This sprocket is used for 20T excavator of KOMATSU , material is 50Mn or 45SIMN,the hardness is about HRC55-58,having wide choice range,the sprocket is applicable to special model of crawler type excavators and bulldozer from 0.8T-100T,it is widely applied in bulldozers and excavators of Komatsu,Caterpillar,Hitachi,Kobelco,Hyundai,Daewoo etc,adopts precision processing technology and special heat treatment technique,so reach the best wear-resistance and prolong life time to maximum extent.