JPH0947871A - Oscillating high speed rotation arc welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form left/right symmetrical weld bead as well as to execute groove copying in high precision by welding with reversing the rotating direction of arc for right half period and left half period of oscillation, detecting the wave form of arc voltage and correcting the position of oscillation. SOLUTION: A groove 3 of objects 1, 2 to be welded are subjected to oscillating high speed rotation arc welding. A center 9 of rotating arc is oscillated so as to take the locus of straight line part A→B→C→D→E→F→A in the groove 3. A rotating direction of arc is clockwise for a straight line part A→B section at the right side R of groove 3 and counterclockwise for a straight line part D→E section at the left side L. The advancing directions of arc at a right side groove wall face 7 and left side groove wall face 8 are same for the welding advancing direction, the weld beads are turned to left/right symmetry. By detecting the wave form of arc voltage or welding current and integrating for right/left it respectively, in the case a difference of the integrated values exceeds the reference value, the oscillating position is corrected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oscillating high-speed rotary arc welding method in which a welding torch is oscillated in a groove width direction while rotating an arc at a high speed to perform welding.

[0002]

2. Description of the Related Art A high-speed rotating arc welding method is a method of welding while rotating an arc at a high speed at a predetermined radius.
Since the arc is dispersed, the welding amount can be increased with a large current. As a result, it is a highly efficient welding method capable of significantly improving the welding speed as compared with the conventional welding method by weaving.

However, when the groove width becomes larger than the upper limit of the radius of gyration of the arc due to the structure of the work to be welded, restrictions on the groove processing, etc., sufficient penetration in the groove wall is obtained. There is a problem that you can not do.

As a method of coping with such a large groove width, there is a method described in Japanese Patent Publication No. 1-39874. The method involves oscillating an arc rotating at a high speed in the same direction in the groove width direction at a constant cycle and amplitude, detecting a waveform of arc voltage or welding current, and rotating the waveform with respect to the welding advancing direction. The left half cycle and the right half cycle are divided into the left half cycle and the area of the left split waveform of the rotation for the left half cycle of the oscillation with respect to the groove center, and the right side of the rotation for the right half cycle of the oscillation. In this method, the areas of the divided waveforms are integrated, the integrated values are compared, and welding is performed while correcting the center position of the swing so that the difference becomes zero. In other words, by rotating the arc at a high speed and swinging the welding torch with a predetermined amplitude around the center of the groove width as the center of the swing, even if the groove width is wide, the high-speed rotating arc is generated over the entire groove width. The welding method can be applied.

[0005]

Normally, when the arc is rotated at a high speed in the same direction, the directions of the arcs contacting the groove wall surface on the right side and the groove wall surface on the left side in the welding advancing direction are different from each other. Therefore, there is a difference in the influence of the rotation of the arc on the behavior of the molten metal, and there is an inherent risk that the weld bead surface shape and the penetration shape become asymmetrical in the groove width direction.

FIG. 6 is a cross-sectional view showing a phenomenon in which the welding beads are asymmetrically biased to the left and right, 1 and 2 are materials to be welded, 3 is a groove, 4 is a backing material, and 5 is asymmetrical as described above. Unbalanced weld beads. When welding is performed by rotating the arc in the right rotation, a weld bead having a shape that is raised on the left side and pushed down on the right side in the welding progress direction is formed.

In the method disclosed in Japanese Patent Publication No. 1-39874, the arc is rotated in the same direction at a high speed and is swung in the groove width direction. The difference in the influence on the behavior of the metal becomes remarkable, and the above-mentioned weld beads tend to be asymmetrical in the groove width direction.

When such an uneven bead is formed,
The problem that fusion failure easily occurs at the right groove bottom in FIG. 6 and the groove bottom is asymmetric in laminated welding, so the arc voltage or welding current waveform is not symmetrical. There is a problem that the groove tracking by the arc sensor is not performed well.

The present invention has been made in order to solve the above-mentioned problems, and provides an oscillating high-speed rotary arc welding method capable of forming excellent welding beads even when the groove width is wide. is there.

[0010]

[Means for Solving the Problems]
The first means is welding toe while rotating the arc at high speed.
When the welding is performed by swinging the jaws in the groove width direction,
Reverse the arc rotation direction in the right half cycle and the left half cycle
The arc voltage or welding current
The shape is detected and the waveform is rotated in the predetermined section of the right half cycle of the oscillation.
Integrates within a specified range of left half period and right half period
And the difference ΔS between the integrated values (SL) R and (SR) R_RTo
The difference ΔS between the integrated values_RIs the preset standard
If it is larger than the value, set the right end position in the next swing.
Corrected inward, the difference ΔS of the integrated values _RIs preset
If it is smaller than the reference value, the right end of the next swing
The position of the outside of the
The right half cycle and the left half cycle of rotating the waveform in a fixed section
Each is integrated in a fixed range, and the integrated values (SR) L and (S
L) Difference from L ΔS_LAnd the difference ΔS of the integrated values_LGaara
If it is larger than the set reference value, the next swing
The position of the left end in is corrected to the inside, and the difference ΔS of the integrated values is
_LIf is smaller than the preset reference value, then
It is special to correct the position of the left end of the swinging motion to the outside.
This is a characteristic of the swing high-speed rotary arc welding method.

