Automatic electric arc welding device and method for steel structure plate processing

Abstract

The application relates to the technical field of welding, and discloses an automatic electric arc welding device and method for steel structure plate processing, and aims to solve the problem that the strength and toughness of a weld are reduced, thereby affecting the welding quality of a steel structure plate. The device is characterized in that a transducer, a variable amplitude rod and an impact block are arranged, the impact block is immediately in contact with the weld, at this time, the weld is just solidified, but the temperature is still higher than the recrystallization temperature, the transducer transmits high-frequency vibration to the impact block through the variable amplitude rod, the impact block with high-frequency vibration applies ultrasonic micro forging to the weld, the high-frequency dynamic impact of the ultrasonic micro forging first causes the surface layer of the weld and a transition zone to produce uniform plastic predeformation, then high dislocation density is introduced into the surface layer of the weld, a large number of dynamic recrystallization nucleation cores are provided, the surface layer micro-porosity of the weld of the workpiece is compacted, the compactness is improved, and the welding quality of the workpiece is improved.

Description

Technical Field

[0001] This application relates to the field of welding technology, and in particular to an automatic arc welding device and method for processing steel structure plates. Background Technology

[0002] Steel structure panels are widely used in many fields such as construction, bridges, ships, pressure vessels and marine engineering due to their excellent load-bearing capacity and good processing performance. As an indispensable connection method in the manufacturing of steel structure panels, the welding quality of electric arc welding equipment directly determines the service safety and life of steel structure components. With the development of engineering structures towards larger size and higher parameters, more stringent requirements are placed on the mechanical properties and microstructure of welded joints of steel structure panels. In particular, the integrity and density of the weld area have become key factors restricting the overall structural reliability.

[0003] In some existing arc welding equipment, the metal at the weld joint of two steel structural plates undergoes a rapid heating, melting, solidification, and cooling thermal cycle during operation. This process typically results in the formation of coarse columnar or dendritic crystal structures in the weld zone. These coarse dendritic structures not only reduce the strength and toughness of the weld but also become weak points for crack initiation and propagation, thus severely affecting the load-bearing capacity and fatigue life of the welded joint of the steel structural plate. At the same time, the residual tensile stress caused by the welding thermal cycle further deteriorates the stress state in the weld area, increasing the risk of stress corrosion cracking and delayed fracture, thereby affecting the welding quality of the steel structural plate. Summary of the Invention

[0004] This application proposes an automatic arc welding device and method for processing steel structure panels, which has the advantages of refining dendrite structure and offsetting residual tensile stress in weld, thereby solving the problem that the strength and toughness of the weld are reduced, resulting in the welding quality of steel structure panels being affected.

[0005] To achieve the above objectives, this application adopts the following technical solution: an automatic arc welding device for processing steel structure plates, comprising: a worktable, wherein symmetrical grooves are provided on the upper surface of the worktable, and clamping plates are slidably installed in the grooves; workpieces, which are steel structure plates, are symmetrically placed on the upper surface of the worktable between the two clamping plates; a screw is rotatably installed inside the worktable, and the screw is connected to the clamping plates in a transmission manner; a mounting seat is provided directly above the weld seam between the two workpieces, the upper end of the mounting seat is fixedly connected to an external robotic arm, and a welding rod is fixedly installed in the middle of the lower side of the mounting seat. The welding torch includes a nozzle, a conductive tip, and a welding wire. The nozzle is fixedly installed in the middle position of the lower side of the mounting base. A protective gas delivery pipe on an external robotic arm passes through the mounting base and communicates with the nozzle. A conductive tip is fixedly installed in the middle position inside the nozzle. A wire feeding mechanism on the external robotic arm passes the welding wire through the mounting base and extends into the inner side of the conductive tip. A transducer is provided at the rear position of the lower side of the mounting base. An amplitude transformer is fixedly installed at the lower end of the transducer. An impact block is fixedly installed at the lower end of the amplitude transformer. The lower side of the impact block is a concave arc surface, and the concave arc surface of the impact block corresponds to the weld between the workpieces.

[0006] Furthermore, a mounting rod is provided on the lower side of the mounting base and at the rear side of the transducer. A rolling roller is rotatably mounted on the lower end of the mounting rod. The outer circumferential surface of the rolling roller is a concave arc surface, and the concave arc surface of the rolling roller corresponds to the weld between the workpieces.

[0007] Furthermore, a lifting slide plate is provided below the mounting base and outside the welding torch. Insert rods are fixedly installed on both sides of the upper side of the lifting slide plate. The upper end of the insert rod is slidably inserted into the interior of the mounting base. A spring is sleeved on the outside of the welding torch. The upper end of the spring is fixedly connected to the lower side of the mounting base, and the lower end of the spring is fixedly connected to the upper side of the lifting slide plate. The transducer and the mounting rod are both fixedly installed on the lower surface of the lifting slide plate.

[0008] Furthermore, a pressure plate is fixedly installed on the lower side of the lifting slide plate. The lower surface of the pressure plate is an arc surface. The lower surface of the pressure plate contacts symmetrical workpieces. The pressure plate and the mounting rod are arranged in a symmetrical front-to-back position with the welding gun as the center.

[0009] Furthermore, two symmetrical cantilever links are horizontally arranged between the pressure plate and the luffing rod. One end of each cantilever link is fixedly connected to the side of the pressure plate facing the welding gun, and the other end of each cantilever link is fixedly connected to the antinode of the luffing rod.

