Method for improving service performance of welded joint, welding method and device

Abstract

The invention discloses a method for improving the service performance of a welded joint and a welding method and device. The method for improving the service performance of the welded joint comprises the steps that a welding track is obtained; carrying out temperature scanning on the welding point, obtaining a temperature field distribution diagram of a related molten pool and taking the molten pool as the center at the T moment, and determining a first response region with the temperature of 400-600 DEG C; determining a laser spot position A, a laser position state parameter and a laser parameter in the first response area; and the state of the laser is adjusted, and the laser spot position A is irradiated. According to the method, the partial melting area is remelted by using the following welding laser, and a thick low-melting-point precipitated phase on the surface layer of the partial melting area is melted and converted into a fine precipitated phase, so that the corrosion resistance of the partial melting area is improved; the high-temperature partial melting area with the temperature ranging from 400 DEG C to 600 DEG C is impacted through welding following laser, residual compressive stress is introduced, formation of liquefaction cracks in the partial melting area is restrained, and the fatigue performance of the partial melting area is improved.

Description

Technical Field

[0001] The present invention belongs to the field of welding technology, and in particular relates to a method for improving the service performance of a welded joint, a welding method and a device. Background Art

[0002] A welded joint refers to a joint in which two or more parts are connected by welding, including the weld zone, partial melting zone and heat-affected zone. The weld zone is composed of molten base material and filler metal. The partial melting zone is located at the junction of the weld zone and the heat-affected zone. The heat-affected zone is the area where the structure and properties are changed by the high temperature heating of the weld zone.

[0003] During the arc welding of aluminum alloys, liquefaction cracks and coarsening of low-melting-point precipitates can occur in the partially melted zone adjacent to the weld, which can seriously reduce the fatigue and corrosion resistance of the weld joint. Numerous studies have shown that the formation of liquefaction cracks in the partially melted zone can be effectively suppressed by using high-fluidity Al-Si welding wires or by adopting appropriate measures to convert the residual tensile stress at the weld toe into compressive stress. Among them, the method of suppressing liquefaction cracks with high-fluidity Al-Si welding wires increases the tendency of weld porosity and reduces weld strength. Although methods such as hammering, ultrasonication, and rolling can improve weld structure while regulating the stress distribution at the weld toe, these methods suffer from complex equipment, low flexibility, and low accessibility. Furthermore, these methods cannot address the problem of coarsening of low-melting-point precipitates in the partially melted zone.

[0004] Therefore, it is urgent to develop a method that can suppress cracks in the partial melting zone and improve the morphology of the low-melting-point precipitation phase, so as to achieve a synergistic improvement in the fatigue and corrosion properties of aluminum alloy arc welding joints. Summary of the Invention

[0005] The purpose of the present invention is to provide a method, a welding method and a device for improving the service performance of welded joints, which can achieve a synergistic improvement in the corrosion and fatigue performance of aluminum alloy welded joints.

[0006] In order to achieve the above object, a specific embodiment of the present invention provides the following technical solutions:

[0007] A method for improving the service performance of a welded joint, comprising:

[0008] Get welding trajectory;

[0009] Perform temperature scanning on the welding point, obtain the temperature field distribution diagram of the molten pool and the molten pool as the center at time T, and determine the first response area with a temperature of 400℃-600℃;

[0010] Determine the laser spot position A, laser position state parameters, and laser parameters in the first response area;

[0011] Adjust the laser state and irradiate the laser spot position A. Within the first response zone, the distribution of the laser spot position A can be continuous or discrete; it can be distributed on one side of the welding track or on both sides of the welding track. When distributed on both sides of the welding track, the lines connecting the geometric centers of each laser spot position A and the geometric centers of the molten pool can be symmetrically distributed on both sides of the welding track, such as when welding workpieces of the same material. It can also be asymmetrically distributed, such as when welding workpieces of different materials, with the lines connecting the geometric centers of the laser spot positions A and the molten pool closer to the welding track for parts more prone to liquefaction cracks. When the laser spot positions A on the same side are distributed as discrete points or islands, the overall geometric center is determined by the overall shape obtained by smoothly connecting the outermost edges.

[0012] In one or more embodiments of the present invention, the selection basis of the laser spot position A includes at least any one of the following: welding process type, composition of the material to be welded.

