Control method, control device, welding system, control program, and welding method

Abstract

To provide a method of control that can acquire excellent weld quality even when using a GMAW method having high welding efficiency for welding when a groove is provided in a material to be welded, the material to be welded and a welding wire have different compositions, and a welding wire including 5% or more Ni is used.SOLUTION: A method of controlling a welding robot or a control device relating to GMAW when a groove is provided in a material to be welded, the material to be welded and a welding wire have different compositions, and the welding wire includes 5% or more Ni includes: a construction information setting step of setting construction information including at least one of a board thickness, a groove depth, and an estimated weld metal height and at least one of the gap and a groove width in a center position of a preliminarily calculated layer height; and a welding condition setting correction step of calculating a weaving width on the basis of the construction information and setting or correcting a welding condition including at least the weaving width before welding or during welding.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to a control method, a control device, a welding system, a control program, and a welding method. [Background technology]

[0002] In recent years, liquefied natural gas (hereinafter referred to as "LNG") has attracted attention as a clean fuel, and its production and use have been increasing. Due to increasing demand, tanks for storing LNG (hereinafter referred to as "LNG tanks") are required to have larger capacities and shorter construction periods. Naturally, however, large-capacity LNG tanks require a significant amount of welding. Furthermore, aboveground LNG tanks generally have a double structure consisting of a metal inner vessel and an outer vessel. The welding of this inner vessel is typically performed using 9% Ni steel plates as the welded material (hereinafter referred to as the "base material," "workpiece," or simply "steel plate") and Ni-based alloy welding materials (hereinafter referred to as "welding wire"), which maintain the same toughness and strength as the base material in the as-welded state. While 9% Ni steel is commonly used for inner vessel materials, there has been a recent trend toward reducing the Ni content, and steel plates containing Ni in the range of 5 to 12% are being considered for use as inner vessel materials.

[0003] Welding the inner tank is extremely difficult and requires high welding skills due to the various physical properties that vary depending on the composition of the steel plate and welding material. For this reason, welding of the inner tank, which requires excellent welding quality, requires skilled welders to carefully weld by hand, which reduces welding work efficiency. As mentioned above, the larger the capacity, the greater the welding volume, and the lower the welding work efficiency, so the longer the construction period for manufacturing LNG tanks. Therefore, in the past, there has been a demand for improvements in welding work efficiency as a means to shorten construction times while achieving larger capacity.

[0004] Automated welding is an effective means for improving the efficiency of welding work, and automated welding is being considered and applied to the welding of the inner tanks of LNG tanks. For example, Patent Document 1 discloses a method for constructing the side plates of the inner tank of a flat cylindrical tank, which can be constructed efficiently in a short construction period by appropriately using mobile scaffolding equipment and automatic control devices, and discloses that the vertical welding process of the inner tank uses an automatic control device for gas-shielded arc welding using a flux-cored wire, and the horizontal welding process uses an automatic control device for submerged arc welding. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-3461 Summary of the Invention [Problem to be solved by the invention]

[0006] Conventionally, automatic welding using GTAW (Gas Tungsten Arc Welding) has been used in addition to the automatic welding using GMAW (Gas Metal Arc Welding) and SAW (Submerged Arc Welding) described in Patent Document 1. However, as described above, welding of the inner vessel is extremely difficult due to the difference in composition between the steel plate and the welding material, and requires advanced welding technology.

[0007] For example, the melting point of Ni-based alloys, which are used as welding materials, is more than 100°C lower than that of 9% Ni steel. As a result, there is a risk of deterioration in welding quality, such as dripping of the molten metal, poor bead appearance, or poor groove penetration and fusion. Therefore, when converting various welding methods to automated welding, consideration must be given to reducing welding work efficiency, such as slowing down the welding speed, in order to ensure high-quality welding.

[0008] Furthermore, unlike manual welding and semi-automatic welding, automatic welding does not allow for optimization of welding conditions, such as adjusting the rod handling (hereinafter also referred to as "weaving") or the welding speed according to the welding situation. Therefore, it is extremely difficult to select welding conditions, which may result in a deterioration in welding quality due to improper welding conditions. Patent Document 1 does not disclose any mention of achieving both excellent welding quality and improved welding efficiency, and does not particularly consider welding quality. Furthermore, while GMAW is a welding method with superior welding efficiency regardless of the welding position compared to SAW and GTAW, ensuring excellent welding quality while maintaining excellent welding efficiency requires advanced welding skills. Therefore, in reality, welding sites currently rely on semi-automatic welding, particularly when welding in difficult positions such as the vertical position.

[0009] As described above, the difficulty in automating GMAW, which has high welding efficiency, is due to the difficulty of welding due to the difference in physical properties between the steel sheet and the welding material. Therefore, the fundamental problem occurs when the physical properties of the steel sheet and the welding material differ, i.e., when the composition of the steel sheet and the welding material differ. Furthermore, the higher the Ni content of welding wire, the lower the melting point tends to be. This problem becomes more pronounced when welding wire containing 5% or more Ni is used. Therefore, it is desirable to enable automatic welding that can ensure excellent weld quality even when the composition of the steel sheet and the welding material differs and the welding wire contains 5% or more Ni. In addition to the welding of LNG tanks mentioned above, other applications include welding of liquefied ethylene gas tanks (hereinafter also referred to as "LEG tanks") and liquefied CO2 tanks, and in both applications, welding wire containing 5% or more Ni may be used. Furthermore, when the base metals are different, such as when the steel sheet is Fe-based and the welding material is Ni-based, the problem becomes more difficult due to the significant difference in the physical properties of the steel sheet and the welding material. Furthermore, the combination of a steel plate containing 5 to 12% Ni and a welding material made of Ni steel or Ni-based alloy containing Ni at least as much as the steel plate, which is envisaged for LEG tanks and LNG tanks, is an even more difficult challenge, but naturally, this is a challenge that the present invention can solve in any application.

[0010] Therefore, in consideration of the above-mentioned problems, the present invention aims to provide a control method, a control device, a welding system, a control program, and a welding method that can obtain excellent welding quality even when using a GMAW method with high deposition efficiency in welding when a groove is provided in a workpiece, the workpiece and the welding wire have different compositions, and a welding wire containing 5% or more Ni is used. [Means for solving the problem]

[0011] Therefore, the above object of the present invention is achieved by the following configuration [1]. [1] A control method for a welding robot or a control device for GMAW in which a groove is provided in a workpiece, the workpiece and the welding wire have different compositions, and the welding wire contains 5% or more Ni, A construction information setting process for setting construction information including at least one of a plate thickness, a groove depth, and an estimated weld metal height, and at least one of a gap and a groove width at a center position of a previously calculated layer height; a welding condition setting and correction process for calculating a weaving width based on the construction information before or during welding, and setting or correcting welding conditions including at least the weaving width; A method for controlling a welding robot or a control device, comprising:

[0012] The above object of the present invention can be achieved by the following configuration [2]. [2] A control device for controlling a welding robot in GMAW in which a groove is provided in a workpiece, the workpiece and the welding wire have different compositions, and the welding wire contains 5% or more Ni, A construction information setting function for setting construction information including at least one of a plate thickness, a groove depth, and an estimated weld metal height, and at least one of a gap and a groove width at a center position of a previously calculated layer height; a welding condition setting and correction function that calculates a weaving width based on the construction information before or during welding and sets or corrects welding conditions including at least the weaving width; A control device comprising:

[0013] The above object of the present invention can be achieved by the following configuration [3]. [3] A welding system for controlling a welding robot in GMAW in which a groove is provided in a workpiece, the workpiece and the welding wire have different compositions, and the welding wire contains 5% or more Ni, The welding machine includes at least a control device and a welding power source, The control device A construction information setting function for setting construction information including at least one of a plate thickness, a groove depth, and an estimated weld metal height, and at least one of a gap and a groove width at a center position of a previously calculated layer height; a welding condition setting and correction function that calculates a weaving width based on the construction information before or during welding and sets or corrects welding conditions including at least the weaving width; A welding system comprising:

[0014] The above object of the present invention can be achieved by the following configuration [4]. [4] A control program for controlling a welding robot in GMAW in which a groove is provided in a workpiece, the workpiece and the welding wire have different compositions, and the welding wire contains 5% or more Ni, A construction information setting function for setting construction information including at least one of a plate thickness, a groove depth, and an estimated weld metal height, and at least one of a gap and a groove width at a center position of a previously calculated layer height; a welding condition setting and correction function that calculates a weaving width based on the construction information before or during welding and sets or corrects welding conditions including at least the weaving width; A control program comprising:

[0015] The above object of the present invention can be achieved by the following configuration [5]. [5] A welding method for GMAW in which a groove is provided in a workpiece, the workpiece and the welding wire have different compositions, and the welding wire contains 5% or more Ni, A construction information setting process for setting construction information including at least one of a plate thickness, a groove depth, and an estimated weld metal height, and at least one of a gap and a groove width at a center position of a previously calculated layer height; a welding condition setting and correction process for calculating a weaving width based on the construction information before or during welding, and setting or correcting welding conditions including at least the weaving width, In the welding condition setting correction step, When the value of the gap or the value of the groove width at the center position of the previously calculated layer height is smaller than the wire diameter of the welding wire, a weaving width is calculated based on a preset value, a welding method, characterized in that, when the gap value or the previously calculated groove width value at the center position of the layer height is larger than a wire diameter of the welding wire, a weaving width is calculated so that W / G, which is a ratio of W meaning the weaving width to G meaning the gap value or the previously calculated groove width value at the center position of the layer height, is not more than a first value and not less than a second value. However, the first value and the second value are values ​​based on the groove depth, the estimated weld metal height - the reinforcement height, or the plate thickness. [Effects of the Invention]

[0016] According to the present disclosure, in welding in which a groove is provided in a workpiece, the workpiece and the welding wire have different compositions, and a welding wire containing 5% or more Ni is used, even when the GMAW method, which has high deposition efficiency, is used, automatic welding using the GMAW method that can obtain excellent weld quality and welding work efficiency becomes possible. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a welding system according to an embodiment of the present disclosure. [Figure 2]FIG. 2 is a schematic diagram illustrating a configuration of a portable welding robot according to an embodiment of the present disclosure. [Figure 3] FIG. 3 is a perspective view showing the configuration of a portable welding robot according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a conceptual diagram illustrating an approximate linear movement mechanism according to an embodiment of the present disclosure. [Figure 5] FIG. 5 is a perspective view of vertical welding using a portable welding robot according to an embodiment of the present disclosure. [Figure 6] FIG. 6 is a schematic diagram illustrating touch sensing according to an embodiment of the present disclosure. [Figure 7] FIG. 7 is a conceptual diagram illustrating some of the setting conditions according to the embodiment of the present disclosure. [Figure 8] FIG. 8 is a flowchart illustrating a welding control method according to an embodiment of the present disclosure. [Figure 9] FIG. 9 is a perspective view illustrating an example of the arrangement position of the visual sensor according to the embodiment of the present disclosure. [Figure 10] FIG. 10 is a diagram illustrating an image captured by a visual sensor according to an embodiment of the present disclosure. [Figure 11] FIG. 11 is a schematic diagram illustrating an example configuration of a data processing device according to an embodiment of the present disclosure. [Figure 12] FIG. 12 is an explanatory diagram conceptually illustrating a process for generating a trained model according to an embodiment of the present disclosure. [Figure 13] FIG. 13 is a diagram illustrating an example of a screen used for a teaching operation according to an embodiment of the present disclosure. [Figure 14] FIG. 14 is an explanatory diagram showing a specific example of a welding image obtained by welding and an example of welding information in the welding image, according to an embodiment of the present disclosure. [Figure 15] FIG. 15 illustrates a first example of welding according to an embodiment of the present disclosure. [Figure 16] FIG. 16 is a plot diagram corresponding to an embodiment of the present disclosure. [Figure 17]FIG. 17 illustrates a second example of welding according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, a welding system according to one embodiment of the present invention will be described with reference to the drawings. Note that this embodiment is an example of a case in which a portable welding robot is used. The welding system of the present invention is not limited to the configuration of this embodiment.

