Continuous casting manufacturing method for low-carbon high-chromium ferrite corrosion-resisting steel small square billet

A small billet continuous casting and manufacturing method technology, applied in the field of iron and steel continuous casting, can solve the problems such as the difficulty of continuous casting production, the formation of cracks on the surface of the continuous casting billet, and the influence of the lubricating effect of the mold slag on the billet shell.

Active Publication Date: 2016-12-14
INST OF RES OF IRON & STEEL JIANGSU PROVINCE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, when there are many easily oxidizable alloying elements such as Cr in the steel, secondary oxidation easily occurs to form oxides, which affects the fluidity of molten steel. The lubricating effect of the continuous casting slab forms defects such as cracks on the surface of the continuous casting slab; at the same time, compared with ordinary carbon steel, this type of steel has the characteristics of small heat transfer coefficient and large solid-liquid phase temperature range. During the solidification process, it is easy to grow into coarse Columnar grain structure, so that defects such as intermediate cracks, central shrinkage cavities and central segregation are formed inside the billet
Therefore, the continuous casting production of this type of steel is more difficult

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] After molten steel smelting, the mass percentage of chemical composition of the finished product is controlled as follows: 0≤C≤0.02%; 0≤Si≤0.08%; 0≤Mn≤1.00%; 7.0%≤Cr≤9.0%; 0≤P≤0.03%; 0 ≤S≤0.02%; the rest is Fe and unavoidable impurity elements.

[0024] After the casting starts, when the molten steel in the ladle is injected into the tundish, and the tonnage of the molten steel in the tundish reaches 16 tons, put a single-layer high-alkalinity covering agent with a carbon content of 0.60% on the top of the molten steel in the tundish, and pass through the molten steel in the tundish. Manual temperature measurement and comparison with automatic temperature measurement results confirm that the superheat of the tundish is 38°C, control the water flow of the crystallizer to 1800L / min, and when the molten steel volume of the tundish reaches 35t, the 8 streams will move from the middle to the edge according to the symmetrical position Start pouring in turn, and add mold flux ...

Embodiment 2

[0029] After molten steel smelting, the mass percentage of chemical composition of the finished product is controlled as follows: 0≤C≤0.02%; 0≤Si≤0.08%; 0≤Mn≤1.00%; 7.0%≤Cr≤9.0%; 0≤P≤0.03%; 0 ≤S≤0.02%; the rest is Fe and unavoidable impurity elements.

[0030] After the casting starts, when the molten steel in the ladle is injected into the tundish, and the tonnage of the molten steel in the tundish reaches 16 tons, a single-layer high-alkalinity covering agent with a carbon content of 0.58% is placed on the top of the molten steel in the tundish, and the Manual temperature measurement and comparison with automatic temperature measurement results confirm that the superheat of the tundish is 35°C, control the water flow of the crystallizer to 1950L / min, and when the molten steel volume of the tundish reaches 35t, the 8 streams will move from the middle to the edge according to the symmetrical position Start pouring in turn, and add mold flux in turn. The C content in mold flux ...

Embodiment 3

[0035] After molten steel smelting, the mass percentage of chemical composition of the finished product is controlled as follows: 0≤C≤0.02%; 0≤Si≤0.08%; 0≤Mn≤1.00%; 7.0%≤Cr≤9.0%; 0≤P≤0.03%; 0 ≤S≤0.02%; the rest is Fe and unavoidable impurity elements.

[0036]After the casting starts, when the molten steel in the ladle is poured into the tundish, and the tonnage of the molten steel in the tundish reaches 16 tons, a single-layer high-alkalinity covering agent with a carbon content of 0.49% is placed on the top of the molten steel in the tundish, and the Manual temperature measurement and comparison with automatic temperature measurement results confirm that the superheat of the tundish is 23°C, control the water flow of the crystallizer to 1750L / min, and when the molten steel volume of the tundish reaches 35t, the 8 streams will move from the middle to the edge according to the symmetrical position Start pouring in turn, and add mold flux in turn. The C content in mold flux is ...

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Abstract

The invention discloses a continuous casting manufacturing method for a low-carbon high-chromium ferrite corrosion-resisting steel small square billet. The continuous casting manufacturing method is characterized in that the continuous casting superheat temperature is controlled to be 20-40 DEG C, the drawing speed is 2.2-2.6 m / min, the cooling water volume of a crystallizer is 1750-1950 L / min, the vibration frequency of the crystallizer is 190-220 Hz, the vibration amplitude is 6.5-9.5 mm, the protection slag basicity of the crystallizer is 0.65-0.90, the melting point temperature is 1020-1060 DEG C, and at the temperature of 1300 DEG C, the viscosity is 0.35-0.60 Pa.s; and the M-EMS and F-EMS combined control mode is adopted in the continuous casting process, the current intensity of the M-EMS is 280-320 A, the frequency of the M-EMS is 3-6 Hz, the current intensity of the F-EMS is 400-600 A, and the frequency of the F-EMS is 10-15 Hz. According to the low-carbon high-chromium ferrite corrosion-resisting steel small square billet produced through the method, the low-power acid pickling qualified rate is 95% or over, the surface of the small square billet is free of obvious cracks and other defects, the average depth of oscillation marks is smaller than or equal to 0.24 mm, the small square billet can directly enter the next steel rolling procedure for production without being subjected to surface flame treatment, and the requirements of customers are met.

Description

technical field [0001] The invention relates to the technical field of continuous casting of iron and steel, in particular to a method for continuous casting of low-carbon, high-chromium, corrosion-resistant steel billets. Background technique [0002] Corrosion-resistant steel refers to steel that can resist corrosion in some strong corrosive media. Adding a certain amount of Cr element to the corrosion-resistant steel can form a layer of Cr oxide film on the surface, which can significantly improve the corrosion resistance of the steel; by reducing the C content in the steel, the Cr can be reduced. 23 C 6 Precipitate at the grain boundary to improve its resistance to intergranular corrosion; through the control of the content of alloy elements Cr and C, it can obtain a ferrite solidification structure, which can improve its resistance to oxidative medium corrosion. Therefore, low-carbon high-chromium corrosion-resistant steel has excellent performance in corrosion resist...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22D11/22B22D11/16C22C38/18C22C38/02C22C38/04
CPCB22D11/002B22D11/16B22D11/166B22D11/225C22C38/02C22C38/04C22C38/18
Inventor 周青峰邹长东赵家七孙凤梅麻晗
Owner INST OF RES OF IRON & STEEL JIANGSU PROVINCE
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