A non-vacuum induction furnace top air blowing deoxidation device and method

Abstract

The present invention discloses a non-vacuum induction furnace top blowing deoxidation device and method, including: a gas source, including a methane gas source, an argon gas source and a compressed air gas source; a gas circuit, including a methane gas circuit connected to the methane gas source, an argon gas circuit connected to the argon gas source and a compressed air gas circuit connected to the compressed air gas source; a mixed gas bag connected to the methane gas circuit and the argon gas circuit; a top-blowing oxygen gun connected to the mixed gas bag through a conveying gas circuit to deoxidize the molten steel in the test furnace; a control cabinet to control the opening and closing of the gas circuit. The present invention achieves the purpose of deoxidation by blowing deoxidizing gas methane into the molten steel, solves the disadvantages of the existing deoxidation method, reduces the inclusion content in the steel, improves the quality of steel, improves the level of steelmaking logistics, and reduces the smelting cost per ton of steel.

Description

Technical Field

[0001] The present invention relates to a rapid deoxidation technology in the smelting process of an induction furnace in the metallurgical industry, and more particularly to an air blowing deoxidation device and method for a non-vacuum induction furnace top. Background Art

[0002] The traditional induction furnace smelting deoxidation method uses deoxidized alloy blocks (granules) and deoxidized alloy powder for precipitation deoxidation and diffusion deoxidation. Precipitation deoxidation is fast but has many inclusions, while diffusion deoxidation has fewer inclusions but is slow. The two deoxidation methods can no longer meet the increasingly high requirements for the comprehensive performance of steel, especially for steel inclusions. Therefore, seeking a deoxidation technology that can remove oxygen from molten steel without causing secondary pollution to the molten steel has always been the goal pursued by metallurgical workers. Summary of the Invention

[0003] In view of the above-mentioned defects existing in the prior art, the purpose of the present invention is to provide a non-vacuum induction furnace top blowing deoxidation device and method, which achieves the purpose of deoxidation by blowing deoxidizing gas methane into the molten steel, thereby solving the disadvantages of the existing deoxidation methods, reducing the inclusion content in the steel, improving the quality of steel, improving the level of steelmaking logistics, and reducing the smelting cost per ton of steel.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] In one aspect, a non-vacuum induction furnace top air blowing deoxidation device comprises:

[0006] Gas source, including methane gas source, argon gas source and compressed air gas source;

[0007] a gas circuit, comprising a methane gas circuit connected to the methane gas source, an argon gas circuit connected to the argon gas source, and a compressed air gas circuit connected to the compressed air gas source;

[0008] a mixed gas bag, connected to the methane gas path and the argon gas path;

[0009] A top-blowing oxygen lance, connected to the mixed gas bag through a conveying gas path, for deoxidizing the molten steel in the test furnace;

[0010] The methane gas circuit, argon gas circuit, compressed air gas circuit, and conveying gas circuit are respectively provided with a plurality of valves;

[0011] The control cabinet is used to control the opening and closing of multiple valves in the gas circuit so that the deoxidation rate of the top blowing deoxidation of the non-vacuum induction furnace is greater than 64%.

[0012] Preferably, the methane gas line is provided with a first ball valve, a first pressure gauge, a first check valve, a first shut-off valve, a first pressure transmitter, a first mass flow meter, a first flow regulating valve and a second check valve in sequence; and / or

[0013] The argon gas path is provided with a second ball valve, a second pressure gauge, a second shut-off valve, a second pressure transmitter, a second mass flow meter, a second flow regulating valve and a third check valve in sequence; and / or

[0014] The compressed air circuit is provided with an eighth ball valve, a third pressure gauge, a seventh shut-off valve, an eighth check valve, a ninth ball valve and a third anti-backfire valve in sequence; and / or

[0015] The gas delivery line is provided with a fifth ball valve, a fifth shut-off valve, a sixth check valve, a sixth shut-off valve, a sixth ball valve, a seventh check valve, a seventh ball valve and a second anti-backfire valve in sequence.

