Efficient motorcycle exhaust silencer welding method

Abstract

The invention discloses an efficient welding method for an exhaust silencer of a motorcycle. According to the invention, breakthrough improvement of manufacturing quality and efficiency is realized through multi-dimensional technical innovation. A high-frequency electromagnetic field resonance stress relief technology is creatively introduced, the metal crystallization behavior is intervened in real time in the welding process, and the thermodynamic equilibrium state of traditional welding is fundamentally reconstructed. Electromagnetic energy directly acts on molten metal in a microscopic particle vibration mode, lattice defects are promoted to be spontaneously repaired in the liquid stage, the deformation cracking risk caused by thermal stress accumulation in a traditional technology is avoided, and microstructure optimization is more synchronously completed. According to the dynamic energy field regulation and control means, the welding strength and toughness of the complex curved surface structure of the silencer are synergistically enhanced, a uniform and compact fine grain structure is formed in a welding seam area, the anti-fatigue performance of a product under the impact of high-temperature tail gas is remarkably improved, meanwhile, the necessary annealing procedure after traditional welding is integrated into in-situ treatment, and the production efficiency is improved. And the production period is greatly shortened.

Description

Technical Field

[0001] The present invention belongs to the technical field of motorcycle exhaust production, and specifically relates to an efficient welding method for motorcycle exhaust mufflers. Background Art

[0002] The motorcycle exhaust muffler is an important part of the motorcycle exhaust system, mainly used to reduce the noise of the engine's exhaust gas, reduce environmental pollution and the impact on riders and surrounding people. It is usually installed at the end of the exhaust pipe, and through the ingenious design of the internal structure, such as partitions, sound-absorbing materials, etc., to attenuate the sound wave energy, so as to achieve the purpose of noise reduction. And the welding of the motorcycle exhaust muffler is a key process in the manufacturing process, which requires welding various components of the muffler, such as the outer shell, end cover, internal partition, etc., firmly together through the welding process. The welding process requires precise control of welding parameters, such as current, voltage, welding speed, etc., to ensure the strength and tightness of the weld seam and prevent exhaust leakage. At the same time, the welding quality directly affects the appearance and durability of the muffler, so experienced welders are required to operate and advanced welding equipment and technologies are adopted to ensure product quality. High-quality welding technology is the basis for manufacturing high-performance motorcycle exhaust mufflers, and is of great significance for improving the overall performance of motorcycles and the user experience.

[0003] However, the conventional welding process cannot synchronously regulate the microstructure of the molten pool, resulting in a sudden change in the mechanical properties gradient in the weld area. At the same time, the insufficient surface treatment accuracy is prone to cause an increase in exhaust back pressure and noise resonance, and the overall structural reliability and service life are difficult to meet the requirements of the extreme working conditions of high-performance motorcycles. Summary of the Invention

[0004] The purpose of the present invention is to provide an efficient welding method for motorcycle exhaust mufflers in order to solve the above-mentioned problems.

[0005] The technical scheme adopted by the present invention is as follows: An efficient welding method for motorcycle exhaust mufflers, the method comprising the following steps:

[0006] S1: Using laser cutting technology to perform high-precision bevel processing on the muffler outer shell and inner liner assembly;

[0007] S2: Using an ultrasonic cleaning device to perform nano-level oxide layer stripping treatment on the welding surface;

[0008] S3: Designing a three-dimensional adjustable magnetic fixture to realize the spatial positioning of the multi-section muffler;

[0009] S4: Using a dual-robot collaborative welding system to perform phase-synchronized pulsed TIG welding;

[0010] S5: Introducing the principle of high-frequency electromagnetic field resonance in the partition welding process to eliminate residual stress;

[0011] S6: Monitor the molten pool morphology in real time through an infrared thermal imager and feedback to adjust the welding parameters;

[0012] S7: Implement a layered gradient annealing process to control the phase transformation of the metallographic structure in the welding area;

[0013] S8: Use a multi-axis linkage polishing robot to complete the streamline treatment of the weld bead surface;

[0014] S9: Conduct airtightness verification using a helium mass spectrometry leak detection system based on acoustic modal analysis.

