METHOD FOR CASTING WEATHERABLE COLD ROLLED STEEL

摘要

PURPOSE: A method for casting weatherable cold rolled steel is provided in which the weatherable steel can be thinned by lowering the surface defects in the state of steel billet of the weatherable steel which is used as a material of a heat exchanger or an industrial boiler. CONSTITUTION: The method for casting weatherable cold rolled steel comprises the steps of controlling an overheating degree in a tundish of molten steel consisting of 0.06 to 0.08 wt.% of C, 0.90 to 1.0 wt.% of Mn, 0.17 to 0.24 wt.% of Si, 0.02 wt.% or less of P, 0.01 wt.% or less of S, 0.2 to 0.3 wt.% of Cu, 0.2 to 0.3 wt.% of Ni and a balance of Fe and other inevitable impurities to a temperature of 17 to 23 deg.C; casting in a casting speed of 1.12 to 1.17 m/min by injecting the molten steel into a mold a taper of which is set to 1.00 to 1.05; and cooling the steel billet transferred passing through the mold to a water-liter steel-ton of 0.29 to 0.35 l/kg at a second cooling zone.