JPH01138065A - Method and equipment for welding polyhedral structural body - Google Patents

Abstract

PURPOSE:To perform satisfactory welding of a hexagonal pipe by arrangeing a torch at an equal interval with its tip separated by 120 deg. in the peripheral direction of a hexagonal pipe and while maintaining the distance between the torch and the pipe constant, rotating the torch and performing welding to maintain depth of penetration constant. CONSTITUTION:The hexagonal pipe 6 is supported on a supporting part 7 of welding equipment 1. The torch 15 is arranged with its tip separated by 120 deg. in the peripheral direction of a hexagonal pipe end 6 and a rotary table 17 is rotated to rotate the torch 15 round the pipe 6. At that time, the distance between the tip of the torch 15 and the pipe 6 is maintained constant by an automatic gap adjusting mechanism 24. Further, these operations are entirely controlled by a control panel 11. By this method, since the depth of penetration can be maintained constant, the satisfactory welding can be performed.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method and device for welding a polyhedral structure, for example, a method and device for welding a hexahedral nuclear fuel assembly. .

``Prior art'' As a conventional welding method for this type of polyhedral structure, for example, when hexagonal tubes having a predetermined length are placed adjacent to each other in the length direction and connected by butt welding, It is known that an automatic welding machine with a single torch attached to a trolley is moved sequentially and continuously from the starting point to the ending point to weld along the welded part formed in the circumferential direction of a hexagonal tube. There is.

``Problems to be Solved by the Invention'' However, in the conventional method for welding a polyhedral structure described above, - a weld is formed in the circumferential direction of the polyhedral structure using a torch from the start point to the end point. Since welding is performed continuously from one side to the other, there is a temperature difference between the welded parts of the polyhedral structure and the unwelded parts, which causes thermal distortion. While the rear part of the torch rotates toward the other surface, the tip of the torch remains at the corner for a longer period of time than the surface, and the welding depth at the corner becomes deeper than the other surface. There were problems such as failure to form good beads.

The present invention has been made in view of the above-mentioned problems, and it is possible to prevent thermal distortion from occurring during welding to a polyhedral structure (also, to make the weld penetration depth between the face portion and the corner portion uniform). It is an object of the present invention to provide a method for welding a polyhedral structure and an apparatus therefor, which can form a good bead.

"Means for Solving the Problem" In order to solve the above problem, the method of the present invention includes a method in which a plurality of torches are arranged around the outer periphery of a structure at approximately equal rotation angles, At the same time, the torch is moved along the welding part while welding, and when the torch passes through a corner of the structure, the rear end side of the torch is moved from one side of the structure faster than the tip of the torch. The device of the present invention is arranged so as to be rotated toward the other surface, and the device of the present invention is spaced apart from the outer periphery of the structure at equal rotation angles, and the tip thereof is substantially perpendicular to the surface of the structure. and a rotary table for fixing the torches via a rotating mechanism and rotating the torches along the radial direction of the structure, the rotating mechanism being An arc-shaped turning rail fixed to the top of the rotating table, a turning table movably attached along the turning rail, and a welded part between the tip of the torch and the structure on the turning table. The torch is equipped with an automatic gap adjustment mechanism that attaches the torch to the structure so that it can move forward and backward in order to maintain a constant distance between the torch and the structure.

"Operation" According to the method and apparatus of the present invention, when the torch moves from one surface to the other surface at the corner of the polyhedral structure, the rear part of the torch is rapidly rotated by the rotation mechanism. In this case, the tip of the torch does not stay at the corner more than necessary, and is continuously positioned substantially perpendicular to the contour of the corner.

"Example" Hereinafter, the present invention will be explained with reference to the drawings.

Figures 1 to 5 are diagrams showing one embodiment of the present invention, in which the polyhedral structure welding method and device of the present invention are applied to joining hexagonal tubes forming the outer shell of a nuclear fuel assembly. Fig. 1 shows the case.

FIG. 2 shows the entire welding device, FIGS. 3 and 4 show the main parts of the welding device, and FIG. 5 shows the outer shell of a nuclear fuel assembly made of hexagonal tubes.

Reference numeral l in FIGS. 1 and 2 indicates a welding device for polyhedral structures (hereinafter simply referred to as "welding device"), and this welding device 1
is a base 2, an inverted type surface plate 3 rotatably attached to the end of this base 2, and two welding machines 5 attached to this inverted type surface plate 3 by a support 4. It consists of two support parts 7 for supporting a nuclear fuel assembly 6 which is a polyhedral structure attached to an inverted surface plate 3.

