When laser-hardening â€“ also referred to as marginalized layer hardening â€“ the laser beam with its adjustable focal spot size is guided over the welded surfaces by a robot. The energy of the laser is applied directly to the workpiece surface. This marginalized layer is then heated in a very short period of time and locally limited to the required hardening temperature. The integrated temperature measurement in the beam geometry ensures that the heat input is uniform. The laser beam's interaction time with the surface determines the hardness penetration depth.
The advantages of laser hardening can be summarized as follows:
- Zones that are subject to wear can be hardened in a contour-accurate and precise way.
- Hard marginal zone, tough core
- Rapid cooling through self-quenching
- No cooling media required
- Less or no re-work due to the formation of the hardening path by means of shielding gas.
- Hardening paths are possible on cutting edges, guide ways, grooves, and
free-form surfaces with continuous geometric transitions.
- Hardening is possible in atmospheric conditions without the use of shielding gas.