FATIGUE RESISTANT WELDED JOINT AND ITS WELDING METHOD

PROBLEM TO BE SOLVED: To provide a welded joint which is improved in fatigue resistance by making the residual stress of a weld zone into compressive residual stress, and its welding method, by solving the problems that the tensile residual stress is caused in the weld zone by the shrinkage accompanying cooling in the conventional welding technique at the time of welding and repairing of a steel structure and the stress concentration at the toe of the weld is superposed thereon, a fatigue crack is easily caused, and the fatigue strength of the weld zone is remarkably degraded. SOLUTION: Face welding is performed under welding conditions under which a weld metal is made martensite and a bead width is made 50 to 90% of the original weld bead width by using any of coated arc welding rod, filler wire or flux cored wire where the carbon content of the weld metal in the longitudinal direction at the center of width of the weld bead of a butt, fillet, etc., becomes >0.5% and ≤1.0%, by mass%, and the compressive residual stress is imparted to the weld toe part and the fatigue resistance is improved. COPYRIGHT: (C)2005,JPO&NCIPI