Will excessive temperature reduce the hardness of the ball bearing material?

Yes, excessive temperature can indeed reduce the hardness of ball bearing materials. Ball bearings are usually made of high hardness steel or ceramic materials to ensure their good load-bearing capacity and wear resistance under high load and high speed conditions. However, when the bearing is exposed to excessively high temperatures for a long time, the physical properties of the material, especially hardness, will change, thereby affecting the performance of the bearing.
The hardness and strength of metal materials usually decrease with increasing temperature. When the working temperature of ball bearings exceeds their designed working temperature range, the lattice structure of the material will be affected by thermal energy, causing changes in the atomic arrangement inside the metal, which in turn affects the hardness and strength of the material. For example, common materials such as high carbon steel and alloy steel are prone to softening at high temperatures. The steel of ball bearings will lose its original wear resistance and strength at high temperatures, resulting in increased friction, intensified wear, and increased risk of generating more heat during bearing operation.
For ceramic bearings, although ceramic materials themselves have good high temperature resistance and stability at high temperatures, if the temperature is too high, the brittleness of the material may increase, which can easily lead to cracks or other damages on the bearing surface, thereby affecting the performance of the bearing.