An electric arc welding device for steel structures

Abstract

The present application relates to the technical field of welding manufacturing, in particular to a steel structure arc welding device, which comprises a clamping arm, a cold conduction assembly, a hot conduction assembly and a compensation assembly; the clamping arm is connected with the lower part of a welding arm; the cold conduction assembly is connected with the clamping arm, the hot conduction assembly is connected with the upper part of the welding arm, and the compensation assembly is connected with the hot conduction assembly; the workpiece is clamped by the clamping arm, and the hot conduction assembly rolls and presses the weld seam to make the crystal grains reform during the welding process; the heat absorbed during the rolling process drives the compensation assembly to drive the workpiece to make a compensation displacement, thereby reducing the residual stress; meanwhile, the temperature difference formed between the hot conduction assembly and the cooling liquid by the heat absorbed is utilized to cool the base material in the mode of fast cooling first and slow cooling later and conduct to the weld seam section, so that the core residual stress caused by the temperature gradient is avoided; the problem that the core position has a large residual stress caused by the different cooling speeds of the weld seam surface and the core during the welding of the large-thickness steel structure is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of welding manufacturing, in particular to a steel structure arc welding device. BACKGROUND

[0002] The arc welding equipment mainly converts the power grid power with high voltage and low current into welding power with low voltage and large current, and generates a high-temperature arc between the welding material and the steel structure workpiece through the current. The extremely high temperature of the arc can instantly melt the welding material and the workpiece, thereby forming a liquid molten pool, and as the welding gun moves, the molten pool will cool and solidify to achieve permanent metallurgical bonding between the steel materials.

[0003] Due to the high energy concentration of arc welding, the metal at the weld position can be heated to a molten state within a few seconds. The metal at the weld position will expand due to heating, but the surrounding base material is still at a low temperature, which will prevent the hot zone metal from expanding freely. At this time, the hot zone metal will be under compression stress, and the local temperature will drop to the yield strength of the material, or even to the temperature at which it enters the plastic state, which will cause plastic deformation under compression stress. When the welding heat source moves away, the shrinkage amount will change during the cooling and shrinkage process due to the previous plastic deformation, thereby causing the generation of residual stress. The prior art proposes a method for suppressing the generation of arc welding residual stress, such as patent CN113210799B, a welding residual stress control method and device based on longitudinal cyclic load. A stretching device is used to apply a longitudinal cyclic load to the workpiece to be welded, so that the workpiece produces a preset elastic deformation, and welding is performed in the state of the preset elastic deformation. After welding is completed, the longitudinal cyclic load is maintained for a preset time, and the preset longitudinal cyclic load is removed after the preset time. The rebound of the preset elastic deformation is used to offset the shrinkage deformation generated during the cooling process of the weld. However, there are still the following problems: when welding large and complex steel structures, due to the high stiffness and large thickness of the workpiece itself, the heat transfer in the thickness direction during welding is not uniform, resulting in a large temperature gradient between the surface and the core, and the cooling speed of the weld surface will be faster than that of the core. Therefore, during the cooling process, the surface weld will be cooled and will form the same constraint as the base material in the thickness direction, causing residual stress in the core at multiple angles. The peak value of this welding residual stress will be much higher than that of the surface, and for large-thickness steel structures, their own rigidity is high and it is difficult to release the stress through overall deformation. At the same time, the difference in cooling speed between the core and the surface will produce a very complex stress field in terms of size and distribution, therefore, it is not possible to simply apply a rebound force to effectively solve the residual stress generated by this complex temperature gradient.

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

[0005] The application provides a steel structure arc welding device, which solves the problem of large residual stress in the core position caused by different cooling speeds of the weld surface and the core during welding of a large-thickness steel structure, plastic deformation of a high-temperature austenite zone is caused by rolling of a hot roller over the uncooled weld surface during welding, dynamic recrystallization is triggered, weld performance is improved, a small part of heat energy is recovered to drive the workpiece to perform a compensation displacement, residual stress is reduced, and a temperature difference is generated between the recovered heat energy and a cooling liquid channel to generate electricity, the flow speed of the cooling liquid in the upper clamping plate and the lower clamping plate is controlled in real time by using the temperature difference change to cool the base material, thereby realizing forced cooling in a high-temperature state, slowing down the cooling speed in a medium-low temperature state, avoiding a large temperature gradient in the weld section, and further reducing residual stress.

