Preparation device of high-strength prestressed steel wire and use method of preparation device

Abstract

The invention relates to the technical field of steel wire preparation, in particular to a high-strength prestressed steel wire preparation device and a use method thereof.The device comprises a pay-off mechanism, a pretreatment unit, a drawing mechanism, a heat treatment furnace, a cooling device, a stress applying mechanism, an online stress detector and a take-up mechanism; the stress applying mechanism comprises a tension roller set driven by a servo motor, a hydraulic damper and an on-line stress detector, and the on-line stress detector monitors the strain of a steel wire in real time through an optical fiber strain sensor and is linked with the PLC control system; dynamic prestress control and a multi-stage heat treatment process work cooperatively, so that the tensile strength of the steel wire stably reaches 1570 MPa or above, a closed-loop control tension system and an online detection technology are adopted, the prestress applying precision is high, automatic optimization of process parameters is achieved through an intelligent PLC system, the product percent of pass is greatly increased, and the production cost is reduced. And the energy consumption and the rejection rate are greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of steel wire preparation, and in particular to a preparation device for high-strength prestressed steel wire and a use method thereof. Background Art

[0002] Modern construction and bridge engineering have increasingly higher requirements for material properties. With the rapid development of large-span bridges, super-high-rise buildings and special structures, traditional steel can hardly meet the requirements in terms of strength, fatigue resistance and stress relaxation resistance. This has prompted the innovation of special preparation equipment with cold drawing, stabilization heat treatment, tension control and anti-corrosion coating technology as the core. This type of equipment uses key modules such as precision temperature-controlled heat treatment furnaces, multi-pass cold drawing deformation systems, stress detection and automatic adjustment units to achieve grain refinement, dislocation density improvement and residual stress optimization of steel wire, ultimately achieving tensile strength and low relaxation characteristics above 1570MPa.

[0003] The traditional prestressed steel wire production process has significant deficiencies in strength, precision, durability and production efficiency, resulting in the prestressed steel wire produced having low strength, short life and high energy consumption.

[0004] Therefore, in view of the fact that the above-mentioned traditional prestressed steel wire production process has significant deficiencies in strength, precision, durability and production efficiency, which leads to the problems of low strength, short life and high energy consumption of the prestressed steel wire produced, a high-strength prestressed steel wire preparation device and its use method can be designed. Summary of the Invention

[0005] In order to overcome the significant deficiencies in the traditional prestressed steel wire production process in terms of strength, precision, durability and production efficiency, which lead to the problems of low strength, short life and high energy consumption of the prestressed steel wire produced.

[0006] The technical solution of the present invention is: a preparation device for high-strength prestressed steel wire, comprising a pay-off mechanism, a pretreatment unit, a drawing mechanism, a heat treatment furnace, a cooling device, a stress applying mechanism, an online stress detector and a take-up mechanism; The stress applying mechanism includes a tension roller group driven by a servo motor, a hydraulic damper and an online stress detector. The roller surface of the tension roller group is provided with a V-shaped groove with an angle of 90°±5°; Preferably, the online stress detector monitors the strain of the steel wire in real time through an optical fiber strain sensor, and is linked with a PLC control system to dynamically adjust the tension to within an error range of ±1% of the set value.

[0007] Preferably, the pretreatment unit includes a pickling tank, an ultrasonic cleaning machine and a phosphating treatment tank. The pickling tank contains a hydrochloric acid solution with a concentration of 15% to 20%, the temperature is maintained at 40°C to 50°C, the treatment time is 5 to 8 minutes, the frequency of the ultrasonic cleaning machine is 28kHz to 40kHz, the power density is ≥5W / cm², the cleaning time is 3 to 5 minutes, and the phosphating treatment tank uses a zinc-based phosphating solution with a total acidity of 18 to 25 points and a free acidity of 2.5 to 4.5 points to form a phosphating film of 3 to 8 μm.

[0008] Preferably, the drawing mechanism includes a drawing die and a lubricant injection device. The drawing die has a die entrance angle of 12°~16°, a ratio of the sizing strip length to the wire diameter of 1.2:1~1.5:1, an injection pressure of the lubricant injection device of 0.3~0.5MPa, and the lubricant is a nanographite suspension with a particle size of ≤200nm and a concentration of 8%~12%. A diameter laser measuring instrument is provided after each stage of drawing with a measurement accuracy of ±0.01mm. The data is fed back to the PLC control system to adjust the drawing speed of the next stage.

