Steel structure electric arc welding equipment for building construction

Abstract

The invention relates to the technical field of building construction welding, in particular to steel structure electric arc welding equipment for building construction. The device comprises a welding gun, a nozzle structure is installed at the bottom of a welding head connecting pipe in a threaded mode, the nozzle structure comprises a hollow spraying pipe and a contact tube extending from the interior of the welding head connecting pipe, an isolation inner pipe is installed in the spraying pipe in a clamped mode, and a gas flow channel formed between the spraying pipe and the contact tube is separated through the isolation inner pipe. The external expansion structure at the lower end of the isolation inner pipe is matched with the height difference between the bottom end of the isolation inner pipe and the bottom end of the spray pipe, physical shielding is formed, and high-temperature splashes entering the external sub-runner during welding are reduced; therefore, adhesion on the inner wall of the outer sub-runner is effectively avoided, the outer sub-runner is kept smooth all the time, and stable conveying of the protective gas is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of welding technology in building construction, and more specifically, to an arc welding device for steel structures used in building construction. Background Technology

[0002] In the field of building construction, the connection quality of steel structures is directly related to the stability and safety of the overall structure. Semi-automatic carbon dioxide gas shielded arc welding has become a commonly used on-site welding technology due to its high efficiency and moderate cost.

[0003] However, during the welding process of steel structures, the large amount of spatter generated by welding easily adheres to the inner wall of the welding torch nozzle. This not only blocks the channel for delivering shielding gas, leading to the failure of the molten pool protection (causing defects such as porosity and slag inclusions), but also requires frequent shutdowns for cleaning, seriously affecting construction efficiency. The defects caused by these spatters directly weaken the mechanical properties of the steel structure welds: porosity reduces the effective load-bearing area of ​​the weld, making the connection prone to stress concentration when under stress, thus reducing the overall load-bearing capacity of the structure; slag inclusions disrupt the continuity of the weld, leading to a decrease in weld strength, and may even cause crack propagation under vibration, impact, and other conditions, threatening structural safety.

[0004] Meanwhile, the conductive tip in the welding torch nozzle is in direct contact with the high-temperature electric arc, which frequently causes overheating problems, easily leading to wire sticking and wire feeding interruption. This forces the welding process to be interrupted, and when the arc is restarted, defects such as incomplete fusion and incomplete penetration are likely to occur. When the steel structure is subjected to its own weight, load or external environmental action, these defects are very likely to become sources of stress concentration, leading to connection failure and reducing the reliability of the steel structure connection.

[0005] Therefore, there is an urgent need for an electric arc welding equipment for steel structures in building construction to solve the above problems. Summary of the Invention

[0006] This invention provides an electric arc welding device for steel structures in building construction. It uses an inner isolation pipe to divert the shielding gas, creating a rotating shielding gas curtain in the outer distribution channel to isolate air. The inner distribution channel generates a high-speed airflow to cool the conductive nozzle, achieving stable arc and ensuring weld pool quality during steel structure welding. This provides efficient and high-quality welding operations, thereby solving the problems mentioned in the background art.

[0007] Spatter during welding can clog the welding channel, leading to defects in the molten pool and weakening the weld performance. Overheating of the contact tip can cause welding interruptions and defects, reducing the reliability of the steel structure.

[0008] To achieve the above objectives, the arc welding equipment includes a welding torch, which consists of a front tube and a rear tube.

[0009] Welding torch front tube: includes wire feed guide and shielding gas channel, the wire feed guide is used to continuously feed the welding wire; welding head connecting tube, which is sealed to the wire feed guide and shielding gas channel, and has a nozzle structure installed at its bottom thread;

[0010] The nozzle structure includes a hollow nozzle and a conductive nozzle extending from the inside of the welding head connecting pipe. The conductive nozzle is centered inside the nozzle, and the welding wire is located inside the conductive nozzle. A ceramic insulating inner tube is snapped into the inside of the nozzle, and the insulating inner tube separates the gas flow channel formed between the nozzle and the conductive nozzle.

