JPH0259179A - Arc welding method - Google Patents

Abstract

PURPOSE:To allow copying control with high accuracy even if a groove shape is asymmetrical to the center line by using the time average value of the welding current or voltage of right and left groove faces as an object for comparison at the time of changing the set values of the oscillation width and oscillation position of a welding torch. CONSTITUTION:Automatic welding is executed by moving the welding torch which supports a consumable electrode in a weld line direction while oscillating the torch in a groove width direction. The oscillation pattern of the torch is set according to the groove shape of the welding joint part of this time. Circuits 13-15 for averaging the time value of the left surface, right surface and bottom determine the time average value of the current I by the signal of the welding current I detected by a detector and starts welding by setting the reference value of the oscillation width thereto. The circuits 13-15 output the voltage values VL, VR, VB corresponding to the time average value of the above-mentioned current I. The VL+VR and the reference value Vc1 are compared and V1 is determined in a circuit 24. The oscillation width is changed according to this value. The VL and VR are compared and VO is determined in a circuit 19. The set value of the oscillation position is changed according thereto.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses a consumable electrode (welding wire) that progresses welding along the weld line direction while swinging the welding torch in the groove width direction of the weld joint. In particular, the present invention relates to an arc welding method that uses the arc itself on the groove surfaces on both the left and right sides of a welded joint and causes its movement to follow the joint.

[Prior art] Conventionally, as this type of arc welding method, for example,
There is one disclosed in Publication No. 1-17590. In this technology, the welding torch is reciprocated in parallel in the direction of the groove width at a constant width in order to follow the welding line, and the welding current or welding voltage, including noise components, is integrated, respectively, during left and right half-cycle oscillations from the oscillation center. The swing center of the welding torch is controlled to move in the groove width direction so that the time average value of the detected value obtained by dividing the integral value by the swing time is equal on both the left and right sides.

When this technology is applied to arc welding of a welded joint where the angle of inclination of the groove surface is different on both the left and right sides of the weld line, the center of oscillation can be controlled by changing the oscillation center as a result of arc tracing because oscillation is performed within a fixed width. When done, the center of oscillation and the center of the groove (welding line position)
will no longer match.

Therefore, due to the parallel reciprocating movement, the groove center does not coincide with the swing center, resulting in a problem such as the wire protruding length becomes long, resulting in insufficient melt penetration. Therefore, in the past, the special public
A technique as shown in Japanese Patent No. 3462 has also been proposed. This technology detects the welding current as the welding torch oscillates, compares it with the current setting value at a predetermined wire protrusion length, and moves the welding torch up and down in the axial direction so that the difference becomes zero. In addition to controlling the wire protrusion length and chemotaxis,
When the welding torch reaches a set value of the height dimension from the weld line to the toe of the weld joint, the direction of swing is reversed and the swing itself follows the weld line.

[Problems to be Solved by the Invention] By the way, in the conventional arc welding method described above, control is instantaneously executed on the detected value in order to keep the wire protrusion length approximately constant with respect to the groove. A filter is used to remove noise from the values.

However, when such a method is used to perform high-speed oscillation during high-speed welding, a detection delay occurs in the filter, which impairs its control, and as a result, the reversal control of the oscillation force direction cannot be performed normally. This may cause problems such as the product disappearing.

Furthermore, a separate control means is required to determine the swing width, which poses the problem of complicated control.

The present invention has been made to solve the above-mentioned problems, and it is possible to achieve high-precision tracing control even if the groove shape is asymmetrical, and also to easily and accurately perform normal tracing even during high-speed welding. The purpose of the present invention is to provide an arc welding method that achieves the following.

[Means for Solving the Problems] In order to achieve the above object, the arc welding method of the present invention (I') presets the swing pattern of the welding torch according to the groove shape, and Welding is started after a reference value of the swing width is set in advance for the time average value of the welding current or welding voltage detected when the welding torch swings along the tip, and the left and right grooves are The welding current or welding voltage detected when the weld 1--chi swings along the left and right groove surfaces is detected respectively.

