An ultra-long TIG arc narrow gap welding device

Abstract

The present invention provides an ultra-long TIG arc narrow gap welding device and method, and relates to the technical field of non-melting electrode gas shielded welding. Among them, the ultra-long TIG arc narrow gap welding device includes: an ultra-long TIG arc welding machine, the ultra-long TIG arc welding machine has a non-transferred arc power supply negative electrode interface, a TIG power supply negative electrode interface and a positive electrode interface; the positive electrode interface is used to connect with the workpiece to be welded; an ultra-long TIG arc welding gun, the nozzle aperture of the welding gun of the ultra-long TIG arc welding gun is 4-6mm, which is used to generate a laminar plasma arc; the tungsten electrode of the ultra-long TIG arc welding gun is connected to the non-transferred arc power supply negative electrode interface and the TIG power supply negative electrode interface of the ultra-long TIG arc welding machine through a connecting line. In this way, by directly introducing the arc into the bottom of the groove, the gap between thick plates is reduced, the amount of welding wire filling is reduced and the welding efficiency is improved; the long arc has good coverage of the bottom of the narrow gap groove, which can effectively improve the poor fusion of the side wall, which is conducive to improving the welding efficiency and welding quality, and is particularly suitable for thick plate narrow gap welding.

Description

Technical Field

[0001] The invention relates to the technical field of non-metallic electrode gas shielded welding, and in particular to an ultra-long TIG arc narrow gap welding device and method. Background Art

[0002] The existing TIG arc welding and plasma arc welding are two welding methods, which are generally used alone.

[0003] The arc length of the existing TIG arc is relatively short, about 4 mm. When welding thick plates, the welding gun needs to be extended as a whole into the groove gap, resulting in a wider groove gap to be processed, a large amount of welding wire filling, and low efficiency. At the same time, due to the short arc length and the limited range of movement of the welding gun in the narrow gap, it is unable to cover the bottom side wall of the narrow gap of the thick plate well, which can easily cause insufficient heat input to the bottom side wall and poor fusion.

[0004] The tungsten electrode nozzle aperture of the existing plasma welding gun that produces non-transferred arc is 2mm-3mm, and the arc produced is a turbulent plasma arc with a short arc length and a jet shape, which is not suitable for narrow gap thick plate welding.

[0005] Existing laminar plasma generators can generate laminar plasma arcs with very long arc lengths. However, due to the low arc heat and low energy density, it is difficult to melt through the workpiece in a short period of time. Currently, they are only used in metal cutting, material surface strengthening treatment and 3D printing, and are also not suitable for thick plate narrow gap welding.

[0006] Therefore, the present invention provides a new welding device and method, which can be used for welding thick plates with narrow gaps and where the welding gun is not directly introduced into the bottom of the gap by generating an ultra-long TIG arc. Summary of the invention

[0007] The purpose of the present invention is to provide an ultra-long TIG arc narrow gap welding device to solve the problems of short arc length, low welding efficiency and poor effect in narrow gap welding in the prior art, where the welding gun needs to be introduced into the bottom of the gap. The present invention further reduces the gap between thick plates, reduces the amount of welding wire filling and improves welding efficiency by directly introducing the arc into the bottom of the groove; at the same time, the long arc has good coverage of the bottom of the narrow gap groove, which can effectively improve the poor fusion of the side wall.

[0008] In order to achieve the above-mentioned purpose, according to a first aspect of the present invention, there is provided an ultra-long TIG arc narrow gap welding device, the ultra-long TIG arc narrow gap welding device comprising: an ultra-long TIG arc welding machine, the ultra-long TIG arc welding machine having a non-transferred arc power supply negative electrode interface, a TIG power supply negative electrode interface and a positive electrode interface; the positive electrode interface is used to connect with a workpiece to be welded; an ultra-long TIG arc welding gun, the nozzle aperture in the welding gun of the ultra-long TIG arc welding gun is 4-6mm, and is used to generate a laminar plasma arc; the tungsten electrode of the ultra-long TIG arc welding gun is respectively connected to the non-transferred arc power supply negative electrode interface and the TIG power supply negative electrode interface of the ultra-long TIG arc welding machine through connecting lines.

[0009] Furthermore, the output current of the negative electrode interface of the non-transferred arc power supply is 0.5-150 A; the output current of the negative electrode interface of the TIG power supply is 0.5-300 A.

[0010] Furthermore, the ultra-long TIG arc narrow gap welding device also includes: a wire feeder; a wire feeding tube, which is connected to the wire feeder; the wire feeding tube is obliquely arranged on one side of the ultra-long TIG arc welding gun; the wire feeding tube moves synchronously with the ultra-long TIG arc welding gun; a workbench, which is arranged below the ultra-long TIG arc welding gun and is used to place the workpiece to be welded; the ultra-long TIG arc welding gun is located above the workpiece to be welded and can move in the horizontal direction of the narrow gap of the workpiece to be welded.

[0011] Furthermore, the ultra-long TIG arc narrow gap welding device also includes a clamping mechanism, which is arranged on one side of the ultra-long TIG arc welding gun and is used to clamp the wire feeding tube; the angle between the wire feeding tube and the tungsten electrode is 45°.

[0012] Furthermore, the extra-long TIG arc welding machine and the extra-long TIG arc welding gun both have a cooling water channel, and the water inlet and the water outlet of the cooling water channel are used to be connected to the water cooling system.

[0013] Furthermore, the ultra-long TIG arc narrow gap welding device includes: a camera, which is arranged on one side of the ultra-long TIG arc welding gun, and the lens of the camera is arranged relative to the groove gap of the workpiece to be welded; the lens of the camera is horizontal to the workpiece to be welded, and the distance between the lens of the camera and the ultra-long TIG arc welding gun is greater than or equal to 20 cm; the camera is connected to the ultra-long TIG arc welding gun through a clamp so as to move synchronously with the ultra-long TIG arc welding gun; the camera is used to connect to a computer.

