gear 1,material:STEEL(A3/45) 2,industrial gear got ISO 3,8 year sprocket and gear ... transmission sprocket:100B-1-15T,material: C45/A3, surface: chroming, heat treatment, standard: ISO,ANSINo.2 Machinery transmission sprocket:16A-18T, material ... :C45/A3, surface: heat treatment, standard: ISO, ANSINo.3 ...