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Converter blowing method

A converter blowing and converter blowing technology, applied in the manufacture of converters, etc., can solve the problems of inability to dephosphorize and decarburize

Inactive Publication Date: 2019-07-23
NIPPON STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, in this method, it is necessary to reduce the P concentration of the molten iron to 0.05% by mass or less in advance through an additional dephosphorization treatment, and the dephosphorization and decarburization treatments cannot be performed through a series of blowing processes.

Method used

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  • Converter blowing method

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Embodiment

[0071] Next, examples of the present invention will be described, but the conditions in the examples are examples of conditions adopted for confirming the practicability and effects of the present invention, and the present invention is not limited to the examples of conditions. The present invention can employ various conditions as long as the object of the present invention is achieved without departing from the gist of the present invention.

[0072] (Example)

[0073] The molten iron whose Si concentration in the molten iron is reduced to 0.05% by mass by desiliconization treatment is charged into the top-bottom blown converter, and Fe containing 96% by mass is added to the upper part in an amount of 6.3kg / ton of molten iron 2 o 3 of iron ore. Then, with a flow rate of 2.5Nm 3 / min / ton of molten iron O 2 Gas together, with the top blowing speed of the CaO component in the mixed powder being 2.5kg / min / ton of molten iron, the top blowing of the CaO component and Fe 2 o ...

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Abstract

Molten steel with a C concentration of at least 0.3 mass% is produced by: charging molten pig iron with an Si concentration of 0.15 mass% or less and P concentration of at least 0.09 mass% in a bottom-blowing converter furnace; top-blowing a mixed powder, which has CaO powder and Fe2O3 powder with a mass ratio of CaO components to Fe2O3 components of 9:1-6:4 and comprises at least 95 mass% total of CaO, CaCO3, FeO and Fe2O3, together with oxygen gas having a flow rate of 1.5-3.0 Nm3 / min / ton of molten pig iron; during the top-blowing, making the top-blown amount of CaO components in the mixed powder to be 10-15 kg / ton of the molten pig iron and the CaO component feed rate to be 1.5-3.0 kg / min / ton of molten pig iron; completing the top-blowing of the mixed powder while the C concentration in the molten pig iron is at least 2.5 mass%; and after completion of the top-blowing of the mixed powder, continuing the top-blowing of the oxygen gas.

Description

technical field [0001] The invention relates to a converter blowing method, which uses a small amount of slag to dephosphorize molten iron with a low Si concentration by using a top-bottom blown converter, and uses a series of blowing blows from the molten iron without discharging the slag generated by dephosphorization. The low-phosphorus steel with high C concentration is smelted in the form of smelting. Background technique [0002] In recent years, demand for steel with a high C concentration and a low P concentration has increased, and it is desired to mass-produce molten steel with such a composition using a converter. However, even if the molten iron is oxidized by top blowing oxygen to generate FeO in the slag, when the C concentration in the molten iron is high, FeO is easily reduced by the C in the molten iron. Therefore, while the C concentration in the molten iron in the blowing process is high, the FeO concentration in the slag shifts to a low value, and the de...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21C1/02C21C5/34C21C5/36C21C5/28
CPCC21C1/02C21C5/28C21C5/34C21C5/36C21C1/025
Inventor 宫田政树笠原秀平
Owner NIPPON STEEL CORP