[0011] The lower end of the inner tube extends into a nozzle and is flared outwards. This physical shielding reduces the amount of high-temperature spatter entering the outer gas channel during welding. The inner gas channel leads directly to the outer wall of the contact tip, specifically guiding the protective gas to the outlet area of ​​the welding wire, enhancing the protection effect of the molten pool. At the same time, the high-speed airflow passes over the surface of the contact tip, providing targeted cooling.

[0012] In the above technical solution, the inner tube made of ceramic material forms a dual-path delivery structure by separating the gas flow channel between the nozzle and the conductive nozzle. The outer path forms a protective air curtain, while the inner path leads directly to the outer wall of the conductive nozzle. The two paths work together to reduce the blockage caused by high-temperature splashes entering the gas flow channel through the physical shielding of the outward-expanding structure at the lower end of the inner tube, and to achieve efficient cooling by utilizing the airflow of the inner path to flow specifically over the surface of the conductive nozzle.

[0013] Based on this, the lower opening of the outer diversion channel is smaller than the lower opening of the inner diversion channel. The outer wall of the isolation inner tube and the inner wall of the nozzle are both provided with spiral grooves. The two spiral grooves cooperate with each other to form a spiral channel for the outer diversion channel.

[0014] The spiral channel formed by the inner isolation tube and the spiral groove on the inner wall of the nozzle makes the gas flow velocity in the outer diversion channel higher and rotate, which enhances the air curtain's tightness and coverage to isolate air. The inner diversion channel covers the welding wire area with a gentle airflow, which strengthens the protection of the molten pool and avoids airflow disturbance, further improving the stability of welding quality.

[0015] Furthermore, a connecting gasket is fixedly installed on the outer wall of the mounting plate, and an inner connecting groove is opened at the upper end of the inner cavity of the nozzle. The connecting gasket is fastened to the inside of the inner connecting groove to realize the installation and fixation of the isolation inner tube. Specifically, this fastening structure can quickly realize the installation and removal of the isolation inner tube, facilitate the cleaning of splashes adhering to the surface of the outer expansion structure, and at the same time ensure the stability of the isolation inner tube during operation, maintaining the gas diversion and splash shielding effect.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] By using the outward expansion structure at the lower end of the isolation inner tube, combined with the height difference between its bottom end and the bottom end of the nozzle, a physical shield is formed, reducing the amount of high-temperature spatter entering the outer distribution channel during welding. At the same time, the outer distribution channel is formed by the spiral grooves of the isolation inner tube and the inner wall of the nozzle, which together form a spiral channel. Even if a small amount of spatter falls, it will be carried out by the inclined guidance of the spiral channel and the gas flow, effectively preventing it from adhering to the inner wall of the outer distribution channel, ensuring that it always remains unobstructed, and guaranteeing the stable delivery of protective gas.

[0018] The spiral channel design allows the protective gas delivered by the outer channel to form a rotating airflow when ejected, expanding the coverage of the protective gas and enabling it to more comprehensively envelop the molten pool, thus increasing the protection effect on the welding area. In addition, the rotating airflow has a larger contact area with the base material and a faster flow speed. While delivering the protective gas, it can quickly remove some of the heat from the surface of the base material, helping to reduce the temperature of the welding area and reduce changes in the properties of the base material caused by local overheating.

[0019] Due to the partition design of the inner tube, the inner diameter of the inner flow channel is narrower than that of the original gas flow channel, which increases the flow velocity of the protective gas flowing through this channel. The high-speed airflow directly acts on the outer wall of the contact tip, forming a targeted forced cooling effect, which can reduce the heat accumulation of the contact tip due to contact with the high-temperature electric arc and improve the stability of the welding process. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0021] Figure 2 This is a schematic diagram of the nozzle structure of the present invention;

[0022] Figure 3 This is a front sectional view of the nozzle of the present invention;

[0023] Figure 4 For the present invention Figure 3 A schematic diagram of the structure at point A;

[0024] Figure 5 This is a schematic diagram of the nozzle mounting structure of the present invention;

[0025] Figure 6 This is a schematic diagram of the installation structure of the isolation inner tube of the present invention;

[0026] Figure 7 This is a schematic diagram of the overall structure of the isolation inner tube of the present invention;

[0027] Figure 8 This is a schematic diagram of the gas flow channel splitting structure of the present invention;

[0028] Figure 9 This is a diagram showing the angle of the lower end of the isolation inner tube of the present invention.

