RH vacuum furnace efficient steelmaking method based on multi-mode cooperative control

Abstract

The invention discloses an efficient steelmaking method for an RH vacuum furnace based on multi-mode cooperative control. The efficient steelmaking method specifically comprises the steps that S1, baking parameters are optimized, gunning management is enhanced, and the service life of an insert pipe is prolonged; s2, vacuum chamber masonry quality acceptance standards are perfected, and the service life of refractory materials is prolonged; s3, optimizing the slag flowing mode of the vacuum furnace: changing the slag flowing mode from an oxygen and coal gas mode to an oxygen blowing oxidation mode by using a coal oxygen, pure oxygen and coal oxygen mode; nitrogen protection and air exhaust dust removal functions are added in the oxygen blowing and slag flowing process, so that potential safety hazards and environmental pollution caused by oxygen blowing are prevented; s4, scheduling the waiting time of the compression vacuum furnace to improve the production efficiency of the vacuum furnace; s5, a flexible matching method that steam jet pump-electric water ring pump vacuum system integration is adopted, and an electric water ring pump is used for replacing a last-stage steam jet pump is adopted; the service life of the refractory material is obviously prolonged, the service life of the insert pipe is averagely prolonged by 5.8 times / set, the steam and muddy water consumption is greatly reduced, and the steam consumption is reduced by 25kg / t.

Description

Technical Field

[0001] The present invention relates to the technical field of metallurgical processes, and in particular to an efficient steelmaking method for an RH vacuum furnace based on multi-mode collaborative control. Background Art

[0002] The RH vacuum refining technology can improve the quality of molten steel, reduce production costs, and expand product varieties in steel production, and is an important means to optimize the process flow. The RH vacuum furnace is the most functional and complex in various refining devices. The RH vacuum furnace has been widely used in the production of high-strength and ultra-clean steel, and is currently widely used in major steel plants. The application and practice of the high-efficiency production management of the vacuum furnace in long-process steel enterprises stem from the increasing market competition, resource and environmental problems, technological innovation, and the need for sustainable development. As a key link in steel production, the vacuum furnace can directly affect the operation efficiency and product quality of the entire production line through high-efficiency management. Driven by technological progress and management innovation, the high-efficiency production of the vacuum furnace has received strong support. The application of advanced control systems and automation technologies has realized the precise control and intelligent management of the vacuum furnace production process, improving the controllability and stability of the production process. The existing technologies have the following pain points: 1. The short service life of the immersion tube affects the control of the production rhythm.

[0003] 2. Slag draining is required every 25 - 30 productions, and the long slag draining time affects production organization.

[0004] 3. For steel grades with a relatively long continuous casting cycle, the vacuum waiting time during the furnace gap is long, resulting in low production efficiency.

[0005] 4. When converting from a steam jet pump to a water ring pump + steam pump mode to save steam and the amount of turbid circulating water, the vacuum pumping capacity needs to be improved. Summary of the Invention

[0006] The purpose of the present invention is to provide an efficient steelmaking method for an RH vacuum furnace based on multi-mode collaborative control in view of the above situation. Using this method for steelmaking in an RH vacuum furnace can effectively improve the steelmaking efficiency.

