Abstract
High fatigue strength is required for maraging steel applied for the CVT belt, and three methods are applied to improve fatigue strength of maraging steel as follows; selecting alloy with high tensile strength, adding high residual stress of compression at the surface of material by nitriding, and refining TiN type non-metallic inclusion existing in the alloy matrix. Control of TiN size by optimizing the condition of melting process has been conducted in our company and the quality of our strip-shaped products is stable now. Currently higher fatigue strength of maraging steel for CVT belt are required and our approach of improving the fatigue strength by modification of alloy compositions of maraging steel are also presented.
Keywords: maraging steel, fatigue strength, CVT belt, nitriding, alloy compositions