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Dechroming carbon-maintaining method for smelting Cr-containing molten iron through top-bottom combined blowing converter and application

A converter smelting and top-bottom re-blowing technology is applied in the field of dechromizing and carbon-preserving Cr-containing molten iron in top-bottom combi-blowing converter smelting, and in the field of dechromizing and carbon-preserving in converter smelting Cr-containing molten iron, which can solve huge cost losses and increase converter steel production. Material consumption, enhanced oxidation of molten steel in converter, etc.

Active Publication Date: 2020-10-13
DAYE SPECIAL STEEL CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the converter smelting of Cr-containing molten iron is all research on decarburization and chromium preservation, but there is no research and development on how to control the end-point Cr content of the converter in the relevant literature and patents, and the low-chromium standard requirements for the production of Cr-containing molten iron in the converter For steel types, it is mainly to reduce the excessively high residual Cr in the steel by supplementary blowing in the later stage and increasing the oxygen content in the steel.
This process not only increases the oxidation of molten steel in the converter, increases the consumption of deoxidized alloys, increases the consumption of steel materials in the converter, and causes huge cost losses, but also increases the quality risk of large particle inclusions in the steel

Method used

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  • Dechroming carbon-maintaining method for smelting Cr-containing molten iron through top-bottom combined blowing converter and application
  • Dechroming carbon-maintaining method for smelting Cr-containing molten iron through top-bottom combined blowing converter and application
  • Dechroming carbon-maintaining method for smelting Cr-containing molten iron through top-bottom combined blowing converter and application

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0061] Add scrap steel with a weight of 28.1t and a Cr element content of ≤0.08% into a 120t top-bottom combined blowing converter. The blending temperature is 1376°C. : 0.18%, molten iron with a weight of 106t (the ratio of molten iron is 79.06%) is smelted, wherein the bottom blowing gas is nitrogen, and the bottom blowing mode is set as: from the start of blowing to the start of blowing for 5 minutes, and the flow rate of the inert gas is controlled at 0.12 N m 3 min -1 ·t -1 , 6-12 minutes after the opening of the blowing, the flow rate of the bottom blowing inert gas is controlled at 0.05Nm 3 min -1 ·t -1 ; From the 13th minute after the opening of the blowing to the end of the inert gas blowing, the flow rate of the bottom blowing inert gas is controlled at 0.04Nm 3 min -1 ·t -1 . After the blowing is started, the gun position is controlled at 1.3-2.0m, 1278kg of magnesium balls and 963kg of lightly burned dolomite are added within the first 3 minutes, then a tot...

Embodiment 2

[0063] Add scrap steel with a weight of 27t and a Cr element content of ≤0.08% into a 120t top-bottom combined blowing converter. The blending temperature is 1375°C, and the composition contains C: 4.37%, Si: 0.62%, P: 0.110%, Cr: 0.22% molten iron with a weight of 104.6t (the molten iron ratio is 79.48%) for smelting, wherein the bottom blowing gas is nitrogen, and the bottom blowing mode is set as: from the start of blowing to the start of blowing for 5 minutes, and the flow rate of the inert gas is controlled at 0.12 N m 3 min -1 ·t -1 , 6-12 minutes after the opening of the blowing, the flow rate of the bottom blowing inert gas is controlled at 0.05Nm 3 min -1 ·t -1 ; From the 13th minute after the opening of the blowing to the end of the inert gas blowing, the flow rate of the bottom blowing inert gas is controlled at 0.04Nm 3 min -1 ·t -1 . After the blowing is started, the gun position is controlled at 1.3-2.0m, 1498kg of magnesium balls and 2067kg of lightly bu...

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Abstract

The invention discloses a dechroming carbon-maintaining method for smelting Cr-containing molten iron through a top-bottom combined blowing converter. The dechroming carbon-maintaining method comprises the following steps: filling Cr-containing molten iron and waste steel into the top-bottom combined blowing converter, adding a slagging material, blowing oxygen gas by a top gun from smelting startto smelting end, blowing inert gases by a bottom gun, and smelting, wherein Cr element content of Cr-containing molten iron is as follows: less than or equal to 0.25wt% of Cr; Cr element content in waste steel is as follows: less than or equal to 0.08wt% of Cr; and adding amount of Cr-containing molten iron accounts for 78.0wt%-82.96wt% of total mass of the Cr-containing molten iron and the wastesteel. The dechroming carbon-maintaining method has the beneficial effect of breaking through the technical bottleneck that Cr-containing molten iron cannot meet requirements of controlling residualCr to be less than or equal to 0.08% in aspect of a converter smelting process, realizes smelting of the Cr-containing molten iron and waste steel through the top-bottom combined blowing converter, and achieves the target that the final-point Cr is less than or equal to 0.08%.

Description

technical field [0001] The invention relates to a chromium-removing and carbon-preserving method for smelting Cr-containing molten iron in a converter, in particular to a chromium-removing and carbon-preserving method for smelting Cr-containing molten iron in a converter with top-bottom combined blowing, and belongs to the technical field of converter steelmaking. Background technique [0002] Chromium is a beneficial element for most steel types, it can improve the strength, hardness, hardenability, heat resistance and wear resistance of steel, but at the same time for some special steel types, such as cord steel, etc., its The presence of Cr reduces the plasticity and toughness of steel, making Cr a harmful element. In recent years, with the adjustment of the blast furnace charge in the special steel industry, chromium is reduced to molten iron during the blast furnace ironmaking process, resulting in an increase in Cr content in molten iron, even as high as 0.25wt%, while...

Claims

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Application Information

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IPC IPC(8): C21C5/36C21C5/35
CPCC21C5/35C21C5/36Y02P10/20
Inventor 王震李博鹏柳萍潘明旭郑文超王品张光鸿王占忠朱国富张念史啸峰饶金元任康陈君陆竹君
Owner DAYE SPECIAL STEEL CO LTD
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