[0007] The specific solution of the present invention is: An efficient steelmaking method for an RH vacuum furnace based on multi-mode collaborative control specifically includes: S1. Optimize the baking parameters and strengthen the gunning management to improve the service life of the immersion tube: S1.1 Baking standards and parameter optimization. When the repaired vacuum tank is moved to the baking position for production, first conduct an inspection and confirmation. Check the metal argon gas pipe, metal cooling air pipe, and metal argon gas hose to ensure there are no burn marks, air leakage, or blockages. After connecting the argon gas pipe and the cooling air pipe, wrap the metal argon gas hose with a refractory fiber blanket and tie it firmly with wire. When starting the ignition baking, for the first time, adjust the flame length to 1 meter and bake for 24 hours until the temperature rises to 500 degrees. Subsequently, conduct the second adjustment, adjust the flame length to 1.2 meters, and continue baking for 24 hours to raise the temperature to 700 degrees. Then, conduct the third adjustment, adjust the flame length to 1.5 meters, and continue baking for 24 hours to raise the temperature from 700 degrees to 900 degrees. After that, maintain the baking state to keep the temperature in the tank at 850 - 900 degrees until starting production. The above steps ensure that the vacuum tank is baked according to standardized operations in the baking position for production and meets the required temperature requirements. S1.2 Spraying repair standards optimization for the insertion pipe. When conducting spraying repair and maintenance, focus on the eroded parts and give priority to spraying repair. During internal spraying, lift the spraying gun to the eroded part of the insertion pipe and slowly lower it to the joint of the two pipes. The spraying gun needs to rotate and spray evenly, from top to bottom, with each layer as thin and continuous as possible. The spraying operation should be carried out in a hot state, spraying while baking. The spraying material needs to have good adhesion. When conducting external spraying on the riser pipe, it is necessary to notify the vacuum operation room in advance to reduce the argon gas volume and spray layer by layer while rotating. For parts with material collapse or severe erosion, the spraying gun head can be removed first for spraying, and then reinstall the spraying gun head after the sprayed material is flush with the surrounding material. When there are local erosions such as pits in the outer casting material of the insertion pipe, complete spraying must be carried out to maintain the tubular shape and avoid excessive spraying on the outer pipe and insufficient spraying on the inner pipe, which may affect the circulation. The spraying work should be carried out step by step until the pipe shape maintenance meets the requirements. When the refractory materials on the inner and outer layers of the insertion pipe and the circulation pipe become thinner or have cracks, spraying repair and maintenance should be carried out in a timely manner. In the initial stage of using the insertion pipe, pay attention to the spraying repair of the joint between the lower end of the insertion pipe and the brick and the surface cracks. In the later stage of using the insertion pipe, focus on the spraying repair and maintenance of the outer casting material of the insertion pipe and outside the slag line to ensure that the on-line maintenance work of the insertion pipe meets the production standards. S1.3 Inspect and accept the quality of the gunning operation of the injection pipe. Adjust the supply of air, water, and materials according to the instructions of the gunning operator. When adjusting at the start of gunning, adjust the air, water, and materials to the optimal state in sequence. When shutting down the top gunning, perform the withdrawal operation in the sequence of materials, water, and air. When changing sides or switching between internal and external gunning, stop the supply of materials first, then lower the gun and start the turntable, and at the same time perform the moving operation of the gunning vehicle. During the gunning process, the areas such as pits, cracks, and peeling must be repaired completely, and at the same time, prevent the phenomenon of excessive thickening or diameter reduction of the injection pipe. After the gunning is completed, lower the spray gun to position 0, switch the spray gun bucket to the designated side, perform the operation of closing the materials in the sequence of top