Composite sphere for manufacturing ultra-low phosphoretic steel with outside-stove refining dephosphorization and its manufacturing method

Abstract

The invention relates to a method for controlling phosphorus in the production of ultra-low phosphorous steel by microalloy steel and special steel, in particular to a compound sphere for producing the ultra-low phosphorous steel by external refining dephosphorization and a preparation method thereof. The compound sphere consists of a spherical core and a shell, wherein, the spherical core mainlycomprises dephosphorizing flux, calcium carbonate, magnesium carbonate or a mixture of the calcium carbonate and the magnesium carbonate, and the shell mainly comprises one of calcium oxide or magnesium oxide or a mixture of the calcium oxide and the magnesium oxide; and the compound sphere is prepared by material mixing, drying, and compound sphere preparation on sphere preparation equipment. The method has scientific formula and simple and reasonable process, can realize the quick refining dephosphorization of molten steel until the content of the phosphorus is lower than 0.0030 percent proven by application, is high in efficiency, steady and short in time, remedies the defect that the prior converter smelting is difficult to achieve the content of the phosphorus in the steel less than 0.01 percent, can meet the requirements of different molten steel on the content of the phosphorus, greatly improves the quality of refining steel, and reduces smelting cost.

Description

technical field [0001] The invention relates to a method for controlling phosphorus in micro-alloy steel, high-carbon steel and special steel to produce ultra-low phosphorus steel, in particular to a composite sphere used for refining and dephosphorizing outside the furnace to produce ultra-low phosphorus steel and its preparation method. The invention belongs to the technical field of metallurgy. Background technique [0002] It is well known that phosphorus is usually controlled as a harmful element in steel. Because the segregation of phosphorus in the steel is serious, the toughness of the steel is deteriorated, resulting in "cold brittleness", especially at low temperature conditions, it is more likely to occur "cold brittleness", and the segregation of phosphorus will also cause the anisotropy of the steel, reducing the Welding performance, causing corrosion fatigue of stainless steel. With the rapid development of science and technology, high-grade high-quality stee...

AI Technical Summary

Problems solved by technology

For this reason, most of the current steel mills use the "double slag method", that is, two slagging in the converter smelting, or the "duplex method", that is, one converter is used to smelt molten iron for half the time and then pour it into another converter to continue smelting. method, the shortcomings 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; there is another way to carry out "three removals" on the molten iron in advance, that is, desiliconization, desulfurization, and dephosphorization, such as Japanese iron and steel companies , its disadvantage is that it requires a lot of equipment, large investment, complex process, large heat loss, and because the temperature of molten iron after "three removals" is low, the amount of scrap steel added during converter smelting is greatly reduced

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