The so-called hardening of Hexagon Socket Head Bolt refers to the hardening of the Hexagon Socket Head Bolt required by customers. Hardening is what we often call heat treatment, which refers to heat treatment of Hexagon Socket Head Bolt. Hardening of Hexagon Socket Head Bolt is also called quenching. Quenching can increase the hardness of Hexagon Socket Head Bolt, but Hexagon Socket Head Bolt needs toughness High tensile strength is required, but high hardness is not required. Therefore, in general, Hexagon Socket Head Bolt needs to be quenched + high temperature tempering-also called quenching and tempering treatment, to enhance the tensile strength of Hexagon Socket Head Bolt. The simple understanding of China Fasteners Suppliers is to harden the Hexagon Socket Head Bolt to increase the hardness of the Hexagon Socket Head Bolt.