Author(s)

K. Fukada, K. Kawagoishi, K. Morino & H. Nisitani

Abstract

Influence of Radical Nitriding on Fatigue Strength of Maraging Steel K. Fukada*, K. KawagoishT K. Morino^ & H. NisitanT* ' Kohan Kogyo Co., Ltd. a L^zverszfy, Abstract Rotating bending fatigue tests were carried out to investigate the influence of radical nitriding on surface integrity and fatigue strength for a maraging steel. Fatigue strength was increased by nitriding. The initiation site of fracture was the surface at high stress levels and the interior at low stress levels in a nitrided steel, though it was the surface at all the stress levels in an aged steel. Consequently, S-N curve of the nitrided steel showed a double staged one, though that of the aged steel was an ordinary S-N one. In the nitrided steel, the main reason for the suface fracture was surface embrittlement while the one for the interior fracture was surface hardening, due to nitriding. 1 Introduction Maraging steel has both high static strength and ductility. The fatigue stren

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