[0009] Preferably, the heat treatment furnace is a segmented induction heating furnace, including an austenitizing zone and a tempering zone. The temperature of the austenitizing zone is 850°C~900°C, the heating rate is 50°C / s~80°C / s, nitrogen protection is introduced, the oxygen content is ≤50ppm, the temperature of the tempering zone is 450°C~500°C, and the holding time is 30~60s.

[0010] Preferably, the cooling device includes an air cooling section and a water mist cooling section. The wind speed of the air cooling section is 8~12m / s, the wind temperature is 20℃~30℃, the cooling time is 10~15s, the water droplet size of the water mist cooling section is 50~100μm, the water pressure is 0.1~0.3MPa, the atomization angle is 60°~90°, and the cooling rate is controlled at 50℃ / s~100℃ / s.

[0011] Preferably, the PLC control system integrates the following functional modules: The tension closed-loop control module adjusts the servo motor torque output according to the feedback signal from the stress detector, with a response time of ≤0.1s; Process database, storing the drawing speed, heat treatment temperature and tension parameter combinations for different steel wire specifications; The fault warning module monitors equipment vibration, temperature and lubricant flow in real time, and triggers audible and visual alarms when an abnormality occurs.

[0012] Preferably, the method for using the device for preparing high-strength prestressed steel wire comprises the following steps: S1, first the coiled wire is automatically unwound by the pay-off mechanism and initially straightened by the straightening roller to ensure its straightness before entering the subsequent process. Then, the wire is placed in the pre-treatment unit; S2, soak the steel wire in a pickling tank for 5-8 minutes to completely remove the oxide scale on the steel wire surface, then use an ultrasonic cleaner with high-frequency vibration combined with deionized water to rinse the steel wire to remove the residual acid and particles. Finally, use a phosphating treatment tank to form a 3-8μm zinc phosphating film on the steel wire surface to enhance the subsequent drawing lubricity of the steel wire; In step S3, the pretreated steel wire enters the drawing mechanism and is cold-drawn using a four-stage progressive drawing die. The compression rate of each die is controlled at 15% to 20%, and the total compression rate is ≥50%. The diameter of the steel wire is ultimately reduced to 3.0 to 4.5 mm. During the drawing process, a lubricant sprayer continuously sprays a nanographite suspension onto the die and the steel wire surface. After each stage of drawing, a laser measuring instrument detects the steel wire diameter in real time, and the data is fed back to the PLC control system, which dynamically adjusts the drawing speed. S4, the drawn steel wire enters a segmented induction heating furnace for heat treatment. The austenitizing zone heats the steel wire to 850-900°C at a rate of 50-80°C / s and is protected by nitrogen. Subsequently, the steel wire enters the tempering zone and is kept at 450-500°C for 30-60 seconds. S5, the heat-treated steel wire enters the cooling device, first passing through the air cooling section at a wind speed of 8-12m / s to rapidly cool the steel wire from high temperature to 550℃~600℃, then entering the water mist cooling section, where fine water mist of 50-100μm is used to further cool the steel wire to room temperature at a rate of 50℃ / s~100℃ / s; S6, the cooled steel wire enters the stress application mechanism, and a dynamic prestress of 600~800MPa is applied by the tension roller group driven by the servo motor; S7, the steel wire is finally wound by the take-up mechanism.

[0013] Preferably, in step S4, the austenitizing is performed by two-stage heating: in the first stage, heating is performed at a rate of 20°C / s to 30°C / s to 650°C to 700°C, and keeping warm for 10 to 15 seconds; in the second stage, heating is performed at a rate of 50°C / s to 80°C / s to 850°C to 900°C, and keeping warm for 5 to 8 seconds.

[0014] Preferably, in step S6, when dynamic tension is applied, the initial tension is 70% to 75% of the yield strength of the steel wire, and increases by 5 MPa every 5 seconds until the target value is reached; the tension fluctuation is controlled by an online stress detector, and automatic compensation is performed when the deviation exceeds ±2%.

[0015] Beneficial effects of the present invention: 1. Through the coordinated work of dynamic prestress control and multi-stage heat treatment process, the tensile strength of the steel wire is stably increased to over 1570MPa, thereby significantly improving the durability and fatigue resistance of the steel wire.

