WELDED JOINT AND WELDED STRUCTURE HAVING EXCELLENT BRITTLE CRACK PROPAGATION RESISTANCE

摘要

A steel plate welded joint (1) formed by butt-welding steel plates (2, 2) in which brittle crack arresting properties (Kca) of at least a part of the area of a base metal are 4000 N/mm1.5 or more, and a welded structure (A) including the welded joint, wherein a brittle crack propagation resistance direction control unit (3) is provided to at least one place of the steel plate welded joint; wherein the brittle crack propagation resistance direction control unit has a projection (4) formed on one of the steel plates, and an inclination bead (31) between the projection and the other thereof; and wherein the inclination bead extends from a weld line (L) of the steel plate welded joint, is inclined at an angle in a range of 15°-50°inclusive relative to the longitudinal direction of the steel plate welded joint, and is formed so as to face the area in which the Kca of the steel plates is 4000 N/mm1.5 or more. As a result, even if brittle cracks occur in the welded joint, the brittle cracks can be prevented from propagating through the welded joint or the base metal.