How to form grinding metamorphic layer of self-aligning roller bearing

When using self-aligning roller bearings, burns or cracks often occur. Generally, such problems as poor lubrication or high or low speed of rotation will occur first. In fact, in addition to these common problems, there is another phenomenon that high temperature quenching or secondary quenching will also cause this series of problems, and the occurrence of these problems will also affect the grinding metamorphic layer of self-aligning roller bearings. When grinding in use, the grinding wheel and the workpiece will consume a lot of energy after touching each other, and these so-called energy is grinding heat. When the grinding heat reaches a certain amount, it will cause local high temperature. From experiments or practice, the instantaneous temperature of infrared method and thermocouple method can be deduced and calculated according to the theoretical formula of heat transfer using linear motion heat source, and this temperature can reach 1000~1500 ℃ in the grinding area. At this high temperature, the surface of the self-aligning roller bearing will be deeply oxidized at high temperature, and such oxidation is like high-temperature tempering or secondary quenching, so it is easy to cause burns and even cracks of the self-aligning roller bearing at this high temperature.

As for the mark of grinding quality, there is a direct relationship between the thickness of oxide layer and grinding process. When the steel surface interacts with the oxygen in the air under the action of instantaneous high temperature, an extremely thin layer of ferrite will be formed. It should be noted here that the thickness of the tested oxide layer corresponds to the total thickness of the grinding metamorphic layer on the surface of the self-aligning roller bearing, which is an important sign of grinding quality.

The main factor that can cause the grinding deterioration layer of the self-aligning roller bearing is that the instantaneous high temperature in the grinding area will promote the surface of the self-aligning roller bearing to reach the melting state, and form an extremely thin layer of amorphous structure layer through rapid cooling. This amorphous structure layer has high hardness and toughness, but this structure layer also has a disadvantage, that is, it is only about 10 nm, which is easy to be removed in the process of precision grinding, With the instantaneous high temperature in the grinding zone, if the austenitizing temperature has not been reached, the heating temperature will continue to rise, resulting in grinding deterioration of the surface of the self-aligning roller bearing, thus reducing the hardness value of the self-aligning roller bearing.