High-carbon steel wire short-process efficient low-cost electric furnace automatic power supply method, smelting process and smelting system

Abstract

The invention relates to a short-process efficient low-cost electric furnace automatic power supply method for high-carbon steel wires, a smelting process and a smelting system, the melting condition of waste steel is dynamically monitored through a pull rope encoder, and the smelting stage of an electric furnace is divided into a well penetrating stage, a melting stage, a heating stage and a temperature component adjusting stage by integrating the melting condition of the waste steel and the smelting power consumption condition; according to the dividing condition of the electric furnace smelting stages, the voltage gear and the current gear of each stage are set, so that accurate and efficient control over the electric furnace smelting process is achieved, the utilization rate of electric arc energy is improved, melting of scrap steel is accelerated, and the smelting efficiency is improved.

Description

Technical Field

[0001] The invention relates to a high-carbon steel wire short-process high-efficiency and low-cost electric furnace automatic power supply method, a smelting process and a smelting system, belonging to the technical field of smelting process, in particular to an electric furnace short-process smelting process. Background Art

[0002] In the existing high-carbon steel wire rod smelting process, the quality fluctuation of raw materials such as iron ore may affect the stability of product quality. With the long-term development of the steel industry, a large amount of scrap steel resources have accumulated in society. When the supply of scrap steel is stable enough and the price is competitive, enterprises find that the electric furnace short process with scrap steel as the main raw material is more attractive.

[0003] The scrap steel used in the short process of electric furnace has a relatively clear composition. With the cooperation of precise batching system, the quality of raw materials can be more easily controlled, thus ensuring the consistency of the quality of high-carbon steel wire products. At the same time, the short process of electric furnace has a fast heating speed and a short smelting cycle. Compared with traditional processes, it can complete the production of high-carbon steel wire faster, greatly improving the production efficiency and market competitiveness of enterprises.

[0004] For the electric furnace smelting process, the radiation energy generated by the arc when the power is turned on is the main source of scrap steel melting. Therefore, a reasonable power supply system is of great significance for improving smelting efficiency and reducing smelting power consumption. In the electric furnace smelting process, the power supply system is mainly adjusted by adjusting the transformer voltage gear and the arc current gear, and this operation basically relies on the furnace master's experience of the reaction state in the furnace. Patent CN109136462A provides a method for power supplying electric arc furnace smelting, in which the transformer gear is set mainly by the change of power supply time. Patent CN115537495A provides a power supply process for a large AC electric arc furnace, in which a reasonable power supply system is formulated according to different electricity prices and gross profit per ton of steel, thereby achieving the best economic benefits of electric arc furnace smelting. Patent CN116837176A provides a method and system for efficient power supply in the electric furnace smelting process, which adjusts the power supply system according to the noise changes at different stages in the electric arc furnace smelting process.

[0005] However, in the process of power supply for electric furnace smelting, the real-time melting state of scrap steel in the furnace and the reaction conditions in the furnace are crucial to the selection of the power supply system. The above-mentioned patents have failed to achieve real-time feedback on the conditions in the furnace, so it is impossible to guarantee whether the formulated power supply system can meet the actual needs of electric furnace smelting. Summary of the invention

[0006] In order to solve the problems in the background technology, the present invention provides a high-carbon steel wire short-process, high-efficiency, low-cost electric furnace automatic power supply method, smelting process and smelting system, which can optimize power supply for electric furnace smelting, shorten power supply time and reduce smelting power consumption.

