Horizontal automatic welding method and horizontal automatic welding device

Abstract

To provide a horizontal automatic welding method capable of automatically generating welding conditions that suppress sagging of molten metal in horizontal welding of a groove.SOLUTION: A horizontal automatic welding method in which welding conditions based on the shape of a groove 4 are automatically generated by using a computer that controls a horizontal automatic welding device, and horizontal welding of the groove 4 is automatically performed under the generated welding conditions, comprises: calculating the lamination number of welding layers required to fill a cross section of the groove 4 with deposited metal, from a preset plate thickness and reinforcement height Hw of welding target materials 5 and 6 and a reference layer depth; calculating a welding layer depth of each welding layer; calculating a cross-sectional area of each welding layer; calculating a reference cross-sectional area per one pass of each welding layer; generating the welding conditions by calculating the number of welding passes in each welding layer from the cross-sectional area and the reference cross-sectional area; and performing horizontal welding of the groove 4 under the generated welding conditions.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a method and an apparatus for automatic horizontal welding of grooves. [Background technology]

[0002] When welding the weld line of the material to be welded, for example, in the groove of a T-joint or a flat joint, the welding torch travels along the direction in which the weld line extends (the weld line direction). Typically, the welding torch also moves back and forth across the width of the groove (weaving or oscillating). By combining the welding torch's travel in the weld line direction with its reciprocating movement across the groove width, the groove is filled with deposited metal, resulting in groove welding.

[0003] To reduce the labor required for such welding and improve the quality, welding robots that automatically detect the groove and automatically drive the welding torch based on welding conditions pre-registered in a computer have been developed and are now in use. For example, Patent Documents 1 and 2 disclose automatic welding devices equipped with welding robots that can perform horizontal welding.

[0004] In order to weld the groove of a workpiece using an automatic welding device, it is necessary to set welding conditions in advance according to the shape of the groove. The welding conditions are set, for example, by an operator using the automatic welding device, or in addition to being set by the operator, they may also be automatically set from known information based on a program pre-stored in the automatic welding device. In order to reduce the burden on the operator when setting these welding conditions, it is preferable to be able to set the welding conditions automatically as much as possible.

[0005] As an automatic welding method for automatically generating such welding conditions, Patent Document 3 discloses an automatic welding method in which welding conditions for each welding pass are automatically generated based on the shape of the groove and each welding pass is automatically welded under the generated welding conditions. Specifically, the method describes a method in which the weld height is calculated for each layer of the welding pass in the cross section of the groove, the weld heights calculated for each layer are added up, and when the added value of the weld height is equal to or greater than a reference height set for the weld plate thickness, the number of layers of welding passes required to fill the cross section of the groove is determined, and the welding speed of the welding pass is corrected from a reference welding speed so that the position of the top part of the welding pass in the uppermost layer is at the position of the reference reinforcement height, and welding is performed at the determined welding speed. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2022-144916 [Patent Document 2] Japanese Patent Publication No. 2023-003846 [Patent Document 3] Patent Publication No. 2021-016881 Summary of the Invention [Problem to be solved by the invention]

[0007] When building up the deposited metal in the groove, multiple welding passes are performed in which a molten wire is fed into the groove and solidified to form one layer of deposited metal. The automatic welding method described in Patent Document 3 relates to a method of performing multiple such welding passes, and is a technology that is particularly useful when performing flat welding.

[0008] On the other hand, when performing horizontal welding, the molten metal tends to drip due to the influence of gravity from the time when the wire fed into the groove melts until it solidifies. Therefore, when performing multiple welding passes in horizontal welding to build up the deposited metal, it is desirable to set the welding conditions for each welding pass taking the dripping of molten metal into consideration. However, the automatic welding method described in Patent Document 3 does not take into account the influence of the dripping of molten metal during horizontal welding, so there is room for improvement in terms of ensuring weld quality.

[0009] The present invention has been made in consideration of the above circumstances, and aims to provide an automatic horizontal welding method and an automatic horizontal welding device that can automatically generate welding conditions that can suppress dripping of molten metal in horizontal groove welding. [Means for solving the problem]

[0010] One aspect of the present invention that solves the above-mentioned problems is a horizontal position automatic welding method that automatically generates welding conditions based on the shape of a groove using a computer that controls a horizontal position automatic welding device, and automatically performs horizontal welding of the groove using the generated welding conditions. When generating the welding conditions before starting the horizontal position welding, the computer calculates the number of weld layers required to fill the cross section of the groove with weld metal from the plate thickness, reinforcement height, and reference layer depth of the material to be welded that are preset. The computer calculates the weld layer depth of each weld layer from the plate thickness, reinforcement height, and number of layers. The computer calculates a layer cross-sectional area, which is the cross-sectional area of ​​each weld layer, from the groove shape and the weld layer depth. The computer calculates a reference cross-sectional area per pass of each weld layer from the preset reference welding conditions and the diameter of the wire to be fed to the groove. The computer calculates the number of welding passes for each weld layer from the layer cross-sectional area and the reference cross-sectional area to generate the welding conditions, and performs horizontal welding of the groove using the generated welding conditions.

