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A production method, ultra-low carbon steel technology, applied in the manufacture of converters, etc., can solve the problems of secondary pollution of molten steel, poor reforming effect, high oxygen content, etc., and achieve energy saving, temperature drop reduction, and oxygen blowing temperature rise Effect of Ratio
Inactive Publication Date: 2012-10-10
ANGANG STEEL CO LTD
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However, there are certain disadvantages in doing so, such as modification after vacuum refining, which will cause the oxidation of molten steel after refining; Reaction occurs, resulting in poor reformation effect
And if it is not modified, the highly oxidizable top slag will cause secondary pollution to the molten steel during the pouring process
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Embodiment 1
[0017] 1. Molten iron pretreatment: desulfurization by spraying method, and slag removal after desulfurization to ensure the effect of slag removal. Control the sulfur content in the hot metal after desulfurization, and control the mass percentage content of [S] at 0.0025%.
[0018] 2. Converter smelting: 260-ton top-bottom double-blown converter is used, first adding scrap steel and then adding molten iron;
[0019] The oxygen blowing time of converter smelting is controlled at 22 minutes, and the smelting cycle is 40 minutes;
[0020] During the smelting process, argon gas is blown at the bottom during the whole process, and the gas supply intensity is 0.05m 3 / min t;
[0021] The top-blown oxygen lance adopts a high-low-low gun position change operation system;
[0022] Control the quality of the fly ash that goes into the slag of the converter so that the S≤0.05 wt% in the fly ash that goes into the slag;
[0023] The mass percentage content of [C] at the end point of ...
Embodiment 2
[0028] 1. Molten iron pretreatment: desulfurization by spraying method, and slag removal after desulfurization to ensure the effect of slag removal. Control the sulfur content in the hot metal after desulfurization, and control the mass percentage content of [S] at 0.004%.
[0029] 2. Converter smelting: 260-ton top-bottom double-blown converter is used, first adding scrap steel and then adding molten iron;
[0030] The oxygen blowing time of converter smelting is controlled at 19 minutes, and the smelting cycle is 42 minutes;
[0031] During the smelting process, argon gas is blown at the bottom during the whole process, and the gas supply intensity is 0.07m 3 / min t;
[0032] The top-blown oxygen lance adopts a high-low-low gun position change operation system;
[0033] Control the quality of the fly ash that goes into the slag of the converter so that the S≤0.05 wt% in the fly ash that goes into the slag;
[0034] The mass percentage content of [C] at the end point of t...
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Abstract
The invention provides a production method of an ultra low carbon steel. The method comprises the steps of: employing a blowing process for desulfurization and slag removal of molten iron, with control of oxygen blowing time and smelting cycle of a converter, argon bottom-blowing in the whole course, and control of S content in slag lime, [C] content at converter end point, and temperature and oxygen activity at the endpoint, adding lime in a tapping process, and modifying ladle top slag after tapping; employing natural decarburization to control carbon content in an RH, wherein Als in molten steel is less than 0.03% after deoxidation, carrying out vacuum-breaking, adding aluminum powder and top slag modifier into the top slag, blowing argon with stirring, vacuumizing again, and carrying out clean circulation for 2-10 min; and carrying out continuous casting with protective casting in the whole course, wherein a nitrogen increase amount in the molten steel is controlled at less than 2 ppm. The invention can effectively reduce temperature drop in a transmission process, reduce oxygen blowing heating rate in a subsequent RH refining treatment, save energy and shorten the time of refining. Besides, the method can effectively guarantee modification effect of the top slag, prevent nozzle clogging and realize sequence casting. Therefore, the method is particularly applicable to the production of high purity ultra low carbon steel.
Description
technical field [0001] The invention belongs to the technical field of smelting technology, and in particular relates to a production method of ultra-low carbon steel. Background technique [0002] Ultra-low carbon steel refers to steel with a carbon content below 0.01%. Carbon is the traditional and most economical strengthening element. Carbon in steel increases the strength of steel through solid solution strengthening. However, with the increase of carbon content in the steel, the ductility and deep drawing performance of the rolled steel plate will be greatly reduced. With the development of industrial demand, the ultra-low carbon microalloying composition design system is adopted accordingly, which not only meets the requirements of steel strength performance, but also meets other requirements. [0003] At present, the smelting of ultra-low carbon steel mostly adopts the process route of converter smelting-RH (vacuum circulating degassing furnace) vacuum treatment-co...
Claims
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