High-carbon steel wire rod, smelting system and short-process efficient low-cost smelting method

Abstract

The invention relates to a high-carbon steel wire rod, a smelting system and a short-process high-efficiency low-cost smelting method. On the basis of real-time monitoring and identification at different stages of an electric furnace smelting process, a power supply curve, an oxygen supply curve and a charging and carbon spraying curve are formulated according to the characteristics of different stages of electric furnace smelting; and efficient and accurate automatic control over the electric furnace smelting process of the high-quality high-carbon steel wire is achieved.

Description

Technical Field

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

[0002] High-carbon steel wire products are diverse and widely used. High-quality high-carbon steel products represented by spring steel, cord steel, cable steel, etc. have very strict control requirements on cleanliness, segregation, surface and internal quality during the production process. Traditional high-quality high-carbon steel wire is generally produced by blast furnace-KR hot metal pretreatment-converter-refining (LF or LF-VD / RH)-continuous casting process. The production process is long, cleanliness and segregation control are difficult, and carbon emissions are high. With the gradual increase in the industry's demand for low-carbon emission products, the electric furnace short process is based on its unique advantages in carbon emissions, and the use of electric furnace short process to produce high-quality wire is gradually increasing.

[0003] For high-grade, important-purpose high-carbon steel wire products, impurity elements, inclusions, composition and uniformity of organization must meet strict requirements. Therefore, controlling the content of impurity elements, the type and size of inclusions, and the uniformity of composition and organization have always been the focus of the research and development of high-grade high-carbon steel wire. For example, patent CN117904530A provides a production method for 70-grade cord steel with a high scrap steel ratio in an electric furnace. By designing the charging, power-on, oxygen blowing and steel-tapping charging during the electric furnace smelting process under different scrap steel ratios, the production of 70-grade cord steel with a high scrap steel ratio is achieved. Patent CN114807727A provides a method for controlling the plasticization of cord steel inclusions and cord steel. By adding an alkali metal compound modifier during the steel-tapping process, the defects of poor deformation ability of inclusions, narrow industrial production control window and high control difficulty in the prior art are overcome, and the plasticization control of inclusions is achieved.

[0004] However, for high-carbon steel wire products, in addition to controlling impurity elements, inclusions, composition and uniformity of organization, it is also necessary to accurately and intelligently control the electric furnace smelting process and end point. In the process of producing high-quality wires 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. The energy input, slag addition and power supply and oxygen supply operations in the electric furnace production process rely on manual experience, and the process fluctuates greatly, resulting in poor stability of phosphorus, sulfur, oxygen content and temperature control at the end point of the electric furnace smelting, which is not conducive to the stable control of product impurity elements, inclusions and composition. Patent CN113215354A provides an electric furnace full scrap steel smelting process, in which the top-loading electric arc furnace smelting efficiency is improved by optimizing scrap steel batching, oxygen supply and power supply processes, but the process is mainly based on improving smelting efficiency and cannot be used to produce high-quality high-carbon steel wires with high impurity elements and cleanliness requirements.

[0005] Therefore, it is necessary to provide a smelting process for an electric furnace short process to solve the above problems. Summary of the invention

[0006] The present invention provides a high-carbon steel wire, a smelting system and a short-process, efficient and low-cost smelting method. On the basis of real-time monitoring and identification of different stages of the electric furnace smelting process, a power supply curve, an oxygen supply curve and a charging and carbon injection curve are formulated according to the characteristics of different stages of the electric furnace smelting, so as to realize efficient and accurate automatic control of the electric furnace smelting process of high-quality high-carbon steel wire.

[0007] The technical solution adopted by the present invention to solve the technical problem is: A high carbon steel wire rod comprising the following chemical components by mass percentage: C: 0.7%-0.9%, P≤0.015%, S≤0.012%, TO≤0.002%, N≤0.005%, Alt≤0.0015%, Ti≤0.0005%, Ni≤0.02%, Cu≤0.015%, Mo≤0.005%, Sn≤0.010% and As≤0.008%; Furthermore, in high carbon steel wire, SiO 2 -MnO-Al 2 O 3 Low melting point inclusions, inclusions greater than or equal to 1μm, the number density is ≤5 / mm 2 , the number density of inclusions greater than or equal to 5μm is ≤0.12 / mm 2 The maximum size of transverse inclusions is ≤15μm, the rating of longitudinal inclusions A, B, C, D, and Ds are all ≤1, and the size of brittle inclusions is ≤5μm.