[0029] Figure 10 This is a diagram showing the extension status of the lower end of the isolation inner tube according to the present invention.

[0030] The meanings of the labels in the diagram are as follows:

[0031] 1. Welding torch; 11. Welding torch front tube; 12. Welding torch rear tube;

[0032] 111. Wire feeding guide tube; 112. Shielding gas passage; 113. Welding head connecting tube; 114. Welding wire;

[0033] 121. Welding torch trigger; 122. Main piping; 123. Input interface structure;

[0034] 2. Nozzle structure; 21. Nozzle pipe; 22. Conductive nozzle; 23. Inner isolation tube; 24. Gas flow channel; 25. Mounting plate; 26. Outer outlet; 27. Inner outlet; 210. Inclination angle;

[0035] 241. External branch channel; 242. Internal branch channel;

[0036] 3. Inner connecting groove; 31. Connecting washer ring;

[0037] 4. Spiral groove; 41. Spiral channel. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] This invention provides an arc welding device for steel structures used in building construction. See [link to relevant documentation]. Figures 1-5 As shown, it includes a welding torch 1, which is composed of a welding torch front tube 11 and a welding torch rear tube 12; the welding torch front tube 11 includes a wire feeding guide tube 111 and a protective gas channel 112, and the wire feeding guide tube 111 is used to continuously feed the welding wire 114.

[0040] The welding head connecting tube 113 is sealed to the wire feeding guide tube 111 and the protective gas channel 112. A nozzle structure 2 is threaded on its bottom. The nozzle structure 2 includes a hollow nozzle 21 and a conductive nozzle 22 extending from the inside of the welding head connecting tube 113. The conductive nozzle 22 is centered inside the nozzle 21, and the welding wire 114 is located inside the conductive nozzle 22.

[0041] The nozzle 21 is fitted with a ceramic inner tube 23, which separates the gas flow channel 24 formed between the nozzle 21 and the conductive nozzle 22.

[0042] The lower end of the inner tube 23 extends outward from the nozzle 21, which is flared outward. This reduces the amount of high-temperature spatter entering the outer gas channel 24 during welding by physical shielding. The inner gas channel 24 leads directly to the outer wall of the contact nozzle 22, which specifically guides the protective gas to the outlet area of ​​the welding wire 114, thereby enhancing the protection effect of the molten pool. At the same time, the high-speed airflow passes over the surface of the contact nozzle 22, which can cool it at specific points.

[0043] When the welding gun 1 is in use, it needs to be connected to external electrical and material sources through the welding gun rear tube 12, and then transported through the welding gun front tube 11. The specific structure of the welding gun rear tube 12 is disclosed below. The welding gun rear tube 12 includes a welding gun trigger 121, a main pipe 122 and an input interface structure 123.

[0044] The main pipeline 122 integrates the conveying and protective gas transmission channels for the welding wire 114. One end of the channel is adapted and connected to the welding torch trigger 121, and the other end extends to the input interface structure 123. The input interface structure 123 is used to connect the protective gas source, welding wire 114 and power supply required for welding, so as to realize the docking of the external medium with the channel inside the main pipeline 122.