[0007] The technical solution adopted by the present invention to solve its technical problem is: A high-carbon steel wire short-process high-efficiency and low-cost electric furnace automatic power supply method, after the molten iron passes through the KR treatment process, continues with the following steps: Step S1, determining from a database the weight of scrap steel entering the furnace, the weight of molten iron entering the furnace, the silicon content of the molten iron entering the furnace, the end point composition of the smelting steel grade, and the end point temperature in the current electric furnace process; Step S2, calculate the amount of electricity required in the electric furnace process according to the weight of the molten iron entering the furnace, the final tapping temperature of the electric furnace, and the silicon content of the molten iron entering the furnace. The calculation formula is: , is the power supply, in kWh, is the weight of molten iron entering the furnace, in units of t , The final tapping temperature of the electric furnace, in °C. is the silicon content of molten iron entering the furnace, unit is %; Step S3, starting the electric furnace to start smelting, dividing the electric furnace smelting process into four periods in sequence through the change of the electrode height and the measured smelting power consumption, namely, the well drilling period, the melting period, the heating period and the temperature component adjustment period, setting the power supply curve, and adjusting the voltage and current levels of the four periods; Among them, after entering the temperature composition adjustment period, the first temperature measurement sampling is carried out to measure and obtain the temperature T1 and the composition C1. Based on the endpoint composition and endpoint temperature of the smelting steel type determined in step S1, the power supply in the temperature composition adjustment period is adjusted according to the power supply curve, and the feeding is also adjusted at the same time, so that the endpoint composition and endpoint temperature meet the steelmaking standards.