[0019] Note that unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters or redundant descriptions of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. Note that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0020] For example, the term "unit" or "device" in the embodiments is not limited to a physical configuration mechanically realized by hardware, but also includes a configuration whose functions are realized by software such as a program. Furthermore, the functions of one configuration may be realized by two or more physical configurations, or the functions of two or more configurations may be realized by, for example, one physical configuration.

[0021] <Welding system configuration> 1 is a schematic diagram showing the configuration of a welding system according to an embodiment of the present disclosure. As shown in FIG. 1, the welding system 50 includes a portable welding robot 100, a feeder 300, a welding power source 400, a shielding gas supply source 500, and a control device 600.

[0022] [Control device] Control device 600, which corresponds to the control device of the present disclosure, is connected to portable welding robot 100 via robot control cable 610 and to welding power source 400 via power supply control cable 620. Control device 600 has a data storage unit 601 that stores teaching data that predefines the portable welding robot 100's movement pattern, welding start position, welding end position, construction conditions, welding conditions, etc., and sends commands to portable welding robot 100 and welding power source 400 based on this teaching data to control the movement and welding conditions of portable welding robot 100. Control device 600 may have a memory, and data storage unit 601 may be included in the memory. Note that the memory corresponds to a storage device.

[0023] The control device 600 also has a groove shape information calculation unit 602 that calculates groove shape information from detection data obtained by sensing, which will be described later, and a welding condition acquisition unit 603 that corrects and acquires the welding conditions of the teaching data based on the groove shape information. The groove shape information calculation unit 602 and the welding condition acquisition unit 603 form a control unit 604. The control unit 604 may include a processor.

[0024] The control device 600 has a control program that controls the portable welding robot 100. The control program is stored in a storage device such as a memory of the control device 600. A processor included in the control device 600 reads and executes the control program, thereby controlling the portable welding robot 100. The control program has various functions related to the control of the portable welding robot 100.

[0025] Although not shown in the drawings due to its general configuration, the control device 600 is formed by integrating a controller for teaching and manual operation of the portable welding robot 100, and a controller with other control functions. However, the control device 600 is not limited to this, and may be divided into multiple controllers based on their roles, such as a controller for teaching and a controller with other control functions, or the portable welding robot 100 may include the control device 600. In this embodiment, signals are transmitted using the robot control cable 610 and the power supply control cable 620, but this is not limiting and signals may be transmitted wirelessly. From the perspective of usability at a welding site, it is preferable to divide the control device into two controllers: a controller for teaching and manual operation of the portable welding robot 100, and a controller with other control functions.

[0026] [Welding power source] In response to a command from the control device 600, the welding power source 400 supplies power to the welding wire 211, which is a consumable electrode, and the workpiece Wo, thereby generating an arc between the welding wire 211 and the workpiece Wo. The power from the welding power source 400 is sent to the wire feeder 300 via a power cable 410, and then sent from the wire feeder 300 to the welding torch 200 via a conduit tube 420. As shown in FIG. 2, which is a schematic diagram showing the configuration of a portable welding robot according to an embodiment of the present disclosure, the power from the welding power source 400 is supplied to the welding wire 211 via a contact tip at the tip of the welding torch 200. The current used during welding may be direct current or alternating current, and its waveform is not particularly important. Therefore, the current may be a pulsed current such as a square wave or a triangular wave.

[0027] Furthermore, welding power source 400 has, for example, power cable 410 connected to welding torch 200 as a positive electrode, and power cable 430 connected to workpiece Wo as a negative electrode. Note that this is the case when welding is performed with reverse polarity; when welding with positive polarity, the power cable of the positive electrode is connected to workpiece Wo, and the power cable of the negative electrode is connected to welding torch 200.

[0028] [Shielding gas supply source] Shielding gas supply source 500 is composed of a container filled with shielding gas, a valve, and other auxiliary components. Shielding gas is sent from shielding gas supply source 500 to feeder 300 via gas tube 510. The shielding gas sent to feeder 300 is sent to welding torch 200 via conduit tube 420. The shielding gas sent to welding torch 200 flows through welding torch 200, is guided to nozzle 210, and is ejected from the tip side of welding torch 200. The shielding gas used in this embodiment may be, for example, argon (Ar), carbon dioxide (CO2), or a mixture thereof, but it is preferable to use 100% CO2 gas for welding.

[0029] [Feeding device] The feeder 300 pays out the welding wire 211 and feeds it to the welding torch 200. The welding wire 211 fed by the feeder 300 is not particularly limited and is selected depending on the properties of the workpiece Wo, the welding form, and the like. For example, a solid wire or a flux-cored wire is used, but from the viewpoint of welding efficiency, a flux-cored wire is preferable. The welding wire will be described in detail later, but in this embodiment, it is preferable to use a high-Ni material such as an Inconel or Hastelloy material, and more preferably, a Hastelloy material. Furthermore, the diameter of the welding wire is not particularly limited, but in this embodiment, the upper limit and lower limit of the wire diameter are preferably 1.6 mm and 0.9 mm, respectively.

[0030] Conduit tube 420 according to this embodiment has a conductive path formed on the outer skin side of the tube to function as a power cable, a protective tube for protecting welding wire 211 disposed inside the tube, and a flow path for shielding gas formed therein. However, conduit tube 420 is not limited to this, and for example, a power supply cable and a hose for supplying shielding gas bundled together around a protective tube for feeding welding wire 211 to welding torch 200 can also be used. Also, for example, the tubes for feeding welding wire 211 and shielding gas and the power cable can be installed separately.

[0031] [Portable welding robot] 2 and 3, the portable welding robot 100 includes a guide rail 120, a robot body 110 that is installed on the guide rail 120 and moves along the guide rail 120, and a torch connection unit 130 that is placed on the robot body 110. Note that FIG. 3 is a perspective view showing the configuration of a portable welding robot according to an embodiment of the present disclosure. The robot body 110 is mainly composed of a main body 112 that is installed on the guide rail 120, a fixed arm 114 that is attached to the main body 112, and a welding torch rotation drive unit 116 that is attached to the fixed arm 114 so as to be rotatable in the direction of arrow R1.

[0032] 4 is a conceptual diagram showing an approximate linear movement mechanism according to an embodiment of the present disclosure. As shown in FIG. 4, the torch connection unit 130 is attached to the welding torch rotation drive unit 116 via a sliding table 169 and a crank 170. The torch connection unit 130 includes a torch clamp 132 and a torch clamp 134 that secure the welding torch 200. In addition, the main body 112 is provided with a cable clamp 150 on the side opposite to the side on which the welding torch 200 is attached, the cable clamp 150 supporting the conduit tube 420 that connects the feeding device 300 and the welding torch 200.

[0033] In addition, in this embodiment, a voltage is applied between the workpiece Wo and the welding wire 211, and a touch sensor is used as the detection means for sensing the surface of the groove 10, etc., by utilizing a voltage drop phenomenon that occurs when the welding wire 211 comes into contact with the workpiece Wo. The detection means is not limited to the touch sensor of this embodiment, and an image sensor, a laser sensor, etc., or a combination of these detection means may also be used, but it is preferable to use the touch sensor of this embodiment in view of the simplicity of the device configuration.

[0034] The main body 112 of the robot main body 110 is equipped with an X-axis movement mechanism 181 that moves the robot main body 110 along the guide rail 120 in the X-axis direction, which is perpendicular to the plane of Fig. 2 and corresponds to the direction of the weld line, as indicated by the arrow X in Fig. 2. The main body 112 also has a Y-axis movement mechanism 182 that moves the fixed arm 114 relative to the main body 112 via the slide support part 113 in the Y-axis direction, which is perpendicular to the X-axis and Z-axis directions and corresponds to the width direction of the groove 10. The main body 112 also has a Z-axis movement mechanism 183 that moves the robot main body 110 in the depth direction of the groove 10, which is perpendicular to the X-axis direction.

[0035] Furthermore, as shown in FIG. 4, sliding table 169 to which torch connecting part 130 is attached, crank 170, and welding torch rotation drive part 116 constitute an approximate linear movement mechanism 180 that moves the tip of welding wire 211 along an approximate linear line described below.

[0036] Specifically, a crank 170 is fixed to a rotating shaft 168 of a motor (not shown) that is fixed to welding torch rotation drive unit 116, and the tip of crank 170 is connected to one end of sliding table 169 by connecting pin 171. Sliding table 169 has a long groove 169a in the middle, and fixing pin 172 fixed to welding torch rotation drive unit 116 is slidably fitted into long groove 169a.

[0037] As a result, when crank 170 is rotated about rotation shaft 168 by a motor (not shown), sliding table 169 rotates about fixed pin 172 as a fulcrum and moves along long groove 169a while being guided by fitted fixed pin 172. That is, torch connection part 130 to which welding torch 200 is attached drives the tip of welding wire 211 along an approximate straight line indicated by imaginary line IL in FIG. 4 with respect to the X-axis direction while tilting welding torch 200 by rotating crank 170 as indicated by arrow R2 in FIGS. 3 and 4 . Note that, in this embodiment, the mechanisms for movement in the X-axis direction include X-axis movement mechanism 181 and approximate linear movement mechanism 180 described above. In the following description, when these mechanisms are distinguished, movement in the X-axis direction by X-axis movement mechanism 181 will be referred to as the "XA-axis direction," and movement in the X-axis direction by approximate linear movement mechanism 180 will be referred to as the "XB-axis direction." When neither mechanism is particularly important, the description will simply refer to the "X-axis direction."

[0038] Furthermore, welding torch rotation drive unit 116 is rotatably attached to fixed arm unit 114 as shown by arrow R1 in FIG. 2, and can be adjusted to an optimum angle and fixed.

[0039] As described above, robot body 110 can drive welding torch 200, which is its tip, with four degrees of freedom in three directions, namely, the X-axis direction, the Y-axis direction, and the Z-axis direction, by approximate linear movement mechanism 180, X-axis movement mechanism 181, Y-axis movement mechanism 182, and Z-axis movement mechanism 183. However, robot body 110 is not limited to this, and may be capable of being driven with any number of degrees of freedom depending on the application.

[0040] With the above configuration, the tip of welding wire 211 of welding torch 200 attached to torch connecting part 130 can be directed in any direction. That is, robot body 110 can be driven in the X-axis direction on guide rail 120. Welding torch 200 can also be driven in the Y-axis direction, which is the width direction of groove 10, or in the Z-axis direction, which is the depth direction of groove 10. Furthermore, by driving welding torch 200 with crank 170, it is possible to tilt welding torch 200 depending on the construction situation, for example, by providing a forward angle or a backward angle, which will be described later.

[0041] An attachment member 140 such as a magnet or an adsorption pad is provided below the guide rail 120, and the guide rail 120 is configured to be easily attached to and detached from the workpiece Wo by the attachment member 140. When setting the portable welding robot 100 on the workpiece Wo, the operator can easily set the portable welding robot 100 on the workpiece Wo by grasping the handles 160 on both sides of the portable welding robot 100.

[0042] <Weaving control method> Next, a weaving control method using the control device 600 provided in the welding system 50 according to this embodiment will be described in detail. Note that in this embodiment, vertical welding, which is the most difficult type of welding work for the inner vessel of an LNG tank, will be used as an example for the following description. Also, FIG. 5 shows a perspective view of vertical welding using the portable welding robot 100 according to this embodiment of the present disclosure. In this embodiment, welding is performed from bottom to top as viewed from the surface of FIG. 5, i.e., the direction of the arrow on the X-axis shown in FIG. 5 is the welding direction, and weaving is performed so as to intersect with the welding direction.

[0043] When welding the groove 10, welding information for welding is set or acquired before welding begins. The welding information may be set manually, for example. The welding information may be acquired by sensing, for example. The welding information here refers to a collective term for a group of information related to welding, including at least construction information and welding condition information. In addition to construction information and welding condition information, examples of welding information include environmental information including information on items such as temperature and humidity, and welding phenomenon information including information on items such as spatter and fume amount.

