Available for both OD and ID applications, laser heat treatment can be used to harden the surface of heat-treatable steels. The laser heat treatment process is used both to improve wear resistance by increasing hardness, and to improve fatigue resistance by developing compressive residual stresses at the surface of components.
Laser heat treatment is a unique process in which the workpiece is heated very quickly (approximately 900oC/second) using a laser, then as the laser moves away, the part cools very rapidly without any external quenching media (i.e., no water or oil required).
Laser heat treatment is ideal for alloys like 4140 and 4330V. The hardened depth on these materials is typically 1 mm (0.040″) and can be as hard as 60 HRC for 4140. A significant compressive residual stress is also formed at the surface of hardened components, which can improve fatigue life, in particular for rotating components.
A feature that separates laser heat treatment from other surface-hardening methods is that only the area you need hardened is affected, not the entire part.