1.Forged steel grinding balls Size: 20mm-150mm Hardness: HRC50-65 Chemical elements: C: 0.52-0.65; Si: 0.15-0.37; Mn: 0.6-1.2; S & P: 0.04Max; Cr: 0.25Max. 2.Forged steel grinding balls (RCAB-1) Size: 20mm-150mm Hardness:HRC58-65 Chemical elements:C:0.7-0.9,Si:0.65-1.00,Mn:0.70-1.25, P/S:0.04Max,V:0.05-0.12 3.High chrome casting balls Size: 20mm-120mm Hardness:HRC58-65; Chrome content:11-14% 4.Low chrome casting balls Size: 20mm-120mm Hardness:HRC45-55; Chrome content:1-3.5%