The hardness of the abrasive tool refers to the difficulty of the abrasive particles falling off the surface of the abrasive tool under the action of external force. The hardness of the abrasive tool mainly depends on the amount of bonding added and the density of the abrasive tool. The abrasive particles are easy to fall off, indicating that the hardness of the abrasive tool is low, on the contrary, it means the hardness is high.

1.In the grinding process, the abrasive tool with low hardness is generally used to grind harder workpieces, otherwise, the abrasive tool with high hardness is selected.

2.When grinding, when the contact surface between the workpiece and the abrasive tool is large or the feed rate is large, the hardness of the abrasive tool should be selected softer. In order to ensure the accuracy of the geometric shape of the workpiece, the hardness of the abrasive tool can be appropriately increased during forming grinding.

3.When grinding workpieces with poor thermal conductivity and sharpening tools, in order to avoid burns, annealing, and the hardness of the abrasive tools should be softer.

4. In high-speed grinding, the hardness of the abrasive tool should be softer; the hardness of the abrasive tool for dry grinding should be softer than that for wet grinding.

Inspection of Abrasive Tools Hardness

There are two methods to check the hardness of abrasive tools: hand taper method and hardness tester. Commonly used hardness testers include sandblasting hardness tester, Rockwell hardness tester, mechanical cone, and acoustic frequency hardness tester. China national standards GB/T2490-2003 and GB/T2491-2003 stipulate that for ceramic and resin bond abrasives with particle size F36-F150, the hardness shall be measured with a sandblasting hardness tester; for F180-1200 ceramic bond and resin bond abrasives, the hardness is measured by Rockwell hardness tester. For F30 rough abrasive tools and small grinding heads, small grinding wheels and other abrasive tools that can not be measured by sandblasting hardness tester or Rockwell hardness test are commonly used to determine the hardness. But it must be compared with standard grinding wheel hardness blocks. For coarse-grained abrasive tools, it can be partially solved by the audio method.