[0006] To achieve the above object, the application provides the following technical scheme:

[0007] The application provides a steel structure arc welding device, which solves the problem of large residual stress in the core position caused by different cooling speeds of the weld surface and the core during welding of a large-thickness steel structure, plastic deformation of a high-temperature austenite zone is caused by rolling of a hot roller over the uncooled weld surface during welding, dynamic recrystallization is triggered, weld performance is improved, a small part of heat energy is recovered to drive the workpiece to perform a compensation displacement, residual stress is reduced, and a temperature difference is generated between the recovered heat energy and a cooling liquid channel to generate electricity, the flow speed of the cooling liquid in the upper clamping plate and the lower clamping plate is controlled in real time by using the temperature difference change to cool the base material, thereby realizing forced cooling in a high-temperature state, slowing down the cooling speed in a medium-low temperature state, avoiding a large temperature gradient in the weld section, and further reducing residual stress.

[0008] Preferably, the clamping arm comprises 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 with the lower part of the welding arm; the sliding seat is connected with the mounting arm; the sliding block is slidingly installed on the sliding seat; the upper clamping plate is slidingly installed on the sliding block; the lower clamping plate is fixedly installed on the sliding block; and the adjusting piece is connected with the upper clamping plate.

[0009] In the above scheme, the steel structure workpiece to be welded is clamped and fixed by the upper clamping plate and the lower clamping plate before welding, the freedom of the workpiece in other directions can be fixed by a welding table or a welding clamp, the freedom of the workpiece in the left and right directions is limited by the welding clamp during welding, the upper clamping plate and the lower clamping plate will limit the freedom of the workpiece in the vertical direction, and the movement of the workpiece in the front and back directions is synchronized with the upper clamping plate and the lower clamping plate, the upper clamping plate and the lower clamping plate will not move when compensation is not needed, and the upper clamping plate and the lower clamping plate will drive the workpiece to move in the micron level to perform compensation when compensation is needed, so that the residual stress is reduced.

[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, the hot roller will roll over the weld surface according to the moving path of the welding head after a delay, on the one hand, the hot roller will make the high-temperature austenite zone plastically deform, initiate dynamic recrystallization, so that the coarse and strong directional as-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, the tiny pores and shrinkage defects generated during welding can be eliminated, and stress concentration can be reduced; on the other hand, the hot roller will absorb part of the heat and conduct the absorbed heat to the compensation assembly through the flexible heat pipe.

[0018] Preferably, the compensation assembly comprises a compensation cavity, a compensation piston, a compensation spring and a transmission member; the compensation cavity is arranged in the mounting arm, and the compensation cavity is sealed and filled with a thermal expansion medium; the compensation piston is slidingly arranged in the compensation cavity, and one end of the compensation piston extends out of the compensation cavity; the compensation spring is connected between the compensation piston and the compensation cavity; and the transmission member is connected to the end of the compensation piston extending out of the compensation cavity.

[0019] In the above scheme, the flexible heat pipe transmits the recovered heat to the thermal expansion medium in the compensation cavity (considering the material / total volume), and the thermal expansion medium expands by recovering the heat, thereby pushing the compensation piston to slide, and the transmission member is driven to rotate by the sliding movement of the compensation piston.

[0020] Preferably, the transmission member comprises a rotation fulcrum and an extension lever; the rotation fulcrum is arranged in the mounting arm; and the extension lever is rotatably arranged on the rotation fulcrum, and one end of the extension lever is connected to the compensation piston, and the other end of the extension lever is connected to the sliding block.

[0021] In the above scheme, the sliding block can be moved when the compensation piston pushes the extension lever to move, thereby driving the upper clamping plate and the lower clamping plate to move the workpiece, and the displacement of the workpiece can be greatly reduced by adjusting the position of the fulcrum, and the pushing force of the compensation piston can be further increased due to the longer force arm from the fulcrum to the end of the compensation piston, thereby helping to improve the compensation force applied to the workpiece.

