Grinding wheel hardness: It reflects how easily the abrasive grains fall off the surface of the grinding wheel under the action of the grinding force. It and the hardness of abrasive grains are two different concepts.
The following principles can be considered when selecting the hardness of the grinding wheel：
1. Workpiece hardness: the harder the workpiece material, the softer the grinding wheel hardness should be selected, and the softer the workpiece, the harder grinding wheel hardness should be selected.
2. Processing contact surface: the contact between the grinding wheel and the workpiece When the surface is large, a soft grinding wheel should be used to make the abrasive particles fall off faster to avoid burns on the surface of the workpiece.
3. Fine grinding and profile grinding: When fine grinding and profile grinding, a harder grinding wheel should be used to ensure the necessary shape of the grinding wheel. Accuracy.
4. Grain size of the grinding wheel: the larger the size of the grinding wheel, the lower the hardness is to avoid the surface structure of the grinding wheel from being blocked by the grinding debris.
5. Workpiece material.
If the grinding wheel is too hard, the blunt abrasive grains will not fall off in time, which will generate a large amount of grinding heat and cause burns to the workpiece. On the contrary, if the grinding wheel is not hard enough, the abrasive particles will fall off too quickly to fully exert its cutting effect.
