... prepared.chemical elements.high chrome casting steel ball:c:2.0-2.8,si:<1.0,mn:0.5-1.5,cr:22 ... -30,mo:0-1.0,cu:0-2.0,ni:0 ... ,s<0.06middle chrome casting steel ball:c:2.1-3.2,si:0.5-2.2,mn:0.5-1.5,cr:7-15 ... .10,s<0.06low chrome casting steel ball:c:2.2-3.6,si:<1.2,mn:0.5-1.5,cr:1.5 ...