The second means detects the variation amount of the groove width by correcting the right end position and the left end position of the swing in the swing high-speed rotary arc welding method of the above-mentioned first means, It is an oscillating high-speed rotary arc welding method characterized by controlling welding conditions so as to maintain a constant bead height even if there is a variation in groove width.

In the first aspect of the present invention, since the rotation directions in the right half cycle and the left half cycle of the oscillation are opposite, the arc wall contacting with the groove wall surface on the right side and the wall surface on the left side in the welding proceeding direction respectively. Both are in the same direction as the advancing direction, or both are in the opposite direction to the welding advancing direction. As a result, the influence of the rotation of the arc on the behavior of the weld metal does not differ between the left and right of the welding advancing direction, so that the weld bead surface shape → the welded shape is symmetrical in the groove width direction.

When the welding torch approaches the groove wall surface, the arc length on the groove wall surface side becomes shorter and the arc voltage and the welding current decrease, so that the integrated values of the groove center side of the arc rotation and the groove wall surface side are obtained. There is a difference. If the difference is larger than the reference value, it means that the welding torch is too close to the groove wall surface, so in the next swing, the swing reversal position is corrected to the groove center direction, and the difference Is smaller than the reference value, it means that the welding torch is too far away from the groove wall surface.Therefore, in the next swing, by correcting the swing reversal position toward the groove wall surface, Even if there is a change in the groove width or a bend in the groove line due to the processing accuracy, welding heat influence, etc., it is possible to perform automatic groove tracing.

Even if the groove width changes, the welding bead height can be made constant by detecting the amount of change and adjusting the welding conditions.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view for explaining an embodiment of a swing high-speed rotary arc welding method according to the present invention.
(A) is a plan view and (B) is a groove cross-sectional view.

In FIG. 1, 1 and 2 are materials to be welded, 3 is a groove formed from the materials to be welded 1, 2 and groove walls 1a, 2
a.

Reference numeral 6 is a center line of the groove 3. Reference numerals 7 and 8 are wall edge lines of the groove 3. Reference numeral 9 is the locus of the center of rotation of the high-speed rotating arc swinging in the groove 3, and also the locus of the welding torch.

In the embodiment of the present invention, the center of the rotating arc oscillates in the groove 3 so as to form a locus of a straight line portion A → B → C → D → E → F → A. The rotating direction of the arc rotating at a high speed is clockwise (CW) in the A → B section on the right side (R) of the groove 3 and counterclockwise in the D → E section on the left side (L) of the groove 3. Turn around (CCW) (direction of arrow).

Contrary to the above, the arc may be rotated counterclockwise in the right (R) section and clockwise in the left (L) section. In short, the left wall surface 1a of the groove 1a, It suffices that the arc rotation direction is symmetrical with respect to the groove right wall surface 2a on the left and right sides of the swing.

FIG. 2 is a cross-sectional view of the weld bead W obtained by the embodiment of the present invention, in which a symmetrical weld bead is obtained.

FIG. 3 shows the trajectory of the welding torch, the arc rotation speed change, and the arc voltage (arc current) integration interval in the embodiment of the present invention. here,
The horizontal axis represents the change over time, represents the position in the welding advancing direction, and the swing positions A to F are entered.

FIG. 3A shows the locus of the arc rotation center (welding torch). The vertical axis represents the movement amount of the welding torch, the right side movement amount is shown at the top and the left side movement amount is shown at the bottom. As an example, the swing pattern has a swing width of 3 mm, and the swing of the welding torch is stopped for a predetermined time at both ends of the swing (A → B, D → E).

FIG. 3B is a timing chart of changes in the rotation speed of the arc. The vertical axis represents the number of revolutions of the arc. The upper part represents the right rotation and the lower part represents the left rotation. The arc rotation direction is reversed near the groove centers C and F, and the arc rotation speed is 50H on the left and right groove walls A → B and D → E.
z is constant.

FIG. 3C shows a section where the arc voltage or the welding current is integrated, and the hatched portion is the integration section. In the right half cycle of the swing, the integration is performed in a predetermined section between A and B, and in the left half cycle of the swing, the integration is performed in a predetermined section between D and E.

FIG. 4 is a diagram showing an integral section and an integral range of the rotary arc arc voltage or welding current.

