... 30 # 9 # 400-800 Shape: spherical Weight: 2.5g/m3 Bulk density: about 1.5g/cm3 Mohs ... the inert chemical activity of silica without interference concerns; 2, circular elastic particles, impact resistance, can be recycled many ... the fatigue strength, and to reduce friction and wear; 2, sand-blasting, paint, in addition to carbon, ... 70-150 GB 180 # 3 # 70-110 GB 220 # 2 # 50-100 GB 280 # 1 # 40-70 GB 320 ...