[0010] Furthermore, isolation pads are provided between the upper end of the transducer and the lifting slide plate, and between the upper side of the pressure plate and the lifting slide plate. The isolation pads are made of silicone rubber.

[0011] Furthermore, the concave arc surface of the impact block is provided with microgrooves, the microgrooves are in the shape of an "eight", and the narrow end of the microgrooves faces the welding torch.

[0012] Furthermore, both the rolling roller and the cantilever connecting rod are made of air-cooled hardening hot work die steel, and a flow guide is provided at the lower end of the nozzle facing the impact block.

[0013] A method for processing steel structure panels using automated arc welding equipment includes the following steps: Step 1: First, place the two workpieces on the side of the workbench and between the two clamping plates. Then, rotate the screw to bring the clamping plates closer together, thereby clamping the two workpieces and making the mating surfaces of the two workpieces in close contact. Step two: The external robotic arm drives the mounting base and the lifting slide plate to move down synchronously. When the roller contacts the workpiece, the mounting base continues to move down. At this time, the lifting slide plate is limited by the roller contacting the workpiece and cannot move down further. This causes the mounting base and the lifting slide plate to compress the spring together. Then, the external robotic arm drives the mounting base to move along the gap between the contact surfaces of the two workpieces. At the same time, the welding gun works and the end of the welding wire briefly contacts the workpiece. During this process, the contact nozzle is energized. When the welding wire is retracted, a strong electric arc is generated between the welding wire and the workpiece, which instantly melts the welding wire and the base metal of the workpiece and forms a molten pool on the workpiece. At the same time, the nozzle sprays protective gas around the molten pool, so that the protective gas forms a protective gas shield around the molten pool and the electric arc, thereby isolating oxygen, nitrogen and other gases in the air. Step 3: The external robotic arm drives the mounting base and welding torch forward, thereby melting the corresponding positions of the workpiece in sequence. As the welding torch leaves, the part of the workpiece that was originally melted solidifies into a weld. At this time, the running transducer transmits high-frequency vibration to the impact block through the amplitude transformer. The high-frequency vibrating impact block contacts the weld and applies ultrasonic micro-forging to the contacted weld. Step four: The aforementioned amplitude transformer transmits high-frequency vibration to the pressure plate simultaneously through the cantilever connecting rod, causing the pressure plate to transmit ultrasonic energy into the molten pool through the contacting workpiece, thus causing the bubbles in the molten pool to rise. Step 5: The impact block is moved away by the forward mounting seat. At this time, the rolling roller contacts the weld and applies rolling pressure to the weld. Step six: After the workpiece is welded, the welding torch stops working, the external robotic arm moves the mounting base upward to reset, so that the spring drives the lifting slide plate to reset. Then, the screw is reversed to loosen the clamping plate from the workpiece, and finally the welded workpiece is removed.

[0014] This application has the following beneficial effects: This application provides an automatic arc welding device for processing steel structure plates. Through the arrangement of a transducer, an amplitude transformer, and an impact block, the impact block moves with the welding torch as the welding torch moves along with the workpiece. After the welding torch finishes welding a certain position on the workpiece, the impact block immediately contacts that weld. Since the weld at that position has just solidified, but its temperature is still higher than the recrystallization temperature, and the transducer transmits high-frequency vibrations to the impact block through the amplitude transformer, the high-frequency vibrating impact block applies ultrasonic micro-forging to the weld. The high-frequency dynamic impact of the ultrasonic micro-forging first causes uniform plastic pre-deformation in the weld and transition zone surface, then introduces a high dislocation density into the weld surface, providing a large number of dynamic recrystallization nuclei. This causes the micro-porosity of the weld surface to be compacted, increasing density and thus improving the welding quality of the workpiece. Simultaneously, the micro-forging offsets the tensile stress on the weld surface through dynamic plastic deformation, further improving the welding quality of the workpiece.

[0015] With the installation rod and roller set up, after the impact block contacts the weld, the roller immediately presses over the weld. Since the weld has undergone ultrasonic micro-forging, the plastic deformation is more easily transmitted to the subsurface layer when the roller applies static pressure, which increases the compaction depth of the roller and closes the deeper micro-shrinkage porosity, further improving the density of the workpiece and thus improving the welding quality of the workpiece. At the same time, the roller continues to apply steady-state plastic deformation, further driving the recrystallization to proceed fully, ultimately making the surface grains of the weld finer and more uniform, thereby improving the surface hardness and strength of the weld and improving the welding quality of the workpiece. Attached Figure Description

[0016] The accompanying drawings, which form part of this specification, illustrate embodiments disclosed in this application and, together with the specification, serve to explain the principles disclosed in this application.

[0017] This application can be more clearly understood with reference to the accompanying drawings and the following detailed description, wherein: Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the mounting structure on the lower side of the mounting base of the present invention; Figure 3 This is a schematic diagram of the welding torch structure of the present invention; Figure 4 This is a schematic diagram of the structure provided on the upper surface of the lifting slide plate of the present invention; Figure 5 This is a schematic diagram showing the position of the cantilever linkage in this invention; Figure 6 This is a schematic diagram showing the connection state between the pressure plate and the amplitude transformer of the present invention; Figure 7 This is a schematic diagram of the rolling roller of the present invention; Figure 8This is a schematic diagram showing the connection state of the transducer, amplitude rod, and impact block of the present invention; Figure 9 This is a schematic diagram showing the microgroove opening state of the present invention.