gunning, close the water source after half a minute, and then close the air source after another half a minute. Remove the air and water pipes and hang them in the designated positions, and drive the gunning vehicle back to the standby position. Fill the empty hopper with gunning materials, and finally perform the work of cleaning up and leaving the site. All the above operations comply with the production standards to ensure the smooth progress of the gunning work; S2. Improve the quality acceptance standard of the vacuum chamber masonry to extend the service life of refractories: S2.1 The acceptance personnel inspect each part of the vacuum chamber, including the inspection of the bottom tank bottom and the large wall masonry, the inspection of the connection and welding of the injection pipe, the inspection of the baking situation at the baking position, the inspection before moving the chamber, the inspection of the gunning maintenance during the production process and the confirmation of the removal of the vacuum chamber when it is taken offline; S2.2 Basic principles for inspecting and accepting the quality of the vacuum chamber masonry. When using magnesia-chrome bricks for the working layer wall bricks, dry-laying method should be used for masonry, but in necessary cases, brine magnesia-chrome fire clay can be appropriately used for leveling. When masonry the working layer, the requirement for the brick joints is not to exceed 1 mm, and it is strictly prohibited to use mortar to cover the brick joints. Before starting the masonry, it is necessary to unpack the refractory materials and inspect the appearance quality of the materials. The masonry of the bottom working layer should be pre-masoned. To ensure the masonry quality, the brick joints must be staggered. The lower tank overhaul closing door is installed on the east side, and there are certain allowable deviations in the dimensions of the electrofused re-bonded magnesia-chrome bricks, and they need to meet the appearance requirements; S2.3 Inspect and accept the quality of the lining masonry. Connect the injection pipe that has been completed with casting, demolding, curing, and baking to the bottom, lift and place the injection pipe on the injection pipe replacement trolley, ensure that the center line of the injection pipe is aligned with the central axis of the circulation pipe structure of the vacuum bottom tank body, and use bolts for fastening. After alignment, lower the lifting vehicle, evenly spread materials on the injection pipe, and lift again for docking, keep the injection pipe flange and the bottom circulation pipe flange horizontally fitted, and perform welding. Select appropriate welding wires and electrodes for welding to make the weld smooth and full, ensure that the internal weld is full and free of pores. Install a circular seal on the injection pipe and the bottom circulation pipe flange, and use appropriate welding wires and electrodes for welding again to make the weld smooth and full, and complete the masonry work at the bottom; S3. Optimize the slag flow pattern of the vacuum furnace: Use the all-oxygen slagging method: change the slagging mode from the oxygen + gas mode to the oxygen blowing oxidation mode, and use the method of coal-oxygen + pure oxygen + coal-oxygen; during the oxygen blowing slagging process, add nitrogen protection and exhaust gas dust removal functions to prevent potential safety hazards and environmental pollution caused by oxygen blowing; S4. Schedule the waiting time of the compression vacuum furnace to improve the production efficiency of the vacuum furnace. According to the furnace-machine matching principle, adopt the following production scheduling mode: for steel grades with relatively fast drawing speeds, the vacuum furnace uses a double-station docking casting machine, which can save auxiliary time and improve production efficiency; for some steel grades with relatively slow drawing speeds, control the production rhythm, and the vacuum furnace uses the production mode of double-station to double casting machines to improve production efficiency; for the time of changing the casting ladle of the casting machine, also control the production rhythm and do a good job in reconnecting the double-station of the vacuum to the double casting machines, which can meet the seamless connection production mode and increase the daily output by 2-3 furnaces of steel; S5. Adopt the integration of a steam jet pump - electric liquid ring pump vacuum system and use a flexible matching method of replacing the last-stage steam jet pump with an electric liquid ring pump.

