High-carbon steel wire rod smelting process and smelting system of short-process electric furnace

Abstract

The invention relates to a high-carbon steel wire rod smelting process and smelting system of a short-process electric furnace, the smelting stage in the furnace is divided into several stages of a scrap steel adding stage, an iron mixing stage, a molten pool forming stage, a melting temperature rising stage and a component adjusting stage, and the oxygen supply time and the oxygen supply flow are adjusted according to the oxygen supply demand characteristics of different smelting stages. The oxygen supply in the furnace is accurately controlled, the stirring effect of a molten pool is improved, the melting of scrap iron is accelerated, and the dephosphorization effect is improved, so that the smelting efficiency is improved, and the end point control is stable.

Description

Technical Field

[0001] The invention relates to a high-carbon steel wire smelting process and a smelting system for a short-process electric furnace, belonging to the technical field of iron and steel metallurgy. Background Art

[0002] With the development of industry, electric furnace steelmaking has developed rapidly. This is because the electric furnace short-process smelting process uses scrap steel as the main raw material. Compared with the blast furnace-converter long-process smelting process, the short-process process reduces energy consumption by 50% and CO2 emissions by 75%.

[0003] In the electric furnace short process, in order to improve the stirring effect of the molten pool during the electric furnace smelting process, improve the uniformity of the molten pool, accelerate the melting of scrap steel, and accelerate the removal of impurity elements, a certain amount of oxygen needs to be blown in during the electric furnace smelting process. The blowing of oxygen is of great significance for improving the stirring effect of the molten pool, accelerating the melting of scrap steel, increasing the removal rate of impurity elements such as phosphorus, and improving the stability of endpoint control.

[0004] Regarding the oxygen supply system during the smelting process, the timing and amount of blowing are key factors. At present, the most common way to control the oxygen supply system mainly relies on long-term smelting experience. When the power consumption of electric furnace smelting reaches a certain stage or the melting state of scrap steel is estimated, the oxygen supply flow rate and the timing of oxygen supply are adjusted. For example, the application with publication number CN102312044A provides an electric furnace smelting method, in which when the scrap steel near the oxygen gun melts or the adjacent scrap steel material is red hot, the furnace wall gun starts to supply oxygen; when the power consumption reaches a certain amount, the oxygen supply is stopped or the oxygen supply intensity is changed. However, since electric furnace smelting is in a black box state, it is difficult to achieve precise control of oxygen supply in the electric furnace smelting process based on experience alone. The application with publication number CN113215354A provides an electric furnace full scrap steel smelting process. This method adjusts and controls the timing and flow of oxygen supply from the furnace wall gun based on the power consumption of the electric furnace smelting process. In fact, due to changes in factors such as the type of scrap steel entering the furnace, the combination method, and the timing of adding molten iron, it is impossible to accurately control the oxygen supply only by the power consumption, which has a great impact on the smelting efficiency, smelting cost and end point control stability. Summary of the invention

[0005] The present invention provides a high-carbon steel wire smelting process and a smelting system for a short-process electric furnace, which can realize precise control of oxygen supply in the furnace, improve the stirring effect of the molten pool, accelerate the melting of scrap steel, and improve the dephosphorization effect, thereby realizing the improvement of smelting efficiency and the stability of endpoint control.

[0006] The technical solution adopted by the present invention to solve its technical problem is: A high carbon steel wire smelting process in a short-process electric furnace comprises the following steps: Step S1, KR molten iron pretreatment; Step S2, electric furnace smelting, select the factors affecting the oxygen supply of the electric furnace from the database, and use the least squares method to fit the required oxygen supply for the furnace to be smelted, where the influencing factors include the weight of the molten iron entering the furnace and the silicon content of the molten iron entering the furnace. The calculation formula for confirming the required oxygen supply for the furnace to be smelted is: , is the weight of molten iron entering the furnace, is the silicon content of molten iron entering the furnace, The oxygen supply required for the smelting furnace, in Nm 3 ; Obtain the molten iron addition conditions on the iron addition side, the electrode height change, and the oxygen supply and oxygen consumption conditions in the electric furnace, and divide the electric furnace smelting process into the scrap steel addition period, the iron addition period, the molten pool formation period, the melting temperature rise period, and the composition adjustment period; during the scrap steel addition period, the iron addition period, the molten pool formation period, the melting temperature rise period, and the composition adjustment period, adjust the oxygen supply timing and oxygen supply flow rate according to the oxygen supply curve; The end point composition and temperature control requirements of the steel to be smelted are determined from the database at the same time, and steel tapping begins when the determined control requirements are met; Step S3, LF refining, after the steel is tapped, the ladle is hoisted into the LF refining station to complete the temperature and composition adjustment, and the temperature of the molten steel is controlled within the set range; Step S4, casting of large square billets by continuous casting machine, protection casting during the whole continuous casting process, using low basicity and low alumina tundish covering agent, using low melting point crystallizer protection slag, and using crystallizer electromagnetic stirring; the second cooling section adopts weak cooling mode, and different water volumes are set in the four zones of the second cooling section; Step S5, blanking; Step S6, high-speed wire rolling; Furthermore, the endpoint composition of the steel to be smelted determined from the database includes, by mass fraction: C>0.04%, P<0.012%, S<0.012%; N<50ppm; endpoint temperature>1600°C; Furthermore, the chemical composition of the scrap steel added during the scrap steel adding period includes, by mass percentage: S≤0.005%, Ni≤0.01%, Cr≤0.03%, Cu≤0.01%, Al≤0.01%, Ti≤0.01%; Furthermore, the charging amount of the electric furnace is controlled at 115t-118t, and the ratio of molten iron into the furnace is controlled at 25%-50%; Furthermore, the lime consumption range of the electric furnace smelting process is 30-35kg / t, and the secondary side voltage control range during the power-on process is 713V-900V; Further, in step S2, the scrap steel adding period is defined as the time period from the addition of scrap steel to the start of power on, the iron adding period is defined as the time period from the start of power on to the completion of molten iron adding, the molten pool formation period is defined as the time period from the completion of molten iron adding to the drop of the electrode height to the lowest point, the melting temperature rise period is defined as the time period from the drop of the electrode height to the lowest point to the oxygen supply reaching 90% of the oxygen supply required for the smelting furnace, and the composition adjustment period is defined as the time period from the oxygen supply reaching 90% of the oxygen supply required for the smelting furnace to the end of smelting of the steel grade to be smelted; During the scrap steel adding period, set the main oxygen flow rate to 100-120Nm 3 / h, epoxy flow rate is 100-120 Nm 3 / h, coke oven gas flow rate is 80-100Nm 3 / h; During the iron addition period, set the main oxygen flow rate to 200-250Nm 3 / h, epoxy flow rate is 200-250 Nm 3 / h, coke oven gas flow rate is 400-500Nm 3 / h; During the molten pool formation period, set the main oxygen flow rate to 1000-1200Nm 3 / h, epoxy flow rate is 100-120 Nm 3 / h, coke oven gas flow rate is 100-120Nm 3 / h; During the melting and heating period, set the main oxygen flow rate to 1600-1800Nm 3 / h, epoxy flow rate is 100-120 Nm 3 / h, coke oven gas flow rate is 100-120Nm 3 / h; During the composition adjustment period, the main oxygen flow rate is 1400-1500Nm 3 / h, epoxy flow rate is 100-120 Nm 3 / h, coke oven gas flow rate is 100-120Nm 3 / h; Furthermore, when one-third of the steel is discharged from the electric furnace, a low-nitrogen carburizer is added, and metallic manganese and low-titanium and low-aluminum ferrosilicon are added for pre-deoxidation; during LF refining, the temperature of the molten steel is controlled at 1525℃-1535℃; After the temperature and composition of LF refining are adjusted, the argon gas at the bottom of the ladle is adjusted to a soft stirring state to remove inclusions. The argon gas flow rate is set to 60 NL / min -110NL / min, and the soft stirring time is set to 26min -31min; Furthermore, when casting with a large square billet continuous casting machine, the superheat of the molten steel in the tundish is controlled to be 20°C-30°C; the water volume of the crystallizer is set to 2975 L / min-3025 L / min; The water volume of the four zones in the secondary cooling section is set to 60 NL / min -100 NL / min, 20 NL / min -50 NL / min, 20 NL / min -40 NL / min, and 10 NL / min-30 NL / min in sequence; Furthermore, in the blanking process, the blanking heating temperature is set to 1180°C-1250°C, and the blank is formed into 140mm×140mm; In the high-speed wire rolling process, the heating temperature is set to 1080℃-1160℃, the rolling temperature is set to 960℃-1030℃, and the wire laying temperature is set to 860℃-920℃; A smelting system for the high-carbon steel wire smelting process of the short-process electric furnace, comprising electrodes, industrial cameras, a draw-wire encoder, and several supersonic cluster oxygen lances; The electrode is inserted into the electric furnace and connected to the electrode lifting hydraulic cylinder through the electrode cross arm. The pull rope of the pull rope encoder is installed on the electrode lifting hydraulic cylinder. When the electrode moves up and down in the electric furnace, the pull rope encoder can measure the height change of the electrode in real time; Industrial cameras are installed on the iron-adding side of the ladle to monitor the iron-adding conditions in real time; A supersonic beam oxygen lance is installed on both sides of the furnace door of the electric furnace. The position deviated from the center relative to the center of the electric furnace is defined as an eccentric area, and a supersonic beam oxygen lance is installed in each eccentric area.

[0007] Through the above technical solution, compared with the prior art, the present invention has the following beneficial effects: 1. The high carbon steel wire smelting process of the short-process electric furnace provided by the present invention divides the smelting stage in the furnace into several stages: scrap steel adding stage, iron adding stage, molten pool forming stage, melting temperature rising stage and composition adjustment stage. According to the oxygen supply demand characteristics of different smelting stages, the oxygen supply timing and oxygen supply flow rate are adjusted to improve the smelting effect of the electric furnace; 2. The smelting system of the high-carbon steel wire smelting process provided by the present invention can provide real-time feedback on the addition of molten iron during the electric furnace smelting process and track the changes in electrode height in real time, perform dynamic analysis of the smelting state, and achieve precise control of oxygen supply during the electric furnace smelting process. DETAILED DESCRIPTION

[0008] The present invention is now described in further detail. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the protection scope of the present invention.

[0009] As explained in the background technology, in actual working conditions, electric furnace smelting is in a black box state, and there is a lack of proper feedback on changes in factors such as the type of scrap steel entering the furnace, the matching method, and the timing of adding molten iron, making it impossible to dynamically analyze the smelting state during the electric furnace smelting process.

[0010] The present application provides a short-process electric furnace high-carbon steel wire smelting process, which uses corresponding monitoring means to provide real-time feedback on the smelting status in the furnace, dynamically analyzes the smelting status, and refines the entire smelting stage into: scrap steel addition period, iron addition period, molten pool formation period, melting temperature rise period, and composition adjustment period. Then, according to the oxygen supply demand characteristics of different smelting stages, the oxygen supply timing and oxygen supply flow rate are adjusted to improve the electric furnace smelting effect.

[0011] The smelting process comprises the following steps: Step S1, KR molten iron pretreatment.

[0012] Step S2, electric furnace smelting, this step contains multiple innovations, first of all, it is about obtaining the oxygen supply required for the furnace to be smelted. Two innovations are included when obtaining, one is the selection of factors affecting the oxygen supply of the electric furnace, and the other is how to form the functional balance relationship between various factors. In the electric furnace smelting process, since molten iron needs oxygen to complete the oxidation reaction, if the weight of the molten iron increases, in order to make these oxidation reactions fully proceed, it is necessary to increase the oxygen supply accordingly, and at the same time, because the blowing of oxygen can play the role of stirring the molten pool, when the weight of the molten iron is large to form a deeper molten pool, enough oxygen is needed to penetrate the molten pool to promote the circulation of chemical reactions and the molten pool. Therefore, the weight of the molten iron entering the furnace must be one of the important factors affecting the oxygen supply.

[0013] Secondly, the oxidation reaction of silicon is one of the important reactions in the electric furnace smelting process. The higher the silicon content, the more oxygen is needed. In order to fully oxidize and remove silicon in this process, sufficient oxygen supply is required. The silicon dioxide produced by the oxidation reaction of silicon enters the slag, so the silicon content will change the viscosity and other properties of the slag. Therefore, the silicon content of the molten iron entering the furnace is the second important factor affecting the oxygen supply.

[0014] After selecting the influencing factors, assuming that there is a series of sample data in the database, including different molten iron weights, silicon contents and corresponding actual oxygen supplies, a linear model is needed to find the best function match for the data. At this time, the least squares method that minimizes the sum of squares of errors to find the best match is the most appropriate. Therefore, the influencing factors that affect the oxygen supply of the electric furnace are selected from the database, and the least squares method is used to fit the required oxygen supply for the smelting furnace to be smelted. Among them, the influencing factors include the weight of the molten iron entering the furnace and the silicon content of the molten iron entering the furnace. The calculation formula for confirming the required oxygen supply for the smelting furnace to be smelted is: , is the weight of molten iron entering the furnace, is the silicon content of molten iron entering the furnace, The oxygen supply required for the smelting furnace, in Nm 3 ;

[0015] Before smelting in an electric furnace, the charging amount of the electric furnace needs to be set at 115t-118t, and the ratio of molten iron to the furnace needs to be controlled at 25%-50%; after the start of smelting in an electric furnace, the smelting process of the electric furnace is divided into the scrap steel adding period, the iron adding period, the molten pool forming period, the melting temperature rising period and the composition adjustment period by detecting the molten iron adding condition on the iron adding side, the electrode height change and the oxygen supply and oxygen consumption condition in the electric furnace. At the same time, the oxygen supply timing and oxygen supply flow rate are adjusted according to the oxygen supply curves at different stages to improve the smelting effect of the electric furnace.

[0016] Specifically, the scrap steel adding period is defined as the time period from the addition of scrap steel to the start of power on. At this stage, the furnace is mainly filled with solid scrap steel, and almost no large-scale oxidation reaction occurs. At this time, the oxygen consumption is mainly used for a small amount of preheating oxidation in the furnace and removing impurities on the surface of the scrap steel. Since there is no molten pool, a large amount of oxygen is not required to participate in the reaction, so it is the initial stage of oxygen consumption. Therefore, the main oxygen flow rate is set to 100-120Nm 3 / h, epoxy flow rate is 100-120 Nm 3 / h, coke oven gas flow rate is 80-100Nm 3 / h. During this period, we start to pay attention to the oxygen supply to establish a suitable initial atmosphere in the furnace and create conditions for subsequent reactions.

[0017] Preferably, the present application also provides the scrap steel components added during the scrap steel adding period, and the chemical composition thereof includes, by mass percentage: S≤0.005%, Ni≤0.01%, Cr≤0.03%, Cu≤0.01%, Al≤0.01%, and Ti≤0.01%.

[0018] The iron addition period is defined as the time period from the start of power-on to the completion of iron addition. When iron is added, the elements in the iron (such as carbon, silicon, manganese, etc.) will react with oxygen for oxidation. The high temperature and high activity of the iron require a certain amount of oxygen to control the reaction process. For example, the decarburization reaction begins to proceed. Therefore, it needs to be divided separately to better control the oxygen supply and reaction. Specifically, the main oxygen flow rate is set to 200-250Nm 3 / h, epoxy flow rate is 200-250 Nm 3 / h, coke oven gas flow rate is 400-500Nm 3 / h.

[0019] The molten pool formation period is defined as the time period from the completion of molten iron addition to the drop of the electrode height to the lowest point. The main oxygen flow rate is set to 1000-1200Nm 3 / h, epoxy flow rate is 100-120 Nm 3 / h, coke oven gas flow rate is 100-120Nm 3 / h. The molten pool formation period is set separately because as the scrap steel continues to melt, the molten pool begins to form, the contact area between the molten steel and oxygen in the molten pool increases, the oxidation reaction becomes more intense, and the oxygen consumption increases significantly. This period is the transition stage from solid reaction to liquid reaction in the electric furnace smelting process. The supply of oxygen is crucial to the formation and stability of the molten pool and the continuation of the oxidation reaction. Therefore, it is divided according to the changing characteristics of oxygen consumption to facilitate accurate oxygen supply.

[0020] After the molten pool is formed, a large amount of heat is required to melt all the remaining solid scrap steel. In this process, oxygen consumption reaches a peak. In order to ensure the melting and heating efficiency, this period has significant differences in oxygen consumption and process requirements. Therefore, a melting and heating period is set, and it is defined as the time period from when the electrode height drops to the lowest point to when the oxygen supply reaches 90% of the oxygen supply required for the smelting furnace. Specifically, the main oxygen flow rate is set to 1600-1800Nm 3 / h, epoxy flow rate is 100-120 Nm 3 / h, coke oven gas flow rate is 100-120Nm 3 / h.

[0021] Finally, when all the molten steel is melted and the temperature reaches the required level, the composition adjustment begins. This is the composition adjustment period, which is defined as the time period from when the oxygen supply reaches 90% of the oxygen supply required for the smelting furnace to the end of smelting of the steel grade to be smelted. The focus of this period is to accurately control the composition of the molten steel. The oxygen supply is mainly used to fine-tune the reaction, which is different from the purpose of obtaining heat by supplying a large amount of oxygen during the melting and heating period. Therefore, it needs to be divided separately to control the oxygen flow rate according to the specific needs of the composition adjustment. Specifically, the main oxygen flow rate is set to 1400-1500Nm 3 / h, epoxy flow rate is 100-120 Nm 3 / h, coke oven gas flow rate is 100-120Nm 3 / h.

[0022] The endpoint composition of the steel to be smelted determined from the database includes, by mass fraction: C>0.04%, P<0.012%, S<0.012%; N<50ppm; endpoint temperature>1600℃. When the above settings are reached, steel tapping begins. When one-third of the steel is tapped from the electric furnace, a low-nitrogen carburizer is added, and metallic manganese and low-titanium, low-aluminum ferrosilicon are added for pre-deoxidation. After tapping is completed, the ladle is hoisted into the LF refining station for LF refining in step S3, and the temperature and composition adjustment are completed, and the temperature of the molten steel is controlled at 1525℃-1535℃.

[0023] After the composition adjustment is completed, gradually reduce the argon blowing at the bottom of the ladle to a soft stirring state to remove inclusions. Set the argon flow rate to 60 NL / min -110NL / min. In the early stage, observe the fluctuation of the slag surface frequently. When the slag surface fluctuates slightly, the soft stirring time is set to 26min -31min.

[0024] In the above-mentioned entire electric furnace smelting process, the lime consumption range is 30-35kg / t, and the secondary side voltage control range during the power-on process is 713V-900V.

[0025] Step S4, casting of large square billet continuous casting machine, protecting casting throughout the continuous casting process, using low-basicity and low-alumina tundish covering agent, controlling the superheat of molten steel in the tundish to 20℃-30℃; using low-melting point crystallizer protective slag, and using crystallizer electromagnetic stirring; setting the crystallizer water volume to 2975 L / min-3025L / min; the second cooling section adopts weak cooling mode, and the water volume of the four zones of the second cooling section is set to 60 NL / min-100 NL / min, 20 NL / min-50 NL / min, 20 NL / min-40 NL / min, and 10 NL / min-30 NL / min in sequence.

[0026] Step S5, blanking, setting the blanking heating temperature to 1180°C-1250°C, and blanking to 140mm×140mm.

[0027] Step S6, high-speed wire rolling, setting the heating temperature to 1080°C-1160°C, the rolling start temperature to 960°C-1030°C, and the spinning temperature to 860°C-920°C.

[0028] In order to realize the above-mentioned high-carbon steel wire smelting process, it is necessary to provide relevant working condition data in real time. Therefore, the present application also provides a smelting system for the high-carbon steel wire smelting process of the short-process electric furnace, which mainly includes electrodes, industrial cameras, rope encoders and several supersonic beam oxygen guns; the electrode is inserted into the electric furnace, and it is connected to the electrode lifting hydraulic cylinder through the electrode cross arm. The rope of the rope encoder is installed on the lifting hydraulic cylinder. When the electrode moves up and down in the electric furnace, the rope encoder can measure the height change of the electrode in real time; the industrial camera is installed on the iron adding side of the iron ladle for real-time monitoring of the iron adding condition; a supersonic beam oxygen gun is installed on both sides of the furnace door of the electric furnace, and the position deviating from the center relative to the center of the electric furnace is defined as the eccentric area, and a supersonic beam oxygen gun is installed in each eccentric area.

[0029] In the smelting process, since the oxygen consumption needs to be measured in real time, a mass flow meter, orifice flow meter, etc. can be used without special limitation.

[0030] Three specific application examples of the present invention are given below to verify the feasibility of the high carbon steel wire smelting process in a short-process electric furnace provided in the present application.

[0031] After the molten iron is desulfurized by KR, the weight of the molten iron and the silicon content of the molten iron are obtained from the database, and the oxygen supply required for this batch is calculated using the oxygen supply formula. The results provided by Examples 1 to 3 are shown in Table 1.

[0032] Table 1

[0033] The conditions of molten iron addition on the iron adding side, the change of electrode height, and the oxygen supply and consumption conditions in the electric furnace were obtained, and the electric furnace smelting process was divided into the scrap steel adding period, the iron adding period, the molten pool formation period, the melting temperature rising period, and the composition adjustment period, and the oxygen supply in different periods was adjusted, as shown in Table 2 (Example 1), Table 3 (Example 2), and Table 4 (Example 3). The lime consumption in the electric furnace smelting process was controlled at 30-35kg / t, and the secondary side voltage was controlled at 713V-900V during the power-on process.

[0034] Table 2

[0035] Table 3

[0036] Table 4

[0037] The final tapping temperature of electric furnace smelting, the final phosphorus, sulfur and nitrogen contents are shown in Table 5: Table 5

[0038] When the electric arc furnace is one-third of the way through, add low-nitrogen recarburizer to the ladle, add metallic manganese for pre-degassing, and add low-titanium and low-aluminum ferrosilicon. After the steel is tapped, add low-nitrogen recarburizer to the ladle and control the bottom blowing argon flow rate. The amount of recarburizer and alloy added during the steel tapping process, the amount of recarburizer added after the steel is tapped, and the bottom blowing control mode are shown in Table 6: Table 6

[0039] Temperature measurement and sampling, according to the composition of the molten steel sample and the requirements of the steel grade, add the remaining low-nitrogen carburizer, metallic manganese and low-titanium low-aluminum ferrosilicon to adjust the composition. After the composition is adjusted, the temperature of the molten steel is controlled in an appropriate range. Soft stirring is used to remove inclusions, and the argon blowing at the bottom of the ladle is gradually reduced to a soft stirring state, and the soft stirring time is controlled. The carburizer, alloy, molten steel temperature, soft stirring bottom blowing flow rate and soft stirring time are shown in Table 7: Table 7

[0040] Then enter the continuous casting machine casting process, the continuous casting machine is a straight arc rectangular billet continuous casting machine, the continuous casting billet section size is 300mm×390mm, the arc radius is 12.5m. Set the continuous casting tundish tonnage to 19t, the tundish tonnage to 35t during normal casting, and the tundish tonnage to 32t during continuous casting and changing tundishes. Control the superheat of the molten steel in the tundish to 28℃, and the continuous casting speed to 0.6m / min. The section reduction, reduction roller pressure, mold protective slag layer thickness, long water inlet argon flow, mold electromagnetic current, mold frequency, and mold water volume are shown in Table 8.

