Electric arc welding device for steel structure

Abstract

The invention relates to the technical field of welding manufacturing, in particular to a steel structure electric arc welding device which comprises a clamping arm, a cold conduction assembly, a heat conduction assembly and a compensation assembly. The clamping arm is connected with the lower part of the welding arm; the cold conduction assembly is connected with the clamping arm, the heat conduction assembly is connected with the upper portion of the welding arm, and the compensation assembly is connected with the heat conduction assembly. A workpiece is clamped through the clamping arm, the heat conduction assembly rolls a weld joint in the welding process to enable crystal grains to be formed again, heat absorbed in the rolling process drives the compensation assembly to drive the workpiece to conduct compensation displacement, residual stress is reduced, and meanwhile the temperature difference formed between the heat conduction assembly and cooling liquid through the absorbed heat is utilized to enable the heat conduction assembly to conduct heat dissipation. The base metal is cooled and conducted to the section of the welding seam in the mode of first rapid cooling and then slow cooling, and therefore the situation that the core residual stress is too large due to the temperature gradient is avoided; the problem that when a large-thickness steel structure is welded, the cooling speed of the weld surface and the cooling speed of the core are different, and consequently large residual stress exists in the core position is solved.

Description

Technical Field

[0001] The invention relates to the technical field of welding manufacturing, and in particular to an arc welding device for steel structures. Background Art

[0002] Arc welding equipment mainly converts high-voltage, low-current grid electricity into low-voltage, high-current welding electricity, and uses this current to stimulate a high-temperature arc between the welding material and the steel structure workpiece. The extremely high temperature of the arc will instantly melt the welding material and the workpiece, forming a liquid molten pool. As the welding gun moves, the molten pool will cool and solidify to achieve a permanent metallurgical bond between the steels.

[0003] Due to the high concentration of energy in arc welding, the metal at the weld position can be heated to a molten state within a few seconds. The metal at the weld area will expand due to the heat, but the surrounding parent material is still in a low temperature state, which will prevent the free expansion of the metal in the hot zone. At this time, the metal in the hot zone will be subjected to compressive stress, and when the local temperature reaches the temperature at which the yield strength of the material decreases or even enters the plastic state, plastic deformation will occur under the compressive stress. When the welding heat source is removed, the shrinkage amount will change during the cooling and shrinkage process due to the previous plastic deformation, thereby causing residual stress to be generated. A method for suppressing the generation of residual stress in arc welding has been proposed in the prior art, such as a welding residual stress control method and device based on longitudinal cyclic load with patent publication number CN113210799B, which applies a longitudinal cyclic load to the workpiece to be welded through a stretching device, so that the workpiece produces a preset elastic deformation, and welding is performed under the preset elastic deformation state. After the welding is completed, the longitudinal cycle is maintained for a preset time. Load, after the preset time is reached, the preset longitudinal cyclic load is removed, and the rebound of the preset elastic deformation is used to offset the shrinkage deformation generated during the cooling process of the weld; however, the following problems still exist: when welding large and complex steel structures, due to the high rigidity and large thickness of the workpiece itself, the heat is not evenly transferred in the thickness direction during the welding process, resulting in a huge temperature gradient between the surface and the core, and the surface cooling rate of the weld will be faster than the cooling rate of the core, so during the cooling process, after the surface weld is cooled, it will form the same constraint as the parent material in the thickness direction, causing residual stress in the core at multiple angles, and the peak value of this welding residual stress will be much higher than the stress on the surface, and for thick steel structures, its own high rigidity makes it difficult to release stress through overall deformation; at the same time, the difference in cooling rate between the core and the surface will produce a stress field with extremely complex size and distribution. Therefore, it is impossible to effectively solve the residual stress generated by this complex temperature gradient simply by applying a rebound force.

[0004] In view of the above situation, in order to overcome the above technical problems, the present invention designs a steel structure arc welding device. Summary of the Invention