[0016] Preferably, the gas circuit further includes a cleaning and replacement gas circuit for connecting the argon gas circuit with the methane gas circuit, and connecting the delivery gas circuit with the test furnace, and using argon gas to clean and replace the gas remaining in the gas circuit.

[0017] Preferably, a third shut-off valve and a fourth check valve are sequentially provided on the cleaning and replacement gas path connecting the argon gas path and the methane gas path;

[0018] The cleaning and replacement gas path connecting the delivery gas path and the test furnace is provided with a fourth shut-off valve, a third ball valve, a fifth check valve, a fourth ball valve and a first anti-backfire valve in sequence.

[0019] Preferably, the test furnace is a non-vacuum induction furnace.

[0020] Preferably, the control cabinet is also connected to an alarm.

[0021] Preferably, the top-blowing oxygen lance includes a top lance body and a lifting mechanism connected thereto;

[0022] The top gun body is made of a non-magnetic stainless steel tube, and the outside of the tube is covered with corundum casting material.

[0023] On the other hand, a method for blowing and deoxidizing a non-vacuum induction furnace top of the blowing and deoxidizing device is provided, wherein the gas remaining in the gas path of the blowing and deoxidizing device of the non-vacuum induction furnace top is replaced. After the replacement is completed, all valves are closed in reverse order, the second shut-off valve on the argon gas path is kept open, the opening of the second flow regulating valve is adjusted, the test furnace is started, and the gas mixture ratio and pressure, and the blowing time are set.

[0024] The test furnace melts the raw materials, measures the temperature and oxygen, and adds oxygen with iron oxide according to the measured free oxygen content until the free oxygen content and temperature reach the required values ​​for the test. The temperature and oxygen are then kept, and the argon cover on the top of the test furnace is opened, and the top-blown oxygen lance is inserted to deoxidize the molten steel in the furnace.

[0025] Preferably, the gas supply intensity of the top-blown oxygen lance is 15-1000 L / t·min, and the gas pressure is 0.1-0.3 KPa;

[0026] The ratio of argon to methane is (0-100)% / (100-0)%.

[0027] The present invention provides a non-vacuum induction furnace top air blowing deoxidation device and method, which has the following beneficial effects:

[0028] 1) No need for metal deoxidizer, saving costs;

[0029] 2) Since the deoxidation product is gas, the inclusions in the steel are significantly reduced;

[0030] 3) The deoxidation efficiency is above 60%, and the cleanliness of the molten steel is stable and controllable;

[0031] 4) The ratio of methane and argon can be adjusted arbitrarily, and the gas volume can be adjusted in a wide range;

[0032] 5) Deoxidizing the molten steel can also reduce the oxidizing properties of the slag. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the overall framework of the air blowing deoxidation device of the present invention;

[0034] Figure 2 It is a schematic diagram of the framework of the air blowing deoxidation device of the present invention;

[0035] Figure 3 It is a structural schematic diagram of the top-blowing oxygen lance in the air-blowing deoxidation device of the present invention. DETAILED DESCRIPTION

[0036] In order to better understand the above technical solutions of the present invention, the technical solutions of the present invention are further described below with reference to the accompanying drawings and embodiments.

[0037] Combine Figure 1 and Figure 2 As shown, the present invention provides a non-vacuum induction furnace top air blowing deoxidation device, comprising:

[0038] Gas sources, including a methane gas source 1, an argon gas source 2, and a compressed air gas source 3;

[0039] The gas circuit includes a methane gas circuit connected to the methane gas source 1, an argon gas circuit connected to the argon gas source 2, and a compressed air gas circuit connected to the compressed air gas source 3;

[0040] The mixed gas bag 4 is connected to the methane gas path and the argon gas path;

[0041] The top-blowing oxygen lance 5 is connected to the mixed gas bag 4 through the conveying gas path and is used to deoxidize the molten steel in the test furnace;

[0042] Multiple valves are respectively provided on the methane gas line, argon gas line, compressed air gas line and conveying gas line;

[0043] The control cabinet 6 is used to control the opening and closing of multiple valves in the gas circuit so that the deoxidation rate of the non-vacuum induction furnace top blowing deoxidation is greater than 64%.