[0013] In one or more embodiments of the present invention, the laser position state parameters include at least any of the following: the position coordinates of the laser relative to the welding point, and the laser state parameters. The state parameters may include emission angle, motion speed, and movement path, etc., to ensure that the laser is in the proper operating state throughout the welding operation and achieves complete weld processing.

[0014] In one or more embodiments of the present invention, the laser parameters include at least any one of the following: modulation / pulse frequency, duty cycle, and peak power.

[0015] Another specific embodiment of the present invention provides a technical solution as follows:

[0016] The welding method for achieving the above-mentioned method of improving the service performance of the welded joint includes:

[0017] Welding the materials to be welded to form a molten weld pool at the welding position of the materials to be welded;

[0018] The material to be welded is aluminum alloy. During the welding process, a laser is used to irradiate the first response zone with a temperature of 400°C-600°C outside the welding molten pool, and the light spot formed by the laser irradiation moves along with the molten pool formed by the welding.

[0019] In one or more embodiments of the present invention, all or part of the first response area on one side and / or both sides of the welding pool is irradiated based on the welding track, and the irradiation is performed using one or more laser beams.

[0020] In one or more embodiments of the present invention, a laser is used to generate the laser light, wherein the modulation / pulse frequency of the laser light is 10 Hz-1000 Hz, the duty cycle is 50%-80%, and the peak power is 500 W-1000 W.

[0021] In one or more embodiments of the present invention, a non-contact thermometer is used to detect the temperature of the partially melted zone outside the welding pool.

[0022] In one or more embodiments of the present invention, arc welding is used to weld the materials to be welded. The arc welding is any one of TIG, MIG, and CMT.

[0023] Another specific embodiment of the present invention provides a technical solution as follows:

[0024] A device for improving the service performance of a welded joint, comprising:

[0025] Workbench, used to fix the materials to be welded;

[0026] Welding mechanism, for welding the materials to be welded;

[0027] The temperature detection mechanism detects the temperature of the partial melting zone outside the welding pool and determines the first response zone with a temperature of 400°C-600°C;

[0028] A laser device, providing laser light for irradiating a part or the entire first response area;

[0029] The laser action position feedback adjustment system adjusts the laser irradiation position of the partially melted area according to the temperature of the partially melted area detected by the temperature detection mechanism.

[0030] In one or more embodiments of the present invention, the laser is further provided with a spectrometer, which is used to split a single laser beam from the light source into multiple first laser beams to irradiate several selected laser spot positions A in the first response area respectively, wherein the number of laser spot positions A is not greater than the number of first laser beams.

[0031] In one or more embodiments of the present invention, the laser action position feedback adjustment system further includes a splitting distance adjustment device, and the splitting distance adjustment device is used to adjust the distance between the multiple first laser beams.

[0032] In one or more embodiments of the present invention, the laser action position feedback adjustment system also includes a controller, which selects the regional information of the laser spot position A in the first response area based on at least the composition information of the material to be welded, the welding process information, and the laser parameter information; and / or the controller determines the state parameters of the laser and controls the laser spot to move along with the molten pool based on at least the welding trajectory information, the initial position information of the laser, and the regional information of the laser spot position A; and / or the controller compares at least the real-time position information of the laser spot position A and / or the power density information of the irradiation interface with the fitting path and / or preset power formed by the preset welding trajectory information, and determines the current intervention state based on the comparison information.

[0033] Compared with the existing technology, the present invention uses welding pulses or modulated lasers to remelt the partially melted zone, melts the coarse low-melting-point precipitates on the surface of the partially melted zone and transforms them into fine precipitates, thereby improving the corrosion resistance of the partially melted zone; uses welding pulses or modulated lasers to impact the high-temperature partially melted zone with a temperature between 400°C and 600°C to introduce residual compressive stress, inhibit the formation of liquefaction cracks in the partially melted zone, and improve the fatigue performance of the partially melted zone. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0035] Figure 1 Schematic diagram of a device for improving the service performance of a welded joint according to an embodiment of the present invention;

[0036] Figure 2 Schematic diagram of the Fe phase contained in the corrosion pit in the partial melting zone (Figure (a)) and the depth of the corrosion pit (Figure (b)) in Comparative Example 1 of the present invention;

[0037] Figure 3 Schematic diagram of the Fe phase contained in the corrosion pit in the partial melting zone (Figure (a)) and the depth of the corrosion pit (Figure (b)) in Example 1 of the present invention. DETAILED DESCRIPTION

[0038] To help those skilled in the art better understand the technical solutions of the present disclosure, the following clearly and completely describes the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, not all of them. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present disclosure.

