Welding apparatus and welding method

Abstract

To provide a welding device and a welding method capable of suppressing welding defects of hot wire TIG build-up welding.SOLUTION: A welding apparatus 100 receives, from a camera 10, images of: a wire 5; a wire feeding tip 6 that feeds the wire 5; a base material (welding target material 3); and a TIG electrode 2 that generates an arc. The welding apparatus 100 analyzes the images and measures a wire length indicating a length from a tip end of the wire 5 to a tip end of the wire feeding tip 6. The welding apparatus 100 controls a height of the wire 5 so that the wire length falls within a predetermined range (Lmin32 to Lmax33), and brings the wire 5 into contact with an arc-melted base metal (molten pool 7), so as to cause current supplied to the wire 5 to melt the wire 5.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a welding apparatus and a welding method.

Background Art

[0002] A metal cask is a sealed cylindrical container (material: carbon steel) for storing used nuclear fuel. In order to store used nuclear fuel for a long period of time, it has a structure in which a stainless steel sheet surface is formed between the side surface of the inner circumference of the cylindrical container and a plurality of lids. Stainless steel wires are overlay welded on these sheet surfaces to enhance corrosion resistance. By applying the hot wire TIG welding method with high welding efficiency to these overlay welding locations, the overlaying efficiency has been improved to 4 to 6 times that of conventional TIG welding, and a significant reduction in man-hours has been achieved.

[0003] However, after overlay welding, when the overlay welded portion is machined to a predetermined dimension, welding defects may occur on the sheet processed surface. When repairing these welding defects, local welding deformation occurs, so it is necessary to perform machining on the sheet surface again after repair welding. In order to obtain a welding metal part with high efficiency and high quality, a reasonable and highly reliable welding method is required.

[0004] For example, in Patent Document 1 (Japanese Patent Laid-Open No. 2002-239731), as hot wire TIG welding, the insertion state of the added wire into the welded portion is monitored by a camera, and the image captured by this camera is analyzed by an image processing device to determine the presence or absence of vibration and the degree of bending of the added wire. When vibration or bending is detected, the applied power by the wire heating power source is increased to automatically control so that the heating amount for the added wire increases. Further, when vibration of the added wire is detected and it is determined that the heating amount by the wire heating power source is appropriate, a method is disclosed in which the wire torch is appropriately moved by a driving mechanism such as a wire torch tilting mechanism to automatically control the insertion position of the added wire into the welded portion closer to the arc side.

[0005] Furthermore, Patent Document 2 (JP 2002-120066) discloses a welding sensor that can estimate the three-dimensional positions of the welding area and groove, such as the welding wire tip position and molten pool, as well as the welding area, for consumable electrode automatic welding (hereinafter referred to as MAG / MIG welding), and can be used to perform proper groove tracing welding and adjust welding conditions. The welding torch is equipped with a laser projector and an imaging mechanism in front of the welding direction, an imaging device that includes an image processing mechanism in addition to the imaging mechanism, and a computing device, which forms an optical section image of the welding area in front of the welding direction, and the imaging device acquires an image in real time in which the welding wire extending from the welding torch, the molten pool, and the optical section image located in front of the welding area are captured on a single screen, and the spatial position information of the optical section image and the welding wire is determined using the spatial position information of the plane including the axis of the welding torch and the laser beam scanning plane, and the information of the acquired image.

[0006] Furthermore, Patent Document 3 (JP 2000-301340) discloses an automatic welding apparatus for non-consumable electrode TIG automatic welding, in which a monitoring camera is installed on the welding head, and information such as the electrode tip position, wire tip position, groove position, and molten pool captured by the monitoring camera is input to a control device, and welding conditions are corrected based on the control signal output from the control device, wherein a wavelength-independent attenuation filter with partially different transmittance distributions and a narrowband filter are arranged in front of the monitoring camera. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2002-239731 [Patent Document 2] Japanese Patent Publication No. 2002-120066 [Patent Document 3] Japanese Patent Publication No. 2000-301340 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The aforementioned Patent Document 1 describes a hot wire welding method in which the insertion state of the additive wire into the weld area is monitored by a camera, and the images captured by this camera are analyzed by an image processing device, but only the presence or absence of vibration and the degree of bending of the additive wire are detected. Furthermore, if vibration of the additive wire is detected, a control method is provided to increase the amount of heating by the wire heating power supply and to move the wire torch appropriately using a drive mechanism such as a wire torch tilting mechanism, thereby automatically controlling the insertion position of the additive wire into the weld area to be closer to the arc side. It is claimed that this method can reliably correct the bending tendency of the additive wire during high-speed welding, thus avoiding welding defects caused by bending of the additive wire without depending on the welder. However, it does not mention at all the optimal range of conditions that exist between the amount of heat input of the arc, the TIG electrode position, the target position of the wire tip, and the boundary line between the previous layer weld bead, which are the main causes of welding fusion defects.

[0009] Furthermore, Patent Document 2 describes how the three-dimensional spatial positions of the welding area and groove, including the tip position of the MAG / MIG welding wire and the molten pool, are determined using a laser projector, imaging mechanism, image processing mechanism, and computing device. However, it does not describe non-consumable TIG hot wire welding. Moreover, it does not mention any measures to suppress welding fusion defects or melting defects.