[0016] 2. The closed-loop controlled tension system and online detection technology are used, with high precision in prestressing. The intelligent PLC system is used to automatically optimize process parameters, which greatly improves the product qualification rate and significantly reduces energy consumption and scrap rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Shown is a schematic diagram of the device framework of the present invention; Figure 2 What is shown is a schematic diagram of the workflow of the present invention. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0019] See also Figure 1 , the present invention provides an embodiment: a high-strength prestressed steel wire preparation device, comprising a wire-paying mechanism, a pretreatment unit, a drawing mechanism, a heat treatment furnace, a cooling device, a stress applying mechanism, an online stress detector, a coating unit and a wire-taking mechanism; The stress applying mechanism includes a tension roller group driven by a servo motor, a hydraulic damper and an online stress detector. The roller surface of the tension roller group is provided with a V-shaped groove with an angle of 90°±5° to enhance the positioning stability of the steel wire; The online stress detector monitors the steel wire strain in real time through an optical fiber strain sensor and is linked with a PLC control system to dynamically adjust the tension to within an error range of ±1% of the set value.

[0020] The pretreatment unit includes a pickling tank, an ultrasonic cleaning machine and a phosphating treatment tank. The pickling tank contains a hydrochloric acid solution with a concentration of 15% to 20%, the temperature is maintained at 40°C to 50°C, and the treatment time is 5 to 8 minutes. The frequency of the ultrasonic cleaning machine is 28kHz to 40kHz, the power density is ≥5W / cm², and the cleaning time is 3 to 5 minutes. The phosphating treatment tank uses a zinc-based phosphating solution with a total acidity of 18 to 25 points and a free acidity of 2.5 to 4.5 points, forming a phosphating film of 3 to 8 μm.

[0021] The drawing mechanism includes a drawing die and a lubricant injection device. The drawing die has an inlet angle of 12° to 16°, a ratio of the sizing strip length to the wire diameter of 1.2:1 to 1.5:1, an injection pressure of the lubricant injection device of 0.3 to 0.5 MPa, and the lubricant is a nanographite suspension with a particle size of ≤200 nm and a concentration of 8% to 12%. A diameter laser measuring instrument is provided after each stage of drawing with a measurement accuracy of ±0.01 mm. The data is fed back to a PLC control system to adjust the drawing speed of the next stage.

[0022] The heat treatment furnace is a segmented induction heating furnace, including an austenitizing zone and a tempering zone. The temperature of the austenitizing zone is 850°C~900°C, the heating rate is 50°C / s~80°C / s, nitrogen protection is introduced, the oxygen content is ≤50ppm, the temperature of the tempering zone is 450°C~500°C, and the holding time is 30~60s.

[0023] The cooling device includes an air cooling section and a water mist cooling section. The wind speed of the air cooling section is 8~12m / s, the wind temperature is 20℃~30℃, and the cooling time is 10~15s. The water droplet size of the water mist cooling section is 50~100μm, the water pressure is 0.1~0.3MPa, the atomization angle is 60°~90°, and the cooling rate is controlled at 50℃ / s~100℃ / s.

[0024] The PLC control system integrates the following functional modules: The tension closed-loop control module adjusts the servo motor torque output according to the feedback signal from the stress detector, with a response time of ≤0.1s; Process database, storing the drawing speed, heat treatment temperature and tension parameter combinations for different steel wire specifications; The fault warning module monitors equipment vibration, temperature and lubricant flow in real time, and triggers audible and visual alarms when an abnormality occurs.

[0025] For further information, see Figure 2 The method for using the high-strength prestressed steel wire preparation device is described in detail, including the following steps: S1, the coiled steel wire is first automatically unwound by the wire-paying mechanism and preliminarily straightened by the straightening roller to ensure its straightness for subsequent processes. Subsequently, the steel wire enters the pretreatment unit and undergoes pickling, ultrasonic cleaning and phosphating treatment in sequence. The pickling tank uses a 15% to 20% hydrochloric acid solution and soaks the steel wire at a temperature of 40°C to 50°C for 5 to 8 minutes to completely remove the oxide scale on the steel wire surface. Then, an ultrasonic cleaner with high-frequency vibration of 28kHz to 40kHz combined with deionized water is used to rinse the steel wire to remove residual acid and particles. Finally, a phosphating treatment tank is used to form a 3 to 8μm zinc phosphate film on the steel wire surface to enhance the subsequent drawing lubricity of the steel wire.

[0026] S2, the pretreated steel wire enters the drawing mechanism and is cold drawn using a four-stage progressive drawing die. The compression rate of each stage of the die is controlled at 15%~20%, and the total compression rate is ≥50%. Finally, the diameter of the steel wire is reduced to 3.0~4.5mm. During the drawing process, the lubricant injection device continuously sprays nano-graphite suspension (concentration 8%~12%) onto the die and the steel wire surface, thereby reducing friction resistance and preventing the surface from being scratched during steel wire drawing. After each stage of drawing, the laser measuring instrument detects the steel wire diameter in real time, and the data is fed back to the PLC control system, thereby dynamically adjusting the drawing speed to ensure dimensional accuracy (±0.01mm), so that the grain of the steel wire after drawing is refined, the tensile strength is significantly improved, and good plasticity is maintained.

