パルス中性子応力測定法による超音波衝撃処理した十字溶接継手の残留応力評価

鈴木 環輝*; 大川 鉄平*; Harjo, S.; 佐々木 敏彦*

日本機械学会論文集(インターネット), 87(894), p.20-00377_1 - 20-00377_15, 2021/02

https://doi.org/10.1299/transjsme.20-00377

The residual stress state inside the cruciform welded joints were measured using the pulsed neutron stress measurement method. The points of interest in this study are the weld toe and its interior. We also compared the cases with and without ultrasonic impact treatment (UIT), which is expected as a fatigue strength improvement technology. Furthermore, the case where tensile stress or compressive stress was applied after UIT treatment was also examined. The applied stresses at this time were 75% or 85% of the yield point, respectively. From the above, we considered the cause of the change in the residual stress on the surface after UIT treatment, which was clarified in the preliminary experiment, in the early stage of fatigue. As a result, the load after the UIT treatment caused plastic deformation in a part of the inside, which caused the redistribution of residual stress.