FIG. 4A is a schematic plan view of the groove,
In the predetermined section between A and B where the rotating arc approaches the groove 8 on the right side wall of the groove, the arc voltage is integrated in a predetermined range on the left side and a predetermined range on the right side of the rotation of the arc shown by hatching in FIG. The integrated value (SL) R and the integrated value (SR) R
The difference ΔS _R with Similarly, in a predetermined section between D and E in which the rotating arc approaches the groove left side wall edge line 7, FIG.
The arc voltages are respectively integrated in a predetermined range on the right side and a predetermined range on the left side of the arc rotation indicated by hatching, and a difference ΔS _L between the integrated value (SR) L and the integrated value (SL) L is obtained. Note that C _f indicates the center of the front part of the rotating arc, and C _r indicates the center of the rear part of the rotating arc. L indicates the left part and R indicates the right part. The integration range is defined in any range from 5 ° to 180 °.

Then, the differences ΔS _R and Δ between the above integrated values
By comparing S _L with the reference value, respectively, the welding torches 1 on the left and right will be set so as to move toward the groove center when the difference is large, and toward the groove wall when the difference is small.
If the swing center of No. 1 is corrected, the welding groove of the welding torch 11 can be automatically traced, and the swing width can be appropriately adjusted with respect to the variation of the groove width.

Further, since the variation amount of the groove width can be detected,
By adjusting the welding conditions so as to correspond to changes in the welding cross-sectional area, the weld bead height can be kept constant even if the groove width changes.

The groove fluctuation width Δw is equal to the fluctuation width fluctuation ΔG, and Δw = W−Wo = ΔG. W:
Detected groove width, Wo: Standard groove width Therefore, the amount of change ΔSD of the welding cross-sectional area is ΔSD = Δw × Ho = ΔG × Ho when the welding bead height is Ho.

FIG. 5 is a control circuit diagram in the above-described embodiment of the present invention. In FIG. 5, 1 and 2 are materials to be welded, 3
Is a groove, 4 is a backing material, and 10 is a welding power source. A power supply circuit from the welding power source 10 to the welding torch 11 and the material 2 to be welded is formed by the power cable 10a and the ground cable 10b. In addition, 11 'is a welding wire, 1
2 is an arc.

Reference numeral 13 is a rotary motor for imparting a high speed rotation to the arc 12, and a high speed rotation of the arc is obtained by eccentrically rotating the welding torch 11 and the like at a high speed via the rotary drive unit 14.

Reference numeral 15 is an arc rotational position detector, for which an encoder or the like is used. 16 is an X-axis motor for driving the welding torch 11 in the groove width direction (X-axis).
The position in the groove width direction is detected by the X-axis position detector 17 as the X-axis movement amount (Xp).

Reference numeral 18 denotes an X-axis feed mechanism, which is an X-axis motor 1
6 includes a screw shaft 18a and an arm 19 screwed to the screw shaft 18a. The above mechanism is mounted on a welding carriage (not shown).

When the welding wire 11 'of the welding torch 11 is energized by the welding power source 10 to generate an arc and the swing high-speed rotary arc welding is started by the X-axis motor 16 and the rotary motor 13, the arc voltage detector 20 causes Regarding the arc voltage between the welding torch 11 and the base metal, the value (Xp) of the arc rotation position timing from the arc rotation position detector 23 and the arc rotation center position (position of the welding torch 11) in the groove width direction is the X axis. At the timing of output from the position detector 24, it is taken into the swing right half-cycle integrator 21 and the swing left half-cycle integrator 22, and the left and right half-cycles (SR) R and (S) are taken.
L) R and (SL) L and (SR) L are obtained.

Further, the X-axis swing control circuit 25 is given a swing start and stop command and a swing pattern command (swing speed, swing width, both ends of groove groove stop time).

The arc voltage waveform values fetched by the oscillating right half-cycle integrator 21 and the oscillating left half-cycle integrator 22 are:
First, the integrated value (S
R) R and the left integrated value (SL) R are output separately.

Similarly, the left integrated value (SL) L and the right integrated value (SR) L of the arc rotation in the left half cycle are separately output.

The integrated values on the left and right sides of the arc rotation in the left and right half cycles are (SL) R- (S
R) R = ΔS _R and (SR) L− (SL) L = ΔS _L
Get.

The left and right difference integral values ΔS _R and ΔS _L are
The left and right end setting calculators 28 and 29 compare with the reference value from the reference value setter 30, and if ΔS _R in the right half cycle is larger than the reference value, move the right end position of the swing to the inside,
If it is small, it is controlled by the X-axis motor 16 via the command of the X-axis swing control circuit 25 and the X-axis drive circuit 31 in order to correct it in the next swing. A similar correction is made to ΔS _L in the left half cycle.