[0044] Examples of items constituting the construction information include gap, plate thickness, groove depth, estimated weld metal height, welding material, shielding gas type, base material, weld length, number of layers, number of passes, and buildup height for each layer. The term "estimated weld metal height" refers to the sum of the groove depth and any estimated buildup height. Examples of items constituting the welding condition information include welding current, arc voltage, welding speed, shielding gas flow rate, weaving width, weaving cycle, weaving end stop time, weaving reference line position, and weaving pattern. Examples of weaving patterns include diagonal weaving. Hereinafter, weaving conditions such as weaving width, weaving cycle, weaving end stop time, weaving reference line position, and weaving pattern will be collectively referred to as "weaving conditions." Weaving width is also referred to as "weaving amplitude" or simply "amplitude."

[0045] Furthermore, examples of a simplified process for acquiring welding process information and welding condition information before welding include the following (A) to (C).

[0046] (A) In the control device 600, a welding mode is determined according to items of the construction information, such as the type of welding wire, the type of shielding gas, and the welding position, and a condition acquisition and correction database (hereinafter also referred to as a "condition acquisition and correction DB") is determined for each welding mode. The condition acquisition and correction DB may be stored, for example, in the memory of the control device 600, or may be stored in a storage device provided in another device that can communicate with the control device 600.

[0047] (B) The robot body 110 is driven based on an operation signal from the control device 600, and automatic sensing of the groove shape is started using the touch sensor.

[0048] (C) Calculate groove shape information by the above automatic sensing, and calculate layer design information based on the groove shape information. Based on at least the groove shape information, layer design information, and the above-mentioned DB for condition acquisition and correction, obtain construction conditions, welding conditions, etc., or correct pre-set welding conditions, etc.

[0049] Next, in this embodiment, the process from acquiring the above-mentioned construction information and welding condition information to acquiring or correcting various conditions will be described in detail below.

[0050] [Sensing step before welding] The sensing step before the start of welding is performed by touch-sensing the groove shape, plate thickness, start and end points, etc. using the touch sensor described above. FIG. 6 is a schematic diagram showing touch sensing according to an embodiment of the present disclosure. The tip of the welding wire 211 is moved to each of positions A0 to A14 in FIG. 6, and the shape of the workpiece is sensed. By identifying the position when the tip of the welding wire 211 touches the workpiece, for example, A1, A3, A5, A6, etc., the groove shape, plate thickness, start and end points, etc. described above can be identified.

[0051] After the sensing step, a groove shape information calculation step is performed in which groove shape information is calculated from the detection data of the groove cross-sectional shape at each groove shape detection position obtained in the sensing step. Here, groove shape information includes, for example, the groove angle of the groove shape, plate thickness, groove depth, estimated weld metal height, gap, and the distance between the workpiece ends. After this groove shape information calculation step, a step is performed in which the calculated data is input to the data storage unit 601. In this embodiment, in the groove shape information calculation step, at least one of the plate thickness, groove depth, and estimated weld metal height and the gap are calculated as groove shape information and input to the data storage unit 601. Note that, in the groove shape information calculation step, if the gap is smaller than the wire diameter of the welding wire, the gap amount may be calculated as 0. Furthermore, a layer design information calculation step is performed in which layer design information is calculated based on the calculated groove shape information. Here, layer design information includes, for example, the number of layers, the number of passes, and the build height for each layer. After this lamination design calculation step, the calculated data is input to the data holding unit 601 .

[0052] Next, based on the groove shape information and layer design information data input to the data storage unit 601 and the condition acquisition and correction DB, the welding conditions in the teaching program data are set or corrected. In this embodiment, for example, the welding current, arc voltage, welding speed, and weaving conditions are set or corrected. The arc start position may also be determined. Note that "setting or correcting" means setting a setting value if it has not yet been set, or correcting a setting value if it has already been set.

[0053] FIG. 7 is a conceptual diagram illustrating some of the setting conditions according to an embodiment of the present disclosure. The example in FIG. 7 shows a case where three layers and four passes are calculated based on the layer design information. The layer-pass unit shown in FIG. 7 is, for example, "1-1" for the first layer and first pass, "3-3" for the third layer and third pass, and "3-4" for the third layer and fourth pass. Therefore, in FIG. 7, the groove is welded so that passes are formed in the following order: 1-1 (first layer and first pass), 2-2 (second layer and second pass), 3-3 (third layer and third pass), and 3-4 (third layer and fourth pass). In multi-layer welding, welding the first layer (referred to as 1-1 in FIG. 7), which is the welding portion where the composition differs between the workpiece and the welding wire, is the most difficult. Therefore, the present invention is most effective in welding the first layer. In this embodiment, the weaving conditions are determined based on at least one set value of the plate thickness, groove depth, or estimated weld metal height, and a predetermined amplitude DB, and the weaving amplitude is acquired and corrected or set as a welding condition in the teaching program data. That is, in FIG. 7, the weaving widths W1 to W4 are corrected or set. The amplitude DB may be stored in the memory of the control device 600, for example, or may be stored in a storage device provided in another device that can communicate with the control device 600.

[0054] The amplitude DB may include table data that associates a correction value for the weaving amplitude (hereinafter also referred to as a "weaving width correction value") with at least one set value of the plate thickness, the groove depth, or the estimated weld metal height as a threshold value, for example.

[0055] A more specific example will be given in which the estimated weld metal height is used as the threshold to be included in the table data. The thresholds for the estimated weld metal height are set to 16 mm, 22 mm, and 25 mm. A weaving width correction value is determined for each range defined by these three thresholds and stored in advance as an amplitude DB. That is, by referring to the amplitude DB, a first weaving width correction value can be obtained when the estimated weld metal height is 16 mm or less. A second weaving width correction value can be obtained when the estimated weld metal height is between 16 mm and 22 mm or less. A third weaving width correction value can be obtained when the estimated weld metal height is between 22 mm and 25 mm or less. A fourth weaving width correction value can be obtained when the estimated weld metal height is greater than 25 mm. For example, if the estimated weld metal height is calculated to be 18 mm in the sensing step described above, the weaving width correction value is the second weaving correction value because the estimated weld metal height falls within the range of more than 16 mm to 22 mm or less based on the amplitude DB.

[0056] Note that an amplitude DB may be created in advance to define a weaving width correction value for each threshold value, and the weaving width correction value to be set may be derived from the amount of change in the weaving width correction value between the threshold values. For example, an amplitude DB may be used in which the estimated weld metal height is used as the threshold value, and the weaving width correction value is set to 5 mm when the estimated weld metal height is 16 mm, and the weaving width correction value is set to 11 mm when the estimated weld metal height is 22 mm. In this case, if the estimated weld metal height is calculated to be 18 mm in the sensing step described above, the weaving width correction value is derived to be 7 mm based on the amplitude DB. For example, 7 mm may be derived based on the following formula: Weaving width correction value = 5 + (11-5) x (18-16) / (22-16)

[0057] In this embodiment, the weaving width correction value indicates an increase or decrease on one side based on the gap width or the groove width at the center position of the layer height calculated in advance. In other words, when the gap width is used as the reference, the basic formula for calculating the value of the calculated weaving amplitude (mm) is the set gap width (mm) + (weaving width correction value (mm) × 2). For example, when the gap width is 5 mm and the weaving width correction value is 2 mm, the weaving amplitude is calculated to be 9 mm. Note that when the gap is 0, the above basic formula may be used, and it may be set so that weaving is not performed or weaving is performed at a predetermined fixed value only when the gap is 0. The layer height is the build-up height for one layer calculated as the layer design information. For example, if the target position is the first layer, the groove width at the center position of the calculated build-up height of the first layer is used as the reference. Also, if the target layer is multi-pass, the calculated value can be divided by the number of passes. For example, if the weaving amplitude is calculated as 9 mm and the target layer is calculated as two passes in the layer design information, the true weaving amplitude for each pass is calculated as 4.5 mm.

[0058] The weaving width correction value may also be set as a coefficient for the gap. In this case, the set gap width (mm) x weaving width correction value (coefficient) may be used as the basic formula. For example, if the gap width is 5 mm and the weaving width correction value has a coefficient of 1.2, the weaving amplitude is calculated to be 6 mm.

[0059] Note that a different correction value or correction formula C may be added to, subtracted from, multiplied by, or divided by the above basic formula. For example, in the case of addition, weaving width = basic formula + C. In the case of multiplication, weaving width = basic formula × C.

[0060] As described above, welding of the inner vessel of an LNG tank involves welding a 5-12% Ni steel plate and a high-Ni welding material. Due to the differences in the physical properties of the steel plate and the welding material, welding is extremely difficult and requires advanced welding techniques. In the present invention, it has been discovered that by determining the weaving amplitude based on the plate thickness, groove depth, or estimated weld metal height, excellent welding quality can be ensured with GMAW of a 5-12% Ni steel plate and a high-Ni welding material, even with automatic welding. Below, we describe the specific control ranges that allow for better welding efficiency and weld quality to be achieved with automatic welding.

[0061] Except when the value of the groove width at the center of the gap or layer height is 0, it is preferable to set the weaving width so that the ratio of the set gap value (G) or groove width value at the center of the layer height (G) to the weaving width (W) falls within the numerical range between the first and second values ​​described below, depending on at least one of the plate thickness, groove depth, and estimated weld metal height. Note that the first value is greater than the second value. By setting the weaving width in this way, the amount of molten metal forming the weld pool can be suppressed, the appropriate amount of molten metal can be maintained, and bead dripping, leakage from the backing material, and insufficient fusion at the weaving end can be suppressed.

[0062] The ratio (W / G) of either the gap (G) or the groove width (G) at the center of the layer height to the weaving width (W) in the above example refers to the value obtained by dividing the weaving width by the groove width at the center of the gap or layer height. If the plate thickness is thick, heat is more likely to escape, which may result in a poor shape if left as is. Therefore, even if the groove width at the center of the gap or layer height is the same, it is preferable to widen the weaving when the plate thickness is thicker, and it is preferable to set the gap to weaving width ratio as large as possible within the range of the first value mentioned above.

[0063] In addition, information associating construction information including plate thickness, groove depth, or estimated weld metal height with multiple welding conditions may be stored in advance in a condition acquisition and correction DB or an amplitude DB, and welding conditions other than the weaving amplitude may be further set or corrected based on the set values ​​of plate thickness, groove depth, or estimated weld metal height and the DB.

[0064] A more preferred process of this embodiment will now be described with reference to Figure 8. Figure 8 is a flow chart illustrating a welding control method according to an embodiment of the present disclosure.

[0065] As a preparation before welding, in step S1, touch sensing is performed under the control of the control device 600 (sensing process). In the sensing process, at least the plate thickness, weld length, groove angle, root gap, and surface step are measured. Note that the groove depth, estimated weld metal height, etc. may also be measured.

[0066] In step S2, the control device 600 calculates values ​​of at least the plate thickness, weld length, groove angle, root gap, and surface step, and inputs them as setting values ​​of the control device 600 (groove shape information calculation step). Note that the groove depth, estimated weld metal height, etc. may also be input as setting values.

[0067] In step S3, at least the number of layers, the number of passes, and the build-up height of each layer are calculated from these set values ​​as lamination plan information, and input as set values ​​for the control device 600 (lamination design information calculation step). In this invention, the "construction information setting process" is defined as a general term for processes that have some kind of calculation means and input setting values, such as the groove shape information calculation process in step S2 and the laminate design information calculation process in step S3. In this embodiment, the construction information setting process includes at least two processes, the groove shape information calculation process and the laminate design information calculation process.

[0068] In step S4, the control device 600 determines the welding conditions including at least the weaving width based on the set values ​​and the information stored in various DBs, and sets or corrects the welding conditions (welding condition setting / correction process).

[0069] In step S5, a welding program is started under the control of control device 600. Then, in step S6, welding is started (arc on), and predetermined welding is performed until welding is completed (arc off) in step S7.

[0070] Next, in step S8, control device 600 determines whether the welding program is complete. That is, it determines whether all welding processes defined in the welding program are complete. If not complete, that is, if step S8 branches to NO, the process returns to step S6, and the operations of steps S6 and S7 are repeated again.