[0008] Furthermore, in step S2.3 of the present invention, welding wires and electrodes of 506 or 507 are selected for welding.

[0009] Furthermore, in step S1.2 of the present invention, the water mixing ratio principle of the gunning mix is as follows: when cracks appear inside and outside, the material should be slightly thinner; when potholes appear inside and outside, the material should be slightly thicker; when local caving occurs, the material should be in a porridge state.

[0010] The present invention has the following technical advantages compared with the prior art: 1. The refractory life is significantly improved, and the average life of the immersion tube is increased by 5.8 times per set.

[0011] 2. The application of the present invention greatly reduces the consumption of steam and turbid water, and the steam consumption decreases by 25 kg / t.

[0012] 3. The application of the present invention saves the consumption of gas and oxygen, and the annual savings of gas and oxygen consumption are at least about 100,000 yuan or more.

[0013] 4. The application of the present invention increases the operation rate of the vacuum furnace by more than 30%. Specific embodiments

[0014] The technical solutions of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0015] The present invention is a high-efficiency steelmaking method for an RH vacuum furnace based on multi-mode collaborative control, which specifically includes: S1. Optimize baking parameters and strengthen gunning management to improve the service life of the immersion tube: S1.1 Baking standard and parameter optimization. When the repaired vacuum tank is moved to the baking position for production, first conduct an inspection and confirmation. Check the metal argon gas pipe, metal cooling air pipe, and metal argon gas hose to ensure there are no burn marks, air leakage, or blockage; after connecting the argon gas pipe and the cooling air pipe, wrap the metal argon gas hose with refractory fiber blanket and tie it firmly with iron wire; when starting the ignition baking, adjust the flame length to 1 meter for the first time, bake for 24 hours until the temperature rises to 500 degrees, then conduct the second adjustment, adjust the flame length to 1.2 meters, continue baking for 24 hours to make the temperature rise to 700 degrees, then conduct the third adjustment, adjust the flame length to 1.5 meters, continue baking for 24 hours to make the temperature rise from 700 degrees to 900 degrees, and then maintain the baking state to keep the temperature in the tank at 850 - 900 degrees until starting production; the above steps ensure that the vacuum tank is baked according to the standardized operation in the baking position for production and reaches the required temperature requirements; S1.2 Optimization of the gunning standard for the immersion tube. When conducting gunning maintenance, focus on the eroded parts and give priority to gunning repair; during internal gunning, lift the gunning gun to the eroded part of the immersion tube and slowly lower it to the joint of the two tubes. The gunning gun needs to rotate and be sprayed evenly from top to bottom, with each layer as thin and continuous as possible; the gunning operation should be carried out in the hot state, and at the same time, bake while gunning. The gunning material needs to have good adhesion. When conducting external gunning on the riser tube, it is necessary to notify the vacuum operation room in advance to reduce the argon gas volume and spray and rotate layer by layer; for the parts with material collapse or severe erosion, the gunning gun head can be removed first for gunning, and then install the gunning gun head after the gunning is flush with the surrounding material; when there are local erosions such as pits in the outer casting material of the immersion tube, complete gunning must be carried out to maintain the tubular shape and avoid excessive external tube gunning and insufficient internal tube gunning, which may affect the circulation; the gunning work should be carried out step by step until the tube shape maintenance meets the requirements; when the refractory materials on the inner and outer layers of the immersion tube and the circulation tube are thinned or cracked, gunning maintenance should be carried out in a timely manner; in the initial stage of using the immersion tube, pay attention to the gunning repair of the joint between the lower end of the immersion tube and the brick and the surface cracks; in the later stage of using the immersion tube, focus on the gunning maintenance of the outer casting material around the immersion tube and outside the slag line to ensure that the on-line maintenance work of the immersion tube meets the production standards; further, the water ratio principle of the gunning material in step S1.2 of the present invention is: when there are cracks inside and outside, the material should be slightly thinner; when there are pits inside and outside, the material should be slightly thicker; when there is local material collapse, the material should be in a porridge state; S1.3 Inspect and accept the quality of the injection pipe gunning operation. Adjust the supply of air, water, and materials according to the instructions of the gunning operator. When adjusting at the start of gunning, adjust air, water, and materials to the optimal state in sequence. When shutting down the top gunning, perform the withdrawal operation in the sequence of materials, water, and air. When changing sides or switching between internal and external gunning, first stop the supply of materials, then lower the gun and start the turntable, and at the same time perform the moving operation of the gunning vehicle. During the gunning process, it is necessary to completely repair areas such as pits, cracks, and peeling, and at the same time prevent the phenomenon of excessive thickening or diameter reduction of the injection pipe. After the gunning is completed, lower the spray gun to position 0, switch the spray gun bucket to the designated side, and perform the operation of closing the materials in the sequence of top gunning. After half a minute, turn off the water source, and after another half a minute, turn off the air source. Remove the air and water pipes and hang them at the designated positions, and drive the gunning vehicle back to the standby position. Fill the empty hopper with gunning materials, and finally perform the work of cleaning up and leaving the site. All the above operations comply with the production standards to ensure the smooth progress of the gunning work. Strengthen gunning management, including gunning quality, gunning plan, selection of gunning materials, and technical training, etc. Good gunning quality can improve the service life of the injection pipe in the vacuum chamber, meet the needs of continuous production, and achieve more efficient production organization.

