Abstract
The aim of the present study was to clarify the residual stress of TiC coated steels by the X-ray diffraction measurements and to make clear the effect of TiC coating on fatigue strength. TiC layers were coated on three kinds of steels by a chemical vapor deposition method (CVD) under several coating conditions. Fatigue tests were conducted by using the plain specimens (flat plate type) and stress concentration type specimens (cantilever flat plate type). As the results, it was confirmed that a large compressive stress was observed in the CVD layer of TiC, whereas tensile stress or smaller compressive stress occurred in the substrate region adjacent to the interface. It was also found that the fatigue strength of TiC coated steels become lower than that of the specimens without TiC coating, but the quenching and tempering treatment after TiC coating improved the fatigue strength. It was concluded that the hardness of substrate and the residual stress in the top part of substrate and the TiC layer were the main factors affecting fatigue strength of TiC coated steels.
