Control method for preventing nitrogen increasing in LF refining treatment

A control method and technology before treatment, which are applied in the field of LF furnace refining process, can solve the problems of inability to submerged arc heating, improper atmosphere control, and neglect of furnace cover atmosphere.

Inactive Publication Date: 2015-08-19
BAOSHAN IRON & STEEL CO LTD
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Problems solved by technology

[0005] 1) Situation of slag material: add appropriate amount of lime, appropriate amount of high alumina deoxidizer, the speed of slag is slow
[0006] 2) Power supply system: When the LF furnace is heated, high voltage is used, the arc is long, and the noise is large
[0007] 3) The atmosphere in the furnace cover is not considered, and the opening of the dust removal valve is random
[0012] 1. The thickness of the slag layer on the top of the molten steel is not enough

Method used

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  • Control method for preventing nitrogen increasing in LF refining treatment
  • Control method for preventing nitrogen increasing in LF refining treatment

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Embodiment Construction

[0038] The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0039] see figure 1 Shown, the control method that prevents nitrogen increase in the LF furnace refining treatment of the present invention mainly comprises the following steps:

[0040] A. Submerged arc heating is implemented by replenishing slag before refining treatment. That is to say, when the molten steel is not electrified, it is first necessary to add a batch of slag to cover the molten steel.

[0041] This is because the slag blocking operation has been carried out during the tapping process of the converter, and the slag volume of the converter is controlled below 50mm. Since the molten steel is not in contact with the atmosphere, the thermodynamic and kinetic conditions for the nitrogen absorption of the molten steel are insufficient, and the slag can prevent Nitrogen absorption by molten steel. If molten steel en...

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Abstract

The invention discloses a control method for preventing nitrogen increasing in LF refining treatment. The control method comprises: before refining, performing submerged-arc heating via replenishing slag materials; in an initial stage of refining, producing white slag via ladle bottom high-flow-argon blowing, and adopting a low-current and low-voltage power supply; in an intermediate stage of refining, adopting a high-current and high-voltage power supply, and reducing frequency of heating and frequency of opening a furnace door for temperature measurement and sampling in order to improve the temperature raising efficiency; and in a later stage of refining, adopting ladle bottom small-flow-argon blowing, and the low-current and low-voltage power supply. The control method adopts the ways above for preventing nitrogen increasing, so that nitrogen increasing of an LF during a working process is effectively prevented; the average amount of nitrogen increasing is controlled in a range of 3-5ppm; and the quality of molten steel is further improved.

Description

technical field [0001] The invention relates to an LF furnace refining process, in particular to a control method for preventing nitrogen increase in the LF furnace refining process. Background technique [0002] Nitrogen in steel is a harmful element for most steel products. High nitrogen content in steel can easily lead to aging and blue brittleness of steel; when nitrogen exceeds a certain content, it will also cause slab bubbles and loose center; in addition, nitrogen also reduces the toughness, plasticity and welding performance of steel. Since nitrogen is the main substance in the air, it is easily inhaled by molten steel during steelmaking and difficult to remove by conventional methods. Therefore, it is particularly important to prevent nitrogen increase in the various processes of steelmaking. [0003] The ladle refining furnace (hereinafter referred to as LF furnace) adopts the bottom blowing argon stirring process in the process of processing molten steel. In th...

Claims

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Application Information

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IPC IPC(8): C21C7/00
Inventor 陆国弟张胜军
Owner BAOSHAN IRON & STEEL CO LTD
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