Further, reference numeral 8 is a welding power source for supplying current to the welding machine 5, 9 is a control panel for controlling the welding section, and 10 is a welding scaffold.

As shown in FIG. 5, the nuclear fuel assembly 6 consists of an upper handling head 6a, an intermediate trumpet tube 6b, and a lower entrance nozzle 6C, and the connecting portions of these are formed by hexagonal tubes. Welded portions R1 and R2 are formed along the circumferential direction of the outer periphery formed in a regular hexahedron.

As shown in FIG. 3 and FIG.
Three torches 15 are arranged at an angle of 20°), and each torch 15 is arranged so that its tip end is substantially orthogonal to each surface of the hexagonal tube 6. Therefore, each torch allows the receiver to weld two sides of the hexagonal tube 6.

Further, the torch 15 is connected to the torch 15 via a rotating mechanism 16.
rotary table 1 for rotating in the circumferential direction of the hexagonal tube 6
7, and the rotary table 17 is attached to the support base 4.
It is fixed to the inverted surface plate 3 by. The rotary table 17 is formed into a disk shape, and a fixing jig 1 is mounted at the center of the bottom of the rotary table 17.
8 is fixed, and an annular swing drive gear 19 is fixed to the inner peripheral surface of the swing drive gear 19.
The rotary table 17 is rotated around the hexagonal tube 6 by being driven by a rotation drive motor 18a fixed to the tip of the fixing jig 18.

The turning mechanism 16 has three group single rails 20 formed in an arc shape, spaced apart from each other at a rotation angle of 180 degrees on the upper part of the rotary table 17, and with the inner peripheral surface side facing the center of the rotary table 17. A swivel base 22 is attached to the outer periphery of the swivel rail 20, which is movable along the swivel rail 20 via holding rollers 21°21.21. An annular torch angle drive gear 23 is fixed to the outer circumference of each rotating table 22, and the torch angle drive gear 23 is driven by a torch angle drive motor 25 fixed to one outer circumference of the rotary table 17. The upper part of the rotary table 17 is rotatable in the circumferential direction around the tip of the torch 15.

Further, an automatic gap adjustment mechanism 24 is provided on the upper part of the swivel base 22, which allows the torch 15 to move forward and backward with respect to the hexagonal tube 6.
is attached, and the tip of the torch 15 is set to always maintain a constant distance from each surface of the hexagonal tube by this automatic gap adjustment mechanism 24.

Next, a method for welding a polyhedral structure using the welding apparatus of this embodiment configured as described above will be described.

First, the nuclear fuel assembly 6 is supported on the support part 7=7- of the welding device 1 by butting each hexagonal tube so that welds R1 and R2 are formed along the circumferential direction of the hexagonal tube, and The tip of the torch 15 of the welding machine 5 is positioned at R1 and R2. Next, the tips of the torches 15 of the welding machine 5 are spaced apart by 120 degrees in the circumferential direction of the hexagonal tube, and arranged so as to be substantially perpendicular to each surface, and then welding is started and the rotary table is moved by the rotation drive motor 18a. Rotate 17. As the rotary table 17 rotates, the tip of the torch 15 moves along the surface of the hexagonal tube 6 to weld the welding parts R1 and R2. At this time, the automatic gap adjustment mechanism 24 causes the tip of the torch I5 to adjust to the hexagonal shape. It moves forward and backward relative to the surface of the pipe and is adjusted to provide the optimum welding distance. As shown in FIG. 3, when the tip of the torch 15 reaches the corner of the hexagonal tube 6, the torch angle drive motor 25 rotates the torch drive gear 23, thereby moving the torch 15 to the tip of the torch. The object is rotated along the turning rail 20 around the center. Therefore, the rear part of the torch 15
The tip of the hexagonal tube 6 turns rapidly from one side to the other side with respect to the tip of the torch 5, and as a result, the tip of the torch passing through the corner is required to pass through the surface. It will not stagnate at the corner and will be located continuously at right angles to the contour of the corner. The torch 15, which has passed through the corner, welds the welded part while turning again in the circumferential direction on the other surface of the hexagonal tube 6, and then rapidly moves along the turning circle 20 at the corner again as described above. swivel,
Furthermore, move to other planes and use other torches! 5 reaches the starting point where welding started, the swing drive motor 24 stops, and welding is completed. Note that these operations are all controlled by the control panel 11.