[0044] Methane is a hydrocarbon that cracks into carbon and hydrogen at high temperatures. These carbon and hydrogen react with oxygen in molten steel to produce carbon monoxide and water vapor. These gases can escape from the molten steel without contaminating it. Therefore, using methane to deoxidize molten steel is an effective method for producing clean, high-quality steel. Furthermore, methane deoxidation offers several advantages: first, the deoxidation products do not contaminate the molten steel, reducing inclusion content and improving steel quality; second, the cost of methane is significantly lower than that of the deoxidizing alloy, significantly reducing the cost per ton of deoxidized steel.

[0045] The methane gas line is provided with a first ball valve 7, a first pressure gauge 8, a first check valve 9, a first shut-off valve 10, a first pressure transmitter 11, a first mass flow meter 12, a first flow regulating valve 13 and a second check valve 14 in sequence.

[0046] The argon gas line is provided with a second ball valve 15 , a second pressure gauge 16 , a second shut-off valve 17 , a second pressure transmitter 18 , a second mass flow meter 19 , a second flow regulating valve 20 and a third check valve 21 in sequence.

[0047] The gas delivery line is provided with a fifth ball valve 29 , a fifth shut-off valve 30 , a sixth check valve 31 , a sixth shut-off valve 32 , a sixth ball valve 33 , a seventh check valve 34 , a seventh ball valve 35 and a second anti-backfire valve 36 in sequence.

[0048] The test furnace is a non-vacuum induction furnace 37.

[0049] The gas circuit also includes a cleaning and replacement gas circuit, which is used to connect the argon gas circuit with the methane gas circuit, and to connect the delivery gas circuit with the test furnace to prevent the oxygen in the air retained in the pipeline from interfering with the test structure and causing an explosion.

[0050] A third shut-off valve 22 and a fourth check valve 23 are provided in sequence on the purge replacement gas line connecting the argon gas line and the methane gas line;

[0051] A fourth shut-off valve 24 , a third ball valve 25 , a fifth check valve 26 , a fourth ball valve 27 and a first anti-backfire valve 28 are sequentially provided on the purge replacement gas line connecting the delivery gas line and the test furnace.

[0052] Taking into account the flammability of methane gas, the methane gas line was cleaned before the test. First, the methane gas source 1 was closed, and then the second ball valve 15, the second pressure gauge 16, the third shut-off valve 22, the fourth check valve 23, the first pressure transmitter 11, the first mass flow meter 12, the first flow regulating valve 13 and the second check valve 14 were opened to enter the mixed gas bag 4, and then connected to the bottom gas supply original of the vacuum induction furnace 38 through the fifth ball valve 29, the fifth shut-off valve 30, the sixth check valve 31, the fourth shut-off valve 24, the third ball valve 25, the fifth check valve 26, the fourth ball valve 27 and the first anti-backfire valve 28. After cleaning and replacement, the corresponding valves were closed to ensure that no air would remain in the pipeline.

[0053] Similarly, the argon gas line needs to be cleaned and replaced before the test. The operating steps are the same as those for cleaning the methane gas line.

[0054] The compressed air line is equipped with an eighth ball valve 39, a third pressure gauge 40, a seventh shut-off valve 41, an eighth check valve 42, a ninth ball valve 43, and a third anti-backfire valve 44, which are connected to the test furnace (the bottom air supply element of the vacuum induction furnace 38, or the bottom air supply element of the non-vacuum induction furnace 37). If the bottom air supply element becomes clogged during testing, the compressed air is used to blow it open.

[0055] The control cabinet 6 is also connected to three alarms 45 for detecting leakage of the methane gas line, the argon gas line and the compressed air gas line respectively. Once a gas leak occurs, the alarm 45 will sound an alarm.

[0056] Combine Figure 2 As shown, the top-blowing oxygen lance 5 includes a top lance body 501 and a lifting mechanism 502 connected thereto;

[0057] The top gun body 501 is made of a non-magnetic stainless steel tube, and is coated with a corundum casting material 502.