[0005] The present invention provides a steel structure arc welding device, which solves the problem of large residual stress in the core position caused by different cooling rates between the weld surface and the core during welding of thick steel structures. By using a hot roller to roll over the uncooled weld surface during welding, the high-temperature austenite zone is plastically deformed, dynamic recrystallization is triggered, and weld performance is improved. A small amount of heat energy is recovered to drive the workpiece for compensatory displacement, thereby reducing residual stress. At the same time, temperature difference power generation is generated between the recovered heat energy and the coolant channel. The temperature difference change is used to control the flow rate of the coolant in the upper clamping plate and the lower clamping plate in real time to cool the base material, thereby achieving forced lateral cooling in a high-temperature state and slowing down the cooling rate at medium and low temperatures, thereby avoiding a large temperature gradient in the weld cross section and reducing residual stress.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A steel structure arc welding device; comprising a welding arm, and also comprising a clamping arm, a cold conduction component, a heat conduction component and a compensation component; the clamping arm is connected to the lower part of the welding arm; the cold conduction component is connected to the clamping arm, and during welding, the cold conduction component transports coolant to the contact part between the clamping arm and the workpiece; the heat conduction component is connected to the upper part of the welding arm, and during the movement of the welding arm along the preset welding path, the welding arm drives the heat conduction component to move along the same path, and during the movement of the heat conduction component, the heat conduction component absorbs the heat of the weld, and the more heat it absorbs, the faster the cold conduction component transports the coolant; the compensation component is connected to the heat conduction component, and during the movement of the welding arm, the heat conduction component absorbs the heat of the weld and drives the compensation component to drive the workpiece to perform compensatory displacement.

[0008] Preferably, the clamping arm includes a mounting arm, a sliding seat, a sliding block, an upper clamping plate, a lower clamping plate and an adjusting piece; the mounting arm is connected to the lower part of the welding arm; the sliding seat is connected to the mounting arm; the sliding block is slidably mounted on the sliding seat; the upper clamping plate is slidably mounted on the sliding block; the lower clamping plate is fixedly mounted on the sliding block; and the adjusting piece is connected to the upper clamping plate.

[0009] In the above scheme, after the steel structure workpiece to be welded is clamped and fixed by the upper clamping plate and the lower clamping plate before welding, the restriction of other degrees of freedom of the workpiece can be fixed by a welding table or a welding fixture. During the welding process, the degrees of freedom of the workpiece in the left and right directions are restricted by the welding fixture. The upper clamping plate and the lower clamping plate will limit the degrees of freedom of the workpiece in the vertical direction, and the movement of the workpiece in the front and rear directions is synchronized with the upper clamping plate and the lower clamping plate. When no compensation is required, the upper clamping plate and the lower clamping plate will not move. When compensation is required, the upper clamping plate and the lower clamping plate will drive the workpiece to move at the micron level for compensation, thereby reducing residual stress.

[0010] Preferably, the sliding seat is provided with a limiting piece on both sides; the adjusting piece comprises a tension spring, an adjusting screw hole and an adjusting screw; the tension spring is connected between the upper clamping plate and the sliding block; the sliding block is provided with an adjusting screw hole; and the adjusting screw is installed on the adjusting screw hole.

[0011] In the above scheme, the limiting piece can be a high-precision micrometer or a precise screw rod controlled stop block. Before welding, the maximum displacement compensation required for this welding can be set according to the welding process and welding material in advance. When the maximum displacement compensation is reached, it cannot move further, thereby eliminating the generation of excessive compensation. Even if the pressure generated by the heat conduction assembly and the compensation assembly continues to rise, the excess force will act on the limiting piece and the fixed rack of the welding arm.

[0012] Preferably, the cold conduction assembly comprises a cooling liquid cavity, a communication pipeline, a cooling liquid flow channel, a cooling liquid pump, a power generation module, an inlet pipe and an outlet pipe; the cooling liquid cavity is arranged in the upper clamping plate and the lower clamping plate; the communication pipeline is connected between the upper clamping plate and the lower clamping plate; the cooling liquid pump is installed in the cooling liquid flow channel; the power generation module is electrically connected with the cooling liquid pump; the inlet pipe is connected between the upper clamping plate and the cooling liquid flow channel; and the outlet pipe is connected with the lower clamping plate.

[0013] In the above scheme, the cooling liquid pump rotates to guide the cooling liquid into the cooling liquid cavity of the upper clamping plate and the lower clamping plate, so that the cooling liquid can cool the steel structure base material part to be welded. At this time, the heat will be dissipated to the air from the upper and lower surfaces to become transversely cooled by the base material, so that the cooling of the entire weld cross section is more synchronized and uniform, greatly reducing the difference in cooling speed between the weld surface and the core, and compared with air slow cooling, this forced cooling method can inhibit the coarsening of the grain, thereby improving the strength and toughness of the weld, and achieving the purpose of improving the comprehensive mechanical properties.

[0014] Preferably, the communication pipeline is a sealed telescopic structure.

[0015] In the above scheme, the telescopic communication pipeline can make the cooling liquid flow between the upper clamping plate and the lower clamping plate intercommunicate, and can ensure that the flow path of the cooling liquid will not be affected when adjusting the distance between the upper clamping plate and the lower clamping plate, while improving the stability between the upper clamping plate and the lower clamping plate.

[0016] Preferably, the heat conduction assembly comprises a heat recovery arm, a heat roller and a flexible heat pipe; the heat recovery arm is connected with the upper part of the welding arm; the heat roller is rollingly installed at the end position of the heat recovery arm, and the heat roller is a spherical structure; and the flexible heat pipe is connected between the heat recovery arm and the compensation assembly.