[0041] Table 8

[0042] The secondary cooling section adopts weak cooling mode, and the water volume of the secondary cooling section from zone 1 to zone 4 is: 80 NL / min in zone 1, 45 NL / min in zone 2, 30 NL / min in zone 3, and 25 NL / min in zone 4. In the process of blanking and rolling, the blanking heating temperature, rolling heating temperature, rolling temperature and wire laying temperature of 140 mm × 140 mm are set as shown in Table 9: Table 9

[0043] In summary, according to the division of the electric furnace smelting stages, the oxygen supply adjustment method for each stage is set to achieve precise control of the oxygen supply in the furnace, improve the molten pool stirring effect, accelerate the melting of waste, improve the dephosphorization effect, thereby improving the smelting efficiency and stabilizing the endpoint control.

[0044] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0045] The meaning of "and / or" described in this application means that the situations where each exists alone or both exist at the same time are included.

[0046] The term “connection” as used in this application may mean a direct connection between components or an indirect connection between components via other components.

[0047] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A short-process electric furnace high carbon steel wire smelting process, characterized in that: The following steps are involved: Step S1, KR molten iron pretreatment; Step S2, electric furnace smelting, select the factors affecting the oxygen supply of the electric furnace from the database, and use the least squares method to fit the required oxygen supply for the furnace to be smelted, where the influencing factors include the weight of the molten iron entering the furnace and the silicon content of the molten iron entering the furnace. The calculation formula for confirming the required oxygen supply for the furnace to be smelted is: , is the weight of molten iron entering the furnace, is the silicon content of molten iron entering the furnace, The oxygen supply required for the smelting furnace, in Nm 3 ; Obtain the molten iron addition conditions on the iron addition side, the electrode height change, and the oxygen supply and oxygen consumption conditions in the electric furnace, and divide the electric furnace smelting process into the scrap steel addition period, the iron addition period, the molten pool formation period, the melting temperature rise period, and the composition adjustment period; during the scrap steel addition period, the iron addition period, the molten pool formation period, the melting temperature rise period, and the composition adjustment period, adjust the oxygen supply timing and oxygen supply flow rate according to the oxygen supply curve; The end point composition and temperature control requirements of the steel to be smelted are determined from the database at the same time, and steel tapping begins when the determined control requirements are met; Step S3, LF refining, after the steel is tapped, the ladle is hoisted into the LF refining station to complete the temperature and composition adjustment, and the temperature of the molten steel is controlled within the set range; Step S4, casting of large square billets by continuous casting machine, protection casting during the whole continuous casting process, using low basicity and low alumina tundish covering agent, using low melting point crystallizer protection slag, and using crystallizer electromagnetic stirring; the second cooling section adopts weak cooling mode, and different water volumes are set in the four zones of the second cooling section; Step S5, blanking; Step S6, high-speed wire rolling.

2. The high carbon steel wire smelting process of the short process electric furnace according to claim 1, characterized in that: The endpoint composition of the steel to be smelted determined from the database includes, by mass fraction: C>0.04%, P<0.012%, S<0.012%; N<50ppm; endpoint temperature>1600℃.

3. The high carbon steel wire smelting process of the short process electric furnace according to claim 1, characterized in that: The charging amount of the electric furnace is controlled at 115t-118t, and the molten iron ratio is controlled at 25%-50%.

4. The high carbon steel wire smelting process of the short process electric furnace according to claim 1, characterized in that: The lime consumption range of the electric furnace smelting process is 30-35kg / t, and the secondary side voltage control range during the power-on process is 713V-900V.

5. The high carbon steel wire smelting process of the short process electric furnace according to claim 1, characterized in that: The chemical composition of the scrap steel added during the scrap steel adding period includes, by mass percentage: S≤0.005%, Ni≤0.01%, Cr≤0.03%, Cu≤0.01%, Al≤0.01%, and Ti≤0.01%.

