Steel sheet with excellent toughness of weld heat affected zone in super large heat input welding

摘要

A steel plate having a heat-affected zone(HAZ) with excellent toughness in ultra high input heat welding is provided to secure excellent HAZ toughness even when heat input welding of more than 60KJ/mm is performed. A steel plate having a heat-affected zone with excellent toughness in ultra high input welding comprises 0.03-0.10 mass% of carbon, less than 0.5 mass% of silicon(including 0%), 1.0-2.0 mass% of manganese, less than 0.015 mass% of phosphorus(excluding 0%), less than 0.0010 mass%(excluding 0%) of sulfur, 0.005-0.060 mass% of aluminum, 0.008-0.030 mass% of titanium, 0.0050-0.010 mass% of nitrogen, 0.0015-0.0035 mass% of calcium and less than 0.0015%(excluding 0%) of oxygen.