Abstract
In order to investigate the suitable nitriding condition on fatigue strength of maraging steel, rotating bending fatigue tests were carried out for steels nitrided at 480℃ for 0.5,1 and 5h. The fatigue strength was increased due to nitriding. The increase in fatigue strength and the fracture mechanism were markedly influenced by nitriding time. That is, fracturing of the specimens nitrided for 1h and 5h occurred from the specimen surface in the short life region, and from the interior in the long life region, although all of the specimens nitrided for 0.5h fractured from the surface similar to the aged specimens. Consequently, S-N curves in the former specimens showed a two-step shape. The suitable nitriding time was around 1h at the same nitriding temperature of 480℃.