[0014] According to another aspect of the present invention, an ultra-long TIG arc narrow gap welding method is also provided. The ultra-long TIG arc narrow gap welding method is implemented by using the ultra-long TIG arc narrow gap welding device mentioned above. The method comprises the following steps: controlling the ultra-long TIG arc welding gun to move to the starting position of the workpiece to be welded; turning on the non-transferred arc power switch of the ultra-long TIG arc welding machine, so that the ultra-long TIG arc welding gun generates a non-transferred arc, and the laminar plasma generated under the high temperature of the non-transferred arc is ejected from the nozzle inside the welding gun of the ultra-long TIG arc welding gun; adjusting the non-transferred arc current of the ultra-long TIG arc welding machine so that the laminar plasma The length of the ejected particle reaches the bottom of the narrow gap groove of the workpiece to be welded; turn on the TIG power switch of the ultra-long TIG arc welding machine, so that the TIG long arc can reach the bottom of the narrow gap groove of the workpiece to be welded with the help of laminar plasma to start the arc; use the robot arm to clamp and drive the ultra-long TIG arc welding gun to move along the center line of the groove from the starting position of the workpiece to be welded to the end position of the workpiece to be welded; during the mobile welding process, the non-transferred arc power switch and the TIG power switch are always in the on state; according to the thickness of the workpiece to be welded, repeat the above steps to perform narrow gap single-pass multi-layer welding until the narrow gap groove is filled.

[0015] Furthermore, when the ultra-long TIG arc narrow gap welding device includes a camera and a computer, the method also includes the following steps: collecting the arc shape through the camera; adjusting the clarity of the camera; and observing the state of the arc, molten droplet and molten pool through the computer.

[0016] Furthermore, before turning on the non-transferred arc power switch of the ultra-long TIG arc welding machine, the method also includes the following steps: selecting a welding wire of a certain size, selecting a plate with a certain plate thickness and groove gap as the workpiece to be welded, and selecting certain welding process parameters; the welding process parameters include non-transferred arc current, TIG current, wire feeding speed, welding speed, ion gas flow rate, shielding gas flow rate, tungsten electrode retraction amount, and the height of the ultra-long TIG arc welding gun from the upper surface of the workpiece to be welded.

[0017] Furthermore, the welding wire diameter is 1.2 mm, the plate thickness is 20-60 mm, the arc length is 20-60 mm; the groove gap is 6mm-20 mm; the non-transferred arc current is 26-150 A, the TIG current is 50-300 A, the wire feeding speed is 10-40 mm / s, the welding speed is 0.5-4mm / s, the ion gas flow rate is 0.5-5 L / min, the shielding gas flow rate is 5-25 L / min, the tungsten electrode retraction amount is 0.5-3 mm, and the height of the super-long TIG arc welding gun from the upper surface of the workpiece to be welded is 1-3 mm.

[0018] By applying the technical solution of the present invention, the existing welding gun structure is improved, and the nozzle aperture of the welding gun of the super-long TIG arc welding gun is adjusted to 4-6mm, so that a laminar plasma arc can be generated. By adjusting the current of the non-transferred arc, the ejection length of the laminar plasma arc can be adjusted. The length of the laminar plasma arc can reach 60mm. Under the constraint of the laminar plasma arc, the TIG arc does not directly start with the groove side wall or the workpiece surface close to the tungsten electrode, but extends to the bottom of the groove to start the arc, so that an ultra-long TIG arc that reaches the bottom of the groove can be generated. In this way, the super-long TIG arc welding gun provided by the present invention does not need to extend into the narrow gap groove of the workpiece to be welded, so that a narrow groove gap can be set, and the amount of welding wire filling is reduced, which is conducive to improving welding efficiency. At the same time, the super-long TIG arc can reach the bottom of the groove directly, the heat input of the bottom side wall is sufficient, and the fusion effect is good, which solves the defect of poor side wall fusion during traditional narrow gap TIG welding. In addition, the present invention utilizes the combination of non-transferred arc and TIG arc, the arc energy density is relatively high, and the workpiece can be melted through in a short time, and is suitable for narrow gap welding of thick plates.

[0019] The present invention generates an ultra-long TIG arc, and the welding gun does not need to extend into the groove gap, so as to reduce the groove gap and the amount of welding wire filling, thereby improving welding efficiency and reducing welding deformation; at the same time, the ultra-long TIG arc is injected into the narrow gap groove, so that the groove bottom and the side wall of the groove bottom are covered by the arc, thereby improving the poor fusion of the side wall.

[0020] Based on the implementations provided in the above aspects, this application can also be further combined to provide more implementations. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 A schematic structural diagram of an ultra-long TIG arc narrow gap welding device provided in an optional embodiment of the present invention;

[0023] Figure 2 Shows Figure 1 Left view of

[0024] Figure 3 Shows Figure 2 A top view of a part of the structure;

[0025] Figure 4The figure shows an image observed by a camera of an ultra-long TIG arc narrow gap welding device provided by an optional embodiment of the present invention.

[0026] Description of Figure Numbers:

[0027] 1. Computer; 2. Workbench; 3. Workpiece to be welded; 4. Camera; 5. Wire feed tube; 6. Water cooling system; 7. Wire feeder; 8. Extra-long TIG arc welding machine; 9. Extra-long TIG arc welding gun; 10. TIG long arc; 11. Tungsten electrode; 12. Inner nozzle of welding gun; 13. Outer nozzle of welding gun. DETAILED DESCRIPTION

[0028] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the structure and method of the welding device are improved, and the structure and method of the welding device in the prior art can be adopted.

