The aluminum oxide abrasive is chiefly used for grinding
* high speed steel
* carbon steel
* wrought iron

When grinding high carbon steel,
* Grinding at high speed results in the reduction of chip thickness and cutting forces per grit.
* aluminum oxide wheels are employed.
* the grinding wheel has to be of open structure.

When the cutting edge of a grinding wheel takes a glass-like appearance due to wear of abrasive grains then it is called glazing of the grinding wheel. Glazing decreases the rate of grinding. The glazing in the grinding wheels takes place when the wheel is too hard or it revolves at a very high speed.
Thus the glazing may be decreased by using a softer wheel or decreasing the wheel speed.
The process of changing the shape of grinding wheel as it becomes worn due to breaking away of the abrasive and bond is called truing.
The process of improving the cutting action of the grinding wheel is called dressing.