When a component made of steel or cast iron is hardened, the surface layer is austenitized for a short period of time. Subsequently, the heat introduced rapidly flows into the cold volume as the material cools. This self-quenching effect turns austenite into martensite. For thin-walled components, an external cooling medium may also be required. Up to a depth of about 1 mm, this phase transformation can be achieved. The martensite formation increases the hardness of the material, which improves the wear resistance of the component. The microstructure of the bulk volume remains unaffected, so that, for example, toughness and wear resistance can be optimally combined. In addition, the residual compressive stresses induced during martensite formation make it possible to improve the fatigue behavior of components subject to oscillation loads.