[0058] Non-magnetic stainless steel was chosen because the induction furnace heats the material through magnetic field induction. During the test, the top gun could not be heated to ensure the smooth flow of gas through the top gun. The purpose of the corundum castable is also to resist high temperatures.

[0059] The present invention also provides a method for blowing and deoxidizing a non-vacuum induction furnace top. After cleaning and replacing the non-vacuum induction furnace top using the blowing and deoxidizing device of the present invention, all valves are closed in reverse order, the second shut-off valve 17 on the argon gas path is kept open, the opening of the second flow regulating valve 20 is adjusted, the test furnace is started, and the temperature is increased by power. During the melting process, the opening of the second flow regulating valve 20 is adjusted at any time, oxygen is blown manually to assist melting, and the gas mixture ratio, pressure, and blowing time are set.

[0060] Entering preparation, the test furnace melts the raw materials, measures the temperature and oxygen, and uses iron oxide to add oxygen according to the measured free oxygen content until the free oxygen content and temperature reach the required values ​​for the test. Insulate the heat and oxygen, open the argon seal manual valve, maintain a slight positive pressure in the argon seal cover on the top of the test furnace, and insert the top-blown oxygen lance to deoxidize the molten steel in the furnace.

[0061] The gas supply intensity of the top-blown oxygen lance 5 is 15-1000 L / t·min, and the gas pressure is 0.1-0.3 KPa;

[0062] The ratio of argon to methane is (0-100)% / (100-0)%.

[0063] The results of the molten steel deoxidation test by injecting methane into the induction furnace are shown in Table 1.

[0064] Table 1

[0065]

[0066] Example 1

[0067] The free oxygen content is 734.45 ppm, the molten steel temperature is 1590°C, and the charge amount is 150 kg.

[0068] Perform a preliminary pipeline purge: Set the argon / methane ratio to 100 / 0, the pressure to 0.2 kPa, and the flow rate to 100 L / min. Open the furnace manual valve and press the purge button. After 2 minutes of purge, close the furnace manual valve and then turn off the purge button.

[0069] Load the furnace, install the argon hood, and power on to increase the temperature. Once a certain amount of molten pool has formed at the bottom, set the gas mixture ratio to 0:100 argon / methane, the flow rate to 5 L / min, the pressure to 0.15 kPa, and the injection time to 30 minutes. Press the "one-touch injection" button and slowly open the furnace manual valve, adjusting the opening according to the churning situation until it is fully opened. Once all the melt is clear, close the furnace manual valve and turn off the "one-touch injection" button. Measure the temperature and oxygen level, and adjust the temperature to 1590°C ± 10°C.

[0070] Set process parameters: argon and methane pressure: 0.2Kpa, mixed gas flow rate 13L / min, blowing time 8 minutes, the mixing ratio is dynamically adjusted during the blowing process, starting argon / methane 1 / 9, blowing for 3 minutes 3 / 7, blowing for 6 minutes 5 / 5, blowing for 7 minutes 7 / 3,

[0071] Press the one-button injection, slowly open the manual valve next to the furnace, and adjust the opening according to the tumbling situation until it is fully open. After the injection is completed, blow argon alone for 5 minutes.

[0072] Measure temperature, take samples and determine oxygen, adjust composition and temperature, tap steel, and finish.

[0073] Example 2

[0074] Free oxygen 520.4PPm, molten steel temperature 1608℃, charging amount 170kg.

[0075] Perform a preliminary pipeline purge: Set the argon / methane ratio to 100 / 0, the pressure to 0.2 kPa, and the flow rate to 100 L / min. Open the furnace manual valve and press the purge button. After 2 minutes of purge, close the furnace manual valve and then turn off the purge button.

[0076] Load the furnace, install the argon hood, and power on to increase the temperature. Once a certain amount of molten pool has formed at the bottom, set the gas mixture ratio to 0:100 argon / methane, the flow rate to 5 L / min, the pressure to 0.13 kPa, and the injection time to 30 minutes. Press the "one-touch injection" button and slowly open the furnace manual valve, adjusting the opening according to the churning situation until it is fully opened. Once all the melt is clear, close the furnace manual valve and turn off the "one-touch injection" button. Measure the temperature and adjust the oxygen level, adjusting the temperature to 1608°C ± 10°C.