[0016] S2. Improve the quality acceptance standard of vacuum chamber masonry to increase the service life of refractories: S2.1 The acceptance personnel inspect each part of the vacuum chamber, including the inspection of the lower tank bottom and the masonry of the large wall, the inspection of the connection and welding of the injection pipe, the inspection of the baking situation at the baking position, the inspection before moving the chamber, the inspection of the gunning maintenance during the production process and the confirmation of the removal of the vacuum chamber when it is taken offline; S2.2 Basic principles for inspecting and accepting the quality of vacuum chamber masonry. When using magnesia-chrome bricks for the wall bricks of the working layer, dry masonry method should be used for masonry, but in necessary cases, brine magnesia-chrome fire clay can be appropriately used for leveling. When masonry the working layer, the requirement for brick joints is not to exceed 1mm, and it is strictly prohibited to use mortar to cover the brick joints. Before starting masonry, it is necessary to unpack the refractory materials and inspect the appearance quality of the materials. The masonry of the bottom working layer should be pre-masoned. To ensure the masonry quality, the brick joints must be staggered. The lower tank overhaul closing door is installed on the east side, and there are certain allowable deviations in the dimensions of the electrofused re-bonded magnesia-chrome bricks, and they need to meet the appearance requirements. The specific dimensional deviations are shown in the following table:

[0017] S2.3 Quality inspection and acceptance of the inner lining masonry. Connect the inserted pipe that has completed pouring, demolding, curing, and baking to the bottom. Lift and place the inserted pipe on the inserted pipe replacement trolley, ensuring that the center line of the inserted pipe is aligned with the central axis of the circulating pipe structure of the vacuum bottom trough body. Fasten it with bolts. After alignment, lower the lifting trolley, evenly spread materials on the inserted pipe, and lift it again for docking, keeping the flange of the inserted pipe and the flange of the bottom circulating pipe horizontally fitted, and then perform welding. Select appropriate welding wires and electrodes for welding to make the weld smooth and full, ensuring that the inner weld is full and free of pores. Install a circular seal on the flanges of the inserted pipe and the bottom circulating pipe, and use appropriate welding wires and electrodes for welding again to make the weld smooth and full, completing the masonry work at the bottom. Further, in step S2.3 of the present invention, welding wires and electrodes of 506 or 507 are selected for welding; S3. Optimize the slag flowing mode of the vacuum furnace: During the vacuum pumping process, some slag in the ladle enters the vacuum chamber along with the molten steel. After the treatment is completed, the molten steel flows into the ladle, while some slag accumulates on the inner wall of the vacuum chamber. The slag has a high oxygen content and reacts with the carbon and oxygen in the molten steel during the next vacuum pumping. In a vacuum environment, the molten slag is in an emulsified foam state and splashes under the drive of CO gas, seriously blocking the alloy feeding port, camera hole, and oxygen lance hole in the vacuum chamber, affecting the production stability. At the same time, after the vacuum treatment for a period of time, slag accumulates at the hot bend pipe part at the top of the vacuum chamber, which is the vacuum pumping channel, blocking the flue gas channel, resulting in poor vacuum pumping effect and significantly affecting some steel grades that require dehydrogenation. To ensure the smooth progress of production, the slag on the inner wall of the vacuum chamber and the hot bend pipe part at the top of the vacuum chamber must be removed in a timely manner.

[0018] The existing slag flowing mode is to adjust the coal-oxygen ratio of MFB to 1:2, and use the treatment interval for oxygen-enriched baking in the vacuum chamber to quickly remove the residual steel and residue in the vacuum chamber. The molten slag is in a liquid state and flows out from the lower opening of the inserted pipe. At the same time, the oxygen lance can move freely up and down in the vacuum chamber to effectively remove the residue throughout the vacuum chamber. Generally, the slag flowing frequency is once every 25 furnaces of steel production, and the slag flowing time for each time is preferably controlled within 60 minutes.

