NINGGUO KAIYUAN have much experience on cement mill grinding media and we really do lots of scientific experiment to produce various high chrome mill balls to adapt the coal mill and cement mill.As grinding head of wind swept coal mill added automatic heating system,the grinding temperature is often high up to about 200 degrees.Under this special working condition,it is a extremely harsh test for grinding media.In order to guarantee the mill balls quality,NINGGUO KAIYUAN adopt the heat treatment with automatic oil quenching, automatic temperature control, automatic time control.Meanwhile the control of manganese content is very reasonable, “manganese”,less content (0.2 0.8) less residual austenite, it is completely scientific and reasonable to solve and avoid much breakage appearance and high wear rate under bad working conditions.