JPH1058139A - Method for welding intersection part of tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a welding method of tubular intersection to weld the crossing tubes capable of performing the multi-layer welding of connection tubes requiring complicated welding, e.g. in a case where a tubular base is welded to a base tube. SOLUTION: The data on the weld seam are prepared by inputting the outer diameter of a tube 1 to be welded, the diameter of a connection tube 2, the wall thickness and the groove angle. The groove shape is measured by an optical sensor arranged based on the data on the weld seam, and the positional coordinates of the weld seam and the groove width are detected. The data on the weld seam is calibrated to obtain the welding coordinates to provide the groove center line of a welding torch 4 by correcting the data on the weld seam by the positional coordinates of the weld seam, the welding torch is installed at the welding coordinates, and the multi-layer welding is successively performed with one-layer and one-pass welding in the vertical upward position on the tube to be connected with its axis horizontal with the weaving width corresponding to the groove width so as to be connected to the tube to be welded. The multi-layer welding of a three-dimensional saddle-shaped connection tube can be performed without teaching by a versatile articulated robot with excellent precision in an unmanned condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, connecting a nozzle for piping of a thermal power plant and a nuclear power plant to a mother pipe.
The present invention relates to a pipe intersection welding method for performing welding between a connected pipe and a connecting pipe that are arranged crossing each other.

[0002]

2. Description of the Related Art Welding lines are formed along the outer periphery of a connecting pipe in order to connect a connecting pipe and a connecting pipe arranged crossing each other, such as connecting a nozzle to a mother pipe. Has a complicated saddle shape, and the groove cross-sectional area of the weld formed in the circumferential direction of the connecting pipe changes sequentially. That is, FIG.
As shown in (a), the welding line of the welding to be attached to the mother pipe 1 as the connection pipe and performed along the outer periphery of the nozzle 2 as the connection pipe is based on the outer diameter of the nozzle 2 and the mother pipe 1. Is 1
, The welding line has a saddle-shaped shape in which the three-dimensionality becomes remarkable. Also, as shown in FIG. 5B, which is an enlarged view of a cross section taken along the line AA in FIG.
The groove width b changes as shown in FIG. 5C according to the circumferential angle of the nozzle 2 to be welded, that is, the nozzle angle θ, and the base of the nozzle 2 is changed. At present, automatic welding is delayed because welding with the pipe 1 requires an advanced welding technique.

[0003] For this purpose, the applicant of the present invention has proposed Japanese Patent Application Laid-Open No. 63-27867 to facilitate automatic welding of such a pipe intersection.
No.1 "Saddle-type welding line method at pipe intersection" was proposed. This proposal is based on the fact that, when welding a pipe intersection where a branch pipe (a nozzle) 2 intersects a main pipe 1, a groove 2 is formed on the nozzle 2.
Groove cross-sectional area S formed between groove surface and surface of mother pipe 1
However, the groove is formed to be constant over the entire circumference of the nozzle angle θ, and welding is performed. In this proposal, since the groove cross-sectional area S is fixed, the entire circumference of the nozzle 2 can be welded with the same number of passes, and not only the workability by manual welding is improved, but also automatic welding is facilitated. Is obtained.

A similar proposal has been proposed in Japanese Patent Publication No. 58-280.
There is also a proposal based on No. 32 "automatic multilayer welding method". In this proposal, in welding a pipe intersection where the nozzle 2 intersects the base 1, the groove processing angle KA provided on the nozzle 2 is changed to a normal line perpendicular to the base 1 from the point A where the groove 2 stops. Height is the nozzle angle θ
In each case, the welded portion is divided by a concentric cylinder having the same center on the axis of the mother tube 1 and the nozzle 2, and the position, angle, and position of the welding torch 4 are determined based on the division. The welding conditions are calculated and controlled, and the welding torch 4
Makes one round of the circumference of the nozzle 2 to complete the welding of one section of the above-mentioned division, and by continuing this, multi-layer welding is performed. Conventionally, welding is automatically performed. The purpose of the present invention is to automatically perform multi-layer welding at a pipe intersection where a mother pipe 1 and a nozzle 2 intersect, which could not be performed.

[0005] As can be seen from such proposals, attempts have been made to enable automatic welding by making the groove cross-sectional area S of the pipe intersection that varies with the nozzle angle θ constant. All of the automatic welding methods made in these proposals employ the method shown in FIG. That is, as shown in the figure, the conventional automatic welding method uses a nozzle 2 as a connecting pipe, which is set so that the central axis is vertical.
Above, a portable cylindrical coordinate system welding robot 18 is installed,
A method of performing multi-pass welding with a welding torch 4 in a horizontal position is employed.

In such a method in which welding is performed with the welding torch 4 in a horizontal position, the groove cross-sectional area S is increased, and the number of layers (the number of passes) is accordingly increased. For this reason, as shown in FIG. As described above, the welding of the groove cross-sectional area S becomes a single-layer, multi-pass lamination, and the welding torch 4 needs to accurately aim at the end of the shape of the front bead 19, and the operator always sets the aiming position of the welding torch 4 at all times. A complicated device that monitors and corrects, or performs an operation aiming at the end of the shape of the previous layered bead, and precisely sets the position of the welding torch 4 according to the operation result is required. There was a problem.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the conventional pipe intersection welding method, the present invention has been changed from a portable cylindrical coordinate system welding robot to a versatile articulated robot. Welding line data consisting of huge coordinate data required for multi-layer welding by multi-joint robots is not created by teaching one point at a time, but is automatically created. To measure the error existing in the actual shape, correct the welding line data, calibrate to the welding coordinates for setting the welding torch, and enable each welding position to be performed under certain welding conditions, In order to determine the groove processing angle at each welding position, and to set the welding posture of the connection pipe with a constant groove cross-sectional area to the standing and improving posture, and to make it a flat weld bead shape instead of a convex shape, One-layer one-pass welding To provide a pipe intersection welding method with a simple construction condition of one-layer one-pass welding while oscillating a welding torch with a weaving width corresponding to a groove width, which varies for each layer and each welding position. Make it an issue.

[0008]

Therefore, the method for welding a pipe intersection according to the present invention employs the following means.

(1) By inputting the outer diameter of a pipe to be welded such as a mother pipe, the outer diameter of a connecting pipe such as a nozzle, a wall thickness, and a groove processing angle, a multi-layered welding of a saddle-shaped welded portion is performed. A data creation process that automatically calculates welding line data by calculating the coordinates required to set the welding torch of the welding robot.

(2) An optical sensor is brought to the coordinate position of the welding line data created in the data creation step, and the weld is irradiated with light from a slit light source of the optical sensor, and the weld is obtained by a CCD camera. A measurement step of optically measuring the groove shape based on the image of (1) and detecting the welding line position coordinates and the groove width determined from the actual groove shape. The coordinates of the welding line position can be obtained by setting the center line of the groove bottom in the CCD camera image obtained in the measuring step.

(3) The welding line data created in the data creating step is compared with the welding line position coordinates measured in the measuring step, and the deviation between the two is corrected to welding line data. Is a welding step in which the welding torch is actually set to the welding coordinates, which is equal to the welding line position coordinates.

(4) The welding torch is placed at the welding coordinates of the connecting pipe whose groove is machined so that the central axis is horizontal and the groove cross-sectional area at each welding position in the circumferential direction is constant. At the same time, the welding torch is oscillated with the weaving width corresponding to the groove width obtained in the measurement process. And a welding step of connecting the connecting pipe to the connected pipe.

According to the pipe intersection welding method of the present invention, a versatile articulated robot can be adopted by adopting the above-mentioned means, and a three-dimensional shape can be obtained without performing coordinate teaching which is indispensable for the articulated robot. With the use of an optical sensor, the connection pipe can be welded to the connected pipe by multi-layer welding, which is a saddle-shaped shape and becomes a complicated weld, and the automatic welding is facilitated.

Further, the welding torch can be arranged as shown in FIG. 6 and rotated 360 ° around the connecting pipe (stub) to perform welding. In order to guide the welding torch to the weld, it is necessary to increase the groove width, and for this purpose, the groove cross-section becomes large, and in order to fill this groove cross-section, In contrast to this, the number of layers (the number of passes) of welding is increased. In the welding method according to the present invention, which is performed in the vertical position, the connecting pipe is set horizontally from the right by setting the axis of the connecting pipe horizontally. If the watch is shown on a clock face, the welding torch can be moved from around 6 o'clock to 3 o'clock to around 12 o'clock around 12 o'clock, and from around 6 o'clock to 9 o'clock until around 12 o'clock and around 12 o'clock. By rotating, welding can be performed in all positions of upward → vertical → downward. Although there is no need to perform the control in the energized enough, groove cross-sectional area can be reduced, thus, it is possible to layer 1-pass welding not possible in a horizontal position.