[0018] In the diagram: 1. Workbench; 2. Slide groove; 3. Clamping plate; 4. Workpiece; 5. Screw; 6. Mounting base; 7. Welding torch; 70. Nozzle; 71. Conductive nozzle; 72. Welding wire; 8. Transducer; 9. Amplitude rod; 10. Impact block; 11. Mounting rod; 12. Roller roller; 13. Lifting slide plate; 14. Insert rod; 15. Spring; 16. Pressure plate; 17. Cantilever connecting rod; 18. Isolation pad; 19. Microgroove; 20. Flow guide. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0020] Example 1: Please refer to Figures 1-9 An automatic arc welding device for processing steel structure plates includes a worktable 1. The upper surface of the worktable 1 has symmetrically symmetrically arranged grooves 2. Clamping plates 3 are slidably installed within the grooves 2. Workpieces 4, which are steel structure plates, are symmetrically placed on the upper surface of the worktable 1 between the two clamping plates 3. A screw 5 is rotatably installed inside the worktable 1, forming a transmission connection with the clamping plates 3. A mounting base 6 is positioned directly above the weld seam between the two workpieces 4. The upper end of the mounting base 6 is fixedly connected to an external robotic arm. A welding torch 7 is fixedly installed in the middle of the lower side of the mounting base 6. The welding torch 7 includes a nozzle 70, a conductive tip 71, and a welding wire 72. The nozzle 70 is fixed... The protective gas delivery pipe on the external robotic arm passes through the mounting base 6 and is connected to the nozzle 70. A conductive nozzle 71 is fixedly installed in the middle of the lower side of the mounting base 6. The wire feeding mechanism on the external robotic arm passes the welding wire 72 through the mounting base 6 and extends into the inner side of the conductive nozzle 71. A transducer 8 is set at the rear side of the lower side of the mounting base 6 (the rear side is the direction in which the external robotic arm drives the mounting base 6 to move backward). An amplitude transformer 9 is fixedly installed at the lower end of the transducer 8. An impact block 10 is fixedly installed at the lower end of the amplitude transformer 9. The lower side of the impact block 10 is a concave arc surface, and the concave arc surface of the impact block 10 corresponds to the weld between the workpieces 4.

[0021] In use, first place two workpieces 4 on the side of the workbench 1 and between the two clamping plates 3. Then, rotate the screw 5 to bring the clamping plates 3 closer together, thereby clamping the two workpieces 4 and making the mating surfaces of the two workpieces 4 in close contact. Then, the external robotic arm drives the mounting base 6 to move along the gap between the contact surfaces of the two workpieces 4. At the same time, the welding torch 7 works and the end of the welding wire 72 briefly contacts the workpiece 4. During this process, the conductive nozzle 71 is energized. When the welding wire 72 is retracted, a strong electric arc is generated between the welding wire 72 and the workpiece 4, which instantly melts the metal of the welding wire 72 and the workpiece 4, forming a liquid metal pool (i.e., "molten pool") on the workpiece 4. At the same time, the nozzle 70 sprays protective gas around the molten pool, so that the protective gas forms a protective gas shield around the molten pool and the electric arc, thereby isolating oxygen, nitrogen and other gases in the air and preventing them from causing harmful effects such as oxidation and nitriding on the high-temperature liquid metal. Subsequently, the external robotic arm drives the mounting base 6 and welding torch 7 forward, thereby melting the corresponding positions of the workpiece 4 in sequence. As the welding torch 7 leaves, the part of the workpiece 4 that was originally melted solidifies into a weld. At this time, the transducer 8 operates and transmits high-frequency vibration to the impact block 10 through the amplitude transformer 9. When the high-frequency vibrating impact block 10 contacts the weld, since the weld at this position has just solidified, but its temperature is still higher than the recrystallization temperature, the high-frequency vibrating impact block 10 applies ultrasonic micro-forging to the contacted weld. The high-frequency dynamic impact of ultrasonic micro-forging first causes uniform plastic pre-deformation in the weld and transition zone surface, and then introduces a high dislocation density in the weld surface, providing a large number of dynamic recrystallization nuclei, which promotes the compaction of the micro-porosity of the weld surface of the workpiece 4, increases the density, and thus improves the welding quality of the workpiece 4. At the same time, the above-mentioned micro-forging offsets the tensile stress in the weld surface through dynamic plastic deformation, further improving the welding quality of the workpiece 4. Specifically, after the weld metal has just solidified, the surface temperature is still above the recrystallization temperature. At this time, the material is in a thermoplastic state with low deformation resistance and good plastic fluidity. The high-frequency impact block 10 applies dynamic compressive stress to the weld surface, so that the surface metal of the weld and heat-affected zone produces uniform plastic pre-deformation under low flow stress, which will not cause local cracking or peeling. Specifically, during ultrasonic micro-forging, high-frequency alternating stress causes the dislocation density inside the surface metal of the weld to increase rapidly, forming high-density dislocation cells and subgrain boundaries. Since the surface temperature of the weld is higher than the recrystallization temperature, dislocations undergo climb, slip, and rearrangement under thermal activation. A large number of subgrain boundaries continuously absorb dislocations, gradually forming large-angle grain boundaries, which become the nucleation core for dynamic recrystallization. Therefore, dynamic recrystallization occurs on the surface of the weld under micro-forging, and the original coarse dendritic structure is refined to form fine equiaxed crystals, thereby reducing the grain size of the surface metal and improving the surface strength and toughness of the weld. Specifically, when the weld has just solidified, its surface and near-surface layers often have micro-porosity and micropores formed by solidification shrinkage and gas escape. The high-frequency dynamic impact of ultrasonic micro-forging causes the surface metal of the weld, which is in a thermoplastic state, to produce directional plastic flow. The metal is forced to fill the micro-porosity and micropores, so that the porosity is closed, the pores are compacted, and the density of the weld surface layer is increased. Specifically, during the weld cooling process, due to the constraints of solidification shrinkage and thermal shrinkage by the workpiece 4, residual tensile stress is usually generated on the surface of the weld. Ultrasonic micro-forging introduces high-frequency dynamic compressive plastic deformation on the surface of the weld, causing the surface metal to have a tendency to plastic elongate. After cooling, this plastic elongation is suppressed by the surrounding elastic constraints, forming residual compressive stress on the surface of the weld. This residual compressive stress can effectively offset the residual tensile stress of welding, reduce the tendency of cold crack initiation, and improve the fatigue strength and stress corrosion resistance of the welded joint. After the workpiece 4 is welded, the welding torch 7 stops working, the external robotic arm moves the mounting base 6 upward to reset, then reverses the screw 5 to loosen the clamping plate 3 from the workpiece 4, and finally removes the welded workpiece 4.