[0011] Another aspect of the present invention is an automatic horizontal welding device that automatically generates welding conditions based on a groove shape and automatically performs horizontal welding of the groove under the generated welding conditions, the device comprising: a welding torch; a torch movement mechanism that moves the welding torch in each of the directions of a weld line extending along a weld line, a depth direction of the groove, and a width direction of the groove; and control means, wherein the control means, when generating welding conditions before starting the horizontal welding, determines a welding condition for filling a cross section of the groove with a deposited metal from a plate thickness, a reinforcement height, and a reference layer depth of a material to be welded that are preset. the number of weld layers required for welding the groove is calculated, the depth of each weld layer is calculated from the plate thickness, the excess reinforcement height, and the number of layers, the cross-sectional area of ​​each weld layer is calculated from the shape of the groove and the weld layer depth, a standard cross-sectional area per pass of each weld layer is calculated from preset standard welding conditions and the diameter of the wire fed to the groove, the number of welding passes for each weld layer is calculated from the layer cross-sectional area and the standard cross-sectional area, welding conditions are generated by the calculation, and control is executed to perform horizontal welding of the groove under the generated welding conditions. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide an automatic horizontal welding method and an automatic horizontal welding device that can automatically generate welding conditions that can suppress dripping of molten metal in horizontal groove welding. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram showing an example of a state in which a horizontal automatic welding device according to an embodiment of the present invention is used. FIG. [Figure 2] FIG. 2 is a perspective view illustrating a structure around a welding robot of a horizontal automatic welding device. [Figure 3] FIG. 3 is a view of the welding robot as seen from the direction of arrow V in FIG. 2. [Figure 4] FIG. 4 is a view of the welding robot shown in FIG. 3 as seen from below. [Figure 5] FIG. 4 is a side view of the welding robot shown in FIG. 3. [Figure 6] FIG. 1 is a perspective view showing an example of materials to be welded. [Figure 7] 10 is a flowchart showing an example of "condition generation" executed by the horizontal automatic welding device according to the present embodiment. [Figure 8] FIG. 10 is a diagram showing an example of a cross-sectional area of ​​each welding pass with respect to a groove cross section, which is set by the condition generation method according to the present embodiment. [Figure 9] 10 is a flowchart illustrating an example of control for correcting the number of welding passes. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configuration are designated by the same reference numerals, and redundant description will be omitted.

[0015] (automatic welding equipment) FIG. 1 is a diagram showing an example of a state in which a horizontal automatic welding device 1 according to this embodiment is in use. The Y direction shown in the diagram is the direction in which a weld line extends (hereinafter referred to as the "weld line direction"). The X direction is the depth direction of the groove and is also a horizontal direction perpendicular to the weld line direction. The Z direction is the width direction of the groove and is also a vertical direction. The X direction, Y direction, and Z direction are directions perpendicular to each other.

[0016] The automatic welding apparatus 1 shown in FIG. 1 (hereinafter simply referred to as "welding apparatus 1") is an apparatus for performing horizontal welding of a groove 4 of materials 5 and 6 to be welded that extend in the YZ plane. The materials 5 and 6 to be welded are, for example, steel plates. The welding apparatus 1 includes a welding robot 10 that holds a welding torch 70 and a control panel 2 for controlling the operation of the welding robot 10.

[0017] <Control panel> Control panel 2 is composed of computer 3 (including a control unit, a calculation unit, a memory unit, etc.), a display, input keys, operation switches, indicator lights, etc. (not shown). Computer 3 in control panel 2 responds to input operations by the worker using welding device 1, and performs electronic processing such as setting welding conditions, detecting open ends, detecting groove shapes, calculating welding conditions, correcting, storing and editing welding data, as well as automatic control of welding robot 10, a wire feeder (not shown), a welding power source (not shown), an electromagnetic switch (not shown), etc.

[0018] <Welding robot peripheral structure> Next, the peripheral structure of welding robot 10 will be described in more detail with reference to Figures 2 to 5. Figure 2 is a perspective view for explaining the peripheral structure of welding robot 10. Figure 3 is a view of welding robot 10 as seen from the direction of arrow V in Figure 2. Figure 4 is a view of welding robot 10 shown in Figure 3 as seen from below. Figure 5 is a view of welding robot 10 shown in Figure 3 as seen from the side. Note that direction T shown in the figures is the rotation direction in which welding torch 70 swings.

[0019] The welding robot 10 is mounted on a guide rail 9 arranged parallel to the groove 4 of the materials 5 and 6 to be welded. The guide rail 9 is supported by four suction devices 7 and fixed onto the materials 5 to be welded. The suction devices 7 are, for example, magnets, and are attracted to the materials 5 to be welded by magnetic force.

[0020] The bottom of welding robot 10 is made up of a traveling carriage (hereinafter referred to as Y traveling carriage 20) that moves along the Y direction (weld line direction). Y traveling carriage 20 has a pinion (not shown) that meshes with a rack (not shown) provided on guide rail 9, and guide rail 9 and Y traveling carriage 20 form a rack-and-pinion linear movement mechanism (Y drive mechanism). This Y drive mechanism allows welding robot 10 to move back and forth in the Y direction.

[0021] In addition to the Y drive mechanism, the welding device 1 is also provided with an X drive mechanism (not shown) that moves the welding robot 10 in the X direction (depth direction of the groove 4). Furthermore, a Z drive mechanism (not shown) is also provided that moves the torch drive bar 44 shown in FIG. 5 in the Z direction (width direction of the groove) to move the welding torch 70 in the Z direction. Known structures can be applied to the X drive mechanism and the Z drive mechanism. For example, the Z drive mechanism disclosed in the aforementioned Patent Document 3 can be applied to the X drive mechanism according to this embodiment, and the X drive mechanism disclosed in Patent Document 3 can be applied to the Z drive mechanism according to this embodiment.

