Device and method for improving yield strength and hardness of wheel hub of rail transit vehicle

Abstract

The invention belongs to the technical field of rail transit vehicles, and particularly relates to a method for improving yield strength and hardness of a wheel hub of a rail transit vehicle. The spray pipe (4) moves downwards to enter a hub hole (6) of a wheel hub (5); the chain plate machine (2) drives the wheel (1) to horizontally move, the nozzle (7) sprays cooling mist, and the nozzle control system (3) controls the nozzle (7) to synchronously and horizontally move along with the wheel (1); the front nozzle control system (3) drives the control nozzle (7) to synchronously and horizontally move to the rear position from the front position when horizontally moving along with the wheel (1), and then the spray pipe (4) of the next nozzle control system (3) moves downwards to enter the hub hole (6) of the wheel hub (5). According to the method, controlled cooling of segmented air injection is conducted on the hub hole according to the rhythm of the wheel, the cooling rate of all parts of the hub is guaranteed, and therefore the yield strength and hardness of the hub are effectively improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of rail transit vehicles, more particularly, to a method for improving the yield strength and hardness of a rail transit vehicle wheel hub. BACKGROUND

[0002] The service safety and stability of locomotive wheels, as key components of high-power freight locomotives, are particularly important. During the maintenance process in each locomotive depot, it is found that the inner hole of the high-power locomotive wheel hub is expanded, and the hole size is out of tolerance, which leads to the fact that the wheel set cannot be disassembled and reassembled, resulting in the scrap of the wheel and increasing the maintenance cost. During the wheel set assembly process, the wheel hub hole and the axle wheel seat are in interference fit, and there is a difference in strength and hardness between the two, which will cause different deformations. The higher the strength and hardness, the smaller the deformation. The problem of hole size expansion of the wheel hub hole during disassembly indicates that the yield strength and hardness of the wheel hub hole are insufficient. Therefore, appropriately improving the yield strength and hardness of the wheel hub hole is the key to solving the problem of hole size expansion.

[0003] The wheel, as a whole workpiece, is composed of a rim, a web plate and a hub. The requirements of various standards and technical conditions are all for the rim and web plate parts, and there is no clear specification for the process and performance of the hub part. During the heat treatment process of the wheel, the heat treatment state of the hub is normalizing + tempering. As long as the composition and heat treatment process are determined, the strength and hardness of the wheel hub part will be determined. At present, the material of the high-power locomotive wheel on the domestic large railway is mainly J2 and J11, and it is bound to the vehicle type, and the wheel material cannot be replaced, the composition adjustment space is limited, so it is necessary to cool the hub part by a specific heat treatment device or method. However, the strength and hardness of the hub are too high, which will cause greater deformation of the axle wheel seat during wheel set assembly, and increase the axle wheel seat scratch. In the prior art, a technology named "a spoke wheel and rail transit vehicle" and a publication (announcement) number "CN116852909B" is disclosed, which relates to the field of vehicle engineering technology. The spoke wheel includes a rim, a hub and a plurality of spokes; the hub is located in the middle of the rim in the radial direction; all the spokes form a spoke assembly, the radial inner end of each spoke is fixed to the outer circumferential surface of the hub and the radial outer end is fixed to the inner circumferential surface of the rim; on the inner circumferential surface of the rim, the connection area of the spoke assembly is located in the middle in the axial direction, and the portions on both sides of the connection area in the axial direction are respectively provided with annular mounting grooves, and a noise reduction damping ring is mounted in the mounting groove. Since the mounting space of the noise reduction damping ring is left on both sides of the connection area of the spoke assembly in the rim in the axial direction, the noise reduction damping ring can be installed to reduce noise, which can improve the noise reduction capability of the spoke wheel.