[0022] Please see Figures 1-9 A mounting rod 11 is provided on the lower side of the mounting base 6 and at the rear side of the transducer 8. A rolling roller 12 is rotatably mounted on the lower end of the mounting rod 11. The outer circumferential surface of the rolling roller 12 is a concave arc surface, and the concave arc surface of the rolling roller 12 corresponds to the weld between the workpieces 4.

[0023] During the process of the welding torch 7 advancing and welding the workpiece 4, after the impact block 10 contacts the newly solidified weld, the impact block 10 is carried away by the forward-moving mounting seat 6. At this time, the rolling roller 12 contacts the weld and applies rolling pressure to it. Since the weld has undergone ultrasonic micro-forging, when the rolling roller 12 applies static pressure, the plastic deformation is more easily transmitted to the subsurface layer, which increases the compaction depth of the rolling roller 12, thereby closing the deeper micro-shrinkage porosity, further improving the density of the workpiece, and thus improving the welding quality of the workpiece. At the same time, the rolling continues to apply steady-state plastic deformation, further driving the recrystallization to proceed fully, ultimately making the surface grains of the weld further finer and more uniform, thereby improving the surface hardness and strength of the weld and improving the welding quality of the workpiece. Specifically, after the high-frequency vibration of the impact block 10 pre-treats the weld, the uniformity, density and plasticity of the weld surface are improved, and the tendency of strain localization caused by local stress concentration and defects is reduced. Therefore, when the rolling roller 12 applies static pressure, the plastic deformation is no longer hindered by surface defects or coarse structure, but is stably transmitted to the subsurface layer by layer along the depth direction, which increases the effective compaction depth of the rolling roller 12. Specifically, ultrasonic micro-forging causes plastic deformation in the weld surface layer in advance and introduces high dislocation density and fine grain structure. Since fine grain material has more uniform deformation capacity and lower flow stress gradient in thermoplastic state, the static pressure applied by the rolling roller 12 can overcome the difference in deformation resistance between the surface layer and the subsurface layer, so that plastic strain can propagate to deeper layers, close deeper micro shrinkage porosity and solidification micropores, and further improve the overall density of the weld. Specifically, the weld is still in a thermoplastic state above the recrystallization temperature during rolling. The steady-state compressive plastic deformation applied by the rolling roller 12 causes the subgrain boundaries and high-density dislocations formed by ultrasonic micro-forging to move and rearrange further, providing additional deformation energy storage and nucleation sites for dynamic recrystallization. Under the continuous steady-state strain, the recrystallization process is more complete, and the fine grains formed by the original micro-forging are further homogenized and equiaxed, and the grain size is further reduced. Specifically, after the combined treatment of ultrasonic micro-forging and rolling, the grains of the surface and subsurface layers of the weld are further refined, the grain boundary area is increased, and the ability to hinder dislocation movement is enhanced, thereby improving the hardness and strength of the weld surface. At the same time, the closure of the deep micro-porosity increases the material density, reduces internal defects, further improves the load-bearing capacity and fatigue performance of the welded joint, and improves the welding quality of workpiece 4.

[0024] Example 2: Please refer to Figures 1-9 A lifting slide plate 13 is provided below the mounting base 6 and outside the welding torch 7. Insert rods 14 are fixedly installed on both sides of the upper side of the lifting slide plate 13. The upper end of the insert rod 14 is slidably inserted into the interior of the mounting base 6. A spring 15 is sleeved on the outside of the welding torch 7. The upper end of the spring 15 is fixedly connected to the lower side of the mounting base 6, and the lower end of the spring 15 is fixedly connected to the upper side of the lifting slide plate 13. The transducer 8 and the mounting rod 11 are both fixedly installed on the lower surface of the lifting slide plate 13.