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

[0023] In the above scheme, cold and heat energy are conducted to the two ends of the power generation module through copper sheets, creating a temperature difference between the two ends of the power generation module. This generates electricity to drive the coolant pump to rotate, accelerating the circulation speed of the coolant. The greater the temperature difference, the greater the power generation, which in turn makes the coolant pump rotate faster, increasing the flow rate of the coolant and ensuring that peak heat can be removed. Although a fast cooling rate can refine the grains to the maximum extent, if the cooling rate exceeds the critical cooling rate, the austenite will not be able to transform into ferrite and pearlite, but will instead transform into high-hardness, 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 achieving a cooling scheme that is fast at first and then slows down in accordance with the temperature change of the weld.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. Compared to existing automatic arc welding equipment, this invention uses a circulating coolant within the upper and lower clamping plates holding the base material to cool it down. This transforms the heat loss from the upper and lower surfaces to the air at the weld location into lateral cooling by the base material, resulting in more synchronized and uniform cooling of the entire weld cross-section. This significantly reduces the difference in cooling rates between the weld surface and the core. Compared to slow air cooling, this forced cooling method can suppress grain coarsening, thereby improving the strength and toughness of the weld. Furthermore, during the welding process, the hot rollers moving along the same path as the welding arm roll the weld, forcing plastic deformation in the high-temperature austenite region and inducing dynamic recrystallization. This causes the coarse, highly directional cast columnar crystals to be broken down under the rolling pressure, and then re-nucleated and grown into fine, uniform equiaxed crystals, thereby improving weld performance. At the same time, it can eliminate micro-porosity and shrinkage defects generated during the welding process, reduce stress concentration, and further improve weld performance.

[0026] 2. This invention recovers a small portion of the heat from the weld by using a hot roller. This heat will cause the thermal expansion medium in the compensation chamber to expand, thereby pushing the compensation piston to slide. The sliding motion of the compensation piston will then drive the telescopic lever to slide the upper and lower clamping plates. Under the conditions of the limit component and the lever arm length settings at both ends, the upper and lower clamping plates will drive the workpiece to perform micron-level dynamic displacement compensation, thereby relieving the tensile force generated by the base material on the weld during the solidification stage, preventing the generation of hot cracks, and significantly reducing the residual stress peak.

[0027] 3. The application controls the rotating speed of the cooling liquid pump by setting the power generation module of the temperature difference power generation, heats one end of the power generation module by the heat recovered by the heat roller, cools the other end of the power generation module by the cooling liquid in the cooling liquid channel, so as to generate the temperature difference, and the temperature difference will automatically change according to the change of the welding seam temperature, and then the flow speed of the cooling liquid is slowed down when the temperature difference is reduced, so as to reduce the cooling speed of the welding seam, so that the cooling process of the welding seam is fast first and slow later, the welding seam is quickly cooled at high temperature, the austenite grain is inhibited from increasing, the desired structure is obtained at the intermediate temperature with moderate cooling speed, the martensite is avoided from being generated, the hydrogen atom is slowly cooled at the last low temperature, the cold crack is prevented from being generated, and the residual stress is released to a certain extent. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the specific embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

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

[0030] Figure 2 It is the internal structure schematic diagram of the mounting arm of the present application;

[0031] Figure 3 It is Figure 2 the structure enlarged view of A in the figure;

[0032] Figure 4 It is the structure schematic diagram of the clamping arm of the present application;

[0033] Figure 5 It is the connection relationship schematic diagram of the transmission member and the sliding block of the present application;

[0034] Figure 6 It is Figure 2 the structure enlarged view of B in the figure;

[0035] Figure 7 It is the internal structure sectional view of the compensation cavity of the present application;

[0036] Figure 8 It is Figure 7 the structure enlarged view of C in the figure.

