JP2003053532A - Tandem arc welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a tandem welding method which is capable of efficiently obtaining a sound weld zone free of welding defects over the entire length of the weld line of a work in welding the work in which interference members exist at the beginning end and termination of the weld line. SOLUTION: A torch is made to travel back and forth at the beginning end of the weld line and single arc welding is performed by a succeeding electrode under prescribed welding condition in accordance with the previously instructed beginning end treatment welding start point P1, weld line start point Ps and tandem weld line start point P2. The torch is made to travel from the tandem weld line start point P2 to the tandem weld line end point P3 and the tandem arc welding by the preceding and following electrodes is performed and thereafter the torch is made to travel back and forth at the termination of the weld line in accordance with the previously instructed tandem weld line end point P3, weld line end point Pe and termination treatment welding end point P4 in succession thereto and the single arc welding by the preceding electrode is performed under the prescribed welding condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tandem arc welding method for performing tandem arc welding by a gas shield welding method, and more specifically, to a starting end portion and an end portion of a welding line by using a teaching regenerative welding robot. When welding a workpiece with an interference member, perform single arc welding in which the torch travels back and forth only at the start and end of the welding line,
By performing tandem arc welding in which the torch travels from the starting point side of the welding line to the ending point side in the welding line portion excluding the start and end portions, a sound weld portion without welding defects can be efficiently obtained over the entire welding line length of the workpiece. The present invention relates to a tandem arc welding method capable of performing the above.

[0002]

2. Description of the Related Art In the field of steel plate welding such as construction machinery manufacturers and bridge manufacturers, there is a strong demand for welding technology with higher efficiency than before in order to further reduce costs. The tandem arc welding method is a welding technique to meet such a demand, and arranges a leading electrode and a trailing electrode, which use a welding wire as a consumable electrode, with a predetermined electrode distance in the welding line direction of a work. Then, welding is performed by generating a gas shield arc from each electrode. This tandem arc welding method has a significantly large amount of wire melting as compared with arc welding using a single electrode, and enables highly efficient welding. In the tandem arc welding method, the distance between the leading electrode and the trailing electrode is made close to each other and two arcs generated respectively form one molten pool to perform welding, and the distance between the electrodes is sufficiently separated. There is a method of independently forming a molten pool by each arc and welding. The former tandem arc welding method is adopted for a work composed of a relatively short welding line, and the tandem arc welding method targeted by the present invention is the former one.

[0003]

However, in a construction machine maker or the like for welding thick steel plates, a two-electrode integrated torch or two single-electrode torches are mounted on a teaching regenerative welding robot to perform tandem arc welding. In such a case, as shown in FIG. 4 as an example, for a workpiece having interference members (side plates) S1 and S2 at the start end and the end of the welding line WL, the interference member S1 interferes with the starting end of the welding line. Therefore, the leading electrode cannot be located at the welding line starting point Ps, so that tandem arc welding cannot be performed at the portion corresponding to the distance between the electrodes from the welding line starting point Ps, and the interference member S2 becomes an obstacle at the welding line terminal portion. The trailing electrode to the welding line end point Pe
Therefore, tandem arc welding cannot be performed in the portion corresponding to the distance between the electrodes from the welding line end point Pe. For this reason, since it is necessary to rework the portion where this tandem arc welding cannot be performed, the application of tandem arc welding may be postponed to a work in which the interference members S1 and S2 exist at the start and end of the welding line WL. There were many.

The present invention has been made under such circumstances, and an object of the present invention is to weld a workpiece having an interference member at the start end and the end of the welding line by using a teaching regenerative welding robot. In doing so, tandem arc welding is performed in which the torch is made to travel back and forth only at the start and end portions of the welding line, and the torch is run from the welding line starting point side toward the ending point side at the welding line portion excluding the starting and ending portions. By performing the above, it is possible to provide a tandem arc welding method capable of efficiently obtaining a sound weld portion having no welding defects over the entire welding line of the work.

