Smelting method of low phosphate steel

A smelting method and low-phosphorus steel technology, which are applied in the smelting field of low-phosphorus steel, can solve the problems of low terminal temperature of converter and fluctuation of dephosphorization effect, etc., so as to improve slag effect, reduce splash phenomenon, and promote dephosphorization reaction. Effect

Inactive Publication Date: 2018-12-07
INST OF RES OF IRON & STEEL JIANGSU PROVINCE +2
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  • Application Information

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Problems solved by technology

The disadvantage of this method of smelting is that the end point temperature of the converter is generally not high, and the dephosphorization effect fluctuates to a certain extent.

Method used

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Examples

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Effect test

Embodiment 1

[0040] A 120t top-bottom double-blown converter in a factory adopts this method to smelt cord steel. Using molten iron and scrap steel as raw materials, blowing is carried out in two stages. The first blowing completes desiliconization and dephosphorization, and the second blowing is carried out after the slag is poured. Decarburization, heating, and finally tapping.

[0041]The control parameters of the converter steelmaking process are shown in Table 1. The impact depth of the molten pool h = molten pool depth × impact coefficient, unit cm, the depth of the molten pool is measured by the sub-lance, the impact coefficient is controlled at 0.5-0.7, θ is 12.5°, and the throat diameter D of the oxygen lance nozzle is 3.73cm. When the working oxygen pressure P1 is 0.84MPa, the position H of the oxygen blowing lance is 1.5m; when the working oxygen pressure P1 is 0.69MPa, the position H of the oxygen blowing lance is 1.8m; 1500kg; lift the gun at the end of the first blowing, add...

Embodiment 2

[0046] A 120t top-bottom double-blown converter in a factory adopts this method to smelt cord steel. Using molten iron and scrap steel as raw materials, blowing is carried out in two stages. The first blowing completes desiliconization and dephosphorization, and the second blowing is carried out after the slag is poured. Decarburization, heating, and finally tapping.

[0047] The control parameters of the converter steelmaking process are shown in Table 2. The impact depth of the molten pool h = molten pool depth × impact coefficient, unit cm, the depth of the molten pool is measured by the sub-lance, the impact coefficient is controlled at 0.5-0.7, θ is 12.5°, and the throat diameter D of the oxygen lance nozzle is 3.73cm. When the working oxygen pressure P1 is 0.84MPa, the position H of the oxygen blowing lance is 1.45m; when the working oxygen pressure P1 is 0.69MPa, the position H of the oxygen blowing lance is 1.75m; lime is added at one time for a blowing, and the additi...

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Abstract

The invention relates to a smelting method of low phosphate steel. The method comprises the steps of molten iron desulphurization, waste steel adding and molten iron adding, converter primary blowing,deslagging, converter secondary blowing, and deslagging tapping. A double slag process is used for smelting, particularly, through control over the furnace inlet molten iron ratio and adoption of a material adding method, an oxygen supply method and a bottom blowing method which are matched, smelting of high-temperature high-carbon low phosphate steel is achieved; the smelting molten iron ratio is controlled according to the molten iron temperature and the molten iron silicon content, the primary blowing time is controlled to range from 5 min to 7 min, the variable gun variable oxygen pressure oxygen blowing mode is adopted, according to the molten iron silicon content, the lime adding amount is controlled, before secondary blowing gun lowering, a certain amount of temperature rising agent is added, the tapping temperature is controlled to be above 1670 DEG C, the tapping carbon content is controlled to above 0.1%, the process structure is adopted for producing, and the content of converter end point phosphorus is stably controlled to below 0.008%.

Description

technical field [0001] The invention belongs to the technical field of converter steelmaking, and in particular relates to a method for smelting low phosphorus steel. Background technique [0002] Phosphorus is generally considered as a harmful impurity in steel, which is easy to segregate at the grain boundary, causing the steel to be "cold and brittle", and significantly reducing the low temperature impact toughness of the steel. With the increasing demand for high-quality steel, the requirements for phosphorus content in steel are higher. At present, the technologies for reducing the phosphorus content in molten steel mainly include molten iron injection pre-dephosphorization, double converter dephosphorization, converter double slag dephosphorization, etc. [0003] The hot metal pre-dephosphorization process was first developed and applied by Japanese steel enterprises. The process is roughly as follows: after desiliconization treatment in the blast furnace tap trough, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C5/35C21C5/36
CPCC21C5/35C21C5/36Y02P10/20
Inventor 管挺邹长东刘飞王耀
Owner INST OF RES OF IRON & STEEL JIANGSU PROVINCE
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