[0019] If the vacuum furnace wants to produce efficiently, the slag flowing also becomes a restricting factor. After repeatedly debugging various slag flowing modes, changing the coal-oxygen ratio, adjusting the height of the top lance, etc., no good results have been obtained. Finally, the full-oxygen slag flowing method is innovatively used: Change the slag flowing mode from the oxygen + coal gas mode to the oxygen blowing oxidation mode, using the method of coal oxygen + pure oxygen + coal oxygen; during the oxygen blowing slag flowing process, add nitrogen protection and exhaust gas dust removal functions to prevent safety hazards and environmental pollution caused by oxygen blowing; through this mode change, the effect is obvious. The slag flowing time is controlled within 45 minutes, and the refractory life is not affected, and the environment is also improved accordingly. The cold steel in the vacuum chamber is reduced, the slag flowing time is shortened, the slag flowing burden during offline is reduced, and at the same time, in order to achieve better vacuum treatment effect.

[0020] S4. Schedule the waiting time of the compression vacuum furnace to improve the production efficiency of the vacuum furnace. According to the furnace-machine matching principle, make the following production scheduling modes: for steel grades with faster casting speeds, the vacuum furnace uses a double-station docking casting machine, which can save auxiliary time and improve production efficiency; for some steel grades with slower casting speeds, control the production rhythm, and the vacuum furnace uses the production mode of double-station to double casting machines to improve production efficiency; for the time of changing ladles of the casting machine, also control the production rhythm and do a good job in the reconnection of the vacuum double-station to double casting machines, then the seamless connection production mode can be satisfied, and the daily output can be increased by 2 - 3 furnaces of steel. S5. Adopt the integration of a steam jet pump - electric liquid ring pump vacuum system, and use the flexible matching method of replacing the last-stage steam jet pump with an electric liquid ring pump.

[0021] Traditional RH vacuum furnaces mostly use steam jet pumps as vacuum acquisition equipment, which have problems such as large steam consumption and difficult balance of workshop steam. With the rise of energy costs and the improvement of environmental protection requirements, it has become an inevitable trend to find more energy-saving and efficient alternative solutions. As a new type of vacuum pump technology, the electric liquid ring pump has become a new type of vacuum pump to replace the traditional steam jet pump. The electric liquid ring pump mainly relies on the motor to drive the impeller to rotate, has a small starting resistance, and does not require long-term preheating. Its motor power consumption is relatively stable. Taking an actual production scenario application as an example, the motor power is about 380 kilowatts during normal operation. Converted into energy consumption, it is far lower than the steam energy consumption of the steam pump. The power consumption of the electric liquid ring pump mainly depends on factors such as the pump model, impeller speed, and the amount of gas to be processed. By reasonably selecting the model and optimizing the operation parameters, the power consumption can be further reduced. The integrated optimization technology of the steam jet pump - electric liquid ring pump vacuum system has been developed, and the flexible matching theoretical calculation method of replacing the last-stage steam jet pump with an electric liquid ring pump has been proposed, realizing a reduction of more than 20% in the peak steam flow rate, a reduction of more than 25% in the steam consumption per ton of steel, and a reduction of more than 10 kg in the carbon dioxide emissions per ton of steel.

[0022] When our company's RH vacuum furnace uses a steam jet pump, the steam energy consumption is about 125.16 kg / t of molten steel. After the transformation and adoption of an electric liquid ring pump, the energy consumption mainly consists of the electricity cost of the liquid ring pump motor (calculated according to the local electricity price) and a small amount of auxiliary losses, with a total of 92.14 kg / t of molten steel. Through comparison, it can be clearly seen that after the electric liquid ring pump replaces the steam jet pump, the energy consumption is significantly reduced by 33.02 kg / t. The steam cost of the vacuum furnace is 80 yuan per ton, the electric liquid ring pump consumes 190 kilowatts of electricity per hour, and the electricity price is 0.88 yuan per degree. When using the steam jet pump, the steam consumption per furnace of steel is 18.7 tons, and after using the liquid ring pump, the steam consumption per furnace of steel is 12.9 tons. It can be concluded that the steam consumption per furnace of steel is reduced by 5.8 tons, which is equivalent to saving 464 yuan per furnace of steam. The electric liquid ring pump consumes 167.2 yuan of electricity per hour, and 296.8 yuan is saved per furnace of steel.

