A method for reducing aluminum oxide inclusions in semi-steelmaking steelmaking slabs

A technology of alumina and casting slabs, applied in the manufacture of converters, etc., can solve problems such as increased consumption of aluminum and iron, increased production costs, unfavorable performance of molten steel and steel products, etc., to improve the quality of cast slabs, reduce deoxidation costs, and prevent Al2O3 inclusions Reduced effect

Active Publication Date: 2020-04-28
PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The high oxygen content not only increases the consumption of aluminum and iron, increases the production cost, but also causes the Al 2 o 3 The increase of inclusions will adversely affect the casting of molten steel and the performance of finished steel products

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] The 140t converter adopts semi-steel steelmaking to smelt Q235 steel grade, and the process path is as follows:

[0035] Molten iron pretreatment → top-bottom combined blowing converter → RH → continuous casting.

[0036] Hot metal: C 3.2-4.1wt%, Si 0.015-0.030wt%, Mn 0.02-0.04wt%, P 0.06-0.08wt%, S≤0.025wt%.

[0037] The KR method is used for desulfurization to pretreat the molten iron, and the sulfur content in the molten iron after pretreatment is ≤0.015%.

[0038] The specific method of top-bottom combined blowing converter is as follows:

[0039] Put molten iron at 1300~1360℃ and start blowing oxygen, the oxygen flow rate is 30000Nm 3 / h. Start adding auxiliary materials after 3 minutes of blowing.

[0040] The oxygen lance nozzle is 1.4-2m away from the metal liquid surface of the molten pool, the blowing lance is 1.4m-1.8m, the blowing lance is 2m, and the carbon pulling lance is 1.4m. The gun position of the oxygen lance refers to the distance from the end ...

Embodiment 2

[0045] According to the method described in Example 1, semi-steel steelmaking is used to smelt Q235 steel; the difference from Example 1 is that the control requirements of the top-bottom combined blowing converter are that the end point carbon content is 0.07%, and the end point temperature is 1670 ° C. The sliding plate slag blocking system is adopted in the tapping process of the converter, and the amount of slag dropped is controlled to 29mm, and the aluminum-iron deoxidation is not used in the tapping process of the converter.

[0046] The treatment requirements of the RH process are that the RH entry temperature is 1610°C, and carbon deoxidation is carried out directly; the RH entry cycle is 4.5min, and the deoxidation alloying is carried out.

Embodiment 3

[0048] According to the method described in Example 1, semi-steel steelmaking is used to smelt Q235 steel; the difference from Example 1 is that RH enters the station and circulates for 4 minutes for deoxidation and alloying.

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PUM

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Abstract

The invention provides a method for reducing aluminum oxide inclusion in a semi-steel steelmaking casting blank. The method comprises the steps that molten iron pretreatment, top-bottom combined blowing converter smelting, vacuum circulating degassing refining and continuous casting are sequentially conducted, and the casting blank is obtained, wherein carbon deoxidization is conducted at the inlet temperature ranging from 1,595 DEG C to 1,620 DEG C in the vacuum circulating degassing refining process. Compared with the prior art, the method has the advantages that the vacuum circulating degassing refining procedure is conducted in the semi-steel smelting process, deoxidization is conducted by controlling the inlet temperature in the vacuum circulating degassing refining process, aluminum-iron deoxidization does not need to be adopted in the top-bottom combined blowing converter smelting process, and therefore the deoxidization cost is reduced; in addition, by adopting the method, the Al2O3 inclusion in the casting blank can be reduced, and the quality of the casting blank can be improved.

Description

technical field [0001] The invention relates to the technical field of steelmaking, in particular to a method for reducing alumina inclusions in semi-steelmaking steelmaking slabs. Background technique [0002] Panzhihua Iron and Steel Vanadium Converter adopts semi-steel steelmaking. Since the Si content in semi-steel is traces, the C content is lower than that of molten iron and the heat source is insufficient, so compared with molten iron steelmaking, semi-steel steelmaking needs to add SiO 2 , FeO and Fe 2 o 3 Composite slag, the post-smelting control needs to blow more oxygen to meet the end point temperature control requirements, resulting in low C content and high oxygen activity in the semi-steel steelmaking end point, the average end point oxygen content is 650ppm, and the end point oxygen content is partial high. [0003] The high oxygen content not only increases the consumption of aluminum and iron, increases the production cost, but also causes the Al 2 o 3...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21C7/06C21C5/35C21C7/10
CPCC21C5/35C21C7/06C21C7/10
Inventor 陈路曾建华梁新腾陈均
Owner PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
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