[0008] A smelting system for smelting the high carbon steel wire, comprising electrodes, industrial cameras, infrared cameras, draw wire encoders, electric energy meters, carbon powder guns and several supersonic concentrated oxygen guns, The electrode is inserted into the electric furnace and fixed on the electrode cross arm through the electrode clamp. The electrode cross arm is connected to the electrode lifting hydraulic cylinder. The pull rope of the pull rope encoder is connected to 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. Install an infrared camera on the iron-adding side of the electric furnace to monitor the iron-adding condition in real time; install an industrial camera on the wall of the main control room to monitor the slag flow condition of the furnace door 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 electric furnace is powered on, and then calculate the power consumption; A carbon powder gun is installed on the furnace wall of the electric furnace to spray carbon powder into the furnace; A supersonic beam oxygen lance is installed on both sides of the furnace door of the electric furnace. The position of the steel tapping side of the electric furnace deviating from the center of the electric furnace is defined as the eccentric area, and a supersonic beam oxygen lance is installed in each eccentric area; A short-process, high-efficiency and low-cost smelting method, specifically comprising the following steps: Step S1, based on the chemical composition of the high carbon steel wire, continue to obtain 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, and the temperature control requirements; wherein the weight of the molten iron entering the furnace is controlled to be 20%-50% of the total weight; Step S2, based on the weight of the molten iron, the temperature control requirements and the silicon content of the molten iron obtained in step S1, the amount of electricity required for the smelting furnace to be smelted is calculated; based on the weight of the molten iron and the silicon content of the molten iron obtained in step S1, the amount of oxygen supply and the amount of lime added required for the smelting furnace to be smelted are calculated; Step S3, sending power supply, oxygen supply and lime addition amount to the smelting system, and performing electric furnace smelting through the PLC control of electrodes, supersonic concentrated oxygen lance and silo of the smelting system; Step S4, start the electric furnace to start smelting, and divide the electric furnace smelting process into a well drilling period, a melting period, a heating period and a temperature composition adjustment period by changing the height of the electrode inserted into the electric furnace and combining the measured smelting power consumption; divide the electric furnace smelting process into a scrap steel adding period, an iron adding period, a molten pool forming period, a melting and heating period and a temperature composition adjustment period by changing the height of the electrode inserted into the electric furnace and combining the molten iron adding condition on the iron adding side and the measured smelting oxygen consumption; divide the electric furnace smelting process into an iron adding start period, an iron adding end period, a furnace door slag flowing start period and a temperature composition adjustment period by combining the molten iron adding condition on the iron adding side and combining the furnace door slag flowing condition and the measured smelting power consumption; During the drilling period, melting period and heating period, the power supply curve is set and the voltage and current levels are adjusted; During the scrap steel adding period, iron adding period, molten pool forming period and melting temperature rising period, set the oxygen supply curve and adjust the oxygen lance flow rate; At the beginning and end of iron addition and the beginning of furnace door slag flow, set the carbon injection curve and adjust the amount of lime added; During the temperature composition adjustment period, temperature measurement and sampling are performed, and the voltage and current gears, oxygen lance flow rate and lime addition amount are adjusted according to the temperature control requirements and the chemical composition requirements of the steel grade and the power supply curve, oxygen supply curve and charging carbon injection curve; Step S5, when the end point composition and the end point temperature of the electric furnace smelting reach the steel tapping standard, steel tapping begins, a low nitrogen carburizer is added when one third of the steel is tapped from the electric furnace, and a deoxidizer is added for pre-deoxidation. After the steel tapping is completed, 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 S6, after the composition adjustment is completed at the LF refining station, the argon gas is blown from the bottom of the ladle to a soft stirring state to remove inclusions; Step S7, using a large square billet continuous casting machine for casting, protecting the casting throughout the continuous casting process, using a low-basicity and low-alumina tundish covering agent, and controlling the superheat of the molten steel in the tundish; the secondary cooling section adopts a weak cooling mode, and sets the water volume in each zone of the secondary cooling section; Step S8, blanking process; Step S9, high-carbon steel wire rolling process, obtaining high-carbon steel wire; Furthermore, in step S2, the calculation formula for the amount of electricity required in the electric furnace process is: , is the amount of electricity passed, 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 %; The calculation formula for the amount of oxygen required for the smelting furnace in the electric furnace process 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 ; The calculation formula for the lime required for the smelting furnace in the electric furnace process is: , is the weight of molten iron entering the furnace, is the silicon content of molten iron entering the furnace, The amount of lime required for the smelting furnace, in kg.