[0010] Furthermore, Patent Document 3 describes an automatic welding device for non-consumable electrode TIG automatic welding, which is equipped with a monitoring camera on the welding head, inputs information such as the electrode tip position, wire tip position, groove position, and molten pool captured by the monitoring camera into a control device, and corrects the welding conditions based on the control signal output from the control device. It is assumed that symmetrical TIG automatic welding is performed with one layer and one pass, with the electrode position at the center of the groove, based on the electrode target position calculated from the positions of both shoulders of the groove, but there is no description of hot wire TIG overlay welding, which is performed with multiple layers and multiple passes, resulting in an asymmetrical weld bead relative to the TIG electrode.

[0011] Furthermore, Patent Document 3, focusing on butt groove welding, states that in a method for reducing welding defects, if the misalignment between the TIG electrode and the wire target position is not zero, the wire's left-right position is corrected according to that misalignment. Also, if a change in the shape of the leading edge of the molten pool is recognized as a welding abnormality, welding is stopped to reduce the occurrence of welding defects. However, in hot wire TIG overlay welding, where an asymmetrical weld bead is formed relative to the TIG electrode in multiple layers and multiple passes, if the wire target position and the TIG electrode position are in the same position, the heat of the welding arc is absorbed by the added wire, and the bottom of the molten pool cannot melt at the location of the poorly shaped leading layer weld bead, resulting in a problem of poor fusion. In addition, during normal welding, the leading edge of the molten pool is concave near the wire feeding position. Patent Document 3 judges such a shape of the leading edge of the molten pool as an abnormal shape, and therefore does not mention overlay welding when the leading edge of the molten pool is concave.

[0012] The object of the present invention is to provide a welding apparatus and a welding method that can suppress welding defects in hot wire TIG overlay welding. [Means for solving the problem]

[0013] To achieve the above objective, an example welding apparatus of the present invention receives images of the wire, a wire feeding tip that feeds the wire, a base material, and a TIG electrode that generates an arc from a camera, analyzes the images to measure the wire length, which is the length from the tip of the wire to the tip of the wire feeding tip, controls the height of the wire so that the wire length is within a predetermined range, brings the base material molten by the arc into contact with the wire, and melts the wire with the current supplied to the wire. A welding apparatus that analyzes the image to recognize the tip of the TIG electrode, the tip of the wire, and the boundary line of the weld bead of the previous pass, controls the lateral position of the tip of the TIG electrode to be within ΔY=W / 3 (W: weld bead width) from the boundary line, controls the lateral position of the tip of the wire to be within ΔY from the tip of the TIG electrode, and satisfies |D1-D2|≧d (d: wire diameter) between the lateral distance D1 from the boundary line to the tip of the TIG electrode and the lateral distance D2 from the tip of the TIG electrode to the tip of the wire. . [Effects of the Invention]

[0014] According to the present invention, welding defects in hot-wire TIG overlay welding can be suppressed. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

Brief Description of the Drawings

[0015] [Figure 1] This is an example of hot wire TIG surfacing welding of stainless steel. [Figure 2] This is a schematic diagram of a moving image example of the welding torch, molten pool, and aiming position of the wire tip (aimed to the left of the TIG tip). [Figure 3] This is a schematic diagram of a moving image example of the welding torch, molten pool, and aiming position of the wire tip (aimed to the right of the TIG tip). [Figure 4] This is an example of hot wire TIG surfacing welding of stainless steel (appropriate wire height). [Figure 5] This is an example of hot wire TIG surfacing welding of stainless steel (high wire height). [Figure 6] This is an example of hot wire TIG surfacing welding of stainless steel (low wire height). [Figure 7] This is an example of measuring the length of the wire during the welding process. [Figure 8] This is an example of hot wire TIG multi-pass surfacing welding of stainless steel (without welding defects). [Figure 9] This is an example of hot wire TIG multi-pass surfacing welding of stainless steel (with welding defects). [Figure 10] This is an example of hot wire TIG surfacing welding at the corner of the groove (without welding defects). [Figure 11] This is an example of hot wire TIG surfacing welding at the corner of the groove (with welding defects). [Figure 12] This is an example of hot wire TIG multi-pass surfacing welding inside the groove. [Figure 13A] This is a diagram showing the positional relationship between the TIG electrode and the wire. [Figure 13B] This is a diagram showing the positional relationship between the TIG electrode and the wire. [Figure 13C] This is a diagram showing the positional relationship between the TIG electrode and the wire. [Figure 14A] This is a diagram showing the positional relationship between the TIG electrode and the wire. [Figure 14B] This diagram shows the positional relationship between the TIG electrode and the wire. [Figure 14C] This diagram shows the positional relationship between the TIG electrode and the wire. [Modes for carrying out the invention]

[0016] The following describes a hot wire TIG overlay welding method, which is an example of the present invention, based on the illustrated Examples 1 to 5.

[0017] (Example 1) Figure 1 shows an example of hot-wire TIG overlay welding of stainless steel applied to a workpiece 3. Although the welding machine and wire heating power supply are omitted in Figure 1, the wire 5 (welding wire) is fed from the front of the welding torch 1, and a camera 10 (observation welding camera) is installed between the welding torch 1 and the wire feeding tip 6. The camera's orientation is set so that the lower end of the welding torch 1, the tip of the TIG electrode 2, and the tip of the wire feeding tip 6 can be captured simultaneously. A high-resolution camera 10 is used. A light-shielding filter 9 is installed in front of the camera 10 to suppress the effect of the strong light of the welding arc 4 to a certain extent, or to obtain a clear image of the molten pool 7 and the weld bead of the previous pass due to the light of the welding arc 4. The opening and closing of the light-shielding filter 9 is linked to the presence or absence of the welding arc 4.

