JP2002079373A - Method and device for controlling position of welding for high-frequency pulse arc welding - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To solve the problems of high-frequency pulse arc welding and prevent deflection of the arc to the side wall in the groove, and to determine the arc length and welding position during welding. An object of the present invention is to provide a welding position control method and a welding position control device that enable control, stabilize high-frequency pulse arc welding, and obtain a good weld. A narrow gap welding or overlay welding method for generating a high-frequency pulse arc between a non-consumable electrode and a base material to be welded and feeding a welding wire during the high-frequency pulse arc to perform welding. A high-frequency pulse arc is generated between the non-consumable electrode and the base material to be welded, and the arc length during welding is measured by a CCD camera image or a non-contact displacement meter, and controlled to a predetermined arc length. While measuring the arc voltage during welding, calculating the effective arc voltage, determining whether the arc effective voltage is a predetermined arc effective voltage, and opening the non-consumable electrode based on the effective arc voltage. Controls the in-point or lap position and performs narrow gap welding or overlay welding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a welding position control method and apparatus in high frequency pulse arc welding.

[0002]

2. Description of the Related Art Generally, TIG arc welding and plasma arc welding are known as welding methods using non-consumable electrodes containing tungsten as a main component. The high-frequency pulse arc welding method is a type of TIG arc welding. As described in JP-A-49-115957 and JP-A-11-28568, as the peak value of the high-frequency pulse current increases, The contraction force due to the electromagnetic pinch force increases, and the rigidity of the arc increases.

[0003] It is also known that when the pulse current is increased in frequency, the arc pressure increases. Due to the vibration effect of high frequency and high peak pulse current,
It is said that there is an effect of reducing the size of the crystal grains in the welded portion and reducing blowholes. Another method is to use a mixed gas of argon and hydrogen (or helium) as a shielding gas and to contract the arc by using a gas pinch force to increase the rigidity of the arc.

[0004] On the other hand, in TIG arc welding and plasma arc welding, the arc voltage during welding is detected and the arc length during welding is controlled to be constant, so that welding operation and welding quality can be improved. Is improved. As a welding control method, as described in JP-A-9-38777 and JP-A-7-16743, an arc voltage during welding is detected and the arc length during welding is made constant. There is a control method.

[0005]

A high-frequency pulse arc is generated between a welded joint having a groove and a non-consumable electrode, and a welding wire is fed during the high-frequency pulse arc to perform welding. In groove welding, the contraction force due to the electromagnetic pinch force increases, the rigidity of the arc increases, the deflection of the arc to the side wall inside the groove is prevented, and narrow groove welding is enabled.

However, in the method of controlling the arc length to be constant by the arc voltage as the welding control, the frequency is 1 KHz.
Since the above high-frequency pulse current is used, the fluctuation of the arc voltage is large, and the welding is unstable. Also, in the groove of the weld joint, the arc voltage further fluctuates because the distance between the side wall and the non-consumable electrode in the groove is short, and since the welding is multilayered, the surface of the weld portion has irregularities, Welding is unstable.

Further, if the arc length is reduced to avoid instability during welding, the non-consumable electrode and the welding wire are likely to come into contact. For these reasons, in the conventional welding control method using the arc voltage, it is difficult to control the narrow groove welding or the overlay welding by the high frequency pulse arc.

An object of the present invention is to make it possible to control the arc length and welding position during welding while preventing deflection of the arc to the side wall in the groove, and to stabilize high frequency pulse arc welding. Another object of the present invention is to provide a welding position control method and a welding position control device in high frequency pulse arc welding in which a good weld can be obtained.

[0009]

An object of the present invention is to provide a high-frequency pulse arc between a non-consumable electrode and a base material to be welded, and a welding wire fed during the high-frequency pulse arc to perform welding. In the groove welding or overlay welding method, a high-frequency pulse arc is generated between the non-consumable electrode and the base material to be welded, and C
The arc length during welding is measured by a CD camera image or a non-contact displacement meter, and the arc voltage during welding is measured while controlling to a predetermined arc length. The problem can be solved by calculating the effective voltage, controlling the in-groove position or the lap position of the non-consumable electrode by the arc effective voltage, and performing narrow groove welding or overlay welding.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the embodiments shown in the drawings. FIG. 1 is a schematic diagram of a welding position control method and a high-frequency pulse arc welding device using the welding position control device of the present invention. The base materials 2a and 2b to be welded are, for example, examples of weld joints of a chemical plant and a nuclear power plant.

The high-frequency pulse arc welding apparatus uses a non-consumable electrode 1 containing tungsten as a main component, and has a torch vertical drive device 7 capable of driving in the vertical direction and a torch drive device capable of driving in the horizontal direction. A welding contact head 6 provided with a left-right movement driving device 8 is provided.

Further, a wire feeding device 5 for feeding a welding wire 4 into an arc 3 generated between the non-consumable electrode 1 and the base materials 2a and 2b, a welding contact head 6 and a wire feeding device. The vehicle includes a traveling vehicle 9 on which the device 5 is mounted, and a traveling rail 10 on which the traveling vehicle 9 travels.

A high frequency pulse arc welding power supply 11 supplies a high frequency pulse welding current to the welding contact head 6. The welding control device 12 includes a high-frequency pulse arc welding power source 11,
The control of the traveling vehicle 9 and the wire feeding device 5 is performed. The welding position control device 22 is provided for controlling the welding contact head 6 provided with the torch vertical drive device 7 and the torch left / right drive device 8 capable of driving in the left-right direction.

The welding device includes a device for supplying shielding gas and cooling water, a control device, and the like.
Since it is not directly related to the present invention, illustration and description are omitted.

A welding position control device 22 for controlling a welding contact head 6 provided with a torch vertical drive device 7 and a torch left / right drive device 8 capable of driving in the left-right direction includes a base material 2a, CCD camera 14 for observing the inside of the gateway 13 of 2b
And a monitor device 1 for monitoring an image of the CCD camera 14
5 and arc 3 during welding based on the image of the CCD camera 14.
An image processing device 16 for measuring the length of the electrode 3 and the position of the non-consumable electrode 1, a discriminating device 17 for discriminating whether or not the length of the arc 3 is a predetermined value, a non-consumable electrode 1 and the base materials 2a, 2b. A measuring device 18 for measuring an arc voltage between the two, a processing device 19 for calculating an effective value of the arc voltage, a determining device 20 for determining whether or not the effective voltage of the arc is a predetermined value, A control device 21 is provided for giving a command signal and a control signal to the torch vertical drive device 7 and for giving a command signal and a control signal to the torch vertical drive device 8. As the CCD camera 14, a non-contact type displacement meter can be used.

A high-frequency pulse arc welding power supply 11 for supplying a high-frequency pulse welding current outputs a high-frequency pulse current waveform having a base current of 10 A or more and a peak current of 300 A or more and a frequency of 1 KHz or more. Lumber 2
A high frequency pulse arc 3 is generated between a and 2b.

[0017] Welding contact head 6 and wire feeder 5
Can travel at an arbitrary set speed on a traveling rail 10 installed along a welding line. A welding robot may be used instead of the traveling cart 9. The welding control device 12 controls the high-frequency pulse arc welding power supply 11, the traveling vehicle 9, and the wire feeding device 5.

Using a high-frequency pulse arc welding power source 11 and a welding control device 12, a welding wire 4 fed from a wire feeding device 5 passes through a wire guide and passes between a non-consumable electrode 1 and base materials 2a and 2b. Sent during the high frequency pulse arc 3;
Melts to form a weld bead.

The base materials 2a and 2b constituting the weld joint include:
A groove 13 having an arbitrary shape is provided, which is heated and melted by the high frequency pulse arc 3 and filled with the molten metal of the welding wire 4 to complete the welding. The image of the CCD camera 14 for observing the arc in the groove 13 during welding, the monitor device 15, and the image processing device 16 measure the length L1 of the arc 3 during welding. The length L1 of the arc 3 is
For example, 1.5 mm.

Further, a discriminating device 17 for discriminating whether the length of the arc 3 is appropriate or not is discriminated whether or not the arc length is a predetermined arc length L0. Directive,
A control device 21 for giving a control signal and a command and a control signal to the right-and-left movement driving device 8 gives a command to a vertically-moving driving device for the welding touch so that the control is performed so that the arc length becomes a predetermined arc length L0. Done.

On the other hand, an arc voltage (va) during welding between the non-consumable electrode 1 and the base materials 2a and 2b is measured by a measuring device 18 for measuring an image and an arc voltage by a CCD camera.
The processing unit 19 for calculating the effective value of the arc voltage calculates the arc effective voltage (Ve).

Further, it is determined whether or not the effective arc voltage ve is a predetermined effective arc voltage Ve ₀ , and a command signal and a control signal are given to the up-and-down moving drive device 7 to A control device 21 for giving a command signal and a control signal to the left and right driving device 8
As a result, a command is sent to the left and right movement driving device 8 of the welding torch, and the horizontal left and right position control of the non-consumable electrode 1 in the groove is performed. If there is no wrap, the length of the top of the groove is about 4m
m, when the diameter of the electrode is about 2 mm, the gap between the electrode and the groove inner peripheral wall is controlled to about 1 mm.

As described above, the length of the arc 3 during welding is set to CC.
By controlling the image based on the image of the D camera 14, it is possible to keep the arc length constant at all times, even if the surface of the welding portion has irregularities or within the groove, By controlling using the voltage (Ve) and the image of the CCD camera 14, the left and right positions of the non-consumable electrode 1 in the groove can be controlled.

[0024] Thereby, the welding work of narrow point welding by high frequency pulse arc welding can be simplified, the usability can be improved, and a good welded portion can be obtained.

According to the welding position control method of the present invention, the CCD
The control accuracy is improved by alternately controlling the length of the arc 3 during welding based on the image of the camera 14 and the left and right position control of the non-consumable electrode 1 based on the effective arc voltage ve and the image of the CCD camera 14. Thus, a high-precision, high-quality welded joint can be obtained.

FIG. 2 shows a welding current waveform and an arc voltage waveform at the time of high-frequency pulse arc welding according to the first embodiment. The welding current waveform during high-frequency pulse arc welding of the first embodiment is a high-frequency pulse current having a base current of 10 OA or more and a peak current of 300 A or more, and a frequency of IKHz or more.

The arc voltage waveform at that time is disturbed and largely fluctuates due to irregularities on the surface of the weld, welding in a narrow groove, generation of noise caused by high frequency, and the like. Therefore, in the present invention, the arc voltage Va during welding is measured, the effective value of the arc voltage is calculated based on the measured value, the arc effective voltage Ve is calculated, and the arc effective voltage Ve is determined. It is used to control the horizontal position of the consumable electrode 1 in the horizontal direction.

Since the arc effective voltage Ve has little fluctuation, its control is easy. Similarly, the arc average voltage Vav
e is calculated, and when the arc average voltage Vave is used for controlling the horizontal position of the non-consumable electrode 1 in the horizontal direction, the arc effective voltage Vave
Variation is greater than e, but control is simplified.

According to the method of controlling the left and right positions of the non-consumable electrode 1 based on the effective arc voltage Ve and the image of the CCD camera 14 according to the present invention, the control accuracy is improved. In addition, the arc average voltage Vav
The method of controlling the left and right positions of the non-consumable electrode 1 by e can be easily controlled.

FIG. 3 shows a second embodiment of overlay welding by high frequency pulse arc welding using the method of the present invention. The same reference numerals as those in FIG. 1 indicate the same parts.

In the build-up welding by high-frequency pulse arc welding using the method of the present invention, as shown in FIG. 3, a high-frequency pulse arc welding power supply 11 and a welding control device 12 connect the non-consumable electrode 1 and the base metal 2. A high-frequency pulse arc 3 is generated,
The welding wire 4 fed from the wire feeding device 5 is fed into the high-frequency pulse arc 3 between the non-consumable electrode 1 and the base material 2, and the welding wire 4 is melted to form a weld bead and build-up welding is performed. Is the way.

The control of the lap margin of the lap beads 23 and 24 at the time of overlay welding by high frequency pulse arc welding is performed by controlling the left and right positions of the non-consumable electrode 1 based on the arc effective voltage Ve and the image of the CCD camera 14 in the method of the present invention. In this case, uniform lap beading is possible, welding work is simplified, usability can be improved, and a high-quality overlay weld can be obtained. In the above-described embodiment, a case where a non-consumable electrode is used is shown. However, a consumable electrode can be used. In this case, do not use the welding wire 4,
The electrode for electrodes is a consumable electrode.

In the embodiment of the present invention as described above,
As the method of controlling the arc length, the arc length during welding is controlled by image processing using a CCD camera or a non-contact displacement meter. The fluctuation of the voltage (Va) is reduced, and the position adjustment of the non-consumable electrode in the groove and the lap adjustment of the overlay bead at the time of overlay welding can be performed.

Further, the arc voltage during welding of the present invention is measured, the arc effective voltage is calculated, and it is determined whether or not the arc effective voltage is a predetermined arc effective voltage. The method of controlling the position of the non-consumable electrode in the groove by instructing the left and right driving devices of the image and the welding contact to control the position of the non-consumable electrode in the groove has a small voltage fluctuation, and enables high-precision control. It becomes easy to adjust the position of the consumable electrode and to adjust the lap of the build-up speed during the build-up welding.

Further, the arc voltage during welding is measured, the arc average voltage is calculated, and it is determined whether or not the arc average voltage is a predetermined arc average voltage. The method of controlling the position of the non-consumable electrode in the groove by instructing the left-right movement driving device of the welding torch, although slightly inaccurate, enables simple control.

Further, a high-frequency pulse arc is generated between the non-consumable electrode and the base material to be welded, and the position in the groove of the non-consumable electrode or the lap position for overlay welding is controlled by the image of the CCD camera, and Measure the arc voltage during welding, calculate the arc effective voltage, judge whether it is the predetermined arc effective voltage, and control the arc length during welding by the arc effective voltage. The same effect can be obtained even in the case of using the method.

Further, by using the welding position control method and the welding position control device in the high-frequency pulse arc welding, it is possible to control the welding joint at the narrow end of general welding structures, welding pipes, chemical plants and nuclear power plants. Bath welding, multi-layer bus welding, and overlay welding can be performed satisfactorily, and automation of welding and improvement of welding quality can be achieved.

Further, by using the welding position control method and the welding position control device in the high-frequency pulse arc welding of the present invention, it is possible to manufacture a weld joint having a narrow junction by multi-layer single-bus welding.

[0039]

As described above, according to the present invention, one-pass welding or multilayer multi-bus welding, weld overlaying on narrow-gap welded joints of general welding structures, welding pipes, chemical plants and nuclear power plants. High-frequency pulse arc welding can be performed satisfactorily for welding, position control during welding can be performed with high accuracy, and welding can be automated and welding quality can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic view of a welding position control method of the present invention and a high-frequency pulse arc welding device using the welding position control device.

FIG. 2 is a diagram showing a welding current waveform and an arc voltage waveform during high-frequency pulse arc welding according to the first embodiment.

FIG. 3 is a diagram showing a second embodiment of overlay welding by high-frequency pulse arc welding using the method of the present invention.

[Explanation of Symbols] 1 ... non-consumable electrode, 2, 2a, 2b ... base material, 3 ... arc,
DESCRIPTION OF SYMBOLS 4 ... Welding wire, 5 ... Wire feeding device, 6 ... Welding touch head, 7 ... Touch vertical movement drive device, 8 ... Touch left / right movement drive device, 9 ... Truck, 10 ... Trail ... High frequency pulse arc welding power supply, 12 ... Welding control device, 13
... groove, 14 ... CCD camera, I5 ... monitor device, 16
... image processing device, 17 ... arc length discriminating device, 18 ... arc voltmeter side device, 19 ... arc voltage effective value calculation processing device, 20 ... arc effective voltage discriminating device, 21 ... 1 vertical movement, left and right movement control device, 22 ... welding position control device, 23,
24 ... Rap speed.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yoshinao Urayama 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside the Hitachi Research Laboratory, Hitachi, Ltd. (72) Takao Kumasaka 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture No. 1 Inside Hitachi, Ltd.Hitachi Research Laboratories (72) Inventor Akira Onuma 7-1-1, Omikacho, Hitachi City, Ibaraki Prefecture Inside Hitachi, Ltd. Hitachi Research Laboratory Co., Ltd. (72) Inventor Kunio Miyazaki Hitachi City, Ibaraki Prefecture Omika 7-1-1, Machi-cho, Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Tadashi Takahashi 7-1-1, Omika-cho, Hitachi, Ibaraki F-term, Hitachi Research Laboratory, Hitachi Ltd. F-term (reference) 4E082 AA01 AA11 BA04 EB13 EC00 EC03 EF00

Claims (4)

[Claims] 1. A high-frequency pulse arc is generated between a welding electrode and a base material to be welded, and a welding wire is fed during the high-frequency pulse arc to perform narrow groove welding or overlay welding. At the same time, the arc length during welding is measured using a CCD camera image or a non-contact displacement meter to control the arc length to a predetermined value, and the arc voltage during welding is measured. Calculating the arc effective voltage and controlling the horizontal position or the lap position within the groove of the welding electrode based on the arc effective voltage. Control method. 2. A high-frequency pulse arc is generated between a welding electrode and a base material to be welded, and a welding wire is fed during the high-frequency pulse arc to perform narrow groove welding or overlay welding. At the same time, the arc length during welding is measured using a CCD camera image or a non-contact displacement meter to control the arc length to a predetermined value, and the arc voltage during welding is measured. An arc average voltage is calculated, and the horizontal position in the groove of the welding electrode or the lap position of the overlay welding is controlled by the average voltage. Welding position control method. 3. A narrow gap welding or overlay welding in which a high frequency pulse arc is generated between a welding electrode and a base material to be welded, and a welding wire is fed during the high frequency pulse arc to perform welding. The arc length during welding is measured using a CCD camera image or a non-contact displacement meter to control the arc length to a predetermined value, and the arc voltage during welding is measured. Controlling the horizontal position or the lap position within the groove of the welding electrode based on the effective voltage, and controlling the welding position of the high-frequency pulse arc welding. apparatus. 4. A narrow gap welding or overlay welding in which a high-frequency pulse arc is generated between a welding electrode and a base material to be welded, and a welding wire is fed during the high-frequency pulse arc to perform welding. The horizontal position in the groove of the welding electrode or the lap position of overlay welding is controlled by the image of the CCD camera or the non-contact displacement meter, and the arc voltage during welding is measured. A high-frequency pulse arc characterized by calculating an arc average voltage and controlling a horizontal position in a groove of a welding electrode or a lap position of overlay welding based on the arc average voltage. Welding position control device for welding.