[0027] S3, the drawn steel wire enters a segmented induction heating furnace for heat treatment. The austenitizing zone heats the steel wire to 850℃~900℃ at a rate of 50℃ / s~80℃ / s, and nitrogen protection (oxygen content ≤50ppm) is introduced to prevent surface oxidation of the drawn steel wire. Subsequently, the steel wire enters the tempering zone and is kept at 450℃~500℃ for 30~60s. This step can form a uniform sorbite structure inside the steel wire, so that the hardness of the steel wire is controlled at HRC45~50, and it has the advantages of high strength and toughness. After heat treatment, the tensile strength of the steel wire is ≥1860MPa and the elongation is ≥4%.

[0028] S4, the heat-treated steel wire enters the cooling device and adopts a graded cooling method of air cooling + water mist cooling. The air cooling section quickly cools the steel wire from high temperature to 550℃~600℃ at a wind speed of 8~12m / s to prevent excessive grain growth. Then it enters the water mist cooling section and is further cooled to room temperature at a rate of 50℃ / s~100℃ / s by fine water mist of 50~100μm, thereby reducing the internal stress of the steel wire and avoiding embrittlement of the steel wire.

[0029] In step S5, the cooled steel wire enters the stressing mechanism, where a servo motor-driven tension roller assembly applies a dynamic prestress of 600-800 MPa. The initial tension is set at 70-75% of the wire's yield strength and increases by 5 MPa every 5 seconds until the target value is reached. An online stress detector monitors the wire strain in real time using a fiber optic strain sensor. This data is fed back to the PLC control system, which dynamically adjusts the tension to ensure a fluctuation range of ≤±1%. A hydraulic damper absorbs mechanical vibrations and ensures tension stability. The prestressing time is ≥30 seconds, allowing the wire's internal dislocation structure to fully restructure, significantly improving its relaxation resistance and fatigue life.

[0030] S6, finally, the steel wire is wound by the take-up mechanism.

[0031] Through the above steps, dynamic prestress control and multi-stage heat treatment process work together to make the tensile strength of the steel wire stably reach above 1570MPa, and the elongation ≥4%, thereby significantly improving the durability and fatigue resistance of the steel wire. In addition, the closed-loop control tension system and online detection technology are adopted, and the prestressing accuracy can reach ±1%. The process parameters are automatically optimized through the intelligent PLC system, which greatly improves the product qualification rate and significantly reduces energy consumption and scrap rate. In order to solve the significant deficiencies in the traditional prestressed steel wire production process in terms of strength, precision, durability and production efficiency, resulting in low strength, short life and high energy consumption of the produced prestressed steel wire.

Claims

1. A device for preparing high-strength prestressed steel wire, characterized by: It includes a wire-paying mechanism, a pretreatment unit, a drawing mechanism, a heat treatment furnace, a cooling device, a stress applying mechanism, an online stress detector and a wire-taking mechanism; The stress applying mechanism includes a tension roller group driven by a servo motor, a hydraulic damper and an online stress detector. The roller surface of the tension roller group is provided with a V-shaped groove with an angle of 90°±5°.

2. The device for preparing high-strength prestressed steel wire according to claim 1, characterized in that: The online stress detector monitors the steel wire strain in real time through an optical fiber strain sensor and is linked with a PLC control system to dynamically adjust the tension to within an error range of ±1% of the set value.

3. The device for preparing high-strength prestressed steel wire according to claim 1, characterized in that: The pretreatment unit includes a pickling tank, an ultrasonic cleaning machine and a phosphating treatment tank. The pickling tank contains a hydrochloric acid solution with a concentration of 15% to 20%, the temperature is maintained at 40°C to 50°C, and the treatment time is 5 to 8 minutes. The frequency of the ultrasonic cleaning machine is 28kHz to 40kHz, the power density is ≥5W / cm², and the cleaning time is 3 to 5 minutes. The phosphating treatment tank uses a zinc-based phosphating solution with a total acidity of 18 to 25 points and a free acidity of 2.5 to 4.5 points, forming a phosphating film of 3 to 8 μm.

4. The device for preparing high-strength prestressed steel wire according to claim 1, characterized in that: The drawing mechanism includes a drawing die and a lubricant injection device. The drawing die has an inlet angle of 12° to 16°, a ratio of the sizing strip length to the wire diameter of 1.2:1 to 1.5:1, an injection pressure of the lubricant injection device of 0.3 to 0.5 MPa, and the lubricant is a nanographite suspension with a particle size of ≤200 nm and a concentration of 8% to 12%. A diameter laser measuring instrument is provided after each stage of drawing with a measurement accuracy of ±0.01 mm. The data is fed back to a PLC control system to adjust the drawing speed of the next stage.