[0022] Each of the various drive mechanisms, the X drive mechanism, the Y drive mechanism, and the Z drive mechanism, is provided with an electric motor (not shown), such as a stepping motor, as a drive source. Computer 3 in control panel 2 shown in Fig. 1 controls the operation of each electric motor by providing drive command pulses to the motor drivers that drive the electric motors, and determines the rotation amount (X movement amount, Y movement amount, Z movement amount) of each motor to determine the position coordinates of welding torch 70.

[0023] Welding robot 10 is equipped with a torch attitude adjustment mechanism 50 (FIG. 5) for adjusting the attitude of welding torch 70. A known structure, such as the torch adjustment mechanism disclosed in the aforementioned Patent Document 3, can be applied to torch attitude adjustment mechanism 50. This torch attitude adjustment mechanism 50 can set welding torch 70 to a forward tilted attitude 70wf or a backward tilted attitude 70wr, as shown by the two-dot chain lines in FIG. 5, or any tilted attitude therebetween.

[0024] The welding robot 10 further includes a T-axis drive mechanism 60 that electrically rotates the welding torch 70. The T-axis drive mechanism 60 includes a motor case 61 and a bearing case 62, which are mounted on a plate 57. A T-axis 63, rotatably supported by a bearing in the bearing case 62, is connected to the output shaft of an electric motor (not shown) with a speed reducer inside the motor case 61. A torch holder 64 is connected to the T-axis 63, and the welding torch 70 is held by the torch holder 64. The forward rotation of the electric motor inside the motor case 61 places the welding torch 70 in a right-tilted position 70Tr, as shown by the two-dot chain line in FIG. 4, and the reverse rotation places the welding torch 70Tl in a left-tilted position 70Tl. The electric motor is, for example, a stepping motor. The computer 3 in the control panel 2 shown in FIG. 1 sends drive command pulses to a motor driver that drives the electric motor to control its operation and determine the amount of rotation (T-axis rotation amount) and the tilt of the swing rotation.

[0025] Welding apparatus 1 according to this embodiment is configured as described above. In this welding apparatus 1, welding torch 70 can be moved in the X, Y, and Z directions by the operation of various drive mechanisms, etc., and can also be rotated around the X direction and around the Y direction. In other words, welding apparatus 1 has a torch movement mechanism that moves welding torch 70 in each of the X, Y, and Z directions, and a torch rotation mechanism that rotates welding torch 70 around the X and Y directions.

[0026] (automatic welding method) Next, a description will be given of a horizontal automatic welding method using the above-described welding apparatus 1. In this embodiment, the description will focus on a method for automatically generating welding conditions for each pass when performing horizontal welding in a groove with multiple welding passes. However, before starting the automatic generation of welding conditions with the welding apparatus 1, a method for specifying the groove shape will first be described.

[0027] <Specifying groove shape> As an example of a method for specifying the groove shape, a fully automatic method for measuring the groove shape using the welding device 1 will be described. Fig. 6 is a perspective view showing an example of materials to be welded 5, 6. Note that a flat plate 80 in contact with the back side of the materials to be welded 5, 6 is a backing metal.

[0028] First, based on a control signal from computer 3 in control panel 2, an "origin adjustment" is performed to determine the X, Y, and Z positions of the tip of the welding wire fed to welding torch 70.

[0029] Next, welding robot 10 starts traveling in the Y-direction and measuring the traveling distance, and the first groove point Cs1, which is one end of the groove line, is detected. Specifically, by controlling the drive of T-axis drive mechanism 60, welding torch 70 is set to an inclined position pointing toward one end of groove 4 on the welding start side, and Y-traveling carriage 20 is driven to travel in the Y-direction. Contact between the tip of the welding wire and a face plate (not shown) at one end of groove 4 on the welding start side is detected, thereby detecting the first groove point Cs1. Thereafter, the tip of the welding wire is swung in a predetermined trajectory along the cross section of groove 4, and the groove shape of groove 4 at first groove point Cs1, such as the gap, groove angle, and plate thickness, is measured.

[0030] Next, Y-axis backward travel and travel distance measurement are started, and a second groove point Cs2, which is the end of the groove line opposite to the first groove point Cs1, is detected. Specifically, by controlling the drive of the T-axis drive mechanism 60, the welding torch 70 is set to an inclined position pointing toward one end of the groove 4 on the welding end side, and the Y-axis travel carriage 20 is driven to travel in the Y-axis backward direction. The second groove point Cs2 is detected by detecting contact between the tip of the welding wire and a face plate (not shown) at one end of the groove 4 on the welding end side. Thereafter, the tip of the welding wire is swung in a predetermined trajectory along the cross section of the groove 4, and the groove shape of the groove 4 at the second groove point Cs2, such as the gap, groove angle, and plate thickness, is measured.

[0031] The groove shape specification described above is performed fully automatically under the control of the computer 3 in the control panel 2, but for example, the position of the first groove point Cs1 and the position of the second groove point Cs2 may be stored in the computer 3 in the control panel 2 by an operator inputting coordinate information into the control panel 2. In this case, the welding device 1 does not perform the operation of specifying the position of the first groove point Cs1 and the position of the second groove point Cs2, but automatically measures the shape of the groove 4 at the input position of the first groove point Cs1 and the input position of the second groove point Cs2.