[0029] like Figures 1 to 3 As shown, an optional embodiment of the present invention provides an ultra-long TIG arc narrow gap welding device, which includes an ultra-long TIG arc welder 8 and an ultra-long TIG arc welding gun 9. The ultra-long TIG arc welder 8 has a non-transferred arc power supply negative electrode interface, a TIG power supply negative electrode interface and a positive electrode interface; the positive electrode interface is used to connect to the workpiece to be welded, and the aperture of the nozzle 12 in the welding gun of the ultra-long TIG arc welding gun 9 is 4-6mm, which is used to generate a laminar plasma arc; the tungsten electrode 11 of the ultra-long TIG arc welding gun 9 is connected to the non-transferred arc power supply negative electrode interface and the TIG power supply negative electrode interface of the ultra-long TIG arc welding machine through connecting lines.

[0030] The present invention adjusts the aperture of the nozzle 12 in the welding gun. Experimental verification shows that adjusting the aperture of the nozzle 12 in the welding gun to 4-6 mm can generate a laminar plasma arc with a longer length, thereby reaching the bottom of the groove directly.

[0031] Too small or too large an aperture will easily cause the plasma to be ejected in a short length and fail to reach the bottom of the narrow gap, thus failing to generate an ultra-long TIG arc. The nozzle aperture in the welding gun within the above numerical range can generate a long laminar plasma arc that reaches the bottom of the groove.

[0032] Furthermore, the present invention combines the non-transferred arc and the TIG arc for use, and utilizes the non-transferred arc to constrain the arc starting position of the TIG arc, so that the length of the TIG arc can be up to 60 mm, and can directly reach the bottom of the groove of a 60 mm thick plate, so that the heat input to the bottom side wall is sufficient and the fusion effect is better, thereby solving the defect of poor side wall fusion in traditional narrow gap TIG welding, thereby improving the welding effect and improving the welding quality.

[0033] In addition, the present invention utilizes the combination of non-transferred arc and TIG arc, the arc energy density is relatively high, and the workpiece can be melted through in a short time, and is suitable for narrow gap welding of thick plates of 20-60 mm.

[0034] Since the arc length of the non-transferred arc and the TIG arc is longer, the welding gun does not need to be inserted into the groove gap, so that the groove gap can be set narrower, thereby reducing the amount of welding wire filling and improving welding efficiency. Experimental verification shows that the application of the technical solution of the present invention can improve the welding efficiency by about 30% compared with the existing technical solution, which has a significant effect.

[0035] The present invention innovatively improves the structure of the welding gun, thereby being able to generate a laminar plasma arc with a longer length, broadening the technical scope of the prior art that can only apply the laminar plasma arc to fields such as surface treatment, and using it in conjunction with the TIG arc to achieve narrow gap welding of thick plates, with better welding efficiency and welding effect.

[0036] It should be noted that the non-transferred arc is a form of plasma arc established between the tungsten electrode 11 and the nozzle 12 in the welding gun during plasma arc welding; the TIG arc is an arc started between the tungsten electrode 11 and the workpiece 3 to be welded.

[0037] When the welding device provided by the present invention is in use, the non-transferred arc and the TIG arc are combined. The non-transferred arc power supply is turned on first, and then the TIG arc power supply is turned on. By optimizing the process sequence, the TIG arc is constrained by the non-transferred arc, so that the TIG arc does not directly start with the side wall of the groove close to the tungsten electrode 11 or the surface of the workpiece 3 to be welded, but extends to the bottom of the groove to start the arc, forming an ultra-long TIG arc. During the welding process, the non-transferred arc power supply and the TIG arc power supply are both in the on state, and the TIG arc shape remains stable during the entire welding process.

[0038] Optionally, the output current of the negative electrode interface of the non-transferred arc power supply is 0.5-150 A; the output current of the negative electrode interface of the TIG power supply is 0.5-300 A. Experimental verification shows that the effect is better when the output current of the non-transferred arc and the TIG arc is adjusted within the above value range.

[0039] By adjusting the output current of the non-transferred arc, the length of the non-transferred arc can be adjusted so that it can reach the bottom of the groove; by adjusting the output current of the TIG arc, the shape of the TIG arc can be adjusted, and the width of the arc can be adjusted so that it can reach the bottom of the groove and completely cover the side wall, achieving a better side wall fusion effect.

[0040] When the workpiece to be welded is a 20-60 mm thick plate, preferably, the output current of the negative electrode interface of the non-transferred arc power supply is 26-150 A; the output current of the negative electrode interface of the TIG power supply is 50-300 A. Experimental verification shows that when the output current of the non-transferred arc and the output current of the TIG arc are within the above numerical range, it is more suitable for thick plate narrow gap welding.

[0041] Alternatively, if Figure 1 As shown, the ultra-long TIG arc narrow gap welding device also includes: a wire feeder 7; a wire feeding tube 5, which is connected to the wire feeder 7; the wire feeding tube 5 is tilted and arranged on one side of the ultra-long TIG arc welding gun 9; the wire feeding tube 5 moves synchronously with the ultra-long TIG arc welding gun 9; a workbench 2, which is arranged below the ultra-long TIG arc welding gun 9 and is used to place the workpiece 3 to be welded; the ultra-long TIG arc welding gun 9 is located above the workpiece 3 to be welded, and can move in the horizontal direction of the narrow gap of the workpiece 3 to be welded. In this way, welding is achieved by using the wire feeding tube 5 in conjunction with the ultra-long TIG arc welding gun 9. The tilted setting absorbs the advantages of TOPTIG, which is conducive to feeding the welding wire to the area with the highest arc temperature directly below the welding gun, and can improve the melting efficiency of the welding wire.

[0042] The smaller the angle between the wire feeding tube 5 and the tungsten electrode 11 is, the better, which can improve the melting efficiency of the welding wire.

