Heat Source
High Power Laser Beam
Material
Powder (Metal)
Transfer
Via Laser Beam
Process
Laser Hardening is a heat treatment process which uses a high power laser beam to locally harden the surface of steel or cast iron components. Being similar to induction hardening, laser hardening relies on the thermal mass of the component to quench the area to be treated. There is no need for quenching in water or oil to achieve the hardness you require.
Lasers tend to produce harder surfaces to a shallower depth compared to other hardening processes. This makes laser hardening ideal for improving the performance of intricate and high accuracy components.
Important considerations for laser hardening are:
Substrate Material
Only materials which undergo transformation hardening can be hardened by this method, carbon steels, high carbon stainless steels, cast irons and aluminium bronzes are typically considered hardenable.
Surface Finish
The absorption of the laser light into the substrate must be accurately controlled, the surface roughness and finish can dramatically influence the amount of laser energy which is reflected, therefore extremely reflective surfaces are very difficult to laser harden.
Depth of Hardness
Laser hardening can be used to produce a hardened layer up to 1.5 mm into the base material. In general, deeper hardening results in lower hardnesses.
Impact and Toughness
Laser hardening is capable of producing extremely hard microstructures sometimes over 1000 Hv, with this comes loss in ductility if your application demands high levels of toughness then perhaps laser cladding is a more suitable option.
General Features
- One major advantage of laser hardening is that it does not affect the surface finish of the component.
- This means laser hardening can be conducted on finish machined components, without the need to re-machine afterwards.
- Laser hardening can be completed with the same MET-CLAD Laser Cladding System used for cladding.
- The depth and magnitude of hardening can be varied, a depth of about 1.5 mm from the surface is quite normal
- Laser Hardening relies on the bulk of the component to rapidly draw heat away from the surface. Therefore any component must be of a sufficient size for the quenching process to be successful. As a guide the component should be at least 5 mm thick for optimum results.
- The surface finish and reflectivity of the component must be clean and consistent in order for the hardening depth and quality to be consistent. Generally a good machined or ground finish is acceptable.
Applications
Laser Hardening Systems can be used in a range of applications including, but not limited to:
- Automotive dies.
- Cast iron pistons.
- Chain-wheels.
- Cog-wheels.
- Crane wheels.
- Edges of blanking dies.
- Edges of pressing dies.
- Edges of cams.
- Edges of gears.
- Laser cladding.
- Plastic injection moulds.
- Sealer rollers.
- Steam turbine blades.
- Water pump components.
