OS0826 応力集中部にき裂を有する高強度鋼のショットピーニングによる疲労限度向上およびき裂の無害化

抄録

Effect of shot peening on the fatigue limit of high tensile strength steel containing a crack on stress concentration zone was investigated. A pre-crack was introduced, subsequently shot peening was introduced. And the bending fatigue tests were carried out. Obtained results were as followings; (1) the fatigue limit of specimens containing a crack of 0.2 and 0.3mm in depth are improved up to around two times value. (2) In case of shot-peened specimens with a crack of 0.2 mm in depth, fracture occurred from outside the pre-crack moreover they recovered the fatigue limits up to that of specimens with no crack. (3) A safety crack size of shot-peened specimen could be estimated by calculation of stress intensity factor of pre-crack.