[0017] In the above scheme, when the welding arm drives the welding head to move, the hot roller will roll across the weld surface along the moving path of the welding head after a delay of a period of time. On the one hand, the hot roller will cause plastic deformation of the high-temperature austenite zone, triggering dynamic recrystallization, so that the coarse and directional cast columnar crystals are broken under the action of rolling pressure, and re-nucleate and grow to form small and uniform equiaxed crystals, thereby improving the weld performance. At the same time, it can eliminate the tiny pores and shrinkage defects generated during the welding process and reduce stress concentration; on the other hand, the hot roller will absorb part of the heat and transfer the absorbed heat to the compensation component through the flexible heat pipe.

[0018] Preferably, the compensation assembly includes a compensation chamber, a compensation piston, a compensation spring and a transmission member; the compensation chamber is opened in the mounting arm, and the compensation chamber is sealed and filled with a thermal expansion medium; the compensation piston is slidably installed in the compensation chamber, and one end of the compensation piston extends out of the compensation chamber; the compensation spring is connected between the compensation piston and the compensation chamber; and the transmission member is connected to the end of the compensation piston extending out of the compensation chamber.

[0019] In the above scheme, the flexible heat pipe transfers the recovered heat to the thermal expansion medium in the compensation chamber (considering the material / total volume). By recovering the heat, the thermal expansion medium expands, thereby pushing the compensation piston to slide, and the sliding movement of the compensation piston drives the transmission part to rotate.

[0020] Preferably, the transmission member includes a rotating fulcrum and a telescopic lever; the rotating fulcrum is arranged in the mounting arm; the telescopic lever is rotatably mounted on the rotating fulcrum, and one end of the telescopic lever is connected to the compensation piston, and the other end is connected to the sliding block.

[0021] In the above scheme, when the compensation piston pushes the telescopic lever, the sliding block can be driven to move, thereby driving the upper clamping plate and the lower clamping plate to drive the workpiece to perform compensating movement, and the displacement of the workpiece can be greatly reduced by adjusting the position of the fulcrum. Moreover, since the force arm from the fulcrum to one end of the compensation piston is longer, the thrust of the compensation piston can be further increased, which helps to improve the compensation force applied to the workpiece.

[0022] Preferably, the power generation module is a semiconductor thermoelectric power generation sheet, and both ends of the power generation module are connected to the coolant flow channel and the compensation cavity respectively through copper sheets.

[0023] In the above scheme, cold energy and heat energy are respectively conducted to the two ends of the power generation module through the copper sheet, so that a temperature difference is generated at both ends of the power generation module, thereby generating electrical energy to drive the coolant pump to rotate, accelerating the circulation speed of the coolant, and the greater the temperature difference, the greater the power generation will be, which will make the speed of the coolant pump faster, increase the flow rate of the coolant, and ensure that the peak heat can be taken away. Although a fast cooling rate can maximize grain refinement, if the cooling rate exceeds the critical cooling rate, the austenite will not be able to be transformed into ferrite and pearlite, but will be transformed into high hardness and low plasticity martensite. The power generation module can slow down the flow rate of the coolant in the subsequent cooling process as the temperature difference decreases, thereby realizing a cooling scheme that is fast at first and then slow to match the temperature change of the weld.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. Compared with the existing arc welding automatic welding equipment, the present invention cools the base material by circulating the coolant in the upper clamping plate and the lower clamping plate that clamp the base material, so that the heat at the weld position is dissipated from the upper and lower surfaces to the air and is laterally cooled by the base material, making the cooling of the entire weld cross section more synchronized and uniform, greatly reducing the difference in cooling rate between the weld surface and the core, and compared with the slow cooling of air, this forced cooling method can inhibit the coarsening of grains, thereby improving the strength and toughness of the weld, and during the welding process, the hot roller moving in the same path as the welding arm will roll the weld, forcing the high-temperature austenite zone to plastically deform, inducing dynamic recrystallization, so that the coarse and highly directional cast columnar crystals are broken under the action of rolling pressure, and re-nucleate and grow to form fine and uniform equiaxed crystals, thereby improving the weld performance, and at the same time, it can eliminate the tiny pores and shrinkage defects generated during the welding process, reduce stress concentration, and further improve the weld performance.