[0039] like Figure 1 As shown, a specific embodiment of the present invention provides a method for improving the service performance of a welded joint, comprising:

[0040] S1. Obtain welding trajectory.

[0041] Specifically, in this step, multiple camera systems may be used to capture images of weld seams of the materials to be welded for identification, thereby obtaining a fitting path for the welding trajectory of the materials to be welded.

[0042] S2. Scan the temperature of the welding point, obtain the temperature field distribution diagram of the molten pool and the molten pool as the center at time T, and determine the first response area with a temperature of 400°C-600°C.

[0043] Specifically, the temperature at the center of the welding pool is higher, and the temperature gradually decreases from the center of the pool to the outside. Through temperature scanning, such as using a thermometer such as an infrared camera to measure the temperature to determine the temperature field distribution, the control system analyzes the temperature field distribution state obtained by the thermometer to determine the position of the first response zone within the temperature gradient range of 400℃-600℃, that is, to confirm the area with high incidence of liquefaction cracks in the partial melting zone.

[0044] S3. Determine the laser spot position A, laser position state parameters, and laser parameters in the first response area.

[0045] Specifically, the selection basis of the laser spot position A includes at least any one of the following: welding process type, composition of the material to be welded; the laser position state parameters include at least any one of the following: position coordinates of the laser relative to the welding point, state parameters of the laser; laser parameters include at least any one of the following: modulation / pulse frequency, duty cycle, peak power.

[0046] In the present invention, the welding process type is arc welding, and the material to be welded is aluminum alloy. Different welding processes have different welding energy densities, which are reflected by the temperature at the center of the molten pool. At low energy density, the heat source energy concentration is low, and some areas outside the molten pool may be greatly affected. Different materials to be welded have different melting temperatures, and the temperature field distribution from the molten pool to the outside is also different. Therefore, the laser spot position A is selected based on the welding process type and the composition of the materials to be welded. At the same time, throughout the welding process, the trajectory of the center of the molten pool is basically consistent with the welding trajectory fitting path. Therefore, during the entire operation, the position of the laser and the laser spot position A can be programmatically controlled by a controller such as a PLC or a microcomputer, and the status of the laser can be evaluated by comparing it with the fitting path. Based on the comparative evaluation conclusion of the position and path, the intervention effect of the service performance can be preliminarily evaluated. For example, when the laser spot position A deviates significantly from the fitting path or is out of sync with the operation of the molten pool, it may indicate that the intervention has failed, thereby generating an alarm.

[0047] In combination with the position of the first response area and the laser spot position A, the laser position state parameters and laser parameters are determined so that the laser beam acts on the laser spot position A.

[0048] S4. Adjust the laser state and irradiate the laser spot position A.

[0049] Specifically, the position and angle of the laser are adjusted based on the laser spot position A so that the laser beam can irradiate the laser spot position A. This process is adjusted along with the welding point, such as the molten pool, throughout the welding process. This can be achieved by adjusting the laser position, transmission angle, and transmission power to form the required irradiation intensity on the interface of the laser spot position A.

[0050] Another specific embodiment of the present invention provides a welding method for improving the service performance of welded joints, including: welding the material to be welded, forming a welding pool at the welding point of the material to be welded; wherein, the material to be welded is an aluminum alloy, and during the welding process, a laser is used to irradiate a first response zone with a temperature of 400°C-600°C outside the welding pool, and the light spot formed by the laser irradiation moves along with the molten pool formed by the welding.

[0051] Specifically, the partially melted zone outside the welding molten pool forms a fusion zone after cooling. The fusion zone is the transition area from the weld zone to the heat-affected zone. Although the area is small, it has a greater impact on the performance of the weld joint. Coarse grains are likely to exist in the fusion zone, which can easily reduce the fatigue resistance and corrosion resistance of the weld joint. The present invention uses a laser to perform local remelting of the partially melted zone outside the welding molten pool. On the one hand, the coarse melting point precipitates on the surface of the partially melted zone are melted by local laser remelting, and the formation of coarse low-melting point precipitates is suppressed by the rapid cooling characteristics of the laser molten pool; on the other hand, the impact of the laser is used to introduce compressive stress in the melting zone to suppress the formation of liquefaction cracks, thereby achieving a synergistic improvement in the corrosion and fatigue properties of the weld joint. The fatigue and corrosion resistance of the weld joint obtained by the method of the present invention are improved by more than 20% compared to conventional arc welding joints.

