JPH0910931A - Welding equipment and welding method - Google Patents

Abstract

PURPOSE: To provide a welding equipment and a welding method to achieve the automatic welding of a whole longitudinal joint part of side plates of an LNG tank, etc. CONSTITUTION: In a welding equipment 10, a torch 12 is oscillatingly fitted to a slider 16 which is vertically moved along a guide rail 18. When a longitudinal joint part 42 of a lowest tank side plate 40 is welded using the welding equipment 10, the welding of the longitudinal joint part 42 is started with the tip of the torch 12 diagonally downward, and then, the torch 12 is oscillated so that the tip of the torch 12 is faced upward. After the torch angle of the torch 12 reaches the prescribed value, the torch 12 is moved upward with the torch angle unchanged. Because the torch 12 can be in the flat position, the welding of a part lower than the torch fitting position can be achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to welding for welding a butt joint between side plates in an LNG (liquefied natural gas) tank, an LPG (liquefied petroleum gas) tank, etc., particularly a vertical joint extending in a vertical direction. The present invention relates to an apparatus and method.

[0002]

2. Description of the Related Art Conventionally, for example, when welding a vertical joint portion between inner tank side plates in an LNG tank or an LPG tank by an automatic TIG (tungsten inert gas arc) welding device, the torch of the welding device is set slightly upward and its upward posture is taken. While maintaining this, the vertical joint portion of the side plate is automatically welded from the lower side to the upper side. This welding method is adopted because the upper side of the arc has a higher temperature than the lower side, so moving the torch from the lower side to the upper side is effective in effectively utilizing the heat.

[0003]

However, the conventional automatic T
In the IG welding device, since the torch is fixed in the upward state and the torch cannot be lowered below a certain height level, the lower part of the vertical joint portion of the lowermost side plate could not be automatically welded. . For this reason, it is usual to manually weld that portion, but there is a problem that the welding state differs between the manually welded portion and other automatically welded portions.

To solve this problem, a means of jacking up the lowermost side plate and welding the entire vertical joint portion of the side plate with an automatic TIG welding device can be considered, but the work becomes very large. The cost will also increase.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a welding apparatus and method for automatically welding all vertical joints between side plates of an LNG tank or the like.

[0006]

In order to achieve the above object, a welding apparatus according to the present invention comprises a guide rail extending in a vertical direction, a slider which moves up and down along the guide rail, and a swing in a vertical plane. Inert gas arc welding torches attached to the slider so that they can be moved, and drive means for swinging the torch.

Further, the present invention is a welding method for welding a vertical joint between steel plates such as a tank side plate, in which the welding device having the above-mentioned configuration is arranged adjacent to the vertical joint and the tip of the torch is directed obliquely downward. After starting the welding of the vertical joint in such a state, the drive means is controlled so that the tip of the torch faces upward, the torch is swung, and the torch angle reaches a predetermined torch angle. It is characterized in that the slider is moved upward along the guide rail in order to move the torch upward while maintaining the above condition.

[0008]

When the welding apparatus according to the present invention is used, the tip of the torch can be directed downward, so that the arc cannot be formed conventionally, that is, at the lower part of the vertical joint between the tank side plates at the bottom. It becomes possible to form an arc. Therefore, the lower part of the vertical joint can be welded by gradually swinging the torch upward from the downward direction, and by subsequently raising the torch, the entire vertical joint is continuously welded. You can

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings.

1 and 2 show an embodiment of a welding apparatus according to the present invention. The welding apparatus 10 is an automatic TIG welding apparatus, and includes a torch 12 that injects an inert gas to generate a welding arc. The torch 12 is attached to the torch holder 14, and the torch holder 14 is fixed to the slider 16. The slider 16 can move up and down along a vertically extending guide rail 18 by an appropriate drive source (not shown) such as an electric motor.

The torch 12 is attached to an arc-shaped rack 20 provided on the side surface of the torch holder 14 via a mounting bracket 22. The rack 20 is slidable along an arcuate guide 24 provided on the side surface of the torch holder 14. The teeth 26 of the rack 20 mesh with a pinion 28 rotatably supported by the torch holder 14. As shown in FIG. 2, the rotating shaft 3 of the pinion 28
Reference numeral 0 is connected to an electric motor (driving means) 36 fixed to the torch holder 14 via an appropriate reduction / transmission mechanism, a pair of bevel gears 32 and 34 in this embodiment.

