... high tensile fastener,all of our bolt and nut made by 40Cr or 35CrMo,hardness HRC38-42 We have 8.8,10.9,12.9 ... grade of track bolt and nut,plow bolt and nut,segment bolt and nut.Besides the OEM parts ... .8 120,000PSI HRC28-34Grade 10.9 150,000PSI HRC34-38Grade 12.9 170,000PSI HRC38-42Track bolt and nut,from diameter 7/16 ...