According to the skin formation mechanism on the grinding surface of cylindrical roller bearing, there are two main factors that have great influence on the grinding skin, namely grinding heat and grinding force.Due to the author's limited knowledge, the following sections will now discuss why cylindrical roller bearings lose their effectiveness in terms of grinding force.
How does grinding heat occur?In the grinding process, the cylindrical roller bearing brings energy and a lot of grinding heat when the grinding wheel is in contact with the workpiece.As a result, a portion of the grinding zone is suddenly heated.Results of changes in the working surface, such as amorphous structure, high tempering, secondary quenching, cracking, combustion and other high-temperature oxidation.For cylindrical roller bearings, the failure of surface oxide layer, amorphous structure layer and high temper layer is the relative main reason.
So-called surface forming oxide layers react instantaneously between the steel surface and oxygen in the air at high temperatures.The oxide layer is very thin.This is only about 20 to 30 nanometers.What one should note is that the thickness of the oxide layer corresponds to the total thickness of the surface grinding skin.From this point, it can be concluded that the oxide thickness is directly related to the grinding process.At the same time, it is an important index for grinding quality.
For the amorphous layer, it is the moment the working surface is formed because of the high temperature melting state.The flow of molten metal molecules works evenly on the surface, while it is cooling at a very fast rate as the base metal drops.The amorphous layer is also relatively thin, but its hardness and toughness are very high.As it is only 10 nm, it is easy to remove during the precision grinding process.
The third is high temper layer.The instantaneous high temperature in the grinding zone makes the surface temperature compare to the tempering temperature of the workpiece.At the austenitizing temperature which is not reached, the surface temperature of cylindrical roller bearings increases step by step.At the same time, the hardness decreases.Higher heating temperatures increase and more severe hardness decreases.