Heat Treatment Technology in Automotive Bearings

Bearing, which is widely used in machinery industries, is an important basis for mechanical connections. It is said that when there is rotation, there is a bearing. At the same time, as a main means of transport, car plays a significant role in our daily life. Thus, the automobile industry also becomes a pillar industry in China where bearings play an important role. Bearing products can be seen in many security devices of cars such as the steering gear, engine and gearbox, etc. As a branch of bearing category, the automotive bearings have many special properties such as high-speed rotation and shock resistance which have great effect on passengers, drivers and safety of the vehicle itself.

Heat treatment is a key process during the manufacturing process of the automotive bearings. Its processing quality and the quality of raw materials are two important factors that affect the bearing life. The following is a brief introduction of the heat treatment technology on the car bearings. The introduction will lay basis on the automotive bearing materials, heat treatment design, heat treatment equipment, heat treatment technology and the development trends of the heat treatment, etc. Let us see some of them.

The quality of the bearings is the most important factor that determines the service life of the bearing products. The material is the main reason for the gap between China’s automotive bearings and that of foreign countries. Besides, the bearing design, process level and process equipment are other factors. Although China has proposed many useful standards, full implementation is still very difficult because we subject to many elements like domestic steel smelting technology and costs.

With the extensive application of vacuum degassing, the control of the oxygen content of our bearing steels has greatly improved which is close to foreign standards. However, there is still a large gap in the uniformity of carbide, and carbide network control. All of them lead to the imperfection of domestic automotive bearings. As a result, the service life, reliability, and consistency of bearings are inferior to foreign bearings.

There is also a lack of differential designs. Advanced bearing design should be based on the bearing service environments so as to meet the requirements of the actual condition of bearings. Domestic individual and differential bearing design is still insufficient. In addition, heat treatment of bearing design is also an important factor that affects bearing life. Bearing includes four main pieces. There are outer ring, inner ring, rolling element and cage. Foreign bearing companies have special hardness requirements for the outer race and rolling elements of bearing products. But there is still a restriction on the hardness design of the bearings.