[0071] Note that "program completion" in step S8 means that welding has been completed at all positions from the welding start position to the welding end position previously determined in the welding program. In the case of multi-layer welding, "program completion" means that welding of all layers has been completed at each of the above positions. In this case, the operations of steps S6 and S7 are repeated until welding of all layers has been completed. Then, if it is determined in step S8 that the program has been completed, the welding work is terminated.

[0072] In addition to setting the weaving width, it is also preferable to set or correct the torch angle before or during welding. Welding materials containing 5% or more Ni tend to have a lower melting point and melt more easily than steel sheets with a lower Ni content than the welding material, resulting in a larger amount of molten metal forming the weld pool. If this amount of molten metal increases, the arc heat will not reach the steel sheet, potentially resulting in a lack of penetration. Even if the welding current is increased to achieve penetration, the amount of molten metal will increase, preventing the arc heat from reaching the steel sheet and potentially causing drooling. In such cases, the torch angle is typically angled upward to push up the molten metal to prevent drooling. However, in the present invention, it is preferable to set or control the torch angle downward, i.e., to a sweepback angle, before welding or during welding. This is because welding materials containing 5% or more Ni have a relatively low melting point and a fast solidification rate, and therefore, by prioritizing the arc reaching the steel sheet rather than focusing on pushing up the molten metal to prevent dripping, favorable effects can be achieved in terms of penetration performance. For example, the torch angle is preferably within a range of a sweepback angle of 0 to 20 degrees. In this embodiment, the torch angle is set to a sweepback angle of 10 degrees. In the vertical position of this embodiment, it is more preferable to set a desired torch angle to a sweepback angle before welding. In addition, in the vertical position, it is preferable to tilt the torch in the direction of the sweepback angle, but the direction in which the torch is tilted can be changed as appropriate depending on the welding position.

[0073] <Modification> In this embodiment, the welding conditions are set or corrected before welding. However, the portable welding robot 100 may be equipped with a visual sensor or laser sensor that captures the welding phenomenon during welding and appropriately corrects the welding conditions during welding. For example, a welding image including a molten pool captured by a visual sensor may be input, and the area and features of the molten pool may be calculated based on image processing, and conditions such as the welding current, arc voltage, welding speed, weaving conditions, and torch angle may be corrected based on the calculated data. Note that the setting or correction of the welding conditions during welding may be performed, for example, between steps S6 and S7 in FIG. 8.

[0074] Alternatively, a trained model may be prepared by acquiring multiple pieces of training data that associate welding image data obtained by a visual sensor or the like during welding with feature information obtained from welding phenomenon information such as the shape of the molten pool, the arc position, and spatter and fume conditions. The acquired training data may be used to input the welding image data and output the feature information. This trained model may be used to input welding image data obtained during welding as needed, and welding conditions during welding may be set or corrected based on the feature information output from the trained model. More preferably, at least one feature value among the features related to the wire position, the molten pool shape, and the arc position may be output, and at least one of the welding current, the arc voltage, the welding speed, and the torch angle may be corrected based on the feature value.

[0075] <Welding wire composition> Next, the welding material (welding wire) used in the present invention will be described. In the specification, "to" is used to mean that the numerical values ​​before and after it are included as the lower and upper limits. Furthermore, "(wire)" added immediately after an element refers to the total amount of the element in mass % relative to the total mass of the wire, and the element equivalent value of the compound related to that element, unless otherwise specified. For example, Mn (Wire) When "Mn" is displayed, it refers to the total Mn content of the entire wire and the Mn equivalent of compounds related to Mn. Note that Mn in the entire wire includes Mn contained in the hoop and Mn metal powder contained in the flux. Furthermore, "(metal)" added immediately after an element refers to the content in the deposited metal, and is expressed as a mass % of the total mass of the deposited metal.

[0076] In this embodiment, the welding material is used for welding the inner tank material of an LNG tank, i.e., a steel plate containing 5 to 12% Ni. The welding material may be a flux-cored wire or a solid wire, but from the viewpoint of deposition amount, a flux-cored wire is preferred. In the case of a solid wire, the composition range specified in JIS Z 3334:2011 is preferable. In the case of a flux-cored wire, the composition range of the welding wire is preferably the chemical composition range of the deposited metal specified in JIS Z 3335:2021 for nickel and nickel alloy arc welding flux-cored wire. Furthermore, depending on the application, elements other than those specified in JIS Z 3335:2021 may be further added to the flux-cored wire based on common general technical knowledge, which may adjust mechanical properties or improve welding workability.

[0077] Furthermore, the flux-cored wires specified in JIS Z 3335:2021 are either Inconel-based or Hastelloy-based, but it is more preferable to use Hastelloy-based wires because they can ensure high-temperature cracking resistance, high toughness even at extremely low temperatures, and it is even more preferable for the Hastelloy-based wires to have a chemical composition range for the welding wire that is the chemical composition range for the deposited metal specified in JIS Z 3335:2021 TNi1013 or JIS Z 3335:2021 TNi6275.

[0078] The chemical composition of the flux-cored wire that satisfies the most preferred chemical composition range of the deposited metal specified in JIS Z 3335:2021 TNi1013 or JIS Z 3335:2021 TNi6275 and that can be used in this embodiment will be described in more detail below, along with the reasons for the limitations. Note that the deposited metal is produced according to the procedure specified in JIS Z3184:2003, and the composition of the flux-cored wire is designed according to this procedure so that the chemical composition of the deposited metal satisfies the chemical composition specified in JIS Z 3335:2021 TNi1013 or JIS Z 3335:2021 TNi6275.

[0079] (C (Wire) :0.050% by mass or less) C is an element that affects the strength of the deposited metal or weld metal, and the higher the content, the higher the strength. It may be added to satisfy the strength range required for welding nickel and nickel alloys, but if added in excess, carbides are more likely to precipitate in the deposited metal or weld metal, which may reduce toughness relative to the target strength, resulting in an imbalance between strength and toughness. Therefore, the C content in the wire (Wire) is preferably 0.050% by mass or less, and more preferably 0.040% by mass or less. On the other hand, in order to adjust the strength, the C content is preferably 0.001% by mass or more. Sources of C in the wire include graphite and carbides added to the flux, and C contained in the hoop. However, from the viewpoint of suppressing carbides, the lower the C content, the better, so it is best not to add C to the flux as much as possible.

[0080] (Mn (Wire) :5.00% by mass or less) Mn is a gamma phase forming element and is effective in strengthening the matrix. It is contained to satisfy the mechanical performance required for welding nickel and nickel alloys. Adding too much Mn may increase the number of inclusions and reduce toughness. Therefore, the Mn content in the wire (Wire) On the other hand, in order to adjust the strength, the content of Mn is set to 5.00 mass % or less, and more preferably 1.80 mass % or less. (Wire) is preferably 0.01% by mass or more. The Mn source in the wire may be a metal powder of Mn added to the flux, a metal powder of an alloy of Mn, a compound of Mn, or Mn contained in the hoop. For example, Mn metal, Fe-Mn alloy, MnO2, and MnCO3 contained in the flux may be mentioned.

[0081] (Si (Wire) :3.0% by mass or less) Si is a component that increases the viscosity of the slag and is an effective component for obtaining a good bead shape, so it may be contained in the wire of this embodiment. However, if it is contained in excess, there is a risk that the slag removability will decrease. Therefore, in the wire of this embodiment, the Si content (Wire) is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.3% by mass or more, and is preferably 3.0% by mass or less, more preferably 1.5% by mass or less. Examples of Si sources in the wire include metal powder of Si, metal powder of Si alloys, Si compounds, and Si contained in the hoop, added to the flux. Examples include Si oxides such as silica sand, potassium feldspar, wollastonite, sodium silicate, and potassium silicate, as well as elemental Si and Si alloys such as Fe-Si that may be contained in the flux.

[0082] (P (Wire) :0.020 mass% or less) (S (Wire) :0.020 mass% or less) P and S are components contained as unavoidable impurities in the wire of this embodiment. (Wire) or S (Wire) If the content of P exceeds 0.02 mass %, low melting point compounds of these elements and Ni are generated in the grain boundaries, which reduces the hot cracking resistance. (Wire) and S (Wire) It is preferable to suppress each of them to 0.020 mass % or less.

[0083] (Cr (Wire) :20% by mass or less) Cr has the effect of improving the corrosion resistance and strength of the weld metal, but if the Cr content in the wire exceeds 20 mass %, the hot cracking resistance decreases. (Wire) In the wire of this embodiment, the content of Cr is 20 mass % or less. (Wire)is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more, and is preferably 20% by mass or less, more preferably 19% by mass or less, and even more preferably 18% by mass or less. The Cr source in the wire may be a Cr metal powder added to the flux, a Cr alloy metal powder, a Cr compound, or Cr contained in the hoop. When Cr is added as a flux, it is preferably added as a Cr metal powder or a Cr alloy metal powder, and examples thereof include simple Cr metal, an Fe-Cr alloy, and Cr2O3.

[0084] (Mo (Wire) :10~20% by mass) Mo has the effect of improving the corrosion resistance and strength of the weld metal, but if the content exceeds 20 mass %, the hot cracking resistance decreases. (Wire) In the wire of this embodiment, the content of Mo is 10 to 20 mass %. (Wire) is preferably 11% by mass or more, more preferably 12% by mass or more, and is preferably 19% by mass or less, more preferably 18% by mass or less. The Mo source in the wire may be Mo metal powder added to the flux, Mo alloy metal powder, Mo compound, or Mo contained in the hoop. When Mo is added as a flux, it is preferably added as Mo metal powder or Mo alloy metal powder, for example, metallic Mo and Fe-Mo alloy.

[0085] (Al (Wire) :3.00% by mass or less) Al is a strong deoxidizing element, and by causing an oxidation reaction in the weld metal, oxides (hereinafter also referred to as "slag") are formed on the molten pool, making it possible to weld in all positions, including difficult positions such as vertical welding and overhead welding. If added in excess, inclusions will increase, so the Al content (Wire) The content of Al is 3.00% by mass or less. It is more preferable that the content is 2.50% by mass or less, and further more preferable that the content is 1.70% by mass or less. (Wire)is preferably 0.10 mass% or more. The Al source in the wire may be Al metal powder, Al alloy metal powder, Al compound, or Al contained in the hoop, added to the flux. When Al is added as a flux, it is preferable to add Al metal powder, Al alloy metal powder, or Al2O3 in the form of Al2O3, since this can further reduce the amount of oxygen in the weld metal.

[0086] (Mg (Wire) :3.00% by mass or less) Like Al, Mg is a strong deoxidizing element, and by causing an oxidation reaction in the weld metal, oxides are formed on the molten pool, making it possible to weld in all positions, including difficult positions such as vertical welding and overhead welding. If added in excess, inclusions will increase, so the Mg content (Wire) The content of Mg is 3.00% by mass or less. It is more preferable that it is 1.50% by mass or less, and further more preferable that it is 1.00% by mass or less. (Wire) is preferably 0.30% by mass or more, and more preferably 0.50% by mass or more. Examples of Mg sources in the wire include Mg metal powder, Mg alloy metal powder, Mg compound, or Mg contained in the hoop, added to the flux. When Mg is added as flux, it is preferable to add Mg metal powder or Mg alloy metal powder, since this can further reduce the amount of oxygen in the weld metal.

[0087] (Ti (Wire) :5.00% by mass or less) Like Al, Ti is a strong deoxidizing element, and by causing an oxidation reaction in the weld metal, oxides are formed on the molten pool, making it possible to weld in all positions, including difficult positions such as vertical welding and overhead welding. If added in excess, inclusions increase, so the Ti content (Wire)The content of Ti is 5.00 mass% or less. The Ti source in the wire may be Ti metal powder, Ti alloy metal powder, Ti compound, or Ti contained in the hoop, added to the flux. When Ti is added as a flux, it is preferable to add it in the form of Ti metal powder, Ti alloy metal powder, or TiO2, since this can further reduce the amount of oxygen in the weld metal.

