... ) A variety of automotive ,motocycle parts , high frequency quenching ,heat treatment , such as: crankshaft, connecting rod, piston ... rocker, rocker shaft and other high-frequency quenching.2) High-frequency quenching hardware tools such as pliers, hammer, ... deeper hardening layer : about 5mm High frequency induction quenching equipment : hardening layer is less than 1mm Supersonic frequency induction ...