Method for manufacturing steel

A manufacturing method and technology of molten steel, applied in the direction of manufacturing converters, improving process efficiency, etc., can solve problems such as insufficient reduction effect, and achieve the effect of low occurrence rate of defects

Active Publication Date: 2013-09-25
JFE STEEL CORP
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

On the other hand, in the technique disclosed in Patent Document 4, although this problem can be solved to some extent by controlling the P content by pretreatment of molten iron, there is a decrease in (T.Fe) in the ladle slag after adding the flux. The problem of insufficient effect

Method used

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  • Method for manufacturing steel
  • Method for manufacturing steel
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Examples

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Embodiment

[0064] After blowing the steel with a top-blown converter, the steel is tapped to the ladle for slag modification treatment under the two conditions of the inventive example and the comparative example shown below, and then refined with an oxygen top-blown vacuum degasser for the second time. Continuous casting was performed as a slab, and various iron and steel products were produced, and a process experiment was performed to compare the occurrence rate of defects caused by oxide-based inclusions in each product. In addition, both the inventive example and the comparative example used the taphole plug and the externally inserted slag plug to reduce the outflow of slag to the ladle during tapping, and at the same time, during continuous casting, the air was completely isolated during casting under an Ar gas atmosphere. Casting is carried out, and an automatic slag detector is installed near the nozzle at the lower part of the ladle to prevent slag from being involved.

[0065]...

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PUM

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Abstract

The invention relates to a method for manufacturing steel, wherein an advent rate caused by oxide inclusions is reduced. The steps are included as follows: a converter process for converting steel; a tapping process from steel fluid and slag to steel ladle; a slag modifying process, wherein after CaCO3 is added to the slag to generate CO2, A1 slag is spreaded to the slag to be reacted with FeO in the slag, the content of (T. Fe) is less than 10 weight% and the weight ratio of (CaO)/(Al2O3) is 1/2; a secondary refining process wherein deoxygenation is carried after decarburization is carried to the steel fluid with modified slag through an oxygen top-blown vacuum degasser, and [C] in the steel fluid is less than 100 weight ppm; and a continuous casting process, wherein secondary modified steel fluid is continuously casted, wherein the [O] in the steel fluid after secondary modification is less than 50 weight ppm.

Description

technical field [0001] The present invention relates to a method for producing high-cleanliness steel, and more specifically, to a method for producing high-cleanliness steel capable of reducing the incidence of defects caused by oxide-based inclusions, especially Al2O3-based inclusions in products. Background technique [0002] In recent years, as the demand for surface-treated steel sheets made of ultra-low carbon steel, which is mainly used for automobiles, has increased, the demand for improved workability, surface quality, and internal quality has increased. Further ultra-low carbonization and low oxidation in carbon steel. [0003] The existing ultra-low carbon steel smelting process is generally composed of the following steps: blowing oxygen into molten steel with a top-blown converter under atmospheric pressure, and performing rough decarburization until C: 0.03 to 0.05% by mass of blown iron with less oxidation loss. Smelting process; adding a slag modifier to mod...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/00C21C5/28
CPCY02P10/20C21C7/06C21C7/068C21C7/076
Inventor 高桥大辅松冈克彰
Owner JFE STEEL CORP
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