[0018] Immediately before welding begins, the welder sets the welding torch 1 to the welding start position. The tip position 25 of the TIG electrode 2 and the boundary lines 171 and 172 of the previous pass weld bead are analyzed by the image processing device 11 immediately before welding begins (see Figure 2). The obtained position information of the TIG electrode and the boundary lines of the previous pass weld bead is then used for position image analysis of the TIG electrode tip position 25 and the boundary lines of the previous pass weld bead after the arc starts.

[0019] Next, immediately before starting welding, a light-shielding filter 9 is placed in front of the camera 10, and then a welding arc 4 (arc) is generated. When the welding arc 4 transitions from the starting current to the main welding current and stabilizes, the AVC function of the welding machine is used to keep the height of the TIG electrode 2 constant. The molten pool 7 also expands, and the wire 5 is fed into the molten pool 7. When the wire 5 comes into contact with the molten pool 7, the wire is heated by current. Meanwhile, when transitioning from the starting current to the main welding current, the timing of the welding trolley's start is controlled so that the molten pool does not become too large, and then welding begins.

[0020] In the short time between the start of welding and the establishment of stable welding, the welder adjusts the target position 51 (feeding position) of the wire 5 tip using the wire drive mechanism 12 to ensure stable feeding of the wire 5 into the molten pool 7. Afterward, the welder switches the control device 13 to automatic monitoring mode and performs welding. It is also possible to switch from automatic monitoring mode to manual welding mode during welding.

[0021] Figure 2 shows a schematic diagram of video image example 15 of the welding torch 1, molten pool 7, wire feeding tip 6, and the target position a1 of the wire tip (targeted to the left of the tip of the TIG electrode 2) as captured by camera 10. Figure 3 shows a schematic diagram of video image example 15 of the welding torch 1, molten pool 7, wire feeding tip 6, and the target position a1 of the wire tip (targeted to the right of the tip of the TIG electrode 2) as captured by camera 10.

[0022] Although the tip b5(25) of the TIG electrode 2 is not directly detected, the image processing device 11 can identify the electrode's feature points b1(21), b2(22) to b4(24), and estimate the electrode's tip position 25(b5).

[0023] Simultaneously, the image processing device 11 detects the positions of the feature points a1 (target position 51 at the wire tip) to atip (position 54 at the tip of the wire feeding tip) of the wire 5, the boundary lines 171 and 172 of the weld bead 17 from the previous pass immediately before welding, and the boundary lines 71 and 72 of the weld bead after welding. The image processing device 11 also calculates the amount of deviation 19 between the tip position 25 of the TIG electrode 2 and the target position 51 at the wire tip, the distance from the target position 51 at the wire tip to the wire feeding tip 6 (wire length 26), the amount of deviation 16 between the tip position 25 of the TIG electrode 2 and the boundary line 171 of the weld bead 17 from the previous pass, the amount of deviation 18 between the boundary line 71 of the weld bead after welding and the boundary line 171 of the weld bead 17 from the previous pass, and the molten bead width 20.

[0024] The tip position 25 of the TIG electrode 2 and the target position 51 of the wire tip, set by the welder at the initial stage of welding, are used as standard welding conditions. Next, the variation of the tip position 25 of the TIG electrode 2 and the target position 51 of the wire tip due to these standard welding conditions is calculated, and the control device 13 corrects the tip position 25 of the TIG electrode and the target position 51 of the wire tip, thereby enabling stable automatic welding.

[0025] The heat input distribution of a TIG arc is a normal distribution, with a high energy density in the center of the arc and a decrease in energy density towards the outer edge of the molten pool. In the region with an arc energy density of 80%, the workpiece 3 and wire 5 are sufficiently melted, and no fusion defects 34 occur. Therefore, with respect to the weld bead width W(20) obtained after welding, the amount of deviation 19 (maximum allowable value) of the target position 51 of the wire tip relative to the position of the TIG electrode 2 at the center of the weld bead can be expressed by the following formula.

[0026]

number

[0027] A good weld bead can be obtained by adjusting the target position 51 of the wire tip in the left-right direction within the range of -ΔY to +ΔY. On the other hand, the length 26 of the wire 5 can be detected, and the height variation of the wire 5 can be adjusted by controlling the length 26 of the wire 5.

[0028] Figures 4 to 6 show examples of hot-wire TIG overlay welding of stainless steel applied to the workpiece 3. The figures show the TIG welding power supply 28 and the wire heating power supply 27. Figure 4 shows that the target position 51 of the wire tip is inserted into the molten pool 7 and the wire 5 is fed normally. As shown in Figure 5, if the height of the wire 5 fluctuates significantly, the wire length 26 is detected as long, and the target position 51 of the wire tip is too close to the tip position 25 of the TIG electrode 2, causing the target position 51 of the wire tip to melt too much and become spherical. Also, the wire tip does not contact the molten pool, and current cannot be supplied to the hot wire. In this case, the molten pool becomes abnormal, the bead width after welding fluctuates significantly, and the weld bead may meander. When performing layer welding in meandering areas, the risk of fusion failure increases. Although not shown, if the height of the wire 5 becomes even higher, the wire length 26 becomes longer than in the video image 15, and there is a risk that the wire 5 will come into contact with the TIG electrode 2. Just before the wire length 26 exceeds the limit value, the wire drive mechanism 12 (wire drive device) controls the target position 51 of the wire tip to a lower position, thereby suppressing the risk of the wire 5 coming into contact with the TIG electrode 2, and allowing welding to continue without interruption.