[0045] like Figure 3 As shown, the input interface structure 123 of the welding torch rear tube 12 includes a gas interface, a welding wire 114 interface, and an electrical interface (not shown in the figure). Specifically, the gas interface is connected to an external shielding gas source through a pipeline; the welding wire 114 interface is connected to the wire feeding mechanism of the external welding wire 114 reel; and the electrical interface is connected to the welding power source through a cable. The welding wire 114 conveying channel inside the main pipeline 122 is connected to the welding wire 114 interface of the input interface structure 123 to guide the external welding wire 114 to the wire feeding guide 111 of the welding torch front tube 11; and the shielding gas transmission channel is connected to the gas interface of the input interface structure 123 to guide the shielding gas to the welding torch front tube 11. The protective gas passage 112 of the front tube 11 and the electrical circuit in the main pipeline 122 are connected at one end to the electrical interface of the input interface structure 123, and at the other end to the welding torch trigger 121 to form a circuit with the conductive nozzle 22 of the front tube 11. The welding torch trigger 121 is equipped with a switch assembly. When the trigger is pressed, the switch assembly is closed, which makes the electrical circuit conductive. The welding power supply output current forms an arc with the welding wire 114 and the workpiece through the conductive nozzle 22. At the same time, it triggers the wire feeding mechanism and the gas source, so that the welding wire 114 is fed through the conveying channel and the protective gas is ejected through the transmission channel. When the trigger is released, the switch assembly is opened, the current is cut off, and the wire feeding and gas delivery stop synchronously.

[0046] The top of the isolation inner tube 23 is connected to the mounting plate 25. The surface of the mounting plate 25 has multiple annular channels. The outer annular channel is the outflow port 26, and the inner annular channel is the inflow port 27.

[0047] The isolation inner tube 23 divides the gas flow channel 24 into an outer branch channel 241 and an inner branch channel 242, and performs a diversion operation on the protective gas in the gas flow channel 24 by means of the outer outlet 26 and the inner outlet 27.

[0048] The mounting plate 25 at the top of the inner tube 23 is compatible with the inner diameter of the nozzle 21, allowing the mounting plate 25 to be installed inside the nozzle 21. Figure 7 and Figure 8 It can be seen that the surface of the mounting plate 25 is provided with an external outlet 26 and an internal outlet 27, and the external outlet 26 and the internal outlet 27 are connected to the gas flow channel 24 in the upper space of the nozzle 21.

[0049] When the external protective gas enters the gas flow channel 24 in the upper space of the nozzle 21 through the protective gas channel 112, it will enter the outer distribution channel 241 and the inner distribution channel 242 through the outer outlet 26 and the inner outlet 27 respectively, realizing the directional distribution of the protective gas. The protective gas is stably distributed to the two distribution channels according to the preset path, ensuring the uniformity of gas distribution. This allows the outer distribution channel 241 to obtain sufficient airflow to form an effective protective gas curtain (specifically, the protective gas ejected from the outer distribution channel 241 can form a protective gas curtain that wraps around the molten pool and the end of the welding wire 114 from the outside, blocking outside air from entering the welding area), and also allows the inner distribution channel 242 to obtain continuous airflow to cool the conductive nozzle 22, reducing the problem of insufficient protection effect or uneven heat dissipation caused by poor distribution.

[0050] The reason why the gas flow channel 24 is diverted by the isolation inner tube 23 to efficiently cool the conductive nozzle 22 is that the inner diversion channel 242 is formed by the inner wall of the isolation inner tube 23 and the outer wall of the conductive nozzle 22. Its spatial dimensions are narrower than the original gas flow channel 24. When the protective gas enters the inner diversion channel 242 through the inner inlet 27, the gas velocity increases due to the channel cross-section limitation, forming a continuous airflow that is faster than the flow velocity of the wide channel. The fast airflow flows directly over the outer wall surface of the conductive nozzle 22 and carries away the heat generated by the conductive nozzle 22 due to contact with the high-temperature electric arc through convection heat transfer. In addition, the annular design of the inner inlet 27 makes the gas evenly distributed around the circumference of the conductive nozzle 22 when it enters the inner diversion channel 242, so that the airflow can get closer to the surface of the conductive nozzle 22, thereby achieving cooling of the conductive nozzle 22.

[0051] The inner isolation tube 23 is made of zirconia-toughened alumina (ZTA) ceramic.

[0052] The lower opening of the outer branch channel 241 is smaller than the lower opening of the inner branch channel 242.

[0053] The lower end of the inner isolation tube 23 has an outward expansion structure that forms ∠a, and ∠a is 30°-45°.

[0054] Both the outer wall of the isolation inner tube 23 and the inner wall of the nozzle 21 are provided with spiral grooves 4. The two spiral grooves 4 cooperate with each other to form a spiral channel 41 in the outer diversion channel 241.