[0032] Further, for example, in addition to the position information of the first groove point Cs1 and the second groove point Cs2, an operator may input information on the groove shape, such as the gap, groove angle, and plate thickness of the groove 4, into the control panel 2 and store it in the computer 3 in the control panel 2. In this case, the welding device 1 does not perform an operation to identify the groove shape, but starts the "condition generation" control flow described later based on the input groove shape information. In other words, the method of identifying the groove shape required to start the "condition generation" control flow described later is not particularly limited, and the above-mentioned method or a known method can be applied.

[0033] <Condition generation> FIG. 7 is a flowchart showing an example of "condition generation" executed by the welding device 1 according to this embodiment.

[0034] First, as shown in step s1 in FIG. 7, the computer 3 in the control panel 2 calculates the cross-sectional area of ​​the first groove point Cs1 from the shape of the groove 4 at the first groove point Cs1. Similarly, the computer 3 calculates the cross-sectional area of ​​the second groove point Cs2 from the shape of the groove 4 at the second groove point Cs2. Next, the cross-sectional area of ​​the groove midpoint Csm, located in the middle of the groove line, is calculated based on the cross-sectional areas of the first groove point Cs1 and the second groove point Cs2. The cross-sectional area of ​​the groove midpoint Csm is, for example, the average of the cross-sectional areas of the first groove point Cs1 and the second groove point Cs2. This average is calculated and considered to be the cross-sectional area of ​​the groove midpoint Csm between the first groove point Cs1 and the second groove point Cs2. Note that the groove midpoint Csm is not necessarily located at half the distance from the first groove point Cs1 to the second groove point Cs2.

[0035] Next, as shown in step s2 in Fig. 7, the "number of weld layers" and "depth of each weld layer" required to fill the cross section of the groove midpoint Csn with weld metal are calculated. Specifically, the number of weld layers is calculated from the plate thickness, reinforcement height, and reference layer depth of the materials 5 and 6 to be welded, which are preset in the computer 3 in the control panel 2. The depth of each weld layer is then calculated from the calculated number of layers, the plate thickness, and reinforcement height of the materials 5 and 6 to be welded.

[0036] The "reference layer depth" is the length in the groove depth direction (X direction) per weld layer at which molten metal is less likely to drip during horizontal welding, and is set as appropriate by a person skilled in the art through horizontal welding experiments, etc. Note that the reference layer depth is a guideline depth at which molten metal dripping can be suppressed, and does not necessarily mean that dripping will occur when the actual weld layer depth exceeds the reference layer depth.

[0037] The number of weld layers and the depth of each weld layer are calculated, for example, as follows: Table 1 shows a calculation example when the reinforcement height Hw is set to 2 mm and the reference layer depth Dref is set to 4 mm.

[0038] [Table 1]

[0039] First, (plate thickness t + reinforcement height Hs) / reference layer depth Dref is calculated. The value calculated here, rounded down to the nearest integer, is the number of weld layers. For example, when the plate thickness t is 20 mm, the calculated value of (plate thickness t + reinforcement height Hs) / reference layer depth Dref is 5.5, and the number "5" obtained by rounding down this value to the nearest integer is the number of weld layers. In other words, when the plate thickness t is 20 mm, the condition for forming five weld layers in the groove 4 is set.

[0040] An example of a groove cross section in which five such weld layers are formed is shown in Figure 8. In this example, there are five weld layers consisting of a first layer A, a second layer B, a third layer C, a fourth layer D, and a fifth layer E. The numbers added within each of the weld layers A to E in Figure 8 indicate the number of welding passes within each layer. The method for determining the number of welding passes will be described later.

[0041] Next, using the number of weld layers calculated using the method described above, (plate thickness t + reinforcement height Hs) / number of layers is calculated. The value calculated here becomes the weld layer depth of each weld layer. As shown in Table 1 above, when the plate thickness t is 20 mm, the weld depth Ld of each weld layer (layers 1 to 5) is set to 4.4 mm.

[0042] Next, as shown in step s3 in Fig. 7, the "layer cross-sectional area" which is the cross-sectional area of ​​each welded layer is calculated. Specifically, the layer cross-sectional area is calculated for each welded layer from the shape of the groove 4 and the welded layer depth calculated in step s2, for example, using the following formula. Sn = (Gn × Ld + (Ld × tanθ) × Ld) / 2 Sn: Cross-sectional area of ​​the weld layer (mm 2 ), Gn: groove width of weld layer (mm), Ld: depth of weld layer (mm), θ: groove angle (°)

[0043] Next, as shown in step s4 in Fig. 7, the "reference cross-sectional area" per pass of each welding layer is calculated. Specifically, the reference cross-sectional area is calculated for each welding layer from the "reference welding conditions" preset in the computer 3 in the control panel 2 and the diameter of the wire fed into the groove 4.

[0044] The "reference welding conditions" are conditions including welding current, welding voltage, wire feed rate, welding speed, wire deposition efficiency, etc., and are set appropriately by a person skilled in the art through horizontal welding experiments, etc. The multiple welding layers are divided into the first layer, second layer, intermediate layer, and final layer, and the above-mentioned reference welding conditions are set for each of the first layer, second layer, intermediate layer, and final layer.

