2015 年 33 巻 2 号 p. 120s-124s
Residual stress, considered to be an influential factor in fatigue strength, was investigated through X-ray stress measurements on electron-beam welding joints, made of sheet metal with a thickness of approximately 10 mm. The Finite-Element Method (FEM) was also used to analyze the experimental results so as to verify any residual stress characteristics. The residual stress near the weld toe in the transverse direction was confirmed to be greatly compressed when the yield strength of the testing material became much greater. As a result of the three-point bending fatigue tests, except for S50C, it was demonstrated that the greater the residual stress of the test specimens was, the more they exhibited a longer fatigue life. It is thought that the reason for this was because the local area of the welded part became a stress concentration point due to its being greatly hardened.
