... the hardness 1.product introductionState-of-the art machiningEach roller shaft is engineered drop-forged and machined by ... frequency heat treating equipment guarantees maximum strength.Maximum lifeEach roller shell is carefully heat treated to ensure long wear ... impact low wear bimetal bushings. Replacement parts of track roller for Caterpillar,Komatsu,Hitachi,Kobelco,Mitsubishi,Sumitomo,Daewoo,Hyundai ...