[0008] Furthermore, in step S3, the time period from when the electrode height drops to the lowest point after power is applied is defined as the drilling period, the time period from when the drilling period ends to when the electrode height remains unchanged is defined as the melting period, and the power required from when the melting period ends to when the power consumption reaches 85% is defined as The time period is defined as the heating period, and the time period from the end of the heating period to the end of smelting is defined as the temperature composition adjustment period; The smelting end point temperature is ≥1600℃, and the end point components include, by mass percentage: C>0.04%, P<0.012%, S<0.012%, N<50ppm; Furthermore, during the drilling period, the transformer voltage gear adopts 10-12 gears, and the current gear adopts 5-7 gears; the secondary side voltage is controlled at 713V-835V, and the arc length is controlled at 478mm-512mm; Furthermore, during the melting period, the transformer voltage gear adopts 14-15 gears, and the current gear adopts 7-9 gears; the secondary side voltage is controlled at 871V-900V, and the arc length is controlled at 552mm-604mm; Furthermore, during the temperature rise period, the transformer voltage gear adopts 13-14 gears, and the current gear adopts 8-9 gears; the secondary side voltage is controlled at 843V-871V, and the arc length is controlled at 529mm-562mm; Furthermore, during the temperature component adjustment period, the transformer voltage gear adopts 12-13 gears, and the current gear adopts 8-9 gears; the secondary side voltage is controlled at 815V-843V, and the arc length is controlled at 494mm-529mm; Furthermore, in step S1, the chemical components of the scrap steel entering the furnace are, by mass percentage, S≤0.005%, Ni≤0.01%, Cr≤0.03%, Cu≤0.01%, Al≤0.01%, and Ti≤0.01%; Furthermore, in step S1, the control range of the electric furnace charge amount is 115t-118t, and the control range of the molten iron ratio is 25%-50%; Furthermore, in step S3, the oxygen consumption range of the electric furnace smelting process is 35-38Nm 3 / t, lime consumption range is 30-35kg / t; A high-carbon steel wire rod short-process high-efficiency and low-cost smelting process, after adopting the electric furnace automatic power supply method, continues with the following steps: Step S4, when the electric furnace has tapped one-third of the steel, a low-nitrogen carburizer is added, and a deoxidizer is added for pre-deoxidation. After the steel is tapped, the ladle is hoisted into the LF refining station for further adjustment of the temperature and composition, and the temperature range of the molten steel is controlled; Step S5, after the composition adjustment is completed in step S4, the argon gas is blown from the bottom of the ladle to a soft stirring state to remove inclusions; Step S6, using a large square billet continuous casting machine for casting, and protecting the casting throughout the continuous casting process; the second cooling section adopts a weak cooling mode, and the water volume of the second cooling section is set to 60 NL / min-100 NL / min in section 1, 20 NL / min-50 NL / min in section 2, 20 NL / min-40 NL / min in section 3, and 10 NL / min-30 NL / min in section 4; Step S7, blanking process, blanking into 140mm×140mm; Step S8, high-speed wire rolling process; Furthermore, in step S4, the added deoxidizer includes metallic manganese and low-titanium and low-aluminum ferrosilicon. After the composition adjustment is completed, the temperature of the molten steel is controlled to be in the range of 1525°C-1535°C; In step S5, the flow rate of the ladle bottom blowing argon gas is set in the range of 60NL / min-110NL / min, and the soft stirring time is set in the range of 26min-31min; In step S6, during the continuous casting full-process protection pouring, a low-basicity and low-alumina tundish covering agent is used, the superheat range of the molten steel in the tundish is controlled to be 20°C-30°C, a low-melting-point crystallizer protection slag is used, and the crystallizer electromagnetic stirring is used; the crystallizer water volume is set to 2975 L / min-3025 L / min; In step S7, the heating temperature range for blanking is set to 1180°C-1250°C; In step S8, during high-speed wire rolling, the heating temperature is 1080°C-1160°C, the rolling start temperature is 960°C-1030°C, and the wire laying temperature is 860°C-920°C; A high-carbon steel wire short-process high-efficiency and low-cost smelting system, used in the high-carbon steel wire short-process high-efficiency and low-cost electric furnace automatic power supply method, comprising electrodes, a pull rope encoder, and an electric energy meter; The electrode is fixed on the electrode cross arm through the electrode clamp, and the electrode cross arm is connected to the electrode lifting hydraulic cylinder drive. The draw rope of the draw rope encoder is installed on the hydraulic cylinder. When the electrode moves up and down in the electric furnace, the draw rope encoder can measure the height change of the electrode in real time. The electric energy meter is installed on the power supply line of the ladle, which can measure the current, voltage and power of the ladle, and then calculate the power consumption; Through the above technical solution, compared with the prior art, the present invention has the following beneficial effects: 1. The high-carbon steel wire short-process high-efficiency and low-cost electric furnace automatic power supply method provided by the present invention is based on the relationship between the amount of molten iron entering the furnace, the silicon content of the molten iron, the terminal temperature and other factors and the power supply, so that the error between the obtained power supply prediction value and the actual required power supply can be as small as possible, so as to more accurately determine the appropriate power supply according to various input conditions in the production process, and avoid insufficient power supply affecting the smelting efficiency or excessive power supply causing energy waste; 2. The high-carbon steel wire short-process high-efficiency and low-cost electric furnace automatic power supply method provided by the present invention has different melting states and required energy inputs for scrap steel at different smelting stages. The stages are divided according to the melting conditions of scrap steel and the smelting power consumption conditions. The power supply can be accurately controlled according to the characteristics of each stage, thereby improving the utilization of arc energy, accelerating the melting of scrap steel, and improving smelting efficiency. 3. The short-process, high-efficiency and low-cost smelting process for high-carbon steel wire provided by the present invention realizes dynamic analysis of the electric furnace smelting process based on the automatic power supply method of the electric furnace, and at the same time combines real-time monitoring and identification at different stages to realize efficient and accurate automatic control of the high-carbon steel smelting process; 4. The high-carbon steel wire short-process, efficient and low-cost smelting system provided by the present invention reflects the melting situation of scrap steel through the dynamic monitoring of the electrode lifting hydraulic cylinder by the pull-wire encoder, and can more accurately divide the electric furnace smelting stage. DETAILED DESCRIPTION

[0009] The specific dimensions used in the embodiments are only for illustrating the technical solution and do not limit the protection scope of the present invention.

[0010] High-performance, high-quality high-carbon steel wire products such as cord steel and spring steel have very high requirements for cleanliness, segregation, decarburization, surface quality, etc. The traditional blast furnace-converter long process requires a large amount of coke and other fuels, and has high energy consumption. The electric furnace short process mainly uses electricity. For high-carbon steel wire smelting, the electric furnace can melt and refine the scrap steel more efficiently when the scrap steel quality is good. At present, in the process of producing high-quality wire rods in the electric furnace short process, due to the lack of appropriate monitoring and feedback measures, the electric furnace smelting process is in a black box state, and the power supply of the electric furnace basically relies on manual experience for control. It is difficult for manual operation to accurately judge the smelting state of the electric furnace, resulting in problems such as long power-on time of the electric furnace, high smelting power consumption, and poor stability of the terminal temperature composition, which is not conducive to the stable control of product impurity elements, inclusions and composition.

