JPH0141439B2 - - Google Patents

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a vibration welding method in which vertical welding is performed while simultaneously giving rotation to a consumable electrode and vibration in the plate thickness direction of the base material when performing electrogas welding. The present invention relates to a rotating arc vertical welding method that involves motion, and particularly to a method of tracing the electrode position.

[Prior art]

In conventional electrogas welding, the groove is V-shaped, with a minimum gap of 10 mm and a groove angle of about 20 degrees, and the arc is constantly adjusted by the operator to aim near the center of gravity of the groove cross-sectional area, making it possible to perform the work without swinging. It is widely adopted. In this method, an arc is generated between the consumable electrode (wire) and the weld metal, and the base metal is melted in a high-temperature molten pool, so the applicable plate thickness range is about 12 to 30 mm, and for thick plates, the arc and the groove wall are Because of the distance, if the arc generation position deviates even slightly from the center of the groove, welding defects such as insufficient penetration are likely to occur. Therefore, there is a long-awaited welding method in which the arc is always adjusted to the correct position at the center of the groove, and which is less likely to cause welding defects such as insufficient penetration even on plates thicker than 30 mm, but none has been found yet.

A rotating arc welding method in which arc welding is performed while rotating a consumable electrode at a constant radius and speed is known, for example, in JP-A-55-133871 and JP-A-57-91877. .

Now, when such a conventional rotating arc welding method is applied to electrogas welding, when the thickness of the base material is thicker than a certain level, it is necessary to further swing the electrode in the thickness direction. In this case, if the position of the electrode nozzle is not adjusted correctly, not only will it not be possible to obtain good penetration and bead on the front and back sides, but in extreme cases, the electrode nozzle will come into contact with the copper butt, the groove wall, etc.

[Purpose of the invention]

The present invention employs a conventional rotating arc welding method and a swinging method in the plate thickness direction, so that the arc approaches the groove wall surface, so the above-mentioned insufficient penetration is unlikely to occur even in thick plates. This paper relates to a highly accurate groove tracing method. Therefore, an object of the present invention is to ensure that the position of the electrode nozzle is at an appropriate position within the groove when electrogas welding is performed while simultaneously giving rotation to the consumable electrode and swinging in the thickness direction of the base material. It is an object of the present invention to provide a rotating arc vertical welding method with oscillation that prevents the occurrence of penetration and defective bead shapes on the front and back sides as described above by automatically adjusting and welding so that the welding angle is the same.

[Summary of the invention]

In order to achieve the above object, the rotating arc welding method with oscillation according to the first invention of the present application is provided when electrogas welding is performed while giving an oscillation in the thickness direction of the base material plate at the same time as rotation to the electrode. , detect the waveform of the arc current or arc voltage of the electrode, divide the waveform into two equal parts in the plate thickness direction for each cycle of the rotation, and divide the waveform of each half cycle from the center of oscillation. A value S _F obtained by integrating the period of the first half of the swing cycle, and a value S _B obtained by integrating the waveform of each second half cycle from the center of the swing over the period of the second half of the swing cycle.
The method is characterized in that welding is performed while correcting the position of the center of oscillation in the plate thickness direction so that the difference value becomes equal to a preset reference value. The invention adds position control in the groove width direction in addition to the swing center scanning in the plate thickness direction according to the first invention, and the waveform detected as described above is applied to the groove width for each cycle of the rotation. Divide the left and right half cycles into two in the direction, compare the average value of the waveform for each left half cycle with the average value of the waveform for each right half cycle, and position it so that the difference value is zero. It is characterized by control.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic side view of an automatic vertical welding apparatus for carrying out the method of the present invention, and FIG. 2 is a plan view thereof. Further, FIG. 2 also shows the rotation locus of the consumable electrode at an arbitrary swing position. In these figures, 1 is a groove, 2 and 3 are base materials, 4 and 5 are fixed copper butts and sliding copper butts, and 6 is a consumable electrode, which has a predetermined rotation radius from the center A of the electrode nozzle 7. It is designed to be automatically fed to an eccentric position. Reference numeral 8 denotes a rotating device that vertically supports this electrode nozzle 7 in a rotatable manner, and is composed of a normal gear mechanism. The rotational position of the electrode nozzle 7 is detected by a rotational position detector 9 provided at the top thereof, and pulses are emitted at four points on the front, back, left, and right of rotation. Reference numeral 10 denotes a swinging device connected to the main body of the rotating device 8 via a swinging arm 11, and the base end of the swinging arm 11 is moved in the thickness direction of the base material at a predetermined period and amplitude by a W-axis motor 14. Performs a rocking action. Reference numeral 12 supports the swinging device 10 at its tip, and its base end is supported by an X-axis slider 13 that is slidable in the width direction of the groove.
15 is an X-axis motor for driving the X-axis slider 13. By these mechanisms, the deviation of the center position A of the electrode nozzle 7 can be corrected in the plate thickness direction and the groove width direction. Note that 16 corresponds to a cart that moves the entire welding device in the vertical direction.

Next, the method of the present invention will be explained together with the operation of the welding apparatus. As shown in FIGS. 1 and 2, the electrode nozzle 7 is vertically inserted into the groove 1, and while the electrode nozzle 7 is rotated by the rotating device 8, it is shaped into the groove 1 by the swinging device 10. It is swung in the thickness direction of the base material around a suitable position O (see Fig. 1). Since the consumable electrode 6 is automatically fed to an eccentric position with a predetermined rotation radius with respect to the electrode nozzle 7, the electrode 6 is rotated at a constant rate and at the same time is given swinging motion in the thickness direction of the base material. Electrogas welding can be performed.

In this case, the swing center position O is
It is set in advance at a predetermined position to match the shape of the groove 1. However, as welding progresses, if the center of oscillation shifts for some reason, it is necessary to correct the shift in the thickness direction of the base material and make it follow. That is, for example, the swing center position O is generally set at the center of the plate thickness, and if the swing center position O shifts to the left side (F side) in Fig. 2, insufficient penetration at the right end (B side) will occur. , this will lead to a defective back bead shape, and conversely, if it shifts to the right side (B side), there will be insufficient penetration at the left end (F side), leading to a defective front bead shape. Additionally, if the swing center position O shifts upward (R side) from the plate thickness center line, insufficient penetration of the groove wall on the lower side (L side) will occur, and conversely, if it shifts downward (L side), the upper This may result in insufficient penetration of the groove wall on the R side, resulting in poor bead shapes on both the front and back sides.

First, the following control of the swing center position of the present invention is performed as follows. That is,
While the electrode nozzle 7 is oscillating, the arc current or arc voltage of the rotating arc is detected, and its waveform is plotted against the center line a in the groove width direction for each period of rotation of the electrode 6 in FIG. 2 in the first half cycle and the second half cycle
The area S _F is obtained by integrating the waveform for each first half period of the rotation over the period of the first half period of the rotation from the center position O of the rotation. Find the area S _B by integrating over the period of the first half of the dynamic period. Then, the swing center position O is corrected to the correct position in the thickness direction of the base material so that the integral values S _F and S _B become equal.

Now, if accurate copying is being performed without any deviation in the position of the swing center position O in the thickness direction of the base material, the position between the arc rotation position C _f and the copper dowel 4 at the left side reversal position of the swing is correct. Since the distance and the distance between the arc rotation position C _r point at the right-side reversal position of the oscillation and the copper pad 5 are equal, the detected waveforms at both points are almost the same, and the integral value S _F of the first half period of rotation and the second half period are the same. The integral value S _B is also almost the same. However, if the swing center position O shifts to the left, the electrode 6 will move closer to the left copper butt 4 in the left inverted position, and will move further away from the right copper butt 5 in the right inverted position. A difference occurs between the above two distances. for example,
When detecting the arc current waveform, when the detected current waveform is at the left end of the swing (F side), the welding current value increases at the arc rotation position C _f point, and the integral value S _F is equal to the above normal case. increase compared to On the other hand, at the right end (B side) of the swing, the welding current value decreases at the arc rotation position C _r point, and the integral value S _B decreases compared to the above normal case. In other words, S _F > S _B.

Therefore, the swing center position is controlled to move so that S _F −S _B =0. At this time, the integral values S _F and S _B may be the maximum value or the average value of N values. Further, even if the swing center position shifts to the right side, contrary to the above, the position can be corrected in the same way. Further, similar control can be performed by using an arc voltage waveform instead of an arc current waveform.

This tracing control method will next be explained according to the embodiment shown in FIG. FIG. 3 is a control block diagram for oscillating tracing to correct deviations in the thickness direction of the base material. In the figure, 17 is a detector for the arc current or arc voltage waveform of the electrode 6, 18 is a reference value generator for extracting the pulsating flow component from the detected output waveform, and 1
9 is a differential amplifier for these detected waveforms and the reference value; 2
0 is the output waveform of the differential amplifier 19 in the first half (F
The rotational position of the electrode nozzle 7 is detected by the rotational position detector 9, and the rotational position signal is used to divide the electrode nozzle into two halves, the F side and the B side. Switched alternately to the side. Reference numeral 21 denotes an F-side integrator that integrates the waveform of each first half cycle of the rotation of the electrode 6 from the swing center position for the period of the first half cycle of the swing. This integral value _SF is input to the next differential amplifier 23. Reference numeral 22 denotes a B-side integrator which integrates the waveform for each second half cycle of the rotation of the electrode 6 from the swing center position over the period of the second half cycle of the swing. This integral value S _B is input to the differential amplifier 23 in the same manner as described above, where S _F and S _B are compared. The operation period of each of the F-side integrator 21 and the B-side integrator 22 is determined by a timing pulse generator 24 that generates pulses at the swing center and the left and right end positions. Reference numeral 25 denotes a differential amplifier, which outputs a differential amplification output of the integral values S _F and S _B , and a preset reference value 26 indicating the swing center position suitable for the groove shape. Compare.
27 controls the swing center position so that the differential output of the differential amplifier 25 becomes zero, and the W-axis motor 1
This is a drive controller that drives 4.

Therefore, if the control circuit shown in FIG. 3 is used, when the center of swing of the electrode nozzle 7 shifts, the difference between the integral values S _F and S _B obtained as described above will be used as the preset reference value. Since it is different from 26,
The W-axis motor 14 is driven via the W-axis driver 27 so that both are equal, and the swing center position of the electrode nozzle 7 is corrected in the thickness direction of the base material.
Since this operation is performed every half period of the swing, accurate swing tracing can be performed.

Next, the tracing control in the groove width direction of the present invention can be considered in the same manner as the above-described swing center position tracing control. In other words, in Fig. 2, if the swing axis coincides with the center line of groove 1, the distance between the arc rotation position C _R and the groove wall on the R side, and the distance between the arc rotation position C _L and the L side The distance between the groove walls is equal.

Therefore, the waveform detected as above is
Each period of rotation of the electrode 6 is divided into two equal parts, a right half period and a left half period, with respect to the center line b in the plate thickness direction, and the integral value S _R of each right half period and the integral value of each left half period are calculated. If S _L is determined and both integral values or average values are compared, the two values will be approximately equal. However, if the swing axis shifts upward (to the R side), the two distances will become different, and the welding current value will increase at point _C.
On the contrary, it decreases in _CL . Therefore, S _R > S _L. Therefore, the position of the swing axis is corrected so that S _R −S _L =0. Furthermore, the same procedure can be performed when the swing axis is shifted downward (L side).
In addition to the above-mentioned swing copying in the thickness direction of the base material, in order to correct the deviation in the groove width direction, as shown in Fig. 4,
This can be done by combining the control block diagram of FIG. 3 with a control book diagram for the groove width direction. In this case, since the electrode nozzle 7 does not swing in the groove width direction, the waveform of the detected arc current or arc voltage is divided into the left half period part (L side) and the right half period part (L side) in the groove width direction for each rotation period. Divide into half periods (R side), apply the average value 28 for each left half period and the average value 29 for each right half period to the differential amplifier 30, and adjust the X axis so that the difference value between the two becomes zero. The X-axis motor 15 may be driven via the driver 31. Thereby, the deviation in the center position of the electrode nozzle 7 is corrected not only in the base material plate thickness but also in the groove width direction, so that more accurate profile welding can be realized.
Note that in FIG. 4, the same reference numerals as in FIG. 3 indicate the same components, and a description thereof will be omitted.

