Method for improving submerged arc effect of refining initial stage of high carbon steel

A technology for high-carbon steel and tons of steel, which is applied in the field of improving the initial submerged arc effect of high-carbon steel refining, which can solve the problems of lower tapping temperature, prolonged slag melting time, and increased gas content, so as to reduce nitrogen absorption and improve molten steel Mass, Tension Reduction and Density Effects

Inactive Publication Date: 2017-09-15
HEBEI IRON AND STEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the liquidus temperature of high-carbon steel is low, the tapping temperature of the converter is also lowered accordingly, so the materials used for slag washing are easy to agglomerate on the surface of molten steel, prolonging the slag removal time in the early stage of molten steel refining, poor submerged arc effect, and arc light Ionize the oxygen and nitrogen in the air, causing the content of nitrogen, oxygen and other gases in the molten steel to increase

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] 120-ton converter system smelting high-carbon steel 60# steel;

[0023] The chemical composition and mass percentage of 60# steel in this example are: C: 0.57%, Si: 0.17%, Mn: 0.50%, P: 0.035%, S: 0.035%, Cr: 0.25%, Cu: 0.25%, Ni: 0.30%, the balance is Fe and unavoidable impurities.

[0024] The amount of calcium carbide added in the converter tapping process is 1.3kg / ton of steel, and the main chemical composition and mass percentage are: CaC 2 : 75-78%, P: 0.65-0.75%, S: 0.040-0.060%, so that the surface tension of the slag is reduced to 0.45N / m, and the slag density is reduced to 3.0kg / m³.

[0025] The addition amount of converter slag washing material is 1.6kg / ton of small grain ash and 2.5kg / ton of steel for refining slag.

[0026] The tapping temperature in the converter tapping process is 1629°C.

[0027] The refining entry temperature is 1530°C, the refining slag removal time is 285S, and the refining cycle is 42min.

[0028] The nitrogen content of incoming...

Embodiment 2

[0031] 120-ton converter system smelting high-carbon steel 81MnCrV;

[0032] The chemical composition and mass percentage of 81MnCrV in this example are: C: 0.79%, Si: 0.15%, Mn: 0.6%, P: 0.025%, S: 0.020%, Cr: 0.15%, V: 0.012%, and the balance It is Fe and unavoidable impurities.

[0033] The amount of calcium carbide added in the converter tapping process is 1.4kg / ton of steel, and the main chemical composition and mass percentage are: CaC 2 : 75-78%, P: 0.65-0.75%, S: 0.040-0.060%, so that the surface tension of the slag is reduced to 0.40N / m, and the slag density is reduced to 2.90kg / m³.

[0034] The addition amount of converter slag washing material is 1.6kg / ton of small grain ash and 2.5kg / ton of steel for refining slag.

[0035] The tapping temperature in the converter tapping process is 1625°C.

[0036] The refining entry temperature is 1522°C, the refining slag removal time is 251S, and the refining cycle is 43min.

[0037] The nitrogen content of incoming molten ...

Embodiment 3

[0040] 120-ton converter system smelting high-carbon steel 81MnCrV;

[0041] The chemical composition and mass percentage of 81MnCrV in this example are: C: 0.86%, Si: 0.35%, Mn: 0.9%, P: 0.020%, S: 0.015%, Cr: 0.25%, V: 0.022%, and the balance It is Fe and unavoidable impurities.

[0042] The amount of calcium carbide added in the converter tapping process is 1.5kg / ton of steel, and the main chemical composition and mass percentage are: CaC 2 : CaC 2 : 75-78%, P: 0.65-0.75%, S: 0.040-0.060%, so that the surface tension of the slag is reduced to 0.39N / m, and the slag density is reduced to 2.88kg / m³.

[0043] The addition amount of converter slag washing material is 1.6kg / ton of small grain ash and 2.5kg / ton of steel for refining slag.

[0044] The tapping temperature in the converter tapping process is 1622°C.

[0045] The refining entry temperature is 1525°C, the refining slag removal time is 237S, and the refining cycle is 41min.

[0046] The nitrogen content of incomin...

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Abstract

The invention discloses a method for improving the submerged arc effect of the refining initial stage of high carbon steel. The method comprises the steps that in the steel tapping process of a high carbon steel converter which conducts slag washing on molten steel, calcium carbide is added in a steel ladle to enable the surface tension of slag to be reduced to be 0.35-0.45 N/m and to enable the slag density to be reduced to be 2.8-3.0 kg/m<3>. According to the method, by utilizing impact kinetic energy of the molten steel in the steel tapping process, molten steel sensitive heat and a reaction of the calcium carbide and oxygen in the molten steel and the slag, the surface tension and density of the slag are reduced to adjust the slag condition in the steel ladle and improve the submerged arc effect in the refining initial stage, and thus oxygen absorption and nitrogen absorption in the refining process are reduced to achieve the purpose of improving the quality of the molten steel.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for improving the initial submerged arc effect of high-carbon steel refining. Background technique [0002] With the rapid development of the national economy, all walks of life have higher and higher requirements for steel quality. The fierce competition in the steel market forces steel companies to continuously transform and upgrade, and their products are gradually developing towards high-end and high-quality products. In order to ensure the production of high-purity and high-quality slabs, the molten steel must undergo slag washing and refining outside the furnace before pouring. [0003] Slag washing is a method of adding small grain ash, fluorite, refining slag and other materials together with the alloy material during the tapping process of the converter, and reducing the content of sulfur, phosphorus and non-metallic inclusions in the steel throug...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/064C21C7/076
CPCC21C7/0087C21C7/064C21C7/076Y02P10/20
Inventor 李亚厚胡心光康毅赵宇李亚彦蔡宏伟
Owner HEBEI IRON AND STEEL
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