Medial Chrome Cast Grinding Ball with the high quality and the best price. Specifications:1) Diameter: 12~ 120mm2) Low breakage and low wear rate3) Hardness: 50HRC min.4) Applied areas: cement building materials, metal mining, coal pastethermal power plants, chemical engineering, ceramic coating, lightindustry, magnetic materials 5) Microstructure:P+C6) Chemical composition (%):a) C: 2.0 - 3.3 b) Si: 1.2 max.c) Mn: 1.2 max. d) Cr: 4.0 - 9.0e) P: 0.10 max.f) S: 0.10 max.packing: ton bag or steel drum