These forgefix high tensile hex head bolts are made from 88 grade steel the bolts are part threaded and conform to din 933 standards the hexagonal head has been designed for use with spanners or sockets and offers maximum torque when used with these tools applicationfor fastening together numerous types of material or to be fastened into pre tapped holes widely used in many engineering applications zinc coatings prevent oxidation of the protected metal to create a longer lasting finish it does t