| 摘要 |
<p>PURPOSE: A method for manufacturing a steel sheet for a marine lifesaving structure with a superior CTOD(Crack Tip Opening Displacement) property on a weld heat-affected zone is provided to improve the tensile property of the welded part by lowering the carbon content and restricting the formation of high carbon martensite. CONSTITUTION: A method for manufacturing a steel sheet for a marine lifesaving structure with a superior CTOD property on a weld heat-affected zone comprises the steps of: heating a slab at 1000~1200°C, finish-rolling the slab at 700~900°C and accumulated reduction amount 30%, and cooling the rolled slab to a cooling stop temperature of 300~650°C at the cooling rate of 2~40°C/s. The slab is composed of C 0.02~0.07 weight%, Si 0.2 weight% or less, Mn 1.2~1.7 weight%, P 0.012 weight% or less, S 0.003 weight% or less, Al 0.005~0.02 weight%, Cu 0.1~0.5 weight%, Ni 0.1~1.0 weight%, Ti 0.007~0.013 weight%, N 0.002~0.006 weight%, and the rest Fe and other inevitable impurities.</p> |
