Method for controlling nitrogen content of niobium-containing steel type

A control method and technology of nitrogen content, applied in the manufacture of converters, etc., can solve the problems of continuous casting slab hot charging and hot delivery, molten steel nitrogen absorption, large alloy amount, etc., to avoid excessive nitrogen content, improve heat delivery rate, The effect of reducing nitrogen addition

Inactive Publication Date: 2018-07-13
ANGANG STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

On the other hand, nitrogen can also cause cracking of billets
In actual production, due to the large amount of alloy in the tapping process of the converter, the influence of factors such as changes in the tap hole, bottom blowing, and end point control, the molten steel absorbs nitrogen, which brings difficulties to the refining process.
Many steel types that require nitrogen content have to be cleaned off-line due to high nitrogen content, which not only increases labor costs, but also cannot hot charge and deliver continuous casting slabs, which greatly increases energy consumption

Method used

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  • Method for controlling nitrogen content of niobium-containing steel type
  • Method for controlling nitrogen content of niobium-containing steel type
  • Method for controlling nitrogen content of niobium-containing steel type

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Effect test

Embodiment 1

[0036] Melting number 16BD1610, steel code A400LF, converter end point temperature 1687°C, oxygen value 658ppm, no supplementary oxygen blowing, converter end point comprehensive oxygen value 658ppm, argon blowing time for ladle before tapping is 2min, argon blowing flow rate is 80Nm 3 / h. Add 1.43 tons of alloy silicon-manganese, 2.29 tons of medium-carbon ferromanganese, and 0.2 tons of aluminum-manganese ferromanganese, and blow argon for 3 minutes when the tapping amount reaches one-third of the ladle, and the flow rate of argon blowing is 80Nm 3 / h. After tapping, the ladle was transported to the argon station for sampling and sent to the laboratory for testing. The nitrogen content in the molten steel was 19ppm.

Embodiment 2

[0038] Melting number 16CD1526, steel code L450M, converter end point temperature 1677°C, oxygen value 705ppm, supplemental oxygen blowing for 20 seconds, converter end point comprehensive oxygen value 905ppm, argon blowing time for ladle before tapping, 4min, argon blowing flow rate 80Nm 3 / h. Add 0.82 tons of alloy silicon manganese, 1.97 tons of medium carbon ferromanganese, and 0.17 tons of aluminum manganese ferromanganese, and blow argon for 2 minutes when the tapping amount reaches one third of the ladle, and the flow rate of argon blowing is 80Nm 3 / h. After tapping, the ladle was transported to the argon station for sampling and sent to the laboratory for testing. The nitrogen content in the molten steel was 23ppm.

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Abstract

The invention discloses a method for controlling the nitrogen content of a niobium-containing steel type. The method is characterized in that argon is blown into an empty steel ladle before tapping ofa converter, so that molten steel flow and the molten steel surface in the tapping process are always in the argon atmosphere; and the molten steel is isolated from air by the argon, so that absorption of the molten steel to nitrogen in air is reduced, and the content of the nitrogen in the molten steel is effectively controlled. Compared with the prior art, the method for controlling the nitrogen content of the niobium-containing steel type has the beneficial effects that the nitrogen increasing amount of the niobium-containing steel type in the converter tapping process is greatly reduced,pressure for treating the molten steel is relieved for the subsequent refining process, the nitrogen content in the molten steel is prevented from exceeding the standard, the corner crack of a continuous casting blank is reduced, the offline corner cleaning cost of the continuous casting blank is reduced, and the heat charging rate of the continuous casting blank is improved.

Description

technical field [0001] The invention relates to the technical field of alloy steel smelting technology, in particular to a method for controlling the nitrogen content of niobium-containing steel with high oxygen content at the end of the converter or after supplementary blowing at the end of the converter. Background technique [0002] With the development of industrial technology, the requirements for the purity of molten steel are getting higher and higher. Because the nitrogen content in steel affects its formability, welding performance, high temperature toughness and brittleness, it also increases the aging and brittleness of steel. On the other hand, nitrogen can also cause cracking of billets. In actual production, due to the large amount of alloy in the tapping process of the converter, the influence of factors such as changes in the tap hole, bottom blowing, and end point control, the molten steel absorbs nitrogen, which brings difficulties to the refining process....

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/072C21C5/30
Inventor 王小善何海龙高洪涛李泊李叶忠孙振宇朱国强李冰
Owner ANGANG STEEL CO LTD
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