[0025] Before welding with the welding torch 7, the external robotic arm drives the mounting base 6 and the lifting slide plate 13 to move down synchronously. When the rolling roller 12 contacts the workpiece 4, the mounting base 6 continues to move down. At this time, the lifting slide plate 13 is restricted by the rolling roller 12, so that the mounting base 6 and the lifting slide plate 13 jointly compress the spring 15. Afterwards, due to the undulation of the solidified weld reinforcement along the welding direction, the lifting slide plate 13 and the spring 15 are set so that the lifting slide plate 13 can drive the insert rod 14 to slide up and down under the action of the spring 15, and drive the impact block 10 and the rolling roller 12 to automatically rise and fall with the weld surface contour. The compression of the spring 15 is adjusted with the change of surface height, so that the impact block 10 and the rolling roller 12 always act on the surface of the weld or workpiece 4 with a stable normal pressure, avoiding excessive local pressure or separation of the impact block 10 and the rolling roller 12 due to rigid connection, thereby ensuring the continuity and uniformity of ultrasonic micro-forging and rolling compaction.

[0026] Please see Figures 1-9 A pressure plate 16 is fixedly installed on the lower side of the lifting slide plate 13. The lower surface of the pressure plate 16 is an arc surface. The lower surface of the pressure plate 16 contacts the symmetrical workpiece 4. The pressure plate 16 and the mounting rod 11 are arranged in a symmetrical position with the welding gun 7 as the center.

[0027] During the above welding process, the pressure plate 16 is always pressed against the area to be welded in front of the welding gun 7, thereby applying a downward clamping force to the two workpieces 4. This clamping force makes the mating edges of the two workpieces 4 fit tightly together, reduces the assembly gap, prevents the two workpieces 4 from being misaligned due to thermal expansion or the movement of the robotic arm, ensures uniform weld formation, and improves welding quality. Meanwhile, since the pressure plate 16 is located in front of the welding gun 7 and is symmetrically arranged with the roller 12 behind it, both are installed on the lifting slide plate 13. Together with the spring 15, they form a symmetrical elastic clamping system. During welding, the front pressure plate 16 applies a restraining force to the unwelded part of the workpiece 4, and the rear roller 12 applies a pressing force to the just solidified weld. The front and rear forces are balanced, preventing the lifting slide plate 13 from tilting back and forth, ensuring the relative position stability of the impact block 10, the roller 12 and the weld, and improving the consistency of the ultrasonic micro-forging and rolling compaction effects.

[0028] Example 3: Please refer to Figures 1-9 Two symmetrical cantilever links 17 are horizontally arranged between the pressure plate 16 and the amplitude rod 9. One end of the cantilever link 17 is fixedly connected to the side of the pressure plate 16 facing the welding gun 7, and the other end of the cantilever link 17 is fixedly connected to the antinode of the amplitude rod 9.

[0029] When the amplitude transformer 9 is working, it is in a longitudinal resonance state, and the vibration displacement is the largest at its antinode. Therefore, the cantilever connecting rod 17 can efficiently extract ultrasonic vibration energy at this point and transmit it to the pressure plate 16, so that the pressure plate 16 generates high-frequency micro-amplitude vibration during the welding process. Since the pressure plate 16 presses on the surface of the part to be welded of the workpiece 4 and forms a sliding contact with the workpiece 4, the above vibration forms an ultrasonic friction reduction effect at the contact interface between the pressure plate 16 and the workpiece 4, reducing the sliding friction force. This allows the pressure plate 16 to slide more smoothly over the surface of the workpiece 4 when it moves forward with the mounting base 6, avoiding adhesion, scratches or local jamming. At the same time, it makes the clamping force distribution more uniform, ensuring the continuity and stability of the pre-welding restraint. Meanwhile, since the pressure plate 16 is located in front of the welding torch 7, its vibration is directly transmitted to the unwelded part of the workpiece 4 through the contact surface. Since this part of the workpiece 4 is solid and directly connected to the front edge of the molten pool, the ultrasonic energy transmitted to the pressure plate 16 can propagate in the positive direction along the part of the workpiece 4 to be welded to the front edge area of ​​the molten pool. At the front edge of the molten pool, an acoustic impedance transition zone is formed between the solid workpiece 4 and the liquid metal. Some ultrasonic energy can penetrate into the liquid metal, generating an acoustic flow stirring effect, enhancing the convection of the liquid metal, promoting the upward escape of bubbles in the molten pool, reducing weld porosity, refining the solidification structure, and improving the internal quality of the weld. In addition, the two cantilever connecting rods 17 are symmetrically arranged on both sides of the pressure plate 16, so that the vibration transmitted from the amplitude rod 9 to the pressure plate 16 cancels each other in the horizontal direction, avoiding lateral swaying or off-center loading, ensuring that the pressure plate 16 only generates vibration components perpendicular to the surface of the workpiece 4, improving the ultrasonic energy transmission efficiency and service life. At the same time, the cantilever connecting rods 17 are connected to the antinode of the amplitude rod 9, which has little impact on the resonant mode of the amplitude rod 9 and will not significantly reduce the micro-forging amplitude of the impact block 10.

[0030] Please see Figures 1-9 An isolation pad 18 is provided between the upper end of the transducer 8 and the lifting slide plate 13, and between the upper side of the pressure plate 16 and the lifting slide plate 13. The isolation pad 18 is made of a high-damping elastic material (such as silicone rubber).