As described above, according to the polyhedral structure welding method and device of this embodiment, one of the three saws arranged on the outer periphery of the hexagonal tube 6
In order to weld continuously from each starting point to the starting point of other torches 15 along the joints formed simultaneously in the circumferential direction of the hexagonal tube by torches 15, three sides of the hexahedron are welded at the same time. As a result, each side is heated evenly and approximately evenly heated.
This results in a temperature distribution with almost no temperature difference near the welded part of the hexagonal tube, and therefore no thermal distortion occurs.
At the corner of the hexagonal tube 6, the rear part of the torch 15 pivots toward the other side more rapidly than the tip, so the tip of the torch does not stay at the corner for a long time and is aligned with the contour of the corner. The weld penetration depth at the corners becomes uniform, similar to the surface part, and the weld penetration depth at the corners becomes uniform.
A good bead is formed.

Note that other embodiments other than those described above and technical matters will be described below.

(i) In the above embodiment, a hexagonal tube forming the outer shell of a nuclear fuel assembly was used as the polyhedral structure, but the present invention is not limited to this, and can be applied to any other polyhedral structure such as an octahedron or a hexahedron. Can be done. At this time, it is of course necessary to increase or decrease the number of torches used and arrange them at predetermined intervals to prevent thermal distortion from occurring in the polyhedral structure.

(11) In the above embodiment, two welding machines 5 are arranged on the inverted surface plate, but the invention is not limited to this, and two or more welding machines 5 may be arranged so that welding can be performed simultaneously. You can.

"Effects of the Invention" As described above, according to the method and apparatus for welding a polyhedral structure of the present invention, a plurality of torches are provided on the outer periphery of the polyhedron, and the torches are connected along the circumferential direction of the polyhedron. It is equipped with a rotating table for rotating the polyhedron, a rotating mechanism consisting of a rotating rail, a rotating base, and an automatic gap adjustment mechanism. Since welding is performed on the welding part while simultaneously moving the torch in the circumferential direction, there is no thermal distortion in the polyhedral structure, and when the torch passes through the corner of the polyhedron, the rear end side of the torch The torch is rotated from one side of the polyhedron to the other side faster than the tip of the torch, so that it is positioned continuously at approximately right angles to the outline of the corner. The tip does not stay in the corner for a long time, the penetration depth of the corner becomes uniform, similar to the surface part, and a good bead is formed. play.

[Brief explanation of the drawing]

1 to 5 show an embodiment of the present invention, FIG. 1 is a plan view showing the entire welding device for a polyhedral structure of the present invention, and FIG. 2 is a welding device for a polyhedral structure. 3 is a plan view of the welding machine, FIG. 4 is a side view of the welding machine, and FIG. 5 is a side view of the outer shell of the nuclear fuel assembly, which is a polyhedral structure. 5...Swivel mechanism, 6...Polyhedral structure (hexagonal tube. Outer shell of nuclear fuel assembly), +5 Torch, 16...
Swivel mechanism, 17... Rotating table, 20... Swivel rail, 22... Swivel base, 24 Automatic gap adjustment mechanism, r(I, R2... Welding part. Applicant: Mitsubishi Nuclear Fuel Co., Ltd. (~ Heku

Claims (2)

[Claims] (1) A polyhedral structure welding method for connecting at least two structures each having a polyhedron formed on the outer periphery such that a welded portion is formed along the circumferential direction, the welding method comprising: Welding is carried out by simultaneously moving a plurality of torches spaced apart at equal rotational angles along the welding area, and when the torches pass through a corner of the structure, the A method for welding a polyhedral structure, characterized in that the rear end side of the torch is rotated from one side of the structure to the other side faster than the front end side of the torch. (2) A polyhedral structure welding device that connects at least two structures each having a polyhedron formed on the outer periphery so that a welded portion is formed along the circumferential direction, the A plurality of torches are spaced apart at equal rotational angles and disposed so that their tips are substantially perpendicular to the surface of the structure, and the torches are fixed via a rotating mechanism, and and a rotating table for rotating the structure along the radial direction of the structure, and the rotating mechanism is attached to an arc-shaped rotating rail fixed to the upper part of the rotating table and movably along the rotating rail. a swivel base,
It is characterized by comprising an automatic gap adjustment mechanism that attaches the torch to the swivel base so as to be able to move forward and backward with respect to the structure in order to maintain a constant distance between the tip of the torch and the welded part of the structure. Welding equipment for polyhedral structures.