... material 3 Good quality and serviec 4 Competitive price Steel Balls specification1 Available in Different Sizes and Grade: From 1mm ... SS430) and ceramic balls( Si3N4, ZirO, SiC, glass, POM, PTFE, PP)3 Widely used for bicycles, motocycles, grinding and other fields4 ... 0.035 max Cr: 0.28-0.603.High chrome cast grinding ballSize: 20mm-150mmHardness: HRC 58-65 chrome content 12- ... .5-1.5 S&P≤0.15 Steel Balls