[0088] (Zr (Wire) :3.00% by mass or less) Like Al, Zr is a strong deoxidizing element, and by causing an oxidation reaction in the weld metal, oxides are formed on the molten pool, making it possible to improve burn-through resistance in all welding positions, including difficult positions such as vertical welding and overhead welding. If added in excess, inclusions increase, so the Zr content (Wire) The content of Zr in the wire is 3.00 mass % or less. The Zr source in the wire may be a Zr metal powder added to the flux, a Zr-related alloy metal powder, a Zr-related compound, or Zr contained in the hoop. When Zr is added in the flux, it is preferably added in the form of ZrO2, as this has the effect of improving the arc blowability and improving the arc stability even in a low welding current range.

[0089] (Ca (Wire) :3.00% by mass or less) Like Al, Ca is a strong deoxidizing element, and by causing an oxidation reaction in the weld metal, oxides are formed on the molten pool, making it possible to improve burn-through resistance in all welding positions, including difficult positions such as vertical welding and overhead welding. If added in excess, inclusions will increase, so the Ca content (Wire) The content of Ca is set to 3.00% by mass or less. It is more preferable that the content is 1.00% by mass or less, and further more preferable that the content is 0.30% by mass or less. (Wire)There is no particular meaning in specifying the lower limit value. The Ca source in the wire may be a metal powder of Ca added to the flux, a metal powder of an alloy related to Ca, a compound related to Ca, or Ca contained in the hoop. When Ca is added as a flux, it is preferable to add it as a Ca fluoride powder, since this can further reduce the amount of oxygen in the weld metal.

[0090] (Fe (Wire) :10.0% by mass or less) Fe is an element that improves the ductility of the weld metal. (Wire) If the content of Fe exceeds 10.0 mass %, the hot cracking resistance deteriorates. (Wire) In the wire of this embodiment, the content of Fe is 10.0 mass % or less. (Wire) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and is preferably 9.0% by mass or less, more preferably 8.0% by mass or less. The Fe source in the wire may be a metal powder of Fe added to the flux, a metal powder of an alloy related to Fe, a compound related to Fe, or Fe contained in the hoop. When Fe is added as a flux, it is preferable to add Fe as a metal powder or a metal powder of an alloy related to Fe, such as an Fe-Mn alloy, an Fe-Cr alloy, an Fe-Mo alloy, or an Fe-Ti alloy, in order to improve the deposition amount.

[0091] (B (Wire) :0.10% by mass or less) B is a component that segregates at grain boundaries in the weld metal and has the effect of preventing a decrease in elongation due to hydrogen segregation at grain boundaries. B may be contained in the wire of this embodiment, but if it is contained in excess, there is a risk that hot cracking resistance will decrease. Therefore, in the wire of this embodiment, the content of B (Wire) is preferably 0.10 mass % or less, more preferably 0.05 mass % or less, and even more preferably 0.02 mass % or less. From the viewpoint of suppressing pore defects, the wire of this embodiment does not need to contain B. Therefore, the content B in the wire of this embodiment (Wire)The lower limit of the content B in the wire of this embodiment is not particularly limited. (Wire) may be 0% by mass, or may be, for example, 0.005% by mass or more, or 0.01% by mass or more. The B source in the wire may be a metal powder of B added to the flux, a metal powder of an alloy related to B, a compound related to B, or B contained in the hoop. Examples of the form in which B is added to the flux include an oxide such as BO, and an Fe-B alloy.

[0092] (REM (Wire) :0.1% by mass or less) REM (Rare Earth Metals) refers to rare earth elements, such as Ce and La. REM has a high affinity with S, suppressing the grain boundary segregation of S and also suppressing high temperature cracking caused by S. On the other hand, arc stability is affected by REM (Wire) Since the smaller the added amount of REM is, the better, in order to satisfy the required cracking resistance and arc stability, the total content of REM in the wire is preferably 0.1 mass% or less, and more preferably 0.05 mass% or less. The REM source in the wire may be REM metal powder added to the flux, REM alloy metal powder, REM compound, or REM contained in the hoop.

[0093] (Ba(Wire): 4.00% by mass or less) Ba, contained in the flux mainly as the fluoride BaF2, contributes to the deoxidation of the weld metal and the improvement of welding workability. Therefore, if the above effects are to be obtained, it may be added optionally. However, if excessive Ba is added, arc deflection may occur, which may deteriorate welding workability. Therefore, the Ba content should be limited. (Wire)The content of Ba is preferably 4.00% by mass or less, and more preferably 3.00% by mass or less. When Ba is added to the flux as a fluoride, other elements such as Sr may be substituted, so there is no need to set a lower limit. The Ba source in the wire may be a Ba metal powder added to the flux, a Ba alloy metal powder, a Ba compound, or Ba contained in the hoop, but it is preferable to add BaF2 as a fluoride to the flux.

[0094] (F (Wire) :1.00 mass% or less) F is a component that reduces the hydrogen partial pressure in the arc and inhibits hydrogen penetration into the weld metal, and may be added to the wire of this embodiment. However, if added in excess, there is a risk of increasing porosity defects. Therefore, when F is contained in the wire of this embodiment, the F (Wire) is set to 1.00% by mass or less, preferably 0.50% by mass or less, and more preferably 0.30% by mass or less. From the viewpoint of suppressing pore defects, the wire of this embodiment does not need to contain F, and therefore, the lower limit of the F content of the wire of this embodiment is not particularly limited. That is, the F content of the wire of this embodiment may be 0 mass %, or may be, for example, 0.05 mass % or more, or 0.10 mass % or more. It is preferable that all of the F sources in the wire are derived from fluorides, such as BaF2, SrF2, Na3AlF6, NaF, CaF2, AlF3, K2SiF6, and MgF2, and the wire may contain one or more of these.

[0095] (W (Wire) :5.00% by mass or less) W is a component that improves the strength of the weld metal, but if the content is excessive, there is a risk that the hot cracking resistance will decrease. Therefore, in the wire of this embodiment, the content of W (Wire)is preferably 5.00% by mass or less, more preferably 4.50% by mass or less, and even more preferably 4.00% by mass or less. Since W can be used arbitrarily for strength adjustment, there is no need to specify a lower limit. However, when used to improve strength, it is preferably 1.00% by mass or more, more preferably 1.20% by mass or more, and even more preferably 1.50% by mass or more. Examples of W sources in the wire include metal powder of W added to the flux, metal powder of an alloy related to W, a compound related to W, or W contained in the hoop.

[0096] (Nb (Wire) :0.50% by mass or less) Nb is an element added to Ni-based alloys to improve their strength, but if added in excess, the resistance to hot cracking will decrease. (Wire) The Nb content is suppressed to 0.50% or less. (Wire) is more preferably 0.10% by mass or less, and even more preferably 0.05% by mass or less. The Nb source in the wire may be metal powder of Nb added to the flux, metal powder of an Nb alloy, a Nb compound, or Nb contained in the hoop. For example, the form of Nb contained in the flux may be simple metal Nb, an Fe-Nb alloy, Nb2O5, etc.

[0097] (V (Wire) :0.050% by mass or less) If the amount of V in the wire exceeds 0.050 mass %, V may combine with Ni to form a low melting point compound, which may result in a decrease in hot cracking resistance. (Wire) It is preferable to suppress the content of Si to 0.050 mass % or less.

[0098] (Cu (Wire) :2.0 mass% or less) Cu is an element that contributes to improving the strength of the weld metal. It may be contained to satisfy the strength range required for welding nickel and nickel alloys. Cu content in the wire (Wire)is preferably 2.0% by mass or less, and more preferably 1.0% by mass or less. The Cu source in the wire includes Cu metal powder added to the flux, Cu alloy metal powder, Cu compounds, Cu contained in the hoop, and also Cu plating on the wire surface.

[0099] (Total of alkali metals: 3% by mass or less) The alkali metal element acts as an arc stabilizer. The alkali metal in this embodiment is based on metal powder and compounds containing one or more alkali metal elements. Examples of alkali metal elements include K, Li, and Na. The total content of alkali metals in the wire refers to the total content of alkali metals in the wire converted from metal powder and compounds composed of alkali metal elements. From the viewpoint of making it easier to adjust the melt properties to be favorable for improving the bead shape, the total content of alkali metals in the wire is preferably 3 mass% or less, and more preferably 2 mass% or less, relative to the total mass of the wire.

[0100] (Ni (Wire) :45~75% by mass) Ni alloys with various metals to impart excellent mechanical properties and corrosion resistance to the weld metal. If the Ni content of the wire of this embodiment is less than 45 mass%, a stable austenite structure will not be formed when the weld metal is diluted. On the other hand, if the Ni content exceeds 75 mass%, the amount of other alloy elements added will be insufficient, making it impossible to ensure mechanical properties. Therefore, the Ni content of the wire of this embodiment is set to 45 to 75 mass%. In addition, in the wire of this embodiment, the Ni content (Wire) is preferably 47% by mass or more, more preferably 50% by mass or more, and is preferably 70% by mass or less, more preferably 65% ​​by mass or less. The Ni source in the wire may be Ni metal powder added to the flux, Ni-based alloy metal powder, Ni-based compound, or Ni contained in the hoop. An example of Ni-based alloy metal powder is Ni-Mo alloy.

[0101] (Remainder: O, N and inevitable impurities) In this embodiment, the remainder excluding the above elements is preferably O, N, and unavoidable impurities. Impurities refer to elements that are not intentionally added, and examples of elements other than the above include Sn, Co, Sb, As, and Ta. The total content of impurities in the wire is preferably 0.5% by mass or less, and more preferably 0.3% by mass or less.

[0102] The flux-cored wire that can be used in this embodiment has an outer sheath filled with flux, and it is preferable that the outer sheath be formed from a nickel alloy strip from the standpoints of availability and economy.

[0103] <Welded metal> It is preferable that the composition range is that of JIS Z 3335:2021 TNi1013 or JIS Z 3335:2021 TNi6275, specifically, in mass%, C (METAL) :≦0.10%, Si (METAL) :≦1.0%, Mn (METAL) :≦3.0%, P (METAL) :≦0.020%, S (METAL) :≦0.015% Ni (METAL) :≧50.0%, Cu (METAL) :≦0.5%, Cr (METAL) : 4.0~16.5%, Fe (METAL) :≦10.0%, Mo (METAL) :15.0~19.0%, W (METAL) :≦2.0 to 4.5%, other optional elements≦0.50%, the balance being impurities.

[0104] <Learning device> In this embodiment, as described above, at least the set value or correction value of the weaving width is calculated based on the values ​​of the plate thickness, groove depth, or estimated weld metal height, but the molten pool during welding may be observed using a visual sensor or the like, and the welding conditions may be further corrected according to the state of the molten pool.

[0105] There are no particular restrictions on which set values ​​of the welding conditions are corrected. For example, the weaving width condition may be corrected, or the torch angle may be corrected. Other corrections such as the welding current and arc voltage may also be performed. The above-described molten pool condition can be determined by extracting characteristic points of the molten pool. While there is no particular restriction on the extraction method, it is preferable to extract the characteristic points using a learning device from the viewpoint of extraction accuracy. An example of this embodiment will be described below.

[0106] In the following description of the learning device, "learning" or "machine learning" refers to generating a "trained model" by performing learning using training data and an arbitrary learning algorithm. The trained model is updated as needed as learning progresses using multiple pieces of training data, and its output changes even for the same input. Therefore, the trained model is not limited to a specific state at any point in time. Here, a model used in learning will be referred to as a "learning model," and a learning model that has undergone a certain level of learning will be referred to as a "trained model."

[0107] The trained model may be stored in the portable welding robot 100 or the control device 600. The trained model may be stored in a device that can communicate with the portable welding robot 100 or the control device 600. An example of a device that can communicate with the portable welding robot 100 or the control device 600 is a PC.

