Method capable of improving quality of large-section peritectic steel continuous casting billet

A continuous casting billet and large-section technology, applied in the field of metallurgy, can solve the problems of affecting the mechanical properties of the finished steel plate, slowing down the growth of the billet shell, and high surface temperature of the billet shell, so as to reduce the content of inclusions and reduce the surface cracks of the billet. , the effect of high melting rate

Inactive Publication Date: 2018-03-27
WUYANG IRON & STEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Center segregation causes the enrichment of impurity elements in the center, and will be accompanied by the generation of inclusions, which seriously affects the mechanical properties of the finished steel plate
[0004] The prior art method is to use a weak cooling system to avoid the expansion of cracks during secondary cooling, but this will cause the growth of the slab shell in the seconda

Method used

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  • Method capable of improving quality of large-section peritectic steel continuous casting billet
  • Method capable of improving quality of large-section peritectic steel continuous casting billet
  • Method capable of improving quality of large-section peritectic steel continuous casting billet

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Embodiment 1

[0053] In this embodiment, the continuous casting slab of large-section cladding steel has a cross-sectional size of 330×2400 mm, and the material of the slab is Q345R.

[0054] The production method of the continuous casting slab of large-section cladding steel in this embodiment is as follows:

[0055] The molten steel is smelted in a converter, refined in an LF furnace, and then transferred to a VD furnace for vacuum deoxidation and degassing. After the vacuum is completed, 2.0kg / t of steel is fed into the calcium wire for final deoxidation and inclusion denaturation treatment, and softening before casting. Blow for 10 minutes, T[Ca] / [Al]s is 0.11, which promotes the floating of inclusions. The aluminum content in molten steel is 0.025%, the gas and impurity element content is: T[N]: 40ppm, T[O]: 15ppm, T[H]: 1.5ppm, T[S]: 0.003%, T[P] : 0.005%.

[0056] The molten steel is cast into the tundish at 1575°C, and the superheat of the tundish is 55°C. During continuous casti...

Embodiment 2

[0063] In this embodiment, the continuous casting slab of large-section cladding steel has a section size of 300×2400mm, and the material of the slab is Q690D.

[0064] The production method of the continuous casting slab of large-section cladding steel in this embodiment is as follows:

[0065] The molten steel is smelted in a converter, refined in an LF furnace, and then transferred to a VD furnace for vacuum deoxidation and degassing. After the vacuum is completed, 2.2kg / t of calcium wire is fed into the steel for final deoxidation and inclusion denaturation treatment, and softening before casting. After blowing for 11 minutes, T[Ca] / [Al]s is 0.13, which promotes the floating of inclusions. The aluminum content in molten steel is 0.030%, the gas and impurity element content is: T[N]: 40ppm, T[O]: 20ppm, T[H]: 1.5ppm, T[S]: 0.004%, T[P] : 0.004%.

[0066] The molten steel is cast into the tundish at 1570°C, and the superheat of the tundish is 50°C. During continuous casti...

Embodiment 3

[0073] In this embodiment, the continuous casting slab of large-section cladding steel has a section size of 330×2100mm, and the material of the slab is AB / EQ70.

[0074] The production method of the continuous casting slab of large-section cladding steel in this embodiment is as follows:

[0075] The molten steel is smelted in a converter, refined in an LF furnace, and then transferred to a VD furnace for vacuum deoxidation and degassing. After the vacuum is completed, 2.5kg / t of calcium wire is fed into the steel for final deoxidation and inclusion denaturation, and softening before casting. After blowing for 11 minutes, T[Ca] / [Al]s is 0.12, which promotes the floating of inclusions. The aluminum content in molten steel is 0.033%, the gas and impurity element content is: T[N]: 35ppm, T[O]: 15ppm, T[H]: 1.5ppm, T[S]: 0.002%, T[P] : 0.005%.

[0076] The molten steel is cast into the tundish at 1580°C, and the superheat of the tundish is 60°C. During continuous casting and c...

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Abstract

The invention discloses a method capable of improving the quality of a large-section peritectic steel continuous casting billet. The method comprises control over the following processing steps that (1) the chemical ingredients of low-alloy peritectic steel are optimized; (2), after VD treatment, a fed calcium line is controlled to perform final deoxidation and inclusion modification treatment, and soft blowing is performed before casting; (3), full package operation is adopted for a tundish, the tonnage is controlled, and low-liquid-level casting is avoided; (4), the superheat degree of the tundish is controlled in the continuous-casting throwing process, and meanwhile the temperature difference of molten steel between two furnaces is controlled; (5), the fed-water temperature of a crystallizer and the temperature difference between fed water and discharged water are controlled, meanwhile, the narrow edge taper of the crystallizer is increased, and the shrinkage quantity of the peritectic steel is compensated; (6), casting powder special for the peritectic steel is selected, wherein the casting powder is high in alkalinity, low in viscosity and high in melting rate; (7), after thecontinuous casting billet is controlled to enter a secondary cooling zone by 12 meters, electromagnetic stirring is applied, and meanwhile the secondary cooling water amount is lowered. The surface quality and the internal quality of the large-section peritectic steel continuous casting billet cast through the method are both improved to a great extent.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method capable of improving the quality of continuous casting slabs of large-section cladding steel. Background technique [0002] Continuous casting slab cracks are an important obstacle to the production of defect-free slabs, especially when casting large-section cladding steel, the probability of slab quality defects is much higher than that of other small-section types of steel. It can be seen from the iron-carbon equilibrium phase diagram that at 1495°C, iron-carbon alloys with [C] of 0.09-0.17% will undergo peritectic reactions during solidification, and will obtain a non-equilibrium containing δ phase at the end of crystallization. tissue, leading to local air gaps, and local "hot spots" in crack-sensitive areas. At this time, the heat output is small, the billet shell is thin, and the surface is prone to depressions, and the cooling and solidification sp...

Claims

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Application Information

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IPC IPC(8): B22D11/18B22D11/16B22D11/11
CPCB22D11/18B22D11/11B22D11/16
Inventor 王通邓建军李杰龙杰王九清肜玲华庞辉勇钟金红车金锋吴涛罗应明
Owner WUYANG IRON & STEEL
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