1)hardness Surface hardness of forged ball ranges from hrc55 to hrc67. Core hardness of forged ball ranges from hrc50 to hrc55. Average volume hardness (avh) ranges from hrc55 to hrc63. All requirements about hardness can be customized according to different grinding condition. 2)density Average density is 7.85g/cm3. Consistency is higher than ordinary ones. 3)component analysis Raw material is high carbon alloy steel, and the promotion of alloy elements is under 5%. 4)impact value Impact toughness value is more than 12j/cm2 5)metallographic structure Tempered martensite forms when tempered. The best microstructure is fine needle martensite. 6)breakage rate Actual breakage rate is not greater than 0.5% and close to 0. 7)raw material As we know, the quality of forged grinding piece depends on the material by 80%. Our products use high-quality round steel from national large-scale steel mill to insure the quality of our products.