[0043] Optionally, the ultra-long TIG arc narrow gap welding device further includes a clamping mechanism, which is disposed on one side of the ultra-long TIG arc welding gun and is used to clamp the wire feeding tube 5 .

[0044] Optionally, the clamping mechanism is connected to the extra-long TIG arc welding gun 9 so that the wire feeding tube 5 is connected to the extra-long TIG arc welding gun 9 through the clamping mechanism. When the robot arm drives the extra-long TIG arc welding gun 9 to move, the wire feeding tube 5 can move synchronously with the extra-long TIG arc welding gun 9.

[0045] Optionally, the angle between the wire feeding tube 5 and the tungsten electrode 11 is 45°. Considering the influence of the size and angle of the nozzle outside the welding gun, the minimum angle is 45°. Therefore, it is preferred to ensure that the angle between the wire feeding tube 5 and the tungsten electrode 11 is 45° through a clamping mechanism. And this angle is always maintained during the welding process.

[0046] Optionally, a fixing mechanism is provided on the workbench 2 for fixing the workpiece 3 to be welded to prevent the workpiece 3 to be welded from being greatly deformed during welding.

[0047] Optionally, the super-long TIG arc welder and the super-long TIG arc welding gun both have a cooling water channel, and the water inlet and the water outlet of the cooling water channel are used to be connected to the water cooling system 6. In this way, the water cooling system 6 can be used to cool the super-long TIG arc welder 8 and the super-long TIG arc welding gun 9, thereby protecting the electrodes, avoiding high temperature damage, and extending the service life of the super-long TIG arc welder 8 and the super-long TIG arc welding gun 9.

[0048] Optionally, the nozzle 12 in the welding gun is a hollow structure, and a cooling water channel is formed inside the nozzle.

[0049] Optionally, the ultra-long TIG arc welding gun 9 further comprises an outer welding gun nozzle 13, which is sleeved on the outer side of the inner welding gun nozzle 12. A shielding gas channel is formed between the outer welding gun nozzle 13 and the inner welding gun nozzle 12. An ion gas channel is formed between the inner welding gun nozzle 12 and the tungsten electrode 11.

[0050] Optionally, the ultra-long TIG arc narrow gap welding device includes: a camera 4, the camera 4 is arranged on one side of the ultra-long TIG arc welding gun 9, and the lens of the camera 4 is arranged relative to the groove gap of the workpiece 3 to be welded. In this way, adding the camera 4 can more intuitively observe the shape of the long arc in the welding process in real time, obtain observation data, adjust the data according to the observation results, obtain the preferred parameter range, and then ensure the welding quality.

[0051] Optionally, the lens of the camera 4 is level with the workpiece to be welded. The camera 4 is level with the workpiece so that the arc shape can be observed, which is conducive to obtaining better observation data.

[0052] Optionally, the distance between the lens of the camera 4 and the super-long TIG arc welding gun 9 is greater than or equal to 20 cm. Since the radiation temperature of the welding arc is too high, the camera 4 cannot withstand high temperatures and should be set 20 cm away to ensure the observation quality while avoiding damage to the camera 4.

[0053] Optionally, the camera 4 is connected to the super-long TIG arc welding gun 9 through a fixture to move synchronously with the super-long TIG arc welding gun. In this way, the camera 4 can capture the shape of the arc generated by the super-long TIG arc welding gun 9 during the welding process in real time.

[0054] Optionally, the camera 4 is used to connect to the computer 1. In this way, the arc morphology can be observed and analyzed in real time and intuitively using the computer 1.

[0055] The present invention also provides an ultra-long TIG arc narrow gap welding method, which is realized by using the ultra-long TIG arc narrow gap welding device. The method comprises the following steps: controlling the ultra-long TIG arc welding gun 9 to move to the starting position of the workpiece 3 to be welded; turning on the non-transferred arc power switch of the ultra-long TIG arc welding machine 8, so that the ultra-long TIG arc welding gun 9 generates a non-transferred arc, and the laminar plasma generated under the high temperature of the non-transferred arc is ejected from the nozzle 12 inside the welding gun of the ultra-long TIG arc welding gun 9; adjusting the non-transferred arc current of the ultra-long TIG arc welding machine 8 so that the laminar plasma ejected from the workpiece 3 is ejected; and adjusting the non-transferred arc current of the ultra-long TIG arc welding machine 8 so that the laminar plasma ejected from the workpiece 3 is ejected. The degree reaches the bottom of the narrow gap groove of the workpiece 3 to be welded; turn on the TIG power switch of the ultra-long TIG arc welding machine, so that the TIG long arc reaches the bottom of the narrow gap groove of the workpiece 3 to be welded with the help of laminar plasma to start the arc; use a robot arm (not shown in the figure) to clamp and drive the ultra-long TIG arc welding gun 9 to move along the center line of the groove from the starting position of the workpiece 3 to be welded to the end position of the workpiece 3 to be welded; during the mobile welding process, the non-transferred arc power switch and the TIG power switch are always in the on state; according to the thickness of the workpiece 3 to be welded, repeat the above steps to perform narrow gap single-pass multi-layer welding until the narrow gap groove is filled. The welding method provided by the present invention combines the non-transferred arc and the TIG arc, and optimizes the process sequence, and uses the ultra-long TIG arc provided by the present invention to generate the laminar plasma that can reach the bottom of the slope directly and the ultra-long TIG arc to improve the welding efficiency and achieve a better welding effect. The present invention further reduces the gap between thick plates, reduces the amount of welding wire filling and improves welding efficiency by directly introducing the arc into the bottom of the groove; at the same time, the long arc has good coverage of the bottom of the narrow gap groove, which can effectively improve the poor fusion of the side wall.

