Control device, control method, and program

Abstract

To provide a control device, a control method, and a program that enable stable welding.SOLUTION: Provided is a control device that controls a welding or fusion device that performs welding or fusion along a peripheral direction of a piping. The control device controls the welding or fusion device to perform welding or fusion by changing a welding or fusion condition while axially rotating the piping. The welding is keyhole welding.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] In the automatic circumferential TIG welding equipment for fixed pipes, complete back bead welding is performed using a heat conduction type non-keyhole. The welding torch positions are downward, downward, vertical, upward and all positions, and optimal welding conditions are required for each position. Therefore, the circumference of the fixed pipe is divided into 4 or 8 parts, and the welding conditions are controlled individually to ensure a stable back bead.

[0003] In the automatic TIG welding equipment for the circumference of a rotating pipe, the torch position is fixed. The welding torch is directed downward and is not controlled separately.

[0004] Welding of rotary pipes using keyhole TIG welding is disclosed in US Pat. Nos. 5,399,433 and 5,443,623. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 59-16681 [Patent Document 2] Japanese Patent Application Publication No. 49-77857 Summary of the Invention [Problem to be solved by the invention]

[0006] When welding horizontal rotary pipes using keyhole TIG welding, maintaining the keyhole requires arc force in the high welding current area, high speed rotation to accommodate the high welding current, and adjustment of welding conditions for each welding area. The automatic circumferential TIG welding device for rotating pipes disclosed in Patent Document 1 is controlled under constant welding conditions, with the rotation direction horizontal and the torch position downward. Therefore, the molten pool advances and the shape and size of the keyhole cannot be maintained, which causes the keyhole to become clogged and the back bead to not be produced, making it impossible to ensure a stable back bead in the lap and crater parts. In the plasma welding method disclosed in Patent Document 2, the rotation direction is vertical, the torch position is downward, and the welding current is low at 150 A, so the molten pool does not advance and there is no need to increase the rotation speed. An object of the present invention is to provide a control device, a control method, and a program that enable stable welding. [Means for solving the problem]

[0007] One aspect of the present invention is a control device that controls a welding or cutting device that performs welding or cutting along the circumferential direction of a pipe, and controls the welding or cutting device to change the welding or cutting conditions while rotating the pipe around its axis to perform welding or cutting. Effect of the Invention

[0008] According to the present invention, stable welding can be achieved. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram showing a configuration of an automatic pipe welding system according to an embodiment of the present invention; [Diagram 2] FIG. 4 is a diagram illustrating the position of a welding head. [Diagram 3] FIG. 2 shows an area of ​​a pipe to be welded. [Figure 4] FIG. 13 is a diagram showing a change in the type of arc current. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0011] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 is a perspective view showing a configuration of an automatic pipe welding system 100 according to an embodiment of the present invention. The automatic welding system 100 includes an automatic pipe welding device 1 and a control device 20. The control device 20 controls the automatic pipe welding device 1 to weld a pipe P.

[0012] In the drawings shown below, an XYZ Cartesian coordinate system is set, with the X-axis direction representing the front-to-back direction (width direction) of the automatic welding equipment 1 along the circumferential direction of the pipe P, the Y-axis direction representing the left-to-right direction (depth direction) of the automatic welding equipment 1 along the axial direction of the pipe P, and the Z-axis direction representing the up-down direction (height direction) of the automatic welding equipment 1.

[0013] As shown in FIG. 1, an automatic welding device 1 of this embodiment automatically performs welding along the circumferential direction of a pipe P while rotating the pipe P about its axis.

[0014] Specifically, this automatic welding device 1 is equipped with a welding head 2 that is positioned on the outer circumferential surface of a pipe P and performs welding on the pipe P that rotates about its axis, and a head support mechanism 3 that supports the welding head 2 so that it can move up and down relative to the pipe P and in the front-rear direction along the circumferential direction of the pipe P. The head support mechanism 3 is attached to a frame (not shown) of this automatic welding device 1.

[0015] The welding head 2 is, for example, a commonly used TIG welding torch (non-consumable welding torch). The welding head 2 has a non-consumable electrode 4 that generates an arc current between the welding head 2 and the pipe P, and a torch nozzle 5 that emits shielding gas toward a molten pool generated by the arc.

[0016] FIG. 2 is a diagram for explaining the position of the welding head 2. It is desirable that the welding head 2 is located between 12:30 and 2:30 with respect to the pipe P. Explaining this using the XYZ Cartesian coordinate system, when the pipe P rotates counterclockwise when viewed in the positive direction along the Y axis as shown in FIG. 2, it is desirable that the welding head 2 is located in the region of (X, Z) = (-cosθ, sinθ) (15°≦θ≦75°). When the welding head 2 is located at the 0 o'clock position, that is, (X, Z) = (0, 1), a convex bead is generated and the molten molten pool is likely to drip in the opposite direction to the traveling direction. By positioning the welding head 2 in the region shown in FIG. 2, it is possible to prevent the molten pool from dripping in the opposite direction to the traveling direction due to the generation of a convex bead.

