Pulsed power discharge for producing an ultra-thin hardened layer

The hardening of steel involves a combination of heating above the austenit izing temperature followed by rapid cooling to achieve martensite. Some met hods of surface: hardening, like laser or inductive hardening provide harde ned layer thicknesses in range of 0.3-1.0 mm. The production of an ultra-th in hardened layer, under 50 mu m, on the steel surface is described. The te chnology of hardening is based on a pulsed heating of the steel surface due to the light emission of a pulsed power are and a subsequent cooling due t o dissipation of heat into the underlying steel substrate. The duration and power of heating define the thickness of a hardened layer to a great degre e. The thickness of a layer can be varied from tens to hundreds of microns. The structure of steel underneath the hardened layer remains unchanged. It is possible to harden the surface of a steel work-piece that is prone to m echanical deformations like a spring or thin blade. The hardened layer can be elastically deformed because it is extremely thin. The work-piece retain s its spring properties while the surface is independently hardened. The pr ocess can be applied to an uneven surface. The experimental data and simula tions presented are in good agreement.