[0031] If the transducer 8 is rigidly connected to the lifting slide plate 13, the ultrasonic vibration will leak a large amount of energy to the lifting slide plate 13 along the connection interface, causing energy dispersion and loss. However, the high damping characteristics of the isolation pad 18 make it exhibit a large dynamic stiffness and loss factor at high frequencies, which can effectively absorb and attenuate the vibration components transmitted to the lifting slide plate 13, so that most of the ultrasonic energy is retained in the working path of the amplitude transformer 9, the impact block 10, and the pressure plate 16, thereby improving the efficiency of ultrasonic micro-forging and ultrasonic-assisted pressing. Although the isolation pad 18 acts as a vibration isolation element at ultrasonic frequencies, it still has sufficient stiffness under static or quasi-static loading to transmit the preload applied by the spring 15, so that the lifting slide plate 13 maintains a constant normal clamping force on the pressure plate 16 and the transducer 8. Therefore, the contact pressure between the impact block 10 and the weld, and between the pressure plate 16 and the workpiece 4, will not be significantly reduced due to the presence of the isolation pad 18, thus ensuring the stable contact conditions required for ultrasonic micro-forging and rolling compaction. The selected silicone rubber has good temperature resistance and anti-aging properties. Under the condition of continuous heat radiation during welding, it can still maintain elasticity and damping characteristics, and is not easy to harden, crack or permanently deform, ensuring that the isolation pad 18 maintains a stable vibration isolation and protection effect during long-term use.

[0032] Please see Figures 1-9The impact block 10 has a concave arc surface with a microgroove 19. The microgroove 19 has a figure-eight structure and the narrow end of the microgroove 19 faces the welding gun 7.

[0033] When the weld has just solidified, the surface often has slag, oxides and a small amount of incompletely floating bubbles left behind. The micro-groove 19 is V-shaped, with the narrow end located on the front side (close to the welding torch 7) and the wide end located on the rear side. When the impact block 10 slides forward, the weld surface moves backward relative to the impact block 10. The surface material entering the micro-groove 19 flows from the narrow end to the wide end under the guidance of the groove, that is, it is discharged directionally from the center of the weld to both sides of the weld. This directional slag discharge can effectively prevent slag and oxides from accumulating in the center of the weld and prevent the subsequent rolling roller 12 from pressing these impurities back into the weld, thereby improving the purity and density of the weld. The edges of the microgrooves 19 form dense micro-plow blades under ultrasonic high-frequency vibration. When the impact block 10 slides, the figure-eight microgrooves 19 exert a micro-plowing effect on the surface metal of the weld from the center to both sides, causing the surface metal to produce directional plastic flow. This directional flow not only helps to break up coarse dendrites and refine grains, but also pushes the surface metal to fill micro-porosity and micropores, close solidification defects, and improve the density of the weld surface. Compared with the planar impact block 10 without microgrooves 19, the figure-eight microgrooves 19 make the plastic flow have a clear directionality, and the material densification effect is more uniform. After the figure-eight microgrooves 19 discharge slag and oxides to both sides of the weld, the rolling rollers 12 that follow come into contact with the cleaned and micro-forged weld surface. The rolling compaction process is less prone to slag adhesion, the compaction resistance is reduced, and the compaction depth is increased.

[0034] Please see Figures 1-9 Both the rolling roller 12 and the cantilever connecting rod 17 are made of high elastic modulus tool steel (such as air-hardening hot work die steel 4Cr5MoSiV1 (H13)). A flow guide shroud 20 is connected to the lower end of the nozzle 70 and the position facing the impact block 10.

[0035] The rolling roller 12 directly contacts the weld surface that has just solidified and whose temperature is still higher than the recrystallization temperature during operation. It is subjected to high temperature, high pressure and repeated thermal cycling. The H13 material has excellent high temperature strength and resistance to tempering softening. It can still maintain high hardness and yield strength below 600℃, ensuring that the rolling roller 12 will not undergo plastic deformation or softening when rolling on the high temperature weld surface, maintaining the accuracy of the concave arc profile of the roller surface, and ensuring effective compaction of the weld reinforcement. Meanwhile, H13 has good thermal fatigue resistance and can withstand the cyclic thermal stress of repeated contact between the rolling roller 12 and the high-temperature weld and then cooling. It is not easy to generate thermal fatigue cracks and extend the service life of the rolling roller 12. Its high elastic modulus makes the rolling roller 12 deform less under the action of rolling force, which is conducive to maintaining a stable contact stress distribution and improving the uniformity of compaction depth. In addition, the wear resistance of H13 can resist the abrasive wear of oxide scale and slag on the weld surface, keep the wheel surface smooth, and avoid the decline in compaction quality caused by adhesive wear. Since the cantilever link 17 connects the pressure plate 16 and the antinode of the amplitude transformer 9, it is used to transmit the high-frequency vibration generated by the transducer 8 to the pressure plate 16, so that the cantilever link 17 is subjected to high-frequency alternating stress and welding heat radiation during operation. The H13 material has high fatigue strength and good resistance to high-frequency vibration fatigue, and can prevent fatigue fracture or microcracks under long-term high-frequency cyclic load, ensuring the reliability of the vibration transmission path. H13 has a high elastic modulus and low acoustic loss, which helps to reduce the attenuation of ultrasonic vibration energy in the cantilever link 17, allowing the pressure plate 16 to obtain sufficient vibration amplitude. At the same time, H13 has good dimensional stability and a low coefficient of thermal expansion under welding heat, which can maintain the connection stiffness between the cantilever link 17, the amplitude transformer 9, and the pressure plate 16, and avoid loosening of the connection or phase shift caused by temperature changes, thus ensuring the stability and consistency of ultrasonic vibration transmission. After the figure-eight-shaped microgrooves 19 of the impact block 10 push the slag and oxides on the weld surface to both sides, the laminar flow formed by the guide shroud 20 further blows the floating impurities away from the weld surface, preventing the rolling roller 12 from pressing these impurities back into the weld, thereby ensuring the purity of the weld surface and improving the rolling compaction quality. The guide shroud 20 guides the protective gas to the high-temperature area of ​​the weld, forming a protective air curtain between the impact block 10 and the rolling roller 12. This isolates the air, prevents the newly solidified weld surface from being oxidized at high temperatures, reduces oxide scale formation, and is beneficial for subsequent rolling compaction and surface quality control.