[0056] Optionally, when the ultra-long TIG arc narrow gap welding device includes a camera 4 and a computer 1, the method further includes the following steps: collecting arc morphology through the camera 4; adjusting the clarity of the camera 4; and observing the states of the arc, molten droplet, and molten pool through the computer 1. In this way, the camera 4 is used to obtain real-time arc morphology images, the arc morphology is adjusted in time, and the numerical range of each parameter is obtained, which is conducive to further improving welding efficiency and ensuring welding effect. The camera 4 can also be used to obtain real-time molten droplet state and molten pool state, and adjustments are made as needed to ensure welding effect.

[0057] Optionally, the clarity of the camera can be adjusted by a focus knob on the camera 4, so that the states of the arc, molten droplet and molten pool can be better observed.

[0058] Since the wire feeding speed is fixed, if the current is too low, the wire will drip into the molten pool before it is completely melted, affecting the welding effect; when the current is reduced, the molten pool area will decrease. If the current is too low, the bottom metal will not melt and a molten pool cannot be formed. Among them, the size of the non-transferred arc current is compared with the size of the TIG current, and the size of the TIG current has a greater impact on the molten droplet and the molten pool.

[0059] like Figure 4 As shown, taking the "U"-shaped groove as an example, when the non-transferred arc power supply and the TIG arc power supply are turned on at the same time, the image obtained by the camera 4 shows that the super-long arc composed of the non-transferred arc and the TIG arc forms a light column. By adjusting the magnitude of the non-transferred arc current and the magnitude of the TIG current, the super-long arc can be Figure 4 As shown in the figure, it reaches the bottom of the groove; the high temperature of the ultra-long arc can melt the welding wire to form molten droplets, and the molten pool is the metal liquid formed by the ultra-long arc melting the metal below and the side wall near the bottom. Figure 4 As shown, the image obtained by the camera 4 can also observe the state of the molten droplet and the molten pool. When the state of the molten droplet and the molten pool in the observed image does not meet the welding requirements, the size of the non-transferred arc current and the size of the TIG current can be adjusted immediately to ensure the welding effect.

[0060] Preferably, the present application is more suitable for "I" type straight grooves, and the welding efficiency is higher than that of "U" type grooves. This is because the processing difficulty of "U" type grooves is greater than that of "I" type grooves, so the gap of "I" type grooves can be smaller, less welding wire is needed to fill, and the working efficiency is higher.

[0061] Optionally, before turning on the non-transferred arc power switch of the super-long TIG arc welding machine, the method further includes the following steps: selecting a welding wire of a certain size, selecting a plate with a certain plate thickness and groove gap as the workpiece to be welded, and selecting certain welding process parameters; the welding process parameters include non-transferred arc current, TIG current, wire feeding speed, welding speed, ion gas flow rate, shielding gas flow rate, tungsten electrode retraction, and the height of the super-long TIG arc welding gun from the upper surface of the workpiece to be welded. The values ​​of the above parameters are selected according to actual needs to achieve welding.

[0062] Optionally, the diameter of the welding wire is 1.2 mm, the plate thickness is 20-60 mm, the arc length is 20-60 mm; the groove gap is 6mm-20 mm; the non-transferred arc current is 26-150 A, the TIG current is 50-300 A, the wire feeding speed is 10-40 mm / s, the welding speed is 0.5-4mm / s, the ion gas flow rate is 0.5-5 L / min, the shielding gas flow rate is 5-25 L / min, the tungsten electrode retraction is 0.5-3 mm, and the height of the super-long TIG arc welding gun from the upper surface of the workpiece to be welded is 1-3 mm. When the parameters are within the above numerical range, the defect of poor side wall fusion in traditional narrow gap TIG welding is solved, and the welding efficiency is improved by more than 30%; the super-long TIG arc is used to inject into the groove without the need for the welding gun to be inserted, and 20-60 mm thick plate welding can be achieved.

[0063] Among them, the non-transferred arc current can adjust the arc length, and the TIG current can adjust the arc width; when the groove gap is large, the wire feeding speed should be increased accordingly and the welding speed should be reduced; appropriate ion gas flow rate and shielding gas flow rate can obtain a stable arc.

[0064] When welding in a narrow gap, different welding process parameters should be matched according to different plate thicknesses and groove gaps, so as to obtain a good arc shape and a good welding effect. When welding, appropriate values ​​can be selected within the above value range according to actual needs.

[0065] Of course, welding parameters outside the above numerical range may also be selected according to actual needs.

[0066] The invention is suitable for high-efficiency and high-quality welding of thick plate metal materials.

[0067] An optional embodiment of the present invention provides a device for ultra-long TIG arc narrow gap welding, including a welding gun, which is an ultra-long TIG arc welding gun capable of generating a laminar plasma arc, the welding gun is connected to a welding machine, a wire feeding tube is obliquely arranged on one side of the welding gun, and the wire feeding tube is connected to a wire feeding machine; the welding machine is an ultra-long TIG arc welding machine, including a non-transferred arc power interface and a TIG power interface; a workbench is arranged below the welding gun, and the workbench is used to place workpieces; the tungsten electrode nozzle aperture of the welding gun is 4-6 mm, the output current of the non-transferred arc power interface of the welding machine is 0.5-150 A, and the output current of the TIG power interface is 0.5-300 A. The welding gun and the welding machine are connected with cooling water, and the cooling water pipe is connected to the water cooling system through the water inlet and the water outlet respectively. A camera is fixedly arranged on one side of the welding gun by a clamp, the lens of the camera is horizontal to the ultra-long TIG arc welding gun and the distance is not less than 20 cm, and the camera is connected to a computer.

