A method and system for rh vacuum gas solid injection pollution-free deoxidizing smelting high-performance steel

Abstract

The application provides a RH vacuum gas solid injection non-pollution deoxidization smelting high-performance steel method and system, and relates to the metallurgical technical field. The method comprises the following steps: determining the initial oxygen content, initial carbon content and steel liquid quality of the steel liquid at the RH station; dividing n pre-deoxidization stages, calculating the total mass of the required carbon deoxidizer, the mass of the carbon deoxidizer in each stage, the end vacuum degree of the kth stage and the injection rate of each stage; starting the RH, starting the injection of the flowable carbon deoxidizer into the steel liquid according to the vacuum degree p to pre-deoxidize, and adjusting the flow of the carrier gas to meet m 总 , m k and v k ; after the injection is completed and the composition of the steel liquid is stable, the actual oxygen content of the steel liquid is measured, and whether the conditions for entering the formal deoxidization period are met is judged according to the actual oxygen content. The method provided by the application can efficiently pre-deoxidize, improve the de-nitrogen environment, promote composition homogenization, reduce aluminum consumption and improve the cleanliness of the molten steel.

Description

Technical Field

[0001] This application relates to the field of metallurgical technology, and in particular to a method and system for pollution-free deoxidation smelting of high-performance steel using RH vacuum solid injection. Background Technology

[0002] RH refining is a key process in steelmaking to improve the cleanliness of molten steel. Its typical process includes vacuuming, decarburization, deoxidation, alloying, vacuum breaking, and calcium feeding. The decarburization stage aims to reduce the carbon content of the molten steel to a target value, primarily achieved through natural vacuum decarburization or forced oxygen blowing. However, towards the end of the decarburization stage, to ensure the carbon content ([C]) in the molten steel is reduced to the target level, there is often an excessively high dissolved oxygen ([O]) content. In the subsequent deoxidation process, a large number of aluminum balls are usually added for precipitation deoxidation, which not only affects inclusion control but also increases production costs.

[0003] Finding a way to add carbonaceous deoxidizers without pollution under high vacuum, and effectively reduce the dissolved oxygen content in molten steel before the deoxidation process, is of great significance for steel plants to reduce costs and increase efficiency. Summary of the Invention

[0004] The purpose of this application is to provide a method and system for pollution-free deoxidation smelting of high-performance steel using RH vacuum solid-liquid injection, in order to solve the above-mentioned problems.

[0005] To achieve the above objectives, this application adopts the following technical solution: A method for pollution-free deoxidation smelting of high-performance steel using RH vacuum air-solid injection includes: Determine the initial oxygen content (O) of the molten steel at the RH station. 到站 Initial carbon content C 到站 and the mass of molten steel m 钢液 Divide the process into n pre-deoxidation stages, and calculate the total mass m of the required carbonaceous deoxidizer using Formula 1. 总 Then, using Formula 2, the mass m of the carbonaceous deoxidizer in the kth stage of the n pre-deoxidation stages is calculated. k The final vacuum degree P of the kth stage is calculated using Formula 3. 结束 Then, the carbonaceous deoxidizer injection rate v for each stage is calculated using Formula 4. k ; RH is started, and the carrier gas is injected into the molten steel to pre-deoxidize the fluidized carbonaceous deoxidizer, while controlling the flow rate of the carrier gas and the vacuum degree P. 结束 To satisfy the m 总 The m k and the v k ; After the blowing process is completed and the composition of the molten steel stabilizes, measure the actual oxygen content (O) of the molten steel. 实际According to the actual oxygen content O 实际 Determine whether the conditions for entering the formal deoxidation period are met; if not, repeat the injection of the fluidized carbonaceous deoxidizer until the conditions for entering the formal deoxidation period are met. Formula 1 is: ; Formula 2 is: ; Formula 3 is: ; Formula 4 is: ; Where, m 总 The total mass of the required carbonaceous deoxidizer is expressed in kg; O 到站 The initial oxygen content of molten steel, in ppm; C 到站 The initial carbon content of the molten steel, in ppm; O 目标 Oxygen content in the target steel grade, in ppm; C 目标 ε represents the carbon content in the target steel grade, in ppm; ε is the error coefficient between the thermodynamic equilibrium state and the actual non-equilibrium state, ranging from 0.2 to 0.8, dimensionless; m 钢液 The mass of molten steel is expressed in tons (t); p represents the vacuum level in the RH vacuum chamber, expressed in Pa; m k P represents the mass of the carbonaceous deoxidizer in the k-th stage out of n pre-deoxidation stages, in kg; n is the total number of pre-deoxidation stages, dimensionless; 初始 P represents the vacuum level before the start of the k-th stage of injection, in Pa. 结束 φ represents the vacuum level at the end of the k-th stage, in Pa; φ represents the utilization rate of the carbonaceous deoxidizer, ranging from 80% to 100%, dimensionless; t k v represents the duration of the k-th stage out of n pre-deoxygenation stages, in minutes; k The injection rate is the k-th stage out of n pre-deoxygenation stages, expressed in kg / min.

[0006] Under high vacuum conditions, carbon (C) has a higher affinity for oxygen (O) than elements such as silicon (Si), providing the thermodynamic conditions for preferential deoxidation. Simultaneously, the CO bubbles generated by the carbon-oxygen reaction, as they rise in the molten steel, provide attachment points and removal channels for dissolved nitrogen (N), achieving a carbon-oxygen reaction-driven denitrification effect. Based on this, introducing an external carbonaceous deoxidizer for pre-deoxidation during the decarburization stage of RH refining can simultaneously reduce the oxygen and nitrogen content in the molten steel before deoxidation and improve the cleanliness of the steel.

[0007] In the existing technology, the crude method of simply adding deoxidizer in batches has obvious shortcomings: (1) the carbon-oxygen reaction is too concentrated and intense, resulting in violent turbulence on the surface of the molten steel; (2) the intense reaction and molten steel splashing cause a significant temperature drop; (3) the splashed molten steel is easy to solidify on the furnace wall of the vacuum chamber to form cold steel, affecting the normal operation of the equipment and the stability of the process; (4) carbonaceous deoxidizers cannot be added under high vacuum. In addition, the deoxidizer added before the start of vacuuming will react with oxygen in the air, causing losses and increasing production costs. The amount of deoxidizer added during vacuuming needs to be controlled to avoid the formation of cold steel. Adding deoxidizer after decarburization causes carbon increase in the molten steel, which is not conducive to the control of the composition of the molten steel. Therefore, this application achieves efficient pre-deoxidation by dividing the pre-deoxidation stage into n stages and accurately calculating the injection volume, injection rate and injection time of each stage, so as to significantly reduce the dissolved oxygen content in the molten steel and create favorable conditions for subsequent deep deoxidation.

[0008] Preferably, when the vacuum degree is greater than 10000 and less than or equal to 100000 Pa, the mass of the carbonaceous deoxidizer injected accounts for the mass of the m... 总 40-60%, blowing time 3-5 minutes; When the vacuum degree is greater than 1585 Pa and less than or equal to 10000 Pa, the mass of the carbonaceous deoxidizer injected accounts for the mass of the m 总 10-30%, blowing time 2-4 minutes; When the vacuum degree is greater than 398 Pa and less than or equal to 1585 Pa, the mass of the carbonaceous deoxidizer injected accounts for the mass of the m... 总 10-20%, blowing time 2-4 minutes; When the vacuum degree is greater than 158 and less than or equal to 398 Pa, the mass of the carbonaceous deoxidizer injected accounts for the mass of the m... 总 5-10%, blowing time 2-4 minutes; When the vacuum degree is greater than 100 and less than or equal to 158 Pa, the blowing time is 1-5 minutes.

[0009] Preferably, the carbonaceous deoxidizer includes one or more of graphite powder, coke powder, coal powder, and biochar powder.

[0010] Preferably, the particle size of the carbonaceous deoxidizer is 50-500 mesh.

[0011] Preferably, the carrier gas includes argon and / or carbon dioxide.

[0012] Preferably, the carbonaceous deoxidizer is fluidized with pressurized gas before being injected; The pressurized gas includes argon and / or carbon dioxide.

[0013] Preferably, the carbonaceous deoxidizer is sprayed inside the riser pipe of the RH vacuum chamber or 30-250 mm directly below the riser pipe.

[0014] Preferably, when the actual oxygen content O 实际 When the value is less than or equal to 280 ppm, it is determined that the conditions for entering the formal deoxygenation period are met.

[0015] This application also provides a system for RH vacuum air-solid injection pollution-free deoxidation smelting of high-performance steel, for performing the aforementioned RH vacuum air-solid injection pollution-free deoxidation smelting of high-performance steel, the system comprising: Gas storage tanks are used to store carrier gases and pressurized gases; Carbonaceous deoxidizer storage tank, used to store carbonaceous deoxidizer; A ladle is used to store molten steel. RH vacuum chamber, used for RH refining; The gas storage tank and the carbonaceous deoxidizer storage tank are connected by a pressurized gas pipeline. The pressurized gas pipeline is sequentially equipped with a gas main control valve group and a pressurized gas injection valve group along the gas flow direction. The outlet of the carbonaceous deoxidizer storage tank is connected to one end of the injection pipeline, and the other end of the injection pipeline is located inside the riser pipe of the RH vacuum chamber or directly below the riser pipe. The injection pipeline is connected to the pressurized gas pipeline between the gas main control valve group and the pressurized gas injection valve group through a flow-carrying gas pipeline. One end of the riser tube of the RH vacuum chamber is immersed in the molten steel in the ladle.

[0016] Preferably, the RH vacuum chamber, the gas main control valve group, and the pressurized gas injection valve group are controlled by a PLC control cabinet and an electronic computer.

[0017] Compared with the prior art, the beneficial effects of this application include: The method and system for RH vacuum air-solid injection pollution-free deoxidation smelting of high-performance steel provided in this application achieves efficient pre-deoxidation by dividing the pre-deoxidation stage into n stages and accurately calculating the injection volume, injection rate, and injection time of each stage. This significantly reduces the dissolved oxygen content in the molten steel by approximately 150 ppm, creating favorable conditions for subsequent deep deoxidation. Furthermore, the carbon-oxygen reaction generates a large number of fine CO bubbles in situ. These bubbles rise in the molten steel, providing an efficient bubble interface and kinetic conditions for denitrification ([N]). The injection of carbonaceous deoxidizer and its induction... The intense carbon-oxygen reaction generates a large amount of additional gas (CO), which significantly enhances the circulation and stirring intensity of the molten steel in the RH vacuum chamber, promoting compositional homogenization. Because the pre-deoxidation significantly reduces the initial oxygen content of the molten steel during the deoxidation period, the consumption of aluminum deoxidizers (such as aluminum balls) is directly reduced in the subsequent formal deoxidation stage. This not only reduces the content of Al2O3 inclusions generated by aluminum deoxidation, improving the cleanliness of the molten steel, but also alleviates the burden on subsequent calcium treatment processes (such as the amount of calcium required for modifying Al2O3 inclusions), effectively reducing production costs. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0019] Figure 1 The embodiment provides a system for the pollution-free deoxidation and smelting of high-performance steel using RH vacuum air-solid jetting. Figure 2 Here is an SEM image of the smelting product obtained in Example 4; Figure 3 The image shows the SEM image of the smelting product obtained in Comparative Example 2.

[0020] Figure label: 1-Gas storage tank; 2-Carbonous deoxidizer storage tank; 3-Steel ladle; 4-Molten steel; 5-RH vacuum chamber; 6-Pressurized gas pipeline; 7-Main gas control valve assembly; 8-Pressurized gas injection valve assembly; 9-Purge pipeline; 10-Rising pipe; 11-Carbonous deoxidizer fluidized bed ejection control valve assembly; 12-Gas pipeline valve assembly; 13-PLC control cabinet; 14-Electronic computer. Detailed Implementation

[0021] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0022] Example 1 like Figure 1 As shown, this embodiment provides a system for pollution-free deoxidation and smelting of high-performance steel using RH vacuum air-solid injection, including: a gas storage tank 1, a carbonaceous deoxidizer storage tank 2, a ladle 3 (containing molten steel 4), and an RH vacuum chamber 5; the gas storage tank 1 is used to store the carrier gas and the pressurizing gas, which are argon or carbon dioxide, and can be the same or different, and multiple storage tanks are used for storage when they are different; the carbonaceous deoxidizer storage tank 2 is used to store the carbonaceous deoxidizer, which can be one or more of graphite powder, coke powder, coal powder, and biomass charcoal powder.

[0023] Gas storage tank 1 and carbonaceous deoxidizer storage tank 2 are connected by a pressurized gas pipeline 6. The pressurized gas pipeline 6 is sequentially equipped with a gas main control valve group 7 and a pressurized gas injection valve group 8 along the gas flow direction. The outlet of carbonaceous deoxidizer storage tank 2 is connected to one end of a jetting pipeline 9, the other end of which is located inside or directly below the riser pipe 10 of the RH vacuum chamber 5. The jetting pipeline 9 is connected to the pressurized gas pipeline 6 between the gas main control valve group 7 and the pressurized gas injection valve group 8 via a flow-carrying gas pipeline. A carbonaceous deoxidizer fluidized bed ejection control valve group 11 is installed on the jetting pipeline 9 at the outlet of carbonaceous deoxidizer storage tank 2. A gas pipeline valve group 12 is installed between the carbonaceous deoxidizer fluidized bed ejection control valve group 11 and the outlet of the jetting pipeline 9. One end of the riser pipe 10 of the RH vacuum chamber 5 is immersed in the molten steel 4 in the ladle 3. The RH vacuum chamber 5, the gas main control valve group 7, and the pressurized gas injection valve group 8 are controlled by the PLC control cabinet 13 and the electronic computer 14.

[0024] Example 2 This embodiment provides a pollution-free deoxidation method for high-performance steel smelting using vacuum air-solid injection in an RH furnace, for producing IF steel in a 210tRH furnace. The method utilizes the system provided in Example 1 and includes the following steps: When the ladle arrives at the RH station, the oxygen content (O3) is determined by oxygen and carbon determination. 到站 The carbon content is 610 ppm. 到站 The target carbon content at the smelting endpoint is 245 ppm. 目标 The concentration was 30 ppm, and the oxygen content was O. 目标 Compress to 20 ppm.

[0025] Calculate the total carbon injection amount (m) according to Formula 1. 总 : ; m 总=(610-20-245+30)×0.5×210×12 / 16×0.001=29.53kg. Highly reactive graphite powder (particle size 50 mesh, fixed carbon ≥99%) was selected as the deoxidizer and sprayed in through a horizontal spray gun in an ascending pipe.

[0026] The injection rate is controlled by a third-order decrease as the vacuum level increases (calculated using the following formula): ; ; ; Initial stage (100000-3162Pa): v k =0.9×14.76 / 5=2.657kg / min, inject 50% of the total amount (14.76kg) at a high speed of 2.657kg / min, the carrier gas is an Ar / CO2 mixture (volume ratio 8:2), and the carbon-oxygen reaction is started slowly in a low vacuum environment; Transition stage (vacuum degree 3162-316.2 Pa): v k =0.9×9.83 / 5=1.769kg / min, the rate drops to 1.769kg / min, which is 33.33% (9.83kg) of the total injected volume, and the carrier gas ratio is the same as above; Terminal stage (316.2-99.9 Pa): v k =0.9×4.94 / 3=1.482kg / min, the rate is further reduced to 1.482kg / min to complete the remaining 16.67% (4.94kg) of blowing, the carrier gas ratio is the same as above, the vacuum chamber pressure is maintained at 67Pa for 150 seconds, and the total blowing time is 13min.

[0027] After adopting the above method, the oxygen content stabilized at 248 ppm, the nitrogen content decreased from 48 ppm to 39 ppm, the aluminum ball consumption was reduced by 36.9 kg during the deoxidation period, and the number of inclusions (5-10 μm) was 85.4 per 100 mm. 2 The number of 10-15μm particles is 6.7 per 100mm. 2 .