[0004] However, the technology does not involve the technical problems and technical solutions of the present application. SUMMARY

[0005] The technical problem to be solved by the present application is: in view of the deficiencies of the prior art, to provide a method for improving the yield strength and hardness of the wheel hub of the rail transit vehicle, which is simple in steps, does not affect the performance of the wheel rim and the web, follows the rhythm of the wheel, controls the cooling of the wheel hub hole by segmental gas injection, ensures the cooling rate of each part of the wheel hub, and effectively improves the yield strength and hardness of the wheel hub.

[0006] To solve the above technical problems, the technical solution adopted by the present application is: The present application is a method for improving the yield strength and hardness of the wheel hub of the rail transit vehicle, and the steps of the method are: S1. Place the quenched wheel on the chain plate machine to transport it to the tempering furnace; S2. The nozzle control system is arranged above the chain plate machine, when the wheel starts to move, the spray pipe of the nozzle control system moves downward into the wheel hub hole of the wheel hub; the nozzle at the lower end of the spray pipe is a fan-shaped nozzle, the nozzle is located at the middle line position of the wheel hub hole, the chain plate machine drives the wheel to move horizontally, the nozzle control system drives the nozzle to rotate 360°, and sprays cooling mist, the nozzle control system controls the nozzle to move horizontally synchronously with the wheel; S3. A plurality of nozzle control systems are arranged above the chain plate machine, when the control nozzle of the previous nozzle control system moves horizontally from the front position to the rear position synchronously with the wheel, the spray pipe of the previous nozzle control system moves upward out of the wheel hub hole of the wheel hub; the spray pipe of the next nozzle control system moves downward into the wheel hub hole of the wheel hub; S4. The wheel hub hole of the wheel is sent into the tempering furnace after being cooled by the cooling mist of the nozzle.

[0007] The total time of the wheel in the chain plate machine before entering the tempering furnace is not less than 30 min; the total air cooling time of the wheel hub is not less than 20 min.

[0008] The nozzle is a fan-shaped nozzle with a spray angle of 100°-110°, a gas pressure of 0.2-0.3 MPa, and a flow rate of 5 Nm3 / h-7 Nm3 / h.

[0009] The rotation speed of the nozzle is 20-30 rpm.

[0010] The nozzle is a fan-shaped nozzle with a larger middle injection pressure than the injection pressure on both sides.

[0011] The driving gear of the nozzle control system, the driven gear, the driving motor drive the driving chain to rotate, the driving chain rotation drives the nozzle to move linearly along the horizontal direction.

[0012] The rotary motor of the nozzle control system, the telescopic cylinder drive the nozzle to rotate and drive the nozzle to stretch and retract.

[0013] The nozzle control system comprises three, three nozzle control systems are arranged from the direction close to the quenching furnace to the direction close to the tempering furnace, and each nozzle control system is arranged horizontally.

[0014] The present application also relates to a device for improving the yield strength and hardness of a wheel hub of a rail transit vehicle, comprising a chain conveyor and a nozzle control system, wherein the nozzle control system comprises a driving gear and a driven gear, the driving gear is fixedly connected with a driving motor, the driving motor and the driven gear are connected to a system frame, a driving chain is sleeved on the driving gear and the driven gear, a rotary motor is fixedly installed outside the driving chain, a telescopic cylinder is fixedly connected with a rotating shaft of the rotary motor, the telescopic cylinder is fixedly connected with an upper end of a nozzle pipe, a lower end of the nozzle pipe is fixedly connected with a nozzle, and the nozzle pipe is vertically arranged.

[0015] The chain conveyor 2 comprises a driving roller, a driven roller, a plurality of bearing rollers, a chain plate, a driving roller driving motor 19, a driving roller driving motor, a driven roller and bearing rollers which are installed on a chain conveyor frame, the chain plate is sleeved on the driving roller and the driven roller, the plurality of bearing rollers are supported on the lower part of the upper layer of the chain plate, the driving roller is connected with the driving roller driving motor, and the chain conveyor extends from a position close to a quenching furnace to a position close to a tempering furnace.