[0036] Example 4: A method for processing steel structure plates using automatic arc welding equipment, comprising the following steps: Step 1: First, place the two workpieces 4 on the side of the workbench 1 and between the two clamping plates 3. Then, rotate the screw 5 to bring the clamping plates 3 closer together, thereby clamping the two workpieces 4 and making the mating surfaces of the two workpieces 4 in close contact. Step 2: The external robotic arm drives the mounting base 6 and the lifting slide plate 13 to move down synchronously. When the rolling roller 12 contacts the workpiece 4, the mounting base 6 continues to move down. At this time, the lifting slide plate 13 is restricted by the rolling roller 12, so that the mounting base 6 and the lifting slide plate 13 jointly compress the spring 15. Then, the external robotic arm drives the mounting base 6 to move along the gap between the contact surfaces of the two workpieces 4. At the same time, the welding torch 7 works and makes the end of the welding wire 72 briefly contact the workpiece 4. During this process, the conductive nozzle 71 is energized. When the welding wire 72 is retracted, a strong electric arc is generated between the welding wire 72 and the workpiece 4, which instantly melts the metal of the welding wire 72 and the workpiece 4 and forms a molten pool on the workpiece 4. At the same time, the nozzle 70 sprays protective gas around the molten pool, so that the protective gas forms a protective gas shield around the molten pool and the electric arc, thereby isolating oxygen, nitrogen and other gases in the air. Step 3: The external robotic arm drives the mounting base 6 and welding torch 7 to move forward, thereby melting the corresponding positions of the workpiece 4 in sequence. As the welding torch 7 leaves, the part of the workpiece 4 that was originally melted solidifies into a weld. At this time, the operating transducer 8 transmits high-frequency vibration to the impact block 10 through the amplitude transformer 9. The high-frequency vibrating impact block 10 contacts the weld and applies ultrasonic micro-forging to the contacted weld. Step four: The above-mentioned amplitude rod 9 transmits high-frequency vibration to the pressure plate 16 through the cantilever connecting rod 17, so that the pressure plate 16 transmits ultrasonic energy into the molten pool through the contacting workpiece 4, causing the bubbles in the molten pool to rise. Step 5: The impact block 10 is moved away by the forward-moving mounting seat 6. At this time, the rolling roller 12 contacts the weld and applies rolling pressure to the weld. Step six: After the workpiece 4 is welded, the welding torch 7 stops working, the external robotic arm moves the mounting base 6 upward to reset, so that the spring 15 drives the lifting slide plate 13 to reset. Then, the screw 5 is reversed, so that the clamping plate 3 is released from the workpiece 4. Finally, the welded workpiece 4 is removed.

Claims

1. An automatic arc welding device for processing steel structure panels, comprising: A workbench (1) has symmetrically arranged grooves (2) on its upper surface. A clamping plate (3) is slidably installed in the groove (2). Workpieces (4) are symmetrically placed on the upper surface of the workbench (1) between the two clamping plates (3). The workpieces (4) are steel structure plates. A screw (5) is rotatably installed inside the workbench (1). The screw (5) and the clamping plate (3) form a transmission connection. A mounting seat (6) is set directly above the weld between the two workpieces (4). The upper end of the mounting seat (6) is fixedly connected to an external robotic arm. A welding gun (7) is fixedly installed in the middle of the lower side of the mounting seat (6). The welding gun (7) includes a nozzle (70), a conductive tip (71), and a welding wire (72). The nozzle (70) is fixedly installed in the middle position of the lower side of the mounting base (6). The protective gas delivery pipe on the external robotic arm passes through the mounting base (6) and is connected to the nozzle (70). A conductive nozzle (71) is fixedly installed in the middle position inside the nozzle (70). The wire feeding mechanism on the external robotic arm passes the welding wire (72) through the mounting base (6) and extends into the inner side of the conductive nozzle (71). The characteristic is that a transducer (8) is provided at the rear position of the lower side of the mounting base (6). An amplitude transformer (9) is fixedly installed at the lower end of the transducer (8). An impact block (10) is fixedly installed at the lower end of the amplitude transformer (9). The lower side of the impact block (10) is a concave arc surface. The concave arc surface of the impact block (10) corresponds to the weld between the workpieces (4).

