Until with the steel sheet for hull construction under full house thermal match

摘要

PROBLEM TO BE SOLVED: To form a welded joint having sufficiently high fracture toughness Kc by butt-welding a high strength ship steel plate whose yield strength is 460 Mpa class and whose thickness is 50 mm.;SOLUTION: In the large heat input butt welding joint being a structure obtained by butt-welding high strength steel plates having a thickness of ≤50 mm, it is defined that: (a) the hardness of weld metal is ≥70% and ≤110% of the hardness of the base material; (b) the width of the weld metal is ≤70% of the plate thickness of the base material; (c) the width of a weld heat-affected zone is ≥5 mm which is softened to the hardness of ≤95% of that of the base material unaffected by heat if necessary; and/or (d) the original austenitic grain size is ≤200 μm in the weld heat-affected zone in contact with a fusion weld line.;COPYRIGHT: (C)2005,JPO&NCIPI