Method for preventing silicon content from increasing during smelting of ultra-low-carbon and ultra-low-silicon steel

A smelting process, ultra-low carbon technology, applied in the manufacture of converters and other directions, can solve problems such as insufficiency, and achieve the effect of solving the problem of silicon addition, reducing the rate of change of judgment, and improving economic benefits

Active Publication Date: 2019-09-24
武汉钢铁有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this patented method can only increase the silicon content of molten steel by less than 0.02% in the entire smelting process, which is only suitable for conventional low-silicon steel; and ultra-low-carbon ultra-low-silicon steel generally requires that the silicon content of its finished product is below 0.005%, that is, traces , it is obvious that the method of this patent cannot meet the requirement that the silicon content of the finished product of ultra-low carbon and ultra-low silicon steel is below 0.005%.

Method used

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  • Method for preventing silicon content from increasing during smelting of ultra-low-carbon and ultra-low-silicon steel
  • Method for preventing silicon content from increasing during smelting of ultra-low-carbon and ultra-low-silicon steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034]Desulfurization of molten iron: molten iron: S=0.002%, Ti+Nb+V=0.020%, strictly control residual elements Cu+Ni+Cr+Mo≤0.05% in steel.

[0035] Converter smelting: endpoint carbon 0.030%, O=0.070%. Tapping temperature: 1700°C; tapping without pre-deoxidation.

[0036] RH refining: Natural decarburization is adopted in RH, and the pressure in the furnace is kept below 100Pa. After the carbon is removed to 0.005%, the free oxygen in the steel is 350ppm. Add aluminum pellets for deoxidation, the free oxygen in the steel is 20ppm, and the aluminum content in the steel is 0.005%. And deoxidize the slag surface, the total iron + manganese oxide in the slag is 10%. Molten steel was quenched for 15 minutes and then continuously cast.

[0037] Continuous casting: the tundish is blown and baked for more than 3 hours, and the tundish is replaced with argon before continuous casting. The ladle nozzle is sealed with argon, and the tundish adopts an immersion nozzle to reduce the c...

Embodiment 2

[0039] Desulfurization of molten iron: molten iron: S=0.0018%, Ti+Nb+V=0.018%, strictly control residual elements Cu+Ni+Cr+Mo≤0.05% in steel.

[0040] Converter smelting: endpoint carbon 0.035%, O=0.065%. Tapping temperature: 1697°C; tapping without pre-deoxidation.

[0041] RH refining: Natural decarburization is adopted in RH, and the pressure in the furnace is kept below 100Pa. After the carbon is removed to 0.0048%, the free oxygen in the steel is 250ppm. Add aluminum pellets for deoxidation, the free oxygen in the steel is 18ppm, and the aluminum content in the steel is 0.0048%. And deoxidize the slag surface, the total iron + manganese oxide in the slag is 9%. Molten steel was quenched for 15 minutes and then continuously cast.

[0042] Continuous casting: the tundish is blown and baked for more than 3 hours, and the tundish is replaced with argon before continuous casting. The ladle nozzle is sealed with argon, and the tundish adopts an immersion nozzle to reduce th...

Embodiment 3

[0044] Desulfurization of molten iron: molten iron: S=0.0015%, Ti+Nb+V=0.015%, strictly control residual elements Cu+Ni+Cr+Mo≤0.05% in steel.

[0045] Converter smelting: endpoint carbon 0.040%, O=0.060%. Tapping temperature: 1694°C; tapping without pre-deoxidation.

[0046] RH refining: Natural decarburization is adopted in RH, and the pressure in the furnace is kept below 100Pa. After the carbon is removed to 0.0045%, the free oxygen in the steel is 150ppm. Add aluminum pellets for deoxidation, the free oxygen in the steel is 15ppm, and the aluminum content in the steel is 0.0045%. And deoxidize the slag surface, the total iron + manganese oxide in the slag is 8%. Molten steel was quenched for 15 minutes and then continuously cast.

[0047] Continuous casting: the tundish is blown and baked for more than 3 hours, and the tundish is replaced with argon before continuous casting. The ladle nozzle is sealed with argon, and the tundish adopts an immersion nozzle to reduce th...

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Abstract

The invention discloses a method for preventing an increase of a silicon content in a smelting process of ultra-low carbon ultra-low silicon steel. The method comprises the following steps: 1) molteniron desulfurization; 2) converter smelting: controlling the mass content of end-point carbon to be 0.030%-0.055%, controlling the mass content of oxygen to be 0.045%-0.070%, and controlling the masscontent of sulfur to be below 0.005%; 3) argon blowing; 4) RH refining: carrying out decarburization and deoxidation on molten steel, controlling the mass content of carbon in the molten steel to dropto 0.005% or below, controlling the mass content of free oxygen to be 20 ppm or below, controlling the mass content of aluminum to be 0.005% or below, and deoxidizing a slag surface; and 5) continuous casting: a control objective of a tundish temperature: controlling a liquidus temperature of the molten steel to be +20-35 DEG C, and controlling a mass content of free oxygen in a tundish to be 50ppm or below. The method can keep silicon in the molten steel in the smelting process to be traces until the continuous casting ends, thereby successfully solving the problem of silicon increasing inthe smelting process of the ultra-low carbon ultra-low silicon steel.

Description

technical field [0001] The invention relates to a production method of ultra-low-carbon and ultra-low-silicon steel, in particular to a method for preventing the increase of silicon content during the smelting process of ultra-low-carbon and ultra-low-silicon steel. Background technique [0002] Ultra-low-carbon ultra-low-silicon steel generally requires that the silicon content of its finished product is below 0.005%. After RH refining, pouring and other post-processes, if the control is not good, the silicon in molten steel will increase a lot. The composition of the steel is incompatible, which leads to the revision or cancellation of the sentence. [0003] Chinese invention patent "Silicon content control process for smelting low-silicon steel" (application number 201210180384.0), discloses a low-silicon variety steel to prevent silicon increase in the smelting process and stably control the silicon content at the end of molten steel. Temperature control, tapping deoxi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21C7/068C21C7/06C21C7/10C21C5/28C21C1/02
Inventor 帅习元黄静周勇鲁修宇仇东丽张帆张洪钢任安超
Owner 武汉钢铁有限公司
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