[0017] A wire aim guide 6 is attached to the welding head 2. The wire aim guide 6 has a feed head 6a that guides the filler wire W and feeds the filler wire W from its tip side, and a liner (also called a conduit) 6b ​​that feeds the filler wire W toward the tip of the feed head 6a.

[0018] The feed head 6a has a nozzle shape with its tip end extended toward the tip end of the non-consumable electrode 4. The wire aim guide 6 has a rotation mechanism 6c that rotatably supports the feed head 6a, making the angle of the feed head 6a adjustable. The liner 6b is connected to a wire feeder (not shown), which can automatically feed the filler wire W.

[0019] The wire aim guide 6 is attached to the front side of the welding head 2 via a guide support mechanism 7. The guide support mechanism 7 has a height adjustment unit 7a that adjusts the position of the wire aim guide 6 in the up-down direction (Z-axis direction) relative to the welding head 2, and a depth adjustment unit 7b that adjusts the position of the wire aim guide 6 in the left-right direction (Y-axis direction) relative to the welding head 2.

[0020] In the guide support mechanism 7, the vertical and horizontal positions of the wire aim guide 6 relative to the welding head 2 can be adjusted using the height adjustment section 7a and the depth adjustment section 7b, and then the position can be fixed.

[0021] In addition, an after-shield mechanism 8 is attached to the welding head 2. The after-shield mechanism 8 has an after-shield cover 8a that covers the tip side of the welding head 2 rearward in the weld line direction, and emits an after-shield gas from inside this after-shield cover 8a toward the weld bead formed immediately after welding of the piping P.

[0022] The head support mechanism 3 has an up-down slider 3a that supports the welding head 2 so that it can move freely in the up-down direction (Z-axis direction) relative to the pipe P, a front-to-back slider 3b that supports the welding head 2 so that it can move freely in the front-to-back direction (X-axis direction) relative to the pipe P, a height adjustment unit 3c that adjusts the position of the welding head 2 in the up-down direction (X-axis direction) relative to the pipe P, and a depth adjustment unit 3d that adjusts the position of the welding head 2 in the left-right direction (Y-axis direction) relative to the pipe P.

[0023] In the head support mechanism 3, the up-down slider 3a and the front-rear slider 3b allow the welding head 2 to be constantly moved in the up-down and front-rear directions relative to the pipe P. In the head support mechanism 3, the height adjustment unit 3c and the depth adjustment unit 3d allow the position of the welding head 2 in the up-down and left-right directions relative to the pipe P to be adjusted, and then the position can be fixed.

[0024] The head support mechanism 3 has a pair of rotating rollers 9 aligned in the circumferential direction of the pipe P. The pair of rotating rollers 9 are attached to the lower ends of the upper and lower sliders 3a via mounting plates 10 so as to keep the distance between the outer circumferential surface of the pipe P and the tip of the welding head 2 constant.

[0025] The pair of rotating rollers 9 are axially supported by the mounting plate 10, and are thereby capable of rotating while being in sliding contact with the outer circumferential surface of the pipe P. In addition, the pair of rotating rollers 9 are pressed against the outer circumferential surface of the pipe P by the weight of the welding head 2 itself.

[0026] In addition, the head support mechanism 3 has an offset adjustment unit 11 that adjusts the front-to-rear position (offset) of the welding head 2 with respect to the top of the pipe P. The offset adjustment unit 11 makes it possible to change the attachment position of the attachment plate 10 with respect to the lower end of the vertical slider 3a in the front-to-rear direction.

[0027] In the head support mechanism 3, the offset adjustment portion 11 can be used to adjust the position of the welding head 2 in the front-to-rear direction relative to the top of the pipe P, and then the position can be fixed.

[0028] A method of controlling the automatic welding device 1 by the control device 20 will be described below. The control device 20 controls the magnitude of the arc current generated by the non-consumable electrode 4. The control device 20 changes the welding conditions while controlling the rotating roller 9 to rotate the pipe P about its axis, and causes the welding head 2 to perform welding along the circumferential direction of the pipe P. The control device 20 may change the welding conditions while the rotating roller 9 makes one revolution of the pipe P, or may change the welding conditions for each revolution of the pipe P. However, in order to prevent the molten pool from dripping, it is preferable to change the welding conditions during one revolution of the pipe P.

[0029] The welding conditions are at least one of the wire feed speed by the wire aim guide 6, the rotation speed of the pipe P caused by the rotation of the rotary roller 9, and the type of arc current generated by the non-consumable electrode 4. The control device 20 sets the wire feed speed, the rotation speed of the pipe P, and the type of arc current individually.

[0030] The control device 20 changes the welding conditions, for example, by changing the rotation speed or rotation angle of the rotating rollers 9. The control device 20 can change the welding conditions by changing the rotation speed or rotation angle of the rotating rollers 9, thereby changing the welding conditions by the rotation speed of the pipe P. The control device 20 controls the amount of heat input by individually setting the wire feed speed and the magnitude of the arc current according to the rotation speed of the pipe P, and can suppress the occurrence of burn-through and internal defects during lap crater treatment during main welding. The control device 20 can keep the excess weld height the same, for example, by slowing down the wire feed speed when the rotation speed of the pipe P slows down. Also, the control device 20 can keep the excess weld height the same, for example, by speeding up the wire feed speed when the rotation speed of the pipe P speeds up.

