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Method for smelting low-phosphorus steel with semisteel

A low-phosphorus steel and steel smelting technology, which is applied in the field of metallurgical steelmaking, can solve the problems of the loss of iron elements in the smelting cycle, the influence of smelting low-phosphorus steel, and the increase of steel-making costs, so as to reduce the consumption of molten iron, reduce slag, and reduce smelting. The effect of steel cost

Inactive Publication Date: 2019-09-13
HEBEI IRON AND STEEL +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It is difficult to slag in the initial stage of semi-steel smelting and the temperature is higher than that of ordinary molten iron, which affects the smelting of low-phosphorus steel
[0003] In the prior art, one is to add a dephosphorization agent to improve the dephosphorization effect, and this type of dephosphorization agent will inevitably increase the cost of steelmaking; the other is to use a double slag dephosphorization method. Although this type of method consumes less slag, However, the slag dumping process will cause the loss of iron elements and prolong the smelting cycle

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] A kind of semi-steel smelting method for low-phosphorus steel of the present embodiment comprises the following steps:

[0025] (1) Keep all the slag in the last furnace of the steelmaking converter, and do slag splashing to protect the furnace by adding 4.3kg / t steel dolomite. The nitrogen pressure is controlled at 1.2MPa; the vanadium-containing molten iron is mixed into the vanadium extraction converter for vanadium extraction operation. After the vanadium is extracted and the semi-steel is produced, the temperature of the semi-steel is 1385°C. Semi-steel: C: 4.01%, S: 0.045%, P : 0.135%; add 5kg / t of lime into the half-ladle, and add it from the high-level silo to the liquid surface of the half-ladle to pre-melt the lime;

[0026] (2) After the steelmaking converter is mixed with semi-steel, it is then mixed with scrap steel. The amount of scrap steel added is 136㎏ / t steel, including 40kg / t steel of slag iron and 96kg / t steel of pure scrap steel, which are added by ...

Embodiment 2

[0031] A kind of semi-steel smelting method for low-phosphorus steel of the present embodiment comprises the following steps:

[0032] (1) Keep all the slag in the last furnace of the steelmaking converter, and do slag splashing to protect the furnace by adding 3.8kg / t steel dolomite. The nitrogen pressure is controlled at 1.4MPa; the vanadium-containing molten iron is mixed into the vanadium extraction converter for vanadium extraction operation. After the vanadium is extracted and the semi-steel is produced, the temperature of the semi-steel is 1395°C. Semi-steel: C: 3.95%, S: 0.035%, P : 0.155%; add lime 3.5㎏ / t steel into the half ladle, add it from the high-level silo to the liquid surface of the half ladle, and pre-melt the lime;

[0033] (2) After the steelmaking converter is mixed with semi-steel, it is then mixed with scrap steel. The amount of scrap steel added is 130㎏ / t steel, including 40kg / t steel of slag iron and 90kg / t steel of pure scrap steel, which are added b...

Embodiment 3

[0038] A kind of semi-steel smelting method for low-phosphorus steel of the present embodiment comprises the following steps:

[0039] (1) Keep all the slag in the previous furnace of the steelmaking converter, and add 4.1kg / t steel dolomite to protect the furnace by splashing slag. The nitrogen pressure is controlled at 1.0MPa; the vanadium-containing molten iron is mixed into the vanadium extraction converter for vanadium extraction operation. After the vanadium is extracted and the semi-steel is produced, the temperature of the semi-steel is 1420°C. Semi-steel: C: 3.75%, S: 0.050%, P : 0.138%; add lime 2.5㎏ / t steel into the half ladle, add it to the liquid surface of the half ladle from the high-level silo, and pre-melt the lime;

[0040] (2) After the steelmaking converter is mixed with semi-steel, it is then mixed with scrap steel. The amount of scrap steel added is 140㎏ / t steel, of which slag iron is 45㎏ / t steel and pure scrap steel is 95kg / t steel, which is added by cra...

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Abstract

The invention discloses a method for smelting low-phosphorus steel with semisteel. The method specifically comprises the following steps that, lime is added into a vanadium extraction semisteel ladle,the lime is subjected to pre-melting, the semisteel is added into a steel converter, and then steel strap is added into the steel converter; slag is added into the steel converter for slugging at theearly stage of blowing, the alkalinity of the slag is adjusted by adding the lime and dolomite, the alkalinity of the slag is 1.5-2.0, the molten steel temperature is controlled to be 1450-1500 DEG Cwithin the first 6 minutes during the early blowing; after blowing for 6 minutes, the lime and a heat-supplementing agent are added into the steel converter; and the alkalinity of the final slag is 2.5-3.0, the final molten steel temperature is 1630 to 1670 DEG C, and the final molten steel comprises 0.06%-0.10% of C, 0.01%-0.08% of S and 0.001%-0.010% of P. According to the method, the final phosphorus content of the molten steel is controlled to be less than 0. 010%, so that the high scrap ratio, the low iron loss, the low slag charge and the fast production can be realized.

Description

technical field [0001] The invention belongs to the technical field of metallurgy and steelmaking, and in particular relates to a method for smelting low-phosphorus steel from semi-steel. Background technique [0002] In the production process of vanadium-containing molten iron, the vanadium extraction operation is carried out first. The molten iron after vanadium extraction is called semi-steel. Converter blowing uses semi-steel plus scrap steel as raw materials. Phosphorus is a harmful element in steel, and the lower the content, the lower the effect on the performance of the steel bar. The temperature of semi-steel after vanadium-containing molten iron is higher than that of ordinary molten iron, and there are traces of Si, Mn and other elements. In the initial stage of semi-steel smelting, it is difficult to slag and the temperature is higher than that of ordinary molten iron, which affects the smelting of low-phosphorus steel. [0003] In the prior art, one is to add ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/064C22C33/06C22C38/00C21C7/00
CPCC21C7/005C21C7/064C22C33/06C22C38/002Y02P10/20
Inventor 何晴李一峰张东李彦军张兴隆
Owner HEBEI IRON AND STEEL