[0029] On the other hand, as shown in Figure 6, if the height of the wire 5 fluctuates downwards in the vertical direction, the length of the wire 26 in the image becomes shorter, and the target position 51 of the wire tip cannot be properly inserted into the molten pool 7, causing welding to be interrupted.

[0030] In hot-wire TIG overlay welding of stainless steel, there is an optimal range for wire length 26. Welding is performed while constantly controlling the wire length 26 within this optimal range.

[0031] Figure 7 shows an example of measuring the wire length 26 during the welding process. At the time interval 29 before welding begins, the welder adjusts the target position 51 of the wire tip using the wire drive mechanism 12 and feeds the wire 5 stably into the molten pool 7 until stable welding can be performed. At time t1, the welder switches the control device 13 to automatic monitoring mode. The control device 13 monitors that the appropriate wire length 26 is within the range of Lmin32 to Lmax33. At times t2 and t3, when an abnormality in the wire length 26 occurs, a good weld bead is obtained by controlling the wire length 26 to a constant value (the average value of Lmin32 and Lmax33).

[0032] Figure 8 shows an example of multi-pass hot wire TIG welding of stainless steel on a flat workpiece 3. Although fusion defects are said to be likely to occur at the boundary of the weld bead, in this embodiment, in order to obtain a good weld with sufficient build-up efficiency and no welding defects, the displacement amount 16 between the tip position 25 of the TIG electrode 2 and the boundary line 172 of the weld bead 17 of the previous pass is set to 0 to ±ΔY1 (if the position vector of the TIG electrode 2 is Y1, then -ΔY1≦Y1≦ΔY1). The displacement amount 19 between the tip position 25 of the TIG electrode 2 and the target position 51 of the wire tip is set to 0 to ±ΔY2 (if the position vector of the target position 51 of the wire tip is Y2, then -ΔY2≦Y2≦ΔY2). Furthermore, the displacement amount 51 of the wire tip is set to be greater than or equal to the wire diameter d (distance from the boundary line to the target position of the wire tip = |Y1+Y2|) so that it does not overlap with the boundary line 172 (molten boundary line) of the previous bead.

[0033] Figures 13A-13C show the positional relationship when TIG electrode 2 is positioned to the right of the boundary line of the previous pass weld bead, and Figures 14A-14C show the positional relationship when TIG electrode 2 is positioned to the left of the boundary line of the previous pass weld bead. In the figures, D1 and D2 represent the magnitudes |Y1| and |Y2| of the position vectors Y1 and Y2, respectively.

[0034] In Figures 13A and 14A, the tip position 25 of the TIG electrode 2 is rarely less than the wire diameter d from the boundary line, so the frequency of |Y1+Y2|≧d is high, and the probability of welding defects occurring is low.

[0035] In Figures 13B and 14B, for |Y1+Y2|≧d to be satisfied, it is necessary that D1-D2≧d. In Figures 13C and 14C, for |Y1+Y2|≧d to be satisfied, it is necessary that D2-D1≧d. Therefore, in order to suppress welding defects, it is especially important to satisfy equation (4).

[0036]

number

[0037]

number

[0038]

number

[0039] Table 1 shows an example of the welding conditions for this embodiment.

[0040] [Table 1]

[0041] The main features of Example 1 can also be summarized as follows:

[0042] The welding apparatus 100 shown in Figure 1 receives images from the camera 10 of the wire 5, the wire feed tip 6 that feeds the wire 5, the base material (workpiece 3), and the TIG electrode 2 that generates the arc. The welding apparatus 100 analyzes the images and measures the wire length, which is the distance from the tip of the wire 5 to the tip of the wire feed tip 6. The welding apparatus 100 controls the height of the wire 5 so that the wire length is within a predetermined range (Lmin 32 to Lmax 33, Figure 7), brings the wire 5 into contact with the base material (molten pool 7) melted by the arc, and melts the wire 5 with the current supplied to the wire 5.

[0043] This suppresses fluctuations in bead width after welding and prevents the weld bead from meandering. As a result, welding defects in hot wire TIG overlay welding can be suppressed. The welding apparatus 100 stores, for example, an image of the wire 5 of a standard length (predetermined length) corresponding to the position and orientation of the camera 10 as a template in a storage device, and measures the wire length by comparing the image received from the camera 10 with the template.

[0044] The welding apparatus 100 analyzes the image to recognize the tip of the TIG electrode 2, the tip of the wire 5, and the boundary line (171, 172) of the previous pass weld bead. The welding apparatus 100 controls the lateral position of the tip of the TIG electrode 2 to be within ΔY = W / 3 (W: weld bead width) from the boundary line (171, 172). The welding apparatus 100 controls the lateral position of the tip of the wire 5 to be within ΔY from the tip of the TIG electrode 2. The lateral distance D1 from the boundary line (171, 172) to the tip of the TIG electrode 2 and the lateral distance D2 from the tip of the TIG electrode 2 to the tip of the wire 5 satisfy |D1-D2|≧d (d: wire diameter). That is, it is preferable that the lateral position of the tip of the wire 5 is at least the wire diameter d away from the boundary line (171, 172). This makes it possible to suppress fusion defects near the boundary line of the weld bead.