[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 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 with the lower part of the welding arm 1; the sliding seat 22 is connected with the mounting arm 21; the sliding block 23 is slidingly installed on the sliding seat 22; the upper clamping plate 24 is slidingly installed on the sliding block 23; the lower clamping plate 25 is fixedly installed on the sliding block 23; and the adjusting member 26 is connected with the upper clamping plate 24. Before welding, the upper clamping plate 24 and the lower clamping plate 25 are used to clamp and fix the steel structure workpiece to be welded, and then the other degrees of freedom of the workpiece can be fixed by a welding table or a welding clamp. During the welding process, the degrees of freedom of the workpiece in the left and right directions are limited by the welding clamp, the upper clamping plate 24 and the lower clamping plate 25 limit the degree of freedom of the workpiece in the vertical direction, and the movement of the workpiece in the front and back directions is synchronized with the upper clamping plate 24 and the lower clamping plate 25. When compensation is not needed, the upper clamping plate 24 and the lower clamping plate 25 will not move, and when compensation is needed, the upper clamping plate 24 and the lower clamping plate 25 will drive the workpiece to move in the micron level for compensation, thereby reducing the residual stress.

[0042] As a specific embodiment of the present application, refer to Figure 3 and Figure 4 The sliding seat 22 is provided with a limiting member 221 on both sides; the adjusting member 26 comprises 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; the adjusting screw hole 262 is formed in the sliding block 23; and the adjusting bolt 263 is installed in the adjusting screw hole 262. The limiting member 221 here 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 in advance according to the welding process and welding material, and when the maximum displacement compensation is reached, it cannot continue to move, thereby eliminating the generation of excessive compensation. Even if the pressure generated by the heat conduction assembly 4 and the compensation assembly 5 continues to rise, the excess force will act on the limiting member 221 and the fixed rack of the welding arm 1. For example, for the welding of two 20mm thick Q345 steel plates, the heat shrinkage will cause the required compensation displacement to be usually in the range of 100 to 300μm during cooling from 800℃ to room temperature. Before welding, the operator can set the limiting member 221 to allow displacement within this range.

[0043] As a specific embodiment of the present application, refer to Figure 4 , Figure 5 and Figure 8The cold conduction assembly 3 comprises a cooling liquid cavity 31, a communication pipeline 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 arranged in the upper clamping plate 24 and the lower clamping plate 25. The communication pipeline 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 with 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. The liquid outlet pipe 37 is connected with the lower clamping plate 25. The cooling liquid flow channel 33 is externally connected with a cooling liquid storage container through a hose. The cooling liquid pump 34 rotates to guide the cooling liquid into the cooling liquid cavity 31 of the upper clamping plate 24 and the lower clamping plate 25, so that the cooling liquid can cool the steel structure base material part to be welded. At this time, the heat is dissipated to the air from the upper and lower surfaces to become transverse cooling of the base material, so that the cooling of the entire weld cross section is more synchronized and uniform, the cooling speed difference between the weld surface and the core is greatly reduced, and compared with air slow cooling, this forced cooling mode 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. The liquid outlet pipe 37 is externally connected with a cooling liquid recovery container, and the cooling liquid after being heated can be cooled again and guided back to the cooling liquid storage container, so as to be recycled. The communication pipeline 32 is a sealed telescopic structure. The telescopic communication pipeline 32 can make the cooling liquid flow between the upper clamping plate 24 and the lower clamping plate 25 intercommunicate, and can ensure that the distance between the upper clamping plate 24 and the lower clamping plate 25 is adjusted without affecting the flow path of the cooling liquid, while improving the stability between the upper clamping plate 24 and the lower clamping plate 25.