[0011] In order to solve the above problems, the present application provides a high-carbon steel wire short-process, high-efficiency, low-cost electric furnace automatic power supply method, smelting process and smelting system. On the one hand, by dynamically monitoring the changes in electrode height during the electric furnace smelting process, the melting state of the scrap steel in the furnace is fed back; on the other hand, by analyzing the factors affecting power supply during the electric furnace smelting process, an energy input model is established; the electric furnace smelting stages are dynamically divided based on the results of the two aspects, and the voltage and current curves of each electric furnace smelting stage are set according to the division results, so as to achieve optimized power supply for electric furnace smelting, shorten the power supply time, and reduce smelting power consumption.

[0012] Among all the settings, the biggest innovation of this application is to provide a high-carbon steel wire short-process high-efficiency and low-cost electric furnace automatic power supply method, which is mainly used for the molten iron to continue the following steps after the KR treatment process: Step S1, first confirm that 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%; determine from the database the weight of the scrap steel entering the furnace, the weight of the molten iron entering the furnace, the silicon content of the molten iron entering the furnace, the end-point composition of the smelting steel grade and the end-point temperature in the current electric furnace process; regarding the end-point composition and end-point temperature of the smelting steel grade, for the steel grade of this application, select the smelting end-point temperature ≥1600℃, and the end-point components include, in mass percentage: C>0.04%, P<0.012%, S<0.012%, N<50ppm.

[0013] Clarifying the weight of scrap steel and molten iron entering the furnace from the database of historical data will help provide accurate reference for the batching of the electric furnace process according to the requirements and target output of different steel grades, and reasonably arrange the amount of scrap steel and molten iron added. The end temperature and composition directly affect the performance of steel. Through these data in the database, the difference between actual production and standard process requirements can be compared, and the cause of quality fluctuations can be discovered in time. Mastering the end steel tapping temperature of the electric furnace, the silicon content of the molten iron entering the furnace, and the end composition and temperature of the smelting steel grade is the key to ensuring product quality.

[0014] Regarding the scrap steel entering the furnace, based on the smelting steel type targeted by this application, the chemical components of the scrap steel entering the furnace, measured in mass percentage, include S≤0.005%, Ni≤0.01%, Cr≤0.03%, Cu≤0.01%, Al≤0.01%, and Ti≤0.01%.

[0015] Since the purpose of the application to optimize the power supply for electric furnace smelting is to provide energy to melt scrap steel and increase the temperature of molten steel, the three important factors that affect the overall energy balance are: the weight of molten iron entering the furnace, the final steel tapping temperature of the electric furnace, and the silicon content of the molten iron entering the furnace. In the next step S2, the amount of power required in the electric furnace process is calculated by the weight of molten iron entering the furnace, the final steel tapping temperature of the electric furnace, and the silicon content of the molten iron entering the furnace. The calculation formula is: , is the power supply, in kWh, is the weight of molten iron entering the furnace, in units of t , The final tapping temperature of the electric furnace, in °C. is the silicon content of the molten iron entering the furnace, in %; the above energy model is obtained by linear fitting using the least squares method. The basic idea of ​​the least squares method is to estimate the model parameters by minimizing the sum of squares of the residuals between the observed values ​​and the model predicted values. In electric furnace smelting, the relationship between the power supply and factors such as the amount of molten iron entering the furnace, the silicon content of the molten iron, and the terminal temperature is fitted, which can make the error between the predicted power supply and the actual power supply as small as possible.