[0052] The laser's action area is limited to a temperature range of 400°C-600°C. At high temperatures, the yield strength of aluminum alloy is almost zero. By using laser for impact forging in this temperature range, the forging force can exceed the yield strength of the aluminum alloy, causing it to undergo plastic deformation, thereby introducing compressive stress in the area and inhibiting the formation of liquefaction cracks.

[0053] The temperature range of the partial melting zone can be specifically selected from 400℃-600℃, 400℃-450℃, 400℃-500℃, 400℃-550℃, 450℃-600℃, 500℃-600℃, 550℃-600℃, and 450℃-550℃.

[0054] Furthermore, the welded material is one of 6XXX aluminum alloy, 2XXX aluminum alloy, and 7XXX aluminum alloy.

[0055] Specifically, the materials to be welded should be cleaned and dried before welding. Conventional mechanical methods should be used to remove the oxide scale from the surface of the materials to be welded, such as grinding with sandpaper, a grinding stone, or a metal brush. The surface should then be cleaned with acetone to remove surface oil and allowed to dry, to reduce the introduction of impurities that could affect welding performance.

[0056] Furthermore, based on the welding track, all or part of the first response area on one side and / or both sides of the welding pool are irradiated, and the irradiation is performed using one or more laser beams.

[0057] Specifically, different numbers of laser beams can be selected based on actual needs, so that the laser beam irradiation range can cover the temperature range of 400°C-600°C. For example, after the laser is emitted from the laser head, it is split into two laser beams after passing through a beam splitter, and the two laser beams act on the molten zones on both sides of the weld pool respectively.

[0058] Furthermore, the laser is a modulated laser or a pulsed laser. The laser is generated by a laser with a modulation / pulse frequency of 10 Hz to 1000 Hz, a duty cycle of 50% to 80%, and a peak power of 500W to 1000W.

[0059] Furthermore, a non-contact thermometer is used to detect the temperature of the partial melting zone outside the welding pool.

[0060] Specifically, the non-contact thermometer can be any one of an infrared thermometer, an infrared thermal imaging thermometer, and a fiber optic temperature sensor. The thermometer detects the temperature of the melting zone, and based on the feedback, the laser action position feedback adjustment system controls the splitting spacing adjustment device to adjust the laser action position, ensuring that the laser beam accurately acts on the melting zone with a temperature of 400°C-600°C.

[0061] Furthermore, the materials to be welded are welded by arc welding, and the arc welding can be any one of TIG, MIG, and CMT.

[0062] Another specific embodiment of the present invention provides a device for improving the service performance of welding joints, including: a workbench for fixing the material to be welded; a welding mechanism for welding the material to be welded; a temperature detection mechanism for detecting the temperature of the partial melting zone outside the welding pool and determining a first response zone with a temperature of 400°C-600°C; a laser for providing laser light for irradiating part or all of the first response zone; and a laser action position feedback adjustment system for adjusting the laser irradiation position of the partial melting zone according to the temperature of the partial melting zone detected by the temperature detection mechanism.

[0063] Specifically, the materials to be welded are placed on the workbench in the form of butt joints, overlap joints or corner joints and fixed with welding fixtures. When welding is performed by the welding mechanism, a temperature detection mechanism (infrared temperature camera) is used to detect the temperature of the partial melting zone on both sides of the welding pool. Based on the feedback results, the laser action position is adjusted through the laser action position feedback adjustment system, so that the laser irradiates the area within a specific temperature range (400℃-600℃), thereby achieving the purpose of improving the corrosion resistance and fatigue resistance of the melting zone.

[0064] Among them, the laser action position feedback adjustment system is a conventional device in this field. For example, the laser action position feedback adjustment system determines the laser action position through visual sensors, laser trackers, etc., and issues adjustment instructions based on the position of the partially melted area fed back by an infrared temperature measurement camera, and adjusts the laser action position by moving the laser or adjusting the laser angle.

