Hard
grinding of chrome steel balls
The grinding method, by using wheels of grinding machine after heat treatment, to grind the balls are called hard grinding. The purpose is to remove the defects of soft grinding, to remove the defects of surface oxidation, decarburization, deformation and troostite structure defects generated during heat treatment, so that to further improve the precision and surface quality.
During or after grinding process，
1. Surface quality checking.
2. Cold acid pickling and burning defects checking.
Burning defects can be divided into second tempering burning and second quenching burning. After cold acid pickling, second tempering burning shows black color, while second quenching burning shows grey martensite in the middle and black troostite in rim.
