き裂状表面欠陥を有するステンレス鋼溶接継手の疲労限度改善と欠陥の無害化

－レーザピーニングの効果－

抄録

The effects of laser peening (LP) on the bending fatigue limit of an austenitic stainless steel JIS-SUS316 welded joint containing an artificial semi-circular slit on the weld toe were investigated. Three-point bending fatigue tests were carried out at a stress ratio of R = 0.05 for both LP treated welded specimens with the slit on the weld toe and those without the slit. The fatigue limits of all specimens increased by 23-64% due to LP. LP treated specimens with a slit depth of a = 0.2 mm had high fatigue limits that were nearly equal to those of non-slit, LP treated specimens. Therefore, a semi-circular slit of less than a = 0.2 mm could be rendered harmless due to LP. The improvement of fatigue limit due to LP was mainly achieved by compressive residual stress.