[0044] As a specific embodiment of the present application, reference is made to Figure 2 , Figure 6 and Figure 7The heat transfer assembly 4 comprises a heat recovery arm 41, a heat roller 42 and a flexible heat pipe 43; the heat recovery arm 41 is connected with the upper part of the welding arm 1 and is made of a material with high thermal conductivity; the heat roller 42 is rollingly installed at the end position of the heat recovery arm 41 and is in a spherical structure and made of a material with high thermal conductivity; the flexible heat pipe 43 is connected between the heat recovery arm 41 and the compensation assembly 5, is a high-temperature sodium-based or potassium-based heat pipe, adopts a sintered metal powder core structure and can operate efficiently at a heat end temperature of up to 900℃, is connected with the heat recovery arm 41 through a silver brazing copper saddle and is connected with the compensation cavity 51 through a heat-conducting high-pressure flange to ensure that the best heat flow enters the heat expansion medium. During the movement of the welding arm 1 to drive the welding head, the heat roller 42 will roll over the weld surface after a delay for a period of time according to the movement path of the welding head, on the one hand, the heat roller 42 will cause plastic deformation of the high-temperature austenite zone, initiate dynamic recrystallization, make the coarse and directional as-cast columnar crystals be broken under the action of the rolling pressure and be nucleated and grown again to form fine and uniform equiaxed crystals, thereby improving the weld performance and eliminating the tiny pores and shrinkage defects generated during the welding process and reducing stress concentration; on the other hand, the heat roller 42 will absorb part of the heat and conduct the absorbed heat to the compensation assembly 5 through the flexible heat pipe 43; 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 heat roller 42 rolling the weld relative to the start of the welding, and the welding arm 1 is automatically welded under the program intelligent control, can be set to continue to move after the welding of the welding arm 1 is completed (and the movement path of the heat roller 42 is completely same as the movement path of the welding head on the welding arm 1), and stops moving until the heat roller 42 rolls over all the welds; the welding arm 1 uses an automatic or semi-automatic arc welding structure and uses an automatic wire feeding system, so that the welding torch does not need to be moved downward after the welding material is shortened, and therefore the heat roller 42 does not need to be moved downward synchronously.

[0045] As a specific embodiment of the present application, reference is made to Figure 7The compensation assembly 5 comprises a compensation cavity 51, a compensation piston 52, a compensation spring 53 and a transmission member 54; the compensation cavity 51 is arranged in the mounting arm 21; the compensation piston 52 is slidingly arranged in the compensation cavity 51 and extends out of the compensation cavity 51 at one end; the compensation spring 53 is connected between the compensation piston 52 and the compensation cavity 51; and the transmission member 54 is connected to the end of the compensation piston 52 extending out of the compensation cavity 51. The flexible heat pipe 43 transfers the recovered heat to the thermal expansion medium (considering the material / total volume) in the compensation cavity 51, and the thermal expansion medium is expanded by the recovered heat, thereby pushing the compensation piston 52 to slide, and the sliding movement of the compensation piston 52 drives the transmission member 54 to rotate. The thermal expansion medium can be R-1233zd or R-245fa, both of which have good pressure-temperature curves and suitable pressure ranges for hydraulic elements, and will not cause corrosion to commonly used metal materials. R-1233zd can be boiled at 40-50 DEG C and can generate a driving force of 10-15 atm at about 150 DEG C. The cross-sectional size of the compensation cavity 51 and the compensation piston 52 can be designed according to the size and weight of the steel structure to be welded. For R-1233zd, about 10 Bar of pressure is generated at about 150 DEG C, and about 1 ton of thrust is generated at a cross section with a radius of 5 cm. Through displacement compensation, the tensile force generated by the base material on the weld during the cooling and solidification process can be reduced, the generation of thermal cracks can be prevented, and the residual stress peak value can be greatly reduced. Since the compensation piston 52 can be pushed to the farthest end by the thermal expansion medium at 150 DEG C, the weld can be hardened and solidified when cooled to below 500 DEG C, so that even if the thermal expansion medium is cooled to the shrinkage state subsequently, the compensation piston 52 will not retreat.

[0046] As a specific embodiment of the present application, referring to Figure 5 and Figure 7 The transmission member 54 comprises a rotating pivot point 541 and an extension lever 542; the rotating pivot point 541 is arranged in the mounting arm 21; the extension lever 542 is rotatably arranged on the rotating pivot point 541, and one end of the extension lever 542 is connected to the compensation piston 52 and the other end is connected to the sliding block 23. When the compensation piston 52 pushes the extension lever 542 to move, the sliding block 23 is driven to move, thereby driving the upper clamping plate 24 and the lower clamping plate 25 to drive the workpiece to move, the two ends of the extension lever 542 are arranged in an extendable structure, so that movement interference is avoided, the displacement of the workpiece can be greatly reduced by adjusting the position of the pivot point (i.e. adjusting the ratio of the two force arms), and the pushing force of the compensation piston 52 can be further increased due to the longer force arm from the pivot point to one end of the compensation piston 52, thereby helping to improve the compensation force applied to the workpiece.

