... ,the surface hardness can reach HRC36-42,tensile strength is 170,000 P.S.I. There are 10.9,12.9 ... reply you as soon as possible. 8S03958S17239S18387T09987T09997T22836V17246V17256V17276V1728 12.9 or 170 grade of Plow Bolt, Track Bolt and Segment Bolt