[0108] Specific examples of "training data" will be described later, but the configuration may vary depending on the learning algorithm used. When performing cross-validation or the like, the training data may include training data used for the training itself, validation data used for validating the trained model, and test data used for testing the trained model. In the following description, the term "training data" will be used to refer collectively to data related to training, and the term "training data" will be used to refer to data used when performing the training itself. Note that it is not intended to clearly classify the training data into training data, validation data, and test data; for example, depending on the methods of training, validation, and testing, all of the training data may also be training data.

[0109] An example of the configuration of a system including a learning device will be illustrated with reference to Fig. 1. The system including the learning device includes a welding system 50, as well as a visual sensor and a data processing device, which are not shown.

[0110] FIG. 9 is a perspective view illustrating an exemplary placement position of a visual sensor according to an embodiment of the present disclosure. In this embodiment, the workpiece Wo is a butt joint. The workpiece Wo is made of two metal plates W1 and W2, which are butted together across a groove. Since this embodiment is in a vertical position, the welding direction will be described as being upward. A ceramic backing material 14 is attached to the backside of the two butted metal plates. A metal backing material may be used on the backside, or no backing material may be used. Therefore, the material of the backing material is not particularly limited and may vary depending on the material of the workpiece Wo. In a butt joint, arc welding is performed in one direction along the groove. Hereinafter, the direction in which welding proceeds is referred to as the "welding direction." In FIG. 9, the direction in which welding proceeds is indicated by an arrow. Therefore, the welding torch 200 is positioned behind the visual sensor 700, i.e., on the side opposite the welding direction.

[0111] In this embodiment, the workpiece Wo is placed horizontally with the surface to be welded facing vertically upward. Therefore, the portable welding robot 100 welds the workpiece Wo from above. For example, as shown in FIG. 9, the visual sensor 700 may be placed diagonally above the welding position of the workpiece Wo.

[0112] FIG. 10 is a diagram illustrating an image captured by a visual sensor according to an embodiment of the present disclosure. The imaging range of the visual sensor 700 includes the welding position of the workpiece Wo and captures an image of the welding position during arc welding. The captured image includes the molten pool, welding wire, and arc. The visual sensor 700 in this embodiment can continuously capture still images of, for example, 1024 x 768 pixels. In other words, the visual sensor 700 can capture welding images as moving images. The resolution of the still images captured by the visual sensor 700 is not particularly limited. For example, if the visual sensor 700 is configured with multiple cameras, each of the multiple cameras may capture welding images with different resolutions. Furthermore, preprocessing, such as extracting an arbitrary feature region from the captured welding image, may be performed to shorten processing time before inputting the image into the trained model described below. The arbitrary feature region may be a fixed-size range positioned so that a predetermined region is located at the center. The size of the arbitrary feature region may also be changed depending on the welding situation.

[0113] <Configuration of data processing device> 11 is a schematic diagram showing an example configuration of a data processing device according to an embodiment of the present disclosure. The data processing device 800 is configured, for example, by a computer. The computer is configured to include a main body 810, an input unit 820, and a display unit 830. The main body 810 is configured to include a CPU 811, a ROM 812, a RAM 813, a nonvolatile storage device 814, an input / output interface 815, a communication interface 816, a video output interface 817, and a calculation unit 818. The CPU 811, the ROM 812, the RAM 813, the nonvolatile storage device 814, the input / output interface 815, the communication interface 816, the video output interface 817, and the calculation unit 818 are connected to each other via buses or signal lines so as to be able to communicate with each other.

[0114] The calculation unit 818 may be a program executed by the CPU 811. In this case, a program having a function corresponding to the calculation unit 818 is stored in, for example, the nonvolatile storage device 814, and the CPU 811 reads and executes the program.

[0115] The nonvolatile storage device 814 stores a learning program 814A that performs deep learning using collected or acquired learning data, a trained model 814B that is generated through the execution of the learning program 814A, an information generation program 814C that generates evaluation feature information related to welding using the trained model 814B, and image data 814D. In addition, an operating system and application programs are also installed in the nonvolatile storage device 814.

[0116] The data processing device 800 realizes various functions by the execution of a program by the CPU 811. In this embodiment, the data processing device 800 realizes a function of generating a trained model through machine learning and a function of performing various processes during actual welding using the trained model. The details of these functions will be described later. The data processing device 800 may be divided into two parts: a function of generating a trained model and a function of executing control processing based on information output from the trained model during actual welding. From the perspective of versatility, it is more preferable to divide the data processing device 800 into parts according to each function. The ROM 812 stores a basic input output system (BIOS) executed by the CPU 811, etc. The RAM 813 is used as a work area for programs read from the non-volatile storage device 814.

[0117] The input / output interface 815 is connected to an input unit 820 that is composed of a keyboard, a mouse, etc. The visual sensor 700 is also connected to the input / output interface 815. Image data output from the visual sensor 700 is provided to the CPU 811 via the input / output interface 815. The communication interface 816 is a communication module for wired or wireless communication. The video output interface 817 is connected to a display unit 830 that is composed of, for example, a liquid crystal display or an organic EL (Electro-Luminescence) display, and outputs a video signal corresponding to the video data provided by the CPU 811 to the display unit 830.

[0118] The data processing device 800 may be integrated with the control device 600.

[0119] <Generating a trained model> Hereinafter, in this embodiment, feature points to be extracted from image data and a trained model that extracts feature points will be described. Fig. 12 is an explanatory diagram conceptually illustrating a generation process of a trained model 814B according to an embodiment of the present disclosure. The trained model 814B in this embodiment is configured by a convolutional neural network, and has a network configuration in which one or more convolutional layers and pooling layers are stacked to perform one or more layers of full connection.

[0120] In the learning stage, an error is calculated based on the output from the fully connected layer and the welding information serving as training data, and the neural network is updated using the error backpropagation method to reduce this error, thereby generating a trained model.

[0121] The generated trained model 814B receives image data output from the visual sensor 700 as input and outputs feature points related to various welding information that appear in the image data. In this embodiment, the image data input to the trained model 814B includes at least the molten pool, the welding wire 211, and the arc as objects (targets), and feature points obtained from each of these objects or from between multiple objects are extracted. Then, based on the extracted feature points, it becomes possible to obtain welding information such as arc stability, deposition amount, arc tracking status, and penetration level in real time. Note that this image data may hereinafter be referred to as a "welding image."

[0122] In this embodiment, the feature points related to the welding information are the tip of the welding wire 211 (wire tip), the center point of the arc (arc center), the positions of the left and right tips of the molten pool, and the positions of the left and right ends of the molten pool. The feature points used as teaching data are input by the operator by specifying specific positions on the welding image according to instructions on an operation screen that supports the teaching work.

[0123] FIG. 13 is a diagram illustrating an example of a screen used for a teaching operation according to an embodiment of the present disclosure. The welding image shown in FIG. 13 includes a molten pool 15, a welding wire 211, and an arc 16. In FIG. 12, the molten pool 15 is shaded. FIG. 14 is an explanatory diagram illustrating a specific example of a welding image obtained by welding according to an embodiment of the present disclosure and example welding information within the welding image. For ease of explanation, positions corresponding to the coordinates indicated by feature points are depicted on the welding image. As described above, the image has coordinates, which form a coordinate plane consisting of two axes, the X-axis and the Y-axis. In this embodiment, the visual sensor 700 is installed so that the weld line direction and the X-axis direction are parallel. Therefore, in this embodiment, the X-axis direction may be referred to as the weld line direction. Furthermore, the Y-axis direction is perpendicular to the X-axis, i.e., the groove width direction, which is perpendicular to the weld line. Therefore, the Y-axis direction may be referred to as the groove width direction. In addition, since the X axis along which the portable welding robot 100 of this embodiment moves is the direction of the weld line, the X axis along which the portable welding robot moves and the X axis on the welding image also have the same direction, and it can also be said that the Y axis along which the portable welding robot moves and the Y axis on the welding image are also the same.

[0124] In this embodiment, the operator instructs the following characteristic points: the coordinate position of the arc center (ArcX, ArcY), the coordinate position of the wire tip (WireX, WireY), the coordinate position of the left edge of the weld pool (Pool_Lead_Lx, Pool_Lead_Ly), the coordinate position of the right edge of the weld pool (Pool_Lead_Rx, Pool_Lead_Ry), the coordinate position of the left edge of the weld pool (Pool_Ly), and the coordinate position of the right edge of the weld pool (Pool_Ry). The operator inputs welding information by specifying a specific position on the screen. The coordinates defining the boundary between the welding wire 211 and the arc are an example of the position coordinates of the wire tip. The left edge of the weld pool, the right edge of the weld pool, the left edge, and the right edge of the weld pool are examples of characteristic points related to the behavior of the weld pool 15. For example, the width of the weld pool 15 can be calculated by knowing the characteristic points of the left edge and the right edge of the weld pool.

[0125] In this embodiment, it is sufficient to use at least two time series data: the difference in the X direction between any predetermined weld pool tip position and the wire tip position (hereinafter referred to as "Lead X") is calculated and sampled, and the difference between the left end of the weld pool tip and the right end of the weld pool tip (hereinafter referred to as "Lead W") is calculated and sampled. Note that the number of samples per unit time is not particularly limited.

[0126] The calculation unit 818 uses, for example, the coordinate position of the left end of the molten pool tip (Pool_Lead_Lx, Pool_Lead_Ly), the coordinate position of the right end of the molten pool tip (Pool_Lead_Rx, Pool_Lead_Ry), and the coordinate position of the wire tip (WireX, WireY) from among the feature points output from the learning device.

[0127] The calculation unit 818 calculates Lead X. For example, if the position of the tip of the molten pool is on the right end side, the calculation unit 818 calculates Lead X as the difference in the X-axis direction between the coordinate position of the right end of the tip of the molten pool and the coordinate position of the wire tip ("Pool_Lead_Rx" - "WireX").

[0128] The calculation unit 818 calculates Lead W. For example, the calculation unit 818 may calculate Lead W as the difference in the Y-axis direction between the coordinate position of the left end of the tip of the molten pool and the coordinate position of the right end of the tip of the molten pool ("Pool_Lead_Ry" - "Pool_Lead_Ly"), or may calculate it as the difference between the coordinate position of the left end of the molten pool (Pool_Ly) and the coordinate position of the right end of the molten pool (Pool_Ry).

[0129] The distances of Lead X and Lead W calculated by the calculation unit 818 may be expressed in units of pixels, which may be converted into any unit such as "mm" or "cm".

[0130] By collecting time-series data of Lead X and Lead W, the state of the molten pool can be determined, and depending on the determination results, any welding conditions can be corrected and automatic control can be performed to return the molten pool to a stable state. For example, by monitoring the time-series data of Lead X, the control device 600 can determine that the molten pool is expanding when the value of Lead X exceeds a predetermined threshold, and control the welding speed to increase or the torch angle to tilt in the retreating direction so that the arc hits the groove.

[0131] In the present embodiment, as an example, LeadX and LeadW are calculated and automatic welding is performed based on the time series data, but the present invention is not limited to the time series data of LeadX and LeadW.

[0132] <First Example> FIG. 15 illustrates a first example of welding according to an embodiment of the present disclosure.

[0133] The first example shows the results of an appearance inspection performed when a gap is present, in which the weaving width is set according to the control method of the welding robot or control device according to the embodiment of the present disclosure, and actual welding is performed. Note that the presence of a gap means that the gap is larger than the wire diameter of the welding wire.

[0134] The experimental conditions were as follows. First, Hastelloy-based Ni-based flux-cored wire was used as the welding wire. Mild steel was used as the steel plate to be welded. The welding position was vertical welding. The welding conditions, such as current and voltage, were set to optimal values ​​within the ranges of welding current: 150 to 200 A, arc voltage: 22 to 30 V, and welding speed: 5 to 28 cm / min.

[0135] Test numbers 1 to 9 are examples, and test numbers 10 to 17 are comparative examples. The execution information shows the numbers for groove depth, weld reinforcement, weld metal height, Gap1, Gap2, and average gap. The units of execution information are all mm. The weld metal height is the sum of the groove depth and weld reinforcement height. In addition, touch sensing was used to obtain gap values ​​at two locations at different depths, which are designated as Gap1 and Gap2. The average gap is the average value of Gap1 and Gap2.

