Heat Treating and Surface Modification

Heating is conventionally induced by a furnace, flame, arc or induction coil. In contrast, the Laser beam is focused or shaped into a suitable pattern and scanned over the component.

The high energy density Laser beam heats the surface much more rapidly, reducing the time for conduction into the bulk of the component. The advantages of Laser surfacing (compared to alternative processes) are:

• Chemical cleanliness and cosmetic appearance
• Minimal heat input, reducing distortion and creating a very small heat-affected zone.
• No post machining required
• Non-contact process
• Ease of integration.

The range of alloys that can be transformation hardened by Laser techniques covers all those than can be hardened by conventional methods. The response of steel to hardening increases with increasing carbon content, and hardness values have exceeded 700HV for steels containing 0.75% carbon content.  In addition because of the high cooling rates plain carbon steel (0.2%C) will harden.

The hardenability of cast irons is controlled by the amount of pearlite present, and only martensitic stainless steels will respond to heat-treating.

The automotive industry is responsible for much of the Laser heat-treatment process development.

Applications include: