JPS6144595B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a new automatic welding method, especially when the target parts to be welded, such as piping, are in environments harmful to the human body such as radiation, harmful gases, high temperatures, etc., or in confined spaces. The present invention relates to a remote-controlled automatic welding method that is suitable for welding where there are problems such as the operator being unable to access the welding area, or the operator not being able to enter the welding area because the welding is performed in a vacuum vessel.

With conventional automatic welding methods, when the groove shape is simple and the number of laminated layers is small, satisfactory welding can be achieved by controlling the welding conditions and torch position set in advance. Furthermore, when welding large-diameter, thick-walled fixed pipes, the number of laminated layers is several tens of layers, and the welding position changes along the circumference of the pipe, and the welding direction changes accordingly, making automation difficult and difficult for skilled workers. Welding work is carried out under the supervision of trained workers. However, if the welding location is in a hazardous environment or in a narrow space and cannot be accessed by the worker, there is a drawback that the worker cannot monitor the welding location and cannot guarantee welding quality.

Recently, research has been actively conducted on performing remote automatic welding by programming various welding conditions into a computer and adapting the welding conditions in response to changes in the conditions of the welded part. In addition, during such automatic welding, television cameras and television receivers have come to be used to monitor and record the welding state (Japanese Patent Laid-Open No. 159446/1983, Japanese Patent Laid-Open No. 159446/1983
(See Publication No. 90442).

However, in conventional methods, even if various welding conditions are programmed, the electrode tip position and weaving width often deviate from the original correct conditions due to changes in the composition of the material to be welded. That is,
It has been found that these two conditions cannot be determined solely by program settings.

An object of the present invention is to determine, for example, the position of the electrode in the groove width direction and the weaving width, or the position of the electron beam irradiation position and the groove width direction, based on information about the welding groove and the torch position shown on the TV image. An object of the present invention is to provide a remote-controlled automatic welding method that obtains good welding quality by correcting the weaving width.

The present invention does not require monitoring during welding.In other words, the range of fluctuation can be predicted, and the parameter group [A] can be operated according to a pre-input program.
As a result, the welding voltage, welding current, welding speed, filler wire feeding speed and weaving speed are automatically set by the program control device,
As a parameter group [B] related to the relative position of the welding groove and the torch in the width direction of the welding groove, the position of the electrode tip in the width direction of the welding groove and the weaving width are program-controlled, and the parameters are transmitted from a television camera attached to the welding head. The quality of the welded part is guaranteed by performing welding while manually correcting the above-mentioned parameter group [B] using the received image on the receiver.

Parameter group [A] includes welding current, welding voltage, welding speed, welding wire feeding speed, and weaving speed that are determined in advance in preliminary experiments. These parameter group [A] are set as a program since there is no need to change them during welding.

Parameter group [B] is the groove spacing, which changes due to missetting of the piping, distortion of the piping due to welding heat, changes in welding conditions, etc. during the welding process.
The height and width of the weld metal fluctuate during welding, and even slight variations can have a significant effect on the welding result, so the weaving width and position of the torch must be constantly corrected using ITV images. Therefore, the weaving width of the torch and the position in the width direction of the welding groove are set as parameter group [B], and if automatic welding is impossible, they are corrected manually while looking at the ITV image.

As mentioned above, in the case of MIG or TIG welding,
Welding conditions that are essentially affected by internal factors of the welded part, such as thermal expansion and deformation due to heating of the groove, and the presence or absence of defects such as cavities in the welded material, that is, fluctuations from the programmed conditions The position of the electrode tip in the groove width direction and the weaving width, which are parameters whose width cannot be predicted, are corrected visually or by computer processing based on television image information. Other parameters such as arc voltage, welding current, welding speed, filler wire feeding speed, and weaving speed are not affected by internal factors of the material to be welded, so welding is performed under conditions programmed in the computer.

On the other hand, when the present invention is applied to electron beam welding, the parameter group [B] that is affected by fluctuations in internal factors of the material to be welded is the relationship between the electron beam irradiation position and the position in the groove width direction. Welding is performed while the relationship or weaving width is preprogrammed and manually corrected based on television image information,
For the other parameter group [A], welding is performed under predetermined conditions programmed into the computer.

That is, in electron beam welding, parameter group [A]
Parameter group [B] is the beam current accelerating voltage, welding speed, and focal position in the depth direction of the beam.
is the relative position between the beam irradiation position and the position in the groove width direction or the weaving width.

This will be explained below with reference to the drawings.

Figure 1 shows the overall configuration of the present invention, including weaving around the pipe 9, an AVC (arc voltage control) head 4, and an ITV (industrial television).
A light receiving section 1, a wire feeder, a truck traveling head 10, and a groove sensor 11 are attached.

The weaving/AVC head 4 weaves a welding torch from side to side perpendicular to the welding line, and the height of the torch (electrode) is automatically adjusted so that the welding voltage is constant.

The wire feeding/truck running head 10 drives the weaving/AVC head 4 and the groove sensor 11, and further includes a feeding device for welding filler wire 7.

The groove sensor 11 detects the position of the welding groove and the height of the weld metal using a magnetic sensor or the like.

These weaving/AVC head 4, wire feeding/truck running head 10, and groove sensor 1
1 are connected together and move circumferentially on guide rails arranged around the circumference of the tube 9.

The program circuit 12 is provided with setting dials for each circuit indicated by the white circles in the figure, and these dials are used to control the AVC circuit 13, wire feeding circuit 14, trolley running circuit 15, and welding current control circuit 16.
can be programmed in advance. The black circles in the figure indicate the positions in the longitudinal direction of welding, and each welding condition is set at each position using the corresponding white circle setting dial. The weaving circuit 5 automatically operates the weaving width according to a preset program based on a signal from the groove sensor 11. The electrode position correction circuit 6 is configured to manually correct the position of the welding torch 3 in the groove width direction and the weaving width based on information from the ITV image section 2 obtained by the ITV light receiving section 1.

FIG. 2 shows details of the weaving circuit 5 and electrode position correction circuit 6 of parameter group [B]. The speed of the DC motor 19 for moving the torch is servoed by the output of the tachogenerator 20, the amplifier 22, and the transistor power circuit 21, and the output of the torch position potentiometer 18 and the ITV image section of FIG. The position of the torch 3 is set according to the program based on the difference between the set values of the left end setting potentiometer 28, the center setting potentiometer 29 and the right end setting potentiometer 30 obtained by the information.

The switching circuit 24 sends signals to the left end setting switch 25, the center 26, and the right end 27 transistors in order to switch the position of the torch 3 in the groove width direction to the left or right. The left end setting switch 25 is a circuit switch that stops the electrode 34 at the left end of the weld metal in the groove, the center setting switch 26 is a circuit switch that stops the electrode 34 at the center, and the right end setting switch 27 is a circuit switch that stops the electrode 34 at the right end.

When there is no need to weave the electrode 34 at the start of welding, welding is performed at the position set by the central setting switch 26. When the electrode 34 needs to weave left and right in the second and subsequent layers, the left and right positions are set by the left end setting switch 25 and the right end setting switch 27, and weaving is performed between them. The above settings were originally set automatically based on a signal that was automatically analyzed from the image taken by the ITV receiver (TV camera) 1, but the deformation of the groove and the formation of the weld metal became unstable. In this case, each position is manually adjusted using the setting dial of the potentiometer, and welding is performed by the signals from the setting switches 25 to 27.

The left end setting potentiometer 28 is a potentiometer that sets the left end of the weld metal in the groove, the center setting potentiometer 29 is a center setting potentiometer, and the right end setting potentiometer 30 is a potentiometer that sets the right end.

When weaving is not necessary, the position of the electrode 34 in the groove direction is set by the central setting potentiometer 29. When weaving is required for two or more layers, the left end of the weaving is set by the left end setting potentiometer 28, and the right end is set by the right end setting potentiometer 30.

Normally, when stable welding is being performed, this parameter group [B] is automatically set by the TIV light receiving unit 1 and groove sensor 11 according to the program, but if the piping is deformed or the welding is unstable. When automatic welding is not possible, parameter group [B] is switched to manual and the operator can manually set it while viewing the television image, allowing highly reliable welding to be performed remotely.

FIG. 3 is a configuration diagram showing the arrangement near the welding torch, and the position at the tip of the electrode 34 is guided to the ITV light receiving part 1 by the reflector 31 from the opposite direction of the filler wire supplied from the torch holder 32 at the rear in the welding direction. The image is then electronically transmitted to the ITV image section 2. An arc is generated between the electrode 34 and the pipe groove, and welding is performed. Inert gas such as Ar and He is ejected from the welding torch 3 to prevent oxidation of the welded part. The welding torch 3 is fixed to the weaving/AVC head 4 by a torch holder 33. welding torch 3
is weaved left and right, and the height of electrode 34 is AVC.
The welding voltage is detected by the circuit and the height is automatically set. The filler wire 7 to the weld is automatically fed through a wire feeding tip 32. The welding situation is reflected by the reflecting mirror 31 and guided to the ITV light receiving section, and becomes an image.