[0055] The improvements are: See Figure 4 As shown, the lower opening of the outer diversion channel 241 is formed by the outward expansion structure at the lower end of the isolation inner tube 23 and the inner wall of the nozzle 21. The lower opening of the inner diversion channel 242 is the gap between the inner wall of the isolation inner tube 23 and the outer wall of the conductive nozzle 22. Because the lower end of the isolation inner tube 23 is outwardly expanded, the size of the lower opening of the outer diversion channel 241 is smaller than the size of the lower opening of the inner diversion channel 242.

[0056] When the protective gas is ejected from the smaller opening of the outer branch channel 241, its flow velocity increases, while when it is ejected from the larger opening of the inner branch channel 242, its flow velocity is relatively low, creating a differentiated airflow distribution. The gas ejected from the outer branch channel 241 has more concentrated kinetic energy. Combined with the spiral channel 41 within the outer branch channel 241, the airflow inside the outer branch channel 241 exhibits rotating airflow characteristics, forming a dense protective gas curtain outside the molten pool, effectively isolating air. When the gas from the inner branch channel 242 is delivered to its outlet, it covers the end of the conductive tip 22 and the outlet of the welding wire 114 with a gentler flow velocity, reducing the disturbance of the molten pool by high-speed airflow. Simultaneously, the outward expansion angle of the outward expansion structure ( Figure 9 The angle ∠a) is set between 30° and 45° so that it neither excessively reduces the opening of the outer diversion channel 241 (avoiding excessive airflow resistance) nor fails to form sufficient physical shielding to reduce the amount of splashing material entering the outer diversion channel 241.

[0057] Based on gas flow characteristics, welding requirements, and structural interference limitations, the outward expansion angle of the lower end of the inner isolation tube 23 is set between 30° and 45°.

[0058] From the perspective of gas flow, the outward expansion angle directly affects the gas diffusion pattern at the outlet of the outer diversion channel 241. Through fluid dynamics simulation, it can be seen that when the angle is less than 30°, the diffusion angle after the gas is ejected is insufficient, the coverage of the protective gas curtain is limited, and it is difficult to completely wrap the molten pool and the end of the welding wire 114, which easily leads to the intrusion of external air. When the angle is greater than 45°, the gas diffuses too fast, and the density of the gas curtain will drop sharply with the diffusion distance, which will not form a sufficiently dense protective layer. Moreover, high-speed diffusion will cause airflow turbulence and may even entrain air.

[0059] From the perspective of spatter protection, if the spatter generated during the welding process enters the outer flow channel 241, it will cause blockage. The outward expansion structure needs to form a physical barrier. When the angle is less than 30°, the barrier height is insufficient, and the spatter can easily cross the structure and enter the flow channel. When the angle is greater than 45°, the lower end of the outward expansion structure is too close to the molten pool, and the spatter can easily adhere directly to the surface of the structure. Long-term accumulation will also hinder the airflow.

[0060] From the perspective of structural interference, the lower end of the isolation inner tube 23 needs to maintain a safe distance from the conductive nozzle 22 and the workpiece to avoid mechanical collision or arc interference during welding. Based on the dimensional parameters of conventional welding equipment (the extension length of the conventional conductive nozzle 22 and the diameter of the conventional nozzle 21), it is calculated that when the angle exceeds 45°, the outward expansion structure will significantly increase the radial dimension and is prone to interference with the workpiece or fixture; while when the angle is less than 30°, although there is no risk of interference, the gas diffusion effect will be sacrificed.

[0061] During the welding process of the welding torch 1 on the steel structure, the lower end of the inner isolation tube 23 expands outward to block spatter, allowing the protective gas to flow stably from the outer distribution channel 241. Over time, sticky spatter accumulates on the surface of the expanded structure. Therefore, the modular assembly structure of the inner isolation tube 23 facilitates the cleaning of this sticky spatter. Figure 6 and Figure 7 As shown, a connecting gasket 31 is fixedly installed on the outer wall of the mounting plate 25, and an inner connecting groove 3 is opened at the upper end of the inner cavity of the nozzle 21. The connecting gasket 31 is fastened to the inside of the inner connecting groove 3 to realize the installation and fixation of the inner tube 23.

