JPH11320092A - Nozzle automatic welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To equalize a groove shape at each position on a weld line, to facilitate the automation of welding, and to enable a volumetric inspection such as a radiographic test and an ultrasonic test. SOLUTION: The method is such that it is intended for the butt welding of a nozzle performed by providing a groove 3a, 3b on both the tube body 1 and the nozzle 2 to be welded to the tube body; that a welding equipment WE is used which operates by catching a welding position by means of a cylindrical coordinate system loaded on the head 4 of the nozzle 2; that the welding equipment is provided with a rotary shaft 6 rotating on the axial line of the nozzle 2, a radial direction shaft 7 movable along the radial direction of the nozzle 2, an axial direction shaft 8 movable along the axial direction of the nozzle 2, and an inclined shaft 9 arranged in inclination against the axial direction shaft 8; that the radial direction shaft 7, the axial direction shaft 8 and the inclined shaft 9 are operated synchronously with the rotary shaft 6; and that a welding torch 13 is moved based on the three-dimensionally curved welding line determined on calculation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nozzle automatic welding method applied when a nozzle is attached to a pipe body by welding.

[0002]

8 and 9 are a longitudinal sectional view and a transverse sectional view, respectively, for explaining a conventional nozzle welding method. In this conventional nozzle stub welding method, a simple short tubular nozzle 2 to be welded on the tube main body 1 is to be welded, and the center of the tube main body 1 is aligned with the through hole 1a opened in the tube main body 1. A method is adopted in which the nozzle 2 is placed on the outer surface and the nozzle 2 is joined to the pipe body 1 by fillet welding.

[0003]

However, in the above conventional nozzle welding method, the outer surface of the pipe body 1 to which the nozzle 2 is joined has a curved surface. There is a problem that the groove shape is different, automatic welding is difficult, and volume inspections such as a radiation transmission test and an ultrasonic inspection test cannot be applied.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to make a groove shape identical at each position on a welding line, thereby facilitating automatic welding. Another object of the present invention is to provide a nozzle automatic welding method to which a volume inspection such as a radiation transmission test and an ultrasonic inspection test can be applied.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to a butt welding of a pipe main body and a nozzle to be welded to the pipe main body, which is mounted on a head of the nozzle. Using a welding device that operates by capturing the welding position in the cylindrical coordinate system
The welding device includes a swivel axis that pivots on the axis of the nozzle, a radial axis that is movable in a radial direction of the nozzle, an axial axis that is movable in an axial direction of the nozzle, and A tilt axis is provided to be inclined with respect to the axial axis, and the radial axis, the axial axis, and the tilt axis are operated in synchronization with the pivot axis, and based on a three-dimensional curved welding line obtained by calculation. The welding is performed by moving the welding torch. Further, in the present invention, an arc voltage control axis is arranged on the axis closest to the welding torch among the turning axis, the radial axis, the axial axis, and the inclined axis, and the height of the welding torch at the time of multi-layer filling is arranged. The position control in the vertical direction may be performed, and at a plurality of positions in the circumferential direction of the welding groove, the actual groove position is confirmed with a welding torch, and the deviation amount between the center axis of the nozzle and the center axis of the welding device is determined. Can be detected, and the position of the three-dimensionally curved welding line obtained by calculation can be corrected to improve the accuracy.

[0006]

Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a welding target and an automatic welding device for the nozzle in the automatic nozzle welding method according to the embodiment of the present invention, and FIG. 2 is a cross-sectional view of the pipe body at the center position of the nozzle in FIG. FIG. The welding target of this automatic nozzle welding method is a nozzle 2 to be butt-welded to a predetermined portion of the tube body 1. A groove 3a for butt welding is formed in the pipe body 1. This groove 3a is
It is formed by processing a predetermined portion of the pipe body 1 so as to form a welding line along a three-dimensional curve on an intersection line with the virtual cylinder including the welded portion 5 integrated with the head 4 of the nozzle 2.

The nozzle 2 has a cylindrical head 4 projecting therefrom and a welded portion 5 following the lower end of the head 4 integrally formed on the outer periphery of the welded portion 5. A groove 3b for butt welding is formed by processing so as to face the groove 3a, and the head 4 is disposed so as to project perpendicularly to the pipe body 1. As shown in FIG. 2, the welded portion 5 is curved so as to form a part of the pipe main body 1 in accordance with the cylindrical curved surface of the peripheral wall of the pipe main body 1. The groove 3b is formed so as to form a substantially U-shaped groove 3 with the groove 3a on the side.
Are formed.

An automatic nozzle W for the nozzle used in this welding method.
E is a swivel shaft 6 that pivots on the axis of the nozzle 2, a radial axis 7 that can move in the radial direction of the nozzle 2, and an axial axis 8 that can move in the axial direction of the nozzle 2. An inclination axis 9 inclined with respect to the axial direction axis 8 and an arc voltage control axis for controlling an arc voltage (hereinafter referred to as an AV axis).
It is called C axis. ) 10, and a welding torch 13 is mounted via the AVC shaft 10. Further, the nozzle automatic welding apparatus WE includes a controller 14 that outputs a control signal for controlling the operation of each axis, and the controller 1
The position and the attitude of the welding torch 13 are controlled by the control signal output from 4.