[0016] The technical scheme of the present application has the following working principles and beneficial effects: The method for improving the yield strength and hardness of the wheel hub of the rail transit vehicle wheel comprises the following steps: setting a chain plate machine and a nozzle control system, the chain plate machine is used for conveying the wheel after quenching in a quenching furnace to a tempering furnace for tempering, and the nozzle control system is used for separately cooling the inside of the wheel hub hole of the wheel hub, thereby solving the problem of poor heat dissipation condition of the wheel hub, improving the yield strength and hardness of the wheel hub. Specifically, the chain plate machine comprises a driving roller, a driven roller, a plurality of bearing rollers, a chain plate, and a driving roller driving motor, the chain plate is sleeved on the driving roller and the driven roller, the plurality of bearing rollers are supported on the lower part of the upper layer of the chain plate, the driving roller is connected with the driving roller driving motor, when the driving roller driving motor drives the driving roller to rotate, the chain plate is driven to rotate, and when the chain plate rotates, the wheel that has been taken out of the quenching furnace can be driven to move towards the tempering furnace. During the movement of the wheel towards the tempering furnace, because the wheel moves for a period of time, therefore, a plurality of nozzle control systems are arranged above the chain plate machine, each nozzle control system covers a distance of the chain plate, when the wheel starts to move, the spray pipe of the nozzle control system moves downwards into the wheel hub hole of the wheel hub; the nozzle at the lower end of the spray pipe is a fan-shaped nozzle, the nozzle is located at the middle line position of the wheel hub hole, the driving chain is sleeved on the driving gear and the driven gear of the nozzle control system, when the driving chain rotates, the spray pipe moves horizontally and synchronously with the wheel, when the rotary motor rotates, the telescopic cylinder rotates, the spray pipe rotates driven by the telescopic cylinder, and the nozzle rotates driven by the spray pipe. The chain plate machine drives the wheel to move horizontally, the nozzle control system drives the nozzle to rotate by 360 degrees, and the nozzle sprays cooling mist, the cooling mist acts on the inner wall of the wheel hub hole, and the inner wall of the wheel hub hole is cooled. The nozzle control system controls the nozzle to move horizontally synchronously with the wheel. When the previous nozzle control system drives the control nozzle to move horizontally from the front position to the rear position synchronously with the wheel, the spray pipe of the previous nozzle control system moves upwards and leaves the wheel hub hole of the wheel hub; the spray pipe of the next nozzle control system moves downwards into the wheel hub hole of the wheel hub. In this way, the atomized cooling water sprayed by the nozzle acts on the inner wall of the wheel hub hole, and the inner wall of the wheel hub hole is cooled. BRIEF DESCRIPTION OF DRAWINGS

[0017] The content expressed by each figure of the present specification and the marks in the figures are briefly described as follows: Figure 1 The structural arrangement diagram of the device for improving the yield strength and hardness of the wheel hub of the rail transit vehicle wheel; Figure 2 The nozzle flow distribution diagram of the device for improving the yield strength and hardness of the wheel hub of the rail transit vehicle wheel; Figure 3 The gas cooling coverage area diagram of the device for improving the yield strength and hardness of the wheel hub of the rail transit vehicle wheel; Figure 4 The wheel rim yield strength inspection position diagram; Figure 5 This is a schematic diagram for testing the hardness of a wheel rim along the axial direction. Figure 6 Example 1 and Comparative Example 1 are based on... Figure 4 Results of room temperature tensile properties from sampling and testing; Figure 7 Example 1 and Comparative Example 1 are based on... Figure 5 The hardness distribution at the inspection location was examined. Figure 8 Example 2 and Comparative Example 2 are based on Figure 4 Results of room temperature tensile properties from sampling and testing; Figure 9 Example 2 and Comparative Example 2 are based on Figure 5 The hardness distribution at the inspection location was examined. Figure 10 Table of main chemical composition of wheel steel for examples and comparative examples.