[0031] The rotation speed of the pipe P is preferably 40 cm / min or more and 150 cm / min or less. The rotation speed of the pipe P is more preferably 50 cm / min or more and 100 cm / min or less.

[0032] Furthermore, the control device 20 can change the welding conditions by changing the number of rotations or the rotation angle of the rotating rollers 9, thereby changing the welding conditions for each region to be welded of the pipe P. For example, as shown in Fig. 3, the control device 20 can divide the region to be welded of the pipe P into regions A1 to A4, and change the welding conditions for each region.

[0033] The type of the arc current is at least one of an initial current, an upslope current, a main welding current, a downslope current, and a crater current. FIG. 4 is a diagram showing a change in the type of the arc current. 4, the vertical axis represents the magnitude of the arc current, and the horizontal axis represents time. Controller 20 changes the arc current in the following order: initial current, upslope current, main welding current, downslope current, and crater current.

[0034] The initial current and upslope current are the currents that are started up to reach the main welding current. The main welding current is the arc current when welding is performed. The downslope current and crater current are the currents that are started down after welding is completed. When the piping P is a carbon steel pipe, the current is started down using a downslope current, which gradually decreases in magnitude after rotation has stopped, thereby preventing blowholes from occurring during the final crater treatment.

[0035] The control device 20 may change the magnitude of the main welding current. The magnitude of the main welding current is preferably 350 A or more and 1000 A or less. Furthermore, the magnitude of the main welding current is more preferably 400 A or more and 800 A or less.

[0036] Other Embodiments Although one embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to the above, and various design changes, etc. are possible within the scope that does not deviate from the gist of the present invention. In the above embodiment, an example is given of automatically performing TIG welding along the circumferential direction of the pipe P while rotating the pipe P around its axis, but the welding method is not limited to non-consumable electrode gas-shielded arc welding such as TIG welding, and may be consumable electrode gas-shielded arc welding such as MIG welding, MAG welding, or carbon dioxide arc welding.

[0037] In addition, in the above embodiment, the present invention is described as being applied to an automatic pipe welding device that automatically welds a pipe along its circumferential direction using a welding head while rotating the pipe about its axis. However, the present invention can also be applied to an automatic pipe cutting device that automatically cuts a pipe along its circumferential direction using a cutting head while rotating the pipe about its axis.

[0038] Furthermore, the plasma arc is not limited to the above-mentioned welding applications, but is also used for brazing workpieces, joining, cutting, thermal spraying, melting furnaces, etc. In the present invention, such applications other than welding are also treated as a form of welding.

[0039] The whole or part of the functions of the control device 20 in the above-mentioned embodiment may be realized by a computer. In that case, a program for realizing the functions may be recorded in a computer-readable recording medium, and the program recorded in the recording medium may be read into a computer system and executed to realize the functions. The term "computer system" as used herein includes an OS and hardware of peripheral devices. The term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, and recording devices such as hard disks built into a computer system. The term "computer-readable recording medium" may also include a medium that dynamically holds a program for a short period of time, such as a communication line when a program is transmitted via a network such as the Internet or a communication line such as a telephone line, and a medium that holds a program for a certain period of time, such as a volatile memory inside a computer system that is a server or client in that case. The above-mentioned program may be a program for realizing a part of the functions described above, or may be a program that can realize the functions described above in combination with a program already recorded in the computer system. The whole or part of the functions of the control device 20 may also be realized using a programmable logic device such as an FPGA (Field Programmable Gate Array). [Explanation of symbols]

[0040] 1...automatic welding device 2...welding head (TIG welding torch) 3...head support mechanism 6...wire aim guide 7...guide support mechanism 8...aftershield mechanism 9...rotating roller 10...mounting plate 11...offset adjustment section 100...automatic welding system 20...control device A...area P...piping C...central axis S...rotation axis

Claims

1. A control device for controlling a welding or melting device that performs welding or melting along a circumferential direction of a pipe, The welding or melting device is controlled to perform welding or melting by changing welding or melting conditions while rotating the pipe around its axis; The welding is a keyhole welding. Control device.

2. The welding or melt cutting includes a lap and crater process after going around the pipe once. The control device according to claim 1 .

3. The welding or cutting conditions are at least one of a wire feed speed, a rotation speed of the pipe, and a type of arc current in welding or cutting. The control device according to claim 1 or 2.

4. Changing the welding conditions during the main welding in the welding. The control device according to claim 1 or 2.

5. A control method for controlling a welding or melting device that performs welding or melting along a circumferential direction of a pipe, comprising: The welding or melting device is controlled to perform welding or melting by changing welding or melting conditions while rotating the pipe around its axis; The welding is a keyhole welding. Control methods.

Images