| 摘要 |
PROBLEM TO BE SOLVED: To provide a low yield ratio high tensile plate excellent in heat affected zone toughness.SOLUTION: A low yield ratio high tensile plate has a component composition containing, by mass%, C:0.003 to 0.025%, Si:0.01 to 0.07%, Mn:0.50 to 2.0%, P:0.008% or less, S:0.002% or less, Al:0.005 to 0.060%, Ti:0.025 to 0.080%, Nb:0.005% or less (including 0%), V:0.008% or less (including 0%), B:0.0025 to 0.0055%, N:0.0040 to 0.0080%, having a ratio of Ti amount and N amount, Ti/N of satisfying 4.0≤Ti/N≤12.0, containing one or two kinds of Mo:0.10 to 0.80% and W:0.10 to 1.20% with satisfying Mo+W/2≥0.30 and satisfying carbon equivalent Ceq of 0.33 to 0.63 and weld crack sensitivity index P:0.22 or less.SELECTED DRAWING: None |