■After dividing the time integral value of the detected welding current or welding voltage by the swing time to obtain the time average value of the welding current or welding voltage for each of the left and right groove surfaces, Alternatively, the time average value of the welding voltage is added on both the left and right sides, and the added value is compared with the reference value of the oscillation width to determine the time average value reference difference. While changing and controlling the oscillation width membrane and fixed value, ■ Compare the time average values of the welding current or welding voltage obtained above on the left and right sides to find the difference between the left and right time average values, and ■ calculate the difference between the left and right time average values. The present invention is characterized in that the set value of the swing position of the welding torch is changed and controlled accordingly.

[Function] In the arc welding method of the present invention described above, when changing the oscillation width setting value and oscillation position setting value, the time average value of the welding current or welding voltage of the left and right groove surfaces is used as a comparison target. Unlike conventional methods that use time integral values, it is possible to match the center of oscillation with the center of the groove even if the groove shape is asymmetrical. is fixed and the fluctuation of the predetermined detected value due to high-speed swinging is taken in as a time average value as described above, so the conventional filter is unnecessary and all problems associated with the time delay of the filter are eliminated.

[Embodiments of the Invention] Hereinafter, an arc welding method as an embodiment of the present invention will be explained with reference to the drawings.

First, a schematic configuration of an arc welding apparatus to which the method of the present invention is applied will be explained with reference to FIG. In Fig. 2, 1 is the left and right groove surfaces on both sides of the weld line], a and lb are the base metal forming the weld joint IA inclined in the groove width direction, and 2 is the consumable electrode fed at a constant speed ( 3 is a welding torch that supports the wire 2 and sends it out toward the welding joint 1A;
4 is a rail laid approximately parallel to the weld joint IA, 5
6 is an oscillator provided on this truck 5 to drive the welding torch 3 up and down and swing it left and right; 8 is an oscillator that applies a welding voltage between the base material 1 and the welding torch 3; 9 is a welding current detector that detects the welding current; 10 is a control device that controls the oscillator 6 to drive and control the position and operation of the welding torch 3;
This control device 10 is constructed as shown in FIG. In the arc welding apparatus configured as described above, the welding torch 3 is moved in the welding line direction by driving the trolley 5 while being oscillated in the groove width direction by the oscillator 6.
Arc welding is performed along the weld joint IA.

Next, the detailed configuration of the control device 10 for carrying out the method of the present invention will be explained with reference to FIG. In Figure 3, 1
1 is an amplifier circuit that amplifies the welding current detection signal from the welding current detector 9; 12 is an amplifier circuit that blocks and removes noise components such as high frequency components that are included in the output from the amplifier circuit 11 and are caused by the commercial frequency of the welding power source 8; Low pass filter for 13
14 is a left side time averaging circuit, 14 is a right side time averaging circuit, and 15 is a bottom time averaging circuit.

The left surface time averaging circuit 13 receives the welding current detection signal that has passed through the low-pass filter 12.
The time-integrated value f''ILdt of the welding current at a is divided by the swing time TL to obtain the time average value of the welding current when the left groove surface swings, and the corresponding voltage value vL is output. The averaging circuit 14 receives the welding current detection signal I that has passed through the low-pass filter 12 and calculates the time-integrated value of the welding current on the right groove surface 1b by dividing /'IRdt by the swing time TR. The time average value of the welding current during surface swing is determined and the corresponding voltage value VR is output. moreover,
The bottom time averaging circuit 15 receives the welding current detection signal I that has passed through the low-pass filter 12 and calculates the time integral value 'a''ndt of the welding current at the bottom surface 1c of the weld joint IA (see FIG. 7(b)). is divided by the swing time TB to obtain the time average value of the welding current at the bottom of the groove and output the corresponding voltage value VB.

Here, the integration time, that is, the swing time TL+TR2'rB in each of the time averaging circuits 13 to 15 is set by command from the oscillation pattern command circuit 27, which will be described later. After the time average value is calculated according to the sampling command from the oscillation pattern command circuit 27, the voltage value V L +VR + VB corresponding to each time average value is calculated by the left side time average value holding circuit 16 and the right side time average value, respectively. Value holding circuit 17. It is designed to be stored and held in the bottom time average value holding circuit 18.

19 is a left side time average value holding circuit 16. Receive the voltage value VL + VR from the right side time average value holding circuit 17, compare these voltage values VL + VR, and calculate the time average value left and right difference Δv.
The comparator circuit 20 receives the voltage value VL+VR from the left side time average value holding circuit 1G and the right side time average value holding circuit 17, adds these voltage values VL+VR, and outputs the sum. A reference signal circuit 24 sets a predetermined reference value Vc to be obtained as described later; 24 compares the added value (VL+VR) from the adder circuit 20 and the reference value Vc from the reference signal circuit 23 to determine the time average value reference difference; Δ
This is a comparison circuit that calculates and outputs v1.

Furthermore, 25 is a predetermined reference value V obtained as described below.
Reference signal circuit 26 is a comparison circuit that compares the voltage value vB from the bottom time average value holding circuit 18 and the reference value Vez from the reference signal circuit 25 to obtain and output the time average value reference difference Δv2. be.

On the other hand, 27 is an oscillation pattern command circuit, and this oscillation pattern command circuit 27 is connected to the
The position in the axial direction (groove width direction) and the position in the Y-axis direction (groove depth direction) are set as a time function as an oscillation pattern, and the set positions X and Y are set as an X-axis position signal. and the X-axis amplitude adjustment circuit 2 as the Y-axis position signal, respectively.
8 and the Y-axis amplitude adjustment circuit 29, and at the same time, the left side time averaging circuit 13. While the welding torch 3 is moving along each part of the weld joint IA to the right time averaging circuit 14 and the bottom time averaging circuit 15, the welding current ■
This outputs a sampling command to command the integration period.

Also, the X-axis amplitude adjustment circuit 28. The Y-axis amplitude adjustment circuit 29 receives the X-axis position signal and Y-axis position signal from the oscillation pattern command circuit 27, respectively, amplifies and adjusts these signals to a predetermined width, and outputs the signals.The detailed configuration and operation are as follows. This will be explained later. Reference numeral 30 denotes an X-axis movement command circuit that receives the time average left-right difference Δv0 from the comparison circuit 19 and outputs a movement value of the position in the X-axis direction of the oscillation pattern corresponding to this left-right difference Δv0; 31 denotes this X-axis movement command circuit 30 32 is a time average value reference difference Δv2 from the comparison circuit 26.
a Y-axis movement command circuit that outputs a movement value of the Y-axis direction position of the oscillation pattern corresponding to the reference difference Δv2;
33 is an addition circuit that adds the movement value from the Y-axis movement command circuit 32 to the output value from the Y-axis amplitude adjustment circuit 29.

Furthermore, 34 is a comparison circuit, 35 is an X-axis driver, 36 is an X-axis motor, and 37 is an X-axis potentiometer.
The difference between the axis potentiometer 37 and the current position of the welding torch 3 in the X-axis direction is determined, and a command is sent to the X-axis driver 35 so that the difference becomes zero. Then, by driving and controlling the X-axis motor 36 by the X-axis driver 35,
Feedback control of the X-axis position of the welding torch 3 is performed. Similarly, regarding the Y-axis direction, the comparison circuit 38. Y-axis driver 39° Y-axis motor 40
．． A Y-axis potentiometer 41 is provided, and a comparison circuit 3
8 determines the difference between the position command value in the Y-axis direction from the adder circuit 38 and the current position of the welding torch 3 in the Y-axis direction from the Y-axis potentiometer 41, and controls the Y-axis driver so that the difference becomes zero. Send command to 39. By driving and controlling the Y-axis motor 40 by the Y-axis driver 39, feedback control of the Y-axis position of the welding torch 3 is performed.

By the way, the X-axis amplitude adjustment circuit 28 is configured as shown in FIG. 4, and includes a manual amplitude setter 28a, an addition circuit 28b, and a division circuit 28c. The adder circuit 28b adds the set value va set by the amplitude setter 28a and the time average value reference difference Δv1 from the comparator circuit 24, and outputs the result as V□ (=VI, +ΔV X ). Further, the division circuit 28c adds the position signal X from the oscillation pattern command circuit 27 to the addition circuit 28b.
is divided by the value v8 from , and output as V, (=X/V).

