... 2.hardness:HRC55-HRC60 3.model:Hitachi,Komatsu,Caterpillar,Kobelco&Hyundai 4.history:more than 15 years Hitachi,Komatsu ... ,Caterpillar,Kobelco excavator parts,excavator mater pins and bushings1.raw ... material:40Cr2.hardness:HRC55-HRC603.model:Hitachi,Komatsu,Caterpillar,Kobelco,Hyundai4.technology:forging+thermal treatment&fine grinding+coarse grinding5 ...