Method for producing ultra-low phosphorus steel in argon blowing station by using premelted calcium ferrite to refine molten steel outdoors

Abstract

The invention provides a method for producing ultra-low phosphorus steel in an argon blowing station by using the premelted calcium ferrite to refine the molten steel outdoors, mainly comprising the following steps: tapping steel from a converter, refining in the argon blowing station to dephosphorize deeply, slagging, adjusting temperature, stirring, deoxidizing, refining, alloying and casting continuously. By using the method to dephosphorize deeply, the dephosphorization rate can be more than 80%, the content of phosphorus in the molten steel is controlled below 0.003% stably, the dephosphorization efficiency is high and stable, the smelting intensity of the converter is reduced, the service life of the converter is prolonged, the consumption of lime, oxygen and iron and steel materials is reduced, the electric energy is saved, 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 process of refining outside the furnace, especially in the process of refining molten steel outside the furnace using pre-melted calcium ferrite in an argon blowing station. Method for producing ultra-low phosphorus steel. 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 should be strictly controlled. In traditional technology, the phosphorus in steel is generally required to be controlled below 0.02%. Howeve...

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