Laser surface alloying of nickel and chromium (III) electroplated carbon steel with Nd: YAG laser

Abstract

Laser surface alloying is one of the post treatment techniques developed to enhance the surface properties of electroplated steels. In this investigation, AISI 1020 carbon steel was selected as the base material. The base material was electrodeposited by nickel followed by trivalent chromium. The thickness of the Ni and Cr layers were approximately 30μm each. The surface of the chromium (III) was melted using 2kW Nd: YAG laser. The laser surface alloying was carried out at different energy densities by keeping laser power at 500W and 650W, at different scanning speeds i.e. 2, 1.5, 1, 0.75, 0.5 m/min and at two different optics arrangements. The energy density was varied from 12×106 J/m2 to 61×106 J/m2. The laser surface alloyed samples were examined by Optical Microcopy, Vickers Microhardness tester and Energy Dispersive spectroscopy. It was observed that the laser melted depths varied from 200-800μm based on the energy density.