending fatigue strength of gears not only increases 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 root part of the tooth cannot be ground when grinding the tooth.