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Control method of inclusions for smelting and hot-rolling automobile steel on CSP production line

A control method and technology for inclusions, applied in the direction of manufacturing converters, etc., can solve the problems of difficult control, short residence time, easy to become long strips, etc., to ensure surface quality, reduce production costs, and shorten the process flow. Effect

Active Publication Date: 2018-01-05
武汉钢铁有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Especially using the CSP production line: First, because the thin or extremely thin material produced by the CSP production line is more sensitive to the number and size of inclusions, and because the continuous casting casting speed is fast in the thin slab production process, the molten steel stays in the mold for a short time , the inclusions in the steel cannot be removed by floating. Therefore, the CSP production line is stricter on the size and quantity of the inclusions in the steel, and it is more difficult to control; second, compared with the conventional production line, in order to ensure continuous pouring, the general steel All of these need to be treated with Ca, but the calcium element is very active, and the effect of calcium treatment is affected by the Al content in the steel, the O content and the oxidization of slag, and it is difficult to control the stability of calcium treatment; thirdly, after Ca treatment, the Al 2 o 3 or Al 2 o 3 -MgO inclusions are denatured and easily form calcium-aluminate with a low melting point, which tends to become long strips during the rolling process, which is detrimental to the surface quality of hot-rolled automotive steel. If the Ca treatment makes the Al in the steel 2 o 3 or Al 2 o 3 -MgO inclusions transform into non-deformable calcium-aluminate inclusions, which will affect the fatigue life and stamping performance of automotive steel, which is detrimental to the performance of steel

Method used

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  • Control method of inclusions for smelting and hot-rolling automobile steel on CSP production line
  • Control method of inclusions for smelting and hot-rolling automobile steel on CSP production line
  • Control method of inclusions for smelting and hot-rolling automobile steel on CSP production line

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] A method for controlling inclusions in hot-rolled automotive steel smelted in a CSP production line, the steps of which are as follows:

[0037] 1) Carry out converter smelting, adopt double slag operation, and control the oxygen level at the end of the converter to 360ppm;

[0038] 2) Refining in LF furnace, control heating time at 16min, superheat at 15.5°C; add modifier at 1.0Kg / ton of steel, the composition of modifier is: Al content: 41.5wt%, CaO: 30.5 wt%, the rest is Al 2 o 3 ;

[0039] 3) Carry out deoxidation alloying in the RH furnace, while vacuum treatment, add desulfurizer according to 1.05Kg / / ton of steel, and add refining agent according to 1.75Kg / / ton of steel;

[0040] When the RH breaks the vacuum, the soft blowing of argon before feeding the calcium wire will be carried out immediately, the blowing time of argon is 4min, and the flow rate is controlled at 0.06Nm3 / min; Feed the calcium wire. After the calcium wire is fed, the flow rate of argon gas...

Embodiment 2

[0045] Inclusion control method for smelting hot-rolled automobile steel in CSP production line, the steps:

[0046] 1) Carry out converter smelting, adopt double slag operation, and control the oxygen level at the end of the converter to 390ppm;

[0047] 2) Refining in LF furnace, control heating time at 17min, superheat at 20°C; add modifier according to 0.66Kg / ton of steel, the composition of modifier is: Al content: 42wt%, CaO: 28wt%, The rest is Al 2 o 3 ;

[0048] 3) Carry out deoxidation alloying in the RH furnace, while vacuum treatment, add desulfurizer according to 1.15Kg / / ton of steel, and add refining agent according to 1.9Kg / / ton of steel;

[0049] After the RH breaks the vacuum, the soft blowing of argon before feeding the calcium wire will be carried out immediately. The argon blowing time is 3.5min, and the flow rate is controlled at 0.07Nm3 / min; The steel is fed into the calcium wire, and after the calcium wire is fed, the argon gas flow rate is 0.07Nm 3 ...

Embodiment 3

[0054] Inclusion control method for smelting hot-rolled automobile steel in CSP production line, the steps:

[0055] 1) Carry out converter smelting, adopt double slag operation, and control the oxygen level at the end of the converter to 381ppm;

[0056] 2) Refining in LF furnace, control heating time at 15.5min, superheat at 21°C; add modifier according to 0.7 Kg / ton of steel, the composition of modifier is: Al content: 42.5wt%, CaO: 32wt %, the rest is Al 2 o 3 ;

[0057] 3) Carry out deoxidation alloying in the RH furnace, while vacuum treatment, add desulfurizer according to 1.25Kg / / ton of steel, and add refining agent according to 1.95Kg / / ton of steel;

[0058] After the RH breaks the vacuum, soft blowing of argon before the calcium wire is carried out immediately, the blowing time of argon is 2.5min, and the flow rate is controlled at 0.05Nm 3 / min; after the soft blowing of argon gas before feeding the calcium wire, feed the calcium wire according to 0.4Kg / ton of s...

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Abstract

The invention provides a control method of inclusions for smelting and hot-rolling automobile steel on a CSP production line. The method comprises the steps of conducting LF refining; conducting deoxidation alloying in an RH furnace; conducting pouring to form blanks; and conducting subsequent process conventionally. By means of the method, under the condition of guaranteeing the use performance of users, the production cost can be reduced, and the technological process can be shortened. In the rolling process, the inner layer of the inclusions in morphology comprises Al2O3 or MgO-Al2O3 or coexistent Al2O3 and MgO-Al2O3, the surface layer of the inclusions comprises CaO-MgO-Al2O3 or CaS or is shaped like a sphere containing coexistent CaO-MgO-Al2O3 and CaS, so that no gap is generated between the inclusions and steel, the anti-fatigue performance of the steel is improved from originally 140 MPa or below to 155 MPa or above, and the improving rate is at least 10%. Moreover, the inclusions do not deform in the rolling process, the number of the large-particle inclusions greater than 20 microns in the steel can be controlled not to exceed 1% of the total inclusions, and the surface quality of the steel is guaranteed.

Description

technical field [0001] The invention relates to a method for smelting automobile steel, specifically belonging to a smelting method for smelting hot-rolled automobile steel in a CSP production line, specifically a method for controlling inclusions in smelting hot-rolled automobile steel in a CSP production line. Background technique [0002] Taking advantage of the advantages of CSP production lines to produce thin materials, the development of hot-rolled products instead of cold-rolled products for automotive steel is a new development direction of "low-cost, green manufacturing" for steel companies and automobile manufacturers. In order to improve the product competitiveness of Wuhan Iron and Steel Co., Ltd., and also to reduce the production cost of automobile steel, the applicant took the lead in the CSP production line to carry out hot forming steel, dual-phase steel, TRIP steel and Q&P steel, etc. species development. [0003] Replacing cold-rolled products with hot-r...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C5/30C21C7/10C21C7/064C21C7/06C21C7/00
Inventor 齐江华朱万军毛新平吴杰杨成威王春锋陈俊孚孙伟彭著刚
Owner 武汉钢铁有限公司