JPH08150473A - Method for automatically welding tube and tube like part and device therefor - Google Patents

Abstract

PURPOSE: To execute welding of having a uniform and smooth appearance without an internal defect at the welding bead part by arranging each one of automatic welding machine at both sides of the plane containing the axis of a tube and the axis of a tube like part. CONSTITUTION: When a welding torch A5 reach a welding bead joining part, the starting signal is emitted to a welding torch B6 side positioning at the opposite side, based on it, the welding torch B6 is moved to the welding bead joining part, and a welding wire is inserted inside the arc of the top end part of the welding torch A5 executing welding. When the arc is generated at the welding torch B6 side, the signal is transmitted to the welding torch A5 side, and the arc of the welding torch A5 side is cut off. The welding torch B6 continues welding as it is, reaches the arc start position of the welding beginning position and welding is finished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to welding a stub of a boiler header having a narrow gap between stubs, a tube panel and a header, and a welding torch continuously around the stub or tube to be welded. The present invention relates to an apparatus and method capable of performing extremely highly reliable welding that does not cause internal defects such as arc start mistakes in the weld bead joint portion and has a uniform and smooth appearance when it is not possible to make one round. .

[0002]

2. Description of the Related Art A first example of prior art relating to welding of a tube and a header when a welding torch cannot be made around the tube to be welded once is disclosed in Japanese Patent Laid-Open No. 57-159290. There is a way. According to the conventional technique, the tube panel is set up by aligning the end of the tube panel with the header,
An automatic welding device composed of an automatic welding torch and a drive mechanism that can move and rotate in three dimensions is arranged on both sides of the tube panel, and a welding arc is generated by sending a current from a single welding power source to the automatic welding device. By alternately generating and automatically rotating the automatic welding torches on both sides in semi-relays on one side, the joint between the tube panel and the header is welded all around.

As a second example of the prior art, Japanese Patent Laid-Open No. 57-
There is a method described in Japanese Patent No. 159272. Similar to the above-mentioned first prior art, the prior art is an automatic welding torch which is erected by aligning the ends of the tube panel with the header to stand the tube panel and moving and rotating in three dimensions on both sides of the tube panel. An automatic welding device consisting of a drive mechanism is arranged, and the front side half circumference of the tube-header joint is automatically welded by the front side automatic welding torch, and at the same time, the other side semicircle is also automatically welded by the same device and operation. At that time, by setting a slight time lag such as starting the welding on the opposite side, starting the welding on the opposite side when the molten metal in the front welding part is semi-solidified, the front side and the opposite side The molten weld bead is obtained at the weld seam part of.

As a third example of the prior art, Japanese Patent Application Laid-Open No.
There is a welding method described in JP-A-9-156580.
According to the prior art, two welding machines for arc welding the cross joints of steel pipes by semicircles are arranged, and when the arc of one welding reaches a bead joint, both welding machines are in an arc generation state. Thus, the arc can be taken over by the other welder without interrupting the arc of the bead joint of the one welder, and the cross joint can be continuously welded.

[0005]

When the object to be welded cannot circulate a single welding torch once, welding is performed using a plurality of welding torches. Processing becomes most important. As a countermeasure against this problem, the above-mentioned conventional technique uses two welding torches to perform welding on each semicircle, so that a beautiful weld bead can be obtained with minimal weld defects at the weld seam. It can be said that it is an excellent method that can achieve a certain purpose in each case. However, the above-mentioned conventional techniques still have the problem that the following improvements are desirable.

First, in the first prior art example, 1
The welding power source is used to alternately switch the output of the welding power source for each semicircle of the tube, and the welding is performed sequentially.
The arc is connected in a relay manner by switching the welding power supply output changeover switch, and it is possible to obtain a continuous and beautiful weld bead appearance without a seam, as if one arc continuously rotates and welds around the tube. It has become.

However, it is difficult to say that the arc is continuous because the arc switching operation is performed by the changeover switch and the arc is cut off for a moment. This means that, for example, as shown in Fig. 9 (a), the robot on the receiving side may have an arc start error, weld defects such as poor fusion or poor fusion inside the bead joint, or uniform beading. It is impossible to completely eliminate the possibility that the appearance may not be obtained.