Here, the operation of this X-axis amplitude adjustment circuit 28 will be briefly explained with reference to FIG. 5.6. For example, points p, , p2 . as shown in FIG. 5(a). A groove-shaped welded joint having p, , )) 4 shall be welded. When swinging according to this groove shape from P machining → P2 → P, → P4, in this device, the position of each point in the X-axis direction is changed as shown in FIG. 5(b) and FIG. The voltage value is set by setting the dynamic center position to 0 potential, the left half side in the figure to one potential, and the right half side in the figure to 10 potentials. Then, the oscillation command circuit 27 outputs the
Axial position X□, X2. While inputting the voltage values corresponding to X, , X, to the X-axis amplitude adjustment circuit 28,
From a, the voltage value V adjusted according to the actual groove shape
. is input to the adder circuit 28b.

For these inputs, if the time average value reference difference ΔV□ from the comparison circuit 24 is O, the output value v2 from the division circuit 28C becomes as shown by the solid line in FIG. 6, and this output value v2 The welding torch 3 is oscillatedly driven by the X-axis motor 36 while performing feedback control at a set oscillation rate based on .

While welding is being performed in this manner, if the actual groove width during welding becomes smaller than the set oscillation width, the time average value reference difference ΔV from the comparator circuit 24 changes from 0 to a positive value. Change. This ΔV factor is calculated by the addition circuit 28.
At step b, the voltage value v from the amplitude setter 28a is added, and the output value v1 from the adding circuit 28b is . +Δv4. By inputting this value v1 into the division circuit 28c and dividing the X-axis position signal from the oscillation pattern command circuit 27 by ■□, the X-axis position of each point is changed and the corresponding voltage value ■2 is Output.

In other words, each point P□+ P 2 t P 3 j
The X-axis position of P4 is as shown by the dashed line in Fig. 6,
X1/vo.

From X2/V,, X, /V,, X4/VI, respectively, p%==x1/V, -p-'=xz/vo, p%
``x, /Vo, P4' = The oscillation width of the welding torch 3 is controlled by the shaft motor 36 as shown in FIG. 5(b).
It becomes smaller depending on the groove width.

In addition, contrary to the above explanation, when the groove width during welding becomes larger than the set oscillation width, the time average value reference difference ΔV from the comparison circuit 24 changes from 0 to a negative value. Therefore, the output value V from the adder circuit 28b becomes smaller than vo, the output value V2 from the divider circuit 28c becomes larger, and the oscillation width of the tvj contact torch 3 becomes larger.

In addition, the X-axis position signal from the oscillation pattern command circuit 27 was set to the maximum value at the left and right ends of each oscillation pattern.
Possible P2 on the control circuit. A minimum value between P and P may be set, and a multiplication circuit may be provided in place of the division circuit 28c.

Further, the Y-axis amplitude adjustment circuit 29 is also configured in substantially the same manner as the X-axis amplitude adjustment circuit 28 described above.

Next, an arc welding method carried out by the arc welding control device configured as described above will be explained with reference to FIG. 1 (flowchart).

First, depending on the groove shape of the weld joint IA, the welding torch 3
An oscillation pattern (oscillation pattern) is set in advance (step SL). The groove shape is shown in Fig. 7(a), (
There are various types as shown in b). The welded joint IA shown in Fig. 7(,) is during one-layer welding or the first layer of multi-layer welding, and the swing pattern is P□→P2
There are →PJ-+P2→P engineering, P□→P2→P, and →P engineering. The welded joint IA shown in FIG. 7(b) is when welding the second and subsequent layers of multilayer welding, and the swing pattern is as follows:
P□→P2→P2'→P3→p21→P2→P engineering and P□
→P2→P%→P, →P1. From these swing patterns, an appropriate one corresponding to the groove shape is set by the oscillation pattern command circuit 27.

Further, when the welding torch 3 swings along the groove surface of the weld joint IA in the set swing pattern, <~, 1. ．． d
t/TR, fλ'I B. dt/TB (the last reference value is set when the groove shape is as shown in Fig. 7(b)) is set (step S2).As for how to set this reference value, There are two methods: one is to use a part of the groove to set the reference value, and the other is to set the reference value by performing welding on a simulated groove of the applicable groove.

In the former method (2), after setting the swing pattern of the welding torch 3, the protruding length of the wire 2 from the welding torch 3 is cut to a predetermined length, and then the welding torch 3 is oscillated by the oscillator 6. , the tip of the wire 2 is on the groove surface 1 of the weld joint IA.
Welding is performed after manually adjusting the drive of the welding torch 3 so as to trace a, lb, and 1c to the extent that the desired excess thickness is obtained. In the case of the groove shown in Fig. 7(a), P□-
22 questions and P2-P, in the case of the groove shown in Fig. 7(b), P□-22, P2-P2' questions and p, '-p.
□Detects a welding current worker swinging between. Then, the detected current value is integrated, and the obtained integrated value is divided by the swing time TLI TRI TB (set by the oscillation pattern command circuit 27) of the detection section to obtain a time average value. Then, the time average value OIL for the left and right groove surfaces 1a and lb. dt/ T L and friend λ,,r R1dt/ T
R and the resulting value is set in the reference signal circuit 23 as the corresponding voltage value VCz. Further, a voltage value Vc2 corresponding to the time average value of 7% Be dt/T B for the bottom IC is set in the reference signal circuit 25.

In the latter method (2), a simulated groove that is the same as the groove to be actually welded is formed on a test plate, and the same procedure as in method (2) described above is performed on this simulated groove. Set the reference value. Incidentally, during actual welding, welding is naturally performed using the same swing pattern as the one used when obtaining the set reference value.

In this embodiment, the reference signal circuits 23 and 25 have a circuit configuration in which the base value can be set by voltage, and for example, a volume is provided for each applicable groove simply as a volume setting method. As a result, in each reference signal circuit 23.25,
A voltage value Vc (TVC2) corresponding to the reference value is set.

After setting the swing pattern and reference value as described above, arc welding is started (step S3). After the start of welding, while performing the welding operation, welding current I is detected by welding current detector 9 as welding torch 3 swings along left and right groove surfaces 1a, lb and bottom surface 1c of weld joint IA. S4), the detection signal is transmitted to the amplification circuit 11
The signal is amplified by the low-pass filter 12, and noise components are removed by the low-pass filter 12. At this time, in the case of the groove shape shown in FIG. 7(,), welding current IL between Pl-P2 and P2-P
While detecting IR, if the groove shape is as shown in Figure 7(b), between P knee P2 p2p21 question and P2
'-P, detect the welding current IL+ IR+ IB.

Then, the detected welding current rL+ IR+ re
are operated by the left time averaging circuit 13 . in accordance with the command from the oscillation pattern command circuit 27 . The input is input to the right side time averaging circuit 14 and the bottom time averaging circuit 15, and is time-integrated over each section in each circuit 13 to 15, and the time integral value is calculated as the swing time "L+TR".
+ Time average value of welding current/'ILdt/TL by dividing by TB.

Robust i, > I Rd t / T R * f:, I a
Calculate each of d t / Ta (step S5)
. The obtained time average values are stored in the right side time average value holding circuit 16. It is held in the left side time average value holding circuit 17 and the bottom time average value holding circuit 18. After a predetermined period of time has elapsed from the start of welding, the control device switches to the automatic tracing mode, and the above-mentioned time average value of the welding current I is obtained every half cycle of the oscillation rate, and is sent from the average value holding circuits 16 to 18 to the comparison circuit. 19. It is output to the adder circuit 20 and the comparator circuit 26.

Time average value ILdt for left and right groove surfaces 1a and lb
/TL and 橡, 1. dt/TR is inputted to the adder circuit 20 as a voltage value VL+VR corresponding to each position and added to obtain VL+vR. This added value vL+vR is input to the comparison circuit 24, and in this comparison circuit 24, the reference value Vct ((f, 'I
1. , dt/TL+ Sakura, I H, dt/ TFI)
voltage value corresponding to], and the time average value reference difference Δv
1 is calculated (step S6). This time average value reference difference ΔV□ is input to the X-axis amplitude adjustment circuit 28, and by the operation explained in FIGS. 4 to 6, the swing width setting value is changed according to the time average value reference difference Δv1, and the It is output as the value v2 (step S7). At this time, if the time average value reference difference ΔV□ is 0, no change control is performed;
If v1 is a negative value, the swing width is decreased as shown in Figure 8(a), while if Δv1 is a positive value, the swing width is decreased as shown in Figure 8(b). Enlarge.

In addition, the time average value I for the left and right groove surfaces 1a and lb
Ldt/TL, 4%, and I Rdt/TR are also input to the comparison circuit 19 as voltage values VL*VR corresponding to each position, and the time average value left-right difference vt, -vr<:Δv0 is determined (step S8) . This time average value left-right difference Δv0 is input to the X-axis movement command circuit 3o, and the time average value left-right difference Δv0 is input to the adding circuit 31 in order to change the swing position setting value according to the time average value left-right difference Δv0. A corresponding predetermined voltage value (movement value in the X-axis direction) is output and added to the voltage value v2 from the X-axis amplitude adjustment circuit 28 (step S9). At this time, if the time average value left-right difference Δv0 is O, no change control is performed, and if Δvo is a negative value, the swing position is moved to the left as shown in FIG. 9(a), while If ΔV0 is a positive value, the swing position is moved to the right as shown in FIG. 9(b).

If the swing pattern is as shown in FIG. 7(a), the point is P, = P2' (step 510).
, thereafter, steps 84 to S9 are repeated every half cycle of the oscillation. On the other hand, the swing pattern is shown in Figure 7 (b
), then P2≠P2' (step 510), so after performing steps S11 and S12, the process returns to step S4. That is, the time average values 'I Bdt/T B for the bottom IC are input to the comparison circuit 26 as the voltage value vB corresponding to this value, and in this comparison circuit 26, the reference value VC from the reference signal circuit 25 is inputted to the comparison circuit 26.
2(/?'I a, dt/TB), and the time average value reference difference ΔV2 is calculated by two times (step 511). This time average value reference difference Δv2 is determined by the Y-axis movement command circuit 3.
2, the swing position setting value in the groove depth direction is changed according to the time average value reference difference Δ■2, and a predetermined voltage value corresponding to the time average value reference difference Δv2 is input to the adding circuit 33. (movement value in the Y-axis direction) is output and added to the voltage value from the Y-axis amplitude adjustment circuit 29 (step 512). At this time, if the time average value reference difference Δv2 is 0, no change control is performed, and if Δ■2 is a negative value, the swing position is moved downward as shown in FIG. 10(a). , Δv2 are positive values, the swing position is moved upward as shown in FIG. 10(b).

Next, a specific example of the operation of the arc welding method performed as described above will be explained with reference to FIGS. 11 to 15. Each figure (a) shows the swing state of the welding torch 3 with respect to the weld joint IA, and each time (b) shows the welding current waveform obtained corresponding to the operation shown in each figure (a), which shows the welding The current waveform is obtained by passing the detected welding current through a low-pass filter and then measuring and recording it using an electromagnetic oscilloscope.

FIGS. 11(a) and 11(b) show the case where the welding torch 3 is oscillated with the oscillation pattern and the groove shape matching, and the welding torch 3 is R-4B1→B2→L→B2.
It swings in the order of →B□→R. At this time, the welding current value is always approximately constant, Δv0 = ΔV = Δv2 = 0, and arc welding is performed without changing the swing setting value.

FIGS. 12(a) and 12(b) show a case where the welding torch 3 swings with the oscillation pattern shifted to the right with respect to the groove, and at this time, /"I, dt/T+, < f
,"I,dt/TR, and Δv becomes a negative value.

Therefore, a command is output from the X-axis movement command circuit 30 to move the swing position to the left.