[0018] The labels in the attached diagram are as follows: 1. Wheel; 2. Chain conveyor; 3. Nozzle control system; 4. Spray pipe; 5. Wheel hub; 6. Hub hole; 7. Nozzle; 8. Center line; 9. Drive gear; 10. Driven gear; 11. Drive motor; 12. Drive chain; 13. Rotary motor; 14. Telescopic cylinder; 15. Drive roller; 16. Driven roller; 17. Carrying roller; 18. Chain plate; 19. Drive roller drive motor. Detailed Implementation

[0019] The following description, with reference to the accompanying drawings, provides a more detailed explanation of the specific embodiments of the present invention, including the shape and structure of each component, the relative positions and connections between the parts, the functions and working principles of each part: As attached Figure 1 -Appendix Figure 10 As shown, this invention relates to a method for improving the yield strength and hardness of a rail transit vehicle wheel hub. The steps of this method are as follows: S1. The quenched wheel 1 is placed on the chain conveyor 2 and conveyed to the tempering furnace. S2. The nozzle control system 3 is set above the chain conveyor 2. When the wheel 1 starts to move, the nozzle pipe 4 of the nozzle control system 3 moves downward and enters the hub hole 6 of the wheel hub 5. The nozzle 7 at the lower end of the nozzle pipe 4 is a fan-shaped nozzle. The nozzle 7 is located at the middle line 8 of the hub hole 6. The chain conveyor 2 drives the wheel 1 to move horizontally. The nozzle control system 3 drives the nozzle 3 to rotate 360° and sprays out cooling mist. The nozzle control system 3 controls the nozzle 7 to move horizontally synchronously with the wheel 1. S3. Multiple nozzle control systems 3 are set above the chain conveyor 2. When the previous nozzle control system 3 drives the nozzle 7 to move horizontally from the front position to the rear position synchronously with the wheel 1, the nozzle pipe 4 of the previous nozzle control system 3 moves upward and leaves the hub hole 6 of the wheel hub 5. The nozzle pipe 4 of the next nozzle control system 3 moves downward and enters the hub hole 6 of the wheel hub 5. S4. The hub hole 6 of the wheel 1 is cooled by the cooling mist from the nozzle and then sent to the tempering furnace. The above steps address the shortcomings of existing technologies and propose an improved technical solution. In the structural setup, a chain conveyor 2 and a nozzle control system 3 are included. The chain conveyor 2 is used to transport the wheels quenched in the quenching furnace to the tempering furnace for tempering. The nozzle control system 3 is used to individually cool the inside of the wheel hub bore, solving the problem of poor heat dissipation in the wheel hub and improving the yield strength and hardness of the wheel hub. Specifically, the chain conveyor 2 includes a drive roller 15, a driven roller 16, multiple support rollers 17, a chain plate 18, and a drive roller drive motor 19. The chain plate 18 is mounted on the drive roller 15 and the driven roller 16. The multiple support rollers 17 are supported on the upper and lower parts of the chain plate 18. The drive roller 15 is connected to the drive roller drive motor 19. When the drive roller drive motor drives the drive roller to rotate, it drives the chain plate to rotate. When the chain plate 18 rotates, it can move the wheels that have exited the quenching furnace towards the tempering furnace. During the movement of the wheel towards the tempering furnace, because the wheel movement will continue for a period of time, multiple nozzle control systems 3 are installed above the chain conveyor 2. Each nozzle control system 3 covers a certain distance of the chain plate. When the wheel 1 begins to move, the nozzle pipe 4 of the nozzle control system 3 moves downward and enters the hub hole 6 of the wheel hub 5. The nozzle 7 at the lower end of the nozzle pipe 4 is a fan-shaped nozzle, located at the center line 8 of the hub hole 6. The drive gear 9 and driven gear 10 of the nozzle control system 3 are fitted with a drive chain 12. When the drive chain rotates, it drives the nozzle to move horizontally and synchronously with the wheel 1. When the rotary motor rotates, it drives the telescopic cylinder to rotate, which in turn drives the nozzle 4 to rotate the nozzle 7. The chain conveyor 2 drives the wheel 1 to move horizontally, and the nozzle control system 3 drives the nozzle 3 to rotate 360° and spray cooling mist. The cooling mist acts on the inner wall of the hub hole to cool the inner wall of the hub hole. The nozzle control system 3 controls the nozzle 7 to move horizontally synchronously with the wheel 1.As the wheel 1 moves horizontally, the preceding nozzle control system 3 drives the control nozzle 7 to move synchronously from the front position to the rear position. Then, the nozzle 4 of the preceding nozzle control system 3 moves upwards, leaving the hub hole 6 of the wheel hub 5; the nozzle 4 of the next nozzle control system 3 moves downwards, entering the hub hole 6 of the wheel hub 5. In this way, the atomized cooling water sprayed by the nozzle 7 acts on the inner wall of the hub hole, achieving cooling of the inner wall. The method for improving the yield strength and hardness of rail transit vehicle wheel hubs described in this invention is simple in procedure. Without affecting the performance of the wheel rim and spokes, it follows the rhythm of the wheel to perform segmented air jet cooling of the hub hole, ensuring the cooling rate of each part of the hub, thereby effectively improving the yield strength and hardness of the hub.

