鋼材の脆性亀裂伝播特性におよぼす低サイクル疲労の影響

概要

論文の詳細を見る
The effect of low cycle fatigue on the propagation characteristics of brittle crack in steels has been studied by means of the double tension test. The specimens used were the mild steel for hull structure (i. e. the semi-killed steel) and the ferritic high notch toughness steel (i. e. the Al-killed steel pressed, acceleratedly cooled and tempered), both of which were cumulated with low cycle fatigue previous to the double tension test.As a result of the study, it has been clarified that the arrest-transition temperature of brittle crack is raised with the cumulation of low cycle fatigue. More details obtained are as follows ;1. There is no clear correlation observed between the increase of the arrest-transition temperature of brittle crack and the variations in the alternate stress of low cycle fatigue as well as in the cumulation number of that.2. In case of the mild steel for hull structure, the arrest-transition temperature of brittle crack is raised with increase in the cumulated plastic strain below about 25 percent although it is kept nearly constant for the plastic strain above that critical value.