The rolling contact fatigue of JIS SUJ2 (high carbon high strength bearing steel) heat treated by repeated quenching was
investigated. The microstructure of the bearing traces was observed before and after heat treatment by laser confocal
microscope and scanning electron microscope. X-ray diffraction was used to measure changes in the retained austenite
and the residual stresses on the bearing races' surface. The prior austenite-grain size was greatly reduced and the
compressive stress at the surface of the material was increased by the heat treatment. Both factors contribute to the
higher fatigue strength of the bearings.
The present paper will discuss the influence of the processing parameters on the characteristics of titanium models built by Selective Laser Melting. The microstructure and the fatigue strength of the three dimensional titanium models formed by Selective Laser Melting with an Nd-yttritrium-aluminum-garnet (YAG) pulsed laser are investigated. In order to increase the wear resistance of titanium models, surface alloying via laser-gas-nitriding (LGN) is applied. The mechanical properties of the models built by laser forming are adequate for fabrication of dental implants.