[0016] After the energy model is calculated, the amount of power required for this furnace is sent to the PLC. The PLC controls the electrode to start electric furnace smelting, that is, step S3, starts the electric furnace to start smelting. Through the change of the electrode height and the measured smelting power consumption, the electric furnace smelting process is divided into four periods in sequence, namely, the well drilling period, the melting period, the heating period and the temperature component adjustment period. The power supply curve is set, and the voltage and current levels of the four periods are adjusted.

[0017] Regarding the setting of the four periods, the time period from the start of power-on to the electrode height dropping to the lowest point is defined as the drilling period, the time period from the end of the drilling period to the electrode maintaining a constant height is defined as the melting period, and the power required from the end of the melting period to the power consumption reaching 85% is defined as The time period is defined as the heating period, and the time period from the end of the heating period to the end of smelting is defined as the temperature and composition adjustment period.

[0018] Since the power supply system required for different stages of scrap steel melting in the electric furnace smelting process is quite different, it is necessary to ensure that the scrap steel melts quickly during the drilling period, so a power supply system with low voltage and high current is implemented. During the melting period, after the molten pool liquid level is formed in the furnace, the maximum power is required for power supply, so a high voltage, low current and long arc are implemented; during the heating period, after the scrap steel is melted, short arc operation is adopted to improve the arc energy utilization rate and ensure the heating effect.

[0019] Preferably, during the drilling period, the transformer voltage gear adopts 10-12 gears, and the current gear adopts 5-7 gears; the secondary side voltage is controlled at 713V-835V, and the arc length is controlled at 478mm-512mm. During the melting period, the transformer voltage gear adopts 14-15 gears, and the current gear adopts 7-9 gears; the secondary side voltage is controlled at 871V-900V, and the arc length is controlled at 552mm-604mm. During the heating period, the transformer voltage gear adopts 13-14 gears, and the current gear adopts 8-9 gears; the secondary side voltage is controlled at 843V-871V, and the arc length is controlled at 529mm-562mm.

[0020] After entering the temperature composition adjustment period, the first temperature measurement sampling is carried out to measure and obtain the temperature T1 and the composition C1. Based on the endpoint composition and the endpoint temperature of the smelting steel type determined in step S1, the power supply in the temperature composition adjustment period is adjusted according to the power supply curve, and the feeding is also adjusted. Specifically, the transformer voltage gear adopts 12-13 gears, and the current gear adopts 8-9 gears; the secondary side voltage is controlled at 815V-843V, and the arc length is controlled at 494mm-529mm, so that the endpoint composition and the endpoint temperature meet the steelmaking standards.

[0021] In the whole process of electric furnace smelting, oxygen consumption is controlled at 35-38Nm 3 / t, lime consumption is controlled at 30-35kg / t. By dynamically dividing the results of the electric furnace smelting stages, after setting the voltage and current curves of each electric furnace smelting stage, the optimized power supply of the electric furnace smelting is achieved, the scrap steel can be melted and refined quickly, the power supply time is shortened, and the arc energy utilization is improved at the same time, the scrap steel can be melted and refined more efficiently, and the smelting power consumption is reduced. The present application continues to provide a short-process, efficient and low-cost smelting process for high-carbon steel wire based on the above-mentioned electric furnace automatic power supply method. After adopting the electric furnace automatic power supply method, continue with the following steps: Step S4, when the electric furnace has tapped one-third of the steel, a low-nitrogen recarburizer is added, and metallic manganese and low-titanium, low-aluminum ferrosilicon are added for pre-deoxidation. After the steel is tapped, the ladle is hoisted into the LF refining station for further adjustment of the temperature and composition, and the temperature of the molten steel is controlled in the range of 1525℃-1535℃.

[0022] Step S5, after the composition adjustment is completed in step S4, soft stirring is performed to remove inclusions, and the argon gas blowing at the bottom of the ladle is gradually reduced to a soft stirring state. The reference flow rate setting range is 60NL / min-110NL / min. In the early stage, the slag surface fluctuation should be observed frequently. When the slag surface fluctuates slightly, the soft stirring time setting range is 26min-31min.