[0047] As a specific embodiment of the present application, referring to Figure 7And Figure 8 The power generation module 35 is a semiconductor thermoelectric power generation sheet, and the two ends of the power generation module 35 are connected with the cooling liquid flow channel 33 and the compensation cavity 51 respectively through copper sheets. The cooling liquid is selected to be deionized water special insulating cooling liquid, and the thermal expansion medium R-1233zd is an insulating medium, so that the copper sheets will not cause short circuit and leakage phenomenon when directly contacting with the two kinds of media. After the copper sheets are inserted, the sealing property of the original compensation cavity 51 and the cooling liquid flow channel 33 should be ensured not to be damaged, and welding or a sealing element capable of bearing corresponding temperature and pressure can be considered. The cold energy and the heat energy are respectively conducted to the two ends of the power generation module 35 through the copper sheets, so that the temperature difference is generated at the two ends of the power generation module 35, thereby generating electric energy to drive the cooling liquid pump 34 to rotate (in order to ensure the normal work of the cooling liquid pump 34 and simultaneously have a self-adaptive speed regulation function, a boost-voltage stabilizing module with a maximum power point tracking function can be added). The circulation speed of the cooling liquid is accelerated, and the greater the temperature difference is, the greater the power generation will be, so that the rotating speed of the cooling liquid pump 34 is faster, the flow speed of the cooling liquid is improved, and it is ensured that the peak heat can be taken away. Although the cooling speed is fast, the grain can be refined to the maximum extent, but if the cooling speed exceeds the critical cooling speed, the austenite cannot be converted into ferrite and pearlite, but is converted into martensite with high hardness and low plasticity. Through the power generation module 35, the flow speed of the cooling liquid can be slowed down in the subsequent cooling process as the temperature difference decreases, so that the cooling scheme of fast cooling at high temperature (greater than 800 DEG C) and slow cooling at low temperature (less than 500 DEG C) is realized according to the temperature change of the weld. In the high temperature (greater than 800 DEG C), the austenite grain is inhibited from growing, in the intermediate temperature (500 to 800 DEG C), the desired structure (ferrite + pearlite, or bainite) is obtained at a moderate cooling speed, the martensite is avoided, and finally in the low temperature (less than 500 DEG C), the hydrogen atoms in the steel structure have enough time and energy to diffuse from the weld, thereby reducing the risk of cold cracking. When the temperature is between 300 DEG C and 500 DEG C, the steel still has a certain creep and plastic deformation ability, and slow cooling in this state can release the residual stress to a certain extent.

[0048] Work flow: Before welding, the maximum compensation displacement is set according to the workpiece to be welded, the maximum displacement that the limiting part 221 can generate to the sliding block 23 is limited, the workpiece is limited by the welding table or the welding clamp, the freedom of the workpiece in the non-compensation direction is limited, the upper clamping plate 24 is adjusted by screwing the adjusting bolt 263, the upper clamping plate 24 and the lower clamping plate 25 clamp the workpiece, the cooling liquid flow channel 33 is connected with the low-temperature cooling liquid storage container through the hose, and the liquid outlet pipe 37 is connected with the cooling liquid recovery container.

[0049] After the welding preparation work is completed, the welding is started, the welding arm 1 is controlled by the automatic program to move along the preset path, and the hot roller 42 will roll on the weld surface after a delay according to the movement path of the welding head, so that the high-temperature austenite zone is plastically deformed, dynamic recrystallization is induced, and the weld performance is improved. At the same time, when the hot roller 42 rolls on the weld surface, it will absorb part of the heat, 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 drive the compensation piston 52 to slide, the compensation piston 52 slides to drive the telescopic lever 542 to rotate around the rotating support point 541, and the telescopic lever 542 drives the workpiece clamped by the upper clamping plate 24 and the lower clamping plate 25 to move by microns, which greatly reduces the residual stress peak value; At the same time of temperature rise of the thermal expansion medium, since the two ends of the power generation module 35 are connected with the cooling liquid flow channel 33 and the compensation cavity 51 through copper sheets respectively, at this time the two ends of the power generation module 35 will generate a large temperature difference, thereby generating electric energy to drive the cooling liquid pump 34 to rotate, through the rotation of the cooling liquid pump 34, the cooling liquid can be pumped from the external low-temperature cooling liquid storage container to the cooling liquid cavity 31 of the upper clamping plate 24 and the lower clamping plate 25, and after heat exchange with the base material, it is recovered to the external cooling liquid recovery container through the liquid outlet pipe 37, and as the temperature difference between the two ends of the power generation module 35 increases, the power generation will be greater, so that the rotating speed of the cooling liquid pump 34 is faster, the flow speed of the cooling liquid is improved, and it is ensured that the peak heat can be taken away, and in the subsequent cooling process, as the temperature difference decreases, the flow speed of the cooling liquid will be slowed down, so that the residual stress can be released to a certain extent.