[0020] Before step S1, two new steps are performed: heating and heat preservation of various parts of the wheel; taking the heated and heat-preserved wheel out of the furnace and air-cooling the wheel hub during the rim quenching and cooling process; and placing the air-cooled wheel on a chain conveyor (a conveying device for the wheel before it enters the tempering furnace) for transportation, during which the cooling process of the rim hole is completed.

[0021] The total conveying time of the wheels on the chain conveyor 2 before entering the tempering furnace shall not be less than 30 minutes; the total air cooling time of the wheel hub 5 shall not be less than 20 minutes. In the above structure, the wheels are continuously conveyed on the chain conveyor 2 for a period of time, while the cooling time of the wheel hub is less than the total conveying time of the wheels on the chain conveyor 2 before entering the tempering furnace, and the cooling time of the wheel hub shall also be greater than 20 minutes.

[0022] The nozzle 7 is a fan-shaped nozzle with a spray angle of 100°-110°, an air pressure of 0.2-0.3MPa, and a flow rate of 5Nm3 / h-7Nm3 / h. With this structure, during wheel hub cooling, the pressurized nozzle sprays cooling mist that covers the entire surface of the wheel hub bore.

[0023] The nozzle rotation speed is 20-30 rpm. Nozzle 7 is a fan-shaped nozzle with a higher injection pressure in the center than on both sides. In the above structure, during the wheel heat treatment process, the wheel hub undergoes normalizing followed by tempering. During normalizing, due to the large overall size of the wheel hub and poor heat dissipation conditions within the hub bore, cooling is slow, resulting in coarse pearlite structure with low strength. Furthermore, because the cooling conditions are worst in the center, the hub bore exhibits higher strength on both sides than in the center along the axial direction. This patent uses a fan-shaped nozzle with a strong center and weak sides, combined with an air-cooling + gas-cooling cooling process, to control the overall yield strength and hardness level of the wheel hub.

[0024] The nozzle control system 3, comprising a drive gear 9, a driven gear 10, and a drive motor 11, drives the drive chain 12 to rotate. This rotation of the drive chain 12 causes the nozzle 4 to move linearly in the horizontal direction. This structure enables rotation control of the drive chain. Furthermore, rotating the drive motor 11 in different directions allows the drive chain to move horizontally forward or horizontally backward to reset.

[0025] The rotary motor 13 and telescopic cylinder 14 of the nozzle control system 3 drive the nozzle pipe 4 to rotate, which in turn drives the nozzle 7 to rotate and extend / retract. In this structure, when the nozzle is being cooled, the rotary motor rotates, causing the nozzle to reciprocate and spray cooling mist. When the nozzle needs to enter the rim hole of the wheel, the telescopic component extends; when the nozzle leaves the rim hole, the telescopic component retracts.