[0068] The optional embodiment of the present invention also provides a method for ultra-long TIG arc narrow gap welding, which adjusts the length and width of the arc by adjusting the size of the non-transferred arc current and the TIG current, so that the arc shape matches the narrow gap groove gap and the plate thickness, and performs narrow gap welding, including the following steps: Step 1: Select a welding wire of a certain size, select a plate with a certain plate thickness and groove gap, and select certain welding process parameters, the welding process parameters include non-transferred arc current, TIG current, wire feeding speed, welding speed, ion gas flow rate, shielding gas flow rate, tungsten electrode retraction, and the height of the welding gun from the upper surface of the workpiece; Step 2: Connect the positive electrode of the welding machine to the Connect the workpiece, connect the non-transferred arc power interface of the welding machine and the TIG power interface to the welding gun; Step three: arc starting, the welding gun is in the starting position, turn on the non-transferred arc power switch of the welding machine, the welding gun will generate a non-transferred arc, and the plasma generated under the high temperature of the non-transferred arc will be ejected from the nozzle of the welding gun for a distance. By adjusting the non-transferred arc current of the welding machine, the plasma ejection length can reach the bottom of the narrow gap groove of the workpiece; then turn on the TIG power switch of the welding machine, and the TIG long arc will reach the bottom of the groove of the workpiece with the help of the above plasma to start the arc; Step four: welding, use a robot arm to drive the welding gun along the center line of the groove from the starting position to the end position. During welding, the non-transferred arc is not extinguished, which is used to constrain the long TIG arc and prevent the arc from directly starting with the groove side wall or workpiece surface close to the tungsten electrode; Step 5: Repeat steps 3 and 4 according to the thickness of the plate to perform narrow gap single-pass multi-layer welding until the narrow gap groove is filled; Step 6: Collect the arc shape. After adjusting the clarity, the camera moves synchronously with the welding gun during the welding process, and the status of the arc, molten droplet and molten pool can be clearly observed through the computer.

[0069] Among them, the wire diameter is 1.2 mm, the non-transferred arc current is 26-150 A, the TIG current is 50-300 A, the wire feeding speed is 10-40 mm / s, the welding speed is 0.5-4 mm / s, the ion gas flow rate is 0.5-5 L / min, the shielding gas flow rate is 5-25 L / min, the tungsten electrode retraction is 0.5-3 mm, the height of the welding gun from the upper surface of the workpiece is 1-3 mm, and the groove gap is 6-20 mm. Experimental verification shows that when the parameters are within the above numerical range, the welding effect is better and the welding efficiency is higher.

[0070] Narrow gap TIG welding is developed from TIG welding with large grooves. Due to the short arc length of about 4 mm, when welding thick plates, the welding gun needs to be inserted into the groove gap as a whole. The disadvantage is that the processed groove gap is wide, the amount of welding wire filling is large, and the efficiency is low. At the same time, the arc cannot cover the bottom side wall of the narrow gap of the thick plate, which can easily cause insufficient heat input to the side wall and poor fusion. The welding devices and methods in the related art are not suitable for narrow gap welding of thick plates.

[0071] The invention discloses an apparatus and method for ultra-long TIG arc narrow gap welding, which belong to the technical field of non-melting electrode gas shielded welding. The apparatus comprises a welding gun, which is an ultra-long TIG arc welding gun capable of generating a laminar plasma arc, the welding gun being connected to a welding machine, a wire feeding tube being obliquely arranged on one side of the welding gun, and the wire feeding tube being connected to the wire feeding machine. The welding machine is an ultra-long TIG arc welding machine, comprising a non-transferred arc power supply interface and a TIG power supply interface. A workbench is arranged below the welding gun, and the workbench is used for placing workpieces. Based on the method of the apparatus, in the narrow gap welding process, an ultra-long TIG arc is injected into the narrow gap groove, so that the groove bottom and the groove bottom side wall are covered by the arc, thereby improving the poor fusion of the side wall. Through the ultra-long TIG arc, the welding gun does not need to extend into the groove gap, thereby reducing the groove gap and improving the welding efficiency, and is suitable for high-efficiency and high-quality welding of thick plate metal materials.

[0072] It should be noted that the arc length of a conventional TIG arc is about 4 mm. In comparison, the TIG arc of the present invention is elongated to 20-60 mm, which can be called super long.

[0073] Compared with the prior art, the present invention has achieved the following technical effects:

[0074] The present invention injects an ultra-long TIG arc into the narrow gap groove, so that the groove bottom and the side wall of the groove bottom are covered by the arc, thereby improving the poor fusion of the side wall; through the ultra-long TIG arc, the welding gun does not need to extend into the groove gap, so the groove gap can be reduced and the welding efficiency is improved.

[0075] By applying the method provided by the present invention, it is possible to achieve narrow gap welding of thick plates, and has better welding effect and higher welding efficiency.

[0076] An optional embodiment of the present invention provides an apparatus and method for ultra-long TIG arc narrow gap welding, such as Figure 1As shown, it includes a welding gun, which is an extra-long TIG arc welding gun 9, which can generate a laminar plasma arc. The extra-long TIG arc welding gun 9 is connected to an extra-long TIG arc welding machine 8. A wire feeding tube 5 is obliquely arranged on one side of the extra-long TIG arc welding gun 9, and the wire feeding tube 5 is connected to a wire feeding machine 7; the extra-long TIG arc welding machine 8 includes a non-transferred arc power supply interface and a TIG power supply interface; a workbench 2 is arranged below the extra-long TIG arc welding gun 9, and the workbench 2 is used to place a workpiece 3 to be welded; the nozzle 12 in the welding gun of the extra-long TIG arc welding gun 9 has an aperture of 4-6mm, and the output current of the non-transferred arc power supply interface of the extra-long TIG arc welding machine 8 is 0.5-150 A, and the output current of the TIG power supply interface is 0.5-300 A. The extra-long TIG arc welding gun 9 and the extra-long TIG arc welding machine 8 are connected with cooling water, and the cooling water pipe is connected to the water cooling system 6 through the water inlet and the water outlet respectively. A camera 4 is fixedly arranged on one side of the super-long TIG arc welding gun 9 by a clamp, the lens of the camera 4 is horizontal to the super-long TIG arc welding gun 9 and the distance is not less than 20 cm, and the camera 4 is connected to the computer 1. The super-long TIG arc welding gun 9 and the super-long TIG arc welding machine 8 are respectively passed through cooling water.

