Method for prevention of nitrogen increase in molten steel during steel tapping from a converter

A technology of tapping process and converter, applied in the direction of manufacturing converters, etc., can solve problems such as no relevant reports, and achieve the effect of reducing nitrogen increase in molten steel

Inactive Publication Date: 2012-07-11
ANGANG STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] So far, there have been no relevant reports on the contro

Method used

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  • Method for prevention of nitrogen increase in molten steel during steel tapping from a converter
  • Method for prevention of nitrogen increase in molten steel during steel tapping from a converter

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] A 180-ton converter is used to produce IF steel with a nitrogen upper limit of 0.005%, and the diameter of the ladle is 3.852m and the height is 4.915m. Two stages of argon blowing before tapping and after tapping are adopted. The specific process parameters and effects of each furnace are shown in Table 1:

[0024] Table 1 Specific process parameters and effect table of the two-stage argon blowing method before tapping and after tapping

[0025]

Embodiment 2

[0027] A 180-ton converter is used to produce IF steel with a nitrogen upper limit of 0.005%, and the diameter of the ladle is 3.852m and the height is 4.915m. Continuous and uninterrupted blowing of argon before and after tapping is adopted until the end of tapping. The specific process parameters and effects of each furnace are shown in Table 2:

[0028] Table 2 Specific process parameters and effect table of uninterrupted argon blowing before and after tapping

[0029]

[0030] The heat nitrogen increasing result that does not adopt the inventive method in the same period is as shown in table 3:

[0031] Table 3 does not adopt the furnace time nitrogen increasing result table of the inventive method

[0032] Stoves

[0033] As can be seen from the comparison of tapping nitrogen increasing amount in the above list table, the nitrogen increasing amount of molten steel after adopting the inventive method to tap has only 1.2ppm on average, but the heat nitrogen i...

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Abstract

The invention provides a method for prevention of nitrogen increase in molten steel during steel tapping from a converter, which comprises the steps of controlling the argon blowing time and argon flow before and during steel tapping from the converter, and blowing argon to the steel ladle in two segments or uninterruptedly till the finish of steel tapping. Thereafter, air in the steel ladle can be evacuated by the argon blown in to prevent the molten steel in the ladle contacting with air while tapping and to keep the molten steel in the ladle under the protection of argon all the time, which not only prevents molten steel contacting with air to cause nitrogen increase, but also removes the nitrogen [N] that can easily adsorb on the surface of the bubbles from the molten steel with the float and discharge of nitrogen bubbles. The method of the invention is simple and easy to implement and operate, and can remarkably reduce the possibility of nitrogen increase in the molten steel during tapping, so that the nitrogen increase in the molten steel can be controlled below 3ppm after tapping.

Description

technical field [0001] The invention belongs to the technical field of steelmaking technology, and in particular relates to a method for preventing molten steel from increasing nitrogen during the tapping process of a converter by blowing argon gas into a ladle. Background technique [0002] Ultra-low carbon and low nitrogen interstitial atom-free steel (IF steel) for automobiles and low nitrogen non-oriented silicon steel are generally smelted into molten steel in a converter after molten iron smelted in a blast furnace, and then heated in a RH (vacuum circulation degassing furnace) The degassing device performs secondary treatment on the molten steel, and then pours it into billets through the continuous casting machine. The whole smelting process mainly depends on the decarburization reaction in the converter for denitrification, and low nitrogen molten steel below 20ppm can be obtained. However, due to the nitrogen increase in the molten steel during the tapping process...

Claims

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Application Information

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IPC IPC(8): C21C5/28C21C5/46C21C7/072
Inventor 孙群李伟东王成青于守巍王荣
Owner ANGANG STEEL CO LTD
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