Laser hardening, also known as laser surface heat treatment, is an advanced surface modification process designed to significantly improve wear resistance and extend component service life. It is widely applied to steel and cast-iron parts. During processing, a laser delivers precisely controlled, localized heating that rapidly elevates the material temperature above the austenitizing point but below the melting point. The surface then self-quenches through the thermal conductivity of the base material, rapidly cooling the heated layer and completing the hardening transformation.

This process produces a high-hardness, ultra-fine martensitic microstructure on the treated surface, greatly enhancing surface hardness and wear resistance. In addition, compressive residual stress is introduced at the surface, improving fatigue strength and long-term durability under cyclic loading.