FIGS. 13(a) and 13(b) show a case where the welding torch 3 swings in a state where the swing width is small relative to the groove width, and at this time, ? ,'l2dt/Tt,+geI,dt/Tr
t< /, 7I 6dt/ T L + f: I, d
t/TR(=Vex) Tonari.

Δv1 becomes a negative value. Therefore, depending on this Δv0,
The X-axis amplitude adjustment circuit 28 outputs a command to widen the swing width setting value.

FIGS. 14(a) and 14(b) show a case where the welding torch 3 is oscillated with the oscillation center being shifted in the groove depth direction (in the direction of the bottom surface 1c of the groove). ,'I,dt/
Ta > /, 'I odt/ Ta (= Vcz), and Δv2 becomes a positive value. Therefore, a command is output from the Y-axis movement command circuit 32 to move the swing position upward.

In FIGS. 15(a) and 15(b), the welding torch 3 is RIB.

→B2→L-+R-) B work → B2 → L swings only in one direction in the groove width direction, and the oscillation pattern and the groove shape match. With this pattern, a large weld cross-sectional area can be obtained in one pass, and the number of passes can be reduced, but the welding current value during the period Tυ when the welding torch 3 moves from L4R is determined by the height of the weld metal, that is, the welding It changes in correlation with the speed, and is not constant even if the groove and oscillation pattern match. However, the time average value for the left and right groove surfaces 1a and lb is C
I 4dt/Tt, = f:RI 4dt/TR, and it can be seen that the groove shape and the oscillation pattern match with Δv, =O. As described above, in this embodiment, good tracing control can be performed even with an oscillation pattern in which welding oscillates in one direction as shown in FIGS. 15(a) and 15(b).

As described above, according to the arc welding method of this embodiment, unlike the conventional method using a time integral value, even if the groove shape of the weld joint IA is asymmetrical, the swing center and the groove center can be determined. This makes it possible to achieve high-precision tracing control. Furthermore, even if arc tracing is performed during high-speed welding, the swing pattern is fixed and the fluctuation of the predetermined detected value due to the high-speed swing is determined by the time average value of the welding current f" I sid t / T
Lr fo' I Rd t / TR1f''IBd
Since the data is captured as t/TB, there is no need for a conventional filter, and all problems associated with filter time delays can be eliminated.

In addition, although the above embodiment describes the case of an ideal state, in reality, because the wire 2 has a tendency to bend, etc., even when the groove center and the swing center coincide,
There may be a difference in the time integral value of the welding current I for the left and right groove surfaces 1a and lb. Therefore, in order to cancel this left-right deviation, a reference signal circuit that sets a predetermined offset value is provided on the output side of the comparison circuit 19, and a predetermined offset value from this reference signal circuit and ΔV from the comparison circuit 19 are connected. A comparison circuit that compares and outputs the difference to the X-axis amplitude adjustment circuit 28 may be provided. Here, to explain an example of how to set the predetermined offset value, before welding, match the swing pattern to the applicable groove, perform welding, and while checking the welding condition, visually check whether the swing pattern is open. The volume and the like constituting the reference signal circuit are adjusted so that Δvl becomes 0 when the shape matches the tip shape. Also, when the swing pattern shown in Fig. 15(a) is used, R-)B1 and B2→L
Which welding current value must be set separately, and at this time it is also necessary to set an offset, so a circuit as described above is provided.

Furthermore, in the above embodiment, the time average value of the welding current (■) is obtained for each half period or one period of the oscillation. However, in order to reduce the influence of disturbances such as noise, the average value of several times is calculated. You may also use it.

Furthermore, although the welding current is used in the above embodiment, the same effects as in the above embodiment can be obtained even if the time average value is determined using the welding voltage.

[Effects of the Invention] As detailed above, according to the arc welding method of the present invention, when changing the swing width setting value and the swing position setting value,
The time average value of the welding current or welding voltage for the left and right groove surfaces is used as a comparison target.