[0077] The invention mainly adjusts the nozzle 12 to 4-6 mm in the welding gun so that it can generate a laminar plasma arc, and at the same time increases the 45° wire feeding tube clamping.

[0078] The specific implementation steps of the method of the present invention are as follows:

[0079] Step 1: Select 308 stainless steel welding wire with a diameter of 1.2 mm, select 304 stainless steel plate with a thickness of 20 mm and a groove gap of 10 mm, and select certain welding process parameters, including non-transferred arc current, TIG current, wire feeding speed, welding speed, ion gas flow rate, shielding gas flow rate, tungsten electrode retraction, and the height of the welding gun from the upper surface of the workpiece; among them, the groove is a straight "I"-shaped groove with a gap of 10 mm.

[0080] Step 2: Wiring, as shown in the attached Figure 1 As shown, the positive electrode of the super-long TIG arc welder 8 is connected to the workpiece 3 to be welded, and the non-transferred arc power interface and the TIG power interface of the super-long TIG arc welder 8 are connected to the super-long TIG arc welding gun 9;

[0081] Step 3: Arc starting. The ultra-long TIG arc welding gun 9 is in the starting position. The non-transferred arc power switch of the ultra-long TIG arc welding machine 8 is turned on. The ultra-long TIG arc welding gun 9 will generate a non-transferred arc. The plasma generated under the high temperature of the non-transferred arc will be ejected from the nozzle 12 in the welding gun for a distance. By adjusting the non-transferred arc current of the ultra-long TIG arc welding machine 8, the plasma ejection length can reach the bottom of the narrow gap groove of the workpiece 3 to be welded; then turn on the TIG power switch of the ultra-long TIG arc welding machine 8, and the TIG long arc 10 will use the above-mentioned plasma to reach the bottom of the groove of the workpiece 3 to be welded to start the arc.

[0082] Step 4: Welding, using a robot arm to drive the super-long TIG arc welding gun 9 from the starting position to the end position along the center line of the groove. The non-transferred arc does not extinguish during welding, which is used to constrain the TIG long arc 10 and prevent the arc from directly striking the groove side wall close to the tungsten electrode 11 or the surface of the workpiece 3 to be welded. Figure 2 and Figure 3 As shown, the arrow direction in the figure is the welding direction: Figure 2 In the figure, the wire feeding method adopts front wire feeding, that is, the wire feeding tube 5 is always kept in front and the tungsten electrode 11 is kept in the back during welding. The welding will be disturbed by environmental factors, so that the welding wire is not completely melted in the arc and drips into the molten pool. If the arc is in front and the welding wire is in the back, inclusions will be formed in the molten pool. The welding wire in front and the arc in the back can ensure that the subsequent arc will melt it when it passes, thereby ensuring the welding effect. The angle between the tungsten electrode 11 and the wire feeding tube 5 is 45°. Figure 3 In the top view, the tungsten electrode 11 and the wire feeding tube 5 always maintain the position shown in the figure with the weld bead during the process of moving from the starting position to the ending position.

[0083] Optionally, the starting position is an arc starting point position, and the ending position is an arc extinction point position.

[0084] Step 5: Repeat steps 3 and 4 5 times to perform narrow gap single-pass 5-layer welding to fill the narrow gap groove.

[0085] Step 6: Collecting the arc shape, after adjusting the clarity, the camera 4 moves synchronously with the super-long TIG arc welding gun 9 during the welding process, and the states of the arc, molten droplet and molten pool are clearly observed through the computer 1.

[0086] In step one, the non-transferred arc current is 26-150 A, the TIG current is 50-300 A, the wire feeding speed is 10-40 mm / s, the welding speed is 0.5-4 mm / s, the ion gas flow rate is 0.5-5 L / min, the shielding gas flow rate is 5-25 L / min, the tungsten electrode retraction amount is 0.5-3 mm, and the height of the welding gun from the upper surface of the workpiece is 1-3 mm.

[0087] The device and method for ultra-long TIG arc narrow gap welding provided by the present invention generate an ultra-long TIG arc, and the ultra-long TIG arc welding gun 9 does not need to extend into the groove gap, so as to reduce the groove gap and the amount of welding wire filling, thereby improving the welding efficiency and reducing the welding deformation; at the same time, the ultra-long TIG arc is injected into the narrow gap groove, so that the groove bottom and the side wall of the groove bottom are covered by the arc, thereby improving the poor fusion of the side wall.

[0088] The present invention can solve the defect of poor side wall fusion during traditional narrow gap TIG welding of 304 stainless steel under the following process parameters: a wire diameter of 1.2 mm, a non-transferred arc current of 26A, a TIG current of 250 A, a wire feeding speed of 25 mm / s, a welding speed of 1 mm / s, an ion gas flow rate of 3.5 L / min, a shielding gas flow rate of 18 L / min, a tungsten electrode retraction of 1 mm, and a height of 1 mm from the upper surface of the workpiece. The welding efficiency is increased by more than 30%. The ultra-long TIG arc is used to inject into the groove without the need for the welding gun to extend into the groove, and the welding of 20-60 mm thick plates can be achieved. The present invention is suitable for high-efficiency and high-quality welding of thick plate metal materials. Example

[0089] An experimental example is used below to illustrate that a 308 stainless steel welding wire with a diameter of 1.2 mm is used to perform narrow gap single-pass multi-layer welding on a 304 stainless steel plate with a thickness of 20 mm, the groove gap is 10 mm, the non-transferred arc current is 26 A, the wire feeding speed is 25 mm / s, the welding speed is 1 mm / s, the ion gas flow rate is 3.5 L / min, the shielding gas flow rate is 18 L / min, the tungsten electrode retraction amount is 1 mm, and the height of the welding gun from the upper surface of the workpiece is 1 mm. The present invention uses a high-speed camera to shoot the arc, molten droplet and molten pool for observation and analysis.

