12.9 grade of track bolt and nut,HRC38-42 8H7504---6S3419,4K7038---7K2017,7H3597---1M1408,7H3598---1S1860,7H3599---2S2140 We are professional manufacture of earthmoving fastener,all of our fastener are made by high grade alloy steel,the surface hardness can reach HRC36-42,tensile strength is 170,000 P.S.I. There are 10.9,12.9 class of track bolt and nut,plow bolt and nut,segment bolt with nut, ...