Laser heat treatment, abbreviated as LHT, is also known as laser quenching or laser phase transformation hardening. It is a surface heat treatment method that uses a high-energy laser beam to rapidly scan a workpiece, causing the surface temperature of the irradiated metal or alloy to rise above the phase transition point at an extremely fast speed. When the laser beam leaves the irradiated area, due to thermal conduction, the cold matrix is rapidly cooled and self quenched to obtain a finer hardened layer structure