[0026] 2. The present invention recycles a small portion of the weld heat through a hot roller. This heat will drive the thermal expansion medium in the compensation chamber to expand, thereby pushing the compensation piston to slide. The sliding motion of the compensation piston then drives the telescopic lever to drive the upper clamping plate and the lower clamping plate to slide. Under the setting conditions of the limit piece and the force arm length at both ends of the telescopic lever, the upper clamping plate and the lower clamping plate will drive the workpiece to perform micron-level dynamic displacement compensation, thereby removing the tension generated by the base material on the weld during the solidification stage, preventing the occurrence of thermal cracks, and significantly reducing the residual stress peak.

[0027] 3. The present invention controls the rotation speed of the coolant pump by setting a temperature difference power generation module, heats one end of the power generation module by heat recovered by the hot roller, and uses the coolant in the coolant channel to cool the other end of the power generation module, thereby generating a temperature difference, and this temperature difference will automatically change according to the change of the weld temperature, thereby slowing down the flow rate of the coolant when the temperature difference decreases, thereby reducing the cooling rate of the weld, so that the cooling process of the weld is fast at first and then slow, cooling quickly at high temperature to inhibit the increase of austenite grains, obtaining the desired structure at a moderate cooling rate at intermediate temperature to avoid the formation of martensite, and finally cooling slowly at low temperature to release hydrogen atoms to prevent the generation of cold cracks, while releasing residual stress to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 It is the overall structural diagram of the present invention;

[0030] Figure 2 This is a schematic diagram of the internal structure of the mounting arm of the present invention;

[0031] Figure 3 for Figure 2 A magnified view of the structure at center A;

[0032] Figure 4 Schematic diagram of the clamping arm structure of the present invention;

[0033] Figure 5 Schematic diagram of the connection relationship between the transmission member and the sliding block of the present invention;

[0034] Figure 6 for Figure 2 A magnified view of the structure at point B in the middle;

[0035] Figure 7 This is a cross-sectional view of the internal structure of the compensation cavity of the present invention;

[0036] Figure 8 for Figure 7 Enlarged view of the structure at point C in the middle.

[0037] In the figure: 1, welding arm; 2, clamping arm; 21, mounting arm; 22, sliding seat; 221, limiting piece; 23, sliding block; 24, upper clamping plate; 25, lower clamping plate; 26, adjusting piece; 261, tension spring; 262, adjusting screw hole; 263, adjusting bolt; 3, cold conduction assembly; 31, cooling liquid cavity; 32, communication pipeline; 33, cooling liquid flow channel; 34, cooling liquid pump; 35, power generation module; 36, liquid inlet pipe; 37, liquid outlet pipe; 4, heat conduction assembly; 41, heat recovery arm; 42, heat roller; 43, flexible heat pipe; 5, compensation assembly; 51, compensation cavity; 52, compensation piston; 53, compensation spring; 54, transmission piece; 541, rotating fulcrum; 542, telescopic lever. DETAILED DESCRIPTION

[0038] In order to better understand the above technical solutions, the above technical solutions will be described in detail below in combination with the drawings of the specification and specific embodiments.

[0039] Please refer to Figures 1 to 8 , the present application provides a steel structure electric arc welding device, technical scheme as follows:

[0040] As a specific embodiment of the present application, refer to Figure 1 and Figure 2 A steel structure electric arc welding device; comprising a welding arm 1, further comprising a clamping arm 2, a cold conduction assembly 3, a heat conduction assembly 4 and a compensation assembly 5; the clamping arm 2 is connected with the lower part of the welding arm 1; the cold conduction assembly 3 is connected with the clamping arm 2, and the cold conduction assembly 3 delivers cooling liquid to the contact part of the clamping arm 2 and the workpiece during welding; the heat conduction assembly 4 is connected with the upper part of the welding arm 1, and the heat conduction assembly 4 moves along the same path as the welding arm 1 moves along the preset welding path, and the heat conduction assembly 4 absorbs the heat of the weld during movement, and the more heat absorbed, the faster the cooling liquid delivered by the cold conduction assembly 3; the compensation assembly 5 is connected with the heat conduction assembly 4, and the heat conduction assembly 4 drives the compensation assembly 5 to drive the workpiece to make compensation displacement during movement with the welding arm 1.

[0041] As a specific embodiment of the present application, refer to Figure 2 , Figure 3 and Figure 4The clamping arm 2 includes a mounting arm 21, a sliding seat 22, a sliding block 23, an upper clamping plate 24, a lower clamping plate 25 and an adjusting piece 26; the mounting arm 21 is connected to the lower part of the welding arm 1; the sliding seat 22 is connected to the mounting arm 21; the sliding block 23 is slidably mounted on the sliding seat 22; the upper clamping plate 24 is slidably mounted on the sliding block 23; the lower clamping plate 25 is fixedly mounted on the sliding block 23; and the adjusting piece 26 is connected to the upper clamping plate 24. Before welding, the steel structure workpiece to be welded is clamped and fixed by the upper clamping plate 24 and the lower clamping plate 25. The other degrees of freedom of the workpiece can be restricted by a welding table or a welding fixture. During welding, the degrees of freedom of the workpiece in the left and right directions are restricted by the welding fixture. The upper clamping plate 24 and the lower clamping plate 25 will limit the degrees of freedom of the workpiece in the vertical direction, and the movement of the workpiece in the front and rear directions is synchronized with the upper clamping plate 24 and the lower clamping plate 25. When no compensation is required, the upper clamping plate 24 and the lower clamping plate 25 will not move. When compensation is required, the upper clamping plate 24 and the lower clamping plate 25 will drive the workpiece to move at the micron level for compensation, thereby reducing residual stress.