5. The device for preparing high-strength prestressed steel wire according to claim 1, characterized in that: The heat treatment furnace is a segmented induction heating furnace, including an austenitizing zone and a tempering zone. The temperature of the austenitizing zone is 850°C~900°C, the heating rate is 50°C / s~80°C / s, nitrogen protection is introduced, the oxygen content is ≤50ppm, the temperature of the tempering zone is 450°C~500°C, and the holding time is 30~60s.

6. The device for preparing high-strength prestressed steel wire according to claim 1, characterized in that: The cooling device includes an air cooling section and a water mist cooling section. The wind speed of the air cooling section is 8~12m / s, the wind temperature is 20℃~30℃, and the cooling time is 10~15s. The water droplet size of the water mist cooling section is 50~100μm, the water pressure is 0.1~0.3MPa, the atomization angle is 60°~90°, and the cooling rate is controlled at 50℃ / s~100℃ / s.

7. The device for preparing high-strength prestressed steel wire according to claim 1, characterized in that: The PLC control system integrates the following functional modules: The tension closed-loop control module adjusts the servo motor torque output according to the feedback signal from the stress detector, with a response time of ≤0.1s; Process database, storing the drawing speed, heat treatment temperature and tension parameter combinations for different steel wire specifications; The fault warning module monitors equipment vibration, temperature and lubricant flow in real time, and triggers audible and visual alarms when an abnormality occurs.

8. A method for using a high-strength prestressed steel wire manufacturing device, comprising: The following steps are included: S1, first the coiled wire is automatically unwound by the pay-off mechanism and initially straightened by the straightening roller to ensure its straightness before entering the subsequent process. Then, the wire is placed in the pre-treatment unit; S2, soak the steel wire in a pickling tank for 5-8 minutes to completely remove the oxide scale on the steel wire surface, then use an ultrasonic cleaner with high-frequency vibration combined with deionized water to rinse the steel wire to remove the residual acid and particles. Finally, use a phosphating treatment tank to form a 3-8μm zinc phosphating film on the steel wire surface to enhance the subsequent drawing lubricity of the steel wire; In step S3, the pretreated steel wire enters the drawing mechanism and is cold-drawn using a four-stage progressive drawing die. The compression rate of each die is controlled at 15% to 20%, and the total compression rate is ≥50%. The diameter of the steel wire is ultimately reduced to 3.0 to 4.5 mm. During the drawing process, a lubricant sprayer continuously sprays a nanographite suspension onto the die and the steel wire surface. After each stage of drawing, a laser measuring instrument detects the steel wire diameter in real time, and the data is fed back to the PLC control system, which dynamically adjusts the drawing speed. S4, the drawn steel wire enters a segmented induction heating furnace for heat treatment. The austenitizing zone heats the steel wire to 850-900°C at a rate of 50-80°C / s and is protected by nitrogen. Subsequently, the steel wire enters the tempering zone and is kept at 450-500°C for 30-60 seconds. S5, the heat-treated steel wire enters the cooling device, first passing through the air cooling section at a wind speed of 8-12m / s to rapidly cool the steel wire from high temperature to 550℃~600℃, then entering the water mist cooling section, where fine water mist of 50-100μm is used to further cool the steel wire to room temperature at a rate of 50℃ / s~100℃ / s; S6, the cooled steel wire enters the stress application mechanism, and a dynamic prestress of 600~800MPa is applied by the tension roller group driven by the servo motor; S7, the steel wire is finally wound by the take-up mechanism.

9. The method for using the device for preparing high-strength prestressed steel wire according to claim 1, characterized in that: In step S4, the austenitization is carried out by two-stage heating: in the first stage, the temperature is heated to 650°C~700°C at a rate of 20°C / s~30°C / s, and the temperature is kept for 10~15s; in the second stage, the temperature is heated to 850°C~900°C at a rate of 50°C / s~80°C / s, and the temperature is kept for 5~8s.

10. The method for using the device for preparing high-strength prestressed steel wire according to claim 1, characterized in that: In step S6, when dynamic tension is applied, the initial tension is 70% to 75% of the yield strength of the steel wire, and increases by 5 MPa every 5 seconds until the target value is reached; the tension fluctuation is controlled by an online stress detector, and automatic compensation is performed when the deviation exceeds ±2%.

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