Abstract: Provided is a method for producing alloy steel, the method comprising producing first alloy steel in a temperature holding furnace; maintaining the first alloy steel at a temperature of no lower than a melting point in the temperature holding furnace; and producing second alloy steel having an alloy content lower than the alloy content in the first alloy steel by melt mixing of the first alloy steel and molten steel. In the producing of the alloy steel, melting and storing of the ferroalloy are continuously performed, and thus, the temperature drop of the ferroalloy may be suppressed or prevented.

Abstract: Provided is a dephosphorizing flux configured to adjust a phosphorous component contained in molten steel, the dephosphorizing flux includes a main material including BaCO3 and a supplementary material, wherein the supplementary material includes a first material containing either of NaHCO3 or Na2CO3 and a second material containing CaF2. Thus, in accordance with a dephosphorizing flux and a method for preparing the same of the present disclosure, the plugging of a lower blowing nozzle that blows a carrier gas during dephosphorization may be prevented while improving a dephosphorization ratio. In addition, since environment polluting substances are not used as in conventional arts, environment pollution risk may be reduced, and the cost burden due to the facility for pollution prevention and harmful substance management may be alleviated.

Abstract: Provided is a method for producing steel including: preparing a first molten steel and a manganese-containing melt; supplying a nitrogen gas into a storage to blow nitrogen into the melt received in the storage and thereby adjusting a nitrogen content (wt %) in the melt to a required nitrogen content (wt %); and mixing the melt and the first molten steel to produce a second molten steel containing manganese and nitrogen. Since nitrogen is not blown while melting large amounts of solid materials, the oxidation of manganese due to a high temperature may be minimized or prevented. In addition, a large amount of solid material is not added, and a small amount of manganese-containing nonferrous metal or a FeMn ferroalloy is added, if necessary, into a produced melt in a molten state, and thus, a problem of temperature drop due to the input of the solid material may be minimized or prevented.

Abstract: Provided is a dephosphorizing flux configured to adjust a phosphorous component contained in molten steel, the dephosphorizing flux includes a main material including BaCO3 and a supplementary material, wherein the supplementary material includes a first material containing either of NaHCO3 or Na2CO3 and a second material containing CaF2. Thus, in accordance with a dephosphorizing flux and a method for preparing the same of the present disclosure, the plugging of a lower blowing nozzle that blows a carrier gas during dephosphorization may be prevented while improving a dephosphorization ratio. In addition, since environment polluting substances are not used as in conventional arts, environment pollution risk may be reduced, and the cost burden due to the facility for pollution prevention and harmful substance management may be alleviated.

Abstract: Provided is a method for producing alloy steel, the method comprising producing first alloy steel in a temperature holding furnace; maintaining the first alloy steel at a temperature of no lower than a melting point in the temperature holding furnace; and producing second alloy steel having an alloy content lower than the alloy content in the first alloy steel by melt mixing of the first alloy steel and molten steel. In the producing of the alloy steel, melting and storing of the ferroalloy are continuously performed, and thus, the temperature drop of the ferroalloy may be suppressed or prevented.