[0005]

In order to achieve the above-mentioned object, the invention of claim 1 provides a teaching reproduction welding robot.
An electrode-integrated torch or two single-electrode torches are mounted, and a leading electrode and a trailing electrode, which use the welding wire as a consumable electrode, are arranged with a predetermined electrode distance in the welding line direction of the work, and a gas shield is provided. When performing tandem arc welding by the welding method, with respect to the welding line of the workpiece, the welding line starting point and the welding line ending point are taught in advance, and the position apart from the welding line starting point by a predetermined length on the welding line ending point side. The starting point welding start point and tandem welding start point are taught in
A tandem welding end point and a termination processing welding end point are taught at positions separated by a predetermined length on the welding line starting point side from the welding line end point, and a trailing electrode is positioned at the starting end processing welding start point, Torch travel is started by generating an arc only in the trailing electrode, then the torch angle of the trailing electrode is changed to the forward angle, and when the trailing electrode reaches the welding line starting point, the torch traveling is temporarily performed. After that, the torch traveling direction is reversed, the torch angle of the trailing electrode is returned to the torch angle during tandem welding, and when the leading electrode reaches the tandem welding start point, an arc is generated in the leading electrode to cause tandem welding. When welding is started and tandem welding proceeds and the trailing electrode reaches the tandem welding end point, the arc of the trailing electrode is stopped, and then the torch angle of the leading electrode is set to the forward angle. Change so that suspends the torch travel this leading electrode reaches the weld line end point,
Thereafter, the torch traveling direction is reversed, the torch angle of the leading electrode is returned to the torch angle during tandem welding, and when the leading electrode reaches the termination processing welding end point, the torch traveling is stopped and the crater processing condition is used for a predetermined time. The tandem arc welding method is characterized in that the arc of the preceding electrode is stopped after the crater treatment is performed to end the welding operation.

According to a second aspect of the present invention, in the tandem arc welding method according to the first aspect, the starting point treatment welding start point and the tandem welding start point are separated from the welding line start point by 20 to 60 mm on the welding line end point side. The position of the range is set, the torch angle of the trailing electrode at the starting point of the welding line is set to an advance angle in the range of 2 to 45 °, and the torch running temporary stop time at the starting point of the welding line is set. Is set in the range of 0.3 to 3.0 seconds, and the tandem welding end point and the termination treatment welding end point are 2 on the welding line start point side from the welding line end point.
Be set to a position in the range 0 to 60 mm apart,
The torch angle of the leading electrode at the end of the welding line is 2
Is set to an advance angle in the range of up to 45 °, and the torch travel suspension time at the welding line start point is 0.3.
To 3.0 seconds and the crater processing time is set to 0.2 to 5.0 seconds.

The tandem arc welding method according to the present invention comprises:
When welding a workpiece with an interference member at the start and end of the welding line using the teaching regenerative welding robot, single arc welding is performed in which the torch travels back and forth only at the start and end of the welding line. Tandem arc welding in which the torch travels from the welding line starting point side toward the ending point side is performed in the welding line portion excluding the start and end portions. In the tandem arc welding method according to the present invention,
A welding wire having a wire diameter of 1.2 mmφ, which is most frequently used, is used for both the leading electrode and the trailing electrode.

FIG. 1 is a view for explaining a tandem arc welding method according to the present invention and is a diagram showing teaching points Ps, Pe, P1 to P4 on a welding line. As shown in the figure, a welding line starting point Ps and a welding line ending point Pe are taught in advance for the welding line of the work having the interference member on the starting end side and the ending end side of the welding line, and both of them are taught. A start-end treatment welding start point P1 and a tandem welding start point P2 are taught at a position distant from the welding line start point Ps by a predetermined length on the straight welding line, and tandem welding is completed at a position distant from the welding line end point Pe by a predetermined length. A point P3 and a termination welding end point P4 are taught.

[0009] First, at the start point treatment welding start point P1 → the welding line start point Ps → the tandem welding start point P2, the start end treatment welding in which the weld bead is formed by the single arc welding using only the trailing electrode is performed.

Here, the start point treatment welding start point P1 and the tandem welding start point P2 on the welding line are the welding line start point Ps.
It may be set at a position in the range 20 to 60 mm away from the welding line end point Pe side. Note that the tandem welding start point P2 at which an arc is also generated in the preceding electrode is set apart from the welding line start point Ps by a length of (interelectrode distance) + (predetermined distance). The inter-electrode distance between the leading electrode and the trailing electrode is, for example, 15 mm. The P1 on the welding line
The point and the point P2 may be set at different positions, but they are at the same position (coordinate position) from the point that the welding bead height (welding height) is the same at the start end treatment welded portion and the tandem welded portion. It is preferable to set to. The set position of the starting end processing welding start point P1 from the welding line starting point Ps and the setting position of the tandem welding start point P2 from the welding line starting point Ps are 2
If it is less than 0 mm, the shape of the weld bead at the start end treatment welded portion tends to be defective. On the other hand, when it exceeds 60 mm, the welded portion at the start end is too long, which causes a decrease in welding efficiency. The setting range is more preferably 25 to 35 mm.