[0062] The inner isolation tube 23 is fastened to the inner connecting groove 3 at the upper end of the nozzle 21 via an elastic connecting gasket 31 (made of nitrile rubber) fixed to the outer wall of the mounting plate 25, forming a modular assembly structure. The elastic material allows the connecting gasket 31 to deform during installation, solving the installation problem caused by its outer wall size being slightly larger than the inner wall of the nozzle 21, thus achieving a stable assembly. When spatter adheres to the surface of the lower end of the outer expansion structure of the inner isolation tube 23, it can be directly disassembled by external force, cleaned, and then reinstalled by fastening, ensuring that the inner isolation tube 23 continues to play its role in blocking spatter and diverting gas, maintaining welding stability.

[0063] It should be noted that the elastic connecting gasket 31 on the outer wall of the mounting plate 25 is fastened into the inner connecting groove 3 of the nozzle 21. After fastening, the elastic material will generate continuous radial pressure due to deformation, making the connecting gasket 31 tightly fit the inner wall of the inner connecting groove 3, forming a firm mechanical lock. At the same time, the outer wall of the mounting plate 25 and the inner wall of the nozzle 21 are adapted to each other, and their contact surfaces provide radial positioning for the inner isolation tube 23, limiting its lateral sway. In addition, when the inner isolation tube 23 is working, the outer diversion channel 241 and the inner diversion channel... The protective gas flow within 242 generates an upward lifting force (according to the momentum theorem in fluid mechanics, when a gas is constrained or guided by an object during its flow, and its direction or speed changes, it will generate a reaction force on that object), which balances with the weight of the inner isolation tube 23 itself, reducing the tendency for axial displacement. Through the combined action of these structures, the inner isolation tube 23 can maintain a stable position and will not loosen or shift under conditions such as vibration during welding, airflow impact, and collision with spatter.

[0064] The bottom end of the isolation inner tube 23 and the bottom end of the nozzle 21 form a height difference L, which is 5-15 mm.

[0065] The improvement lies in the fact that the bottom end of the isolation inner tube 23 and the bottom end of the nozzle 21 form a height difference L ( Figure 10 At point L in the diagram, the height difference L allows the outward expansion structure of the inner isolation tube 23 to more directly block the spatter generated during welding, reducing the probability of it entering the outer diversion channel 241. At the same time, the outlets of the outer diversion channel 241 and the inner diversion channel 242 form a step in the axial position. The gas in the outer diversion channel 241 contacts the welding area before the gas in the inner diversion channel 242, so that the protective gas curtain forms a wrapping from the outside first, and the inner diversion gas then supplements the coverage, improving the overall protection effect.

[0066] During the welding process of steel structures, the main spray range of welding spatter is concentrated in the area 5-30 mm above the molten pool. The outer expansion structure of the inner isolation tube 23 needs to extend into this area to effectively block the spatter. When L is less than 5 mm, the length of the outer expansion structure extending beyond the bottom of the nozzle 21 is insufficient, and the shielding area can only cover less than 30% of the spatter spray range, resulting in insufficient protection. When L reaches 5 mm, the shielding area is increased, and most of the spatter can be blocked.

[0067] From the perspective of gas protection effect, the protective gas ejected from the outer diversion channel 241 needs to form a stable gas curtain above the molten pool. Its effective working distance is usually 10-20 mm below the outlet of the nozzle 21. If L is greater than 15 mm, the outward expansion structure is too close to the molten pool, which will cause the gas in the outer diversion channel 241 to decrease in density due to the excessive diffusion distance before reaching the molten pool, thus weakening the gas curtain protection effect. However, when L is 5-15 mm, the gas can form a dense gas curtain within the effective working distance after being ejected, and the gas in the inner diversion channel 242 can supplement and cover it, forming a double layer of protection.

[0068] Therefore, 5-15 mm is the optimal range that simultaneously satisfies splash shielding efficiency, gas protection effect, structural safety, and operational flexibility.

