The standard for structural-grade fasteners is the Din 933 Grade 8.8, characterized by medium carbon steel that meets the specifications of Bs 3692 Bolt Grade 8.8. Heat treatment involving quenching and tempering is applied to this medium carbon steel. Grade 8.8, being a medium carbon steel, is cold and tempered, offering high tensile strength, roughness, and toughness. https://www.shasanpiping.com/carbon-steel-8-8-fasteners-manufacturers-exporters-suppliers-stockists.html