Improvement of the wear resistance of 316L stainless steel by laser surface alloying

In order to improve the sliding wear resistance of stainless steel components, carbide-hardened surfaces were produced on AISI 316L austenitic stainless steel by laser surface alloying. Different powdered precursors (Cr3C2, a mixture of Cr3C2 and Cr and a mixture of Ti and SiC) were applied to the steel surface and irradiated using a continuous wave, 300 W, Nd-YAG laser. The surface alloys resulting from the incorporation of Cr3C2 alone or mixed with chromium were composed of austenite (gamma) dendrites surrounded by a gamma-M(7)C(3) eutectic (M = Fe or Cr); their microhardness ranged from 380 to 450 HV. Superficial hardening by titanium carbide was obtained using a mixture of Ti and SiC powders as precursors; Ti and SiC particles dissolved in the melted pool, leading to the precipitation of fine TiC particles during solidification. The microhardness of the surface alloy was about 350 HV. For both chromium carbide and titanium carbide surface alloying treatments, the processing conditions were determined which led to a noticeable improvement of the sliding wear resistance of AISI 316L stainless steel without any detrimental effect on its high temperature oxidation resistance.