[0023] Step S6, adopt large square billet continuous casting machine for casting, protect casting throughout the continuous casting process, adopt low basicity and low alumina tundish covering agent, control the superheat range of molten steel in the tundish to 20℃-30℃, use low melting point crystallizer protective slag, and use crystallizer electromagnetic stirring; set the crystallizer water volume to 2975 L / min-3025L / min; adopt weak cooling mode in the second cooling section, and set the water volume of the second cooling section 1 to 60 NL / min-100 NL / min, section 2 to 20 NL / min-50 NL / min, section 3 to 20NL / min-40 NL / min, and section 4 to 10 NL / min-30 NL / min.

[0024] Step S7, the blanking process, sets the blanking heating temperature range to 1180°C-1250°C, and the blanks are opened into 140mm×140mm.

[0025] Step S8, high-speed wire rolling process, the heating temperature is 1080℃-1160℃, the rolling start temperature is 960℃-1030℃, and the wire laying temperature is 860℃-920℃.

[0026] In the process of explaining the automatic power supply method and smelting process of the short-process high-efficiency and low-cost electric furnace for high-carbon steel wire, another innovative point of the present application is also included throughout, which is the need to dynamically monitor the changes in the electrode height during the electric furnace smelting process, especially for the smelting state of the four periods of the well drilling period, the melting period, the heating period and the temperature component adjustment period. It is necessary to accurately judge, which is obviously impossible to do manually. Therefore, the present application also provides a high-carbon steel wire short-process high-efficiency and low-cost smelting system, including an electrode, a draw rope encoder and an electric energy meter. The electrode is inserted into the electric furnace and is fixed to the electrode cross arm by an electrode clamp. The electrode cross arm is connected to the electrode lifting hydraulic cylinder drive. The draw rope of the draw rope encoder is installed on the electrode hydraulic cylinder. When the electrode moves up and down in the ladle, the draw rope encoder can measure the height change of the electrode in real time; the electric energy meter is installed on the power supply line of the ladle, which can measure the current, voltage and power of the ladle, and then calculate the power consumption.

[0027] Three specific application examples of the present invention are given below to verify the feasibility of the short-process, efficient and low-cost smelting process for high-carbon steel wire provided in the present application.

[0028] After the molten iron is desulfurized by KR, the weight of the molten iron, the silicon content of the molten iron and the final tapping temperature of the electric furnace are obtained from the database, as shown in Table 1.

[0029] Table 1

[0030] Based on the data obtained from the database, the power consumption calculation formula is used to obtain the power consumption required for this furnace smelting, as shown in Table 2.

[0031] Table 2

[0032] Based on the change of electrode height and power consumption during the electric furnace smelting process, the electric furnace smelting stage is divided into the well drilling period, melting period, heating period and temperature component adjustment period, and the voltage and current gears of the four periods are adjusted, as shown in Table 3 (Example 1), Table 4 (Example 2) and Table 5 (Example 3). The oxygen consumption during the electric furnace smelting process is controlled at 35-38Nm 3 / t, lime consumption is controlled at 30-35kg / t, and the ratio of molten iron into the furnace is controlled at 25%-50%.

[0033] Table 3

[0034] Table 4

[0035] Table 5

[0036] The final tapping temperature of electric furnace smelting, the final phosphorus, sulfur and nitrogen contents are shown in Table 6: Table 6

[0037] When the electric arc furnace is one-third of the way through, add low-nitrogen recarburizer to the ladle, add metallic manganese for pre-deoxidation, 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 7: Table 7

[0038] After entering the refining process, add the remaining low-nitrogen carburizer, metallic manganese and low-titanium low-aluminum ferrosilicon to adjust the composition. After the composition is adjusted, control the temperature of the molten steel within an appropriate range. Soft stirring removes inclusions, gradually reduces the argon blowing at the bottom of the ladle to the soft stirring state, and controls the soft stirring time. The carburizer, alloy, molten steel temperature, soft stirring bottom blowing flow rate and soft stirring time are shown in Table 8: Table 8

