... other friction-link project. I bolt steel companies choosing the material quality, production, advanced technology, reliable quality, low price ... hitachi, kobelco, daewoo, kato, hyundai, samsung, sumitomo, mitsubishi, etc.Specifications Size from: M5 - M42 Length: 10mm-200mm Hexagon head bolt ... : GB/T 1228-1231,ASTM A325 A490 A325M A490M1- Raw material : 40Cr,35Crmo2-Surface hardness: HRC:34-38,38-42 ...