A command from the X-axis swing control circuit 25 controls the torch rotation control circuit 32 and the torch rotation drive circuit 33 to give a reverse rotation command to the arc rotation motor 13. Since the X-axis swing control circuit 25 also controls the swing speed of the welding torch 11, it is instructed to the X-axis drive circuit 28 as a speed command.

As a method for keeping the weld bead height constant, a welding condition reference setting circuit 34 is provided, and the reference swing width from the welding condition reference setting circuit 34 and the X-axis swing control circuit 25 are used. The X-axis swing width is subtracted by the subtracter 35, and the swing width change amount ΔG is output. The swing width change amount ΔG is multiplied by the reference welding bead height Ho in the welding condition adaptive control calculation circuit 36 to calculate the change amount ΔSD of the welding cross-sectional area. The amount of change ΔSD is compared with the value of the reference welding speed, and the welding control device 37 is instructed to obtain a welding speed corresponding to the amount of change ΔSD of the welding cross-sectional area. As the control of the welding speed, for example, the speed of the welding carriage (not shown) is controlled to be slow if the gap is large and fast if the gap is narrower than the standard.

Further, as a method of controlling the height of the welding bead with respect to the variation of the groove width, a method of using the welding speed control and the welding current control together, a welding current control and a welding wire feeding control with the welding speed kept constant. It is also possible to use a combination method.

Although the case where the arc voltage is used has been described above, the same effect can be obtained by using the welding current.

[0044]

When swinging by the high-speed rotating arc welding method, the directions of the arcs with respect to the groove wall are unified by reversing the rotating directions of the arcs on the left and right sides of the groove. Beads are formed. Then, the groove tracing can be automatically performed with high accuracy by the left-right comparison method of the integrated value of the arc voltage.

Further, since the welding condition is controlled by detecting the change in groove width, it is possible to always carry out welding with the welding bead having a constant height even if the groove width changes.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating an embodiment of a swing high-speed rotary arc welding method of the present invention.

FIG. 2 is a sectional view of a welding bead according to an embodiment of the present invention.

FIG. 3 is a diagram showing a locus of a welding torch, an arc rotation speed, and an integration section of an arc voltage (welding current) in an example of the present invention.

FIG. 4 is a diagram showing an arc voltage integration section and an integration range in an example of the present invention.

FIG. 5 is a control circuit diagram in the embodiment of the present invention.

FIG. 6 shows a weld bead formed according to the prior art.

[Explanation of symbols]

 1 welded material 2 welded material 3 groove 4 backing material 5 uneven welding bead 6 groove center 7 groove right side 8 groove left side 9 swing locus 10 welding power supply 11 welding torch 12 arc 13 rotary motor 14 rotation drive unit 15 arc rotation position detector 16 X-axis motor 17 X-axis position detector 18 X-axis feed mechanism 19 arm 20 arc voltage detector 21 swing right half-cycle integrator 22 swing left half-cycle integrator 23 arc rotation position detector 24 X-axis position detector 25 X-axis swing control circuit 26 Subtractor 27 Subtractor 28 Left end setting calculator 29 Right end setting calculator 30 Reference device setter 31 X-axis drive circuit 32 Torch rotation control circuit 33 Torch rotation drive circuit 34 Welding condition standard setting circuit 35 Subtractor 36 Welding condition adaptive control arithmetic circuit 37 Welding control circuit

Claims (2)

[Claims] 1. When performing welding by swinging the welding torch in the groove width direction while rotating the arc at high speed, the welding is performed by reversing the rotating direction of the arc in the right half cycle and the left half cycle of the swing. While performing the arc voltage or the waveform of the welding current is detected, the waveform is integrated in the predetermined range of the left half cycle and the right half cycle of the rotation in the predetermined section of the right half cycle of the oscillation,
The difference [Delta] S _R between the integrated value (SL) R and (SR) R determined, the position of the right end on the inner side in the difference [Delta] S _R is large if the next than the predetermined reference value oscillation of the integrating value If the difference ΔS _R between the integrated values is smaller than the preset reference value, the position of the right end of the next swing is corrected to the outside and the waveform is rotated in a predetermined section of the left half cycle of the swing. Of the right half-cycle and the left half-cycle of each, and the integrated values (SR) L and (S
L) The difference ΔS _L with _L is calculated, and when the difference ΔS _L of the integrated values is larger than a preset reference value, the position of the left end in the next swing is corrected to the inside, and the difference ΔS _L of the integrated values is corrected.
_{When L} is smaller than a preset reference value, the swing high-speed rotary arc welding method is characterized in that the position of the left end in the next swing is corrected to the outside. 2. The swing high-speed rotary arc welding method according to claim 1, wherein the variation amount of the groove width is detected by correcting the right end position and the left end position of the swing to keep the welding bead height constant. A swing high-speed rotation arc welding method, characterized in that welding conditions are controlled in accordance with the amount of fluctuation.