[0077] Set process parameters: argon and methane pressure: 0.2Kpa, mixed gas flow rate 15L / min, blowing time 8 minutes, the mixing ratio is dynamically adjusted during the blowing process, starting argon / methane 1 / 9, blowing for 3 minutes 3 / 7, blowing for 6 minutes 5 / 5, blowing for 7 minutes 7 / 3,

[0078] Press the one-button injection, slowly open the manual valve next to the furnace, and adjust the opening according to the tumbling situation until it is fully open. After the injection is completed, blow argon alone for 5 minutes.

[0079] Measure temperature, take samples and determine oxygen, adjust composition and temperature, tap steel, and finish.

[0080] Example 3

[0081] Free oxygen 603.2PPm, molten steel temperature 1601℃, charging amount 200kg.

[0082] Perform a preliminary pipeline purge: Set the argon / methane ratio to 100 / 0, the pressure to 0.2 kPa, and the flow rate to 100 L / min. Open the furnace manual valve and press the purge button. After 2 minutes of purge, close the furnace manual valve and then turn off the purge button.

[0083] Load the furnace, install the argon hood, and power on to raise the temperature. Once a certain amount of molten pool has formed at the bottom, set the gas mixture ratio to 0:100 argon / methane, the flow rate to 5 L / min, the pressure to 0.15 kPa, and the injection time to 30 minutes. Press the "one-touch injection" button and slowly open the furnace manual valve, adjusting the opening according to the churning situation until it is fully opened. Once all the melt is clear, close the furnace manual valve and turn off the "one-touch injection" button. Measure the temperature and adjust the oxygen level, adjusting the temperature to 1601°C ± 10°C.

[0084] Set process parameters: argon and methane pressure: 0.2Kpa, mixed gas flow rate 16L / min, blowing time 8 minutes, the mixing ratio is dynamically adjusted during the blowing process, starting argon / methane 1 / 9, blowing for 3 minutes 3 / 7, blowing for 6 minutes 5 / 5, blowing for 7 minutes 7 / 3,

[0085] Press the one-button injection, slowly open the manual valve next to the furnace, and adjust the opening according to the tumbling situation until it is fully open. After the injection is completed, blow argon alone for 5 minutes.

[0086] Measure temperature, take samples and determine oxygen, adjust composition and temperature, tap steel, and finish.

[0087] The use of induction furnaces for metallurgical activities is very common. Due to the limitations of deoxidation technology, the quality of molten steel smelted in general induction furnaces is generally not high, which limits the improvement of induction furnace smelting technology and also limits the limitations of induction furnace smelting steel types. The present invention is conducive to improving induction furnace smelting technology, expanding induction furnace steelmaking varieties, and improving steelmaking quality. Therefore, this technical invention can be widely used in induction furnace smelting, and can also be extended to other smelting furnaces such as converters, electric furnaces, and refining furnaces.