[0090] In this embodiment, the TIG current is adjusted, the arc shape and the corresponding welding effect are observed, and the comparison results in Table 1 are obtained.

[0091] Table 1 Changes in arc morphology and welding effect under different test parameters

[0092]

[0093] During welding, under the constraint of the non-transferred arc, the TIG arc did not start directly with the groove side wall or workpiece surface close to the tungsten electrode, but extended to the bottom of the groove to start the arc, forming an ultra-long TIG arc, and the arc shape remained stable throughout the welding process. As shown in Table 1, with the increase of TIG current, the bottom diameter of the ultra-long TIG arc gradually increased until it completely covered the side wall, and a good welding effect was obtained.

[0094] The parameters in Table 1 only represent the situation in Example 1, and other parameters within the range can be selected under other working conditions.

[0095] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by terms such as "center", "upper", "lower", "bottom", "inside", "outside", and "side" are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0096] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. An ultra-long TIG arc narrow gap welding device, characterized in that: The ultra-long TIG arc narrow gap welding device comprises: An extra-long TIG arc welder, wherein the extra-long TIG arc welder has a non-transferred arc power supply negative electrode interface, a TIG power supply negative electrode interface and a positive electrode interface; the positive electrode interface is used to connect to a workpiece to be welded; An extra-long TIG arc welding gun, wherein the nozzle aperture of the extra-long TIG arc welding gun is 4-6 mm, and is used to generate a laminar plasma arc; The tungsten electrode (11) of the super-long TIG arc welding gun (9) is connected to the non-transferred arc power supply negative electrode interface and the TIG power supply negative electrode interface of the super-long TIG arc welding machine through connecting wires; The non-transferred arc current is 26-150 A, the TIG current is 50-300 A, and the tungsten electrode retraction is 0.5-3 mm; The processing method adopted by the device includes the following steps: Control the extra-long TIG arc welding gun to move to the starting position of the workpiece to be welded; Turning on the non-transferred arc power switch of the ultra-long TIG arc welding machine, the ultra-long TIG arc welding gun generates a non-transferred arc, and laminar plasma generated at the high temperature of the non-transferred arc is ejected from the nozzle inside the welding gun of the ultra-long TIG arc welding gun; The non-transferred arc current of the ultra-long TIG arc welder is adjusted so that the length of the laminar plasma ejection reaches the bottom of the narrow gap groove of the workpiece to be welded; Turning on the TIG power switch of the ultra-long TIG arc welding machine, so that the TIG long arc reaches the bottom of the narrow gap groove of the workpiece to be welded with the help of the laminar plasma to start the arc; The robot arm is used to clamp and drive the super-long TIG arc welding gun to move along the center line of the groove from the starting position of the workpiece to be welded to the end position of the workpiece to be welded; during the mobile welding process, the non-transferred arc power switch and the TIG power switch are always in the on state; Repeat the above steps according to the thickness of the workpiece to be welded, and perform narrow gap single-pass multi-layer welding until the narrow gap groove is filled; The wire diameter is 1.2 mm, the plate thickness is 20-60 mm, the arc length is 20-60 mm; the groove gap is 6 mm -20 mm; The wire feeding speed is 10-40 mm / s, the welding speed is 0.5-4 mm / s, the ion gas flow rate is 0.5-5 L / min, the shielding gas flow rate is 5-25 L / min, and the height of the super-long TIG arc welding gun from the upper surface of the workpiece to be welded is 1-3 mm.

2. The ultra-long TIG arc narrow gap welding device according to claim 1, characterized in that: The ultra-long TIG arc narrow gap welding device also includes: Wire feeder; A wire feeding tube, the wire feeding tube is connected to the wire feeding machine; the wire feeding tube is obliquely arranged on one side of the super-long TIG arc welding gun; the wire feeding tube moves synchronously with the super-long TIG arc welding gun; A workbench is arranged below the extra-long TIG arc welding gun and is used for placing the workpiece to be welded; the extra-long TIG arc welding gun is located above the workpiece to be welded and can move in the horizontal direction of the narrow gap of the workpiece to be welded.

3. The ultra-long TIG arc narrow gap welding device according to claim 2, characterized in that: The ultra-long TIG arc narrow gap welding device also includes a clamping mechanism, which is arranged on one side of the ultra-long TIG arc welding gun and is used to clamp the wire feeding tube; the angle between the wire feeding tube and the tungsten electrode is 45°.

4. The ultra-long TIG arc narrow gap welding device according to claim 1, characterized in that: The super-long TIG arc welding machine and the super-long TIG arc welding gun both have a cooling water channel, and the water inlet and the water outlet of the cooling water channel are used to be connected to a water cooling system.

5. The ultra-long TIG arc narrow gap welding device according to claim 1, characterized in that: The ultra-long TIG arc narrow gap welding device comprises: A camera, wherein the camera is arranged on one side of the extra-long TIG arc welding gun, the lens of the camera is arranged relative to the groove gap of the workpiece to be welded; the lens of the camera is horizontal to the workpiece to be welded, and the distance between the lens of the camera and the extra-long TIG arc welding gun is greater than or equal to 20 cm; the camera is connected to the extra-long TIG arc welding gun through a clamp so as to move synchronously with the extra-long TIG arc welding gun; the camera is used to be connected to a computer.

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