Hardening

Homogeneous heat treatment - suitable for all component geometries - high efficiency

The process

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

Application examples

Surface hardening

Hardening with a laser means treating only the especially stressed areas of metals, e.g. at steels or cast iron in tool manufacturing.

The beam structure is only heated and changed in the near-surface areas of a workpiece - the so-called surface layers. As the diode laser beam can be directed selectively and flexibly onto the workpiece from just about any directions and the temperature can be controlled precisely on the workpiece, the surface hardening of geometrically, highly complex components becomes possible. From gearwheels and sprocket wheels over cam and worm shafts to gripping and cutting tools in rope drums, almost every surface geometry can be successfully hardened with Laserline’s diode lasers.

Hardening of camshafts

The shafts are mainly used in the automotive section. The complex geometry of camshafts and their extreme material stress utilization scenario demand a targeted and selective hardening, where only the beam structure of surface layers is hardened. In subjacent material layers, flexible structures must remain so that the permanently rotating shaft does not become brittle or rigid in a hasty manner.

Source: Matex PM

Job order hardening

Production companies rely on job order hardening, for buying their own hardening equipment is not worth it from different reasons. These companies operate in different areas, such that hardening agents have to handle various requirement demands. Laserline's diode lasers are an excellent tool because of the possibility for flexible beam guidance and the precise temperature in which they can treat almost any workpiece successfully. When it comes to buying, they are the cheapest among all available beam sources. Furthermore, they have outstanding efficiency during operation because of their high energy efficiency, long lifetime, and low maintenance costs. 

MATEX PM, a company from Pilsen in the Czech Republic, offers job-shop solutions for different metal applications with the diode laser. Together with Laserline, MATEX PM searched for a way to protect a rope drum out of cast iron (with a diameter of two meters and a weight of 2.5 tons) from too high wear when in use.