Application: good quality used in mining, cement, power plant etc. capacity: 50, 000tons/year improvement: 1.diameter: 10mm-150mm. 2.high hardness: surface hardness of casting balls is up to 60-66 hrc and volume hardness of foundry steel balls is up to 60-63 hrc. 3.high impact toughness. 4.low broken rate: the actual broken rate is not higher than 1%. 5.wear-resistant: the grinding lost.