Fatigue Strength of Radical Nitrided Spheroidal Graphite Cast Iron

Abstract:

In order to investigate the effect of radical nitriding on fatigue strength of spheroidal graphite cast iron FCD400, rotating bending fatigue tests were carried out at room temperature. Fatigue strength was increased by nitriding. Fracture started from microshrinkages or abnormal graphites in the same manner as that of as cast iron. However, fracture mode was different according to the stress level. That is, fracture occurred from specimen surface at high stress levels and it occurred from defects in subsurface at low stress levels. The cause of these results was the hardened layer and the compressive residual stress, which suppressed the initiation of the surface crack.

• Periodical: Key Engineering Materials (Volumes 488-489)
• Pages: 238-241
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.488-489.238
• Online since: September 2011
• Authors: Kazuhiro Morino, Fumihito Nishimura, Norio Kawagoishi
• Keywords: Fatigue, Fracture Mode, Fracture Origin, Nitriding, Spheroidal Graphite Cast Iron

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