Choosing good planetary gearbox materials is beneficial for improving the load-bearing capacity and service life of gear reducers.

Due to the structural characteristics of precision reducers and the load properties of gears, hard toothed gears should be widely used. There are many methods for obtaining hard tooth surface gear heat treatment. Surface quenching, integral quenching, carburizing quenching, nitriding, etc. should be selected according to the characteristics of the gear reducer.

Gear reducer

1. Surface quenching

The common surface quenching methods include high-frequency quenching (for small-sized gears) and flame quenching (for large-sized gears). When the hardened layer of surface quenching includes the bottom of the tooth root, its effect is excellent. The tooth surface hardness can reach 45-55HRC

2. Nitriding

The use of nitriding can ensure that the gear achieves high tooth surface hardness and wear resistance under the condition of minimal deformation. After heat treatment, no further precision machining is required, which improves the bearing capacity.

3. Carbonization and quenching

Carburized and quenched gears have relatively high load-bearing capacity, but precision machining processes (gear grinding) must be used to eliminate heat treatment deformation and ensure accuracy.

Alloy steel with a pre carburizing carbon fraction of 0.2% -0.3% is commonly used for carburizing and quenching gears, and its tooth surface hardness is often in the range of 58-62HRC. If it is lower than 57HRC, the hard surface strength significantly decreases, and if it is higher than 62HR, brittleness increases. The hardness of carburized and quenched gears gradually decreases from the surface to the deep layer, and the effective carburization depth is defined 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 is not only to increase the hardness of the core, but also to reduce the residual compressive stress on the surface. It can reduce the stress in the high compressive stress zone, so the tooth root cannot be ground during gear grinding