[0009] Further, in step S4, the drilling period is defined as the time period from the start of power-on when the electrode height drops to the lowest point, the melting period is defined as the time period from the end of the drilling period to the time when the electrode maintains a constant height, the heating period is defined as the time period from the end of the melting period to the time when the power consumption reaches 85% of the required power consumption, and the temperature component adjustment period is defined as the time period from the end of the heating period to the end of the smelting; The power supply curve is as follows: during the drilling period, the transformer voltage gear adopts 10-12 gears, and the current gear adopts 5-7 gears; during the melting period, the transformer voltage gear adopts 14-15 gears, and the current gear adopts 7-9 gears; during the heating period, the transformer voltage gear adopts 13-14 gears, and the current gear adopts 8-9 gears; during the temperature component adjustment period, the transformer voltage gear adopts 12-13 gears, and the current gear adopts 8-9 gears; Further, in step S4, 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 rising 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 temperature 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; The oxygen supply curve sets the main oxygen flow rate to 100-120Nm during the scrap steel addition period. 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 temperature rise 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 temperature 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; Further, in step S4, the iron addition start period is defined as the moment when the molten iron starts to flow out of the ladle opening, the iron addition end period is defined as the moment when the molten iron stops flowing out of the ladle opening, the furnace door slag flow start period is defined as the moment when the furnace door starts to flow out of the slag, and the temperature component adjustment period is defined as the moment when the power consumption is 85% of the required power supply; The carbon injection curve is as follows: at the beginning of iron addition, the amount of lime added is 10%-15% of the preset total amount of lime, and 400-500kg of light-burned dolomite is added; at the end of iron addition, the amount of lime added is 20%-25% of the preset total amount of lime, and 500-600kg of light-burned dolomite is added; at the beginning of furnace door slag flow, the amount of lime added is 45%-50% of the preset total amount of lime; during the temperature composition adjustment period, the preset remaining amount of lime is added; Furthermore, from the beginning of the furnace door slag flow period, when the furnace door slag flow height is lower than 1 / 3 of the furnace door height, carbon powder is sprayed into the furnace, and the carbon powder flow rate is maintained at 60-80kg / min; when the furnace door slag flow height is greater than 2 / 3 of the furnace door height, the carbon powder spraying is stopped; Furthermore, in step S5, the steel tapping standards include: end point temperature>1600°C, N<50ppm; end point components by mass fraction include: C>0.04%, P<0.012%, S<0.012%; During the steel-making process, the deoxidizers used for pre-deoxidation include metallic manganese and low-titanium and low-aluminum ferrosilicon; After the steel is tapped, the ladle is hoisted into the LF refining station for temperature and composition adjustment, and the temperature of the molten steel is controlled at 1525℃-1535℃; In step S6, the flow rate of argon gas blown from the bottom of the ladle is controlled at 60 NL / min-110 NL / min, and the soft stirring time is controlled at 26 min-31 min; Furthermore, in step S7, the continuous casting machine adopts a straight arc rectangular billet continuous casting machine, the cross-sectional size of the continuous casting billet is 300 mm×390 mm, and the arc radius is 12.5 m; the continuous casting speed is controlled at 0.5 m / min-0.7 m / min; When using a large square billet continuous casting machine for casting, the tonnage of the tundish for opening casting shall be ≥18t, the tonnage of the tundish for normal casting shall be ≥35t, the tonnage of the tundish for continuous casting and changing tundish shall be ≥30t, and the superheat of the molten steel in the tundish shall be controlled at 20℃-30℃; The continuous casting billet is lightly pressed in the tension and leveling machine, the total pressing amount is set to 8 mm -15 mm, and the pressing roller pressure is set to 30 bar -40 bar; Set the crystallizer electromagnetic stirring current to 400A-600A, the frequency to 5 Hz-7Hz, and the crystallizer water volume to 2975 L / min -3025 L / min; The secondary cooling section consists of four zones, and the water volumes of the four zones are 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; In step S8, the heating temperature for blanking is 1180°C-1250°C, and the blanking is made into 140mm×140mm; In step S9, the heating temperature of high-speed wire rolling is 1080°C-1160°C, the starting rolling temperature is 960°C-1030°C, and the spinning temperature is 860°C-920°C; Furthermore, the chemical components of the scrap steel entering the furnace include, by mass percentage, S≤0.005%, Ni≤0.01%, Cr≤0.03%, Cu≤0.01%, Al≤0.01%, and Ti≤0.01%.

[0010] Through the above technical solution, compared with the prior art, the present invention has the following beneficial effects: 1. The short-process, high-efficiency and low-cost smelting method provided by the present invention obtains the weight of the scrap steel to be smelted, the weight and composition of the molten iron to be smelted, the end composition of the smelting steel type, and the temperature control requirements from the database, and uses the energy model to preliminarily calculate the amount of electricity required for the furnace, accurately determine how much electricity is needed to complete the smelting process, and ensure the quality and production efficiency of the steel; 2. The short-process, high-efficiency and low-cost smelting method provided by the present invention realizes the dynamic analysis of the electric furnace smelting process, and reasonably divides the time period of the electric furnace smelting according to various working conditions in the smelting process, laying a foundation for the subsequent precise and efficient control of the electric furnace smelting process; 3. The short-process, high-efficiency and low-cost smelting method provided by the present invention formulates the power supply curve, oxygen supply curve and charging and carbon injection curve for each stage according to the division of the electric furnace smelting stages. The PLC directly controls the power supply, oxygen supply and charging operation according to the above curves, thereby realizing accurate and efficient control of the electric furnace smelting process; 4. The short-process, high-efficiency, and low-cost smelting method and smelting system provided by the present invention can be used to stably, efficiently, and low-cost produce high-purity, high-homogenization wire products, reduce the carbon emission level of the entire smelting process, and provide green raw materials for downstream industries.

[0011] The present invention is further described below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the short-process, high-efficiency and low-cost smelting method provided by the present invention. DETAILED DESCRIPTION

[0013] The present invention will now be described in further detail with reference to the accompanying drawings. 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.

[0014] As explained in the background technology, for the current short-process production of high-quality high-carbon steel wire in electric furnaces, attention should be paid to the precise and intelligent control of the electric furnace smelting process and end point, which is of great significance for achieving stable performance of high-quality high-carbon steel wire and efficient and low-cost production.