[0069] Since the lower opening of the outer diversion channel 241 is smaller than the lower opening of the inner diversion channel 242, and the bottom of the nozzle 21 and the outward expansion structure of the isolation inner tube 23 form the end boundary of the outer diversion channel 241, the gas needs to pass through the narrow channel between the bottom of the nozzle 21 and the outward expansion structure of the isolation inner tube 23 when it flows out of the outer diversion channel 241. The flow resistance is easily generated due to the sudden change in the cross-section of the channel. Therefore, the bottom of the nozzle 21 is provided with an inclination angle 210. The inclination angle 210 is used to reduce the outlet resistance of the protective gas in the outer diversion channel 241.

[0070] See Figure 9As shown, the tilt angle 210 at the bottom of the nozzle 21 is located on the inner side of its lower end, corresponding to the end of the outer expansion structure of the inner isolation tube 23. When the protective gas flows downward along the outer diversion channel 241 to the end, the tilt angle 210 corrects the original right angle at the bottom of the nozzle 21 to a smooth slope, so that when the gas passes through the channel between the nozzle 21 and the outer expansion structure of the inner isolation tube 23, the flow path changes from abrupt to a smooth transition, reducing the eddy currents or airflow stagnation caused by boundary abrupt changes, and reducing energy loss during gas flow.

[0071] in, Figure 4 The diagram illustrates the welding process of the steel structure. Specifically, point e represents the electric arc formed by welding wire 114; point b represents the base material (steel structure); point c represents the molten pool produced by welding; and point d represents the weld produced by welding.

[0072] Working principle:

[0073] First, the external shielding gas source, welding wire 114, and welding power source are connected through the input interface structure 123 of the welding torch rear tube 12. The shielding gas enters the shielding gas transmission channel of the main pipeline 122 through the gas interface, and the welding wire 114 enters the welding wire 114 delivery channel through the welding wire 114 interface. The electrical circuit is connected to the welding power source through the electrical interface and extends to the welding torch trigger 121 and the conductive nozzle 22 of the welding torch front tube 11. When the welding torch trigger 121 is pressed, the switch assembly closes to conduct the electrical circuit. The welding power source output current forms an arc with the workpiece through the conductive nozzle 22 and the welding wire 114. At the same time, the wire feeding mechanism and the gas source are activated. The welding wire 114 is delivered to the inside of the conductive nozzle 22 through the wire feeding guide tube 111 and extends out. The shielding gas enters the gas flow channel 24 in the upper space of the nozzle 21 through the shielding gas channel 112 and the welding head connecting pipe 113.

[0074] The protective gas entering the gas flow channel 24 is split through the outflow port 26 and the inflow port 27 of the mounting plate 25 at the top of the inner isolation tube 23, and enters the outer flow channel 241 and the inner flow channel 242 respectively. The outer flow channel 241 is formed by the spiral groove 4 of the outer wall of the inner isolation tube 23 and the inner wall of the nozzle 21, forming a spiral channel 41. The gas forms a rotating airflow here and is ejected through the outlet with an optimized bottom inclination angle 210 of the nozzle 21. Due to the small opening at the lower end of the outer flow channel 241 and the guidance of the outward expansion structure at the lower end of the inner isolation tube 23, a dense protective gas curtain is formed on the outside of the molten pool. The inner flow channel 242 has a narrower channel, which increases the gas velocity. The high-speed airflow flows directly through the outer wall of the conductive nozzle 22, cools the conductive nozzle 22 through convection heat transfer, and is ejected from the larger opening at a gentle flow rate to cover the outlet area of ​​the welding wire 114.

[0075] The inner isolation tube 23 is fastened to the inner connecting groove 3 of the nozzle 21 through the elastic connecting gasket 31 on the outer wall of the mounting plate 25. Combined with the fit between the mounting plate 25 and the nozzle 21 and the upward lifting force generated by the gas flow, the stability during operation is ensured. The height difference between its bottom end and the bottom end of the nozzle 21 can enhance the spatter shielding effect and optimize the layering of gas protection. After welding is completed, the welding torch trigger 121 is released, the switch assembly is disconnected, and the current, wire feeding and gas delivery stop simultaneously, completing the welding process.

