| 摘要 |
PROBLEM TO BE SOLVED: To provide a weld joint in which high toughness is ensured in each of a weld metal, a heat-affected zone and a bond part of a welded part with large heat input of a steel plate. SOLUTION: B is added in the steel plate with the welding heat input of≥200 kJ/cm and the plate thickness of≥30 mm so as not to adversely affect the toughness. B is sufficiently added in the weld metal part so as to suppress precipitation of a ferrite side plate generated from an austenitic grain boundary. B is added to the heat-affected zone so that the necessary minimum quantity of B to fix solid solution N generated by solid solution TiN is ensured by the diffusion of B from the weld metal part. COPYRIGHT: (C)2005,JPO&NCIPI
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