[0015] In a preferred embodiment, in step S1, a 2000W fiber laser is used to cut the muffler housing and the inner tank assembly. The cutting speed is set at 4 m / min, and the auxiliary gas is nitrogen with a purity of 99.99%. The air pressure is maintained at 0.8 MPa. A groove track with an accuracy of 0.1 mm is generated through three-dimensional scanning reverse modeling. The groove angle is controlled at 35° ± 0.5°, and the root face thickness is 1.2 mm to ensure the consistency of the subsequent welding penetration. During the processing, the laser focus position is monitored in real time. When the offset exceeds ±0.05 mm, the automatic compensation system is triggered, and the surface roughness of the cut is controlled within Ra3.2 μm.

[0016] In a preferred embodiment, in step S2, a 40kHz high-frequency ultrasonic generator is configured. The bath solution is an alkaline nano-cleaning agent with a pH of 12.5, and the solution temperature is kept constant at 65°C ± 2°C. The workpiece is immersed in the cleaning solution for 15 minutes, and a bubble group with a diameter less than 100 nm is generated through the cavitation effect to completely peel off the oxides and oil stains on the welding surface. After cleaning, it is rinsed with deionized water at 80°C and processed by a compressed air cyclone drying system. The detection value of the surface residue is lower than 5 mg / m 2 , and the contact angle test meets the fully hydrophilic standard.

[0017] In a preferred embodiment, in step S3, a neodymium iron boron permanent magnet is used to construct a six-degree-of-freedom adjustable fixture system. The single-point magnetic suction force is ≥800 N, and the spatial positioning repeat accuracy is ±0.02 mm. A clamping scheme is generated according to the three-dimensional point cloud data of the muffler, and the magnetic force distribution is dynamically adjusted through an electromagnetic coil array to achieve zero-deformation clamping of complex curved surfaces with a radius of curvature less than 50 mm. During the positioning process, a laser interferometer is used for real-time calibration, and the cumulative error of the multi-section component assembly is controlled within 0.1 mm.

[0018] In a preferred embodiment, in step S4, two six-axis robots are equipped with digital pulsed TIG torches, and the collaborative motion trajectory accuracy is ±0.05 mm. The welding current is set to a base value of 120 A / peak value of 180 A, the pulse frequency is 2 Hz, the argon-helium mixed shielding gas ratio is 7:3, and the flow rate is 15 L / min. The phase difference between the two torches is strictly maintained at 180°, the overlapping amount of the arc action area is controlled within the range of 20% of the weld width, and the welding speed is 0.8 m / min. A spectral analyzer is used to monitor the molten pool composition online, and the ferrite content is real-time regulated within the ideal range of 8% - 12%.

[0019] In a preferred embodiment, in step S5, the electromagnetic wave frequency band: a specific frequency range of 200 kHz to 300 kHz is adopted. The magnetic field intensity controls the alternating magnetic field intensity in the range of 0.5 Tesla to 1.2 Tesla, and the Hall sensor is used to monitor the magnetic field distribution uniformity in real time. The electromagnetic field action starts synchronously with the welding arc and terminates 50 milliseconds before the molten pool is completely solidified, covering the whole process of the metal liquid-solid phase transformation. When applying the electromagnetic field, the substrate temperature is strictly controlled within the range of 50°C below the solidus temperature of the material to 20°C above the liquidus temperature to avoid abnormal grain coarsening.

[0020] The specific implementation process includes the following steps:

[0021] S1. Pre-calibration of the electromagnetic field generator: According to the magnetic permeability characteristics of the muffler material (such as 409L stainless steel), the optimal frequency matching point is determined by an impedance analyzer, and the magnetic field gradient parameters are preset.

[0022] S2. Collaborative control during the welding process: Start the annular electromagnetic coil array within 0.2 seconds after the TIG torch arcs, and wrap the molten pool area coaxially to ensure that the energy field coverage diameter is more than 1.5 times the weld width.

[0023] S3. Dynamic frequency tuning: Based on the infrared thermal imaging data of the molten pool, the electromagnetic frequency is adjusted in real time by the fuzzy PID algorithm. When the detected temperature gradient exceeds 15°C / mm, the frequency is automatically increased to 280 kHz to enhance the stress dispersion effect.

