Control method for free oxygen in ultralow-carbon and low-aluminum steel

A control method and low-aluminum steel technology, applied in the direction of manufacturing converters, etc., can solve the problems of large fluctuation of free oxygen, excessive oxide inclusions, and difficulty in meeting process control requirements.

Active Publication Date: 2018-12-14
ANGANG STEEL CO LTD
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Problems solved by technology

The disadvantage of the above process is that due to boiling tapping, the top slag is highly oxidizable, the oxygen in the atmosphere is transferred to the molten steel, and the free oxygen fluctuates greatly. If the free oxygen is too high, it will lead to poor safety during pouring, and if the free oxygen is too low, it will cause oxides in the steel. The inclusions exceed the standard, and it is difficult to meet the process control requirements

Method used

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Embodiment Construction

[0013] A method for controlling free oxygen in ultra-low-carbon and low-aluminum steel according to the present invention, the production process of the ultra-low-carbon and low-aluminum steel is molten iron pretreatment, converter smelting, RH furnace vacuum refining, continuous casting; Powder desulfurization, converter boiling tapping and top slag modification, RH refining to complete decarburization and deoxidation, the final weight percentage of free oxygen in molten steel is controlled at 0.002% to 0.005%, and the weight percentage of Als is ≤0.003%; the specific steps are as follows:

[0014] Hot metal pretreatment: spray desulfurization powder into the hot metal, and clean the slag, when the weight percentage of sulfur in the hot metal is ≤0.003%, transfer the hot metal to the converter for smelting;

[0015] Converter smelting: Put the desulfurized molten iron into the converter, blow oxygen to reduce carbon and smelt it into molten steel, the oxygen blowing time is 15...

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Abstract

The invention relates to a control method for free oxygen in ultralow-carbon and low-aluminum steel. The ultralow-carbon and low-aluminum steel production technology includes molten iron pretreatment,converter smelting, RH furnace vacuum refining and continuous casting. Powder spraying desulfuration is adopted in molten iron pretreatment, converter boiling and tapping are conducted, top slag modification is conducted, RH refining is conducted, decarburization and deoxygenation are finished, the weight percent of the free oxygen in the steel is finally controlled to range from 0.002% to 0.005%, and the weight percent of Als is smaller than or equal to 0.003%. By means of the control method, safety production of a continuous casting machine can be achieved, a casting blank is free of defects in quality, and the continuous casting furnace number is three or more.

Description

technical field [0001] The invention relates to the technical field of iron and steel smelting, in particular to a method for controlling free oxygen in ultra-low carbon and low aluminum steel. Background technique [0002] Total oxygen in molten steel includes free oxygen dissolved in steel and oxygen present in oxide inclusions. At the end of converter smelting, the oxides in molten steel tend to be zero, and the total oxygen is mainly free oxygen. After the molten steel is completely sedated, the weight percentage of free oxygen in the molten steel is lower than 0.001%, and the total oxygen is mainly oxygen in oxides. [0003] The lower the content of elements other than Fe in the billet, the higher the purity of the steel. For some special-purpose steels, it is necessary to remove impurity elements in the steel as much as possible, such as the weight percentage of carbon in the steel is less than 0.003%, and the less oxide inclusions, the better. Before the molten ste...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C1/02C21C5/28C21C5/36C21C7/10C21C7/06C21C7/068
CPCC21C1/02C21C5/28C21C5/36C21C7/06C21C7/068C21C7/10
Inventor 吕志勇于海岐王金辉刘博张立夫邢维义
Owner ANGANG STEEL CO LTD
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