[0065] Furthermore, the laser is also provided with a spectrometer, which is used to split the single laser beam of the light source into multiple first laser beams to irradiate several selected laser spot positions A in the first response area respectively, wherein the number of laser spot positions A is not greater than the number of first laser beams.

[0066] Furthermore, the laser action position feedback adjustment system further includes a splitting spacing adjustment device, which is used to adjust the spacing between the multiple first laser beams.

[0067] Specifically, such as Figure 1 As shown, the laser emitted by the laser head in the laser is divided into two laser beams by a spectrometer. The two laser beams act on the partial melting zones on both sides of the welding pool respectively. The laser action position feedback adjustment system issues adjustment instructions according to the temperature measured by the infrared temperature measuring camera, and controls the spectroscopic spacing adjustment device to adjust the spacing between the two laser beams. The spectroscopic spacing adjustment device is a conventional device in this field. For example, the laser angle can be adjusted by adjusting the reflection angle of the reflector in the laser, and the spacing between the two laser beams can be adjusted in combination with the spectrometer, so that the two laser beams act on the partial melting zones on both sides of the welding pool with a temperature between 400℃ and 600℃.

[0068] The present invention is further described in detail below with reference to specific embodiments.

[0069] Example 1

[0070] The welding method for improving the service performance of a welded joint in this embodiment includes the following steps:

[0071] Step (1): Select 6082-T6 aluminum alloy with a size of 100 mm × 80 mm × 3.0 mm, remove the oxide scale in the welding area by mechanical method, remove the surface oil with acetone and dry it for use;

[0072] Step (2): The CMT welding process is used to butt-weld the joints. The filler wire is ER5183 wire with a diameter of 1.2 mm. The wire feeding speed is 6.8 m / min, the welding speed is 0.6 m / min, the current is 115 A, and the voltage is 20 V.

[0073] Step (3): An infrared temperature camera is used to detect the temperature of the partially melted zones on both sides of the weld pool. Based on the temperature measurement feedback from the infrared camera, two laser beams are placed in the partially melted zones on both sides of the weld pool with a temperature between 400°C and 600°C. The selected laser beam is generated by an IPG6000 laser equipped with a spectrometer. It is a square waveform modulated laser with a modulation frequency of 100 Hz, a duty cycle of 80%, and a peak power of 800 W.

[0074] Step (4): After welding, evaluate the fatigue and corrosion properties of the welded joint.

[0075] Example 2

[0076] The welding method for improving the service performance of a welded joint in this embodiment includes the following steps:

[0077] Step (1): Select 7075-T6 aluminum alloy with a size of 100 mm × 80 mm × 3.0 mm, remove the oxide scale in the welding area by mechanical method, remove the surface oil with acetone and dry it for use;

[0078] Step (2): The CMT welding process is used to butt-weld the above joints, and the filler wire is ER5183 welding wire with a diameter of 1.2 mm; the wire feeding speed is 6.8 m / min, the welding speed is 0.6 m / min, the current is 115 A, and the voltage is 20 V;

[0079] Step (3): An infrared temperature camera is used to detect the temperature of the partially melted zone on both sides of the welding pool. According to the temperature measurement feedback results of the infrared camera, two laser beams are placed in the partially melted zone with a temperature between 400°C and 500°C. The selected laser beam is generated by an IPG6000 laser equipped with a spectrometer. It is a square waveform modulated laser with a modulation frequency of 1000 Hz, a duty cycle of 80%, and a peak power of 600 W.

[0080] Step (4): After welding, evaluate the fatigue and corrosion properties of the welded joint.

[0081] Example 3

[0082] The welding method for improving the service performance of a welded joint in this embodiment includes the following steps:

[0083] Step (1): Select 2219-T6 aluminum alloy with a size of 100 mm × 80 mm × 2.0 mm, remove the oxide scale in the welding area by mechanical method, remove the surface oil with acetone and dry it for use;

[0084] Step (2): The CMT welding process is used to butt-weld the joints, and the filler wire is ER2319 welding wire with a diameter of 1.2 mm; the wire feeding speed is 4.8 m / min, the welding speed is 0.7 m / min, the current is 115 A, and the voltage is 20 V;

[0085] Step (3): An infrared temperature camera is used to detect the temperature of the partially melted zone on both sides of the welding pool. According to the temperature measurement feedback results of the infrared camera, two laser beams are placed in the partially melted zone with a temperature between 500℃ and 600℃. The selected laser beam is generated by an IPG6000 laser equipped with a spectrometer. It is a square waveform modulated laser with a modulation frequency of 10 Hz, a duty cycle of 80%, a peak power of 1000 W, and a valley power of 0 W.