Further, the groove shape of the connecting pipe to be welded by the method of the present invention is such that the groove processing angle is machined so that the groove cross-sectional area at each welding position is constant. Since the groove surface of the other connected pipe forming the groove changes at each welding position, the groove center line and groove width at each layer and at each welding position change.

For this reason, in the present invention, the weaving center line and the groove width of the welding torch are changed to the welding coordinates measured by the optical sensor and the weaving width corresponding to the groove width, thereby forming each layer and each groove. Even if the groove center and groove width change at the welding position, the welding torch performs welding with a weaving width centering on the welding coordinates, so that one-layer one-pass welding can be easily performed.

This eliminates the need for the welding torch to accurately aim at the end of the shape of the front bead, and eliminates the need for the operator to constantly monitor and correct the aiming position of the welding torch. There is no need for an arithmetic unit for performing an operation aiming at the end of the shape of the layer bead and a complicated device for setting the position of the welding torch precisely at the position indicated by the operation result.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method for welding a pipe intersection according to the present invention will be described below with reference to the drawings. FIG. 1 is an overall view showing a pipe intersection welding apparatus applied to a first embodiment of a pipe intersection welding method according to the present invention.

As shown in FIG. 1, a mother pipe 1 as a connected pipe is provided.
The workpiece is installed such that the center axis of the nozzle 2 as a connecting pipe is horizontal. Further, as shown in FIG. 2, an articulated robot 3 having an optical sensor 9 provided with a welding torch 4, a weaving unit 5, a slit light source 10 and a CCD camera 11 is arranged on a wrist axis.

First, as shown in FIG. 3, the coordinates (X, Y, Z) of the welding line at a certain number of layers are determined by the pipe diameter DB of the mother pipe 1, the outer diameter DK of the nozzle 2 and the wall thickness t. , And groove machining angle KA
Can be obtained from Equation 1.

[0021]

(Equation 1)

The coordinate (X, Y, Z) data of the welding line obtained according to Equation 1 is transmitted to the robot control panel 7 by the personal computer 6 shown in FIG. The welding line data is automatically created by converting to the coordinate system of No. 3.

Before welding, the optical sensor 9 is brought near the coordinates (X, Y, Z) of the welding line data, and the slit light 12 incident on the groove 13 from the slit light source 10 is transmitted. When viewed from the oblique direction with the CCD camera 11, an image composed of the slit light 12 indicating the groove shape 13 can be obtained as shown in FIG. The center line at the bottom of the groove in this image is obtained as the welding line position coordinates 14, and the welding line automatically created from the displacement 16 between the welding line data 15 coordinates automatically created before and the welding line position coordinates 14. The coordinates of the data 15 are corrected to the same welding coordinates as the actual welding line position coordinates. Further, the weaving width at the time of welding is determined based on the groove width b calculated from the same image obtained by the CCD camera 11, and the weaving controller 8 controls the weaving width during welding of the welding torch 4.

The groove shape 13 of the nozzle 2 to be welded in the present embodiment is processed to a groove processing angle KA so that the groove cross-sectional area S at each welding position is constant. Since the groove face of the other mother tube 1, which forms the groove shape 13 together with 2, changes at each welding position, the center line of the groove bottom at each layer and each welding position, that is, the welding coordinates, And the groove width changes. However, welding coordinates 1
4 and the change in the groove width b are determined by the optical sensor 9 as described above.
By setting the welding line position coordinates 14 measured in the above and the groove width b measured by the optical sensor 9, in each layer and each welding position,
Even if the welding coordinates and the groove width b change, the welding torch 4 performs welding with a weaving width determined in accordance with the groove width b with the welding line position coordinates 14 as the center line, thereby performing one-layer one-pass welding. Can be performed accurately.