[0042] As a specific embodiment of the present invention, refer to Figure 3 and Figure 4 , limit members 221 are set on both sides of the sliding seat 22; the adjusting member 26 includes a tension spring 261, an adjusting screw hole 262 and an adjusting bolt 263; the tension spring 261 is connected between the upper clamping plate 24 and the sliding block 23; an adjusting screw hole 262 is opened on the sliding block 23; the adjusting bolt 263 is installed on the adjusting screw hole 262. The limiter 221 here can be a stopper controlled by a high-precision micrometer or a precision screw. Before welding, the maximum displacement compensation required for this welding can be set in advance according to the welding process and welding materials. When the maximum displacement compensation is reached, it will no longer be able to move, thereby preventing the occurrence of over-compensation. Even if the pressure generated by the heat conduction component 4 and the compensation component 5 continues to increase, the excess force will act on the limiter 221 and the frame fixed to the welding arm 1; for example, for the welding of two 20mm thick Q345 steel plates, during the cooling from 800°C to room temperature, thermal shrinkage will cause the required compensation displacement to be generally in the range of 100 to 300μm. Before welding, the operator can set the limiter 221 to allow displacement within this range.

[0043] As a specific embodiment of the present invention, refer to Figure 4 、 Figure 5 and Figure 8The cold conduction component 3 includes a cooling liquid chamber 31, a connecting pipe 32, a cooling liquid flow channel 33, a cooling liquid pump 34, a power generation module 35, a liquid inlet pipe 36 and a liquid outlet pipe 37; the cooling liquid chamber 31 is opened in the upper clamping plate 24 and the lower clamping plate 25; the connecting pipe 32 is connected between the upper clamping plate 24 and the lower clamping plate 25; the cooling liquid pump 34 is installed in the cooling liquid flow channel 33; the power generation module 35 is electrically connected to the cooling liquid pump 34; the liquid inlet pipe 36 is connected between the upper clamping plate 24 and the cooling liquid flow channel 33; and the liquid outlet pipe 37 is connected to the lower clamping plate 25. The coolant flow channel 33 is connected to the coolant storage container through a hose. The coolant pump 34 rotates to guide the coolant to the coolant chamber 31 of the upper clamping plate 24 and the lower clamping plate 25, allowing the coolant to cool the steel structure base material portion to be welded. At this time, the heat will be dissipated from the upper and lower surfaces to the air and then be cooled laterally by the base material, making the cooling of the entire weld cross section more synchronized and uniform, greatly reducing the difference in cooling rate between the weld surface and the core. Compared with slow cooling by air, this forced cooling method can inhibit grain coarsening, thereby improving the strength and toughness of the weld and achieving the purpose of improving the overall mechanical properties. The liquid outlet pipe 37 is connected to the coolant recovery container and can cool the heated coolant again and guide it back to the coolant storage container for easy recycling. The connecting pipe 32 is a sealed and retractable structure. The retractable connecting pipe 32 can make the coolant flow between the upper clamping plate 24 and the lower clamping plate 25 interconnected, and can ensure that when the distance between the upper clamping plate 24 and the lower clamping plate 25 is adjusted, the flow path of the coolant will not be affected, and at the same time can improve the stability between the upper clamping plate 24 and the lower clamping plate 25.

