WELDED STRUCTURE OF STEEL STRUCTURE AND METHOD FOR WELDING STEEL STRUCTURE

摘要

PROBLEM TO BE SOLVED: To prevent the weld crack of root or plural layers without preheat management by forming the root or plural layers on the root side of the welded joint of the single bevel groove of a steel structure of a weld metal which is lower in strength and higher in ductility than a base metal and forming the remaining layers of a weld metal having the strength equivalent to or higher than the strength of the base metal. SOLUTION: A steel beam 3 is joined by welding to a steel column 2. The root or plural layers 1a on the root side of the welded joint of the single bevel groove 1 formed at the end of the flange part 3a of the steel beam 3 are formed of the weld metal which is lower in strength and higher in ductility than the base metal of the steel column 2 and the steel beam 3, etc. All of the remaining layers 1b are formed of the weld metal having the strength equivalent to or higher than the strength of the base metal. A backing strip 4 is used for welding. The root or plural layers 1a on the root side are welded by a MAG welding method or MIG welding method and all of the remaining layers 1b are welded by either of the MAG welding or the MIG welding method or TIG welding method. As a result, the stress concentration of the stress concentrated part is relieved and the brittle fracture against external force is prevented.