Steel rail medium-frequency induction welding heat treatment equipment based on carbon dioxide protection

Abstract

The utility model provides steel rail medium-frequency induction welding heat treatment equipment based on carbon dioxide protection, and the steel rail medium-frequency induction welding heat treatment equipment comprises a steel rail clamping mechanism, an induction heating mechanism and a lifting mechanism, the induction heating mechanism is connected with a middle shaft of the steel rail clamping mechanism through the lifting mechanism. Carbon dioxide atmosphere protection is adopted, oxidation of the butt joint face of a welding seam in the induction heating process can be effectively avoided, the performance of a connector can be improved, and welding internal defects are reduced. The atmosphere protection cover is made of a high-temperature-resistant material and can play a role in heat preservation and heat insulation in the heating process, and the heating and welding efficiency is improved. The steel rail clamp mechanisms are connected through the four shafts, the welding straightness of the steel rail can be guaranteed, the space for installing the middle of the induction heating mechanism can be met, and the appearance quality of a connector can be improved.

Description

Technical Field

[0001] This utility model belongs to the field of railway rail welding and heat treatment technology, and particularly relates to a medium-frequency induction welding heat treatment equipment for rails based on carbon dioxide protection. Background Technology

[0002] In my country, the welding of seamless railway rails mainly employs three techniques: flash welding, gas pressure welding, and aluminothermic welding.

[0003] Flash welding is a process in which resistance heat is generated by applying electricity to both ends of the rail and then pressing and forging to form a welded joint. It is currently the most widely used rail welding technology, but it also has problems such as difficulty in eliminating gray spot defects, long process debugging cycle, and easy environmental pollution.

[0004] Gas pressure welding is a welding method that uses gas flame heating to heat the joint and then pressurize it for upsetting. Its main disadvantages are that it requires a large amount of flammable and explosive gas, the joint quality is greatly affected by the gas source, and defects that are difficult to detect are likely to occur. In addition, the flame heating temperature cannot be accurately measured, making it difficult to achieve full automation and requiring high skill from the operators.

[0005] Aluminothermic welding is a welding method that uses aluminothermic flux to generate an oxidation-reduction reaction, releasing heat to produce liquid metal that fills the weld gap. Its essence is a metal casting process, and the joint quality and performance are not as good as the two welding methods mentioned above.

[0006] The basic principle of medium-frequency induction heating is to place the metal workpiece in a copper coil, and apply an alternating magnetic field by applying an oscillating current of a certain frequency in the coil, thereby inducing eddy currents inside the metal for heating. In the field of rail welding, medium-frequency induction technology has been widely used in post-weld heat treatment of joints, but it has not yet been directly applied to rail welding. The medium-frequency induction welding and heat treatment method for rails based on carbon dioxide protection proposed in this utility model can overcome the shortcomings of existing technologies and effectively improve welding quality and efficiency. Utility Model Content

[0007] To overcome the shortcomings of the prior art, this utility model proposes a medium-frequency induction welding heat treatment device for rails based on carbon dioxide protection.

[0008] A medium-frequency induction welding heat treatment equipment for rails based on carbon dioxide protection includes a rail clamping mechanism, an induction heating mechanism, a lifting mechanism, an electrical control system, a medium-frequency power supply, a hydraulic pump station, a chiller unit, a carbon dioxide supply system, and an air cooling system. The induction heating mechanism is installed in the middle of the rail clamping mechanism and is connected to the central axis of the rail clamping mechanism through the lifting mechanism.

[0009] The induction heating mechanism includes an induction coil, a coil base, a carbon dioxide atmosphere protective cover, a transformer, a frame, and opening / closing cylinders. The induction coil consists of two parts, left and right, welded from hollow copper tubing and machined into a shape similar to the cross-section of the rail. The left and right parts of the induction coil are respectively fixed to the left and right parts of the coil base and separated by an insulating plate. The carbon dioxide atmosphere protective cover consists of two parts, respectively fixed to the left and right parts of the coil base, and wraps the entire induction coil and the rail joint. The left and right parts of the two coil bases are hinged to the frame by opening / closing cylinders. The extension and retraction of the cylinders can realize the opening and closing of the coil bases, thereby realizing the opening and closing of the left and right induction coils. The transformer is fixed to the frame, and the secondary winding of the transformer is connected to the induction coil through two busbars to form a single-turn induction circuit.

[0010] The lifting mechanism includes a motor, a lead screw, a lead screw nut, a guide rail, a slider, and a fixed plate. The motor is fixed on the fixed plate, and the motor and the lead screw are connected by a coupling. The lead screw and the fixed plate are connected by a bearing. The guide rail is fixed on the fixed plate, and the lead screw nut and the slider are fixed on the frame. The rotation of the motor drives the lead screw to rotate, which in turn drives the induction heating mechanism to achieve linear motion in the vertical direction.

[0011] The rail clamping mechanism includes a left clamp, a right clamp, two upsetting shafts, and two guide shafts. The left and right clamps are connected by the two upsetting shafts and the two guide shafts, ensuring both the straightness of the rail welding and sufficient space for the induction heating mechanism to be installed in the middle. One end of the upsetting shaft passes through the right clamp and connects to the upsetting cylinder, while the other end is fixed to the left clamp. One end of the guide shaft is fixed to the right clamp with a nut, and the other end passes through the left clamp. The extension and retraction of the upsetting cylinder drives the left clamp to move linearly along the guide shafts via the upsetting shafts, thereby achieving the upsetting of the rail joint.

[0012] The rail clamping mechanism further includes a pusher cylinder, a tool holder, and a pusher blade. The pusher cylinder is fixed to the end of the left clamp and connected to the tool holder through the cylinder shaft. The pusher blade is hung on the rail and fits against the tool holder. After the rail is upsetting, the force of the pusher cylinder pushes the pusher blade through the tool holder to remove the weld bead flash extruded from the joint.

[0013] The equipment also includes an electrical control system, a medium-frequency power supply, a hydraulic pump station, a chiller unit, a carbon dioxide supply system, and an air-cooling system. The rail clamping mechanism and the induction heating mechanism constitute the head section of the rail induction welding machine. The rail clamping mechanism performs functions such as rail web clamping, upsetting, and stub removal. The induction heating mechanism forms a closed magnetic field to provide a heat source. The electrical control system uses a PLC programmable controller to control the actions of each part of the mechanism and monitors various sensors within the system. The medium-frequency power supply provides heating energy to the induction coil through IGBT inverter and series resonance. The hydraulic pump station connects to the head cylinder to provide kinetic energy for clamping and upsetting actions. The chiller unit provides cooling for the induction coil and other heating components. The carbon dioxide supply system provides a carbon dioxide atmosphere for protection during the welding process. The air-cooling system provides a gas source for the heat treatment process, used to quickly reduce the joint temperature, achieve under-speed quenching, and improve the surface hardness of the joint.

[0014] Each of the two coil holders is equipped with 15 small nozzles, which are connected to a gas pipe connector through internal orifices, and then to a carbon dioxide supply system and an air-cooling system via gas pipes. During welding, the coil holders and the carbon dioxide protective cover form a relatively closed cavity around the rail joint. Carbon dioxide is injected into the cavity through the small nozzles to create an inert gas protection, preventing oxidation and defects at the weld joint surface during heating. During heat treatment, the gas pipes are switched to connect to the air-cooling system. After heating to the set temperature, the joint is rapidly cooled by blowing air through the small nozzles.

[0015] The carbon dioxide atmosphere protective cover is made of high-temperature resistant materials, including but not limited to graphite plates, mica plates, and asbestos cloth; the carbon dioxide atmosphere protective cover also plays a role in heat preservation and insulation during the heating process, thereby improving heating efficiency.

[0016] A medium-frequency induction welding device for rails based on carbon dioxide protection, the method comprising:

[0017] Step 1: Grind and remove rust from the side of the end face of the rail joint to be welded, and smooth the mating surface by end grinding or end milling.

[0018] Step 2: Use a rail clamping device to clamp and center the rail to be welded, and apply force with an upsetting cylinder to make the mating surfaces fit tightly.

[0019] Step 3: The induction coil adopts an openable and closing structure and is installed in the middle of the rail clamping device. It is lowered to the mating surface of the rail to be welded, and then the opening and closing cylinder is used to close the coil to form a closed loop around the rail.

[0020] Step 4: Control the valve to open the carbon dioxide supply system and inject gas into the carbon dioxide atmosphere protective hood through the small nozzle; it is required to start injecting gas 30 seconds before welding, with a carbon dioxide purity of not less than 99.5% and a flow rate of 5-15L / min;

[0021] Step 5: Start the intermediate frequency power supply to perform induction heating on the rail joint, and monitor the heating temperature throughout the process with a temperature measuring instrument;

[0022] Step Six: During the heating process, the upsetting cylinder is always under pressure, and the carbon dioxide injection flow rate is gradually reduced. When the temperature reaches 800-900℃, the carbon dioxide supply is stopped.

[0023] Step 7: When the set welding temperature (1200℃~1300℃) is reached, the intermediate frequency power supply is turned off. The upsetting cylinder accelerates and pressurizes the rail to be welded, causing the butt joint surface to close and the weld bead to be squeezed out. At the same time, the induction coil opens and rises.

[0024] Step 8: The rail weld removal mechanism removes the weld bead;

[0025] Step 9: The induction heating mechanism descends and closes again, the control valve opens the air cooling system, and compressed air is sprayed through small nozzles toward the weld rail head and rail web, etc., and the air spraying stops after the temperature drops below 400°C.

[0026] Step 10: Restart the medium frequency power supply to heat the welded joint to about 900℃ to complete the post-weld heat treatment, so as to refine the grain structure and improve the toughness and strength of the joint.

[0027] Step 11: The air-cooling system is turned on again, and compressed air is used to perform sub-speed quenching on the joint surface to improve the surface hardness of the joint.

[0028] Step 12: Finally, open the induction coil, release the rail clamping device from the rail, and then perform post-weld deburring, grinding, and other treatments.

[0029] This invention employs a carbon dioxide atmosphere protection system, which effectively prevents oxidation of the weld joint surface during induction heating, thus improving joint performance and reducing internal welding defects. The atmosphere protection cover is made of high-temperature resistant material, providing thermal insulation during heating and improving heating and welding efficiency. The rail clamping mechanism, connected by four shafts, ensures the straightness of the welded rail while accommodating the space required for installation in the center of the induction heating mechanism, contributing to improved joint appearance quality. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of an overall medium-frequency induction welding heat treatment equipment for rails based on carbon dioxide protection.

[0031] Figure 2 This is a schematic diagram of the structure of a medium-frequency induction welding heat treatment equipment for steel rails.

[0032] Figure 3 This is a schematic diagram of the induction heating mechanism.

[0033] Figure 4This is a schematic diagram of the coil opening structure of the induction heating mechanism.

[0034] Figure 5 This is a schematic diagram of the rail clamping mechanism.

[0035] Figure 6 A schematic diagram of the internal structure for carbon dioxide injection and air jetting.

[0036] Figure 7 This is a schematic diagram showing the distribution of small nozzles on the coil holder. Detailed Implementation

[0037] The following is a detailed description of a medium-frequency induction welding heat treatment device for rails based on carbon dioxide protection, provided by this utility model, with reference to the accompanying drawings and specific embodiments.

[0038] Appendix Figure 1-7 As shown, a medium-frequency induction welding heat treatment equipment for rails based on carbon dioxide protection includes a rail clamping mechanism 1, an induction heating mechanism 2, a lifting mechanism 5, an electrical control system, a medium-frequency power supply, a hydraulic pump station, a chiller unit, a carbon dioxide supply system, and an air cooling system. The induction heating mechanism 2 is installed in the middle part 1 of the rail clamping mechanism, and the induction heating mechanism 2 is connected to the central axis of the rail clamping mechanism 1 through the lifting mechanism 5.

[0039] The induction heating mechanism 2 includes an induction coil 6, a coil base 7, a carbon dioxide atmosphere protective cover 8, a transformer 9, a frame 10, and an opening and closing hydraulic cylinder 11. The induction coil 6 consists of two parts, left and right, which are made of hollow copper tubes welded and processed into a shape similar to the cross-section of the rail. The left and right parts of the induction coil 6 are respectively fixed on the left and right parts of the coil base 7 and separated by an insulating plate 14. The carbon dioxide atmosphere protective cover 8 consists of two parts, which are respectively fixed on the left and right parts of the coil base 7 and wrap the entire induction coil 6 and the rail joint. The left and right parts of the two coil bases 7 are respectively hinged to the frame 10 through the opening and closing hydraulic cylinder 11. The extension and retraction of the hydraulic cylinder can realize the opening and closing of the coil base, thereby realizing the opening and closing of the left and right induction coils. The transformer 9 is fixed on the frame 10. The secondary winding of the transformer 9 is connected to the induction coil through two busbars 13 to form a single-turn induction circuit.

[0040] The lifting mechanism 5 includes a motor 15, a lead screw 16, a lead screw nut 17, a guide rail 18, a slider 19, and a fixed plate 20. The motor 15 is fixed on the fixed plate 20. The motor 15 is connected to the lead screw 16 through a coupling. The lead screw 16 is connected to the fixed plate 20 through a bearing. The guide rail 18 is fixed on the fixed plate 20. The lead screw nut 17 and the slider 19 are fixed on the frame 10. The rotation of the motor 15 drives the lead screw 16 to rotate, which in turn drives the induction heating mechanism 2 to achieve linear motion in the vertical direction.

[0041] The rail clamping mechanism 1 includes a left clamp 21, a right clamp 22, two upsetting shafts 23, and two guide shafts 24. The left clamp 21 and right clamp 22 are connected by the two upsetting shafts 23 and the two guide shafts 24, ensuring both the straightness of the rail welding and sufficient space for the induction heating mechanism. One end of the upsetting shaft 23 passes through the right clamp 22 and connects to the upsetting cylinder 25, while the other end is fixed to the left clamp 21. One end of the guide shaft 24 is fixed to the right clamp 22 by a nut 26, and the other end passes through the left clamp 21. The extension and retraction of the upsetting cylinder can drive the left clamp to move linearly along the guide shafts via the upsetting shafts, thereby achieving the upsetting of the rail joint.

[0042] The rail clamping mechanism clamps the ends of the first rail 3 and the second rail 4, and brings the mating surfaces together directly below the induction heating mechanism 2; the induction heating mechanism 2 opens and lowers to heat the rail mating surfaces.

[0043] The rail clamping mechanism 1 also includes a pusher cylinder 27, a tool holder 28, and a pusher blade 29. The pusher cylinder 27 is fixed to the end of the left clamp 21 and is connected to the tool holder 28 through the cylinder shaft. The pusher blade 29 is hung on the rail and fits against the tool holder 28. After the rail is upsetting, the force of the pusher cylinder 27 pushes the pusher blade 29 through the tool holder 28 to remove the weld bead flash extruded from the joint.

[0044] The equipment also includes an electrical control system, a medium-frequency power supply, a hydraulic pump station, a chiller unit, a carbon dioxide supply system, and an air-cooling system. The rail clamping mechanism 1 and the induction heating mechanism 2 constitute the head section of the rail induction welding machine. The rail clamping mechanism 1 performs rail web clamping, upsetting, and end-removal functions, while the induction heating mechanism 2 forms a closed magnetic field to provide a heat source. The electrical control system uses a PLC programmable controller to control the actions of each part of the mechanism and monitors all sensors within the system. The medium-frequency power supply provides heating energy to the induction coil through IGBT inverter and series resonance. The hydraulic pump station connects to the head cylinder to provide kinetic energy for clamping, upsetting, and other actions. The chiller unit provides cooling for the induction coil and other heating components. The carbon dioxide supply system provides a carbon dioxide atmosphere for protection during the welding process. The air-cooling system provides a gas source for the heat treatment process, used to quickly reduce the joint temperature, achieve under-speed quenching, and improve the surface hardness of the joint.

[0045] Each of the two coil seats 7 is equipped with 15 small nozzles 30. The small nozzles are connected to the air pipe connector 31 through their internal apertures, and then connected to the carbon dioxide supply system and the air cooling system through the air pipe 32. The coil seats 7 and the carbon dioxide protective cover (8) form a relatively closed cavity 33 around the rail joint. Carbon dioxide is injected into the cavity through the small nozzles 30 to form an inert gas protection, which can prevent the weld joint surface from being oxidized and forming defects during the heating process. During the heat treatment process, the air pipe is switched to be connected to the air cooling system. After heating to the required temperature, the joint is rapidly cooled by blowing air through the small nozzles.

[0046] The carbon dioxide atmosphere protective cover is made of high-temperature resistant materials, including but not limited to graphite plates, mica plates, and asbestos cloth; the carbon dioxide atmosphere protective cover also plays a role in heat preservation and insulation during the heating process, thereby improving heating efficiency.

[0047] A medium-frequency induction welding heat treatment device for rails based on carbon dioxide protection, the method comprising:

[0048] Step 1: Grind and remove rust from the side of the end face of the rail joint to be welded, and smooth the mating surface by end grinding or end milling.

[0049] Step 2: Use a rail clamping device to clamp and center the rail to be welded, and apply force with an upsetting cylinder to make the mating surfaces fit tightly.

[0050] Step 3: The induction coil adopts an openable and closing structure and is installed in the middle of the rail clamping device. It is lowered to the mating surface of the rail to be welded, and then the opening and closing cylinder is used to close the coil to form a closed loop around the rail.

[0051] Step 4: Control the valve to open the carbon dioxide supply system and inject gas into the carbon dioxide atmosphere protective hood through the small nozzle; it is required to start injecting gas 30 seconds before welding, with a carbon dioxide purity of not less than 99.5% and a flow rate of 5-15L / min;

[0052] Step 5: Start the intermediate frequency power supply to perform induction heating on the rail joint, and monitor the heating temperature throughout the process with a temperature measuring instrument;

[0053] Step Six: During the heating process, the upsetting cylinder is always under pressure, and the carbon dioxide injection flow rate is gradually reduced. When the temperature reaches 800-900℃, the carbon dioxide supply is stopped.

[0054] Step 7: When the set welding temperature (1200℃~1300℃) is reached, the intermediate frequency power supply is turned off. The upsetting cylinder accelerates and pressurizes the rail to be welded, causing the butt joint surface to close and the weld bead to be squeezed out. At the same time, the induction coil opens and rises.

[0055] Step 8: The rail weld removal mechanism removes the weld bead;

[0056] Step Nine: The induction heating mechanism descends and closes again, the control valve opens the air cooling system, and compressed air is sprayed through small nozzles onto the weld seam rail head and rail web, etc., and the temperature drops to 400 degrees Celsius.

[0057] Stop blowing air when the temperature drops below ℃.

[0058] Step 10: Restart the medium frequency power supply to heat the welded joint to about 900℃ to complete the post-weld heat treatment, so as to refine the grain structure and improve the toughness and strength of the joint.

[0059] Step 11: The air-cooling system is turned on again, and compressed air is used to perform sub-speed quenching on the joint surface to improve the surface hardness of the joint.

[0060] Step 12: Finally, open the induction coil, release the rail clamping device from the rail, and then perform post-weld deburring, grinding, and other treatments.

[0061] Finally, it should be noted that the above embodiments are only used to describe the technical solutions of this utility model and not to limit the technical methods. This utility model can be extended to other modifications, changes, applications and embodiments in application, and therefore all such modifications, changes, applications and embodiments are considered to be within the spirit and teachings of this utility model.

Claims

1. A medium-frequency induction welding heat treatment device for rails based on carbon dioxide protection, characterized in that, The rail medium-frequency induction welding equipment includes a rail clamping mechanism (1), an induction heating mechanism (2), a lifting mechanism (5), an electrical control system, a medium-frequency power supply, a hydraulic pump station, a chiller unit, a carbon dioxide supply system, and an air-cooling system. The induction heating mechanism (2) is installed in the middle of the rail clamping mechanism (1), and the induction heating mechanism (2) is connected to the central axis of the rail clamping mechanism (1) through the lifting mechanism (5).

2. The rail medium-frequency induction welding heat treatment equipment based on carbon dioxide protection according to claim 1, characterized in that, The induction heating mechanism (2) includes an induction coil (6), a coil base (7), a carbon dioxide atmosphere protection cover (8), a transformer (9), a frame (10), and an opening and closing cylinder (11). The induction coil (6) consists of two parts, which are welded from hollow copper tubes and processed into a shape similar to the cross-section of the rail. The left and right parts of the induction coil (6) are respectively fixed on the left and right parts of the coil base (7) and separated by an insulating plate (14). The carbon dioxide atmosphere protection cover (8) consists of two parts, which are respectively fixed on the left and right parts of the coil base (7) and wrap the entire induction coil (6) and the rail joint. The left and right parts of the two coil bases (7) are respectively hinged to the frame (10) by the opening and closing cylinder (11). The extension and retraction of the cylinder can realize the opening and closing of the coil base, thereby realizing the opening and closing of the left and right induction coils. The transformer (9) is fixed on the frame (10). The secondary of the transformer (9) is connected to the induction coil through two busbars (13) to form a single-turn induction circuit.

3. The rail medium-frequency induction welding heat treatment equipment based on carbon dioxide protection according to claim 1, characterized in that, The lifting mechanism (5) includes a motor (15), a lead screw (16), a lead screw nut (17), a guide rail (18), a slider (19), and a fixed plate (20). The motor (15) is fixed on the fixed plate (20), the motor (15) and the lead screw (16) are connected by a coupling, the lead screw (16) and the fixed plate (20) are connected by a bearing, the guide rail (18) is fixed on the fixed plate (20), and the lead screw nut (17) and the slider (19) are fixed on the frame (10). The rotation of the motor (15) drives the lead screw (16) to rotate, so that the lead screw nut (17) drives the induction heating mechanism (2) to achieve linear motion in the vertical direction.

4. The medium-frequency induction welding heat treatment equipment for rails based on carbon dioxide protection according to claim 1, characterized in that, The rail clamping mechanism (1) includes a left clamp (21), a right clamp (22), two upsetting shafts (23), and two guide shafts (24). The left clamp (21) and the right clamp (22) are connected by the two upsetting shafts (23) and the two guide shafts (24). One end of the upsetting shaft (23) passes through the right clamp (22) and connects to the upsetting cylinder (25), while the other end of the upsetting shaft (23) is fixed on the left clamp (21). One end of the guide shaft (24) is fixed on the right clamp (22) by a nut (26), while the other end of the guide shaft (24) passes through the left clamp (21).

5. The medium-frequency induction welding heat treatment equipment for rails based on carbon dioxide protection according to claim 1, characterized in that, The rail clamping mechanism (1) also includes a push cylinder (27), a tool holder (28), and a push knife (29). The push cylinder (27) is fixed at the end of the left clamp (21) and connected to the tool holder (28) through the cylinder shaft. The push knife (29) is hung on the rail and fits against the tool holder (28). After the rail is upsetting, the force of the push cylinder (27) pushes the push knife (29) through the tool holder (28) to cut off the weld bead flash extruded from the joint.

6. The medium-frequency induction welding heat treatment equipment for rails based on carbon dioxide protection according to claim 1, characterized in that, The rail clamping mechanism (1) and the induction heating mechanism (2) constitute the head part of the rail induction welding machine. The rail clamping mechanism (1) realizes the functions of rail web clamping, upsetting and pushing, and the induction heating mechanism (2) forms a closed magnetic field to provide a heating source. The electrical control system is controlled by a PLC programmable controller to control the actions of each part of the mechanism and monitor each sensor in the system at the same time. The intermediate frequency power supply provides heating power to the induction coil through IGBT inversion and series resonance; the hydraulic pump station is connected to the head cylinder to provide kinetic energy for the clamping and upsetting action; the chiller unit provides cooling for the induction coil and other heat-generating components; the carbon dioxide supply system provides carbon dioxide atmosphere protection for the welding process; the air cooling system provides air source for the heat treatment process to quickly reduce the joint temperature, achieve under-speed quenching, and improve the surface hardness of the joint.

7. The rail medium-frequency induction welding heat treatment equipment based on carbon dioxide protection according to claim 2, characterized in that, Each of the two coil seats (7) is provided with 15 small nozzles (30). The small nozzles are connected to the air pipe connector (31) through the internal aperture, and then connected to the carbon dioxide supply system and the air cooling system through the air pipe (32). The coil seat (7) and the carbon dioxide protective cover (8) form a relatively closed cavity (33) around the rail joint. Carbon dioxide is injected into the cavity through the small nozzles (30) to form an inert gas protection.

8. The rail medium-frequency induction welding heat treatment equipment based on carbon dioxide protection according to claim 2, characterized in that, The carbon dioxide atmosphere protection cover (8) is made of high-temperature resistant materials, including but not limited to graphite plate, mica plate, and asbestos cloth; the carbon dioxide atmosphere protection cover (8) also plays a role in heat preservation and heat insulation during the heating process, thereby improving heating efficiency.

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