The turning shaft 6 is mounted on the upper end of the head 4 of the nozzle 2 via a chucking mechanism 16. A straight guide cylinder 17 is fixed to the upper end of the rotating shaft 6 at right angles. The radial shaft 7 has a straight guide tube 19 fixed at one end to be orthogonally arranged and fixed thereto.
Are slidably supported in the radial direction. Axial axis 8
Has a curved guide tube 21 fixed to the lower end, and is slidably disposed in the axial direction of the nozzle 2 by a straight guide tube 19 at one end of the radial shaft 7.

The inclined shaft 9 has an inclined guide tube 23 fixed to one end thereof, is curved with the same radius of curvature as the curved guide tube 21, and extends in a direction intersecting the nozzle 2 with the curved guide tube 21. It is slidably supported. The AVC shaft 10 has a welding torch 13 attached to the tip, and the inclined guide cylinder 2
It is slidably guided by 3.

The controller 14 controls the turning axis 6, the radial axis 7, the axial axis 8, the tilt axis 9, and the
The positions and operations of the five axes of the VC axis 10 are simultaneously controlled.

An automatic welding method for a nozzle according to an embodiment of the present invention will be described in detail. Inclination angle K _T of the trajectory of the welding line and the welding torch 13, as shown in FIGS. 3, 4 and 5, X-axis the axis of the tube body 1, Y-axis horizontal line orthogonal to the axis line, the vertical line It is calculated and displayed using a cylindrical coordinate system with the Z axis. Welding torch when D _B the outer diameter of the tube body 1, the rotation angle of the wall thickness of the pipe body 1 T, the outer diameter of the nozzle 2 and D _K, the clockwise direction of the welding torch 13 with respect to the X-axis θ 13
The inclination angle K _T coordinates (X, Y, Z) and the welding torch 13 with respect to the Z-axis of the tip position of the (C point), theta, determined is expressed as follows by D _B, T and D _K of the function f Can be _{X = f 1 (θ, D} B, T, D K) Y = f 2 (θ, D B, T, D K) Z = f 3 (θ, D B, T, D K) K T = f 4 _{(θ, D B, T,} D K)

Therefore, in the automatic nozzle welding device WE,
In synchronization with the pivot axis 6, the radial axis 7, the axial axis 8,
By driving the inclined shaft 9 and the AVC shaft 10, welding is performed along a three-dimensional curved welding line. In FIG.
The intersection of the straight line SL passing through the coordinate origin and the center of the groove and the welding line locus LO on the outer surface of the pipe body 1 is represented by B, and the straight line SL and the pipe body 1
Assuming that the intersection point of the inner surface with the welding line locus LI is C, in the actual product, multi-layer welding from point C to point B shown in FIGS. 3 and 5 is performed. Is
According to the above-described method, the welding torch 13 is followed in the height direction by detecting the arc voltage during welding with the AVC shaft 10 attached to the tip of the inclined shaft 9 so that the welding torch 13 has a constant voltage. It can be handled by controlling the height position.

However, in the actual product, as shown in FIG. 6, due to an error in attaching the automatic nozzle WE to the head 4 of the nozzle 2 and a processing error of the groove 3b on the nozzle 2 side, etc. Nozzle 2
Does not always coincide with the central axis Ce2 of the automatic nozzle welding device WE, and there is a deviation between the calculated position of the welding torch 13 and the actual groove position.

Therefore, when the automatic nozzle WE is attached to the head 4 of the nozzle 2, θ becomes 0 °, 90 °, 180 °, 270 ° as shown in FIGS. 6 and 7. At each point, the tip of the welding torch 13 is moved to the center position of the groove 3 by using the four axes except the AVC axis 10, the swivel axis 6, the radial axis 7, the axial axis 8, and the inclined axis 9. Then, the amount of deviation between the calculated position and the actual position is detected by an encoder attached to the drive system of each axis.

Next, when the aforementioned θ is 0 °, 90 °, 180 °
°, 270 ° from the displacement detected at each position
Of the center axis of the nozzle WE with respect to the center axis of the nozzle WE in the X-axis direction, the Y-axis direction shift amount ΔY, and the Z-axis direction shift amount ΔZ, and the calculated welding torch 13
By adding these deviation amounts ΔX, ΔY, and ΔZ to the tip position of, it is possible to accurately track the welding line.

