Grinding Wheel is the most important type of abrasive in grinding. The grinding wheel is a porous body made by adding a binder to the abrasive, by pressing the billet, drying and roasting. Because of the different abrasive, binder and manufacturing processes, the characteristics of the grinding wheel vary greatly, so it has important influence on the machining quality, productivity and economy. The characteristics of grinding wheel are mainly determined by the factors such as abrasive, particle size, binder, hardness, microstructure, shape and size.
The hardness of the grinding wheel refers to the difficulty of peeling off the abrasive grains on the surface of the grinding wheel under the action of grinding force. The hardness of the grinding wheel is soft, which indicates that the abrasive grains of the grinding wheel are easy to fall off and the hardness of the grinding wheel is hard to fall off. The hardness of the grinding wheel and the hardness of the abrasive are two different concepts. The same abrasive can be made of different hardness of the grinding wheel, it mainly depends on the performance of the binder, quantity and grinding wheel manufacturing process. The remarkable difference between grinding and cutting is that the grinding wheel has "self sharpness" and the hardness of the grinding wheel, in fact, is the choice of the grinding wheel's own sharpness, hope that the sharp abrasive particles do not fall off too early, also do not wear blunt not to fall off.
The general principle of choosing grinding wheel hardness is: When processing soft metal, in order to make the abrasive don't fall off prematurely, choose hard grinding wheel. When processing hard metal, in order to be able to timely wear blunt abrasive particles off, thus exposing the sharp edges of the new abrasive particles (that is, from the sharpness), the selection of soft grinding wheel. The former is because in the grinding of soft materials, grinding wheel work abrasive wear is very slow, do not need to be too early to disengage; the latter is because in grinding hard materials, grinding wheel work abrasive wear faster, need a faster update.