[0045] The welding apparatus 100 detects characteristic points of the TIG electrode 2 from the image and estimates the position of the tip of the TIG electrode from the characteristic points. This makes it possible to determine the position of the tip of the TIG electrode 2 even if the tip of the TIG electrode 2 is not recognized from the image due to the arc or the like.

[0046] In this embodiment, the welding apparatus 100 consists of an image processing apparatus 11 and a control device 13. The image processing apparatus 11 and the control device 13 are composed of, for example, a processor such as a CPU (Central Processing Unit), a storage device such as memory, an input device such as a keyboard, a display device such as a display, and a communication device such as a network interface. In this embodiment, the image processing apparatus 11 and the control device 13 are separate components, but they may be integrated.

[0047] The image processing device 11 receives images of the wire 5, wire feeding tip 6, base material (workpiece 3), and TIG electrode 2 from the camera 10. The image processing device 11 analyzes the images and measures the wire length. The image processing device 11 transmits the wire length to the control device 13. The control device 13 receives the wire length from the image processing device 11. The control device 13 controls the height of the wire 5 so that the wire length is within a predetermined range (Lmin 32 to Lmax 33, Figure 7), brings the wire 5 into contact with the base material (molten pool 7) melted by the arc, and melts the wire 5 with the current supplied to the wire 5.

[0048] The image processing device 11 performs image analysis, which improves the throughput of the welding device 100, for example.

[0049] (Example 2) As shown in Figure 9, the target position 51 of the wire tip overlaps with the boundary line 172 (melting boundary line) of the previous bead. When the amount of wire 5 fed is large, the heat input of the welding arc 4 (TIG welding arc) is consumed in melting the wire 5, and the amount of heat input to melt the boundary line 172 of the previous layer weld bead decreases, resulting in a fusion defect 34 near the boundary line 172 (melting boundary line) of the weld bead. Furthermore, even if the misalignment amount 19 between the tip position 25 of the TIG electrode 2 and the target position 51 of the wire tip is set to 0 mm, the risk of welding defects increases. In this embodiment, when the misalignment amount between the target position 51 of the wire tip and the boundary line 172 (melting boundary line) of the previous bead is 0 mm, a fusion defect 34 (welding defect) occurs.

[0050] (Example 3) Figure 10 shows an example of multi-pass hot wire TIG buildup welding of stainless steel applied to the workpiece 3 described above within a groove. The welding torch 1 is tilted at an angle of 35 (welding torch angle), and for buildup welding on the groove wall side, the displacement amount 16 between the tip position 25 of the TIG electrode 2 and the boundary line 171 of the previous pass weld bead 17 is set to 0 to -ΔY1 in order to suppress melting defects. The displacement amount 19 between the tip position 25 of the TIG electrode 2 and the target position 51 of the wire tip is set to 0 to +ΔY2. Furthermore, the target position 51 of the wire tip is set to a displacement amount greater than or equal to the wire diameter d so that it does not overlap with the boundary line 171 (melting boundary line) of the previous bead.

[0051] (Example 4) As shown in Figure 11, the target position 51 of the wire tip overlaps with the boundary line 171 (melting boundary line) of the previous bead. When the amount of wire 5 fed increases, the heat input of the welding arc 4 is consumed in melting the wire 5, and the amount of heat used to melt the boundary line 171 of the previous layer weld bead decreases, making it easier for fusion defects 34 to occur between the weld beads.

[0052] If the displacement 16 between the tip position 25 of the TIG electrode and the boundary line 171 of the previous pass's weld bead 17 is set to 0 to -ΔY1, and the displacement 19 between the tip position 25 of the TIG electrode and the target position 51 of the wire tip is set to 0 to -ΔY2, then the difference between the displacement 16 and the displacement 19 (|D1-D2|) becomes smaller than the wire diameter, resulting in a fusion failure 34 (welding defect).

[0053] (Example 5) Figure 12 shows an example of multi-pass hot wire TIG welding of stainless steel applied to the workpiece 3 described above within a groove. Welding is first performed on the corners of the groove wall (weld beads 37 and 38), and then multi-pass hot wire TIG welding of stainless steel (weld bead 39) is performed on the flat workpiece 3 shown in Figure 8. Finally, welding is performed on the weld bead 40.

[0054] When welding the first layer, the corners of the groove wall are rounded, which reduces the risk of fusion failure. However, in subsequent layers of welding, the shape of the groove wall corners is not stable, so welding is first performed on both corners using the construction conditions shown in the example described above. When welding the groove wall corners last, the angle (35) of the welding torch 1 and the setting of the electrode tip position 25 may be limited by the influence of the groove wall and the adjacent previous weld bead, which increases the risk of fusion failure at the groove corners.

[0055] By performing welding in the order shown in Figure 12—weld bead 37 → weld bead 38 → weld bead 39 → weld bead 40—fusing defects in the groove wall can be suppressed.

[0056] Within the welding condition range shown in Table 1, welding is performed such that the bottom width of the final weld bead 40 before welding is 2d to 0.8W, based on the groove width and the overlap width of weld beads 37, 38, and 39.

[0057] If the pre-weld bead width of the final weld bead 40 is 2d to 5d, the tip position 25 of the TIG electrode 2 is set to aim at the center of the pre-weld bead width of the final weld bead 40. The offset amount 19 between the tip position 25 of the TIG electrode and the target position 51 of the wire tip is set to 0 mm so that the target position 51 of the wire tip does not overlap with the melting boundary line (372 and 391) of the previous bead.