[0024] S4. Multi-physical field coupling effect: The electromagnetic field drives the dislocations inside the metal to vibrate at a high frequency of the order of 10^4 times per second, triggering the dynamic recrystallization process, so that the microcracks generated by the grain boundary slip heal themselves under the action of surface tension.

[0025] S5. Post-effect monitoring and verification: Use the electron backscatter diffraction technology to analyze the processed area, and confirm that the dislocation density is reduced to less than 30% of that of conventional welding, and the standard deviation of the residual stress distribution is less than 50 MPa.

[0026] In a preferred embodiment, in step S6, a 640×512 pixel uncooled infrared focal plane detector is equipped, with a thermal sensitivity of 0.03 °C and a sampling rate of 100 Hz. A three-dimensional model of the molten pool temperature field is established. When the temperature gradient at the tail of the molten pool is detected to exceed 250 °C / mm, the welding current is automatically increased by 3% - 5%. Characteristic temperature thresholds are set for different wall thickness regions. The 1.5 mm thin plate area is locked at 1120 °C ± 20 °C, and the 3 mm thick plate area allows a fluctuation of 1350 °C ± 30 °C. When the range is exceeded, an audible and visual alarm is immediately triggered and the welding is interrupted.

[0027] In a preferred embodiment, in step S7, three-stage heat treatment is implemented in a vacuum annealing furnace: in the initial stage, it is heated to 850 °C at a rate of 20 °C / min and held for 15 minutes; in the middle stage, it is slowly cooled to 650 °C at a rate of 5 °C / min and held at a constant temperature for 30 minutes; in the final stage, a nitrogen-hydrogen mixed gas is introduced and it is rapidly cooled to 480 °C at a rate of 50 °C / s. Each layer of weld is individually equipped with a heating coil, and the deviation of the temperature field uniformity is less than ±5 °C. The residual stress elimination rate is verified by an X-ray diffractometer to be ≥85%, and the width of the hardness gradient transition zone is compressed to within 0.8 mm.

[0028] In a preferred embodiment, in step S8, a seven-axis linkage robotic arm is used to carry a Φ6 mm diamond-coated grinding head, with a spindle speed of 20000 rpm and a feed speed of 1.2 m / min. An adaptive polishing path is generated based on the three-dimensional morphology data of the weld bead, and the axial pressure is dynamically controlled in the range of 0.5 N - 3 N. In the rough polishing stage, a 600-mesh abrasive belt is used to remove 0.2 mm of the remaining height, and in the fine polishing stage, a 3000-mesh fiber wheel is switched for mirror finishing. The surface roughness is reduced from the original Ra6.3 μm to Ra0.2 μm, and the contour error is less than 0.05 mm.

[0029] In a preferred embodiment, in step S9, an ultimate vacuum environment of 5×10^-4 Pa is established in a vacuum chamber, and 30% helium-nitrogen mixed tracer gas is injected. The natural frequency of the muffler is collected through a 32-channel acoustic sensor array, and the suspected leakage points are located by comparing the theoretical modal analysis results. The detection sensitivity of the helium mass spectrometer reaches 5×10^-9 Pa·m 3 / s, and the scanning probe moves along a preset spiral trajectory at a speed of 10 mm / s for detection. The judgment criterion is that the leakage rate of the whole device is less than 1×10^-7 Pa·m 3 / s, and at the same time, the structural integrity is verified through a 100 - 5000 Hz swept-frequency vibration test.

[0030] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are:

[0031] 1. In the present invention, breakthrough improvements in manufacturing quality and efficiency are achieved through multi-dimensional technological innovations. The creatively introduced high-frequency electromagnetic field resonance stress relief technology intervenes in the metal crystallization behavior in real time during the welding process, fundamentally reconstructing the thermodynamic equilibrium state of traditional welding. The electromagnetic energy directly acts on the molten metal in the form of microscopic particle vibrations, prompting the spontaneous repair of lattice defects in the liquid phase. This not only avoids the risk of deformation and cracking caused by the accumulation of thermal stress in traditional processes but also synchronously optimizes the microstructure. This dynamic energy field regulation method enables the coordinated enhancement of the welding strength and toughness of the complex curved surface structure of the muffler. A uniform and dense fine-grained structure is formed in the weld area, significantly improving the anti-fatigue performance of the product under the impact of high-temperature exhaust gas. At the same time, the necessary annealing process after traditional welding is integrated into in-situ treatment, greatly shortening the production cycle.