[0026] The nozzle control system 3 comprises three nozzle control systems 3 arranged horizontally from the direction closest to the quenching furnace to the direction closest to the tempering furnace. In this structure, when the nozzles spray cooling mist, the pressure is controlled at 0.3 MPa, the nozzle angle at 110°, and the jet flow rate at 6.8 Nm³ / h. The cooling time for the first and third nozzle control systems 3 is no less than 6 minutes, and the cooling time for the second nozzle control system 3 is no less than 7 minutes.

[0027] This invention also relates to a device for improving the yield strength and hardness of a rail transit vehicle wheel hub. This device, with a simple structure, controls cooling of the hub bore through segmented jetting, following the wheel's rhythm, without affecting the performance of the wheel rim and spokes, ensuring the cooling rate of each part of the hub and thus effectively improving the yield strength and hardness of the hub. The device includes a chain conveyor 2 and a nozzle control system 3. The nozzle control system 3 includes a drive gear 9 and a driven gear 10. The drive gear 9 is fixedly connected to a drive motor 11. The drive motor 11 and the driven gear 10 are respectively connected to the system frame. A drive chain 12 is mounted on the drive gear 9 and the driven gear 10. A rotary motor 13 is fixedly installed on the outside of the drive chain 12. The shaft of the rotary motor 13 is fixedly connected to a telescopic cylinder 14. The telescopic cylinder 14 is fixedly connected to the upper end of a nozzle 4. The lower end of the nozzle 4 is fixedly connected to a nozzle 7. The nozzle 4 is arranged vertically. The chain plate machine 2 includes a drive roller 15, a driven roller 16, multiple support rollers 17, a chain plate 18, a drive roller drive motor 19, and the drive roller drive motor 19, driven roller 16, and support roller 17 are respectively mounted on the chain plate machine frame. The chain plate 18 is fitted on the drive roller 15 and the driven roller 16. The multiple support rollers 17 are supported on the upper and lower parts of the chain plate 18. The drive roller 15 is connected to the drive roller drive motor 19. The chain plate machine 2 extends from a position near the quenching furnace to a position near the tempering furnace.

[0028] The present invention will now be described in detail with reference to Examples 1 and 2. Example

[0029] This embodiment uses wheel steel 1 from Table 1 for wheel production. The hot forming of the blank wheel is completed according to the production process of billet cutting → heating → descaling → pre-forming → forming → rolling → punching → slow cooling. Then, the blank wheel is held in a furnace at 880℃ for 3.5 hours before being removed from the furnace. After removal, the hub hole is air-cooled for 640 seconds. After that, it is placed on a chain conveyor for segmented air cooling using a fan-shaped nozzle with a 110° spray angle, a cooling air pressure of 0.3MPa, and a flow rate of 6.8Nm³ / h. Air cooling is performed for 6 minutes in the first and third segments, 7 minutes in the second segment, and 11 minutes for air cooling. The total time on the chain conveyor before entering the tempering furnace is 31 minutes. Then, the wheel is heated to 490℃ and held for tempering treatment for ≥5 hours. After removal from the furnace, the wheel is then processed according to… Figure 4 Tensile specimen sampling and testing shall be carried out in accordance with... Figure 5 Perform a cross-sectional hardness test.

[0030] Comparative Example 1: The wheel steel used in this comparative example is from the same furnace and has the same specifications as that in Example 1. The hot forming of the blank wheel was completed according to the production process of billet cutting → heating → descaling → pre-forming → forming → rolling → punching → slow cooling. Then, the blank wheel was held in a furnace at 880℃ for 3.5 hours before being removed from the furnace. After removal, the wheel hub was air-cooled for 19 minutes, and then tempered at 490℃ for ≥5 hours. Figure 4 Tensile specimen sampling and testing shall be carried out in accordance with... Figure 5 Cross-sectional hardness testing was performed. Tensile and hardness analyses were conducted on Example 1 and Comparative Example 1. Tensile properties were tested according to GB / T228.1 "Metallic materials, tensile testing—Part 1: Test at room temperature," and hardness was measured according to GB / T231.1 "Metallic materials, Brinell hardness testing—Part 1: Test method." The comparison results of yield strength and cross-sectional hardness of the wheel rims are as follows: Figure 6 , Figure 7 As shown, the solution of the present invention can significantly improve the yield strength of the wheel hub, with a particularly noticeable improvement effect on the center section, which is beneficial for improving the consistency of the wheel hub's axial performance. Example

