Method for reducing size of B-type inclusions in aluminum deoxidized steel

An inclusion and aluminum deoxidation technology, applied in the field of iron and steel metallurgy and steelmaking, can solve the problems of little research on inclusion control, hydrogen-induced cracks in pipeline steel pipes, which have not been completely resolved, so as to avoid length, reduce rating level, reduce The effect of shapeshifting ability

Active Publication Date: 2021-07-13
UNIV OF SCI & TECH BEIJING +2
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Large size CaO-Al in pipeline steel 2 o 3 -MgO inclusions will form point-chain B-type inclusions after rolling and deformation. During the process of pipeline steel transporting oil and natural gas, stress concentration will easily occur around B-type inclusions, resulting in hydrogen-induced cracks in pipeline steel pipes. has not been fully resolved
Previous studies were mainly regulated by various control methods of inclusions in molten steel, but there are few studies on the control of inclusions in molten steel solidification, cooling and heating

Method used

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  • Method for reducing size of B-type inclusions in aluminum deoxidized steel
  • Method for reducing size of B-type inclusions in aluminum deoxidized steel

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Embodiment 1

[0039] In the refining process of aluminum deoxidized steel, the molten steel is deoxidized by aluminum, and the inclusions are softly blown and stirred. The soft blowing time is 20 minutes, and the flow rate of argon blowing is 150NL / min, which promotes the floating and removal of large-sized alumina inclusions, and promotes Modification of inclusions; after slag removal, the thickness of slag in the ladle is 2.5 cm, and pre-melted refining slag with low melting point and high calcium-aluminum ratio is used. The main component of refining slag is 55% CaO-30% Al 2 o 3 -10% SiO2 2 -5% MgO, reduce the viscosity of refining slag, promote the adsorption and removal of inclusions and modify non-metallic inclusions; through feeding pure calcium wire calcium treatment, control the T.Ca content in the steel to 0.0011%, and the T.S content to 0.0015%. , to control inclusions in molten steel as CaO-Al 2 o 3 -MgO; In the continuous casting process of aluminum deoxidized steel, through...

Embodiment 2

[0041] In the refining process of aluminum deoxidized steel, the molten steel is subjected to aluminum deoxidation and soft blowing and stirring are carried out on the inclusions. The soft blowing time is 15 minutes, and the flow rate of argon blowing is 100NL / min, which promotes the floating and removal of large-sized alumina inclusions, and promotes the subsequent process. Modification of inclusions; after slag removal, the thickness of slag in the ladle is 2.5 cm, and pre-melted refining slag with low melting point and high calcium-aluminum ratio is used. The main component of refining slag is 55% CaO-30% Al 2 o 3 -10% SiO2 2 -5% MgO, reduce the viscosity of refining slag, promote the adsorption and removal of inclusions and modify non-metallic inclusions; through feeding pure calcium wire calcium treatment, control the T.Ca content in the steel to 0.0011%, and the T.S content to 0.0015%. , to control inclusions in molten steel as CaO-Al 2 o 3 -MgO; in the continuous cas...

Embodiment 3

[0043] In the refining process of aluminum deoxidized steel, the molten steel is deoxidized by aluminum, and the inclusions are softly blown and stirred. The soft blowing time is 18 minutes, and the flow rate of argon blowing is 200NL / min, which promotes the floating and removal of large-sized alumina inclusions, and promotes Modification of inclusions; after slag removal, the thickness of slag in the ladle is 2.5 cm, and pre-melted refining slag with low melting point and high calcium-aluminum ratio is used. The main component of refining slag is 55% CaO-30% Al 2 o 3 -10% SiO2 2 -5% MgO, reduce the viscosity of refining slag, promote the adsorption and removal of inclusions and modify non-metallic inclusions; through feeding pure calcium wire calcium treatment, control the T.Ca content in the steel to 0.0011%, and the T.S content to 0.0015%. , to control inclusions in molten steel as CaO-Al 2 o 3 -MgO; in the continuous casting process of aluminum deoxidized steel, through...

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Abstract

The invention belongs to the field of ferrous metallurgy steelmaking, and particularly relates to a method for reducing the size of B-type inclusions in aluminum deoxidized steel. Through the method, during refining, molten steel is subjected to aluminum deoxidation firstly, then the inclusions are subjected to soft blowing stirring, large-size aluminum oxide inclusions are promoted to float upwards so as to be removed, the size of the inclusions is reduced, through calcium treatment or adding of calcium-containing silicon iron in combination with a controlled cooling and controlled heating method, the inclusions in the continuous casting and heat treatment process are promoted to be converted into composite inclusions with a CaS outer layer and an Al2O3-MgO core and with higher hardness, the deformability of the inclusions in the rolling process is reduced, the size of B-type inclusions in the aluminum deoxidized steel is effectively reduced, and the grade of the B-type inclusions in the aluminum deoxidized steel is lower than 1.5. The method has the beneficial effects that the length of the B-type inclusions in the aluminum deoxidized steel can be effectively avoided, the grade of the B-type inclusions is reduced, the strength, toughness and other properties of the aluminum deoxidized steel can be effectively improved, and the failure of a product in the service process is avoided.

Description

technical field [0001] The invention belongs to the field of iron and steel metallurgy and steelmaking, and in particular relates to a method for reducing the size of B-type inclusions in aluminum-deoxidized steel. Background technique [0002] The composition, shape, size, and distribution of non-metallic inclusions in steel directly affect the surface quality and product performance of stainless steel, and are the top priority in the production of high-quality steel. Various inclusions and control technologies in the molten steel smelting process have become increasingly mature, and a series of mature inclusion control methods such as deoxidation, bubble flotation removal, slag modification, and alloy treatment modification have been formed, which can better realize smelting Process from refining to control of inclusions in molten steel for continuous casting. Starting from the converter or electric furnace tapping, the generation of inclusions can be controlled by deoxid...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/00C21C7/06C21D1/00B22D11/16C21C5/36
CPCC21C7/0006C21C7/06B22D11/16C21C5/36C21D1/00Y02P10/20
Inventor 张立峰任英杨文邓建军朱坦华李耀强陈子刚程迪李太全任强李亚琼陈威
Owner UNIV OF SCI & TECH BEIJING
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