[0039] 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 cross-sectional 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 molten steel superheat of 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 9 Table 9

[0040] 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 10: Table 10

[0041] In summary, the present application uses a rope encoder to dynamically monitor the melting of scrap steel, and divides the electric furnace smelting stage into the well drilling period, melting period, heating period and temperature component adjustment period based on the melting situation of the scrap steel and the smelting power consumption; according to the division of the electric furnace smelting stages, the voltage gear and current gear of each stage are set, so as to realize accurate and efficient control of the electric furnace smelting process, improve the utilization of arc energy, accelerate the melting of scrap steel, and improve the smelting efficiency.

[0042] 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.

[0043] 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.

[0044] The term “connection” as used in this application may mean a direct connection between components or an indirect connection between components via other components.

[0045] 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 high-carbon steel wire short-process high-efficiency and low-cost electric furnace automatic power supply method, characterized in that: After the molten iron has passed the KR treatment process, the following steps are continued: Step S1, determining from a database the weight of scrap steel entering the furnace, the weight of molten iron entering the furnace, the silicon content of the molten iron entering the furnace, the end point composition of the smelting steel grade, and the end point temperature in the current electric furnace process; Step S2, calculate the amount of electricity required in the electric furnace process according to the weight of the molten iron entering the furnace, the final tapping temperature of the electric furnace, and the silicon content of the molten iron entering the furnace. The calculation formula is: , is the power supply, in kWh, is the weight of molten iron entering the furnace, in units of t , The final tapping temperature of the electric furnace, in °C. is the silicon content of molten iron entering the furnace, unit is %; Step S3, starting the electric furnace to start smelting, dividing the electric furnace smelting process into four periods in sequence through the change of the electrode height and the measured smelting power consumption, namely, the well drilling period, the melting period, the heating period and the temperature component adjustment period, setting the power supply curve, and adjusting the voltage and current levels of the four periods; Among them, after entering the temperature composition adjustment period, the first temperature measurement sampling is carried out to measure and obtain the temperature T1 and the composition C1. Based on the endpoint composition and endpoint temperature of the smelting steel type determined in step S1, the power supply in the temperature composition adjustment period is adjusted according to the power supply curve, and the feeding is also adjusted at the same time, so that the endpoint composition and endpoint temperature meet the steelmaking standards.

2. The high-carbon steel wire short-process high-efficiency and low-cost electric furnace automatic power supply method according to claim 1 is characterized by: In step S3, the time period from the start of power-on to the time when the electrode height drops to the lowest point is defined as the drilling period, the time period from the end of the drilling period to the time when the electrode height remains unchanged is defined as the melting period, and the power consumption required from the end of the melting period to the power consumption reaching 85% is defined as The time period is defined as the heating period, and the time period from the end of the heating period to the end of smelting is defined as the temperature composition adjustment period; The smelting endpoint temperature is ≥1600°C. Calculated by mass percentage, the endpoint components include: C>0.04%, P<0.012%, S<0.012%, N<50ppm.

3. The high-carbon steel wire short-process high-efficiency and low-cost electric furnace automatic power supply method according to claim 2 is characterized by: During the drilling period, the transformer voltage gear uses 10-12 gears, and the current gear uses 5-7 gears; the secondary side voltage is controlled at 713V-835V, and the arc length is controlled at 478mm-512mm.

4. The high-carbon steel wire short-process high-efficiency and low-cost electric furnace automatic power supply method according to claim 2 is characterized by: During the melting period, the transformer voltage gear uses 14-15 gears, and the current gear uses 7-9 gears; the secondary side voltage is controlled at 871V-900V, and the arc length is controlled at 552mm-604mm.

5. The high-carbon steel wire short-process high-efficiency and low-cost electric furnace automatic power supply method according to claim 2 is characterized by: During the heating period, the transformer voltage gear adopts 13-14 gears, and the current gear adopts 8-9 gears; the secondary side voltage is controlled at 843V-871V, and the arc length is controlled at 529mm-562mm.

