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AOD (Argon Oxygen Decarburization) secondary back-blowing decarburization method for ultra-low carbon steel smelting

A technology for ultra-low carbon steel and decarburization, which is applied in the field of AOD secondary blowback decarburization in ultra-low carbon steel smelting, and can solve the problems of excessive C content, poor quality of steel slag and high cost.

Active Publication Date: 2022-04-12
湖州盛特隆金属制品有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the added ferrosilicon generally contains about 15% carbon, and the single-slag process cannot remove the carbon contained in the added ferrosilicon. There is a problem of excessive C content in molten steel, and there is a certain hidden danger of C jumping. Cause back blowing or scrapping, the quality of tapping is unstable, and the quality of steel slag is poor, and the cost of aluminum used is high, and the addition of aluminum in sampling and calculation of alkalinity also causes trouble in calculation

Method used

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Embodiment

[0023] AOD secondary back blowing decarburization method for ultra-low carbon steel smelting, including EAF+AOD+LF+slab casting, in which EAF furnace smelting uses more than 70% of the returned material, and the tapping temperature is ≧1660°C, so that the molten steel Low carbon content, reduce the amount of subsequent ferrosilicon added.

[0024] In AOD furnace smelting, the following steps are included:

[0025] S1. Sampling: After the AOD furnace is mixed with steel, take samples to measure the temperature in the furnace, and remove slag to 200-300Kg; if the amount of steel slag is less than 200kg, there is no need to remove slag;

[0026] S2, AOD one-time decarburization:

[0027] a. The first stage of decarburization: add alloy smelting according to the target composition of the steel type, carry out decarburization by pure oxygen blowing, rapidly raise the temperature until the temperature of molten steel reaches 1680-1720°C, add primary reduced lime, and keep the alkal...

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Abstract

The invention discloses an AOD (Argon Oxygen Decarburization) secondary back-blowing decarburization method for ultra-low carbon steel smelting, which comprises the following steps of: adding an alloy for smelting according to target components of a steel grade, and carrying out pure oxygen blowing decarburization until the temperature of molten steel reaches 1680-1720 DEG C; the blowing gas ratio is adjusted to be 1: 4 for decarburization till the C content in the molten steel is smaller than or equal to 0.005%; 200-300 kg of ferrosilicon is reserved firstly, then the remaining ferrosilicon is added, and decarburization is conducted according to the blowing gas ratio of 1: 4 till the content of C in molten steel is smaller than or equal to 0.005%; 200-300 kg of reserved silicon iron is added, so that the content of C in the molten steel is smaller than or equal to 0.006%; the slag is drossing to 200 kg, then secondary slagging is carried out, 200-300 kg of special-grade reduced lime and fluorite are added till the steel slag is yellowish white, and secondary slag is formed. The method has the characteristics that the cost is reduced, the tapping quality stability is improved, and the calculation difficulty is reduced.

Description

technical field [0001] The invention relates to a method for smelting ultra-low carbon steel, in particular to an AOD secondary back-blowing decarburization method for smelting ultra-low carbon steel. Background technique [0002] At present, in the domestic stainless steel production process, for ultra-low carbon steel grades with C mass content ≤ 0.020%, such as: 904L, 926, etc., the AOD single slag method is usually used for decarburization smelting, that is, aluminum ingots are used after a decarburization treatment + Deoxidation and reduction in the form of ferrosilicon, so that the mass content of C in molten steel is ≤0.020%. However, the added ferrosilicon generally contains about 15% carbon, and the single-slag process cannot remove the carbon contained in the added ferrosilicon. There is a problem of excessive C content in molten steel, and there is a certain hidden danger of C jumping. Cause back blowing or scrapping, unstable tapping quality, and poor quality of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/068C21C7/06
CPCY02P10/20
Inventor 张光金宋利兵宋建宝杨新胜杨锟李花兵
Owner 湖州盛特隆金属制品有限公司