Method for producing 45# large flat steel ingot by electric furnace

The invention discloses a method for producing 45# large flat steel ingot through an electric furnace, and the flat steel ingot has the weight of 30 to 50 tons. The method comprises the steps of EAF furnace primary smelting furnace steel and iron material batching, tapping conditions, tapping material adding control, LF furnace refining recarburization and slagging deoxidation inclusion removal, vacuum treatment and die casting pouring temperature control. The method concretely comprises the steps of EAF furnace primary smelting furnace steel and iron material batching molten iron control, thecontrol of the carbon content of the molten steel during tapping, the use of carburant in LF furnace refining and the adding of a proper amount of slag and a deoxidizing agent, the forming of white slag and the keeping for enough time, the control of vacuum holding time and argon flow in different stages in VD furnace vacuum treatment, and the control of temperature in die casting pouring. According to the 45# steel prod