Method for producing ultra-low phosphorus steel through applying pre-melting calcium ferrite to refine outside LF (Ladle Furnace) molten steel furnace

Abstract

The invention provides a method for producing ultra-low phosphorus steel through applying pre-melting calcium ferrite to refine outside an LF (ladle furnace) molten steel furnace. The method mainly the following steps: tapping through a converter, deeply removing phosphorus through an LF refining furnace (carrying out argon stirring on molten steel in the whole refining and phosphorus removal process), drossing, adjusting temperature and stirring, deoxidizing, refining, alloying and continuously casting. Deep phosphorus removal is carried out through the method, so that the phosphorus removal rate is more than 80%, the phosphorus content in the molten steel is lower than 0.003%, the phosphorus removal efficiency is high and stable, the smelting intensity of the converter is reduced, the service life of the converter is increased, and meanwhile, the lime consumption and the oxygen consumption are reduced, the electric energy is saved, the consumption of a steel material is reduced, and the metal yield is improved.

Description

technical field [0001] The invention belongs to the technical field of metallurgy and is used for removing phosphorus in steel by using pre-melted calcium ferrite in the refining process outside the furnace, especially applying pre-melted calcium ferrite in LF refining furnace (Ladle Furnace ladle refining furnace) The invention discloses a method for producing ultra-low phosphorus steel in the process of refining molten steel outside the furnace. Background technique [0002] Phosphorus is usually a harmful element in steel, because the segregation of phosphorus in steel is relatively serious, which deteriorates the toughness of steel and produces "cold brittleness", especially at low temperature conditions, it is more likely to occur "cold brittleness". Phosphorus segregation can also cause anisotropy of steel, reduce welding performance, and cause corrosion fatigue of stainless steel, so it must be strictly controlled. In traditional technology, the phosphorus in steel i...

AI Technical Summary

Problems solved by technology

[0003] At present, most steel mills adopt the "double slag method", that is, two slag making methods are used in the converter smelting; or the "duplex method", that is, the molten iron is smelted in one converter for half the time and then poured into another converter to continue smelting. The disadvantages of these two methods are that the process is complex, the smelting time is long, and the productivity of the converter cannot be fully utilized.

Another way is to carry out "three removals" on molten iron in advance, that is, desiliconization, desulfurization, and dephosphorization. For example, Japanese iron and steel enterprises have the disadvantages of requiring more equipment, large investment, complicated process, and large heat loss. The temperature of molten iron after "three removals" is low, which greatly reduces the amount of steel scrap added during converter smelting

Therefore, in order to produce these low-phosphorus and ultra-low-phosphorus steels, conventional converter smelting methods can no longer meet the phosphorus requirements of these steel types, so it is necessary to study the method of assisting dephosphorization by refining outside the furnace, so as to realize the production of ultra-low phosphorus steels