Forged grinding steel balls used in ball mill for mining industries: Diameter: 20mm, 25mm, 30mm, 40mm 50mm 60mm 70mm 80mm 90mm Hardness: HRC60-65(Surface and Volumetric) Characteristics: High hardness, good wear resistance, no breakage. We use the special high carbon steel materials to produce the mill balls to ensure the good performance of high hardness and wear resistance applicable in ball mills. For any interest or new enquiry, please don't hesitate to contact us.