In this start end treatment welding, first,
(A) Leading edge treatment A trailing electrode is positioned at the welding starting point P1 and an arc is generated only at the trailing electrode to start the welding line starting point P.
Start torch running toward s. (B) Next, the torch angle of the trailing electrode is changed so that the advancing angle is in the range of 2 to 45 ° toward the welding line starting point Ps direction. By setting the torch angle to the advancing angle within the above range, the arc of the trailing electrode can be directly applied to the welding line starting point Ps located at the corner with the interference member, and the welding line starting point P located at the corner.
In s, good penetration and familiarization of weld beads can be obtained. If the torch angle is less than 2 ° advancing, the above effect cannot be sufficiently obtained. On the other hand, if the torch angle exceeds 45 ° advancing, the torch tilts too much, causing a problem such that the lower end of the torch nozzle contacts the work. . More preferably, the advancing angle is in the range of 5 to 30 °. (C) When the trailing electrode reaches the welding line starting point Ps, the torch travel is temporarily stopped. In this case, the torch traveling temporary stop time at the welding line starting point Ps is preferably in the range of 0.3 to 3.0 seconds. If the torch travel suspension time is less than 0.3 seconds, the arc hitting at the welding line start point Ps is insufficient and the weld bead is not well fitted. On the other hand, if it exceeds 3.0 seconds, the welding amount becomes excessive and the bead becomes too large. The shape becomes defective. This torch travel suspension time is more preferably in the range of 0.5 to 2.0 seconds. In addition, when performing the leading edge treatment welding while weaving the trailing electrode, the torch traveling may be temporarily stopped at the welding line starting point Ps while continuing the weaving operation of the trailing electrode. (D) Next, after the traveling is temporarily stopped, the torch traveling direction is reversed, the torch angle of the trailing electrode is returned to the torch angle during tandem welding, and when the leading electrode reaches the tandem welding starting point P2, the leading electrode arcs. To start tandem welding. In this way, the starting end treatment welding is performed by the single arc welding using only the trailing electrode at the starting end treatment welding starting point P1 → the welding line starting point Ps → the tandem welding starting point P2.

Next, at the tandem welding start point P2 → tandem welding end point P3, tandem arc welding is performed in which a welding bead is formed by the leading electrode and the trailing electrode.

That is, (e) When the leading electrode reaches the tandem welding start point P2, an arc is generated in the leading electrode to start the tandem welding, the tandem welding proceeds, and the trailing electrode ends at the tandem welding end point P3. When it reaches, the arc of the trailing electrode is stopped. In this way, tandem arc welding is performed with the leading electrode and the trailing electrode at the tandem welding start point P2 → tandem welding end point P3.

Next, at the tandem welding end point P3 → the welding line end point Pe → the end treatment welding end point P4, the termination treatment welding is performed in which the welding beads are formed by the single arc welding using only the preceding electrode.

The tandem welding end point P3 and the terminating welding end point P4 on the welding line are the welding line end point Pe.
It is better to set (teach) the position in the range of 20 to 60 mm away from the welding line starting point Ps side. The tandem welding end point P3 at which the arc of the trailing electrode is stopped is set apart from the welding line end point Pe by a distance of (interelectrode distance) + (predetermined distance). The inter-electrode distance between the leading electrode and the trailing electrode is, for example, 15 mm. The P on the welding line
The 3 points and the P4 point may be set at different positions,
It is preferable to set the same position (coordinate position) from the point that the weld bead height (welding height) is the same in the terminating welded portion and the tandem welded portion. The setting position of the tandem welding end point P3 from the welding line end point Pe and the setting position of the termination processing welding end point P4 from the welding line end point Pe are 2
If it is less than 0 mm, the weld length of the termination welded portion is too short, and the weld bead shape is likely to be defective. On the other hand, when it exceeds 60 mm, the welded portion at the start end is too long, which causes a decrease in welding efficiency. The setting range is more preferably 30 to
It is 45 mm.

In this termination welding, first,
(F) After the arc of the trailing electrode is stopped at the tandem welding end point P3, the leading electrode that is torch traveling toward the welding line end point Pe is 2 to 45 toward the welding line end point Pe direction. The torch angle of the leading electrode is changed so that the advancing angle is in the range of °. By setting the torch angle to the advance angle within the above range, the arc of the preceding electrode can be directly applied to the welding line end point Pe located at the corner with the interference member, and the welding line end point Pe located at the corner is good. Good penetration and weld bead familiarity can be obtained. If the torch angle is less than 2 ° advancing, the above effect cannot be sufficiently obtained. On the other hand, if the torch angle exceeds 45 ° advancing, the torch tilts too much, causing a problem such that the lower end of the torch nozzle contacts the work. . More preferably 5 to 30 °
Is the advancing angle in the range. (G) When the preceding electrode reaches the welding line end point Pe, the torch travel is temporarily stopped. In this case, the torch traveling temporary stop time at the welding line end point Pe is preferably in the range of 0.3 to 3.0 seconds. When the torch travel suspension time is less than 0.3 seconds, the arc hits at the welding line end point Pe are insufficient and the welding bead is not well adapted. On the other hand, when it exceeds 3.0 seconds, the welding amount becomes excessive and the bead becomes excessive. The appearance and bead shape will be defective. This torch travel suspension time is more preferably in the range of 0.5 to 2.0 seconds. When the leading end process welding is performed while weaving the leading electrode, the torch travel may be temporarily stopped at the welding line end point Pe while continuing the weaving operation of the leading electrode.

(H) Next, after the traveling is temporarily stopped, the torch traveling direction is reversed, the torch angle of the leading electrode is returned to the torch angle during tandem welding, and when the leading electrode reaches the termination processing welding end point P4, the torch is reached. The traveling is stopped and the crater processing is performed for a predetermined time under the crater processing conditions. The crater processing time is preferably in the range of 0.2 to 5.0 seconds. If the crater treatment time is less than the above range, the amount of welding to fill the recess of the bead crater is insufficient and crater cracking is likely to occur, while if it exceeds the above range, the amount of welding is excessive and the connection part with the tandem welded portion becomes The bead appearance deteriorates due to excessive swelling. The crater processing time is more preferably 0.5 to
It is in the range of 4.50 seconds. After this crater process, the arc of the leading electrode is stopped and the welding operation of this time is ended.

As described above, according to the tandem arc welding method of the present invention, when the work having the interference member at the start end and the end of the welding line is welded using the teaching regenerative welding robot, the work is welded. Based on the starting point welding start point P1, the welding line start point Ps, and the tandem welding start point P2 that have been taught in advance about the line, the torch is reciprocally moved at the starting end of the welding line, and a single arc is formed by the trailing electrode under predetermined welding conditions Welding is performed, and then the torch travels from the tandem welding start point P2 to the tandem welding end point P3 to perform tandem arc welding with the leading and trailing electrodes, and subsequently, the tandem welding end point P3 and the welding line taught in advance. End point Pe and termination processing welding end point P
Based on No. 4, the torch is reciprocated at the end of the welding line to perform single arc welding with the preceding electrode under predetermined welding conditions. Therefore, there is no welding defect over the entire welding line of the workpiece. It is possible to efficiently obtain various welds.

[0019]

FIG. 2 is a diagram showing the construction of a welding robot apparatus used for carrying out the tandem arc welding method according to the present invention. This welding robot device has 2
A multi-joint (6-axis) teaching-reproduction welding robot 2 to which the electrode-integrated torch 1 is attached, and a wire feeding device 4 for a leading electrode that feeds the leading electrode 3 made of a welding wire to the two-electrode integrated torch 1. And a welding power source 5 for the leading electrode that supplies power to the leading electrode 3, and a wire feeding device 7 for the trailing electrode that feeds the trailing electrode 6 made of a welding wire to the two-electrode integrated torch 1.
And a welding power source 8 for the trailing electrode that supplies power to the trailing electrode 6.
And a robot controller 9 for controlling the operation of the welding robot 2 and controlling the outputs of the welding power sources 5 and 8, and a teaching box 10.