[0045] The "final layer" is the last welded layer formed among multiple welded layers, and is the welded layer closest to the surface of the materials 5 and 6 to be welded. In the example shown in FIG. 8, the fifth layer E is the final layer. The "intermediate layer" is the welded layer located between the second layer and the final layer. In the example shown in FIG. 8, the third layer C and the fourth layer D are welded layers belonging to the intermediate layer. Note that when the number of welded layers is four, the intermediate layer is composed of one layer, and when the number of welded layers is three, there is no intermediate layer.

[0046] The above-mentioned "reference cross-sectional area" per pass of each welded layer is calculated, for example, by the following formula. Sp=(Wf×(Wd / 2) 2 ×π×K) / Wmin Wf: Wire feed speed (m / min), Wd: Wire diameter (mm), K: Welding efficiency (%), Wmin: Lower limit of standard welding speed range (mm / min) The "reference welding speed range" is a range of welding speeds set as reference welding conditions.

[0047] Next, as shown in step s5 in Fig. 7, the number of welding passes for each welding layer is calculated. More specifically, the number of welding passes for each welding layer is calculated from the layer cross-sectional area of ​​each welding layer that has already been calculated and the reference cross-sectional area per pass. Specifically, (layer cross-sectional area Sn / reference cross-sectional area Sp) is calculated, and the calculated value is rounded down to the nearest integer to obtain the number of welding passes.

[0048] For example, the cross-sectional area Sn of the first layer A shown in FIG. 2 The reference cross-sectional area Sp in the first layer A is 29.0 mm 2 In this case, the calculated value of (layer cross-sectional area Sn / reference cross-sectional area Sp) is 1.33. The value calculated here is rounded down to the nearest whole number, which is "1", and this is the number of welding passes in the first layer A. For example, if the layer cross-sectional area Sn in the second layer B is 52.8 mm 2 The reference cross-sectional area Sp in the second layer B is 19.2 mm 2In this case, the calculated value of (layer cross-sectional area Sn / reference cross-sectional area Sp) is 2.74, and the number "2", which is obtained by rounding down the decimal point, is the number of welding passes in the second layer B. The numbers of welding passes in the third layer C to the fifth layer E are calculated in a similar manner. In addition, the calculated number of welding passes for each welding layer is used to calculate (layer cross-sectional area Sn / number of welding passes), thereby calculating the cross-sectional area of ​​each welding pass.

[0049] The above method determines the number of welding passes for each welding layer and the cross-sectional area of ​​each welding pass within the welding layer. Table 1 above includes examples in which the welding layer depth Ld calculated from the number of layers is greater than the reference layer depth set as the depth at which sagging is unlikely to occur. However, by setting the number of welding passes as described above, the cross-sectional area of ​​each welding layer can be appropriately subdivided. This makes it possible to suppress sagging of molten metal during welding with each welding pass.

[0050] When calculating the number of welding passes for each welding layer belonging to the intermediate layer (the third layer C and the fourth layer D in the example of FIG. 8), it is preferable to calculate ((layer cross-sectional area Sn - reference cross-sectional area Sp) / reference cross-sectional area Sp), round down the calculated value to the nearest integer, and then add "1" to set the number of welding passes as this. This makes it possible to prevent poor penetration that may occur during the final welding pass for each welding layer belonging to the intermediate layer.

[0051] Next, the cross-sectional area of ​​each welding pass is calculated as shown in step s6 in Fig. 7. Specifically, the cross-sectional area of ​​each welding pass is calculated from the already calculated layer cross-sectional area and the number of welding passes using, for example, the following formula. Spn=Sn / number of welding passes Spn: Cross-sectional area of ​​the weld path (mm 2 ), Sn: cross-sectional area of ​​the weld layer (mm 2 )

[0052] Next, the welding speed for each welding pass is calculated as shown in step s7 in Fig. 7. The welding speed is calculated from preset reference welding conditions, the diameter of the wire supplied to the groove, and the cross-sectional area of ​​the welding pass using, for example, the following formula. Ws = (Wf × (Wd / 2) 2 ×π×K) / Spn Ws: welding speed of welding pass (mm / min), Wf: wire feed speed (m / min), Wd: wire diameter (mm), K: deposition efficiency (%), Spn: cross-sectional area of ​​welding pass (mm 2 )

[0053] Next, as shown in step s8 in FIG. 7, the ratio of the welding speed at the first groove point Cs1 to the second groove point Cs2 is determined. Specifically, by comparing the cross-sectional areas of the first groove point Cs1 and the second groove point Cs2, the ratio of the welding speed at the first groove point Cs1 to the welding speed at the second groove point Cs2 relative to the welding speed at the groove midpoint Csm is determined. Then, based on the determined ratio, the welding speed for each welding pass at the first groove point Cs1 and the welding speed for each welding pass at the second groove point Cs2 are calculated. Next, the section from the first groove point Cs1 to the second groove point Cs2 along the groove line is divided into five regions Sa to Se, as shown in FIG. 6, for example. Then, the welding speed at the first groove point Cs1 and the welding speed at the second groove point Cs2 calculated based on the above ratio are used to determine the welding speed for each region by linear interpolation. For example, the welding speed at the first groove point Cs1 is set as the welding speed for the first region Sa, and the welding speed at the second groove point Cs2 is set as the welding speed for the last region Se, and the welding speed from the start point of the second region Sb to the end point of the fourth region Sd is determined by linear interpolation.