[0032] 2. In the present invention, the precise control of the penetration depth in the collaborative welding of dual robots, combined with the dynamic tuning of the electromagnetic field to eliminate stress concentration, and finally through gradient annealing and streamline polishing, the overall structure of the muffler exhibits excellent airtight integrity and surface durability. Particularly crucial is that the electromagnetic resonance technology breaks through the shackles of the performance attenuation in the heat-affected zone of traditional welding, enabling the corrosion resistance and anti-vibration performance of the thin-walled pipe fittings after welding to reach the level of forgings. While maintaining a lightweight design, the smoothness of the internal air flow channel and the uniformity of the thermal stress distribution of the finished muffler exceed the limits of conventional processes, effectively reducing the exhaust back pressure and suppressing resonance noise. The overall service life is increased to more than twice the industry standard, meeting the reliability requirements of high-performance motorcycles for the exhaust system under extreme working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the process principle of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0035] Embodiment:

[0036] Referring to Figure 1 , a welding method for an efficient motorcycle exhaust muffler, the method includes the following steps:

[0037] S1: Use laser cutting technology to perform high-precision groove machining on the muffler shell and inner liner components;

[0038] S2: Use an ultrasonic cleaning device to perform nano-level oxide layer stripping treatment on the welding surface;

[0039] S3: Design a three-dimensional adjustable magnetic fixture to achieve spatial positioning of the multi-section muffler;

[0040] S4: Implement phase-synchronized pulsed TIG welding using a dual-robot collaborative welding system;

[0041] S5: Introduce the principle of high-frequency electromagnetic field resonance in the partition welding process to eliminate residual stress;

[0042] S6: Real-time monitor the molten pool morphology through an infrared thermal imager and feedback to adjust the welding parameters;

[0043] S7: Implement a hierarchical gradient annealing process to control the transformation of the metallographic structure in the welding area;

[0044] S8: Use a multi-axis linkage polishing robot to complete the streamline treatment of the weld bead surface;

[0045] S9: Conduct airtightness verification using a helium mass spectrometry leak detection system based on acoustic modal analysis.

[0046] In step S1, a 2000W fiber laser is used to cut the muffler housing and inner liner assembly. The cutting speed is set at 4m / min, and the auxiliary gas is nitrogen with a purity of 99.99%. The air pressure is maintained at 0.8MPa. A groove trajectory with an accuracy of 0.1mm is generated through three-dimensional scanning reverse modeling. The groove angle is controlled at 35°±0.5°, and the root face thickness is 1.2mm to ensure the consistency of the subsequent welding penetration. During the processing, the position of the laser focus is monitored in real time. When the offset exceeds ±0.05mm, the automatic compensation system is triggered, and the surface roughness of the cut is controlled within Ra3.2μm.

[0047] In step S2, a 40kHz high-frequency ultrasonic generator is configured. The bath solution is an alkaline nano-cleaning agent with a pH of 12.5, and the solution temperature is kept constant at 65℃±2℃. The workpiece is immersed in the cleaning solution for 15 minutes, and a bubble group with a diameter less than 100nm is generated through the cavitation effect to completely peel off the oxides and oil stains on the welding surface. After cleaning, it is rinsed with deionized water at 80℃ and processed by a compressed air cyclone drying system. The detection value of the surface residue is lower than 5mg / m 2 , and the contact angle test meets the full hydrophilicity standard.

[0048] In step S3, a neodymium iron boron permanent magnet is used to construct a six-degree-of-freedom adjustable fixture system. The single-point magnetic suction force is ≥800N, and the spatial positioning repeat accuracy is ±0.02mm. According to the three-dimensional point cloud data of the muffler, a clamping scheme is generated, and the magnetic force distribution is dynamically adjusted through an electromagnetic coil array to achieve zero-deformation clamping of complex curved surfaces with a curvature radius less than 50mm. During the positioning process, a laser interferometer is used for real-time calibration, and the cumulative error of the multi-section component assembly is controlled within 0.1mm.

[0049] In step S4, two six-axis robots are equipped with digital pulsed TIG torches, and the collaborative motion trajectory accuracy is ±0.05 mm. The welding current is set to a base value of 120 A / peak value of 180 A, the pulse frequency is 2 Hz, the argon-helium mixed shielding gas ratio is 7:3, and the flow rate is 15 L / min. The phase difference between the two torches is strictly maintained at 180°, the overlap of the arc action area is controlled within the range of 20% of the weld width, and the welding speed is 0.8 m / min. A spectral analyzer is used to online monitor the molten pool composition, and the ferrite content is real-time regulated within the ideal range of 8% - 12%.

[0050] In step S5, electromagnetic wave frequency band: a specific frequency range from 200 kHz to 300 kHz is adopted. The magnetic field intensity controls the alternating magnetic field intensity within the range of 0.5 Tesla to 1.2 Tesla, and the Hall sensor is used to real-time monitor the uniformity of the magnetic field distribution. The electromagnetic field action starts synchronously with the welding arc and terminates 50 milliseconds before the molten pool is completely solidified, covering the entire process of the metal liquid-solid phase transformation. When applying the electromagnetic field, the substrate temperature is strictly controlled within the range of 50°C below the solidus temperature of the material to 20°C above the liquidus temperature to avoid abnormal grain coarsening.

[0051] The specific implementation process includes the following steps:

[0052] S1. Pre-calibration of the electromagnetic field generator: According to the magnetic permeability characteristics of the muffler material (such as 409L stainless steel), the optimal frequency matching point is determined by an impedance analyzer, and the magnetic field gradient parameters are preset.

[0053] S2. Collaborative control during the welding process: The annular electromagnetic coil array is started within 0.2 seconds after the TIG torch arcs, and the molten pool area is wrapped in a coaxial manner to ensure that the energy field coverage diameter is more than 1.5 times the weld width.

[0054] S3. Dynamic frequency tuning: Based on the infrared thermal imaging data of the molten pool, the electromagnetic frequency is real-time adjusted by the fuzzy PID algorithm. When the detected temperature gradient exceeds 15°C / mm, the frequency is automatically increased to 280 kHz to enhance the stress dispersion effect.

[0055] S4. Multi-physical field coupling effect: The electromagnetic field drives the dislocations inside the metal to vibrate at a high frequency of the order of 10^4 times per second, triggering the dynamic recrystallization process, so that the microcracks generated by the grain boundary slip heal spontaneously under the action of surface tension.

[0056] S5. Post-effect monitoring and verification: The electron backscatter diffraction technology is used to analyze the processed area, and it is confirmed that the dislocation density is reduced to less than 30% of that of conventional welding, and the standard deviation of the residual stress distribution is less than 50 MPa.

[0057] In step S6, a non-cooled infrared focal plane detector with 640×512 pixels is equipped, having a thermal sensitivity of 0.03°C and a sampling rate of 100 Hz. A three-dimensional model of the molten pool temperature field is established. When the temperature gradient at the tail of the molten pool is detected to exceed 250°C / mm, the welding current is automatically increased by 3% - 5%. Characteristic temperature thresholds are set for different wall thickness regions. The 1.5 mm thin plate area locks at 1120°C ± 20°C, and the 3 mm thick plate area allows a fluctuation of 1350°C ± 30°C. When the range is exceeded, an audible and visual alarm is immediately triggered and the welding is interrupted.

[0058] In step S7, three-stage heat treatment is carried out in a vacuum annealing furnace: in the initial stage, it is heated to 850°C at a rate of 20°C / min and held for 15 minutes, in the middle stage, it is slowly cooled to 650°C at 5°C / min and held at a constant temperature for 30 minutes, and in the final stage, a nitrogen-hydrogen mixed gas is introduced and it is rapidly cooled to 480°C at 50°C / s. Each layer of weld is separately equipped with a heating coil, and the temperature field uniformity deviation is less than ±5°C. The residual stress elimination rate is verified by an X-ray diffractometer to be ≥85%, and the width of the hardness gradient transition zone is compressed to within 0.8 mm.

[0059] In step S8, a seven-axis linkage robotic arm is used to carry a Φ6 mm diamond-coated grinding head, with a spindle speed of 20000 rpm and a feed speed of 1.2 m / min. An adaptive polishing path is generated based on the three-dimensional weld bead topography data, and the axial pressure is dynamically controlled in the range of 0.5 N - 3 N. In the rough polishing stage, a 600-mesh abrasive belt is used to remove 0.2 mm of the remaining height, and in the fine polishing stage, a 3000-mesh fiber wheel is switched for mirror finishing. The surface roughness is reduced from the original Ra6.3 μm to Ra0.2 μm, and the contour error is less than 0.05 mm.

[0060] In step S9, an ultimate vacuum environment of 5×10^-4 Pa is established in a vacuum chamber, and 30% helium-nitrogen mixed tracer gas is injected. The natural frequency of the muffler is collected through a 32-channel acoustic sensor array, and the suspected leakage points are located by comparing with the theoretical modal analysis results. The detection sensitivity of the helium mass spectrometer reaches 5×10^-9 Pa·m 3 / s, and the scanning probe moves along a preset spiral trajectory at a speed of 10 mm / s for detection. The judgment criterion is that the leakage rate of the whole device is less than 1×10^-7 Pa·m 3 / s, and at the same time, the structural integrity is verified through a 100 - 5000 Hz swept-frequency vibration test.

[0061] It can be known from the above that:

[0062] In the present invention, breakthrough improvements in manufacturing quality and efficiency are achieved through multi-dimensional technological innovations. The creatively introduced high-frequency electromagnetic field resonance stress relief technology intervenes in the metal crystallization behavior in real time during the welding process, fundamentally reconstructing the thermodynamic equilibrium state of traditional welding. The electromagnetic energy directly acts on the molten metal in the form of microscopic particle vibrations, prompting the spontaneous repair of lattice defects in the liquid phase. This not only avoids the risk of deformation and cracking caused by the accumulation of thermal stress in traditional processes but also synchronously optimizes the microstructure. This means of dynamically regulating the energy field enables the coordinated enhancement of the welding strength and toughness of the complex curved surface structure of the muffler. A uniform and dense fine-grained structure is formed in the weld area, significantly improving the anti-fatigue performance of the product under the impact of high-temperature exhaust gas. At the same time, the necessary annealing process after traditional welding is integrated into in-situ treatment, greatly shortening the production cycle.

[0063] In the present invention, the precise control of the penetration depth in the collaborative welding of dual robots, combined with the dynamic tuning of the electromagnetic field to eliminate stress concentration, and finally through gradient annealing and streamline polishing, the overall structure of the muffler exhibits excellent airtight integrity and surface durability. Particularly crucial is that the electromagnetic resonance technology breaks through the shackles of the performance attenuation in the heat-affected zone of traditional welding, enabling the corrosion resistance and anti-vibration performance of the thin-walled pipe fittings after welding to reach the level of forgings. While maintaining the lightweight design, the smoothness of the internal air flow channel and the uniformity of the thermal stress distribution of the finished muffler exceed the limits of conventional processes, effectively reducing the exhaust back pressure and suppressing resonance noise. The overall service life is increased to more than twice the industry standard, meeting the reliability requirements of high-performance motorcycles for the exhaust system under extreme working conditions.

[0064] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the existence of additional identical elements in the process, method, article, or device comprising the element.

[0065] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An efficient welding method for motorcycle exhaust mufflers, characterized in that: The method includes the following steps: S1: Use laser cutting technology to perform high-precision beveling on the muffler shell and inner liner assembly; S2: Use an ultrasonic cleaning device to perform nano-level oxide layer stripping on the welding surface; S3: Design a three-dimensional adjustable magnetic fixture to achieve spatial positioning of the multi-section muffler; S4: Use a dual-robot collaborative welding system to perform pulsed TIG welding with phase synchronization; S5: Introduce the principle of high-frequency electromagnetic field resonance in the partition welding process to eliminate residual stress; S6: Use an infrared thermal imager to monitor the molten pool morphology in real time and feedback to adjust welding parameters; S7: Implement a hierarchical gradient annealing process to control the transformation of the metallographic structure in the welding area; S8: Use a multi-axis linkage polishing robot to complete the streamline treatment of the weld bead surface; S9: Perform airtightness verification based on a helium mass spectrometry leak detection system with acoustic modal analysis.

2. The high-efficiency welding method for a motorcycle exhaust muffler according to claim 1, characterized in that: In step S1, a 2000W fiber laser is used to cut the muffler shell and inner liner assembly. The cutting speed is set at 4m / min, and nitrogen with a purity of 99.99% is selected as the auxiliary gas, with the air pressure maintained at 0.8MPa; a bevel track with an accuracy of 0.1mm is generated through three-dimensional scanning reverse modeling. The bevel angle is controlled at 35°±0.5°, and the root face thickness is 1.2mm to ensure the consistency of the subsequent welding penetration depth; during the processing, the laser focus position is monitored in real time. When the offset exceeds ±0.05mm, the automatic compensation system is triggered, and the surface roughness of the cut is controlled within Ra3.2μm.

3. The high-efficiency welding method for a motorcycle exhaust muffler according to claim 1, wherein: In the step S2, a 40 kHz high-frequency ultrasonic generator is configured, the bath solution is an alkaline nano-cleaning agent with a pH of 12.5, and the solution temperature is kept constant at 65°C ± 2°C; the workpiece is immersed in the cleaning solution for 15 minutes, and a bubble group with a diameter less than 100 nm is generated through the cavitation effect to completely strip the oxides and oil stains on the welding surface; after cleaning, it is rinsed with deionized water at 80°C and processed by a compressed air cyclone drying system, and the detected value of the surface residue is lower than 5 mg / m 2 , and the contact angle test meets the complete hydrophilicity standard.

4. The high-efficiency welding method for a motorcycle exhaust muffler according to claim 1, wherein: In step S3, a neodymium iron boron permanent magnet is used to construct a six-degree-of-freedom adjustable fixture system, with a single-point magnetic suction force ≥800N and a spatial positioning repeat accuracy of ±0.02mm; a clamping scheme is generated based on the three-dimensional point cloud data of the muffler, and the magnetic force distribution is dynamically adjusted through an electromagnetic coil array to achieve zero-deformation clamping of complex curved surfaces with a radius of curvature less than 50mm; during the positioning process, a laser interferometer is used for real-time calibration, and the cumulative error of the multi-section component assembly is controlled within 0.1mm.

5. The high-efficiency welding method for a motorcycle exhaust muffler according to claim 1, characterized in that: In step S4, two six-axis robots are equipped with digital pulsed TIG welding torches, and the collaborative motion trajectory accuracy is ±0.05mm; the welding current is set at 120A base value / 180A peak value, the pulse frequency is 2Hz, the ratio of argon-helium mixed shielding gas is 7:3, and the flow rate is 15L / min; the phase difference between the two welding torches is strictly maintained at 180°, the overlap of the arc action area is controlled within 20% of the weld width, and the welding speed is 0.8m / min; a spectral analyzer is used to monitor the molten pool composition online, and the ferrite content is adjusted in real time within the ideal range of 8% - 12%.

6. The high-efficiency welding method for a motorcycle exhaust muffler according to claim 1, characterized in that: In step S5, the electromagnetic wave frequency band: a specific frequency range of 200 kHz to 300 kHz is adopted; the magnetic field strength controls the alternating magnetic field strength in the range of 0.5 Tesla to 1.2 Tesla, and the uniformity of the magnetic field distribution is monitored in real time through a Hall sensor; the electromagnetic field action starts synchronously with the welding arc and terminates 50 milliseconds before the molten pool completely solidifies, covering the entire process of the metal liquid-solid phase transformation; when applying the electromagnetic field, the substrate temperature is strictly controlled within the range of 50°C below the solidus line to 20°C above the liquidus line of the material to avoid abnormal grain coarsening; The specific implementation process includes the following steps: S1. Pre - calibration of the electromagnetic field generator: According to the magnetic permeability characteristics of the muffler material, the optimal frequency matching point is determined by an impedance analyzer, and the magnetic field gradient parameters are preset. S2. Cooperative control during welding: Start the annular electromagnetic coil array within 0.2 seconds after the TIG torch arcs, and wrap the molten pool area coaxially to ensure that the energy field coverage diameter is more than 1.5 times the width of the molten pool. S3. Dynamic frequency tuning: Based on the infrared thermal imaging data of the molten pool, the electromagnetic frequency is adjusted in real - time through the fuzzy PID algorithm. When the detected temperature gradient exceeds 15 °C / mm, the frequency is automatically increased to 280 kHz to enhance the stress dispersion effect. S4. Multi - physical - field coupling effect: The electromagnetic field drives the dislocations inside the metal to vibrate at a high frequency of the order of 10^4 times per second, triggering the dynamic recrystallization process, so that the micro - cracks generated by grain boundary slip heal themselves under the action of surface tension. S5. Post - effect monitoring and verification: The electron backscatter diffraction technique is used to analyze the processed area, and it is confirmed that the dislocation density is reduced to less than 30% of that of conventional welding, and the standard deviation of the residual stress distribution is less than 50 MPa.