Next, in the second prior art example, automatic welding of one side of the joint portion of the tube and the header is started, and then a slight time lag is set and the metal of the welded portion is welded to the opposite side during semi-solidification. By starting the welding of 1), the occurrence of defective fusion or defective fusion between the welded parts on both sides is suppressed, but the excess amount of beads in the welded part increases, and problems may occur during multi-layer welding. Have sex. Further, since the both sides are welded at the same time, the temperature of the pipe material may rise, which may cause deformation.

Further, in the third prior art, the welding machine on both sides of the bead splicing part is set in an arcing state, the arc on the arc sending side is cut off, and the arc is passed to the welding machine on the arc receiving side. Therefore, the lap time is required to keep both welding machines in the arcing state at the same time, and the arc position is detected (for example, the robot position signal or the visual sensor) to control the arc transfer. Therefore, the lap time becomes long. As a result, as shown in FIG. 9 (b), there is a problem in that the amount of excess bead increases, and in particular, in the case of so-called multi-layer welding in which the bead splices overlap, it is difficult to apply.

The present invention has been made in view of the above circumstances, and in welding a stub or the like of a boiler header in which the gap between the tubular parts is narrow due to a simple structure, an internal defect is generated in the weld bead joint. It is an object of the present invention to provide an extremely reliable apparatus and method capable of performing welding without a uniform and smooth appearance.

[0011]

The above object can be achieved by an automatic welding method and apparatus for a pipe material and a tubular component as set forth in the claims. That is, (1) in the automatic welding of the tubular member and the tubular member, in which the mounting pitch of the tubular member is small and the gap between the tubular members is narrow, and the welding torch cannot continuously make one round around the tubular member to be welded, A welding torch that can move and turn in three dimensions, a means for operating the welding torch, a means for controlling the operation of the welding torch, a means for monitoring the arc generation on the other side, and an arc generation on the other side When it is detected, a means for cutting off the output of the welding power source on the front side and a means for applying the welding power source according to a given signal constitute an automatic welding machine, and the automatic welding machine is connected to the pipe material. An automatic welding device for pipe materials and tubular parts, one on each side of the surface containing the shaft and the axis of the tubular part.

(2) The automatic welding device for pipe materials and tubular parts according to (1), wherein the means for monitoring the generation of the arc on the other side is a WCR relay or a current detection coil.

(3) A welding torch that can be moved and turned in three dimensions, a means for operating the welding torch, a means for controlling the operation of the welding torch, and a means for monitoring the generation of an arc on the other side. An automatic welding machine is configured having means for cutting off the output of the welding power source on the front side when the occurrence of the arc on the other side is detected, and means for applying the welding power source according to a given signal, One automatic welding machine is installed on each side of the surface including the axis of the pipe material and the axis of the tubular part, and an arc takeover point is provided at the back part of the pipe material, and one torch generates an arc and the tubular part When one half of the circumference of the torch is reached to reach the takeover point, the arc is generated by automatically inserting the wire into the arc from the torch on the other side of the torch to which welding power is applied, By means of monitoring the occurrence of At the same time as detecting the arc generation from the torch on the other side, the welding power supply output on the torch side that had generated the arc until then is cut off and the welding is transferred to the other side. An automatic welding method for pipe materials and tubular parts that welds half a turn.

(4) An operation time limit is provided in the means for monitoring the occurrence of an arc, and the welding work is stopped when the arc is not delivered within the operation time limit, (3) The pipe material and tubular part Automatic welding method. (5) The automatic welding method for a pipe material and a tubular component according to (3) or (4), wherein the means for monitoring the generation of the arc on the other side is a WCR relay or a current detection coil. Is. Hereinafter, the operation and the like of the present invention will be described based on Examples.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram for explaining the basic operation of the automatic welding method in the case of welding a stub of a header of a boiler as an embodiment of automatic welding of a pipe material and a tubular part according to the present invention. is there. As a means to monitor the occurrence of the arc on the other side and shut off the welding power source on the front side, a method using a WCR relay that directly activates the relay when the welding current flows, or a current accompanying the arc generation by a current detector There are various methods, such as a method of detecting a signal and shutting off the welding power source based on the detected signal. In the present embodiment, a case of using a WCR relay will be described.