[0058] If the pre-weld bead width of the final weld bead 40 is 5d to 0.8W, the tip position 25 of the TIG electrode 2 is set to aim at the center of the pre-weld bead width of the final weld bead 40. The target position 51 of the wire tip is set to a displacement of at least the wire diameter d so that it does not overlap with the boundary lines 372 and 391 (molten boundary lines) of the previous bead.

[0059] The main features of Example 5 can also be summarized as follows. Below, we will explain by focusing on the second layer (weld beads 37, 38, 39, 40) in Figure 12 as an example.

[0060] The welding apparatus 100 performs a first build-up weld (weld bead 37) on one corner of the groove. The welding apparatus 100 performs a second build-up weld (weld bead 38) on the other corner of the groove. The welding apparatus 100 performs a k-th build-up weld (k: 3, 4, ..., N) in the direction away from the other corner of the groove until the bead bottom width, which indicates the distance between the first build-up weld and the Nth (N: integer of 3 or more) build-up weld, is 2d to 0.8W (d: wire diameter, W: weld bead width).

[0061] If the bead bottom width is 2d to 5d (narrow), the welding apparatus 100 sets the lateral position of the tip of the TIG electrode 2 to the center of the bead bottom width, sets the lateral position of the tip of the wire 5 to the same position as the lateral position of the TIG electrode 2, and performs the N+1th buildup welding.

[0062] On the other hand, if the bead bottom width is 5d to 0.8W (wide), the welding apparatus 100 positions the tip of the wire 5 laterally at a distance of at least the wire diameter d from the boundary line 372 of the first overlay weld (weld bead 37) on the TIG electrode 2 side, and at least the wire diameter d from the boundary line 391 of the Nth overlay weld (weld bead 39) on the TIG electrode 2 side, and performs the N+1th overlay weld.

[0063] This makes it possible to suppress fusion defects near the boundary line of the weld bead in the groove.

[0064] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are included. For example, the embodiments described above are described in detail to make the present invention easier to understand, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace parts of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add configurations from other embodiments to the configuration of one embodiment. In addition, it is possible to add, delete, or replace parts of the configuration of each embodiment with other configurations.

[0065] Furthermore, some or all of the above configurations and functions may be implemented in hardware, for example, by designing them as integrated circuits. Alternatively, the above configurations and functions may be implemented in software by having the processor interpret and execute programs that implement each function. Information such as programs, tables, and files that implement each function can be stored in memory, a recording device such as a hard disk or SSD (Solid State Drive), or a recording medium such as an IC card, SD card, or DVD.

[0066] The embodiments of the present invention may also be in the following forms.

[0067] In the following embodiments, by monitoring the position of the non-consumable electrode, the target position of the hot wire, the melting width of the molten pool, the target position of the wire tip, and the length of the wire from the wire feeding tip to the wire tip from the image, and in particular keeping the wire length within a predetermined range, the wire can be stably fed into the molten pool, or the shape of the previous layer weld bead can be detected by the same image processing, and it can be confirmed that the edge of the previous layer bead is completely melted, thereby providing a stable welding heat input and resulting in a weld bead without welding defects. Furthermore, the present invention provides a welding method and working condition range characterized by automatically adjusting each welding condition within the optimal working condition range during the welding process, thereby obtaining a good weld.

[0068] (1) In non-consumable electrode hot wire welding of stainless steel, a welding camera is installed between the TIG electrode and the wire feeding tip to perform image analysis of the non-consumable electrode, the wire supplied from the wire supply device from the front, the molten pool, and the toe of the previous layer bead near the position of the non-consumable electrode. A non-consumable electrode hot wire welding control method is characterized by detecting fluctuations in the length from the tip of the wire feeding tip to the tip of the wire, and by inserting the tip of the wire into the molten pool, thereby supplying the wire without interrupting the hot wire current. Furthermore, the welder can arbitrarily switch from automatic monitoring mode to manual welding mode, and from manual welding mode to automatic monitoring mode during welding.

[0069] (2) A welding method characterized by obtaining a good weld without fusion defects, in the non-consumable electrode hot wire welding described in (1), wherein the TIG electrode position, the target position of the wire tip, and the boundary line between weld beads are set to the following relationship: where ΔY=W / 3, ΔY1=ΔY, ΔY2=ΔY, |D1-D2|≧d, W: weld bead width, ΔY: allowable amount of the target position of the wire tip in the left and right directions from the center of the electrode, ΔY1: amount of deviation (allowable amount) between the tip position of the TIG electrode and the boundary line of the weld bead of the previous pass, ΔY2: amount of deviation (allowable amount) between the tip position of the TIG electrode and the target position of the wire tip, D1: amount of deviation between the tip position of the TIG electrode and the boundary line of the weld bead of the previous pass, D2: amount of deviation between the tip position of the TIG electrode and the target position of the wire tip, and d: wire diameter.

[0070] (3) In the non-consumable electrode hot wire welding described in (1), the displacement between the tip position of the TIG electrode and the boundary line of the weld bead of the previous pass is set to 0 to ±ΔY1. The displacement between the tip position of the TIG electrode and the target position of the wire tip is set to 0 to ±ΔY2. Furthermore, the welding conditions range is set so that the target position of the wire tip does not overlap with the melting boundary line of the previous bead by a displacement of d or more.