[0044] As a specific embodiment of the present invention, refer to Figure 2 、 Figure 6 and Figure 7The heat conduction component 4 includes a heat recovery arm 41, a hot roller 42 and a flexible heat pipe 43; the heat recovery arm 41 is connected to the upper part of the welding arm 1 and is made of a material with a high thermal conductivity coefficient; the hot roller 42 is rollingly installed at the end position of the heat recovery arm 41, and the hot roller 42 is a spherical structure and is made of a material with a high thermal conductivity coefficient; the flexible heat pipe 43 is connected between the heat recovery arm 41 and the compensation component 5. The flexible heat pipe is a high-temperature sodium-based or potassium-based heat pipe with a sintered metal powder core structure. It can operate efficiently at a hot end temperature of up to 900°C. It is connected to the heat recovery arm 41 through a silver-brazed copper saddle and is connected to the compensation cavity 51 through a thermally conductive high-pressure flange to ensure optimal heat flow into the thermal expansion medium. As the welding arm 1 drives the welding head to move, the hot roller 42 will roll across the weld surface along the moving path of the welding head after a delay of a period of time. On the one hand, the hot roller 42 will cause the high-temperature austenite zone to plastically deform, inducing dynamic recrystallization, so that the coarse, highly directional cast columnar crystals are broken under the action of the rolling pressure, and re-nucleate and grow to form small, uniform equiaxed crystals, thereby improving the weld performance and eliminating the tiny pores and shrinkage defects generated during the welding process, reducing stress concentration; on the other hand, the hot roller 42 will absorb part of the heat and conduct the absorbed heat to the compensation group through the flexible heat pipe 43. Part 5; the distance between the heat recovery arm 41 and the welding arm 1 can be adjusted according to the workpiece. The distance determines the delay time of the hot roller 42 rolling the weld seam relative to the start of welding, and the welding arm 1 is automatically welded by program intelligent control. It can be set to continue moving after the welding arm 1 is completed (and the moving path of the hot roller 42 is exactly the same as the moving path of the welding head on the welding arm 1) until the hot roller 42 rolls over all the welds and then stops moving; the welding arm 1 uses an automatic or semi-automatic arc welding structure and an automatic wire feeding system to ensure that the welding gun does not need to move down after the solder becomes shorter, so the hot roller 42 does not need to move down synchronously.

[0045] As a specific embodiment of the present invention, refer to Figure 7The compensation assembly 5 includes a compensation chamber 51, a compensation piston 52, a compensation spring 53 and a transmission member 54; the compensation chamber 51 is opened in the mounting arm 21; the compensation piston 52 is slidably installed in the compensation chamber 51, and one end of the compensation piston 52 extends out of the compensation chamber 51; the compensation spring 53 is connected between the compensation piston 52 and the compensation chamber 51; the transmission member 54 is connected to the end of the compensation piston 52 extending out of the compensation chamber 51. The flexible heat pipe 43 transfers the recovered heat to the thermal expansion medium (considering the material / total volume) in the compensation chamber 51. The recovered heat causes the thermal expansion medium to expand, thereby pushing the compensation piston 52 to slide. The sliding movement of the compensation piston 52 drives the transmission member 54 to rotate. The thermal expansion medium here can be R-1233zd or R-245fa, both of which have a good pressure-temperature curve and a pressure range suitable for hydraulic components without corrosive to common metal materials. R-1233zd can boil at 40 to 50°C and generate a driving force of 10 to 15 atmospheres at around 150°C. The compensation chamber 51 and The cross-sectional size of the compensating piston 52 can be designed based on the size and weight of the steel structure to be welded. For R-1233zd, a pressure of approximately 10 bar is generated at approximately 150°C, and a thrust of approximately 1 ton is generated at a cross-sectional radius of 5 cm. Displacement compensation can reduce the tension exerted by the parent material on the weld during cooling and solidification, preventing the occurrence of thermal cracks and significantly reducing the peak residual stress. Since the compensating piston 52 can be pushed to the farthest end by the thermal expansion medium at 150°C, the weld solidifies and hardens when cooled to below 500°C, ensuring that even if the thermal expansion medium subsequently cools to a contracted state, the compensating piston 52 will not retreat.

[0046] As a specific embodiment of the present invention, refer to Figure 5 and Figure 7 The transmission member 54 includes a pivot point 541 and a telescopic lever 542. The pivot point 541 is disposed within the mounting arm 21. The telescopic lever 542 is rotatably mounted on the pivot point 541, and one end of the telescopic lever 542 is connected to the compensating piston 52, while the other end is connected to the sliding block 23. When the compensating piston 52 pushes the telescopic lever 542, the sliding block 23 can be driven to move, thereby driving the upper clamping plate 24 and the lower clamping plate 25 to drive the workpiece to perform compensatory movement. Both ends of the telescopic lever 542 are configured as telescopic structures to ensure that there is no motion interference. The displacement of the workpiece can be significantly reduced by adjusting the position of the pivot point (i.e., adjusting the ratio of the two lever arms). Furthermore, since the lever arm from the pivot point to one end of the compensating piston 52 is longer, the thrust of the compensating piston 52 can be further increased, thereby helping to improve the compensating force applied to the workpiece.