In FIG. 1, 1 is a stub, 2 is a header,
3 is a robot A, 4 is a robot B, 5 is a welding torch A,
6 is a welding torch B, 7 is a welding power source A, 8 is a welding power source B,
9 is a WCR relay A, 10 is a WCR relay B, 11 is a power source A, 12 is a power source B, 13 is a robot control panel A, 14 is a robot control panel B, 15 is a welding power source control device A, and 16 is a welding power source control device. B and 17 are external signal inputs A, 18 is an external signal input B, and 19 is a weld bead joint.

FIG. 1 shows a central stub 1 and a header 2.
On the side of the robot A3 described on the left side of the figure, the circuit of the WCR relay A9 in the welding power source A7 that is in contact with the power source A11 is in a formed state, and the welding power source control device A15 in the robot control panel A13 is in the state of being formed. 2 shows a state in which the circuit is closed and the welding torch A5 is energized to weld the stub 1 and the header 2.

At this time, the robot B4 side shown on the right side of FIG. 1 is connected to the power source B12 by the WCR relay B.
10 and the welding power source control device B16 in the robot control panel B14 are in the state where the circuit is opened.

External signal input B in the robot control panel B14
One end of 18 is a WCR in the welding power source A7 on the robot A3 side
It is connected to the relay A9 and the other side (robot A3
It is in a state where it is monitored whether or not the arc current surely flows from the welding torch A5 (on the side). At this time, the welding torch B6 on the side of the robot B4 is at the retracted position, which is separated from the position to receive the arc by about 10 mm to the outside.

The welding of the stub 1 and the header 2 is continued on the robot A3 side, and when the welding position reaches the joint portion 19 of the welding bead, a start signal is transmitted to the robot B4 side. Based on this, the robot B4 side is activated based on a predetermined program, first the welding torch B6 moves to the arc joint, the welding power source control device B16 closes the circuit, and the arc of the welding torch A5 tip that is performing welding. Insert the welding wire inside.

Since a large arc current flows in the arc, when the welding wire enters to a predetermined position, the arc surely and inevitably also occurs in the welding torch B6 of the robot B4. When an arc occurs, the circuit of the WCR relay B10 on the robot B4 side is automatically formed. The signal of the WCR relay B10 is sent to the robot A3 side, and the robot A3 receiving the signal immediately turns off the arc of the robot A3 itself by the welding power source control device A15. This ensures that the arc is transferred from the robot A3 side to the robot B4 side.

The arc receiving side generates an arc, and the arc passing side cuts the arc by the signal of the WCR which detects the arc generation, so that the arc cut at the welded portion cannot occur. On the other hand, since the series of operations is processed by the electric signal, the time during which the arc is generated on both the arc receiving side and the arc passing side is practically equal to zero, and the arcs from both welding torches are wrapped. The phenomenon that the weld bead is raised more than necessary due to the above does not occur.

FIG. 2 is a view for explaining the movement of the welding torch in the above welding operation. The central stub 1 shown in FIG.
When welding the header 2 and the header 2, first, at the position of the arc start position 20, welding is started by the welding torch A5, and welding is performed along the welding line between the stub 1 and the header 2 while the welding is continued as indicated by the arrow. Proceed in the clockwise direction to reach the weld bead joint 21.

When the welding torch A5 reaches the welding bead joint portion 21, a starting signal is transmitted to the welding torch B6 side located on the opposite side, and the welding torch B6 moves to the welding bead joint portion 21 based on it. The welding wire is inserted into the arc at the tip of the welding torch A5 during welding.

When the welding torch B6 side generates an arc, the signal is sent to the welding torch A5 side to cut off the arc on the welding torch A5 side. The welding torch B6 continues welding the stub 1 and the header 2 as it is, reaches the arc start position 20 of the welding start position, and when the welding is one pass, the welding is finished at that position.

When the welding to be welded has two passes, welding is performed along the welding line indicated by a from the arc start position 20 as shown in FIG.
In, at the welding torch located on the opposite side across the stub 1, the arc is joined to perform welding along the welding line shown in b, and the initial arc start position 20 is reached. In FIG. 3, reference numeral 24 indicates the traveling direction of the welding torch. The welding torch that has reached the arc start position 20 moves to the position of the weld bead joint portion 22 in FIG. 3 while performing welding.

