The hardness of grinding wheels and their selection

The hardness of a grinding wheel refers to the firmness of the abrasive particles and adhesive on the surface of the wheel. The hardness of the grinding wheel is soft, indicating that the abrasive particles are prone to detachment, while the hardness of the grinding wheel is hard, indicating that the abrasive particles are difficult to detach. The hardness of grinding wheels and the hardness of abrasives are two different concepts. The same abrasive can be used to make grinding wheels with different hardness, which is mainly determined by the performance and quantity of the binder, as well as the manufacturing process of the grinding wheel. The significant difference between grinding and cutting is that grinding wheels have "self sharpness". Choosing the hardness of the grinding wheel is actually choosing the self sharpness of the grinding wheel, hoping that even sharper abrasive particles do not fall off too early, nor do they become dull and do not fall off. The general principle for selecting the hardness of grinding wheels is: when processing soft metals, in order to prevent the abrasive from falling off prematurely, a hard grinding wheel is selected. When processing hard metals, in order to timely remove dull abrasive particles and expose new abrasive particles with sharp edges (i.e. self sharpening), a soft grinding wheel is selected. The former is because when grinding soft materials, the working abrasive wear of the grinding wheel is slow and does not require too early detachment; The latter is because when grinding hard materials, the working abrasive grains of the grinding wheel wear out quickly and require quick updates. During precision grinding, in order to ensure grinding accuracy and roughness, a slightly harder grinding wheel should be selected. When the thermal conductivity of the workpiece material is poor and prone to burns and cracks (such as grinding hard alloys), the selected grinding wheel should be softer.