The low quenching cooling rate is the cause of insufficient quenching hardness of the gear, uneven hardness and insufficient hardening depth. However, depending on the material, shape and heat treatment requirements of the actual quenching gear, it can be divided into low temperature and low temperature in the high temperature stage. Insufficient conditions such as insufficient cooling rate in the stage and insufficient cooling rate in the low temperature stage. such as. For medium and small gears, the quenching hardness is often caused by insufficient cooling speed in the middle and high temperature stages. When the gears with large modulus require deeper hardened layers, it is necessary to increase the low temperature cooling rate.
For the quenching oil, in general, the vapor film phase of the oil is short, the medium temperature is fast, and the low temperature cooling speed is fast, and a high and uniform quenching hardness and a sufficient hardening depth are often obtained.
The mounting method of the workpiece also has a significant effect on the quenching cooling effect. In order to make the quenching oil flow smoothly, the quenching oil tank is equipped with a stirring device to obtain better results.
Increasing the low temperature cooling rate of the quenching medium used can often increase the depth of the hardened layer. In the case of the same carbon concentration distribution, the quenching oil with higher cooling rate is often used to obtain a deeper quench hardened layer. Therefore, after quenching oil with a fast cooling rate, the carburizing time of the workpiece can be shortened accordingly. The required depth of the hardened hardened layer can be obtained. The greater the depth of the required carburized hardened layer, the more obvious the effect of shortening the carburizing time by this method.
