wear low,good toughness , broken less,high hardness metal ball widely used in cement building materials, metal mines, coal slurry ... to Japan, South Korea, USA, Australia, southeast Asian and African countries.specification:φ8, φ10, φ12,φ15,φ17,φ20,φ25,φ30,φ35 ... ,φ60,φ70,φ80,φ90,φ100surface hardness: low alloy of metal ball HRC≥45 high alloy of metal ...