著者
酒井 久裕 落合 鍾一 上野 學
出版者
一般社団法人 日本鉄鋼協会
雑誌
鉄と鋼 (ISSN:00211575)
巻号頁・発行日
vol.75, no.4, pp.657-664, 1989-04-01 (Released:2009-06-19)
参考文献数
22
被引用文献数
2

The purpose of this work is to present results on the mechanical properties of SUJ 2 bearing steel improved by a cyclic heat treatment. The structure of thermally cycled steel consists of fine-grained ferrite particles of the size under about 2 μm containing fine cementite particles of the size about 0.2μm. Thermally cycled steel was found to be superplastic at 710°C, just below A1 temperature, at an initial strain rate of 1.67 × 10 -4s -1, i.e. elongation to failure was about 500% and the strain rate sensitivity, m value, was about 0.4. The activation energy of about 180 kJ/mol, which is nearly equal to that of grain boundary diffusion of Fe atoms in α-iron, was obtained for this plastic deformation. Furthermore the rolling contact fatigue life test was performed at room temperature under constant load. The fatigue life of SUJ 2 steel thermally cycled was found to be prolonged (about 2.5 times) as compared with that of conventional one.