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Method of producing ultralow phosphoretic steel by extra furnace dephosphorization of molten steel

A technology for dephosphorization and ultra-low phosphorus steel outside the furnace, applied in the field of steel smelting, can solve the problems of large fluctuation of phosphorus content at the end of molten steel, difficulty in rapidly forming high basicity slag, and difficulty in producing low phosphorus steel, etc. Achieving good dephosphorization rate, reducing dephosphorization burden and stable effect

Inactive Publication Date: 2018-06-15
UNIV OF SCI & TECH BEIJING
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Problems solved by technology

Vanadium converter steelmaking in Xichang Steel is smelted with vanadium-extracted semi-steel. Due to the lack of slag-forming elements such as silicon and manganese in the semi-steel, the blowing of the smelting is the oxidation of carbon, which inhibits the formation of iron oxide in the slag, and the melting of lime is relatively low. Difficult, it is difficult to quickly form high alkalinity and high oxidizing slag, and the dephosphorization effect is unstable. In addition, the slag from the converter and the alloyed phosphorus return lead to large fluctuations in the phosphorus content at the end of the molten steel, and it is difficult to stably produce low Phosphorus steel

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  • Method of producing ultralow phosphoretic steel by extra furnace dephosphorization of molten steel

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Embodiment 1

[0022] A method for producing ultra-low phosphorus steel by dephosphorizing molten steel outside the furnace, the method comprising the following steps:

[0023] 1. Converter smelting for vanadium extraction

[0024] 2. Semi-steel tapping: after the smelting of the vanadium extraction converter is completed, the steel is tapped at a temperature ≥ 1350 °C and a carbon content ≥ 3.3%;

[0025] When tapping, the slag is used to tap the steel, and argon is blown throughout the tapping process;

[0026] Put the special flux for dephosphorization outside the furnace of semi-steel into the ladle at one time when 1 / 3 of the semi-steel is tapped, the amount of special flux for dephosphorization outside the furnace of semi-steel is 6.5-10kg / t The composition of lime is 35-45%, iron oxide 40-50%, fluorite 10-15%, industrial soda ash 5-10%;

[0027] After adding the dephosphorization flux, continue to tap until the end;

[0028] 3. Desulfurization: desulfurize after removing the slag a...

Embodiment 2

[0039] This embodiment is basically the same as Embodiment 1, the difference is that the composition of the special flux for dephosphorization outside the semi-steel furnace in this embodiment is 40% lime, 45% iron oxide, 10% fluorite, and 5% industrial soda ash. The dephosphorization effect is shown in Table 1.

[0040]

[0041] Example 1 and Example 6 are different experiments. Due to the influence of various factors, the composition of each furnace semi-steel produced by the steel factory is not completely consistent.

[0042] As can be seen from Table 1, adopting the method of the present invention can obtain considerable dephosphorization effect without increasing procedures and time, and the present invention utilizes the dephosphorization in the semi-steel tapping process to reduce the consumption of conventional converter dephosphorization flux , shorten the dephosphorization treatment time of the conventional converter, easy to use, high dephosphorization efficienc...

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Abstract

The invention relates to a smelting method of a steel type, in particular to a method of producing ultralow phosphoretic steel by extra furnace dephosphorization of molten steel. The method successively comprises the following steps: vanadium extracting converter smelting, vanadium extracting converter semisteel tapping, transferring of the semisteel to a desulfuration station to desulfurate, dephosphorization and decarbonization of converter steelmaking, refining and continuous casting. In the process of tapping semisteel in the vanadium extracting converter, special flux for semisteel extrafurnace dephosphorization is added into semisteel ladles at one time, drossing is avoided after the semisteel is tapped, and the semisteel is transferred to the esulfuration station to desulfurate anddross; the special flux for semisteel extra furnace dephosphorization comprises the following components in percentage by weight: 35-45% of lime, 40-50% of ferric oxide, 10-15% of fluorite and 5-10%of industrial sodium carbonate. The smelting method provided by the invention is convenient to operate and concise in process, and the phosphorus content in the steel is controlled below 0.005%.

Description

technical field [0001] The invention relates to a steel smelting method, in particular to a method for producing ultra-low phosphorus steel by dephosphorizing molten steel outside a furnace. Background technique [0002] At present, the production technologies of ultra-low phosphorus steel mainly include dephosphorization of molten iron pretreatment, converter dephosphorization, and dephosphorization of molten steel outside the furnace. There are two methods of molten iron dephosphorization pretreatment, one is powder spraying method: conveying with nitrogen or air, submerging the spray gun and spraying the powder into the bottom of the molten pool. The other is the bottom blowing method, the flux is added to the surface of the molten iron, and the bottom of the furnace blows N through the breathable brick. 2 Stir. Converter dephosphorization can be divided into conventional converter dephosphorization and double-slag dephosphorization. Conventional converter dephosphoriza...

Claims

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Application Information

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IPC IPC(8): C21C7/064
CPCC21C7/064C21C7/0645
Inventor 孙彦辉黄博白雪峰曾建华陈炼吴国荣
Owner UNIV OF SCI & TECH BEIJING
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