[0028] Example 3 This embodiment provides a pollution-free deoxidation smelting method for high-performance steel using RH vacuum air-solid injection, applied to a 190tRH furnace for producing non-oriented silicon steel. The method utilizes the system provided in Example 1 and includes the following steps: When the ladle arrives at the RH station, the oxygen content (O3) is determined by oxygen and carbon determination. 到站 The carbon content is 595 ppm. 到站The value is 223 ppm. The target carbon content (C) at the smelting endpoint is... 目标 The concentration was 20 ppm, and the oxygen content was O. 目标 Compress to 20 ppm.

[0029] Calculate the total carbon injection amount (m) according to Formula 1. 总 : ; m 总 =(595-20-223+20)×0.4×190×12 / 16×0.001=21.20kg. Straw biochar (70 mesh particle size, fixed carbon ≥90%) was selected as the deoxidizer and sprayed in through a horizontal spray gun in the riser pipe.

[0030] The injection rate is controlled by a fourth-order decrease as the vacuum level increases (calculated using the following formula): ; ; ; Phase 1 (100000-6309Pa): v k =0.9×8.48 / 3=2.544kg / min, 40% of the total high-speed injection (8.48kg), the carrier gas is an Ar / CO2 mixture (volume ratio 7:3). Second stage (vacuum degree 6309-794 Pa): v k =0.9×6.36 / 3=1.908kg / min, 30% of the total injected volume (6.36kg), the carrier gas ratio is the same as above; Third stage (vacuum degree 794-199 Pa): v k =0.9×4.24 / 2=1.908kg / min, completing the remaining 20% ​​(4.24kg) of injection, with the carrier gas ratio as above; Phase 4 (199-99.7 Pa): v k =0.9×2.12 / 2=0.954kg / min, complete the remaining 10% (2.12kg) of blowing, the carrier gas ratio is the same as above; Maintain the vacuum chamber pressure at 75 Pa for 130 seconds, with a total blowing time of 10 minutes.

[0031] After adopting the above method, the oxygen content stabilized at 246 ppm, the nitrogen content decreased from 51 ppm to 39 ppm, the aluminum ball consumption was reduced by 27.3 kg during the deoxidation period, and the number of inclusions (5-10 μm) was 95.3 per 100 mm. 2The number of 10-15μm particles is 5.4 per 100mm. 2 The number of particles larger than 15μm is 1.2 per 100mm. 2 .

[0032] Example 4 This embodiment provides a method for pollution-free deoxidation smelting of high-performance steel using RH vacuum air-solid injection, applied to the production of automotive outer panels in a 190tRH furnace. The method utilizes the system provided in Embodiment 1 and includes the following steps: When the ladle arrives at the RH station, the oxygen content (O3) is determined by oxygen and carbon determination. 到站 The carbon content is 622 ppm. 到站 The value is 214 ppm. The target carbon content (C) at the smelting endpoint is... 目标 The oxygen content is ≤90ppm. 目标 Compress to 20 ppm.

[0033] Calculate the total carbon injection amount (m) according to Formula 1. 总 : ; m 总 =(622-20-214+90)×0.4×190×12 / 16×0.001=27.25kg. High-purity graphite (65 mesh particle size, fixed carbon ≥99%) was selected as the deoxidizer and sprayed in through a horizontal spray gun in the riser pipe.

[0034] The injection rate is controlled in a five-order decreasing manner as the vacuum level increases (calculated using the following formula): ; ; ; Phase 1 (100000-10000Pa): v k =0.9×9.07 / 3=2.721kg / min, 33.3% (9.07kg) of the total high-speed injection, the carrier gas is an Ar / CO2 mixture (volume ratio 7:3). Second stage (vacuum degree 10000-1585Pa): v k =0.9×7.28 / 3=2.184kg / min, which is 26.7% (7.28kg) of the total injected volume, and the carrier gas ratio is the same as above; Third stage (vacuum degree 1585-398Pa): v k =0.9×5.45 / 3=1.635kg / min, 20% of the total injection volume (5.45kg), the carrier gas ratio is the same as above; Fourth stage (vacuum degree 398-158 Pa): v k =0.9×3.62 / 3=1.086kg / min, which is 13.3% (3.62kg) of the total injected volume, and the carrier gas ratio is the same as above; Fifth stage (158-99.7 Pa): v k =0.9×1.83 / 2=0.824kg / min, complete the remaining 1.83kg injection, the carrier gas ratio is the same as above, maintain the vacuum chamber pressure at 67Pa for 130 seconds, and the total injection time is 14min.

[0035] After adopting the above method, the oxygen content stabilized at 246 ppm, the nitrogen content decreased from 51 ppm to 39 ppm, the aluminum ball consumption was reduced by 35 kg during the deoxidation period, and the number of inclusions (5-10 μm) was 95.3 per 100 mm. 2 The number of 10-15μm particles is 5.4 per 100mm. 2 The number of particles larger than 15μm is 1.2 per 100mm. 2 .

[0036] The shape and size of the inclusions are as follows Figure 2 As shown.

[0037] Example 5 This embodiment provides a method for pollution-free deoxidation smelting of high-performance steel using RH vacuum air-solid injection, applied to the production of automotive outer panels in a 190tRH furnace. The method utilizes the system provided in Embodiment 1 and includes the following steps: When the ladle arrives at the RH station, the oxygen content (O3) is determined by oxygen and carbon determination. 到站 The carbon content is 618 ppm. 到站 The target carbon content at the smelting endpoint is 210 ppm. 目标 The oxygen content is ≤90ppm. 目标 Compress to 20 ppm.

[0038] Calculate the total carbon injection amount (m) according to Formula 1. 总 : ; m 总 =(618-20-210+90)×0.4×190×12 / 16×0.001=27.25kg. High-purity graphite (65 mesh particle size, fixed carbon ≥99%) was selected as the deoxidizer and sprayed in through a horizontal spray gun in the riser pipe.

[0039] The injection rate is controlled by a third-order decrease as the vacuum level increases (calculated using the following formula): ; ; ; Phase 1 (100000-3162Pa): v k =0.9×13.63 / 6=2.045kg / min, 50% of the total high-speed injection (13.63kg), the carrier gas is an Ar / CO2 mixture (volume ratio 7:3). Second stage (vacuum degree 3162-316.2 Pa): v k =0.9×9.08 / 5=1.634kg / min, which is 33.33% of the total injected volume (9.08kg), and the carrier gas ratio is the same as above; Third stage (vacuum degree 316.2-99.9 Pa): v k =0.9×4.54 / 4=1.022kg / min, 16.67% (4.54kg) of the total amount injected, the carrier gas ratio is the same as above; maintain the vacuum chamber pressure at 67Pa for 130 seconds, and the total injection time is 15min.

[0040] After adopting the above method, the oxygen content stabilized at 255 ppm, the nitrogen content decreased from 54 ppm to 46 ppm, the aluminum ball consumption was reduced by 32.7 kg during the deoxidation period, and the number of inclusions (5-10 μm) was 102 per 100 mm. 2 The number of 10-15μm particles is 6.3 per 100mm. 2 The number of particles larger than 15μm is 1.5 per 100mm. 2 The carbon content of the molten steel after leaving the station (RH) is 80 ppm, and the oxygen content is 18 ppm.

[0041] A comparison of Examples 4 and 5 shows that, under roughly the same conditions, performing carbonaceous deoxidizer injection in five stages yields better results.

[0042] Comparative Example 1 Compared with Example 4, this scheme involves the production of IF steel in a 190tRH furnace. When the ladle arrives at the RH station, slag breaking and sampling show an oxygen content of 602ppm and a carbon content of 251ppm. Carbon powder is then added in batches of 9, 10, 9, and 10kg directly through the RH alloy feed pipe. The molten steel in the RH vacuum chamber experiences violent fluctuations, and the number of inclusions (5-10μm) is 124 per 100mm. 2 The number of 10-15μm particles is 13.5 per 100mm. 2 The number of particles larger than 15μm is 1.7 per 100mm. 2After smelting, approximately 3 cm of cold steel was observed on the furnace wall. Directly adding a large amount of carbon powder resulted in a violent carbon-oxygen reaction, causing significant fluctuations on the surface of the molten steel and a rapid drop in temperature. Some of the molten steel adhered to the furnace wall, forming cold steel. Furthermore, due to the vacuum chamber's suction effect, carbon powder was easily drawn out, leading to substantial waste. The drawbacks of this method are the negative impact of the cold steel on furnace conditions and excessive carbon powder loss.

[0043] Comparative Example 2 In a 260tRH furnace producing IF steel, when the ladle arrives at the RH station, slag sampling and oxygen / carbon determination show an oxygen content of 613 ppm and a carbon content of 247 ppm. After routine RH treatment, the oxygen content at the end of decarburization is 348 ppm, 280 kg of aluminum particles are consumed, the nitrogen content is 55 ppm, and the number of inclusions (5-10 μm) is 152.9 per 100 mm. 2 The number of 10-15μm particles is 21.5 per 100mm. 2 The number of particles larger than 15μm is 1.9 per 100mm. 2 .

[0044] The shape and size of the inclusions are as follows Figure 3 As shown.

[0045] This scheme is the traditional smelting method used in steel mills. Because the oxygen content at the end of decarburization is significantly higher than in the new scheme, a large amount of aluminum needs to be added for deoxidation. The inclusions formed by the combination of aluminum and oxygen are alumina (Type B) inclusions, resulting in more inclusions.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for pollution-free deoxidation smelting of high-performance steel using RH vacuum air-solid injection, characterized in that, include: Determine the initial oxygen content (O) of the molten steel at the RH station. 到站 Initial carbon content C 到站 and the mass of molten steel m 钢液 Divide the process into n pre-deoxidation stages, and calculate the total mass m of the required carbonaceous deoxidizer using Formula 1. 总 Then, using Formula 2, the mass m of the carbonaceous deoxidizer in the kth stage of the n pre-deoxidation stages is calculated. k The final vacuum degree P of the kth stage is calculated using Formula 3. 结束 Then, the carbonaceous deoxidizer injection rate v for each stage is calculated using Formula 4. k ; RH is started, and the carrier gas is injected into the molten steel to pre-deoxidize the fluidized carbonaceous deoxidizer, while controlling the flow rate of the carrier gas and the vacuum degree P. 结束 To satisfy the m 总 The m k and the v k ; After the blowing process is completed and the composition of the molten steel stabilizes, measure the actual oxygen content (O) of the molten steel. 实际 According to the actual oxygen content O 实际 Determine whether the conditions for entering the formal deoxidation period are met; if not, repeat the injection of the fluidized carbonaceous deoxidizer until the conditions for entering the formal deoxidation period are met. Formula 1 is: ； Formula 2 is: ； Formula 3 is: ； Formula 4 is: ； Where, m 总 The total mass of the required carbonaceous deoxidizer is expressed in kg; O 到站 The initial oxygen content of molten steel, in ppm; C 到站 The initial carbon content of the molten steel, in ppm; O 目标 Oxygen content in the target steel grade, in ppm; C 目标 ε represents the carbon content in the target steel grade, in ppm; ε is the error coefficient between the thermodynamic equilibrium state and the actual non-equilibrium state, ranging from 0.2 to 0.8, dimensionless; m 钢液 The mass of molten steel is expressed in tons (t); p represents the vacuum level in the RH vacuum chamber, expressed in Pa; m k P represents the mass of the carbonaceous deoxidizer in the k-th stage out of n pre-deoxidation stages, in kg; n is the total number of pre-deoxidation stages, dimensionless; 初始 P represents the vacuum level before the start of the k-th stage of injection, in Pa. 结束 φ represents the vacuum level at the end of the k-th stage, in Pa; φ represents the utilization rate of the carbonaceous deoxidizer, ranging from 80% to 100%, dimensionless; t k v represents the duration of the k-th stage out of n pre-deoxygenation stages, in minutes; k The injection rate is the k-th stage out of n pre-deoxygenation stages, expressed in kg / min.

