The hardness of the abrasive agent is added depends on the amount of binding and the density of abrasive, abrasive grains easily fall off indication low hardness; vice versa, which means high hardness. Hardness level is generally divided into super-soft, soft, medium soft, medium, medium-hard, hard and superhard seven magnitude, from these levels can be subdivided in a number of small magnitude. Abrasive hardness measurement methods are more commonly used hand cone, mechanical cone method, Rockwell hardness measurement method and sandblasting assay.
The hardness of the abrasive and its dynamic modulus of elasticity has a corresponding relationship, which is conducive to the audio abrasive measured dynamic elastic modulus of said abrasive tools. In the double disc grindingprocess, if they areinternal grinding workpiece material hardness, generally used in low hardness abrasive; Conversely, the selection of high hardness abrasive.