[0136] In this embodiment, the average Gap is used as a reference value for calculating the weaving width correction value and the ratio of weaving width / Gap. However, the gap at each position in the depth direction, i.e., Gap1 and Gap2, may be used as a reference value to calculate the weaving width at each position in the depth direction.

[0137] The weaving width correction value, which is the correction value, and the weaving width to be set or corrected are both shown. The units for the weaving width correction value and the weaving width are both mm.

[0138] The correction value shown is the weaving width correction value calculated in step S4 of FIG. 8. The weaving width value is obtained by adding twice the weaving width correction value to the average gap. Note that since weaving is performed so that it extends to both ends of the gap, not just one end, twice the weaving width correction value is added to the average gap. The numerical values ​​in FIG. 15 are rounded to the second decimal place. For example, in Example 1, when the average gap + 2 × weaving width correction value is calculated, the result is 3.6 + 2 × 2.2 = 8.0, which appears to be an error from the stated weaving width of 7.9, but this is due to the effect of rounding and is actually calculated correctly.

[0139] The ratio of weaving width / gap is calculated by dividing the weaving width by the average gap and multiplying the result by 100, and is expressed in %.

[0140] Para 1 and Para 2 are abbreviations for Parameter 1 and Parameter 2, respectively. Parameter 1 is the value obtained by calculating 14.3 × groove depth + 351.5, and this value of Parameter 1 is the first value described above. Parameter 2 is the value obtained by calculating 6.8 × groove depth + 122.5, and this value of Parameter 2 is the second value described above.

[0141] Reference is now made to Fig. 16, which is a plot diagram corresponding to an embodiment of the present disclosure. In the plot diagram, the horizontal axis represents the groove depth and the vertical axis represents the weaving width / average gap, and each example and comparative example are plotted. A circle indicates that the welding result was good, and a cross indicates that the welding result was not good.

[0142] The applicant performed multiple welding runs while repeatedly changing the values ​​of the construction information, such as test number 1 to test number 17 in Figure 15, to check the welding results and create the plot diagram shown in Figure 16. As a result, it was found that the circles were plotted so as to be sandwiched between the lower straight line formed by connecting the lower x marks and the upper straight line formed by connecting the upper x marks.

[0143] The lower line is y=6.7701x+122.46. The upper line is y=14.318x+351.56. Note that x represents the horizontal axis and y represents the vertical axis.

[0144] Returning to Figure 15, parameter 1 corresponds to the upper straight line. Parameter 2 corresponds to the lower straight line. Note that parameters 1 and 2 are also rounded to one decimal place.

[0145] Based on the plot diagram in FIG. 16, if the weaving width / average gap shown in FIG. 15 is smaller than parameter 1 and larger than parameter 2, the welding results plotted with circles in FIG. 16 can be good.

[0146] Conversely to the above, the numbers in FIG. 15 where the weaving width / average gap is greater than parameter 1 and the numbers where the weaving width / average gap is smaller than parameter 2 are shown in bold and underlined.

[0147] The welding results in Figure 15 are rated A, B, and C for each test number. Rating A indicates that the welding was successful and the bead appearance was good. Rating B indicates that the welding was successful, but the bead appearance was not good. Rating C indicates that the welding was not successful at all.

[0148] As is clear from Fig. 15, for welding results rated C, the weaving width / average gap is greater than parameter 1 or smaller than parameter 2. In other words, if parameter 1 and parameter 2 are used as the standards, the evaluation of welding results based on actual tests will match.

[0149] Therefore, when there is a gap, that is, when the gap is larger than the wire diameter of the welding wire, it is preferable to determine the weaving width so that W / G, which is the ratio of W, which means the weaving width, to G, which means the gap, is equal to or smaller than 14.3×A+351.5 and equal to or larger than 6.8×A+122.5, where A is the value of the groove depth, the estimated weld metal height—the reinforcement height, or the plate thickness.

[0150] In the above-described embodiment, parameters 1 and 2 are calculated based on the "groove depth." However, parameters 1 and 2 may be set based on other values. For example, parameters 1 and 2 may be set based on the "estimated weld metal height - reinforcement height." Alternatively, parameters 1 and 2 may be set based on the "plate thickness." That is, when the gap is larger than the wire diameter of the welding wire, the weaving width is calculated so that W / G, which is the ratio of W, which represents the weaving width, to G, which represents the gap, is equal to or smaller than a first value and equal to or larger than a second value. The first value and the second value may be values ​​based on the groove depth. The first value and the second value may be values ​​based on the estimated weld metal height - reinforcement height. The first value and the second value may be values ​​based on the plate thickness.

[0151] <Second Example> FIG. 17 illustrates a second example of welding according to an embodiment of the present disclosure.

[0152] The second example shows the results of a visual inspection performed when the gap value was set to 0, i.e., when there was no gap, by setting the weaving width according to the control method for the welding robot or control device according to an embodiment of the present disclosure, and then actually performing welding. Note that when the gap is smaller than the wire diameter of the welding wire, the gap value is set to 0.

[0153] The implementation conditions are the same as those in the first embodiment.

[0154] Test numbers 18 to 20 are examples. The meaning of each column in Fig. 17 is the same as in Fig. 15, so a detailed explanation will be omitted.

[0155] Since there is no gap, the values ​​of Gap1, Gap2, and average Gap are set to 0. Therefore, the ratio of weaving width / Gap is not shown because it would be meaningless as it would be divided by 0. Parameter 1 and parameter 2, which are to be compared with the ratio of weaving width / Gap, are also not shown.

[0156] The welding results were graded B for test numbers 18 and 20, and graded A for test number 19.

[0157] Based on FIG. 17, when there is no gap, that is, when the gap is smaller than the wire diameter of the welding wire, it is preferable to determine the weaving width based on a preset value for the amplitude DB or the like.

[0158] As described above, the present specification discloses the following:

[0159] (1) A control method for a welding robot or a control device for GMAW in which a groove is provided in a workpiece, the workpiece and a welding wire have different compositions, and the welding wire contains 5% or more Ni, A construction information setting process for setting construction information including at least one of a plate thickness, a groove depth, and an estimated weld metal height, and at least one of a gap and a groove width at a center position of a previously calculated layer height; a welding condition setting and correction process for calculating a weaving width based on the construction information before or during welding, and setting or correcting welding conditions including at least the weaving width; A method for controlling a welding robot or a control device, comprising: According to this configuration, excellent welding quality can be obtained even when the GMAW method, which has high welding efficiency, is used in welding when the materials to be welded and the welding wire have different compositions and the welding wire contains 5% or more Ni.

[0160] (2) At least one set value of the plate thickness, the groove depth, or the estimated weld metal height is set as a threshold value, A threshold value and a DB in which a weaving width correction value is defined for each threshold value or for each interval between the threshold values ​​are stored in advance in a storage device, In the welding condition setting correction step, The weaving width correction value is extracted from the DB based on one value of the plate thickness, the groove depth, or the estimated weld metal height among the construction information and the threshold value; The weaving width is calculated based on the gap value or the groove width value at the center position of the layer height calculated in advance and the weaving width correction value. The control method according to (1). According to this configuration, the weaving width can be corrected using the correction value stored in advance.

[0161] (3) The control method according to (2), characterized in that the calculation of the weaving width includes any one of addition, subtraction, or multiplication of the gap value or the groove width at the center position of the layer height calculated in advance and the weaving width correction value. According to this configuration, the weaving width can be flexibly calculated by using any one of addition, subtraction, and multiplication between the gap or the groove width at the center position of the previously calculated layer height and the weaving width correction value.

[0162] (4) Further comprising a sensing step of detecting construction information before welding; In the sensing step, at least one value selected from the plate thickness, the groove depth, the weld length, the groove angle, and the gap value is calculated based on the detection result of the sensing, The control method according to any one of (1) to (3), characterized in that the calculated value is determined as the setting value to be set in the construction information setting step. According to this configuration, sensing such as touch sensing can be performed and construction information can be set from the sensing results, making it possible to easily handle welding of various steel plates.

[0163] (5) In the welding condition setting correction step, Based on the construction information, the welding conditions Setting or correcting At least one condition is the torch angle. of Setting or correction Do The control method according to any one of (1) to (4), characterized in that: According to this configuration, by setting the torch angle, it is possible to control the arc so that it reaches the steel sheet.

[0164] (6) The control method according to (5), characterized in that when the welding position in the execution information is vertical, the torch angle condition is set or corrected within a range of sweepback angle. According to this configuration, by setting the torch angle downward, i.e., at a sweepback angle, the arc can be controlled so as to reach the steel sheet.

[0165] (7) A welding phenomenon information acquisition step of acquiring welding phenomenon information during welding by a sensor, The control method according to any one of (1) to (6), characterized in that in the welding condition setting and correction process, the welding conditions are set or corrected based on the acquired welding phenomenon information. According to this configuration, by updating the welding conditions during welding based on the acquired welding phenomenon information, it is possible to perform more appropriate welding.

[0166] (8) The welding robot, the control device, or a device capable of communicating with the welding robot or the control device has a trained model generated so as to use the welding phenomenon information as input data and to output feature information acquired from the welding phenomenon information, In the welding condition setting and correction step, the welding conditions are set or corrected based on feature information output from the trained model by inputting the welding phenomenon information. The control method according to (7), characterized by: With this configuration, welding conditions can be automatically set by utilizing the trained model.

[0167] (9) A control device for controlling a welding robot in GMAW in which a groove is provided in a workpiece, the workpiece and a welding wire have different compositions, and the welding wire contains 5% or more Ni, A construction information setting function for setting construction information including at least one of a plate thickness, a groove depth, and an estimated weld metal height, and at least one of a gap and a groove width at a center position of a previously calculated layer height; a welding condition setting and correction function that calculates a weaving width based on the construction information before or during welding and sets or corrects welding conditions including at least the weaving width; A control device comprising: According to this configuration, excellent welding quality can be obtained even when the GMAW method, which has high welding efficiency, is used in welding when the materials to be welded and the welding wire have different compositions and the welding wire contains 5% or more Ni.

[0168] (10) A welding system for controlling a welding robot in GMAW in which a groove is provided in a workpiece, the workpiece and a welding wire have different compositions, and the welding wire contains 5% or more Ni, The welding machine includes at least a control device and a welding power source, The control device A construction information setting function for setting construction information including at least one of a plate thickness, a groove depth, and an estimated weld metal height, and at least one of a gap and a groove width at a center position of a previously calculated layer height; a welding condition setting and correction function that calculates a weaving width based on the construction information before or during welding and sets or corrects welding conditions including at least the weaving width; A welding system comprising: According to this configuration, excellent welding quality can be obtained even when the GMAW method, which has high welding efficiency, is used in welding when the materials to be welded and the welding wire have different compositions and the welding wire contains 5% or more Ni.

[0169] (11) A control program for controlling a welding robot in GMAW in which a groove is provided in a workpiece, the workpiece and a welding wire have different compositions, and the welding wire contains 5% or more Ni, the program comprising: A construction information setting function for setting construction information including at least one of a plate thickness, a groove depth, and an estimated weld metal height, and at least one of a gap and a groove width at a center position of a previously calculated layer height; a welding condition setting and correction function that calculates a weaving width based on the construction information before or during welding and sets or corrects welding conditions including at least the weaving width; A control program comprising: According to this configuration, excellent welding quality can be obtained even when the GMAW method, which has high welding efficiency, is used in welding when the materials to be welded and the welding wire have different compositions and the welding wire contains 5% or more Ni.