Reference numeral 11 denotes a work in which an interference member exists at the start end and the end of the welding line, the leading electrode 3 cannot be located at the welding line start point Ps, and the trailing electrode is at the welding line end point Pe. It is a work that 6 cannot be positioned.
The two-electrode integrated torch 1 is one in which a common shield nozzle is attached to the tip of a holding body that holds the leading electrode torch barrel and the trailing electrode torch barrel side by side, and shield gas is welded to the welding portion. While being ejected toward the electrodes, the electrodes 3, 6 sent from the wire feeders 4, 7 are respectively energized to generate an arc. At the time of teaching, the teaching box 10 has a starting point processing welding start point P1, a welding line starting point Ps, a tandem welding starting point P2, a tandem welding ending point P3, a welding line ending point Pe, and a termination processing welding ending point for the welding line of the work. P
4 and the like to input such position information into the robot control device 9 or to set welding conditions such as welding current and input into the robot control device 9.

[0021]

EXAMPLE Using the welding robot apparatus, a workpiece made of steel having an interference member at the beginning and the end of the welding line is welded by the method according to the present invention and the method according to the comparative example, and the welding is performed. The quality of the result was evaluated.

Tables 1 and 2 show basic welding conditions. Table 1
In, the wire protrusion length (25 mm) is the distance between the tip of the chip and the base material (workpiece), and the distance between the electrodes (15 m
m) is the distance between the center lines of the electrodes at the position where the wire protrudes 25 mm from the tip of the chip. In Table 3,
Distance between welding line starting point Ps and starting end treatment welding starting point P1, distance between welding line starting point Ps and tandem welding starting point P2, distance between welding line end point Pe and tandem welding ending point P3, and welding line end point Pe and ending point The distance from the processing welding end point P4 is shown (see FIG. 1). In addition, Table 3 shows each torch angle and each torch traveling temporary stop time at the welding line start point Ps and the welding line end point Pe, the crater processing time, and the welding results together. FIG. 3 shows the groove cross-sectional shape of the work in the embodiment. In FIG. 3, the interference members at the starting end and the ending end of the welding line are not shown.

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

[Table 3]

The welding results will be described below. 9 ~
No. In the 16 comparative examples, the following welding defects occurred. That is, No. In the comparative example of No. 9, the welding line starting point Ps
Since the distance between the tandem welding start point P2 and the tandem welding start point P2 was more than 60 mm, the welding efficiency was poor because the starting end treatment welded portion was too long. No. In Comparative Example 10 on the contrary, since the distance between the welding line starting point Ps and the tandem welding starting point P2 was less than 20 mm, the connecting portion with the tandem welding portion was not smooth and the bead shape was poor. No. In Comparative Example No. 11, since the torch angle at the welding line starting point Ps was set to be vertical (advancing angle 0 °) instead of the advancing angle, welding was stopped at that point because the torch and the interference member were in contact with each other near the welding line starting point Ps. No. In the comparative example of 12, the welding line starting point Ps
Since the torch angle at 4 was set to an advance angle exceeding 45 °, the torch and the work contacted each other, so welding was stopped at that point.

No. In the comparative example of No. 13, since the torch travel temporary stop time at the welding line starting point Ps and the welding line ending point Pe is less than 0.3 seconds, the welding line starting point Ps
And the familiarity of the bead was poor at each of the welding line end point Pe. No. In the comparative example of No. 14, since the torch traveling temporary stop time at the welding line start point Ps and the welding line end point Pe exceeds 3.0 seconds, the welding amount is excessive at each of the welding line start point Ps and the welding line end point Pe. The bead appearance and bead shape became poor. No. In the comparative example of No. 15, the crater processing time at the termination processing welding end point P4 was less than 0.2 seconds, so the amount of welding was insufficient and crater cracking occurred. No. In the comparative example of No. 16, the crater processing time at the termination processing welding end point P4 exceeded 5.0 seconds, so the amount of deposition was excessive and the connection part with the tandem welded portion was excessively raised and the bead appearance was poor. .

On the other hand, in No. 1-No. In the eighth example, the weld beads have good running-in and penetration at the weld start and end portions, and the joining portion between the start end treatment weld bead and the tandem weld bead and the joining between the tandem weld bead and the end treatment weld beet. Both parts had a smooth bead appearance, and it was possible to efficiently obtain a sound weld with no weld defects over the entire length of the weld line.