[0023] The following is a calculation based on the statistics of a certain month: Before using the electric liquid ring pump

[0024] After using the electric liquid ring pump

[0025] The total steam consumption for the whole month of this month is 95 kg / t, including the standby steam energy consumption such as standby when the molten steel enters the station.

Claims

1. An efficient steelmaking method for RH vacuum furnace based on multi-mode collaborative control, characterized in that, Specifically, it includes: S1. Optimize baking parameters and strengthen gunning management to improve the service life of the dip tube: S1.1 Baking standard and parameter optimization. When the repaired vacuum tank is moved to the baking position for production, first check and confirm. Check the metal argon gas pipe, metal cooling air pipe, and metal argon gas hose to ensure there are no burnt marks, air leakage, or blockages. After connecting the argon gas pipe and the cooling air pipe, wrap the metal argon gas hose with a refractory fiber blanket and tie it firmly with wire. When starting the ignition baking, adjust the flame length to 1 meter for the first time and bake for 24 hours until the temperature rises to 500 degrees. Then, make the second adjustment, adjust the flame length to 1.2 meters, and continue baking for 24 hours to raise the temperature to 700 degrees. Make the third adjustment, adjust the flame length to 1.5 meters, and continue baking for 24 hours to raise the temperature from 700 degrees to 900 degrees. After that, maintain the baking state and keep the temperature in the tank at 850 - 900 degrees until starting production. The above steps ensure that the vacuum tank is baked according to standardized operations in the baking position for production and meets the required temperature requirements. S1.2 Optimization of the gunning standard for the dip tube. When performing gunning maintenance, focus on the eroded parts and give priority to gunning repair. During internal gunning, lift the gunning gun to the eroded part of the dip tube and slowly lower it to the joint of the two tubes. The gunning gun needs to rotate and spray evenly from top to bottom, with each layer as thin and continuous as possible. The gunning operation should be carried out in the hot state, and at the same time, bake and gun while the gunning material needs to have good adhesion. When performing external gunning on the riser tube, it is necessary to notify the vacuum operation room in advance to reduce the argon gas volume and gun layer by layer while rotating. For parts with material collapse or severe erosion, the gunning gun head can be removed first for gunning, and then reinstall the gunning gun head after the gunning is flush with the surrounding material. When there are local erosions such as pits on the outer casting material of the dip tube, complete gunning must be carried out to maintain the tubular shape and avoid excessive external gunning of the outer tube and insufficient internal gunning of the inner tube, which may affect the circulation. The gunning work should be carried out step by step until the tube shape maintenance meets the requirements. When the refractory materials on the inner and outer layers of the dip tube and the circulation tube are thinned or cracked, gunning maintenance should be carried out in a timely manner. In the initial stage of using the dip tube, pay attention to the gunning repair of the joint between the lower end of the dip tube and the brick and the surface cracks. In the later stage of using the dip tube, focus on the gunning maintenance of the outer casting material around the dip tube and outside the slag line to ensure that the on-line maintenance work of the dip tube meets the production standards. S1.3 Insertion tube gunning operation quality inspection and acceptance. Adjust the supply of air, water, and materials according to the instructions of the gunning operator. When adjusting at the start of gunning, adjust air, water, and materials to the optimal state in sequence. When shutting down the top gunning, perform the withdrawal operation in the sequence of materials, water, and air. When changing sides or switching between internal and external gunning, stop the supply of materials first, then lower the gun and start the turntable, and at the same time perform the movement operation of the gunning vehicle. During the gunning process, the areas such as pits, cracks, and peeling must be completely repaired, and at the same time, prevent the phenomenon of excessive thickening or diameter reduction of the insertion tube. After the gunning is completed, lower the spray gun to position 0, switch the spray gun bucket to the designated side, and perform the operation of closing the materials in the sequence of top gunning. Turn off the water source after half a minute, and then turn off the air source after another half a minute. Remove the air and water pipes and hang them in the designated position, and drive the gunning vehicle back to the standby position. Fill the empty hopper with gunning