〔Effect of the invention〕

As described above, according to the present invention, when electrogas welding is performed while rotating and simultaneously giving a swinging motion to the consumable electrode in the thickness direction of the base material, the shift in the swinging center position of the electrode nozzle can be corrected. Since it is possible to perform oscillation tracing at a position that is corrected every half period and is adapted to the groove shape, it is possible to perform good vertical welding without welding defects. Moreover, when the center of the electrode nozzle is traced not only in the plate thickness direction but also in the groove width direction, vertical welding can be performed more favorably.

[Brief explanation of drawings]

Fig. 1 is a schematic front view of an automatic vertical welding apparatus for carrying out the method of the present invention, Fig. 2 is a plan view of the same, and Fig.
The figure is a diagram of a control book used in the first invention of the present application.
FIG. 4 is a control book diagram similarly used in the second invention. 1: Bevel, 2, 3: Base material, 4, 5: Copper dowel,
6: Electrode, 7: Electrode nozzle, 8: Rotating device, 9:
Rotational position detector, 10: Swing device (W axis), 1
1: Swing arm, 12: Arm, 13: X-axis slider, 14: W-axis motor, 15: X-axis motor, 1
6: Trolley, 17: Arc current or arc voltage waveform detector, 18: Reference value generator, 19: Differential amplifier, 20: Changeover switch, 21: F side integrator, 2
2: B-side integrator, 23: Differential amplifier, 24: Timing pulse generator, 25: Differential amplifier, 26:
Reference value generator, 27: W-axis drive controller, 28: L
side average value, 29: R side average value, 30: differential amplifier, 31: X-axis driver.

Claims (1)

[Claims] 1. When electrogas welding is performed while rotating the consumable electrode and simultaneously giving it a swing in the thickness direction of the base material, detecting the waveform of the arc current or arc voltage, and converting the waveform to the waveform of the rotation The value S _F obtained by dividing each cycle into two equal parts in the thickness direction into the front and half cycles, and integrating the waveform of each half cycle from the center of oscillation over the period of the first half of the oscillation cycle, and the second half cycle of the rotation mentioned above. The value obtained by integrating the waveform for each period from the center of the oscillation over the period of the second half of the oscillation cycle.
A rotating arc with oscillation characterized by performing welding while correcting the position of the oscillation center in the plate thickness direction so that the difference between S and _B becomes equal to a preset reference value. Vertical welding method. 2. When electrogas welding is performed while rotating the consumable electrode and simultaneously giving it vibration in the thickness direction of the base material, the waveform of the arc current or arc voltage is detected, and the waveform is used to determine the thickness of the plate for each cycle of the rotation. The waveform of each half cycle is divided into two equal parts in the direction, and the waveform of each half cycle is integrated from the center of oscillation over the period of the first half cycle of oscillation, and the value S _F is obtained. Compare the value S _B obtained by integrating the period of the second half of the cycle from the center, correct the position of the above-mentioned rocking center in the plate thickness direction so that the difference value becomes equal to the preset reference value, and then Divide the detected waveform into two halves for each left and right half period in the groove width direction for each period of the rotation, and calculate the average value of the waveform for each left half period and the average value of the waveform for each right half period. A rotating arc vertical welding method involving oscillation, characterized in that welding is performed while correcting the position of the oscillation center in the groove width direction so that the difference value becomes zero.