Here, in FIG. 6 and FIG.
°, 90 °, 180 °, 270 ° at the calculated position indicated by the mark ■ and the actual welding torch 1 indicated by the mark x
3 are δ0 °, δ90 °, and δ, respectively.
When expressed in terms of 180 ° and δ270 °, the components ΔX and ΔY of the shift amount in the X-axis direction and the Y-axis direction are as follows: ΔX = (δ0 ° + δ180 °) / 2, ΔY = (δ90 ° + δ270 °) / 2, When the shift amounts in the Z-axis direction when θ is 0 ° and 180 ° are represented by δZ0 ° and δZ180 °, respectively, the component of the shift amount in the Z-axis direction ΔZ is ΔZ = (δZ0 ° + δZ180 °) / 2. Therefore, the coordinates (X ′, Y ′, Z ′) of the actual tip position (C ′) of the torch 13 are X ′ = X + ΔX, Y ′ =
Y + ΔY, Z ′ = Z + ΔZ.

In the case of the automatic nozzle welding apparatus WE according to the embodiment of the present invention, among the turning shaft 6, the radial shaft 7, the axial shaft 8, and the inclined shaft 9, the position closest to the welding torch 13 is provided. By arranging the AVC shaft 10 on a certain inclined shaft 9, the position of the welding torch 13 in the height direction can be controlled at the time of multi-layer building, and multi-layer building can be performed with high accuracy. Then, the actual groove 3 with the welding torch 13
The position of the center axis of the nozzle 2 and the center axis of the welding device WE are detected, and the position of the calculated three-dimensional curved welding line is corrected to further improve the accuracy. There is an advantage that it can be achieved.

The present invention is not limited to the above embodiment, and various modifications and changes can be made. For example, the present invention can also be applied to a case where the nozzle 2 is arranged at an angle to the pipe main body 1 and welded.
It may be a shape, and may be an I shape when the thin tube main body 1 and the nozzle 2 are targeted. In addition, when detecting the shift amount between the calculated position and the actual position, the shift amount may be corrected at three or five or more positions.

[0020]

The present invention is intended for butt welding of a pipe main body and a nozzle to be welded to the pipe main body, so that the groove shape can be easily made identical at each position on the welding line. It is possible to avoid the difference depending on the position, using a welding device that operates by capturing the welding position in a cylindrical coordinate system attached to the head of the nozzle, a turning axis that turns on the axis of the nozzle, A radial axis movable along the radial direction of the nozzle, an axial axis movable along the axial direction of the nozzle, and an inclined axis inclined with respect to the axial axis are provided and synchronized with the pivot axis. By operating the radial axis, the axial axis, and the tilt axis, and moving the welding torch based on the calculated three-dimensional curved welding line, automatic welding is easy, and the radiation transmission test and The ability to apply volumetric inspections such as ultrasonic testing Achieve the. Also, in the present invention, the height of the welding torch at the time of multi-layer filling is arranged by arranging the AVC axis on the axis closest to the welding torch among the turning axis, the radial axis, the axial direction axis, and the inclined axis. By controlling the position in the direction, it is possible to perform multi-layer filling with high accuracy, check the actual groove position with a welding torch at multiple locations in the circumferential direction of the welding groove, and check the center axis of the nozzle and the welding equipment. If the amount of deviation from the central axis is detected and the position of the three-dimensionally curved welding line obtained by calculation is corrected, there is an advantage that the accuracy can be further improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a welding object and an automatic welding apparatus for a nozzle in an automatic nozzle welding method according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a tube main body at a center position of the nozzle in FIG. 1;

FIG. 3 is a plan view for explaining a welding line trajectory in the nozzle automatic welding method according to the embodiment of the present invention.

FIG. 4 is a front view of FIG. 3;

FIG. 5 is a sectional view taken along line aa ′ of FIG. 3;

FIG. 6 is a plan view for explaining a method of correcting a welding line locus in the automatic nozzle welding method according to the embodiment of the present invention.

7 is a cross-sectional view for explaining the relationship between the calculated position and the amount of displacement in FIG. 6 and the tip position of the actual welding torch after correcting the welding line locus.

FIG. 8 is a vertical sectional view for explaining a welding target and a welding method of a conventional nozzle welding method.

9 is a cross-sectional view of the tube main body at a center position of the nozzle in FIG. 8;

[Explanation of symbols]

 WE welding device 1 Pipe body 2 Sink 3, 3a, 3b Groove 4 Head 5 Welding part 6 Revolving axis 7 Radial axis 8 Axis axis 9 Incline axis 10 Arc voltage control axis (AVC axis) 13 Welding torch 14 Controller 16 Chucking mechanism 17, 19 Straight guide tube 21 Curved guide tube 23 Inclined guide tube

Claims (1)

[Claims] An object of the present invention is to use a welding apparatus for butt welding of a pipe body and a nozzle to be welded to the pipe body, which operates by grasping a welding position in a cylindrical coordinate system mounted on a head of the nozzle. ,
The welding device includes a swivel axis that pivots on the axis of the nozzle, a radial axis that is movable in a radial direction of the nozzle, an axial axis that is movable in an axial direction of the nozzle, and A tilt axis is provided to be inclined with respect to the axial axis, and the radial axis, the axial axis, and the tilt axis are operated in synchronization with the pivot axis, and based on a three-dimensional curved welding line obtained by calculation. A nozzle automatic welding method characterized by moving a welding torch for welding.