In such a structure, when the electric motor 36 is driven, the pinion 28 rotates, the rack 20 slides along the guide 24, and the torch 12 swings in the vertical plane accordingly. In this case, the fulcrum of the swing motion of the torch 12 is set so as to substantially coincide with the arc point A. That is, the torch 12 is positioned so that the axis of the torch 12 always intersects with the central axis of the swing motion of the torch 12, and the intersection is the arc point A of the torch 12. Here, the arc point is a point distant from the tip of the torch by a certain distance in the axial direction, and the point where the welding can be most effectively performed when the object to be welded is arranged at that point. Further, in this embodiment, the swinging motion of the torch 12 is such that the angle of the torch 12 with respect to the horizontal plane, the so-called torch angle is -10 degrees (upward posture indicated by reference numeral 12 'in FIG. 1).
It is designed to be performed within a range of up to +35 degrees (downward posture indicated by reference numeral 12 ″ in FIG. 1).

Further, the welding apparatus 10 of the illustrated embodiment is provided with an arc deflection magnet 38, and its magnetic pole 3
8a and 38b are arranged on the left and right of the tip of the torch 12. When the energization of the arc deflection magnet 38 is controlled, the magnetic field generated between the magnetic poles 38a and 38b changes, and the arc formed on the torch 12 is deflected to the left and right.

Although not shown, the welding apparatus 10 is provided with a wire supply means for supplying the filler wire to the arc point A so that the filler wire can be appropriately supplied during welding.

Using such a welding device 10, LNG
A method of welding the vertical joint portion between the inner tank side plates at the bottom of the tank will be described below.

First, as shown in FIG. 1, the welding device 10 is installed on a tank bottom plate (not shown) and the torch 1 is installed.
Fine adjustment of the position is performed so that the tip of 2 directly faces the vertical joint portion 42 of the inner tank side plate 40 and the arc point A is arranged at a desired position. In order to easily perform this fine adjustment, it is preferable that the slider 16 be movable in the front-rear direction.

Next, the slider 16 is lowered along the guide rail 18 to the lowest position. Then, the electric motor 36 is controlled to oscillate the torch 12, and the tip of the torch 12 is directed obliquely downward so that the arc point A is located at the boundary point between the vertical joint portion 42 and the tank bottom plate. Reference numeral 12 ″ in FIG.
Shows the state of the torch 12 at this time. In this downward position, as will be understood from FIG. 1, the torch holder 14, the slider 16, etc. are above the tip of the torch 12, so when the arc point A is located on the upper surface of the tank bottom plate, the torch holder 14 Does not interfere with the tank bottom plate.

After the installation of the welding device 10 and the alignment of the torch 12 are completed, the electrode 44 of the torch 12 and the side plate 40 are formed.
When a predetermined voltage is applied to the torch 12 and an inert gas is injected from the tip of the torch 12, an arc is generated between the vertical joint portion 42 and the torch 12, and welding is started. After that, the slider 16 is gradually raised along the guide rail 18, and the electric motor 36 is controlled to swing the torch 12 so as to be in the upward posture. And the torch angle is-
The electric motor 36 is stopped at 10 degrees, that is, in the upward posture shown by reference numeral 12 'in FIG. 1, and thereafter the slider 16 is raised in the same manner as in the conventional welding method.
Thereby, the vertical joint portion 42 from the tank bottom plate to the upper end portion
It is possible to continuously and automatically weld the entire area of the above with one welding device 10.

During this welding, the electric motor 3 is moved so as to shift from the downward posture to the upward posture in the shortest possible time.
6 and the drive source of the slider 16 are preferably controlled. Further, when there is a slight positional deviation between the torch 12 and the vertical joint portion 42, the magnetic pole 38 of the magnet 38
By appropriately controlling the magnetic field between a and 38b to deflect the arc, the arc point A can be accurately arranged at a desired position of the vertical joint portion 42.