[0054] Next, as shown in step s9 in FIG. 7, oscillation conditions (e.g., oscillation speed) for each of regions Sa to Se are calculated according to the determined welding speed. Specifically, the oscillation speed is calculated based on conditions such as the oscillation width and oscillation end point stop time for each welding layer that are preset by the operator, and welding torch 70 is oscillated during welding according to the calculated oscillation speed. Note that welding torch 70 oscillates as needed, and welding device 1 has a configuration that allows oscillation to be switched ON / OFF. For example, if the oscillation setting is set to OFF before the start of the condition generation flow shown in FIG. 7, oscillation condition generation step s9 is skipped. Alternatively, for example, the oscillation may be set to ON only when welding the first layer of multiple welding layers, and OFF when welding the other welding layers.

[0055] Through the above steps s1 to s9, the "condition generation" is completed by the computer 3 that controls the welding device 1. After that, automatic horizontal welding of the groove is started based on the generated welding conditions.

[0056] In the horizontal position automatic welding method according to this embodiment, the number of weld layers, the number of welding passes, etc. are calculated starting from a reference layer depth that is preset as a depth at which molten metal dripping is unlikely to occur. This makes it possible to automatically generate welding conditions that take molten metal dripping during horizontal position welding into consideration.

[0057] In this embodiment, an example has been described in which steps s2 to s7 are performed based on the cross-sectional area of ​​the groove midpoint Csm, but the target cross section for performing these steps s2 to s7 is not limited to the cross section of the groove midpoint Csm, and may be a cross section at another position within the groove line. In other words, even if steps s2 to s7 are performed on a groove cross section at an arbitrary position within the groove line, it is possible to automatically generate welding conditions such as the number of weld layers stacked and the number of welding passes for that cross section.

[0058] Furthermore, when calculating the welding speed for each welding pass in the above-mentioned step s7, it is preferable to correct the number of welding passes as needed in accordance with the flowchart shown in Fig. 9. This will be specifically described below.

[0059] <Correction of the number of welding passes> First, as shown in step s71 in FIG. 9, it is determined whether the calculated welding speed is equal to or greater than the lower limit of the reference welding speed range. The reference welding speed range is the range of welding speeds set as the reference welding conditions, as described above. If the welding speed is below the lower limit of the reference welding speed range in step s71, the process proceeds to step s72. Examples of cases in which the welding speed is below the lower limit of the reference welding speed range are shown in Table 2 below.

[0060] [Table 2]

[0061] In the example of Table 2, the standard welding speed range for the intermediate layer is set to 400 to 550 (mm / min), but the calculated welding speed for the first and second passes of the fourth layer is 386 (mm / min), which is below the lower limit of the standard welding speed range for the intermediate layer, 400 (mm / min).The lower limit of the standard welding speed range for the intermediate layer is set as a speed at which sagging is unlikely to occur during horizontal welding of the intermediate layer, so it is preferable to modify the welding speed to improve the effect of suppressing sagging.

[0062] Therefore, in the flow shown in FIG. 9, if there is a welding pass whose welding speed is below the lower limit of the reference welding speed range, the number of welding passes in the welding layer including that welding pass is increased by one pass in step s72. In the example of Table 2, the number of welding passes in the fourth layer is increased from three passes to four passes. Next, in step s73, the cross-sectional area of ​​each welding pass is recalculated in a manner similar to step s7 in FIG. 7. Using the cross-sectional area of ​​each welding pass calculated here, the welding speed for each welding pass is recalculated in step s74 in a manner similar to step s7 in FIG. 7. Then, the process returns to step s71, and it is again determined whether the recalculated welding speed is equal to or greater than the lower limit of the reference welding speed range.

[0063] In step s71, if the welding speed is equal to or greater than the lower limit of the reference welding speed range, the process proceeds to step s75. In step s75, it is determined whether the welding speed is equal to or less than the upper limit of the reference welding speed range. In step s75, if the welding speed exceeds the upper limit of the reference welding speed range, the process proceeds to step s76. Examples of such cases where the welding speed exceeds the upper limit of the reference welding speed range are shown in Table 3 below.

[0064] [Table 3]

[0065] In the example of Table 3, the calculated welding speed for the first to third passes of the fourth layer is 579 (mm / min), which exceeds the upper limit of the standard welding speed range for the middle layer, 550 (mm / min). When there is a welding pass whose welding speed exceeds the upper limit of the standard welding speed range, the number of welding passes for the welding layer including that welding pass is reduced by one pass in step s76. In the example of Table 3, the number of welding passes for the fourth layer is reduced from four passes to three passes. Next, in step s77, the cross-sectional area of ​​each welding pass is recalculated in a manner similar to step s6 of FIG. 7. Using the calculated cross-sectional area of ​​each welding pass, the welding speed for each welding pass is recalculated in step s78 in a manner similar to step s7 of FIG. 7. Then, the process returns to step s75, where it is again determined whether the recalculated welding speed is equal to or less than the upper limit of the standard welding speed range.

[0066] By carrying out the control of steps s71 to s78 described above, the number of welding passes can be corrected until the welding speed for each welding pass falls within the reference welding speed range, and more appropriate welding conditions can be automatically generated.

[0067] <Anti-sagging bead> When performing horizontal welding of the groove 4, as shown in Fig. 8, a sag prevention bead 90 may be formed at a corner on the surface side of the material to be welded 6 located below the groove 4. The sag prevention bead 90 is a weld bead that extends in the weld line direction (Y direction).