[0170] (12) A welding method relating to GMAW in which a groove is provided in a workpiece, the workpiece and the welding wire have different compositions, and the welding wire contains 5% or more Ni, A construction information setting process for setting construction information including at least one of a plate thickness, a groove depth, and an estimated weld metal height, and at least one of a gap and a groove width at a center position of a previously calculated layer height; a welding condition setting and correction process for calculating a weaving width based on the construction information before or during welding, and setting or correcting welding conditions including at least the weaving width, In the welding condition setting correction step, When the value of the gap or the value of the groove width at the center position of the previously calculated layer height is smaller than the wire diameter of the welding wire, a weaving width is calculated based on a preset value, a welding method, characterized in that, when the gap value or the previously calculated groove width value at the center position of the layer height is larger than a wire diameter of the welding wire, a weaving width is calculated so that W / G, which is a ratio of W meaning the weaving width to G meaning the gap value or the previously calculated groove width value at the center position of the layer height, is not more than a first value and not less than a second value. However, the first value and the second value are values ​​based on the groove depth, the estimated weld metal height - the reinforcement height, or the plate thickness. According to this configuration, excellent welding quality can be obtained even when the GMAW method, which has high welding efficiency, is used in welding when the materials to be welded and the welding wire have different compositions and the welding wire contains 5% or more Ni.

[0171] (13) When the welding position is vertical in the construction information, The welding method according to (12), wherein in the welding condition setting and correcting step, at least a torch angle condition is set or corrected within a range of a sweepback angle as one of the welding conditions. According to this configuration, when the welding position is vertical, the torch angle is set downward, i.e., at a sweepback angle, so that the arc can be controlled to reach the steel plate.

[0172] (14) When the groove depth, the estimated weld metal height - the reinforcement height, or the plate thickness is A, the first value is 14.3×A+351.5, The welding method according to (12) or (13), wherein the second value is 6.8×A+122.5. According to this configuration, excellent welding quality can be obtained even when the GMAW method, which has high welding efficiency, is used in welding when the composition of the material to be welded and the welding wire are different and the welding wire contains 5% or more Ni.

[0173] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present disclosure is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure. Furthermore, the components of the above-described embodiments may be combined in any manner without departing from the spirit of the disclosure.

[0174] The order of execution of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings, is not specifically stated as "before," "prior to," etc., and can be realized in any order unless the output of a previous process is used in a subsequent process. Even if the operational flow in the claims, specifications, and drawings is explained using "first," "next," etc. for convenience, this does not mean that it is essential to perform the process in that order. [Industrial Applicability]

[0175] The present disclosure is useful for a control method, a control device, a welding system, a control program, and a welding method that can obtain excellent welding quality even when a GMAW method with high deposition efficiency is used in welding when the compositions of the workpiece and the welding wire are different. [Explanation of symbols]

[0176] 10 Bevel 14 Backing material 15 Molten pool 16 Arc 50 Welding System 100 Portable welding robot 110 Robot body 112 Main body 113 Slide support 114 Fixed arm part 116 Welding torch rotation drive unit 120 guide rail 130 Torch connection part 132, 134 Torch clamp 140 parts 150 Cable Clamp 160 Handles on both sides 168 Rotational Axis 169 Sliding Table 169a long groove 170 crank 171 connecting pin 172 Fixing pin 180 Approximate linear movement mechanism 181 X-axis movement mechanism 182 Y-axis movement mechanism 183 Z-axis movement mechanism 200 welding torch 210 nozzle 211 Welding Wire 300 Feeding device 400 Welding Power Source 410, 430 power cable 420 Conduit Tube 500 Shielding gas supply source 510 Gas Tube 600 control device 601 Data storage unit 602 Bevel shape information calculation unit 603 Welding condition acquisition unit 604 Control Unit 610 Robot control cable 620 Power supply control cable 700 Visual Sensor 800 Data Processing Device 810 main unit 814 Non-volatile storage device 814A Study Program 814B model 814C Information Generation Program 814D Image data 815 Input / Output Interface 816 Communication Interface 817 Video Output Interface 818 Calculation Unit 820 Input section 830 Display section

Claims

1. A control method for a welding robot or a control device for GMAW in which a groove is provided in a workpiece, the workpiece and a welding wire have different compositions, and the welding wire contains 5% or more of Ni, A construction information setting process for setting construction information including at least one of a plate thickness, a groove depth, and an estimated weld metal height, and at least one of a gap and a groove width at a center position of a previously calculated layer height; a welding condition setting and correction process for calculating a weaving width based on the construction information before or during welding, and setting or correcting welding conditions including at least the weaving width; and At least one set value of the plate thickness, the groove depth, or the estimated weld metal height is set as a threshold value, and a DB in which the threshold value and a weaving width correction value are defined for each threshold value or for each interval between the threshold values ​​are stored in a storage device in advance, In the welding condition setting correction step, The weaving width correction value is extracted from the DB based on one value of the plate thickness, the groove depth, or the estimated weld metal height among the construction information and the threshold value; The weaving width is calculated based on the gap value or the groove width value at the center position of the layer height calculated in advance and the weaving width correction value. A control method for a welding robot or a control device.

2. 2. The control method according to claim 1, wherein the calculation of the weaving width includes any one of addition, subtraction, or multiplication of the gap value or the groove width at the center position of the previously calculated layer height and the weaving width correction value.

3. The method further includes a sensing step of detecting construction information before welding, In the sensing step, at least one value selected from the plate thickness, the groove depth, the weld length, the groove angle, and the gap value is calculated based on the detection result of the sensing, 3. The control method according to claim 1, wherein the calculated value is determined as the set value to be set in the construction information setting step.

4. A control method for a welding robot or a control device for GMAW in which a groove is provided in a workpiece, the workpiece and a welding wire have different compositions, and the welding wire contains 5% or more of Ni, A construction information setting process for setting construction information including at least one of a plate thickness, a groove depth, and an estimated weld metal height, and at least one of a gap and a groove width at a center position of a previously calculated layer height; a welding condition setting and correction process for calculating a weaving width based on the construction information before or during welding, and setting or correcting welding conditions including at least the weaving width; and In the welding condition setting correction step, Based on the execution information, at least a torch angle condition is set or corrected as one of the settings or corrections of the welding conditions; A control method for a welding robot or a control device, characterized in that, when the welding posture in the construction information is vertical, the torch angle condition is set or corrected within a range of a sweepback angle.

5. a welding phenomenon information acquisition step of acquiring welding phenomenon information during welding by a sensor, 3. The control method according to claim 1, wherein in the welding condition setting and correcting step, the welding conditions are set or corrected based on the acquired welding phenomenon information.

6. the welding robot, the control device, or a device capable of communicating with the welding robot or the control device has a trained model generated so as to use the welding phenomenon information as input data and to output feature information acquired from the welding phenomenon information; 6. The control method according to claim 5, wherein in the welding condition setting and correction process, the welding conditions are set or corrected based on feature information output from the trained model by inputting the welding phenomenon information.

7. A control device for controlling a welding robot in GMAW when a groove is provided in a workpiece, the workpiece and a welding wire have different compositions, and the welding wire contains 5% or more of Ni, A construction information setting function for setting construction information including at least one of a plate thickness, a groove depth, and an estimated weld metal height, and at least one of a gap and a groove width at a center position of a previously calculated layer height; a welding condition setting and correction function that calculates a weaving width based on the construction information before or during welding and sets or corrects welding conditions including at least the weaving width; and At least one set value of the plate thickness, the groove depth, or the estimated weld metal height is set as a threshold value, and a DB in which the threshold value and a weaving width correction value are defined for each threshold value or for each interval between the threshold values ​​are stored in a storage device in advance, In the welding condition setting correction function, The weaving width correction value is extracted from the DB based on one value of the plate thickness, the groove depth, or the estimated weld metal height among the construction information and the threshold value; A control device that calculates the weaving width based on the gap value or a groove width value at a central position of a layer height calculated in advance and the weaving width correction value.

8. A welding system for controlling a welding robot for GMAW in which a groove is provided in a workpiece, the workpiece and a welding wire have different compositions, and the welding wire contains 5% or more of Ni, The welding device includes at least a control device and a welding power source, The control device A construction information setting function for setting construction information including at least one of a plate thickness, a groove depth, and an estimated weld metal height, and at least one of a gap and a groove width at a center position of a previously calculated layer height; a welding condition setting and correction function that calculates a weaving width based on the construction information before or during welding and sets or corrects welding conditions including at least the weaving width; and At least one set value of the plate thickness, the groove depth, or the estimated weld metal height is set as a threshold value, and a DB in which the threshold value and a weaving width correction value are defined for each threshold value or for each interval between the threshold values ​​are stored in a storage device in advance, In the welding condition setting correction function, The weaving width correction value is extracted from the DB based on one value of the plate thickness, the groove depth, or the estimated weld metal height among the construction information and the threshold value; A welding system characterized in that the weaving width is calculated based on the gap value or a groove width value at a center position of a layer height calculated in advance and the weaving width correction value.

9. A control program for controlling a welding robot for GMAW in a case where a groove is provided in a workpiece, the workpiece and a welding wire have different compositions, and the welding wire contains 5% or more of Ni, A construction information setting function for setting construction information including at least one of a plate thickness, a groove depth, and an estimated weld metal height, and at least one of a gap and a groove width at a center position of a previously calculated layer height; a welding condition setting and correction function that calculates a weaving width based on the construction information before or during welding and sets or corrects welding conditions including at least the weaving width; and At least one set value of the plate thickness, the groove depth, or the estimated weld metal height is set as a threshold value, and a DB in which the threshold value and a weaving width correction value are defined for each threshold value or for each interval between the threshold values ​​are stored in a storage device in advance, In the welding condition setting correction function, The weaving width correction value is extracted from the DB based on one value of the plate thickness, the groove depth, or the estimated weld metal height among the construction information and the threshold value; A control program for calculating the weaving width based on the gap value or the groove width value at the center position of the layer height calculated in advance and the weaving width correction value.

10. A welding method for GMAW in which a groove is provided in a workpiece, the workpiece and a welding wire have different compositions, and the welding wire contains 5% or more of Ni, A construction information setting process for setting construction information including at least one of a plate thickness, a groove depth, and an estimated weld metal height, and at least one of a gap and a groove width at a center position of a previously calculated layer height; a welding condition setting and correction process for calculating a weaving width based on the construction information before or during welding, and setting or correcting welding conditions including at least the weaving width, In the welding condition setting correction step, When the value of the gap or the value of the groove width at the center position of the previously calculated layer height is smaller than the wire diameter of the welding wire, a weaving width is calculated based on a preset value, When the value of the gap or the value of the groove width at the center position of the previously calculated layer height is larger than the wire diameter of the welding wire, a weaving width is calculated so that W / G, which is a ratio of W meaning the weaving width to G meaning the value of the gap or the value of the groove width at the center position of the previously calculated layer height, is not more than a first value and not less than a second value; When the welding position is vertical in the construction information, The welding method according to claim 1, wherein in the welding condition setting and correcting step, at least a torch angle condition is set or corrected within a range of a sweepback angle as one of the welding conditions. However, the first value and the second value are values ​​based on the groove depth, the estimated weld metal height - the reinforcement height, or the plate thickness.

11. A welding method for GMAW in which a groove is provided in a workpiece, the workpiece and a welding wire have different compositions, and the welding wire contains 5% or more of Ni, A construction information setting process for setting construction information including at least one of a plate thickness, a groove depth, and an estimated weld metal height, and at least one of a gap and a groove width at a center position of a previously calculated layer height; a welding condition setting and correction process for calculating a weaving width based on the construction information before or during welding, and setting or correcting welding conditions including at least the weaving width, In the welding condition setting correction step, When the value of the gap or the value of the groove width at the center position of the previously calculated layer height is smaller than the wire diameter of the welding wire, a weaving width is calculated based on a preset value, When the value of the gap or the value of the groove width at the center position of the previously calculated layer height is larger than the wire diameter of the welding wire, a weaving width is calculated so that W / G, which is a ratio of W meaning the weaving width to G meaning the value of the gap or the value of the groove width at the center position of the previously calculated layer height, is not more than a first value and not less than a second value; When the groove depth, the estimated weld metal height - the excess metal height, or the plate thickness is A, the first value is 14.3×A+351.5; 2. A welding method, wherein the second value is 6.8×A+122.

5. However, the first value and the second value are values ​​based on the groove depth, the estimated weld metal height - the reinforcement height, or the plate thickness.

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