[0047] As a specific embodiment of the present invention, refer to Figure 7and Figure 8 The power generation module 35 is a semiconductor temperature difference power generation sheet. The two ends of the power generation module 35 are connected to the coolant channel 33 and the compensation cavity 51 respectively through copper sheets. The coolant is a special insulating coolant of deionized water, and the thermal expansion medium R-1233zd is an insulating medium. Therefore, the copper sheet here is in direct contact with the two media without short circuit leakage and other phenomena. After the copper sheet is inserted, it is necessary to ensure that the original sealing of the compensation cavity 51 and the coolant channel 33 is not destroyed. Welding or the use of a seal that can withstand the corresponding temperature and pressure can be considered. The cold energy and heat energy are respectively conducted to the two ends of the power generation module 35 through the copper sheet, so that a temperature difference is generated at both ends of the power generation module 35, thereby generating electricity to drive the coolant pump 34 to rotate (in order to ensure the normal operation of the coolant pump 34 and have an adaptive speed regulation function, a boost-stabilizer module with a maximum power point tracking function can be added), accelerating the circulation speed of the coolant, and the greater the temperature difference, the greater the power generation will be, making the speed of the coolant pump 34 faster, increasing the flow rate of the coolant, and ensuring that the peak heat can be taken away. Although a fast cooling rate can maximize grain refinement, a cooling rate exceeding the critical cooling rate will cause the austenite to be unable to transform into ferrite and pearlite, but to transform into high hardness, low plasticity martensite, through the power generation module 35. As the temperature difference decreases, the flow rate of the coolant can be slowed down in the subsequent cooling process, thereby realizing a cooling scheme that is fast first and then slow in accordance with the temperature change of the weld. Rapid cooling is performed at high temperatures (greater than 800°C) to inhibit the increase of austenite grains. At intermediate temperatures (500 to 800°C), the desired structure (ferrite + pearlite, or bainite) is obtained at a moderate cooling rate to avoid the formation of martensite. Finally, slow cooling is performed at low temperatures (below 500°C) so that the hydrogen atoms in the steel structure have enough time and energy to diffuse from the weld, reducing the risk of cold cracks. Moreover, between 300 and 500°C, the steel still has a certain creep and plastic deformation capacity. Slow cooling in this state can release the residual stress to a certain extent.

[0048] Workflow: Before welding, set the maximum compensation displacement according to the workpiece to be welded. Adjust the limiter 221 to limit the maximum displacement that the sliding block 23 can produce. The workpiece is restrained by the welding table or welding fixture to limit its degree of freedom in the non-compensation direction. Adjust the upper clamping plate 24 by turning the adjusting bolt 263 so that the upper clamping plate 24 and the lower clamping plate 25 clamp the workpiece. Connect the coolant flow channel 33 to a low-temperature coolant storage container through a hose, and connect the liquid outlet pipe 37 to a coolant recovery container.

[0049] After completing the pre-welding preparation work, welding begins. The welding arm 1 is controlled by an automatic program to weld according to a preset path. In the process of the welding arm 1 driving the welding head to move, the hot roller 42 will roll over the weld surface according to the moving path of the welding head after a delay, causing the high-temperature austenite zone to plastically deform, inducing dynamic recrystallization, and improving the weld performance. At the same time, the hot roller 42 will absorb part of the heat when rolling over the weld surface, and transfer the heat to the thermal expansion medium in the compensation cavity 51 through the flexible heat pipe 43. The thermal expansion medium absorbs heat and expands to push the compensation piston 52 to slide. The sliding of the compensation piston 52 will drive the telescopic lever 542 to rotate around the rotating fulcrum 541. The telescopic lever 542 drives the workpiece clamped by the upper clamping plate 24 and the lower clamping plate 25 through the sliding block 23 to perform micron-level displacement compensation, greatly reducing the residual stress peak; in the heat As the temperature of the expansion medium rises, since the two ends of the power generation module 35 are connected to the coolant flow channel 33 and the compensation chamber 51 respectively through copper sheets, a large temperature difference will be generated at the two ends of the power generation module 35, thereby generating electrical energy to drive the coolant pump 34 to rotate. The rotation of the coolant pump 34 can pump the coolant from the external low-temperature coolant storage container to the coolant chamber 31 of the upper clamping plate 24 and the lower clamping plate 25, and after heat exchange with the parent material, it is recovered to the external coolant recovery container through the liquid outlet pipe 37. As the temperature difference between the two ends of the power generation module 35 becomes larger, the power generation will increase, the rotation speed of the coolant pump 34 will be faster, the flow rate of the coolant will be increased, and the peak heat can be taken away. In the subsequent cooling process, as the temperature difference decreases, the flow rate of the coolant will slow down, so that the residual stress can be released to a certain extent.

[0050] The basic principles, main features, and advantages of the present invention are shown and described above. It should be understood by those skilled in the art that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention as claimed, which is defined by the appended claims and their equivalents.