[0086] Step (4): After welding, evaluate the fatigue and corrosion properties of the welded joint.

[0087] Comparative Example 1

[0088] The welding method in this comparative example includes the following steps:

[0089] Step (1): Select 6082-T6 aluminum alloy with a size of 100 mm × 80 mm × 3.0 mm, remove the oxide scale in the welding area by mechanical method, remove the surface oil with acetone and dry it for use;

[0090] Step (2): The CMT welding process is used to butt-weld the joints. The filler wire is ER5183 wire with a diameter of 1.2 mm. The wire feeding speed is 6.8 m / min, the welding speed is 0.6 m / min, the current is 115 A, and the voltage is 20 V.

[0091] Step (3): After welding, the fatigue and corrosion properties of the welded joint are evaluated.

[0092] Comparative Example 2

[0093] The welding method in this comparative example includes the following steps:

[0094] Step (1): Select 7075-T6 aluminum alloy with a size of 100 mm × 80 mm × 3.0 mm, remove the oxide scale in the welding area by mechanical method, remove the surface oil with acetone and dry it for use;

[0095] Step (2): The CMT welding process is used to butt-weld the above joints, and the filler wire is ER5183 welding wire with a diameter of 1.2 mm; the wire feeding speed is 6.8 m / min, the welding speed is 0.6 m / min, the current is 115 A, and the voltage is 20 V;

[0096] Step (3): After welding, evaluate the fatigue and corrosion properties of the welded joint.

[0097] Comparative Example 3

[0098] The welding method in this comparative example includes the following steps:

[0099] Step (1): Select 2219-T6 aluminum alloy with a size of 100 mm × 80 mm × 2.0 mm, remove the oxide scale in the welding area by mechanical method, remove the surface oil with acetone and dry it for use;

[0100] Step (2): The CMT welding process is used to butt-weld the joints, and the filler wire is ER2319 welding wire with a diameter of 1.2 mm; the wire feeding speed is 4.8 m / min, the welding speed is 0.7 m / min, the current is 115 A, and the voltage is 20 V;

[0101] Step (3): After welding, evaluate the fatigue and corrosion properties of the welded joint.

[0102] Comparative Example 4

[0103] The welding method in this comparative example includes the following steps:

[0104] Step (1): Select 6082-T6 aluminum alloy with a size of 100 mm × 80 mm × 3.0 mm, remove the oxide scale in the welding area by mechanical method, remove the surface oil with acetone and dry it for use;

[0105] Step (2): The CMT welding process is used to butt-weld the joints. The filler wire is ER5183 wire with a diameter of 1.2 mm. The wire feeding speed is 6.8 m / min, the welding speed is 0.6 m / min, the current is 115 A, and the voltage is 20 V.

[0106] Step (3): An infrared temperature camera is used to detect the temperature of the partially melted zone on both sides of the welding pool. According to the temperature measurement feedback of the infrared camera, the two laser beams are placed in the partially melted zone with a temperature between 200°C and 300°C. The selected laser beam is generated by an IPG6000 laser equipped with a spectrometer. It is a square waveform modulated laser with a modulation frequency of 100 Hz, a duty cycle of 80%, and a peak power of 800 W.

[0107] Step (4): After welding, evaluate the fatigue and corrosion properties of the welded joint.

[0108] Comparative Example 5

[0109] The welding method in this comparative example includes the following steps:

[0110] Step (1): Select 6082-T6 aluminum alloy with a size of 100 mm × 80 mm × 3.0 mm, remove the oxide scale in the welding area by mechanical method, remove the surface oil with acetone and dry it for use;

[0111] Step (2): The CMT welding process is used to butt-weld the joints. The filler wire is ER5183 wire with a diameter of 1.2 mm. The wire feeding speed is 6.8 m / min, the welding speed is 0.6 m / min, the current is 115 A, and the voltage is 20 V.