[0088] Those skilled in the art should recognize that the above embodiments are merely intended to illustrate the present invention and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A non-vacuum induction furnace top blowing deoxidation device, characterized in that: include: Gas source, including methane gas source, argon gas source and compressed air gas source; a gas circuit, comprising a methane gas circuit connected to the methane gas source, an argon gas circuit connected to the argon gas source, and a compressed air gas circuit connected to the compressed air gas source; A mixed gas bag, connected to the methane gas circuit and the argon gas circuit; A top-blowing oxygen lance is connected to the mixed gas bag through a conveying gas path and is used to deoxidize the molten steel in the test furnace; The methane gas circuit, the argon gas circuit, the compressed air gas circuit, and the conveying gas circuit are respectively provided with a plurality of valves; A control cabinet is used to control the opening and closing of multiple valves in the gas circuit. The deoxidation rate of the non-vacuum induction furnace top blowing deoxidation is greater than 64%. The methane gas line is provided with a first ball valve, a first pressure gauge, a first check valve, a first cut-off valve, a first pressure transmitter, a first mass flow meter, a first flow regulating valve and a second check valve in sequence; The argon gas path is provided with a second ball valve, a second pressure gauge, a second cut-off valve, a second pressure transmitter, a second mass flow meter, a second flow regulating valve and a third check valve in sequence; The compressed air circuit is provided with an eighth ball valve, a third pressure gauge, a seventh shut-off valve, an eighth check valve, a ninth ball valve and a third anti-flashback valve in sequence. In the test, once the bottom air supply component is blocked, the bottom air supply component is blown open with compressed air; The gas delivery path is provided with a fifth ball valve, a fifth shut-off valve, a sixth check valve, a sixth shut-off valve, a sixth ball valve, a seventh check valve, a seventh ball valve and a second anti-flashback valve in sequence. The gas circuit also includes a cleaning and replacement gas circuit, which is used to connect the argon gas circuit with the methane gas circuit, and connect the delivery gas circuit with the test furnace, and use argon gas to clean and replace the gas remaining in the gas circuit. The cleaning and replacement gas path connecting the argon gas path and the methane gas path is provided with a third shut-off valve and a fourth check valve in sequence; The cleaning and replacement gas path connecting the delivery gas path and the test furnace is provided with a fourth shut-off valve, a third ball valve, a fifth check valve, a fourth ball valve and a first anti-flashback valve in sequence. The non-vacuum induction furnace top air blowing deoxidation device performs the following non-vacuum induction furnace top air blowing deoxidation method: The gas retained in the gas path of the air blowing deoxidation device on the top of the non-vacuum induction furnace is replaced. After the replacement is completed, all valves are reversely closed in sequence, the second shut-off valve on the argon gas path is kept open, the opening of the second flow regulating valve is adjusted, the test furnace is started, and the gas mixing ratio and pressure, and the air blowing time are set; The test furnace melts the raw materials, measures the temperature and determines the oxygen, and adds oxygen with iron oxide according to the measured free oxygen content until the free oxygen content and the temperature reach the required values ​​for the test, and then the temperature and oxygen are kept, and the argon cover on the top of the test furnace is opened, and the top-blown oxygen lance is inserted to deoxidize the molten steel in the furnace. The control cabinet is also connected to three alarms for detecting leakage of the methane gas circuit, the argon gas circuit and the compressed air gas circuit respectively. Once a gas leakage occurs, the alarm will sound an alarm.

2. The air blowing deoxidation device for the top of a non-vacuum induction furnace according to claim 1, characterized in that: The test furnace is a non-vacuum induction furnace.

3. The air blowing deoxidation device for the top of a non-vacuum induction furnace according to claim 1, characterized in that: The top-blowing oxygen lance comprises a top lance body and a lifting mechanism connected thereto; The top gun body is made of a non-magnetic stainless steel pipe, and the outside of the pipe is coated with corundum casting material.

4. A method for air blowing deoxidation of a non-vacuum induction furnace top used in the air blowing deoxidation device of the non-vacuum induction furnace top as claimed in any one of claims 1 to 3, characterized in that: The gas retained in the gas path of the air blowing deoxidation device on the top of the non-vacuum induction furnace is replaced. After the replacement is completed, all valves are reversely closed in sequence, the second shut-off valve on the argon gas path is kept open, the opening of the second flow regulating valve is adjusted, the test furnace is started, and the gas mixing ratio and pressure, and the air blowing time are set; The test furnace melts the raw materials, measures the temperature and determines the oxygen, and adds oxygen with iron oxide according to the measured free oxygen content until the free oxygen content and the temperature reach the required values ​​for the test, and then the temperature and oxygen are kept, and the argon cover on the top of the test furnace is opened, and the top-blown oxygen lance is inserted to deoxidize the molten steel in the furnace. The gas supply intensity of the top-blown oxygen lance is 15-1000L / (t•min), and the gas pressure is 0.1-0.3kPa; The ratio of argon / methane is (0~100)% / (100~0)%.

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