[0076] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A steel structure electric arc welding equipment for building construction, comprising a welding gun (1) consisting of a front tube (11) and a rear tube (12); The welding torch front tube (11) includes a wire feeding conduit (111) and a shielding gas passage (112). The wire feeding conduit (111) is used to continuously feed the welding wire (114). The welding head connecting pipe (113) is sealed to the wire feeding guide (111) and the protective gas channel (112), and a nozzle structure (2) is threaded at its bottom. Its characteristic is that: The nozzle structure (2) includes a hollow nozzle (21) and a conductive nozzle (22) extending from the inside of the welding head connecting pipe (113). The conductive nozzle (22) is centered inside the nozzle (21), and the welding wire (114) is located inside the conductive nozzle (22). The nozzle (21) is fitted with a ceramic material isolation inner tube (23), which separates the gas flow channel (24) formed between the nozzle (21) and the conductive nozzle (22); The lower end of the isolation inner tube (23) extends outward from the nozzle (21) and is flared outward, which reduces the entry of high-temperature spatter during welding into the outer gas flow channel (24) through physical shielding; The gas flow channel (24) on the inner side leads directly to the outer wall of the contact tip (22), which specifically guides the protective gas to the outlet area of ​​the welding wire (114), enhancing the protection effect of the molten pool. At the same time, the high-speed airflow flows through the surface of the contact tip (22), which can cool it at a specific point.

2. The arc welding equipment for steel structures in building construction according to claim 1, characterized in that: The welding torch rear tube (12) includes a welding torch trigger (121), a main pipeline (122), and an input interface structure (123); The main pipeline (122) integrates a channel for conveying welding wire (114) and a protective gas transmission channel. One end of the channel is adapted to the welding torch trigger (121), and the other end extends to the input interface structure (123). The input interface structure (123) is used to connect the protective gas source, welding wire (114) required for welding and to the power supply, so as to realize the docking of the external medium with the channel inside the main pipeline (122).

3. The arc welding equipment for steel structures in building construction according to claim 1, characterized in that: The top of the isolation inner tube (23) is connected to the mounting plate (25). The surface of the mounting plate (25) is provided with multiple annular channels. The outer annular channel is the outflow port (26), and the inner annular channel is the inflow port (27).

4. The arc welding equipment for steel structures in building construction according to claim 3, characterized in that: The isolation inner tube (23) divides the gas flow channel (24) into an outer branch channel (241) and an inner branch channel (242), and performs a diversion operation on the protective gas in the gas flow channel (24) by means of the outer outlet (26) and the inner outlet (27).

5. The arc welding equipment for steel structures in building construction according to claim 4, characterized in that: The lower opening of the outer branch channel (241) is smaller than the lower opening of the inner branch channel (242).

6. The arc welding equipment for steel structures in building construction according to claim 1, characterized in that: The lower end of the inner isolation tube (23) has an outward expansion structure that forms ∠a, and ∠a is 30°-45°.

7. The arc welding equipment for steel structures in building construction according to claim 1, characterized in that: The outer wall of the isolation inner tube (23) and the inner wall of the nozzle (21) are both provided with spiral grooves (4). The two spiral grooves (4) cooperate with each other to form a spiral channel (41) for the outer diversion channel (241).

8. The arc welding equipment for steel structures in building construction according to claim 3, characterized in that: A connecting gasket (31) is fixedly installed on the outer wall of the mounting plate (25). An inner connecting groove (3) is opened at the upper end of the inner cavity of the nozzle (21). The connecting gasket (31) is fastened to the inside of the inner connecting groove (3) to realize the installation and fixation of the isolation inner tube (23).

9. The arc welding equipment for steel structures in building construction according to claim 1, characterized in that: The bottom end of the isolation inner tube (23) and the bottom end of the nozzle (21) form a height difference L, the height difference L being 5-15 mm.

10. The arc welding equipment for steel structures in building construction according to claim 8, characterized in that: The nozzle (21) has an inclined angle (210) at its bottom, which is used to reduce the resistance of the protective gas in the outer diversion channel (241).

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