Even if the groove shape is asymmetrical, it is possible to match the center of oscillation with the center of the groove, achieving high-precision tracing control, and even in a small current range, a defect-free weld can be obtained, resulting in large welds in one pass. Since the amount of welding can be obtained, the number of passes is small, and defects that occur between buses can be significantly reduced, making it possible to realize high-quality automation of arc welding. Further, since the swing pattern is fixed and the fluctuations in the predetermined detected values due to high speed swing are taken in as a time average value, there is an effect that normal tracing can be performed easily and accurately even during high speed welding.

[Brief explanation of the drawing]

1 to 15 show an arc welding method as an embodiment of the present invention, with FIG. 1 being a flowchart, and FIG. FIG. 3 is a block diagram showing a control device for implementing this method, FIG. 4 is a block diagram showing the configuration of the X-axis amplitude adjustment circuit in this embodiment, and FIGS. 5(a) and (b)
and FIG. 6 are diagrams for explaining the operation of the X-axis amplitude adjustment circuit, FIGS. 7(a) and (b) are schematic diagrams for explaining the groove shape and the swing pattern, and FIG. Figure (a
), (b) are schematic diagrams for explaining the operation of changing the groove width setting value according to this embodiment, and FIGS. 9(a) and (b) are schematic diagrams for explaining the operation of changing the groove position setting value according to this embodiment. FIGS. 10(a) and 10(b) are schematic diagrams for explaining the operation of changing the set value in the groove depth direction according to this embodiment, and FIGS. 11 to 15 are schematic diagrams for explaining this embodiment. Each figure (a) is a schematic diagram showing the swing pattern of the welding torch relative to the groove, and each figure (b) corresponds to the operation shown in each figure (a). 2 is a graph showing a welding current waveform obtained by In the figure, 1 - base metal, IA... welded joint part, 1
a - left groove surface, lb - right groove surface, 1 c - bottom surface, 2
- Wire (consumable electrode), 3 - Welding torch, 4-9
-rail, 5...bogie, 6--oscillator, 8-...
Welding power source, 9.--Welding current detector, 10--Control device, 11.--Amplification circuit, 12.--Low pass filter,
13--Left surface time averaging circuit, 14.--Right surface time averaging circuit. 15...--Bottom time averaging circuit, 16--Left side time average value holding circuit, 17...-Right side time average value holding circuit,
18--Bottom time average value holding circuit, 19--Comparison circuit, 20--Addition circuit, 23--Reference signal circuit, 2
4... Comparison circuit, 25... Reference signal circuit, 26...
...Comparison circuit, 27.-Oscillation pattern command circuit,
28-X-axis amplitude adjustment circuit, 29-Y-axis amplitude adjustment circuit, 30--X-axis movement command circuit, 31-addition circuit, 32
...Y-axis movement command circuit, 33...-addition circuit, 34-
- Comparison circuit, 35 - X-axis driver, 36 - X-axis motor, 37 - X-axis potentiometer, 38 - Comparison circuit, 39 - Y-axis driver, 40 - Y-axis motor, 41
...-Y-axis potentiometer. Patent applicant: Kobe Steel, Ltd.

Claims (1)

[Claims] In an arc welding method in which a welding torch supporting a consumable electrode is moved in the welding line direction while swinging in the groove width direction to automatically perform welding along the welding line, The swing pattern of the welding torch is set in advance, and the swing width relative to the time average value of the welding current or welding voltage detected when the welding torch swings along the left and right groove surfaces of the welding joint. After setting a reference value in advance, welding is started, and the welding current or welding voltage detected when the welding torch swings along the left and right groove surfaces of the weld joint is applied to the left and right groove surfaces. After detecting each of the above, and dividing the time integral value of the detected welding current or welding voltage by the swing time to obtain the time average value of the welding current or welding voltage for each of the left and right groove surfaces,
The obtained time average value of welding current or welding voltage is added to the left and right sides, and the added value is compared with the reference value of the oscillation width to determine the time average value reference difference, and according to the time average value reference difference. While changing and controlling the swing width setting value of the welding torch, comparing the obtained time average values of the welding current or welding voltage between the left and right sides to determine a difference between the left and right time average values,
An arc welding method characterized in that a set value of the swinging position of the welding torch is changed and controlled in accordance with a difference between left and right time average values.