[0015] If we want to solve the problem of the electric furnace smelting process being in a "black box", we must properly monitor and feedback the entire short-process smelting process, and conduct dynamic analysis of the electric furnace smelting process in a timely manner. As the innovation of this application, it is based on the type of high-carbon steel wire that needs to be smelted and the real-time monitoring and identification of different stages of the electric furnace smelting process, and formulates the power supply curve, oxygen supply curve and feeding carbon injection curve according to the characteristics of different stages of electric furnace smelting, so as to achieve efficient and accurate automatic control of the electric furnace smelting process of high-quality high-carbon steel wire.

[0016] First, the present application is to determine the composition and various standard requirements of high-carbon steel wire smelted by a short-process, efficient and low-cost smelting method. In addition to Si, Mn, Cr, V alloy elements and Fe elements, the high-carbon steel wire also includes the following chemical components by mass percentage: C: 0.7%-0.9%, P≤0.015%, S≤0.012%, TO≤0.002%, N≤0.005%, Alt≤0.0015%, Ti≤0.0005%, Ni≤0.02%, Cu≤0.015%, Mo≤0.005%, Sn≤0.010% and As≤0.008%. The high-carbon steel wire that meets the standard requirements is mainly SiO 2 -MnO-Al 2 O 3 Low melting point inclusions, inclusions greater than or equal to 1μm, the number density is ≤5 / mm 2 , the number density of inclusions greater than or equal to 5μm is ≤0.12 / mm 2 The maximum size of transverse inclusions is ≤15μm, the rating of longitudinal inclusions A, B, C, D, and Ds are all ≤1, and the size of brittle inclusions is ≤5μm.

[0017] After determining the high-carbon steel wire to be prepared, it is necessary to develop corresponding curves according to the characteristics of different stages of smelting, so a series of monitoring and identification equipment needs to be installed. The smelting system used for the short-process, high-efficiency and low-cost smelting method in this application includes electrodes, industrial cameras, infrared cameras, rope encoders, electric energy meters, carbon powder guns and several supersonic beam oxygen guns. 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 rope of the rope encoder is connected to the electrode lifting hydraulic cylinder. When the electrode moves up and down in the electric furnace, the rope encoder is connected to the electrode lifting hydraulic cylinder. The encoder can measure the height change of the electrode in real time; an infrared camera is installed on the iron adding side of the electric furnace to monitor the iron adding condition in real time; an industrial camera is installed on the wall of the main control room to monitor the slag flow condition of the furnace door in real time; an electric energy meter is installed on the power supply line of the electric furnace, which can measure the current, voltage and power of the ladle, and then calculate the power consumption; a carbon powder gun is installed on the wall of the electric furnace to spray carbon powder into the furnace; a supersonic beam oxygen gun is installed on both sides of the furnace door of the electric furnace, and the position of the steel tapping side of the electric furnace deviating from the center of the electric furnace is defined as the eccentric area, and a supersonic beam oxygen gun is installed in each eccentric area.

[0018] Of course, in the smelting system, PLC is needed for comprehensive control, so the control part also includes memory, processor and controller. The memory is used to receive and store the collected scrap steel, molten iron, steel temperature, composition, electrode height, furnace door slag flow and iron addition, etc. The computer program is set in the processor, and the subsequent short-process high-efficiency and low-cost smelting method is fully controlled through the controller. It should be noted that the power supply curve, oxygen supply curve and charging carbon injection curve formulated at each stage can be independently controlled by PLC without interfering with each other.

[0019] Next, a short-process, high-efficiency and low-cost smelting method provided by this application is described in detail. Figure 1 As shown, the specific steps include: Step S1, based on the chemical composition of the high carbon steel wire, continue to obtain from the database the weight of the scrap steel entering the furnace to be smelted, the weight of the molten iron entering the furnace, the silicon content of the molten iron entering the furnace, and the temperature control requirements, wherein the weight of the molten iron entering the furnace is controlled to be 20%-50% of the total weight. The preferred chemical components of the scrap steel entering the furnace include, by mass percentage: S≤0.005%, Ni≤0.01%, Cr≤0.03%, Cu≤0.01%, Al≤0.01%, and Ti≤0.01%.

[0020] Step S2, based on the weight of the molten iron entering the furnace, the temperature control requirements and the silicon content of the molten iron entering the furnace obtained in step S1, calculate the amount of power required for the furnace to be smelted; based on the weight of the molten iron entering the furnace and the silicon content of the molten iron entering the furnace obtained in step S1, calculate the amount of oxygen supply and the amount of lime added for the furnace to be smelted.

[0021] This step is to obtain information from the database and use the model to calculate the amount of power and oxygen required for this furnace smelting, which also lays a solid foundation for the subsequent formulation of the corresponding curve.

[0022] Specifically, the calculation formula for the amount of electricity required in the electric furnace process is: , is the amount of electricity passed, 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 %; The calculation formula for the amount of oxygen required for the smelting furnace in the electric furnace process 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 ; The calculation formula for the lime required for the smelting furnace in the electric furnace process is: , is the weight of molten iron entering the furnace, is the silicon content of molten iron entering the furnace, The amount of lime required for the smelting furnace, in kg.

[0023] After the model is calculated in step S2, the power supply, oxygen supply and lime addition amount required for this furnace are sent to the PLC. The PLC controls the electrodes, supersonic beam oxygen lance and silo in the smelting system to automatically adjust the voltage and current gears, oxygen lance flow, lime addition amount and carbon injection. The control setting is step S3, which is an important innovation of the present application. The electric furnace is started to start smelting. By changing the height of the electrode inserted into the electric furnace and combining the measured smelting power consumption, the electric furnace smelting process is divided into a drilling period, a melting period, a heating period and a temperature composition adjustment period; by changing the height of the electrode inserted into the electric furnace and combining the molten iron adding condition on the iron adding side and the measured smelting oxygen consumption, the electric furnace smelting process is divided into a scrap steel adding period, an iron adding period, a molten pool formation period, a melting and heating period and a temperature composition adjustment period; by the molten iron adding condition on the iron adding side, combined with the furnace door slag flowing condition and the measured smelting power consumption, the electric furnace smelting process is divided into an iron adding start period, an iron adding end period, a furnace door slag flowing start period and a temperature composition adjustment period.

[0024] Within each period after the above classification, the control of each curve is implemented. Specifically, during the drilling period, melting period and heating period, the power supply curve is set to adjust the voltage and current gears; during the scrap steel adding period, iron adding period, molten pool formation period and melting and heating period, the oxygen supply curve is set to adjust the oxygen gun flow rate; during the iron adding start period, iron adding end period and furnace door slag flow start period, the charging and carbon injection curve is set to adjust the amount of lime added.

[0025] For the power supply curve, the drilling period is defined as the time period from the start of power-on when the electrode height drops to the lowest point, the melting period is defined as the time period from the end of the drilling period to the time when the electrode maintains a constant height, the heating period is defined as the time period from the end of the melting period to the time when the power consumption is 85% of the required amount of power, and the temperature component adjustment period is defined as the time period from the end of the heating period to the end of the smelting end; for the power supply curve, in the drilling period, the transformer voltage gear adopts 10-12 gears, and the current gear adopts 5-7 gears; in the melting period, the transformer voltage gear adopts 14-15 gears, and the current gear adopts 7-9 gears; in the heating period, the transformer voltage gear adopts 13-14 gears, and the current gear adopts 8-9 gears; in the temperature component adjustment period, the transformer voltage gear adopts 12-13 gears, and the current gear adopts 8-9 gears.

[0026] For the oxygen supply curve, 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 temperature 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 to be smelted; in the scrap steel adding period of the oxygen supply curve, 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 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 temperature rise 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 temperature 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.

[0027] For the charging and carbon spraying curve, the iron addition start period is defined as the moment when molten iron starts to flow out of the ladle, the iron addition end period is defined as the moment when molten iron stops flowing out of the ladle, the furnace door slag flow start period is defined as the moment when slag starts to flow out of the furnace door, and the temperature composition adjustment period is defined as the moment when the power consumption is 85%; for the charging and carbon spraying curve, at the beginning of iron addition, the amount of lime added is 10%-15% of the preset total amount of lime, and 400-500kg of light-burned dolomite is added; at the end of iron addition, the amount of lime added is the preset amount of lime. Assuming that the total amount of lime is 20%-25%, add 500-600kg of light-burned dolomite; at the beginning of slag flow at the furnace door, add 45%-50% of the preset total amount of lime; during the temperature composition adjustment period, add the preset remaining amount of lime; from the beginning of slag flow at the furnace door, when the slag flow height of the furnace door is lower than 1 / 3 of the furnace door height, spray carbon powder into the furnace, and the carbon powder flow rate is maintained at 60-80kg / min; when the slag flow height of the furnace door is greater than 2 / 3 of the furnace door height, stop spraying carbon powder.

[0028] It should be noted that when controlling and adjusting, the setting period of the three curves also includes the temperature composition adjustment period. During this period, the subsequent steelmaking operation needs to be taken into consideration. Therefore, during the temperature composition adjustment period, the first temperature measurement sampling is started. The measured temperature is T1 and the composition C1. According to the endpoint temperature and the chemical composition requirements of the steel grade, the voltage and current gears, oxygen gun flow rate and lime addition amount are adjusted according to the power supply curve, oxygen supply curve and charging and carbon injection curve.

[0029] Step S4, when the end point composition and end point temperature of the electric furnace smelting reach the steel-making standard: the end point temperature>1600°C, N<50ppm; the end point composition by mass fraction includes: C>0.04%, P<0.012%, S<0.012%; start tapping, add low nitrogen carburizer when one-third of the steel is tapped from the electric furnace, and add metallic manganese and low titanium and low aluminum ferrosilicon for pre-deoxidation. After the steel-making is completed, 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°C-1535°C.

[0030] Step S5, after the composition adjustment is completed at the LF refining station, 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, with a reference flow rate of 60 NL / min -110NL / min. In the early stage, the fluctuation of the slag surface should be frequently observed, and the soft stirring time should be controlled at 26min -31min when the slag surface fluctuates slightly.

[0031] Step S6, the continuous casting machine adopts a straight arc rectangular billet continuous casting machine, the cross-sectional size of the continuous casting billet is 300mm×390mm, and the arc radius is 12.5m; the continuous casting pulling speed is controlled at 0.5m / min-0.7m / min; when the large square billet continuous casting machine is used for casting, the continuous casting is protected throughout the casting process, and a low-basicity and low-alumina tundish covering agent is used. The tundish opening tonnage is ≥18t, the tundish tonnage is ≥35t during normal casting, and the tundish tonnage is ≥30t during continuous casting and changing tundishes. The superheat of the molten steel in the tundish is controlled to be 20℃-30℃; the continuous casting billet is lightly pressed in the straightening machine, the total pressing amount is set to 8mm-15mm, and the pressing roller pressure is set to 30bar-40bar; a low melting point crystallizer protective slag is used, and the crystallizer electromagnetic stirring is used at the same time, and the crystallizer electromagnetic stirring current is set to 400A-600A, the frequency is 5Hz-7Hz, and the crystallizer water volume is 2975 L / min-3025L / min; the secondary cooling section consists of four zones, and the water volume of the four zones is set to 60 NL / min -100 NL / min, 20 NL / min -50 NL / min, 20 NL / min -40 NL / min, and 10NL / min-30 NL / min respectively.

[0032] Step S7, the blanking process, the blanking heating temperature is 1180℃-1250℃, and the blanks are opened into 140mm×140mm.

[0033] Step S8, high carbon steel wire rolling process, setting the heating temperature to 1080°C-1160°C, the rolling start temperature to 960°C-1030°C, and the wire laying temperature to 860°C-920°C to obtain high carbon steel wire.

[0034] This application continues to provide a specific case to verify the feasibility and superiority of the short-process, high-efficiency and low-cost smelting method.

[0035] The weight of molten iron entering the furnace, the silicon content of molten iron entering the furnace and the final tapping temperature of the electric furnace are obtained from the database, as shown in Table 1.

[0036] Table 1 Hot metal information

[0037] Based on the data obtained from the database, the power supply, oxygen supply and lime addition amount required for this furnace smelting are obtained using the power supply calculation formula, oxygen supply calculation formula and lime addition calculation formula, as shown in Table 2.

[0038] Table 2 Power supply, oxygen supply and lime addition amount of the furnace to be smelted

[0039] Based on the changes in electrode height and power consumption during the electric furnace smelting process, the electric furnace smelting stages are divided into drilling period, melting period, heating period and temperature composition adjustment period, and the voltage and current gears of the four periods are adjusted, as shown in Table 3; the molten iron adding conditions on the iron adding side, the changes in electrode height and the oxygen supply and consumption conditions in the electric furnace are obtained, and the electric furnace smelting process is divided into scrap steel adding period, iron adding period, molten pool formation period, melting and heating period and composition adjustment period, and the oxygen supply in different periods is adjusted, as shown in Table 4; through the molten iron adding conditions on the iron adding side, combined with the slag flow conditions of the furnace door and the measured smelting power consumption, the electric furnace smelting process is divided into the iron adding start period, iron adding end period, furnace door slag flow start period and temperature composition adjustment period, and the amount of lime added in different periods is adjusted, as shown in Table 5.

[0040] Table 3 Power supply curve settings for the smelting process

[0041] Table 4 Oxygen supply curve setting during smelting process

[0042] Table 5 Setting of charging curve in smelting process

[0043] The final tapping temperature of electric furnace smelting, the final phosphorus, sulfur and nitrogen contents are shown in Table 6: Table 6 End point of electric furnace smelting

[0044] 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 Feeding conditions during steel tapping

[0045] 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 8: Table 8 Refining process operation

[0046] 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 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 Operation of continuous casting process

[0047] 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 Rolling process operation

[0048] Finally, the example of high carbon steel wire is obtained as shown in Table 11.

[0049] Table 11 Inclusions in high carbon steel wire

[0050] Through the above-mentioned smelting method, the energy input, slag addition, power supply and oxygen supply operations can be automatically and accurately controlled during the electric furnace production process, so that the phosphorus, sulfur, oxygen content and temperature control at the end of the electric furnace smelting are relatively stable, and ultimately the product impurity elements, inclusions and components can be stably controlled.

[0051] 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.

[0052] 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.

[0053] The term “connection” as used in this application may mean a direct connection between components or an indirect connection between components via other components.

[0054] 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, characterized in that: The chemical composition includes the following by mass percentage: C: 0.7%-0.9%, P≤0.015%, S≤0.012%, TO≤0.002%, N≤0.005%, Alt≤0.0015%, Ti≤0.0005%, Ni≤0.02%, Cu≤0.015%, Mo≤0.005%, Sn≤0.010% and As≤0.008%.

2. The high carbon steel wire according to claim 1, characterized in that: In high carbon steel wire, the main inclusions are SiO2-MnO-Al2O3 low melting point inclusions, and the number density of inclusions greater than or equal to 1μm is ≤5 / mm 2 , the number density of inclusions greater than or equal to 5μm is ≤0.12 / mm 2 The maximum size of transverse inclusions is ≤15μm, the rating of longitudinal inclusions A, B, C, D, and Ds are all ≤1, and the size of brittle inclusions is ≤5μm.

3. A smelting system, characterized in that: Used for smelting the high carbon steel wire described in claim 2, comprising electrodes, industrial cameras, infrared cameras, pull-wire encoders, electric energy meters, carbon powder guns, and several supersonic concentrated oxygen guns; The electrode is inserted into the electric furnace and fixed on the electrode cross arm through the electrode clamp. The electrode cross arm is connected to the electrode lifting hydraulic cylinder. The pull rope of the pull rope encoder is connected to 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. Install an infrared camera on the iron-adding side of the electric furnace to monitor the iron-adding condition in real time; install an industrial camera on the wall of the main control room to monitor the slag flow condition of the furnace door 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 electric furnace is powered on, and then calculate the power consumption; A carbon powder gun is installed on the furnace wall of the electric furnace to spray carbon powder into the furnace; A supersonic beam oxygen lance is installed on both sides of the furnace door of the electric furnace. The position of the steel-outlet side of the electric furnace deviating from the center of the electric furnace is defined as the eccentric area, and a supersonic beam oxygen lance is installed in each eccentric area.

4. A short-process, high-efficiency and low-cost smelting method, characterized in that: The specific steps include: Step S1, based on the chemical composition of the high carbon steel wire rod according to claim 1, continue to obtain 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, and the temperature control requirements; wherein the weight of the molten iron entering the furnace is controlled to be 20%-50% of the total weight; Step S2, based on the weight of the molten iron, the temperature control requirements and the silicon content of the molten iron obtained in step S1, the amount of electricity required for the smelting furnace is calculated; based on the weight of the molten iron and the silicon content of the molten iron obtained in step S1, the amount of oxygen supply and the amount of lime added required for the smelting furnace are calculated; Step S3, sending power supply, oxygen supply and lime addition amount to the smelting system according to claim 3, and performing electric furnace smelting through the PLC control electrodes, supersonic concentrated oxygen lance and silo of the smelting system; Step S4, start the electric furnace to start smelting, and divide the electric furnace smelting process into a well drilling period, a melting period, a heating period and a temperature composition adjustment period by changing the height of the electrode inserted into the electric furnace and combining the measured smelting power consumption; divide the electric furnace smelting process into a scrap steel adding period, an iron adding period, a molten pool forming period, a melting and heating period and a temperature composition adjustment period by changing the height of the electrode inserted into the electric furnace and combining the molten iron adding condition on the iron adding side and the measured smelting oxygen consumption; divide the electric furnace smelting process into an iron adding start period, an iron adding end period, a furnace door slag flowing start period and a temperature composition adjustment period by combining the molten iron adding condition on the iron adding side and combining the furnace door slag flowing condition and the measured smelting power consumption; During the drilling period, melting period and heating period, the power supply curve is set and the voltage and current levels are adjusted; During the scrap steel adding period, iron adding period, molten pool forming period and melting temperature rising period, set the oxygen supply curve and adjust the oxygen lance flow rate; At the beginning and end of iron addition and the beginning of furnace door slag flow, set the carbon injection curve and adjust the amount of lime added; During the temperature composition adjustment period, temperature measurement and sampling are performed, and the voltage and current gears, oxygen lance flow rate and lime addition amount are adjusted according to the temperature control requirements and the chemical composition requirements of the steel grade and the power supply curve, oxygen supply curve and charging carbon injection curve; Step S5, when the end point composition and the end point temperature of the electric furnace smelting reach the steel tapping standard, steel tapping begins, a low nitrogen carburizer is added when one third of the steel is tapped from the electric furnace, and a deoxidizer is added for pre-deoxidation. After the steel tapping is completed, 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 S6, after the composition adjustment is completed at the LF refining station, the argon gas is blown from the bottom of the ladle to a soft stirring state to remove inclusions; Step S7, using a large square billet continuous casting machine for casting, protecting the casting throughout the continuous casting process, using a low-basicity and low-alumina tundish covering agent, and controlling the superheat of the molten steel in the tundish; the secondary cooling section adopts a weak cooling mode, and sets the water volume in each zone of the secondary cooling section; Step S8, blanking process; Step S9, high-carbon steel wire rolling process, to obtain high-carbon steel wire.

5. The short-process high-efficiency and low-cost smelting method according to claim 4 is characterized in that: In step S2, the calculation formula for the amount of electricity required in the electric furnace process is: , is the amount of electricity passed, 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 %; The calculation formula for the amount of oxygen required for the smelting furnace in the electric furnace process 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 ; The calculation formula for the lime required for the smelting furnace in the electric furnace process is: , is the weight of molten iron entering the furnace, is the silicon content of molten iron entering the furnace, The amount of lime required for the smelting furnace, in kg.