As shown in FIG. 6, the welding torch 4 is not rotated 360 ° around the nozzle 2 and welded. In the dial, the torch is turned up and down from around 6 o'clock to 3 o'clock to around 12 o'clock, and from around 6 o'clock to 9 o'clock until 9 o'clock around 12 o'clock. → Standing →
Welding is performed in a vertical position where welding is performed in all downward positions. Thereby, the groove cross-sectional area S for performing welding can be reduced, and one-layer one-pass welding, which was impossible in a horizontal posture, can be performed.

The above procedure is performed for each layer to complete the construction of multi-layer welding. In addition, about the groove of the nozzle 2,
As described above, the groove machining angle (KA) at the nozzle angle (θ °) so that the groove sectional area S at each welding position is equal to the groove sectional area S ₀ at the nozzle angle of 0 °. Is processed as a numerical value obtained by Expression 2.

[0027]

(Equation 2)

As described above, in the present embodiment, the nozzle 2
Although the present invention has been described with respect to a pipe intersection welding method for joining pipes, the present invention is also applicable to the joining of a general connecting pipe and a connected pipe which are arranged crosswise, such as when a branch pipe is joined to the mother pipe 1. It can be welded by a method.

[0029]

As described above, according to the pipe intersection welding method of the present invention, the structure shown in the claims is
Uses a versatile articulated robot, and without performing coordinate teaching, which is indispensable for an articulated robot,
It becomes possible to weld to a connected pipe by multi-layer welding of a connection pipe that has a three-dimensional saddle shape and is a complicated weld. In addition, since welding is performed in a so-called upright advance posture in which welding is performed by setting the axis of the connecting pipe to be horizontal, the groove cross-sectional area can be reduced.
Layer 1 pass welding becomes possible.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an entire pipe intersection welding apparatus applied to a first embodiment of a pipe intersection welding method according to the present invention;

FIG. 2 is a side view around the wrist axis of the articulated robot shown in FIG. 1,

FIG. 3 is a coordinate definition diagram of a nozzle as a connecting pipe to be welded and a mother pipe as a connected pipe;

FIG. 4 is a diagram showing an example of an image obtained by the optical sensor shown in FIG. 2,

FIG. 5 is a view showing a conventional pipe intersection welding situation;
5A is an overall perspective view, and FIG. 5B is an arrow view A in FIG.
5A is a detailed cross-sectional view of FIG. 5A, and FIG.

FIG. 6 is a schematic view showing a conventional pipe intersection welding device,

FIG. 7 is a view showing welding performed by the pipe intersection welding device shown in FIG. 6;
It is sectional drawing which shows a stratification situation.

[Explanation of symbols]

 Reference Signs List 1 mother pipe as connected pipe 2 nozzle as connection pipe 3 articulated robot 4 welding torch 5 weaving unit 6 personal computer 7 robot control panel 8 weaving controller 9 optical sensor 10 slit light source 11 CCD camera 12 slit light 13 groove Shape 14 Welding line position coordinates (welding coordinates) 15 Welding line data 16 Misalignment 18 Portable cylindrical coordinate system welding robot 19 Front bead θ Head angle S Groove cross-sectional area KA Groove machining angle A Groove stop DB Mother pipe Diameter DK nozzle diameter D Welding wire diameter b Groove width s Groove cross-sectional area

Claims (1)

[Claims] 1. A multi-pass welding of a connecting pipe having a groove processing angle such that a groove cross-sectional area at each circumferential position where welding is performed is substantially constant, to a pipe to be connected intersecting. In the pipe intersection welding method performed by performing, the outer diameter of the connected pipe,
And data of the outer diameter of the connection pipe, the thickness, and the data of the groove machining angle, and calculate the coordinates of the welded portion to be saddle-shaped, to create welding line data,
Based on the welding line data, measuring the groove shape with an optical sensor installed near the weld, welding line position coordinates, and a measuring step of detecting the groove width, the welding line position coordinates the welding data Correcting, the calibration step to the welding coordinates, and the welding pipe set to the welding coordinates, the welding torch set to the weaving width corresponding to the groove width, the connection pipe with the central axis horizontal, A step of welding the connected pipes in a one-layer, one-pass manner in a standing and advancing posture, and sequentially welding them in a multi-layered form.