Production control method for ultra-low limit sulfur in low-carbon low-phosphorus clean steel

Abstract

The invention provides a production control method for ultra-low limit sulfur in low-carbon low-phosphorus clean steel, and belongs to the technical field of metallurgical steelmaking. The method comprises the steps that molten iron pretreatment is specifically used for providing low-sulfur molten iron for a converter; low-temperature mid-term process deslagging in the early stage of the double-blown converter is carried out to achieve low-phosphorus control of the converter; middle and later period secondary slagging of the double-blown converter, the last phase post stirring function and high temperature tapping are carried out, so that high temperature, low carbon and low sulfur and phosphorus tapping of the converter are achieved; an argon blowing station is used for ladle pre-slaggingto create favorable conditions for rapid deep desulfurization of LF refining and inhabitation of recarburization and nitrogen increase; LF refining is used for achieving accurate deep desulfurization; and VD vacuum degassing and slag washing methods are used for achieving the functions of denitrification, dehydrogenation, removal of inclusions and stable desulfurization so as to finally achieve the goal. According to the method, a key control interface of smelting is formulated according to the process route, key tasks of all processes are clarified, relationships of mutual promotion and mutual restriction between all processes are coordinated, and finally, the sulfur content in the steel is controlled to be less than 0.005%.

Description

technical field [0001] The invention relates to the technical field of metallurgy and steelmaking, in particular to a method for controlling the production of ultra-low limit sulfur in low-carbon and low-phosphorus clean steel. Background technique [0002] [S] and [P] are easy segregation elements in steel, among which [S] is easy to form plastic inclusions with Al, Ti, Mn, Cu, etc., which seriously endangers the comprehensive process mechanical properties of steel materials; [P] thermal In the cold state, it will reduce the high temperature strength of the slab, and in the cold state, it is easy to cause the "cold brittle" phenomenon of the steel material, which deteriorates the low temperature toughness index of the material; at the same time, [S] and [P] are also an important factor for cracks in the steelmaking slab , so [S] and [P] are generally regarded as harmful elements in the smelting process of some high-grade steel grades, and the lower the expectation, the bett...

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Problems solved by technology

Moreover, this kind of technological process has complex procedures in the actual operation process, requires multiple liftings, logistics is difficult to achieve, and furnace matching is difficult; at the same time, there are many procedures, which means that the process temperature loss is high, and a large increase in LF refining is required. The temperature compensation is not conducive to the control of the cleanliness of molten steel and the secondary oxidation of molten steel; moreover, it is necessary to increase the compensation of molten steel tanks to meet the smooth production of the process, occupying materials, and the energy consumption of the process and the cost of smelting will increase significantly