6. The high carbon steel wire smelting process of the short process electric furnace according to claim 1, characterized in that: In step S2, The scrap steel adding period is defined as the time period from the addition of scrap steel to the start of power on, the iron adding period is defined as the time period from the start of power on to the completion of molten iron adding, the molten pool formation period is defined as the time period from the completion of molten iron adding to the drop in the electrode height to the lowest point, the melting temperature rising period is defined as the time period from the drop in the electrode height to the lowest point to the oxygen supply reaching 90% of the oxygen supply required for the smelting furnace, and the composition adjustment period is defined as the time period from the oxygen supply reaching 90% of the oxygen supply required for the smelting furnace to the end of smelting of the steel grade to be smelted; During the scrap steel adding period, set the main oxygen flow rate to 100-120Nm 3 / h, epoxy flow rate is 100-120 Nm 3 / h, coke oven gas flow rate is 80-100Nm 3 / h; During the iron addition period, set the main oxygen flow rate to 200-250Nm 3 / h, epoxy flow rate is 200-250 Nm 3 / h, coke oven gas flow rate is 400-500Nm 3 / h; During the molten pool formation period, set the main oxygen flow rate to 1000-1200Nm 3 / h, epoxy flow rate is 100-120 Nm 3 / h, coke oven gas flow rate is 100-120Nm 3 / h; During the melting and heating period, set the main oxygen flow rate to 1600-1800Nm 3 / h, epoxy flow rate is 100-120 Nm 3 / h, coke oven gas flow rate is 100-120Nm 3 / h; During the composition adjustment period, the main oxygen flow rate is 1400-1500Nm 3 / h, epoxy flow rate is 100-120 Nm 3 / h, coke oven gas flow rate is 100-120Nm 3 / h.

7. The high carbon steel wire smelting process of the short process electric furnace according to claim 1, characterized in that: When one third of the steel is discharged from the electric furnace, a low nitrogen carburizer is added, and metallic manganese and low titanium and low aluminum ferrosilicon are added for pre-deoxidation; during LF refining, the temperature of the molten steel is controlled at 1525℃-1535℃; After the temperature and composition are adjusted after LF refining, the argon gas at the bottom of the ladle is adjusted to a soft stirring state to remove inclusions. The argon gas flow rate is set to 60 NL / min -110NL / min, and the soft stirring time is set to 26min -31min.

8. The high carbon steel wire smelting process of the short process electric furnace according to claim 1, characterized in that: When using a large square billet continuous casting machine for casting, control the superheat of the molten steel in the tundish to 20℃-30℃; set the water volume of the crystallizer to 2975 L / min-3025L / min; The water volume in the four zones of the secondary cooling section is set to 60 NL / min -100 NL / min, 20 NL / min -50 NL / min, 20NL / min -40 NL / min, and 10 NL / min-30 NL / min respectively.

9. The high carbon steel wire smelting process of the short process electric furnace according to claim 1, characterized in that: In the blanking process, the blanking heating temperature is set to 1180°C-1250°C, and the blank is formed into 140mm×140mm; In the high-speed wire rolling process, the heating temperature is set to 1080℃-1160℃, the rolling start temperature is set to 960℃-1030℃, and the wire laying temperature is set to 860℃-920℃.

10. A smelting system for a high carbon steel wire smelting process in a short process electric furnace according to any one of claims 1 to 9, characterized in that: Including electrodes, industrial cameras, rope encoders and several supersonic beam oxygen guns; The electrode is inserted into the electric furnace and connected to the electrode lifting hydraulic cylinder through the electrode cross arm. The pull rope of the pull rope encoder is installed on the electrode lifting hydraulic cylinder. When the electrode moves up and down in the electric furnace, the pull rope encoder can measure the height change of the electrode in real time; Industrial cameras are installed on the iron-adding side of the ladle to monitor the iron-adding conditions in real time; A supersonic beam oxygen lance is installed on both sides of the furnace door of the electric furnace. The position deviated from the center relative to the center of the electric furnace is defined as an eccentric area, and a supersonic beam oxygen lance is installed in each eccentric area.

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