How to Choose the Hardness of Grinding Wheel?

The selection for the hardness of grinding wheel depends mainly on the workpiece materials, grinding efficiency and machining surface quality.

The hardness refers to the complexity that abrasive grains of grinding wheel fall off under the action of external force. In order to meet the requirements of different workpiece materials, the hardness is divided into different hardness level when manufacturing grinding wheel.

If the hardness of grinding wheel is hard, dull abrasive grains will be not easy to fall off. As a result, grinding wheel will be easy to jam, so the grinding heat will increase that will cause the workpieces burned easily, going with low grinding efficiency and surface quality; If the hardness is too soft, abrasive grains will fall off when they are sharp, which will increase grinding wheel wear. It is also easy to lose correct geometry, and affects the precision of workpieces. Therefore, the selection of grinding wheel hardness should be appropriate, but also needs to consider the contact area of grinding wheel and workpieces, the shape of workpieces, grinding way, cooling way and other factors.

The following principles for reference about how to choose wheel hardness: A. When grinding soft materials, we should choose harder grinding wheels; When grinding hard materials, we should choose soft grinding wheels; B. When grinding soft and tough non-ferrous metals, we should choose softer hardness; C. When grinding some materials with low thermal conductivity, we should choose soft grinding wheels; D. In the same grinding conditions, the hardness of resin bonded grinding wheel should be higher than that of ceramic bonder grinding wheel about 1 ~ 2 level; E. If the rotation speed of grinding wheel is high, the hardness of grinding wheel should be softer.