[0068] The final layer (the fifth layer E in the example of FIG. 8) is a weld layer that includes the weld height Hw. Therefore, if the weld depth of each of the weld layers A to D becomes excessively larger than the design value when the first layer A to the fourth layer D are actually welded, the fifth layer E may not be fully contained within the groove 4, and sagging may easily occur during welding of the fifth layer E.

[0069] In such a case, if the anti-sag bead 90 is formed in advance, the deposited metal of the first pass of the fifth layer E will be placed on the anti-sag bead 90, thereby suppressing the molten metal from dripping from the groove 4. Furthermore, by forming the anti-sag bead 90, the ceramic tab that has conventionally been used as a part for preventing sag is no longer necessary, thereby reducing the cost of the part.

[0070] The timing of forming the sag prevention bead 90 is not particularly limited as long as it is formed before the start of welding of the final layer. In the example of Fig. 8, the sag prevention bead 90 may be formed before the start of the first welding pass of the first layer A, or may be formed after the end of the third welding pass of the fourth layer D but before the start of the first welding pass of the fifth layer E.

[0071] Furthermore, when generating welding conditions, for example, when the size of the excess weld height Hw set in the computer 3 in the control panel 2 is equal to or greater than a predetermined threshold, welding conditions may be generated to form a sag prevention bead 90 before starting welding of the final layer.

[0072] While the present invention has been described above by way of example, it is understood that the present invention is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications and alterations within the scope of the technical ideas set forth in the claims, and that such modifications and alterations are also within the technical scope of the present invention.

[0073] For example, the components of the above-described embodiments can be combined in any manner, and such combinations will naturally provide the functions and advantages of each of the components in the combination, as well as other functions and advantages that will be apparent to those skilled in the art from the description herein.

[0074] Furthermore, the effects described herein are merely descriptive or exemplary and are not limiting. In other words, the technology according to the present disclosure may achieve other effects that are apparent to those skilled in the art from the description of this specification, in addition to or in place of the above-described effects.

[0075] Note that the following configuration examples also fall within the technical scope of the present disclosure. (1) A horizontal automatic welding method in which welding conditions based on the shape of a groove are automatically generated using a computer that controls a horizontal automatic welding device, and horizontal welding of the groove is automatically performed under the generated welding conditions, The computer, when generating welding conditions before starting the horizontal welding, Calculating the number of weld layers required to fill the cross section of the groove with weld metal from the plate thickness, weld height, and reference layer depth of the material to be welded that are set in advance; Calculating the welding layer depth of each welding layer from the plate thickness, the reinforcement height, and the number of layers; A layer cross-sectional area, which is a cross-sectional area of ​​each weld layer, is calculated from the shape of the groove and the weld layer depth; Calculating a reference cross-sectional area per pass of each weld layer from preset reference welding conditions and the diameter of the wire fed to the groove; generating welding conditions by calculating the number of welding passes in each welding layer from the layer cross-sectional area and the reference cross-sectional area; A horizontal automatic welding method, characterized in that horizontal welding of the groove is performed under the generated welding conditions. (2) The computer: The horizontal automatic welding method according to (1), characterized in that when calculating the number of welding passes for the intermediate layer when the multiple welding layers are divided into a first layer, a second layer, an intermediate layer, and a final layer, the number of welding passes for the intermediate layer is calculated from the value obtained by subtracting the reference cross-sectional area from the layer cross-sectional area and the reference cross-sectional area. (3) The computer: Calculating a welding speed for each welding pass from the reference welding conditions and the diameter of the wire fed to the groove; The horizontal automatic welding method according to (1) or (2), characterized in that control is performed to correct the number of welding passes so that the welding speed falls within a preset reference welding speed range. (4) A horizontal automatic welding method according to any one of (1) to (3), characterized in that, before starting welding of the final layer of the plurality of weld layers, a bead extending along the weld line direction is formed at a corner on the surface side of the workpiece to be welded, which is located below the groove. (5) An automatic horizontal welding device that automatically generates welding conditions based on the shape of a groove and automatically performs horizontal welding of the groove under the generated welding conditions, A welding torch, a torch moving mechanism that moves the welding torch in each of a welding line direction in which a welding line extends, a depth direction of the groove, and a width direction of the groove; a control means; The control means, when generating welding conditions before starting the horizontal welding, Calculating the number of weld layers required to fill the cross section of the groove with weld metal from the plate thickness, weld height, and reference layer depth of the material to be welded that are set in advance; Calculating the welding layer depth of each welding layer from the plate thickness, the reinforcement height, and the number of layers; A layer cross-sectional area, which is a cross-sectional area of ​​each weld layer, is calculated from the shape of the groove and the weld layer depth; Calculating a reference cross-sectional area per pass of each weld layer from preset reference welding conditions and the diameter of the wire fed to the groove; generating welding conditions by calculating the number of welding passes in each welding layer from the layer cross-sectional area and the reference cross-sectional area; A horizontal automatic welding device that executes control to perform horizontal welding of the groove under the generated welding conditions. (6) The horizontal automatic welding device according to (5), characterized in that when calculating the number of welding passes for the intermediate layer when the plurality of welding layers are divided into a first layer, a second layer, an intermediate layer, and a final layer, the control means executes control to calculate the number of welding passes for the intermediate layer from the value obtained by subtracting the reference cross-sectional area from the layer cross-sectional area and the reference cross-sectional area. (7) The control means Calculating a welding speed for each welding pass from the reference welding conditions and the diameter of the wire fed to the groove; The horizontal automatic welding device according to (5) or (6), characterized in that control is performed to correct the number of welding passes so that the welding speed falls within a preset reference welding speed range. (8) The horizontal automatic welding device according to any one of (5) to (7), characterized in that the control means executes control to form a bead extending along the weld line direction at a corner on the surface side of the workpiece to be welded, which is located below the groove, before starting welding of the final layer of the plurality of weld layers. [Industrial Applicability]

