Method for controlling nitrogen content of molten steel in converter steel-making

A converter steelmaking and molten steel technology, applied in the manufacture of converters, etc., can solve the problems of difficult control of nitrogen addition and reduction of nitrogen absorption

Inactive Publication Date: 2014-09-17
PANGANG GRP PANZHIHUA STEEL & VANADIUM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

For the refining process of LF furnace, the amount of nitrogen absorption can be reduced by making foam slag and submerged arc operation; in the continuous casting process, the amount of nitrogen absorption can be reduced by adding a cover, sealing the nozzle with argon gas, and adopting an intrusive long nozzle; only converter tapping The amount of nitrogen increase in the process is not easy to control

Method used

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  • Method for controlling nitrogen content of molten steel in converter steel-making
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Examples

Experimental program
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Effect test

Embodiment 1

[0027] Production of DTLA steel. First, open the bottom of the ladle to blow argon before tapping. Then, add Al-Fe alloy deoxidizer (the weight of molten steel is 130t) in the ladle in the process of tapping, so that the oxygen content of molten steel after tapping remains on about 150ppm, thereby prevents molten steel from contacting nitrogen with air. Finally, deoxidize the molten steel in the ladle by feeding the aluminum wire (diameter of the aluminum wire is 10mm) at the wire feeding station so that the molten steel reaches the required oxygen content for pouring. The technological parameters of this process and the amount of nitrogen added in the tapping process are shown in Table 1 and Table 2.

Embodiment 2～9

[0031] The process flow of Examples 2-9 is the same as that of Example 1, and see Table 1 and Table 2 for the process parameters and the amount of nitrogen added in the tapping process. Wherein, the oxygen content of the tapped molten steel of the low alloy steel is kept at about 150 ppm, and the oxygen content of the tapped molten steel of the high alloy steel is kept at about 50 ppm.

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Abstract

The invention discloses a method for controlling nitrogen content of molten steel in converter steel-making. The method comprises the following steps: smelting molten iron into molten steel by using a converter; opening a steel ladle and performing bottom argon blowing before tapping; and in the tapping process, determining the quantity of a deoxidant added into the steel ladle according to the oxygen content of the molten steel in the converter so as to ensure that the oxygen content of the molten steel after tapping is more than 50ppm, thus preventing the molten steel from contacting air to absorb nitrogen. According to the method for controlling the nitrogen content of the molten steel in converter steel-making disclosed by the invention, the quantity of the deoxidant added into the steel ladle is determined according to the oxygen content of the molten steel in the converter so as to ensure that the oxygen content of the molten steel after tapping is more than 50ppm, namely that, the converter is not subjected to complete deoxidation in the tapping process so as to ensure that oxygen in the molten steel occupies the surface of the molten steel, and prevent the molten steel from contacting the air to absorb nitrogen, thus controlling the nitrogen increasing amount of the molten steel, for example, by adopting the method disclosed by the invention, the nitrogen increasing amount of the molten steel can be controlled within 0.0008%.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy, and in particular relates to a method for controlling the nitrogen content of molten steel in the converter steelmaking process. Background technique [0002] With the development of industry and technology, various industries have increasingly stringent requirements on the quality of steel. The nitrogen content in steel has a great influence on the mechanical properties of steel. When molten steel solidifies, the precipitation of gaseous nitrogen dissolved in steel will cause segregation of elements or cause pores in steel castings, which will reduce the performance of steel. The nitrogen content in the steel increases, the yield limit, strength limit and hardness increase, but the plasticity and impact toughness decrease, and it also causes age hardening. Nitrogen will also greatly increase the ductile-brittle transition temperature of steel, and may also cause low-temperatu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C5/34C21C7/06
Inventor 李盛雷辉聂绍刚
Owner PANGANG GRP PANZHIHUA STEEL & VANADIUM
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