The marageing steel and uses that marageing steel band which possesses high fatigue strength, production mannered null mass of the marageing steel which possesses high

摘要

PROBLEM TO BE SOLVED: To provide a maraging steel having high fatigue strength in which surface hardness is increased by reducing TiN being the starting point of fatigue fracture in a high cycle region and facilitating nitriding treatment, also, bending fatigue strength is improved by increasing the compressive residual stress of a surface nitrided layer, and old austenite crystal grains are refined for securing high strength and ductility, and which has satisfactory nitriding properties and weldability.;SOLUTION: The maraging steel having high fatigue strength has a composition comprising, by mass, ≤0.01% C, ≤0.1% Si, ≤0.1% Mn, ≤0.01% P, ≤0.005% S, 17.0 to 22.0% Ni, 0.1 to 3.0% Cr, 3.0 to 7.0% Mo, 7.0 to 20.0% Co, ≤0.1% Ti, 0.15 to 2.5% Al, ≤0.03% N, ≤0.005% O, ≤0.01% (not including zero) B, 8.0 to 15.0% Co/3+Mo+4Al, and the balance Fe with inevitable impurities.;COPYRIGHT: (C)2008,JPO&INPIT