2. The automatic arc welding device for processing steel structure plates according to claim 1, characterized in that, A mounting rod (11) is provided on the lower side of the mounting base (6) and at the rear side of the transducer (8). A rolling roller (12) is rotatably mounted on the lower end of the mounting rod (11). The outer circumferential surface of the rolling roller (12) is a concave arc surface, and the concave arc surface of the rolling roller (12) corresponds to the weld between the workpieces (4).

3. The automatic arc welding device for processing steel structure plates according to claim 2, characterized in that, A lifting slide plate (13) is provided below the mounting base (6) and outside the welding torch (7). Insert rods (14) are fixedly installed on both sides of the upper side of the lifting slide plate (13). The upper end of the insert rod (14) is slidably inserted into the interior of the mounting base (6). A spring (15) is sleeved on the outside of the welding torch (7). The upper end of the spring (15) is fixedly connected to the lower side of the mounting base (6), and the lower end of the spring (15) is fixedly connected to the upper side of the lifting slide plate (13). The transducer (8) and the mounting rod (11) are both fixedly installed on the lower surface of the lifting slide plate (13).

4. The automatic arc welding device for processing steel structure plates according to claim 3, characterized in that, A pressure plate (16) is fixedly installed on the lower side of the lifting slide plate (13). The lower surface of the pressure plate (16) is an arc surface. The lower surface of the pressure plate (16) contacts the symmetrical workpiece (4). The pressure plate (16) and the mounting rod (11) are arranged in a symmetrical position with the welding gun (7) as the center.

5. The automatic arc welding device for processing steel structure plates according to claim 4, characterized in that, Two symmetrical cantilever links (17) are horizontally arranged between the pressure plate (16) and the amplitude rod (9). One end of the cantilever link (17) is fixedly connected to the side of the pressure plate (16) facing the welding gun (7), and the other end of the cantilever link (17) is fixedly connected to the antinode of the amplitude rod (9).

6. The automatic arc welding device for processing steel structure plates according to claim 4, characterized in that, An isolation pad (18) is provided between the upper end of the transducer (8) and the lifting slide plate (13), and between the upper side of the pressure plate (16) and the lifting slide plate (13). The isolation pad (18) is made of silicone rubber.

7. The automatic arc welding device for processing steel structure plates according to claim 1, characterized in that, The impact block (10) has a micro-groove (19) on its concave arc surface. The micro-groove (19) has a figure-eight structure and the narrow end of the micro-groove (19) faces the welding gun (7).

8. An automatic arc welding device for processing steel structure plates according to claim 5, characterized in that, The rolling roller (12) and the cantilever connecting rod (17) are both made of air-cooled hardening hot work die steel, and a flow guide (20) is provided at the lower end of the nozzle (70) facing the impact block (10).

9. A method for processing steel structure plates using the automatic arc welding equipment according to claim 8, characterized in that, Includes the following steps: Step 1: First, place the two workpieces (4) on the side of the workbench (1) and between the two clamping plates (3). Then, rotate the screw (5) to bring the clamping plates (3) closer to each other, thereby clamping the two workpieces (4) and making the mating surfaces of the two workpieces (4) in close contact. Step two: The external robotic arm drives the mounting base (6) and the lifting slide plate (13) to move down synchronously. When the rolling roller (12) contacts the workpiece (4), the mounting base (6) continues to move down. At this time, the lifting slide plate (13) is restricted by the rolling roller (12), so that the mounting base (6) and the lifting slide plate (13) compress the spring (15) together. Then, the external robotic arm drives the mounting base (6) to move along the gap between the contact surfaces of the two workpieces (4). At the same time, the welding torch (7) works and makes the welding wire (7) 2) The end of the welding wire (72) briefly contacts the workpiece (4). During this process, the conductive nozzle (71) is energized. When the welding wire (72) is pulled back, a strong electric arc is generated between the welding wire (72) and the workpiece (4), which instantly melts the metal of the welding wire (72) and the workpiece (4) and forms a molten pool on the workpiece (4). At the same time, the nozzle (70) sprays protective gas around the molten pool, so that the protective gas forms a protective gas shield around the molten pool and the electric arc, thereby isolating oxygen, nitrogen and other gases in the air. Step 3: The external robotic arm drives the mounting base (6) and welding torch (7) to move forward, thereby melting the corresponding positions of the workpiece (4) in sequence. As the welding torch (7) leaves, the part of the workpiece (4) that was originally melted solidifies into a weld. At this time, the operating transducer (8) transmits high-frequency vibration to the impact block (10) through the amplitude rod (9). The high-frequency vibrating impact block (10) contacts the weld and applies ultrasonic micro-forging to the contacted weld. Step 4: The above-mentioned amplitude rod (9) transmits high-frequency vibration to the pressure plate (16) through the cantilever connecting rod (17), so that the pressure plate (16) transmits ultrasonic energy into the molten pool through the contacting workpiece (4), causing the bubbles in the molten pool to float to the surface. Step 5, the impact block (10) is moved away by the forward mounting seat (6), at which time the rolling roller (12) contacts the weld and applies rolling pressure to the weld; Step 6: After the workpiece (4) is welded, the welding gun (7) stops working, the external robotic arm drives the mounting base (6) to move up and reset, so that the spring (15) drives the lifting slide plate (13) to reset. Then, the screw (5) is reversed so that the clamp (3) is released from the workpiece (4). Finally, the welded workpiece (4) is removed.

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