6. The short-process high-efficiency and low-cost smelting method according to claim 4 is characterized in that: In step S4, the drilling period is defined as the time period from the start of power-on when the electrode height drops to the lowest point, the melting period is defined as the time period from the end of the drilling period to the time when the electrode height remains unchanged, the heating period is defined as the time period from the end of the melting period to the time when the power consumption reaches 85% of the required power consumption, and the temperature component adjustment period is defined as the time period from the end of the heating period to the end of the smelting. According to the power supply curve, during the drilling period, the transformer voltage gear adopts 10-12 gears, and the current gear adopts 5-7 gears; during the melting period, the transformer voltage gear adopts 14-15 gears, and the current gear adopts 7-9 gears; during the heating period, the transformer voltage gear adopts 13-14 gears, and the current gear adopts 8-9 gears; during the temperature component adjustment period, the transformer voltage gear adopts 12-13 gears, and the current gear adopts 8-9 gears.

7. The short-process high-efficiency and low-cost smelting method according to claim 4 is characterized in that: In step S4, 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 rising 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 temperature 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; The oxygen supply curve sets the main oxygen flow rate to 100-120Nm during the scrap steel addition period. 3 / h, epoxy flow rate is 100-120Nm 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 temperature rise 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 temperature 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.

8. The short-process, high-efficiency and low-cost smelting method according to claim 4 is characterized in that: In step S4, the iron addition start period is defined as the moment when the molten iron starts to flow out of the ladle opening, the iron addition end period is defined as the moment when the molten iron stops flowing out of the ladle opening, the furnace door slag flow start period is defined as the moment when the furnace door starts to flow out of the slag, and the temperature component adjustment period is defined as the moment when the power consumption is 85% of the required power supply; According to the charging and carbon injection curve, at the beginning of iron addition, the amount of lime added is 10%-15% of the preset total amount of lime, and 400-500kg of light-burned dolomite is added; at the end of iron addition, the amount of lime added is 20%-25% of the preset total amount of lime, and 500-600kg of light-burned dolomite is added; at the beginning of slag flow at the furnace door, the amount of lime added is 45%-50% of the preset total amount of lime; during the temperature composition adjustment period, the preset remaining amount of lime is added.

9. The short-process high-efficiency and low-cost smelting method according to claim 8, characterized in that: From the beginning of slag flow from the furnace door, when the slag flow height of the furnace door is lower than 1 / 3 of the furnace door height, carbon powder is sprayed into the furnace, and the carbon powder flow rate is maintained at 60-80kg / min; when the slag flow height of the furnace door is greater than 2 / 3 of the furnace door height, stop spraying carbon powder.

10. The short-process high-efficiency and low-cost smelting method according to claim 4, characterized in that: In step S5, the steel tapping standards include: end point temperature>1600°C, N<50ppm; end point components by mass fraction include: C>0.04%, P<0.012%, S<0.012%; During the steel-making process, the deoxidizers used for pre-deoxidation include metallic manganese and low-titanium and low-aluminum ferrosilicon; After the steel is tapped, the ladle is hoisted into the LF refining station for temperature and composition adjustment, and the temperature of the molten steel is controlled at 1525℃-1535℃; In step S6, the flow rate of argon gas blown from the bottom of the ladle is controlled at 60 NL / min-110 NL / min, and the soft stirring time is controlled at 26 min-31 min.

11. The short-process high-efficiency and low-cost smelting method according to claim 4, characterized in that: In step S7, the continuous casting machine adopts a straight arc rectangular billet continuous casting machine, the cross-sectional size of the continuous casting billet is 300 mm×390 mm, and the arc radius is 12.5 m; the continuous casting speed is controlled at 0.5 m / min-0.7 m / min; When using a large square billet continuous casting machine for casting, the tonnage of the tundish for opening casting shall be ≥18t, the tonnage of the tundish for normal casting shall be ≥35t, the tonnage of the tundish for continuous casting and changing tundish shall be ≥30t, and the superheat of the molten steel in the tundish shall be controlled at 20℃-30℃; The continuous casting billet is lightly pressed in the tension and leveling machine, the total pressing amount is set to 8 mm-15 mm, and the pressing roller pressure is set to 30 bar-40 bar; Set the crystallizer electromagnetic stirring current to 400A-600A, the frequency to 5 Hz-7Hz, and the crystallizer water volume to 2975 L / min-3025 L / min; The secondary cooling section consists of four zones, and the water volumes of the four zones are set to 60 NL / min-100 NL / min, 20 NL / min-50NL / min, 20 NL / min-40 NL / min, and 10 NL / min-30 NL / min in sequence; In step S8, the heating temperature for blanking is 1180°C-1250°C, and the blanking is made into 140mm×140mm; In step S9, the heating temperature of high-speed wire rolling is 1080°C-1160°C, the starting rolling temperature is 960°C-1030°C, and the spinning temperature is 860°C-920°C.

12. The short-process, high-efficiency and low-cost smelting method according to claim 4, characterized in that: The chemical components of the scrap steel entering the furnace, in terms of mass percentage, include: S≤0.005%, Ni≤0.01%, Cr≤0.03%, Cu≤0.01%, Al≤0.01%, and Ti≤0.01%.

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