materials, and finally perform the work of cleaning up and leaving the site. All the above operations comply with the production standards to ensure the smooth progress of the gunning work. S2. Improve the quality acceptance standard of vacuum chamber masonry to extend the service life of refractories: S2.1 The acceptance personnel check each part of the vacuum chamber, including the inspection of the lower tank bottom and the large wall masonry, the inspection of the connection and welding of the insertion tube, the inspection of the baking situation at the baking position, the inspection before moving the chamber, the inspection of the gunning maintenance during the production process and the confirmation of the removal of the vacuum chamber when it is taken offline. S2.2 Basic principles for the quality inspection and acceptance of vacuum chamber masonry. When using magnesia-chrome bricks for the working layer wall bricks, dry masonry method should be used for masonry, but in necessary cases, brine magnesia-chrome fire clay can be appropriately used for leveling. When masonry the working layer, the requirement for the brick joints is not to exceed 1 mm, and it is strictly prohibited to use mortar to cover the brick joints. Before starting the masonry, it is necessary to unpack the refractory materials and inspect the appearance quality of the materials. The masonry of the bottom working layer should be pre-masoned. To ensure the masonry quality, the brick joints must be staggered. The lower tank overhaul door is installed on the east side. There are certain allowable deviations in the dimensions of the electrofused re-bonded magnesia-chrome bricks, and they need to meet the appearance requirements. S2.3 Quality inspection and acceptance of the lining masonry. Connect the insertion tube that has been completed with pouring, demoulding, curing, and baking to the bottom. Lift and place the insertion tube on the insertion tube replacement trolley, ensure that the center line of the insertion tube is aligned with the central axis of the circulation pipe structure of the vacuum bottom tank body, and use bolts for fastening. After alignment, lower the lifting vehicle, evenly spread materials on the insertion tube, and lift again for docking, keep the insertion tube flange and the bottom circulation pipe flange horizontally fitted, and perform welding. Select appropriate welding wires and electrodes for welding to make the weld smooth and full, ensure that the internal weld is full and without pores. Install a ring-shaped seal on the insertion tube and the bottom circulation pipe flange, and use appropriate welding wires and electrodes for welding again to make the weld smooth and full, and complete the masonry work at the bottom. S3. Optimize the slag flowing mode of the vacuum furnace: Use the all-oxygen slag flowing method: Change the slag flowing mode from the oxygen + gas mode to the oxygen blowing oxidation mode, and use the method of coal oxygen + pure oxygen + coal oxygen. Add nitrogen protection and gas extraction and dust removal functions during the oxygen blowing slag flowing process to prevent potential safety hazards and environmental pollution caused by oxygen blowing. S4. Scheduling and compressing the waiting time of the vacuum furnace to improve the production efficiency of the vacuum furnace. According to the furnace-machine matching principle, the following production scheduling modes are adopted: for steel grades with relatively fast drawing speeds, the vacuum furnace uses a double-station docking casting machine, which can save auxiliary time and improve production efficiency; for some steel grades with relatively slow drawing speeds, control the production rhythm, and the vacuum furnace uses a double-station to double-casting machine production mode to improve production efficiency; for the time of changing the casting ladle of the casting machine, also control the production rhythm and do a good job in reconnecting the vacuum double-station to the double-casting machine, which can meet the seamless connection production mode, and the daily output can be increased by 2-3 furnaces of steel. S5. Adopt the integration of a steam jet pump - electric liquid ring pump vacuum system and use a flexible matching method of replacing the last-stage steam jet pump with an electric liquid ring pump.

2. The high-efficiency steelmaking method of an RH vacuum furnace based on multi-mode collaborative control according to claim 1, characterized in that, In step S2.3, welding wires and electrodes of 506 or 507 are selected for welding.

3. A high-efficiency steelmaking method for an RH vacuum furnace based on multi-mode collaborative control according to claim 1, characterized in that, In step S1.2, the water ratio principle of the gunning mix is as follows: when cracks appear inside and outside, the mix should be slightly thinner; when potholes appear inside and outside, the mix should be slightly thicker; when local caving occurs, the mix should be in a porridge state.

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