[0071] (4). In the non-consumable electrode hot wire groove buildup welding described in (1), in order to suppress poor fusion at the corners of the groove wall, for the second and subsequent layers of welding, the corners of the groove are welded first, and then the welding inside the groove is performed. Based on the width of the groove, the width of the weld bead, and the overlap width between the weld beads, welding is performed so that the bottom width of the final weld bead 40 before welding is 2d to 0.8W. If the bottom width of the final weld bead before welding is 2d to 5d, the tip position of the TIG electrode is set to aim at the center of the aforementioned bottom width. The target position 51 of the wire tip is set to 0 mm, so that it does not overlap with the melting boundary line of the previous bead. If the bottom width of the bead is 5d to 0.8W, the welding conditions range is set so that the target position of the wire tip does not overlap with the melting boundary line of the previous bead, by setting a deviation of d or more than the wire diameter.

[0072] (1)-(4) can be rephrased as follows:

[0073] This embodiment provides a welding method for multi-layer, multi-pass hot-wire TIG overlay welding of stainless steel, in which the TIG electrode position, the target position of the wire tip, and the boundary line between the previous weld beads are analyzed using image analysis. When welding with a certain constant welding heat input, the TIG electrode position, the target position of the wire tip, and the boundary line between the weld beads are set to always have a constant relationship, thereby preventing welding fusion defects.

[0074] This embodiment first involves a grooving step in which a groove is machined or grooved on the base material surface to create a groove bevel in multi-layer, multi-pass hot wire TIG overlay welding of stainless steel, and then a monitoring camera is placed in front of the hot wire TIG overlay welding torch between the welding torch and the wire feeding tip to perform molten pool image analysis during welding to determine the TIG electrode position, the target position of the wire tip, the boundary line of the weld bead of the previous pass immediately before welding, and the boundary line of the weld bead after welding. The amount of deviation between the TIG electrode position and the target position of the wire tip, the distance from the wire tip to the wire feeding tip, and the distance between the wire tip and the previous pass The welding method includes the steps of calculating the amount of deviation from the boundary line of the weld bead and the amount of deviation between the boundary line of the weld bead after welding and the boundary line of the weld bead of the previous pass, setting the TIG electrode position and wire feeding position within a pre-set optimal working condition range, monitoring fluctuations in the TIG electrode position and wire feeding position during the welding process, and adjusting the TIG electrode position in the left-right direction and the wire target position in the up-down direction using a fine adjustment mechanism before deviating from the working condition range, and setting the TIG electrode position near the boundary line of the weld bead of the previous pass, and performing welding so that the target position of the wire tip does not overlap with the boundary line of the weld bead of the previous pass. The welding method is characterized in that the position of the boundary line of the weld bead after welding is wider than the boundary line of the weld bead of the previous pass, so that no melting defects occur and a good weld is obtained.

[0075] This enables high-efficiency, fusion-free welds in hot-wire TIG overlay welding of stainless steel. It also reduces welding time and repair welding costs, and automatically monitors fluctuations in TIG electrode position and wire feeding position during the welding process, ensuring welding without deviations from appropriate working conditions. Furthermore, one welder can operate two or more welding machines, improving production efficiency and reducing workload. [Explanation of Symbols]

[0076] 1... Welding torch 2...TIG electrode 3…Material to be welded 4…Welding arc 5…Wire (welding wire) 6…Wire feeding tip 7…Melting pool 8. Weld metal after solidification 9… Light-blocking filter 10...Camera (welding camera) 11…Image processing device 12…Wire drive mechanism 13…Control device 14…Welding direction 15…Videos and images 16…Amount of displacement between the TIG electrode and the boundary line of the weld bead from the previous pass. 17... Weld bead of the previous pass 18... Amount of deviation between the boundary line 71 of the weld bead after welding and the boundary line of the weld bead of the previous pass. 19…The amount of deviation between the tip position of the TIG electrode and the target position of the wire tip. 20... Molten bead width 21… Electrode characteristic point b1 22… Electrode characteristic point b2 23… Electrode characteristic point b3 24… Electrode characteristic point b4 25…Tip position of the TIG electrode (feature point b5) 26…Wire length 27... Wire heating power supply 28...TIG welding power supply 29…Welding start time interval (t0~t1) 30...Automatic correction at time t2 when the wire length is shortened. 31...Automatic correction at time t3 when the wire length increases 32…Lower limit of appropriate wire length 33…Upper limit of appropriate wire length 34…Poor fusion 35...Angle (welding torch angle) 36…Bevel angle 37...Weld bead on the left side of the groove wall of the second layer 38...Weld bead on the right side of the groove wall of the second layer 39...Continuing weld bead for the second layer 40...Final weld bead of the second layer 51…Characteristics of the wire a1 52…Characteristics of the wire a2 53…Characteristics of wire an 54…Characteristics of the wire atip 71... Left boundary line of weld bead 7 after welding 72...Right boundary line of weld bead 7 after welding 161...Amount of deviation between the tip of the TIG electrode and the boundary line 372 of the weld bead of the previous pass. 162... The amount of deviation between the tip of the TIG electrode and the boundary line 391 of the weld bead of the previous pass. 171... Left boundary line of weld bead 17 of the previous pass 172... Right boundary line of weld bead 17 of the previous pass 371... Left boundary line of weld bead 37 372...Right boundary line of weld bead 37 381... Left boundary line of weld bead 38 391... Left boundary line of weld bead 39

