SELECTIVE-AREA CARBURIZING OF LOW-CARBON STEEL USING AN ND-YAG LASER

Selective area laser carburizing of low carbon steel can be performed faster and without any precarburizing treatment. The added advantage of laser carburizing is rapid cooling, which leads to a fine microstructure and high hardness. AISI 1018 steel was selectively carburized using a 400 watt Nd:YAG laser. A maximum hardness of about 1050 Hv was obtained in laser carburized samples, which is comparatively higher than that obtained by conventional carburizing techniques. A wide range of microstructures were achieved under different processing conditions of laser carburizing. The most desirable microstructure was found to be a mixture of eutectic (alpha(Fe) + Fe3C) and austenite. Such composite microstructure is ideal for wear-resistant coating, comprising a hard phase (eutectic) and a soft phase (austenite).