FIG. 4 is an explanatory diagram of the image of the ITV image unit 2, which shows the groove 35 of the pipe 9. In the first layer welding, the tip of the electrode 34 should accurately follow the position _P0 , and For multilayer welding, weaving width P ₁ ~
Adjustment can be made by the electrode position correction circuit 6 so as to accurately track P ₂ .

FIG. 5 is a configuration diagram in which the parameter group [B] for the optical system in the overall configuration of FIG. 1 is controlled by a computer. The signal from the ITV light receiving unit 1 is subjected to processing such as binarization in the signal processing unit 38, and then processed by the central processing unit 40 of the computer into the storage unit 39, and by the program 41 on the scanning line a-b of the ITV image unit 2. Weaving circuit 5 calculates the position of beads etc.
to move torch 3.

In FIG. 5, the image signal on the ab line obtained by the ITV light receiving section 1 is processed in the ITV image section 2, the groove position and the weld metal width are analyzed, and a signal is sent to the weaving circuit 5 to start welding. This shows a circuit that does this automatically.

As described above, according to the present invention, in arc welding, arc voltage, welding current, welding speed, filler wire feeding speed, and weaving speed are automatically set as parameter group [A] that does not need to be monitored by the welding operator. While setting from a program, the position of the electrode tip in the groove width direction and the weaving width, which need to be monitored during welding, are determined by the electrode position correction mechanism while monitoring images on a TV or by driving a servo mechanism using computer processing. Since it is possible to perform accurate welding even by remote control by making adjustments, it is possible to exhibit an excellent effect of guaranteeing the quality of the welded part without welding defects (for example, poor penetration).

According to the present invention, the following remarkable effects can also be obtained.

(1) The welding conditions to be adjusted, in other words, the number of adjustment knobs, can be significantly reduced, and the welding equipment can be easily operated.

(2) Since the number of knobs to be adjusted is reduced and the adjustment width is narrowed (you only need to adjust the deviation from the program), the welding machine will not run out of control.

(3) Parameters whose fluctuation range can be predicted are operated according to the program, and the operator is prevented from changing the parameters during certain welding operations.
The welding machine will not run out of control.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the overall configuration of the present invention, Fig. 2 is a weaving circuit diagram for adjusting the torch position, and Fig. 3 is a weaving circuit diagram for adjusting the torch position.
4 is an explanatory diagram of the ITV image and FIG. 5 is a diagram of the configuration of the image analysis. 1...ITV light receiving section, 2...ITV image section, 3...
Welding torch, 4... Weaving/AVC head, 5... Weaving circuit, 6... Electrode position correction circuit, 7... Filler wire, 8... Clamp, 9... Piping, 10... Wire feeding/truck running Head, 11...Closed tip sensor, 12...Program circuit, 13...AVC circuit, 14...Wire feeding circuit, 15...Bolly running circuit, 16...Welding current control circuit, 17...Welding power source, 18...Torch position potentiometer, 19...DC motor, 2
0...Tachometer generator, 21...Transistor power circuit, 22, 23...Amplifier, 24...Switching circuit, 25...Left end setting switch, 26...Center setting switch, 27...Right end setting switch, 2
8...Left end setting potentiometer, 29...Center setting potentiometer, 30...Right end setting potentiometer, 31...Reflector, 32...Wire feeding chip, 33...Torch holder, 34... Electrode, 35... Groove, 36... Bead, 37... Arc, 38... Signal processing section, 39... Storage section, 4
0...Central processing unit, 41...Program.

Claims (1)

[Claims] 1. Parameter group [A] of welding current, welding voltage, welding speed, and other necessary welding conditions, and parameter group [B] regarding the relative position of the weld groove and torch in the weld groove width direction. In a method of automatically welding by setting a program and determining welding conditions suitable for each position of the welded part based on the signal, the parameter group [A] is maintained at the programmed conditions during welding, and the television camera is A remote-controlled automatic welding method, characterized in that welding is performed while manually correcting the parameter group [B] based on the information regarding the relative position of the welding groove and the torch that is thus captured. 2 TIG or MIG welding in which the above parameter group [A] is welding voltage, welding current, welding speed, filler wire feeding speed, and weaving speed, and parameter group [B] is the electrode tip position or weaving width in the welding groove width direction. 2. The remote-controlled automatic welding method according to claim 1, wherein said automatic welding is carried out at a remote control automatic welding method. 3 The above parameter group [A] is the beam current accelerating voltage, welding speed, and the focus position of the beam in the depth direction, and the above parameter group [B] is the relative position of the beam irradiation position and the weld groove in the weld development width direction or 2. The remote-controlled automatic welding method according to claim 1, wherein the automatic welding is performed by electron beam welding with a weaving width.