[0029]

As described above, according to the tandem arc welding method of the present invention, when a work having an interfering member at the start end and the end of the welding line is welded using the teaching regenerative welding robot. , A starting electrode treatment welding start point, a welding line starting point, and a tandem welding starting point which are taught in advance about the welding line of the workpiece, and the torch is reciprocally moved at the starting end portion of the welding line, and the trailing electrode is used under predetermined welding conditions. Performs single arc welding, then torch travels from the tandem welding start point to the tandem welding end point to perform tandem arc welding with the leading and trailing electrodes, and subsequently, subsequently teaching the tandem welding end point and welding line end point. Based on the welding end point, the torch is reciprocated at the end portion of the welding line to move the torch under predetermined welding conditions. Since is obtained to perform the single arc welding, it is possible to obtain a good efficiency of sound welds without welding defects throughout the weld line length of the workpiece.

[Brief description of drawings]

1 is a view for explaining a tandem arc welding method according to the present invention, which is a teaching point Ps,
It is a figure which shows Pe and P1-P4.

FIG. 2 is a diagram showing a configuration of a welding robot apparatus used for carrying out the tandem arc welding method according to the present invention.

FIG. 3 is a diagram showing a groove cross-sectional shape of a work in the example.

FIG. 4 is an interference member (side plate) at the start end and the end end of the welding line.
It is a figure which shows an example of the work which exists.

[Explanation of symbols]

1 ... 2 electrode integrated torch 2 ... Teaching regenerative welding robot 3 ... Leading electrode 4 ... Leading wire feeding device 5 ...
Leading electrode welding power source 6 ... Trailing electrode 7 ... Trailing electrode wire feeding device 8 ... Trailing electrode welding power source 9 ... Robot control device 10 ... Teaching box 11 ... Workpiece P1 ... Start processing welding start point Ps ... Welding Line start point P2
… Tandem welding start point P3… Tandem welding end point P
e ... Welding line end point P4 ... Termination processing Welding end point

Claims (2)

[Claims] 1. A teaching regenerative welding robot is equipped with a two-electrode integrated torch or two single-electrode torches, and a leading electrode and a trailing electrode, which use a welding wire as a consumable electrode, are arranged in a predetermined direction in a welding line of a workpiece. When tandem arc welding is performed with the gas shield welding method by arranging with a distance between electrodes, the welding line starting point and the welding line ending point are taught in advance about the welding line of the work. A start end treatment welding start point and a tandem welding start point are taught at positions separated by a predetermined length on the welding line end point side, and tandem welding ends at positions separated by a predetermined length on the welding line start point side from the welding line end point. Point and end processing welding end point are taught, the trailing electrode is positioned at the starting end processing welding starting point, the arc is generated only in the trailing electrode, and the torch travel is started, The torch angle of the trailing electrode is changed to the forward angle, and when the trailing electrode reaches the welding line starting point, the torch traveling is temporarily stopped, and then the torch traveling direction is reversed, and the torch of the trailing electrode is reversed. The angle is returned to the torch angle during tandem welding, and when the leading electrode reaches the tandem welding start point, an arc is generated in the leading electrode to start tandem welding, and tandem welding proceeds and the trailing electrode causes the tandem welding to proceed. When the welding end point is reached, the arc of the trailing electrode is stopped, and then the torch angle of the leading electrode is changed to the forward angle, and when the leading electrode reaches the welding line end point, the torch travel is temporarily stopped. After that, the torch traveling direction is reversed, the torch angle of the preceding electrode is returned to the torch angle during tandem welding, and the torch angle is reached when the preceding electrode reaches the termination welding end point. A tandem arc welding method characterized in that after stopping the C-travel and performing crater treatment for a predetermined time under the crater treatment condition, the arc of the preceding electrode is stopped to terminate the welding operation. 2. The starting point treatment welding start point and the tandem welding start point are set at positions within a range of 20 to 60 mm away from the welding line start point on the welding line end point side, and after the welding line start point. The torch angle of the row electrode is set to an advance angle in the range of 2 to 45 °,
The torch traveling temporary stop time at the welding line start point is set to a range of 0.3 to 3.0 seconds, the tandem welding end point and the termination treatment welding end point are from the welding line end point to the welding line. 20-60mm on the starting point side
Be set to a position in a distant range, the torch angle of the leading electrode at the end point of the welding line is set to a forward angle in the range of 2 to 45 °, the torch traveling temporary stop at the start point of the welding line The time is set to a range of 0.3 to 3.0 seconds, and the crater processing time is set to a range of 0.2 to 5.0 seconds. Tandem arc welding method.