In the weld bead joint portion 22, as in the case of the weld bead joint portion 21 described above, the arc is joined to the arc receiving side welding torch located on the opposite side with the stub 1 interposed therebetween, and the welding torch of the receiving side is formed. The welding torch on the arc passing side is cut by the arc generation signal.

The welding torch in which the arc is connected at the weld bead joint 22 performs welding along the welding line of c in FIG. 3, and the welding torch located at the opposite side with the stub 1 sandwiched again at the weld bead joint 23. The welding torch receiving the arc welds along the welding line of d, and completes the welding when it reaches the welding bead joint 22.

In addition, when the welding is a multi-pass multi-pass welding of two or more passes, the above-mentioned operation is repeated to overlap the welding beads, so that an internal defect does not occur in the welding bead joint portion due to the break of the arc. It also makes it possible to carry out welding with a uniform appearance. FIG. 4 is a schematic view showing a cross section of a 2-pass heap weld bead joint welded by the welding method according to the present invention.

5 to 6 are overall views of the stub 1 and the header 2 based on the header stub automatic welding apparatus according to the present invention when they are welded. FIG. 5 is a plan view thereof and FIG.
FIG. 4 is a view (side view) taken along the line aa in FIG. In FIGS. 5 and 6, two arc welding robots, robot A3 and robot B4, are used, and a gantry type traveling device 30 that travels each arc welding robot in parallel with the axis of the header 2 is used. It is mounted so that it can move vertically.

FIG. 7 is a perspective external view of the header 2 in which the stub 1 is welded at a small pitch, which is the object of the present invention, and FIG. 8 is a part of the header 2 in which the stub 1 and the stub 1 are welded. FIG.

[0032]

As described above, according to the present invention, as described in the above detailed description of the invention, the stub mounting pitch is small, the gap between the stubs is narrow, and the welding torch surrounds the stub to be welded. For automatic welding of boiler header stubs, etc. that cannot make one continuous turn, use two welding torches and insert the welding torch wire on the arc receiving side into the arc of the welding torch on the arc passing side. Then
Detects the occurrence of arc current in the welding torch on the arc receiving side,
By shutting off the output of the welding power source of the welding torch on the arc passing side based on the signal, there is no risk of an arc start mistake on the arc receiving side. It is possible to eliminate the risk of occurrence of welding defects such as poor melting and poor fusion in the weld bead joint portion due to temporary stop of the arc. The time at which each welding torch simultaneously arcs (wraps) is near zero, which allows for a beautiful, uniform bead appearance. Since no extra bead build-up occurs at the weld bead joint, it is possible to achieve welding with no internal defects and a uniform appearance even during multi-layer build-up welding.

[0033]

[Brief description of drawings]

FIG. 1 is a diagram illustrating a basic operation of a header stub automatic welding method according to the present invention.

FIG. 2 is a view for explaining the movement of the welding torch in the header stub automatic welding method according to the present invention.

FIG. 3 is a diagram for explaining the movement of the welding torch when the welding is performed in a two-pass manner in the header stub automatic welding method according to the present invention.

FIG. 4 is a schematic view showing a cross section of a 2-pass helix weld bead joint welded by the welding method according to the present invention.

FIG. 5 is an overall plan view at the time of welding the stub 1 and the header 2 based on the header stub automatic welding apparatus according to the present invention.

FIG. 6 is a view (side view) taken along the line aa in FIG.

FIG. 7 is a perspective external view of a header in which stubs are welded at a small pitch, which is the object of the present invention.

FIG. 8 is a partially broken side view of the header of the present invention, in which the stubs are welded at a small pitch and the stubs are welded together.

FIG. 9 is a view showing a cross section of a weld bead portion during welding in the conventional technique.