[0050] The basic principles, main features and advantages of the present application are shown and described above. Those skilled in the art should understand that the present application is not limited to the above-mentioned embodiments, and the above-mentioned embodiments and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A steel construction electric arc welding device comprising a welding arm (1), characterized in that: It also includes clamping arm (2), cold conduction assembly (3), heat conduction assembly (4) and 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 with the welding arm (1) during the movement of the welding arm (1) along the preset welding path, absorbs the heat of the weld during the movement of the heat conduction assembly (4), 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 the movement of the heat conduction assembly (4) with the welding arm (1).

2. An electric arc welding apparatus for steel structures as claimed in claim 1, characterized in that: The clamping arm (2) includes mounting arm (21), sliding seat (22), sliding block (23), upper clamping plate (24), lower clamping plate (25) and adjusting part (26); the mounting arm (21) is connected with the lower part of the welding arm (1); the sliding seat (22) is connected with the mounting arm (21); the sliding block (23) is slidingly installed on the sliding seat (22); the upper clamping plate (24) is slidingly installed on the sliding block (23); the lower clamping plate (25) is fixedly installed on the sliding block (23); the adjusting part (26) is connected with the upper clamping plate (24).

3. A steel construction electric arc welding device according to claim 2, characterized in that: The sliding seat (22) is provided with limit pieces (221) on both sides; the adjusting part (26) includes tension spring (261), adjusting screw hole (262) and adjusting bolt (263); the tension spring (261) is connected between the upper clamping plate (24) and the sliding block (23); the adjusting screw hole (262) is formed in the sliding block (23); the adjusting bolt (263) is installed on the adjusting screw hole (262).

4. A steel construction electric arc welding device according to claim 2, characterized in that: The cold conduction assembly (3) includes cooling liquid cavity (31), communication pipeline (32), cooling liquid flow channel (33), cooling liquid pump (34), power generation module (35), liquid inlet pipe (36) and liquid outlet pipe (37); the cooling liquid cavity (31) is formed in the upper clamping plate (24) and the lower clamping plate (25); the communication pipeline (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 with 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); the liquid outlet pipe (37) is connected with the lower clamping plate (25).

5. A steelwork electric arc welding apparatus according to claim 4, characterised in that: The communication pipeline (32) is a sealed telescopic structure.

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

7. A steel construction electric arc welding device according to claim 4, characterized in that: The compensation assembly (5) comprises a compensation cavity (51), a compensation piston (52), a compensation spring (53) and a transmission member (54); the compensation cavity (51) is arranged in the mounting arm (21); the compensation piston (52) is slidingly installed in the compensation cavity (51), and one end of the compensation piston (52) extends out of the compensation cavity (51); the compensation spring (53) is connected between the compensation piston (52) and the compensation cavity (51); and the transmission member (54) is connected with the end of the compensation piston (52) extending out of the compensation cavity (51).

8. A steel construction electric arc welding device according to claim 7, characterized in that: The transmission member (54) comprises a rotating support point (541) and an extension lever (542); the rotating support point (541) is arranged in the mounting arm (21); and the extension lever (542) is rotatably installed on the rotating support point (541), and one end of the extension lever (542) is connected with the compensation piston (52), and the other end is connected with the sliding block (23).

9. A steel construction electric arc welding device according to claim 7, characterized in that: The power generation module (35) is a semiconductor thermoelectric power generation sheet, and two ends of the power generation module (35) are connected with the cooling liquid flow channel (33) and the compensation cavity (51) respectively through copper sheets.

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