2. The method for RH vacuum air-solid injection pollution-free deoxidation smelting of high-performance steel according to claim 1, characterized in that, n=5； When the vacuum degree is greater than 10000 Pa and less than or equal to 100000 Pa, the mass of the carbonaceous deoxidizer injected accounts for the mass of m. 总 40-60%, blowing time 3-5 minutes; When the vacuum degree is greater than 1585 Pa and less than or equal to 10000 Pa, the mass of the carbonaceous deoxidizer injected accounts for the mass of the m 总 10-30%, blowing time 2-4 minutes; When the vacuum degree is greater than 398 Pa and less than or equal to 1585 Pa, the mass of the carbonaceous deoxidizer injected accounts for the mass of the m... 总 10-20%, blowing time 2-4 minutes; When the vacuum degree is greater than 398 Pa and less than or equal to 158 Pa, the mass of the carbonaceous deoxidizer injected accounts for the mass of the m... 总 5-10%, blowing time 2-4 minutes; When the vacuum degree is greater than 100 Pa and less than or equal to 158 Pa, the remaining carbonaceous deoxidizer is sprayed for 1-5 minutes.

3. The method for RH vacuum air-solid injection pollution-free deoxidation smelting of high-performance steel according to claim 1, characterized in that, The carbonaceous deoxidizer includes one or more of graphite powder, coke powder, coal powder, and biochar powder.

4. The method for RH vacuum air-solid jetting pollution-free deoxidation smelting of high-performance steel according to claim 3, characterized in that, The particle size of the carbonaceous deoxidizer is 50-500 mesh.

5. The method for RH vacuum air-solid injection pollution-free deoxidation smelting of high-performance steel according to claim 1, characterized in that, The carrier gas includes argon and / or carbon dioxide.

6. The method for RH vacuum air-solid injection pollution-free deoxidation smelting of high-performance steel according to claim 1, characterized in that, The carbonaceous deoxidizer is fluidized with pressurized gas before being injected. The pressurized gas includes argon and / or carbon dioxide.

7. The method for RH vacuum air-solid injection pollution-free deoxidation smelting of high-performance steel according to claim 1, characterized in that, The carbonaceous deoxidizer is sprayed inside the riser pipe of the RH vacuum chamber or 30-250mm directly below the riser pipe.

8. The method for RH vacuum air-solid injection pollution-free deoxidation smelting of high-performance steel according to any one of claims 1-7, characterized in that, When the actual oxygen content O 实际 When the value is less than or equal to 280 ppm, it is determined that the conditions for entering the formal deoxygenation period are met.

9. A system for pollution-free deoxidation and smelting of high-performance steel using RH vacuum air-solid injection, characterized in that, A system for performing the RH vacuum air-solid injection pollution-free deoxidation smelting method for high-performance steel according to any one of claims 1-8, the system comprising: Gas storage tanks are used to store carrier gases and pressurized gases; Carbonaceous deoxidizer storage tank, used to store carbonaceous deoxidizer; A ladle is used to store molten steel. RH vacuum chamber, used for RH refining; The gas storage tank and the carbonaceous deoxidizer storage tank are connected by a pressurized gas pipeline. The pressurized gas pipeline is sequentially equipped with a gas main control valve group and a pressurized gas injection valve group along the gas flow direction. The outlet of the carbonaceous deoxidizer storage tank is connected to one end of the injection pipeline, and the other end of the injection pipeline is located inside the riser pipe of the RH vacuum chamber or directly below the riser pipe. The injection pipeline is connected to the pressurized gas pipeline between the gas main control valve group and the pressurized gas injection valve group through a flow-carrying gas pipeline. One end of the riser tube of the RH vacuum chamber is immersed in the molten steel in the ladle.

10. The system for RH vacuum air-solid injection pollution-free deoxidation smelting of high-performance steel according to claim 9, characterized in that, The RH vacuum chamber, the gas main control valve group, and the pressurized gas injection valve group are controlled by a PLC control cabinet and an electronic computer.

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