[0076] The present invention can be applied to a method for automatic horizontal welding of grooves. [Explanation of symbols]

[0077] 1: Automatic welding equipment 2: Control panel 3: Computer 4: Bevel 5, 6: Welding target material 7: Suction tool 9: Guide rail 10: Welding robot 20:Y traveling cart 50: Torch attitude adjustment mechanism 60:T-axis drive mechanism 61: Motor case 62: Bearing case 63 :T-axis 64: Torch holder 70: Torch 70wf: forward tilted posture 70wr: backward tilting position 70Tr: Right leaning posture 70Tl: Left leaning posture 80: Backing 90: Anti-sagging bead A: 1st layer B: 2nd layer C: 3rd layer D: 4th layer E: 5th layer Cs1: Bevel 1st point Cs2: 2nd bevel point Csm: Bevel midpoint Hw: Reinforcement height Sa~Se: area

Claims

1. A horizontal automatic welding method that automatically generates welding conditions based on the shape of a groove using a computer that controls a horizontal automatic welding device, and automatically performs horizontal welding of the groove under the generated welding conditions, The computer, when generating welding conditions before starting the horizontal welding, Calculating the number of weld layers required to fill the cross section of the groove with weld metal from the plate thickness, weld height, and reference layer depth of the material to be welded that are set in advance; Calculating the welding layer depth of each welding layer from the plate thickness, the reinforcement height, and the number of layers; A layer cross-sectional area, which is a cross-sectional area of ​​each weld layer, is calculated from the shape of the groove and the weld layer depth; Calculating a reference cross-sectional area per pass of each weld layer from preset reference welding conditions and the diameter of the wire fed to the groove; generating welding conditions by calculating the number of welding passes in each welding layer from the layer cross-sectional area and the reference cross-sectional area; A horizontal automatic welding method, characterized in that horizontal welding of the groove is performed under the generated welding conditions.

2. The computer 2. The horizontal automatic welding method according to claim 1, wherein when the number of welding passes for the intermediate layer is calculated when the plurality of welding layers are divided into a first layer, a second layer, an intermediate layer, and a final layer, the number of welding passes for the intermediate layer is calculated from the value obtained by subtracting the reference cross-sectional area from the layer cross-sectional area and the reference cross-sectional area.

3. The computer Calculating a welding speed for each welding pass from the reference welding conditions and the diameter of the wire fed to the groove; 3. The horizontal automatic welding method according to claim 1, wherein control is performed to correct the number of welding passes so that the welding speed falls within a preset reference welding speed range.

4. 3. The horizontal automatic welding method according to claim 1, wherein a bead extending along the weld line direction is formed at a corner on the surface side of the workpiece to be welded that is located below the groove before starting welding of a final layer of the plurality of weld layers.

5. An automatic horizontal welding device that automatically generates welding conditions based on the shape of a groove and automatically performs horizontal welding of the groove under the generated welding conditions, A welding torch, a torch moving mechanism that moves the welding torch in each of a welding line direction in which a welding line extends, a depth direction of the groove, and a width direction of the groove; a control means; The control means, when generating welding conditions before starting the horizontal welding, Calculating the number of weld layers required to fill the cross section of the groove with weld metal from the plate thickness, weld height, and reference layer depth of the material to be welded that are set in advance; Calculating the welding layer depth of each welding layer from the plate thickness, the reinforcement height, and the number of layers; A layer cross-sectional area, which is a cross-sectional area of ​​each weld layer, is calculated from the shape of the groove and the weld layer depth; Calculating a reference cross-sectional area per pass of each weld layer from preset reference welding conditions and the diameter of the wire fed to the groove; generating welding conditions by calculating the number of welding passes in each welding layer from the layer cross-sectional area and the reference cross-sectional area; A horizontal automatic welding device that executes control to perform horizontal welding of the groove under the generated welding conditions.

6. 6. The horizontal automatic welding device according to claim 5, wherein when calculating the number of welding passes for the intermediate layer when the plurality of welding layers are divided into a first layer, a second layer, an intermediate layer, and a final layer, the control means executes control to calculate the number of welding passes for the intermediate layer from the value obtained by subtracting the reference cross-sectional area from the layer cross-sectional area and the reference cross-sectional area.

7. The control means Calculating a welding speed for each welding pass from the reference welding conditions and the diameter of the wire fed to the groove; 7. The horizontal automatic welding device according to claim 5, wherein control is performed to correct the number of welding passes so that the welding speed falls within a preset reference welding speed range.

8. 7. The horizontal automatic welding device according to claim 5, wherein the control means executes control to form a bead extending along the weld line direction at a corner on the surface side of the workpiece to be welded that is located below the groove before starting welding of a final layer of the plurality of weld layers.

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