[0031] This embodiment uses wheel steel 2 from Table 1 for wheel production. The hot forming of the blank wheel is completed according to the production process of billet cutting → heating → descaling → pre-forming → forming → rolling → punching → slow cooling. Then, the blank wheel is held in a furnace at 890℃ for 3 hours before being removed from the furnace. After removal, the hub hole is air-cooled for 620 seconds. After that, it is placed on a chain conveyor for segmented air cooling using a fan-shaped nozzle with a spray angle of 110°, a cooling air pressure of 0.3MPa, and a flow rate of 6.8Nm³ / h. Air cooling is performed for 6.5 minutes in the first and third segments, 7.5 minutes in the second segment, and 12 minutes for air cooling. The total time on the chain conveyor before entering the tempering furnace is 32.5 minutes. Then, the wheel is heated and held at 480℃ for tempering treatment for ≥5 hours. After removal from the furnace, the wheel is then processed according to… Figure 4 Tensile specimen sampling and testing shall be carried out in accordance with... Figure 5 Perform a cross-sectional hardness test.

[0032] Comparative Example 2: The wheel steel used in this comparative example is from the same furnace and is of the same specification as in Example 2. The hot forming of the blank wheel was completed according to the production process of billet cutting → heating → descaling → preforming → forming → rolling → punching → slow cooling. Then, the blank wheel was held in a furnace at 890℃ for 3 hours before being removed from the furnace. After removal, the wheel hub was air-cooled for 32 minutes, and then tempered at 480℃ for ≥5 hours. Figure 4 Tensile specimen sampling and testing shall be carried out in accordance with... Figure 5 Perform a cross-sectional hardness test.

[0033] Tensile and hardness analyses were performed on Example 2 and Comparative Example 2. Tensile properties were tested according to GB / T228.1 "Metallic materials, tensile testing—Part 1: Test at room temperature," and hardness was measured according to GB / T231.1 "Metallic materials, Brinell hardness testing—Part 1: Test method." The comparison results of yield strength and cross-sectional hardness of the wheel rims are as follows: Figure 8 , Figure 9 As shown, the solution of the present invention can significantly improve the yield strength of the wheel hub, with a particularly noticeable improvement effect on the center section, which is beneficial for improving the consistency of the wheel hub's axial performance.

[0034] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any improvements made by adopting the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A method for improving the yield strength and hardness of a rail transit vehicle wheel hub, characterized in that: The steps of the method for improving the yield strength and hardness of rail transit vehicle wheel hubs are as follows: S1. Place the quenched wheel (1) on the chain conveyor (2) and transport it to the tempering furnace; S2. The nozzle control system (3) is set above the chain conveyor (2). When the wheel (1) starts to move, the nozzle pipe (4) of the nozzle control system (3) moves downward and enters the hub hole (6) of the wheel hub (5). The nozzle (7) at the lower end of the nozzle pipe (4) is a fan-shaped nozzle. The nozzle (7) is located at the middle line (8) of the hub hole (6). The chain conveyor (2) drives the wheel (1) to move horizontally. The nozzle control system (3) drives the nozzle to rotate 360° and sprays out cooling mist. The nozzle control system (3) controls the nozzle (7) to move horizontally synchronously with the wheel (1). S3. Multiple nozzle control systems (3) are set above the chain conveyor (2). When the previous nozzle control system (3) drives the control nozzle (7) to move horizontally from the front position to the rear position as the wheel (1) moves horizontally, the nozzle (4) of the previous nozzle control system (3) moves upward and leaves the hub hole (6) of the wheel hub (5); the nozzle (4) of the next nozzle control system (3) moves downward and enters the hub hole (6) of the wheel hub (5). S4. The hub hole (6) of the wheel (1) is cooled by the cooling mist from the nozzle and then sent to the tempering furnace.

