The goal of all hardening processes is a structural transformation of the steel. First, the ferritic material structure is austenitized by heating, and then transformed into hard martensite by quenching. Here, laser hardening has a decisive advantage, because it makes a selective heat input in predefined zones possible. By this, at complex components, a partial hardening can be realized while the higher flexibility of the ferrit structure can be kept in other zones as well. At induction hardening, this selective processing is not possible. Since the workpiece must always be heated only briefly, and it dissipates the heat over adjacent material layers, in most applications additional colling is nor required. As almost no warping of material is caused, there is often no need for additional methods to correct deformations of the workpiece.
Surface hardening with diode lasers
The techniques of surface hardening with lasers allow for the use of cost-effective materials and metals, also at components that are subjected to high mechanical stress. Hardening with laser means treating only the particular stressed areas of metals, e.g. at steels or cast iron in tool manufacturing. Thermal processing of large surfaces can be realized quite effectively and flexibly - e.g. at surface hardening in job order production - in combination with a Laserline OTZ zoom optic.
The process advantages of the diode lasers
With diode lasers, all demands for improved wear protection for machine components, tools, component parts and utilitarian objects are reliably met at hardening. The temperature regulation at hardening makes it possible to obtain optimal hardness for each material. But the laser heat treatment can also be used to reduce the firmness of high-strength materials to make sure higher degrees of deformation in these areas are possible.
Compared to other processes, a diode laser offers many advantages:
- Ideal adjustment of focus to the hardness contour
- Local heat treatment of defined partial areas
- Integration of hardening process into existing production lines
- Hardening of complex geometries possible