Study on the structure and properties of a novel mini-sized high Cr mill balls

To substitute bearing steel mill balls used in magnetic material powder production, a novel mini-sized high Cr mill balls with sizes in the range Ø 6.35–7.14 mm were developed. The structure, abrasion resistant properties and application performance of the balls were investigated in the present study. It was shown that both higher hardness (HRC 65–67) and longer impact fatigue life could be achieved through suitable composition design and heat treatment. The service life of the novel balls in the stirring ball mills was at least four times that of bearing balls.