Abrasive hardness classification
The hardness of the abrasive tool mainly depends on the amount of the binder added and the density of the abrasive. The abrasive particles are easy to fall off, indicating that the hardness of the abrasive is low; otherwise, the hardness is high. The hardness grades are generally divided into seven levels: super soft, soft, medium soft, medium, medium hard, hard and super hard. From these levels, several small levels can be subdivided. The method for determining the hardness of the aluminum flat cutting disc is more commonly used by a hand cone method, a mechanical cone method, a Rockwell hardness tester method, and a sand blast hardness tester.
The hardness of the abrasive tool has a corresponding relationship with its dynamic elastic modulus, which is advantageous for determining the dynamic modulus of the abrasive tool by the audio method to indicate the hardness of the abrasive tool. In the grinding process, if the material of the workpiece to be ground is high in hardness, a grinding tool having a low hardness is generally used; and vice versa, a grinding tool having a high hardness is used.
Abrasives are roughly classified into three types: compact, medium, and loose. Each class can be subdivided, etc., and is distinguished by the organization number. The larger the abrasive tissue number, the smaller the volume fraction of the abrasive in the abrasive tool, and the wider the gap between the abrasive grains, indicating that the tissue is looser. Conversely, a smaller organization number indicates a tighter organization. The abrasive material of the looser structure is not easy to passivate when used, and has less heat during the grinding process, and can reduce the heat deformation and burn of the workpiece. The abrasive grains of the tighter structure are not easy to fall off, which is beneficial to maintain the geometry of the abrasive tool. The organization of the abrasive tool is controlled only by the abrasive formula at the time of manufacture, and is generally not measured.