METHOD FOR CONTROLLING THE CARBON CONTENT OF MOLTEN-STEEL IN THE MANUFACTURE OF BAKE HARDENED STEEL

PURPOSE: A molten steel carbon component control method in manufacturing bake hardening steel is provided to effectively perform the control of carbon component in molten steel which is completed with decarburization treatment in a constant range, thereby securing the reproducibility of the carbon concentration in the molten steel. CONSTITUTION: A molten steel carbon component control method in manufacturing bake hardening steel comprises the following steps of: treating molten steel vacuum degassing to reduce the carbon concentration(S1); injecting slag deoxidizer into a slag layer formed on the upper end of the molten steel upper to control the carbon concentration in the molten steel to be within a standard range(S2); and the carbon in the slag layer is flowed into the molten steel while the slag layer is deoxidized(S3). [Reference numerals] (AA) Start; (BB) End; (S1) Step of reducing the concentration of carbon in molten steel; (S2) Step of injecting a slag deoxidizer into a slag layer; (S3) Step of allowing carbon in the slag layer to flow into the molten steel;