Claims

1. A welding apparatus that receives images from a camera of a wire, a wire feeding tip for feeding the wire, a base material, and a TIG electrode for generating an arc, analyzes the images to measure the wire length, which is the length from the tip of the wire to the tip of the wire feeding tip, controls the height of the wire so that the wire length is within a predetermined range, brings the base material molten by the arc into contact with the wire, and melts the wire with the current supplied to the wire, By analyzing the aforementioned image, the tip of the TIG electrode, the tip of the wire, and the boundary line of the weld bead from the previous pass are recognized. The lateral position of the tip of the TIG electrode is controlled to be within ΔY = W / 3 (W: weld bead width) from the boundary line. The lateral position of the tip of the wire is controlled to be within ΔY from the tip of the TIG electrode. A welding apparatus characterized in that the lateral distance D1 from the boundary line to the tip of the TIG electrode and the lateral distance D2 from the tip of the TIG electrode to the tip of the wire satisfy |D1 - D2| ≥ d (d: wire diameter).

2. A welding apparatus that receives images from a camera of a wire, a wire feeding tip for feeding the wire, a base material, and a TIG electrode for generating an arc, analyzes the images to measure the wire length, which is the length from the tip of the wire to the tip of the wire feeding tip, controls the height of the wire so that the wire length is within a predetermined range, brings the base material molten by the arc into contact with the wire, and melts the wire with the current supplied to the wire, By analyzing the aforementioned image, the tip of the TIG electrode, the tip of the wire, and the boundary line of the weld bead from the previous pass are recognized. The lateral position of the tip of the TIG electrode is controlled to be within ΔY = W / 3 (W: weld bead width) from the boundary line. The lateral position of the tip of the wire is controlled to be within ΔY from the tip of the TIG electrode. A welding apparatus characterized in that the lateral position of the tip of the wire is at least the wire diameter d away from the boundary line.

3. A welding apparatus that receives images from a camera of a wire, a wire feeding tip for feeding the wire, a base material, and a TIG electrode for generating an arc, analyzes the images to measure the wire length, which is the length from the tip of the wire to the tip of the wire feeding tip, controls the height of the wire so that the wire length is within a predetermined range, brings the base material molten by the arc into contact with the wire, and melts the wire with the current supplied to the wire, Perform a first build-up weld on one corner of the groove. Perform a second build-up weld on the other corner of the groove. Perform a k-th (k: 3, 4, ..., N) overlay weld in a direction away from the other corner of the groove until the bead bottom width, which indicates the distance between the first overlay weld and the Nth (N: integer of 3 or more) overlay weld, is 2d to 0.8W (d: wire diameter, W: weld bead width). If the bead bottom width is 2d to 5d, the lateral position of the tip of the TIG electrode is set to the center of the bead bottom width, and the lateral position of the tip of the wire is set to the same position as the lateral position of the TIG electrode, and the N+1th buildup welding is performed. A welding apparatus characterized in that, when the bead bottom width is 5d to 0.8W, the lateral position of the tip of the wire is set at a distance of at least the wire diameter d from the boundary line of the first build-up weld on the TIG electrode side, and at least the wire diameter d from the boundary line of the Nth build-up weld on the TIG electrode side, and a build-up weld is performed at a distance of at least the wire diameter d.

4. A welding apparatus according to claim 1, A welding apparatus characterized by detecting characteristic points of the TIG electrode from the aforementioned image and estimating the position of the tip of the TIG electrode from the characteristic points.

5. Camera and, An image processing device receives images of the wire, the wire feeding tip that feeds the wire, the base material, and the TIG electrode that generates the arc from the camera, analyzes the images to measure the wire length, which is the length from the tip of the wire to the tip of the wire feeding tip, and recognizes the tip of the TIG electrode, the tip of the wire, and the boundary line of the weld bead of the previous pass. The device includes a control device that controls the height of the wire so that the wire length is within a predetermined range, brings the base material melted by the arc into contact with the wire, and melts the wire with an electric current supplied to the wire. The control device is The lateral position of the tip of the TIG electrode is controlled to be within ΔY = W / 3 (W: weld bead width) from the boundary line, and the lateral position of the tip of the wire is controlled to be within ΔY from the tip of the TIG electrode. A welding apparatus characterized in that the lateral distance D1 from the boundary line to the tip of the TIG electrode and the lateral distance D2 from the tip of the TIG electrode to the tip of the wire satisfy |D1 - D2| ≥ d (d: wire diameter).

6. The process involves receiving images from a camera of the wire, the wire feeding tip for feeding the wire, the base material, and the TIG electrode that generates the arc. The process of analyzing the aforementioned image to measure the wire length, which indicates the length from the tip of the wire to the tip of the wire feeding chip, The steps include controlling the height of the wire so that the wire length is within a predetermined range, bringing the base material melted by the arc into contact with the wire, and melting the wire with the current supplied to the wire, The process involves analyzing the aforementioned image to recognize the tip of the TIG electrode, the tip of the wire, and the boundary line of the weld bead from the previous pass. A step of controlling the lateral position of the tip of the TIG electrode to be within ΔY = W / 3 (W: weld bead width) from the boundary line, The welding apparatus is instructed to perform the following steps: control the lateral position of the tip of the wire to be within ΔY from the tip of the TIG electrode. A welding method characterized in that the lateral distance D1 from the boundary line to the tip of the TIG electrode and the lateral distance D2 from the tip of the TIG electrode to the tip of the wire satisfy |D1 - D2| ≥ d (d: wire diameter).

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