LF furnace cover capable of preventing nitrogen increase in refining process

Abstract

The utility model provides an LF furnace cover for preventing nitrogen increase in the refining process, which is characterized by comprising an LF furnace, the top of the LF furnace is provided with a furnace cover, the upper surface of the furnace cover is provided with a gas inlet main pipe of an annular structure, the gas inlet main pipe is connected with a plurality of gas inlet branch pipes, the gas inlet branch pipes penetrate into the LF furnace from the furnace cover, the furnace cover is provided with gas outlet holes, and the gas outlet holes are communicated with the gas inlet main pipe. An air outlet pipe is connected to the air outlet hole, a one-way valve and an exhaust valve are arranged on the air outlet pipe, the exhaust valve is connected with a controller, the controller is connected with an air pressure sensor used for detecting the air pressure in the LF furnace, and the air pressure sensor is arranged on the furnace cover. The plurality of air inlet branch pipes are arranged on the furnace cover, carbon dioxide is quickly sprayed to the surface of molten steel in the LF furnace through the plurality of nozzles, the molten steel is isolated from air, the molten steel is effectively prevented from being in contact with oxygen and nitrogen in the air in the refining process, the content of nitrogen and oxygen in the molten steel is increased, and the refining effect of the molten steel is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of LF furnace equipment and relates to a LF furnace cover which can prevent nitrogen from being added during a refining process. Background Art

[0002] Nitrogen is a harmful impurity for most steel grades. Excessive nitrogen content in steel will increase the aging of steel, causing undesirable phenomena such as blue brittleness, thereby reducing the plasticity, toughness, cold processing and other properties of steel. Nitrogen also generates irregular angular brittle inclusions with elements such as titanium and aluminum, causing quality problems such as macro segregation and loose structure of steel. In the LF furnace refining process, the liquid surface of molten steel is exposed to the air during the refining process, and the power-on time, deoxidizer, pressure regulation and other links in the LF refining process will affect the nitrogen addition of molten steel.

[0003] Relevant research shows that CO2 has weak oxidizing properties at high temperatures and can react with elements such as C, Si, and Mn in the molten pool at steelmaking temperatures. It can also be used as a stirring gas and protective gas instead of nitrogen and argon. In order to reduce the nitrogen content in the molten steel refining process, CO2 gas is used as a protective gas to prevent the molten steel from coming into contact with the air and absorbing nitrogen during the refining process. It can also prevent the molten steel from coming into contact with oxygen in the air, thereby reducing the oxygen content in the molten steel. Utility Model Content

[0004] The utility model aims to provide a LF furnace cover which can prevent nitrogen from increasing in the refining process, aiming at the problem that the nitrogen and oxygen contents in molten steel increase during LF furnace refining in the background technology.

[0005] To this end, the utility model adopts the following technical solutions:

[0006] A LF furnace cover for preventing nitrogen increase during a refining process comprises an LF furnace, a furnace cover is provided on the top of the LF furnace, an air intake main pipe in a ring structure is provided on the upper surface of the furnace cover, a plurality of air intake branch pipes are connected to the air intake main pipe, the air intake branch pipes penetrate into the LF furnace from the furnace cover, an air outlet is provided on the furnace cover, an air outlet is connected to the air outlet, a one-way valve and an exhaust valve are provided on the air outlet pipe, the exhaust valve is connected to a controller, the controller is connected to an air pressure sensor for detecting the air pressure in the LF furnace, and the air pressure sensor is arranged on the furnace cover.

[0007] Furthermore, the air intake main pipe is connected to a gas delivery pipe, the gas delivery pipe is connected to a gas storage tank for storing carbon dioxide gas, and a gas delivery valve is provided on the gas delivery pipe.

[0008] Furthermore, the gas delivery valve is connected to a controller.

[0009] Furthermore, a nozzle is provided at one end of the air intake branch pipe away from the air intake main pipe.

[0010] Furthermore, a plurality of electrode holes are provided on the furnace cover, and a refining electrode is provided in the motor hole.

[0011] The beneficial effects of the utility model are as follows: a plurality of air inlet branches are arranged on the furnace cover to quickly spray carbon dioxide onto the surface of molten steel in the LF furnace through a plurality of nozzles, thereby isolating the molten steel from the air, effectively preventing the molten steel from contacting with oxygen and nitrogen in the air during the refining process, increasing the nitrogen and oxygen content in the molten steel, and improving the refining effect of the molten steel; an air outlet pipe and a one-way valve are arranged to discharge the air in the LF furnace during the process of spraying carbon dioxide, thereby preventing air from accumulating in the LF furnace; the structure is simple and the method of use is convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic front view of the structure of the utility model;

[0013] Figure 2 It is a schematic top view of the structure of the utility model;

[0014] Figure 3 This is the control principle diagram of the utility model;

[0015] In the figure, 1-LF furnace, 2-furnace cover, 3-air inlet main pipe, 4-air inlet branch pipe, 5-nozzle, 6-gas delivery pipe, 7-gas storage tank, 8-gas delivery valve, 9-gas outlet, 10-gas outlet pipe, 11-check valve, 12-exhaust valve, 13-controller, 14-air pressure sensor, 15-electrode hole, 16-refining electrode. DETAILED DESCRIPTION

[0016] The utility model is described in detail below with reference to the accompanying drawings:

[0017] like Figure 1-3As shown, a LF furnace cover for preventing nitrogen addition during a refining process comprises an LF furnace 1, wherein the LF furnace 1 is an existing conventional LF furnace, wherein a furnace cover 2 is arranged on the top of the LF furnace 1, wherein an air intake main pipe 3 in an annular structure is arranged on the upper surface of the furnace cover 2, wherein a plurality of air intake branch pipes 4 are connected to the air intake main pipe 3, wherein the air intake branch pipes 4 penetrate into the LF furnace 1 from the furnace cover 2, wherein a nozzle 5 is arranged at one end of the air intake branch pipe 4 away from the air intake main pipe 3, wherein carbon dioxide gas can be sprayed into the upper surface of molten steel in the LF furnace 1 through the nozzle, so that the carbon dioxide is located above the surface of the molten steel in the LF furnace 1 as a protective gas, thereby effectively preventing nitrogen and oxygen in the air from contacting the molten steel, and wherein the air can be quickly isolated from the molten steel by spraying carbon dioxide gas to the LF furnace 1 simultaneously through the plurality of nozzles 5, wherein the air intake main pipe 3 is connected to a gas delivery pipe 6, wherein the gas delivery pipe 6 is connected to a storage device for storing carbon dioxide gas. The gas tank 7 and the gas pipe 6 are also provided with a gas valve 8. The carbon dioxide gas in the gas storage tank 7 is input into the air inlet main pipe 3 through the gas pipe 6, and finally the carbon dioxide gas is input into the LF furnace 1 through the air inlet branch pipe 4. The furnace cover 2 is provided with an air outlet hole 9, and the air outlet hole 9 is connected to an air outlet pipe 10. When the carbon dioxide gas is input into the LF furnace 1, the air in the LF furnace 1 can be discharged through the air outlet pipe 10. The air outlet pipe 10 is provided with a one-way valve 11 and an exhaust valve 12. The exhaust valve 12 is connected to a controller 13. The controller 13 can adopt an existing conventional PLC controller. The opening of the exhaust valve 12 can be controlled by the controller 13. The controller 13 is connected to an air pressure sensor 14 for detecting the air pressure in the LF furnace 1. The air pressure sensor 14 is arranged on the furnace cover 2. In addition, the gas valve 8 is also connected to the controller 13.

[0018] A plurality of electrode holes 15 are provided on the furnace cover 2. Refining electrodes 16 are provided in the electrode holes 15. The refining electrodes 16 can be conventional refining electrodes. The refining effect of molten steel can be improved by the refining electrodes 16.

[0019] The usage of the utility model is as follows:

[0020] When refining molten steel, argon gas is first blown from the bottom to stir the molten steel, and then the gas supply valve 8 and the exhaust valve 12 can be opened through the controller 13, and the carbon dioxide gas in the gas storage tank 7 is input into the air intake main pipe 3 through the gas supply pipe 6, and then the carbon dioxide gas enters multiple air intake branches 4 and is sprayed to the surface of the molten steel in the LF furnace 1 through the nozzle 5, so that the carbon dioxide gas quickly covers the surface of the molten steel, isolates the molten steel from the air, and effectively prevents the molten steel from contacting with nitrogen and oxygen in the air during the refining process, thereby increasing the nitrogen and oxygen content in the molten steel. In the process of spraying carbon dioxide gas into the LF furnace 1, the ventilation in the LF furnace 1 is discharged through the outlet pipe 10 to prevent air from accumulating in the LF furnace 1. After a period of carbon dioxide is sprayed, the exhaust valve 12 can be closed by the controller 13. As the carbon dioxide gas continues to be sprayed into the LF furnace 1, the gas pressure increases. When the air pressure sensor 14 detects that the air pressure reaches the set value, it sends a signal to the controller 13 to close the gas supply valve 8 and stop delivering carbon dioxide to the LF furnace 1.

[0021] The furnace cover can prevent the molten steel from contacting with air during the LF furnace refining process, effectively control the increase of nitrogen and oxygen content in the molten steel, and improve the refining quality.

Claims

1. A LF furnace cover for preventing nitrogen increase during refining process, characterized in that: The invention comprises an LF furnace (1), wherein a furnace cover (2) is provided on the top of the LF furnace (1), an air intake main pipe (3) in a ring-shaped structure is provided on the upper surface of the furnace cover (2), a plurality of air intake branch pipes (4) are connected to the air intake main pipe (3), the air intake branch pipes (4) penetrate into the LF furnace (1) from the furnace cover (2), an air outlet hole (9) is provided on the furnace cover (2), an air outlet pipe (10) is connected to the air outlet hole (9), a check valve (11) and an exhaust valve (12) are provided on the air outlet pipe (10), the exhaust valve (12) is connected to a controller (13), the controller (13) is connected to an air pressure sensor (14) for detecting the air pressure in the LF furnace (1), and the air pressure sensor (14) is arranged on the furnace cover (2).

2. The LF furnace cover for preventing nitrogen increase during the refining process according to claim 1, characterized in that: The air intake main pipe (3) is connected to an air delivery pipe (6), the air delivery pipe (6) is connected to a gas storage tank (7) for storing carbon dioxide gas, and a gas delivery valve (8) is provided on the air delivery pipe (6).

3. The LF furnace cover for preventing nitrogen increase during refining process according to claim 2, characterized in that: The gas delivery valve (8) is connected to a controller (13).

4. The LF furnace cover for preventing nitrogen increase during refining process according to claim 1, characterized in that: A nozzle (5) is provided at one end of the air intake branch pipe (4) away from the air intake main pipe (3).

5. The LF furnace cover for preventing nitrogen increase during refining process according to claim 1, characterized in that: The furnace cover (2) is provided with a plurality of electrode holes (15), and refining electrodes (16) are provided in the electrode holes (15).

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