Laser hardening – the method
The goal of all metal hardening processes is to ensure a structural transformation of steel and cast iron materials with greater strength. First, the original ferritic-perlitic material structure is austenitized by heating, and then transformed into hard martensite by quenching. Here, hardening with high-power diode lasers has the decisive advantage of making an exclusive locally heat input at stressed areas possible. By this, at complex components, a partial hardening can be realized, while in other zones the ductility of the initial structure can be maintained. With induction hardening, such a local treatment is not possible in many cases. As the workpiece is only heated near the surface at laser brazing and the heat is discharged very efficiently over the neighboring material, in most cases there is no need for an additional quenching media. As the warpage is compared to other hardening techniques in quite a minimal way, additional methods to correct the material deformations can mostly be omitted.
Surface hardening with diode lasers
The processes of surface hardening with laser are generally usable for all materials at which classical hardening methods can be used due to the adequate carbon content. At laser hardening, only the especially stressed areas of the components are locally hardened, e.g. at steels and cast iron in tool manufacturing. The thermal treatment of wear or cyclical stressed component areas – e.g. in job order production – can be realized quite effectively and flexibly in combination with a Laserline OTZ Zoom optic.
Process advantages of the diode harden laser
Hardening with diode lasers makes it possible to achieve the respective material-specific maximum hardness at machine components, tools, component parts, and commodities. The temperature regulation during the metal hardening process ensures that the respective optimal process results for each material and application are reached. However, laser heat treatment can also be used to locally reduce the firmness of high-strength materials to make sure better deformability in those local areas.
Compared to other processes, a diode laser offers many advantages:
Ideal adjustment of the focus to the hardness contour
- Local heat treatment of defined partial areas
- Integration of the heating process in existing production lines
- Hardening of complex geometries is made possible