7. The high-efficiency welding method for a motorcycle exhaust muffler according to claim 1, characterized in that: In step S6, a non - cooled infrared focal plane detector with 640×512 pixels and a thermal sensitivity of 0.03 °C and a sampling rate of 100 Hz is equipped; a three - dimensional model of the molten pool temperature field is established. When the temperature gradient at the tail of the molten pool is detected to exceed 250 °C / mm, the welding current is automatically increased by 3% - 5%; characteristic temperature thresholds are set for different wall - thickness regions, locked at 1120 °C ± 20 °C for the 1.5 - mm thin - plate area and allowed to fluctuate within 1350 °C ± 30 °C for the 3 - mm thick - plate area. When the range is exceeded, an audible and visual alarm is immediately triggered and the welding is interrupted.

8. The high-efficiency welding method for a motorcycle exhaust muffler according to claim 1, wherein: In step S7, three - stage heat treatment is implemented in a vacuum annealing furnace: in the initial stage, it is heated to 850 °C at a rate of 20 °C / min and held for 15 minutes, in the middle stage, it is slowly cooled to 650 °C at a rate of 5 °C / min and held at a constant temperature for 30 minutes, and in the final stage, a nitrogen - hydrogen mixed gas is introduced and it is rapidly cooled to 480 °C at a rate of 50 °C / s; each layer of weld is equipped with a heating coil separately, and the temperature field uniformity deviation is less than ±5 °C; the residual stress elimination rate is verified by an X - ray diffractometer to be ≥85%, and the width of the hardness gradient transition zone is compressed to within 0.8 mm.

9. The high-efficiency welding method for a motorcycle exhaust muffler according to claim 1, characterized in that: In step S8, a seven - axis linkage robotic arm is used to carry a Φ6 - mm diamond - coated grinding head with a spindle speed of 20000 rpm and a feed speed of 1.2 m / min; an adaptive polishing path is generated based on the three - dimensional morphology data of the weld bead, and the axial pressure is dynamically controlled in the range of 0.5 N - 3 N; in the rough polishing stage, a 600 - mesh abrasive belt is used to remove 0.2 - mm excess height, and in the fine polishing stage, a 3000 - mesh fiber wheel is switched for mirror finishing, reducing the surface roughness from the original Ra6.3 μm to Ra0.2 μm, and the contour error is less than 0.05 mm.

10. An efficient welding method for a motorcycle exhaust muffler according to claim 1, characterized in that: In the step S9, an ultimate vacuum environment of 5×10^-4 Pa is established in the vacuum chamber, and 30% helium-nitrogen mixed tracer gas is injected; the natural frequency of the muffler is collected through a 32-channel acoustic sensor array, and the suspected leakage points are located by comparing the theoretical modal analysis results; the detection sensitivity of the helium mass spectrometer reaches 5×10^-9 Pa·m 3 / s, the scanning probe moves along the preset spiral trajectory at a speed of 10 mm / s for detection; the judgment criterion is that the leakage rate of the whole device is less than 1×10^-7 Pa·m 3 / s, and at the same time, the structural integrity is verified through a 100 - 5000 Hz swept-frequency vibration test.

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