[Explanation of symbols]

 1 Stub 2 Header 3 Robot A 4 Robot B 5 Welding torch A 6 Welding torch B 7 Welding power source A 8 Welding power source B 9 WCR relay A 10 WCR relay B 11 Power source A 12 Power source B 13 Robot control panel A 14 Robot control panel B 15 Welding power supply control device A 16 Welding power supply control device B 17 External signal input A 18 External signal input B 19, 21, 22, 23 Weld bead joint portion 20 Arc start position 24 Welding torch traveling direction 30 Traveling device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Taku Suga 1 Niihama-cho, Chuo-ku, Chiba, Chiba Prefecture Kawasaki Heavy Industries Ltd. Chiba factory (72) Inventor Chiaki Ito 1 Niihama-cho, Chuo-ku, Chiba-shi Kawasaki Heavy Industry Co., Ltd. Chiba Plant (72) Inventor Mitsuo Suzaki 1 Shinhamacho, Chuo-ku, Chiba City, Chiba Prefecture Kawasaki Heavy Industry Co., Ltd. Chiba Plant (72) Inventor Hiroyuki Matsumura 3-1, Higashikawasaki-cho, Chuo-ku, Kobe City No. 1 Inside the Kobe Factory of Kawasaki Heavy Industries, Ltd. (72) Inventor Shigeru Nakayama 3-1-1 Higashikawasaki-cho, Chuo-ku, Kobe City Inside the Kobe Factory of Kawasaki Heavy Industries, Ltd. (72) Toshio Hasegawa Higashi-kawasaki-cho, Chuo-ku, Kobe 3-1-1 Kawasaki Heavy Industries, Ltd. Kobe factory (72) Inventor Shoji Takeshi Higashikawasaki-cho, Chuo-ku, Kobe 3-1-1 1-1 Kawasaki Industry Co., Ltd. Kobe Factory (72) Inventor Masaki Tanaka 3-1-1 Higashikawasaki-cho, Chuo-ku, Kobe City Kawasaki Heavy Industries Ltd. Kobe Factory (72) Inventor Tetsuji Hattori 3-chome, Higashikawasaki-cho, Chuo-ku, Kobe No. 1 Kawasaki Heavy Industries, Ltd. Kobe factory (72) Inventor Ken Koike 3-1-1 Higashikawasaki-cho, Chuo-ku, Kobe City Kawasaki Heavy Industries Ltd., Kobe factory

Claims (5)

[Claims] 1. In the automatic welding of a tubular member and a tubular member, in which the tubular member has a small mounting pitch and the gap between the tubular members is narrow, and the welding torch cannot continuously make one round around the tubular member to be welded, A welding torch that can move and turn in three dimensions, a means for operating the welding torch, a means for controlling the operation of the welding torch, a means for monitoring the arc generation on the other side, and an arc generation on the other side When it is detected, the means for cutting off the output of the welding power source on the front side, and the means for applying the welding power source in accordance with the given signal constitute an automatic welding machine, An automatic welding device for pipe materials and tubular parts, characterized in that one unit is provided on each side of a surface including the shaft and the axis of the tubular part. 2. A means for monitoring the occurrence of an arc on the other side comprises:
The automatic welding device for pipe materials and tubular parts according to claim 1, which is a WCR relay or a current detection coil. 3. A welding torch capable of moving and turning in three dimensions, means for operating the welding torch, means for controlling the operation of the welding torch, means for monitoring the arc generation on the other side, and the other. When the occurrence of the arc on the side is detected, a means for cutting off the output of the welding power source on the front side and a means for applying the welding power source in response to a given signal constitute an automatic welding machine, One welding machine is installed on each side of the surface including the axis of the pipe and the axis of the tubular part, and the arc takeover point is provided at the back of the pipe, and one torch generates an arc and When reaching the takeover point by performing welding on one side of the torch, the wire is automatically inserted into the arc from the torch on the other side of the torch to which welding power is applied, and the arc is generated. By means of monitoring the outbreak At the same time as detecting the arc generation from the torch on the other side, cut off the welding power source output on the torch side that had generated the arc until then, and pass the welding to the other side. An automatic welding method for pipe materials and tubular parts, characterized in that welding is performed halfway around each side. 4. The welding operation is stopped when an operation time limit is provided in the means for monitoring the occurrence of the arc and the arc is not delivered within the operation time limit. Automatic welding method for pipes and tubular parts. 5. The means for monitoring the occurrence of the arc on the other side comprises:
The method for automatically welding a pipe material and a tubular component according to claim 3 or 4, which is a WCR relay or a current detection coil.