2. The method for improving the yield strength and hardness of rail transit vehicle wheel hubs according to claim 1, characterized in that: The total time for the wheels to be conveyed on the chain conveyor (2) before entering the tempering furnace shall not be less than 30 minutes; the total time for the wheel hub (5) to be air-cooled shall not be less than 20 minutes.

3. The method for improving the yield strength and hardness of rail transit vehicle wheel hubs according to claim 1 or 2, characterized in that: The nozzle (7) is a fan-shaped nozzle with a spray angle of 100°-110°, an air pressure of 0.2-0.3MPa, and a flow rate of 5Nm3 / h-7Nm3 / h.

4. The method for improving the yield strength and hardness of rail transit vehicle wheel hubs according to claim 1 or 2, characterized in that: The nozzle rotation speed is 20-30 revolutions per minute.

5. The method for improving the yield strength and hardness of rail transit vehicle wheel hubs according to claim 1 or 2, characterized in that: The nozzle (7) is a fan-shaped nozzle with a central spray pressure greater than the two side spray pressures.

6. The method for improving the yield strength and hardness of rail transit vehicle wheel hubs according to claim 1 or 2, characterized in that: The drive gear (9), driven gear (10), and drive motor (11) of the nozzle control system (3) drive the drive chain (12) to rotate, and the rotation of the drive chain (12) causes the nozzle (4) to move linearly in the horizontal direction.

7. The method for improving the yield strength and hardness of rail transit vehicle wheel hubs according to claim 1 or 2, characterized in that: The rotary motor (13) and telescopic cylinder (14) of the nozzle control system (3) drive the nozzle (4) to rotate, which in turn drives the nozzle (7) to rotate and extend.

8. The method for improving the yield strength and hardness of rail transit vehicle wheel hubs according to claim 1 or 2, characterized in that: The nozzle control system (3) includes three nozzle control systems (3) arranged from the direction near the quenching furnace to the direction near the tempering furnace, and each nozzle control system (3) is arranged horizontally.

9. The apparatus for improving the yield strength and hardness of a rail transit vehicle wheel hub according to any one of claims 1 to 8, characterized in that: The system includes a chain conveyor (2) and a nozzle control system (3). The nozzle control system (3) includes a drive gear (9) and a driven gear (10). The drive gear (9) is fixedly connected to a drive motor (11). The drive motor (11) and the driven gear (10) are respectively connected to the system frame. A drive chain (12) is mounted on the drive gear (9) and the driven gear (10). A rotary motor (13) is fixedly installed on the outside of the drive chain (12). The rotating shaft of the rotary motor (13) is fixedly connected to a telescopic cylinder (14). The telescopic cylinder (14) is fixedly connected to the upper end of the nozzle (4). The lower end of the nozzle (4) is fixedly connected to a nozzle (7). The nozzle (4) is arranged vertically.

10. The method for improving the yield strength and hardness of rail transit vehicle wheel hubs according to claim 9, characterized in that: The chain plate machine (2) includes a drive roller (15), a driven roller (16), multiple bearing rollers (17), a chain plate (18), a drive roller drive motor (19), the driven roller (16), and the bearing roller (17) are respectively installed on the chain plate machine frame. The chain plate (18) is fitted on the drive roller (15) and the driven roller (16). Multiple bearing rollers (17) are supported on the upper and lower parts of the chain plate (18). The drive roller (15) is connected to the drive roller drive motor (19). The chain plate machine (2) extends from a position near the quenching furnace to a position near the tempering furnace.

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