Abrasives must have high hardness, heat resistance, thermal stability and chemical stability, but also a certain toughness, in order to be able to bear a certain grinding force.

Abrasive selection principle

Aluminium abrasives with greater toughness are selected for grinding materials with higher tensile strength. The materials with low tensile strength were ground to choose the silicon carbide abrasive with high brittleness.

In addition to considering the tensile strength of the workpiece material, in the selection of abrasive, the hardness of the workpiece material is also the main choice. Generally speaking, the abrasive hardness should be 2-4 times higher than the hardness of the workpiece material, otherwise, the lower hardness of the abrasive grains in the process of high-speed cutting will quickly passivate and lose cutting ability, make the grinding wheel durable too low and affect the cutting efficiency, and processing quality can not be guaranteed. Therefore, the higher the hardness of the workpiece material, the higher the hardness of the abrasive should be.

The selection of abrasives should also take into account the possible chemical reactions of the grinding process system. In the grinding contact area, the abrasive, binder, workpiece material, grinding fluid and air are easy to produce spontaneous chemical reactions under the catalysis of grinding temperature and grinding force. The test shows that the wear of silicon carbide grinding tool is faster than that of corundum grinding tool when grinding steel. The main reason is the strong chemical reaction between silicon carbide abrasive and steel.

In addition, when choosing abrasives, consider the thermal stability of abrasives. In the grinding of some difficult materials, grinding area easy to produce higher temperature, used abrasive should have better high temperature hardness retention.