[0112] Step (3): An infrared temperature camera is used to detect the temperature of the partially melted zone on both sides of the welding pool. According to the temperature measurement feedback of the infrared camera, the two laser beams are placed in the partially melted zone with a temperature between 300°C and 400°C. The selected laser beam is generated by an IPG6000 laser equipped with a spectrometer. It is a square waveform modulated laser with a modulation frequency of 100 Hz, a duty cycle of 80%, and a peak power of 800 W.

[0113] Step (4): After welding, evaluate the fatigue and corrosion properties of the welded joint.

[0114] The fatigue performance of the welded joints in each embodiment and each comparative example was tested, and the fatigue loading condition was pull / pull, R=0.1, and the number of fatigue cycles was 10 7 The specific results are shown in Table 1.

[0115] Table 1 High frequency of welded joints (N=10 7 ) Fatigue performance (R=0.1)

[0116]

[0117] As shown in Table 1, in Comparative Example 1, laser irradiation of the molten zone was not used during welding, and the high-cycle fatigue limit of the welded joint was 45 MPa. Although laser irradiation of the molten zone was used during welding in Comparative Examples 4 and 5, the high-cycle fatigue limits of the welded joints for the partial molten zone at temperatures between 200°C and 300°C and the partial molten zone at temperatures between 300°C and 400°C were not significantly different from those in Comparative Example 1, at 43 MPa and 47 MPa, respectively. The high-cycle fatigue limit of the welded joint in Example 1 reached 60 MPa. Under high stress conditions, the welded joints all fractured in the heat-affected zone, not at the weld toe. This indicates that laser irradiation of the molten zone requires irradiation within a specific temperature range to effectively improve the fatigue performance of the welded joint.

[0118] The welding materials used in Comparative Example 2 were 7075-T6 aluminum alloy, and those used in Comparative Example 3 were 2219-T6 aluminum alloy. Under high stress conditions, both the 7075-T6 and 2219-T6 aluminum alloy welded joints fractured at the weld toe, with high-cycle fatigue limits reaching 50 MPa and 48 MPa, respectively. In contrast, both the 7075-T6 aluminum alloy welded joint in Example 2 and the 2219-T6 aluminum alloy welded joint in Example 3 fractured in the heat-affected zone under high stress conditions, with high-cycle fatigue limits reaching 65 MPa and 60 MPa, respectively. These results demonstrate excellent fatigue performance and demonstrate that laser irradiation of the partially molten zones on both sides of the weld pool can effectively improve the fatigue performance of welded joints.

[0119] The welded joints in each embodiment and each comparative example were immersed in a 3.5% NaCl solution for 24 hours, and the depth of the corrosion pits on the cross section of the welded joints was measured to determine the corrosion resistance of the welded joints. The specific results are shown in Table 2.

[0120] Table 2 Depth of corrosion pits in the partially melted zone of welded joints

[0121]

[0122] After soaking in 3.5% NaCl solution for 24 hours, Figure 2 It can be seen that the partial melting zone in comparative example 1 is the deepest area of ​​the corrosion pit of the weld joint, with a corrosion depth of 50 μm. Further observation of the microstructure of the corrosion pit reveals the presence of coarse chain-like Fe-containing phases in the corrosion pit. The large potential difference between the Fe-containing phase and the α-Al matrix causes the adjacent α-Al matrix to be rapidly corroded, thereby significantly reducing the corrosion resistance of the weld joint. Figure 3 The depth of the corrosion pit of the weld joint in Example 1 is reduced to 20 μm. The reason is that in Example 1, laser is used to remelt the partial melting zone, and the coarse Fe-containing phase in the partial melting zone on the surface of the weld joint disappears, leaving only a small amount of fine circular Fe-containing phase. By changing the morphology of the Fe-containing phase, the contact area between the phase and the α-Al matrix is ​​greatly reduced, thereby greatly reducing the location of inducing corrosion, and improving the corrosion resistance of the partial melting zone of the weld joint.

[0123] Further comparing Comparative Example 2 and Comparative Example 3, the depth of the corrosion pit in the partial melting zone of the 7075-T6 aluminum alloy welded joint in Comparative Example 2 is 80 μm, and the depth of the corrosion pit in the partial melting zone of the 2219-T6 aluminum alloy welded joint in Comparative Example 3 is 70 μm, while the depth of the corrosion pit in Example 2 and Example 3 is reduced to 35 μm and 25 μm, indicating that selecting a temperature range within the range of 400°C-600°C for laser irradiation can also achieve excellent results in improving corrosion resistance.