6. The high-carbon steel wire short-process high-efficiency and low-cost electric furnace automatic power supply method according to claim 2 is characterized by: During the temperature component adjustment period, the transformer voltage gear adopts 12-13 gears, and the current gear adopts 8-9 gears; the secondary side voltage is controlled at 815V-843V, and the arc length is controlled at 494mm-529mm.

7. The high-carbon steel wire short-process high-efficiency and low-cost electric furnace automatic power supply method according to claim 1 is characterized by: In step S1, the chemical components of the scrap steel entering the furnace, measured by mass percentage, include S≤0.005%, Ni≤0.01%, Cr≤0.03%, Cu≤0.01%, Al≤0.01%, and Ti≤0.01%.

8. The high carbon steel wire short process high efficiency and low cost electric furnace automatic power supply method according to claim 1, characterized in that; In step S1, the control range of the electric furnace charge amount is 115t-118t, and the control range of the molten iron ratio is 25%-50%.

9. The high carbon steel wire short process high efficiency and low cost electric furnace automatic power supply method according to claim 1, characterized in that; In step S3, the oxygen consumption range of the electric furnace smelting process is 35-38Nm 3 / t, lime consumption range is 30-35kg / t.

10. A short-process high-efficiency and low-cost smelting process for high-carbon steel wire, characterized in that: After adopting the electric furnace automatic power supply method of claim 1, continue with the following steps: Step S4, when the electric furnace has tapped one-third of the steel, a low-nitrogen carburizer is added, and a deoxidizer is added for pre-deoxidation. After the steel is tapped, the ladle is hoisted into the LF refining station for further adjustment of the temperature and composition, and the temperature range of the molten steel is controlled; Step S5, after the composition adjustment is completed in step S4, the argon gas blowing at the bottom of the ladle is adjusted to a soft stirring state to remove inclusions; Step S6, using a large square billet continuous casting machine for casting, and protecting the casting throughout the continuous casting process; the second cooling section adopts a weak cooling mode, and the water volume of the second cooling section is set to 60 NL / min-100 NL / min in section 1, 20 NL / min-50 NL / min in section 2, 20NL / min-40 NL / min in section 3, and 10 NL / min-30 NL / min in section 4; Step S7, blanking process, blanking into 140mm×140mm; Step S8, high-speed wire rolling process.

11. The high carbon steel wire rod short process with high efficiency and low cost according to claim 10, characterized in that: In step S4, the added deoxidizer includes metallic manganese and low-titanium and low-aluminum ferrosilicon. After the composition adjustment is completed, the temperature of the molten steel is controlled to be in the range of 1525°C-1535°C; In step S5, the flow rate of the ladle bottom blowing argon gas is set in the range of 60NL / min-110NL / min, and the soft stirring time is set in the range of 26min-31min; In step S6, during the continuous casting full-process protection pouring, a low-basicity and low-alumina tundish covering agent is used, the superheat range of the molten steel in the tundish is controlled to be 20°C-30°C, a low-melting-point crystallizer protection slag is used, and the crystallizer electromagnetic stirring is used; the crystallizer water volume is set to 2975 L / min-3025 L / min; In step S7, the heating temperature range for blanking is set to 1180°C-1250°C; In step S8, during high-speed wire rolling, the heating temperature is 1080°C-1160°C, the start rolling temperature is 960°C-1030°C, and the spinning temperature is 860°C-920°C.

12. A high-carbon steel wire rod short-process high-efficiency and low-cost smelting system, characterized by: Used in the high-carbon steel wire short-process high-efficiency and low-cost electric furnace automatic power supply method described in claim 1, comprising electrodes, a pull-wire encoder and an electric energy meter; The electrode is fixed on the electrode cross arm through the electrode clamp, and the electrode cross arm is connected to the electrode lifting hydraulic cylinder drive. The pull rope of the pull rope encoder is installed on the 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. The electric energy meter is installed on the power supply line of the electric furnace. It can measure the current, voltage and power when the electrodes are energized, and then calculate the power consumption.

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