The general selection principle of grinding wheel hardness as below:

1.When grinding hard materials, select a softer grinding wheel, whereas when grinding soft materials, a harder grinding wheel should be selected.

2.When the grinding wheel has a large contact area with the workpiece, a softer grinding wheel should be selected.

3.When grinding materials with poor thermal conductivity, a softer grinding wheel should be selected.

4.When refined grinding, precision grinding, ultra-fine grinding, forming grinding, the selection of a harder grinding wheel.

5.Mirror grinding, slow feed grinding, generally choose ultra-soft grinding wheel.

6.When grinding rubber, resin and other organic materials, you should choose a softer grinding wheel.

7.In machining, the hardness grade of commonly used grinding wheels is generally between H-N.Grinding billets or castings generally at Q-level.