[0124] It will be apparent to those skilled in the art that the present disclosure is not limited to the details of the exemplary embodiments described above, and that the present disclosure can be implemented in other specific forms without departing from the spirit or essential characteristics of the present disclosure. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present disclosure is defined by the appended claims rather than the foregoing description, and all variations that come within the meaning and range of equivalents of the claims are intended to be included in the present disclosure.

[0125] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for improving the service performance of a welded joint, characterized in that: include: Get welding trajectory; Perform temperature scanning on the welding point, obtain the temperature field distribution diagram of the molten pool and the molten pool as the center at time T, and determine the first response area with a temperature of 400℃-600℃; Determine the laser spot position A, laser position state parameters, and laser parameters in the first response area; Adjust the laser state and irradiate the laser spot position A.

2. The method for improving the service performance of a welded joint according to claim 1, characterized in that: The selection basis of the laser spot position A includes at least any one of the following: welding process type and composition of the material to be welded.

3. The method for improving the service performance of a welded joint according to claim 1, characterized in that: The laser position state parameters include at least any one of the following: the position coordinates of the laser relative to the welding point, and the state parameters of the laser.

4. The method for improving the service performance of a welded joint according to claim 1, characterized in that: The laser parameters include at least any one of the following: modulation / pulse frequency, duty cycle, and peak power.

5. A welding method according to any one of claims 1 to 4, characterized in that: include: Welding the materials to be welded to form a molten weld pool at the welding position of the materials to be welded; The material to be welded is aluminum alloy. During the welding process, a laser is used to irradiate the first response zone with a temperature of 400°C-600°C outside the welding molten pool, and the light spot formed by the laser irradiation moves along with the molten pool formed by the welding.

6. The welding method according to claim 5, characterized in that Based on the welding track, all or part of the first response area on one side and / or both sides of the welding pool are irradiated, and the irradiation is performed using one or more laser beams.

7. The welding method according to claim 5, characterized in that The laser is generated by a laser, wherein the modulation / pulse frequency of the laser is 10 Hz-1000 Hz, the duty cycle is 50%-80%, and the peak power is 500W-1000W.

8. The welding method according to claim 5, characterized in that A non-contact thermometer is used to detect the temperature of the partial melting zone outside the welding pool.

9. The welding method according to claim 5, characterized in that: The materials to be welded are welded by arc welding, and the arc welding can be any one of TIG, MIG, and CMT.

10. A device for improving the service performance of a welded joint, characterized in that: include: Workbench, used to fix the materials to be welded; Welding mechanism, for welding the materials to be welded; The temperature detection mechanism detects the temperature of the partial melting zone outside the welding pool and determines the first response zone with a temperature of 400°C-600°C; A laser device, providing laser light for irradiating a part or the entire first response area; The laser action position feedback adjustment system adjusts the laser irradiation position of the partially melted area according to the temperature of the partially melted area detected by the temperature detection mechanism.

11. The device for improving the service performance of a welded joint according to claim 10, characterized in that: The laser is also provided with a spectrometer, which is used to split a single laser beam from the light source into multiple first laser beams to irradiate several selected laser spot positions A in the first response area respectively, wherein the number of laser spot positions A is not greater than the number of first laser beams.

12. The device for improving the service performance of a welded joint according to claim 11, characterized in that: The laser action position feedback adjustment system further includes a light splitting spacing adjustment device, which is used to adjust the spacing between the multiple first laser beams.

13. The device for improving the service performance of a welded joint according to any one of claims 10 to 12, characterized in that: The laser action position feedback adjustment system also includes a controller, The controller selects regional information of the laser spot position A in the first response area based on at least composition information of the material to be welded, welding process information, and laser parameter information; and / or The controller determines the state parameters of the laser and controls the laser spot to move along with the molten pool based on at least the welding trajectory information, the initial position information of the laser and the area information of the laser spot position A; and / or The controller at least compares the real-time position information of the laser spot position A and / or the power density information of the irradiation interface with the fitting path and / or preset power formed by the preset welding trajectory information, and determines the current intervention state based on the comparison information.

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