media ball,grinding steel ball,Forged steel balls,steel ball,grinding ball,grinding media,mill ball Diameter:20mm150mm Hardness: HRC5565 chrome casting iron balls,casting iron ball,casting steel ball,chrome steel ball,chrome ball Diameter:17mm120mm Cr content:1014% Hardness:HRC5663 Features: High and steady hardness,no breakage,good wear resistance and .