Method for controlling sulfur in 70-grade tire cord steel smelting under large scrap ratio

The invention discloses a method for controlling sulfur in 70-grade tire cord steel smelting under a large scrap ratio. The method for controlling sulfur in 70-grade tire cord steel smelting under the large scrap ratio comprises the steps of desulfurizing molten iron; smelting in a converter; performing LF refining; and normally carrying out subsequent procedures. According to the method for controlling sulfur in 70-grade tire cord steel smelting under the large scrap ratio, graphite carbon balls are added in the smelting process, the tapping temperature is controlled, the mode of changing the alkalinity of the refining slag is adopted in the refining process, and the like, so that when 70-grade tire cord steel is smelted through the converter with the large scrap steel ratio being 25% or above, the requirement that the scrap steel ratio is 25% or above can be met, the sulfur content in the final molten steel after smelting can be controlled to be 0.006% or below, and the requirement of a user on the strand b