Claims

1. An arc welding device for steel structures, comprising a welding arm (1), characterized in that: The invention also includes a clamping arm (2), a cold conduction component (3), a heat conduction component (4) and a compensation component (5); the clamping arm (2) is connected to the lower part of the welding arm (1); the cold conduction component (3) is connected to the clamping arm (2), and during the welding process, the cold conduction component (3) delivers coolant to the contact part between the clamping arm (2) and the workpiece; the heat conduction component (4) is connected to the upper part of the welding arm (1), and during the movement of the welding arm (1) along the preset welding path, the heat conduction component (4) is driven to move along the same path, and during the movement of the heat conduction component (4), the heat conduction component (4) absorbs the heat of the weld, and the more heat it absorbs, the faster the cold conduction component (3) delivers the coolant; the compensation component (5) is connected to the heat conduction component (4), and during the movement of the welding arm (1), the heat conduction component (4) absorbs the heat of the weld and drives the compensation component (5) to drive the workpiece to perform compensation displacement.

2. The steel structure arc welding device according to claim 1, characterized in that: The clamping arm (2) comprises a mounting arm (21), a sliding seat (22), a sliding block (23), an upper clamping plate (24), a lower clamping plate (25) and an adjusting member (26); the mounting arm (21) is connected to the lower portion of the welding arm (1); the sliding seat (22) is connected to the mounting arm (21); the sliding block (23) is slidably mounted on the sliding seat (22); the upper clamping plate (24) is slidably mounted on the sliding block (23); the lower clamping plate (25) is fixedly mounted on the sliding block (23); and the adjusting member (26) is connected to the upper clamping plate (24).

3. The steel structure arc welding device according to claim 2, characterized in that: Limiting members (221) are provided on both sides of the sliding seat (22); the adjusting member (26) includes a tension spring (261), an adjusting screw hole (262) and an adjusting bolt (263); the tension spring (261) is connected between the upper clamping plate (24) and the sliding block (23); an adjusting screw hole (262) is provided on the sliding block (23); and the adjusting bolt (263) is installed on the adjusting screw hole (262).

4. The steel structure arc welding device according to claim 2, characterized in that: The cold conduction component (3) comprises a cooling liquid cavity (31), a connecting pipe (32), a cooling liquid flow channel (33), a cooling liquid pump (34), a power generation module (35), a liquid inlet pipe (36) and a liquid outlet pipe (37); the cooling liquid cavity (31) is opened in the upper clamping plate (24) and the lower clamping plate (25); the connecting pipe (32) is connected between the upper clamping plate (24) and the lower clamping plate (25); the cooling liquid pump (34) is installed in the cooling liquid flow channel (33); the power generation module (35) is electrically connected to the cooling liquid pump (34); the liquid inlet pipe (36) is connected between the upper clamping plate (24) and the cooling liquid flow channel (33); and the liquid outlet pipe (37) is connected to the lower clamping plate (25).

5. The steel structure arc welding device according to claim 4, characterized in that: The communicating pipe (32) is a sealed and retractable structure.

6. The steel structure arc welding device according to claim 1, characterized in that: The heat conduction component (4) comprises a heat recovery arm (41), a heat roller (42) and a flexible heat pipe (43); the heat recovery arm (41) is connected to the upper part of the welding arm (1); the heat roller (42) is rollingly mounted at the end position of the heat recovery arm (41), and the heat roller (42) is a spherical structure; the flexible heat pipe (43) is connected between the heat recovery arm (41) and the compensation component (5).

7. The steel structure arc welding device according to claim 4, characterized in that: The compensation assembly (5) includes a compensation chamber (51), a compensation piston (52), a compensation spring (53) and a transmission member (54); the compensation chamber (51) is provided in the mounting arm (21); the compensation piston (52) is slidably mounted in the compensation chamber (51), and one end of the compensation piston (52) extends out of the compensation chamber (51); the compensation spring (53) is connected between the compensation piston (52) and the compensation chamber (51); and the transmission member (54) is connected to the end of the compensation piston (52) extending out of the compensation chamber (51).

8. The steel structure arc welding device according to claim 7, characterized in that: The transmission member (54) includes a rotation fulcrum (541) and a telescopic lever (542); the rotation fulcrum (541) is arranged in the mounting arm (21); the telescopic lever (542) is rotatably mounted on the rotation fulcrum (541), and one end of the telescopic lever (542) is connected to the compensation piston (52), and the other end is connected to the sliding block (23).

9. The steel structure arc welding device according to claim 7, characterized in that: The power generation module (35) is a semiconductor temperature difference power generation sheet, and both ends of the power generation module (35) are respectively connected to the coolant flow channel (33) and the compensation cavity (51) through copper sheets.

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