The preferred embodiment of the present invention has been described above in detail. As the welding apparatus of the present invention, FIGS.
Various configurations other than the one shown in FIG. For example,
Although the above embodiment relates to the TIG welding apparatus, the present invention is also applicable to an apparatus for MIG (metal electrode inert gas) welding.

Further, as shown in FIG. 3, the swing center of the torch may be different from the arc point.
In the welding device 50, the torch 52 is fixed to the sector gear 56 via the mounting bracket 54. The center B of the sector gear 56 is rotatably supported by the torch holder 58. The sector gear 56 meshes with a pinion 60 rotatably supported by the torch holder 58. The pinion 60 is driven by an electric motor 62 via a reduction / transmission mechanism (not shown), so that the fan gear 56 and the torch 52 are integrally rotated or swung in a vertical plane. In the illustrated embodiment, the center of rotation of the fan gear 56 intersects the central axis of the torch 52, and therefore the torch 52 is swung about this intersection B. By thus positioning the swing center B on the torch 52,
The swing radius of the torch 52 is reduced, and the welding device 50 can be downsized.

Further, the torch holder 58 of the welding device 50
Is attached to the slider 66 that moves up and down along the guide rail 64, as in the welding apparatus 10 of the first embodiment. However, in the second embodiment, the torch holder 58 is orthogonal to the front-back direction (the direction in which the guide rail 64 extends and the direction in which the swing shaft of the torch 52 extends) with respect to the slider 66 by a drive source such as an electric motor (not shown). Direction).

When the lower portion of the vertical joint portion of the inner tank side plate is welded using such a welding device 50, the welding is performed while changing the torch 52 from the downward posture to the upward posture, as in the first embodiment. However, since the swing center B of the torch 52 does not coincide with the arc point, when the torch 52 is swung with the torch holder 58 fixed, the arc point moves back and forth in the horizontal direction. Therefore, when welding the vertical joint, the torch 52
It is preferable to move the torch holder 58 in the front-rear direction in conjunction with the swinging of the arc to prevent the arc point from being displaced in the horizontal direction. The other welding procedure is substantially the same as that of the first embodiment, and thus detailed description thereof will be omitted.

[0024]

As described above, the welding apparatus according to the present invention has a relatively simple structure, but when welding side plates of an LNG tank or the like, the vertical joint portion of the bottom side plate is joined. However, automatic welding can be continuously performed from the lower end to the upper end. Therefore, the welded state of the entire vertical joint becomes substantially uniform, and the strength and reliability of the welded portion can be greatly improved.

Since the torch angle can be changed arbitrarily,
It is possible to perform welding work with an appropriate torch angle according to the welding location, working condition, etc., and it is possible to expand the range of application of the welding device.

[Brief description of the drawings]

FIG. 1 is a partial side view showing an embodiment of a welding device according to the present invention.

FIG. 2 is a partial front view of the welding device shown in FIG.

FIG. 3 is a partial side view showing another embodiment of the welding device according to the present invention.

[Explanation of symbols]

10, 50 ... Welding device, 12, 52 ... Torch, 14, 5
8 ... Torch holder, 16, 66 ... Slider, 18, 64
... guide rail, 20 ... rack, 22, 54 ... mounting bracket, 28, 60 ... pinion, 36, 62 ... electric motor, 38 ... arc deflection magnet, 40 ... side plate, 42
... vertical joint portion, 44 ... electrode, 56 ... fan gear.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI technical display location B23K 37/02 B23K 37/02 G (72) Inventor Koji Muramatsu 8-19, Higashisuna, Koto-ku, Tokyo No. 20 Toyo Kanetsu Co., Ltd.

Claims (2)

[Claims] 1. A vertically extending guide rail (18).
A slider (16) that moves up and down along the guide rail (18), and an torch (12) for inert gas arc welding attached to the slider (16) so as to swing in a vertical plane. A welding device provided with a driving means (36) for swinging the torch (12). 2. A welding method for welding a vertical joint portion (42) of steel plates (40) extending in a vertical direction, comprising: a guide rail (18) extending in a vertical direction; and a vertical movement along the guide rail (18). Slider (16)
And a torch (12) for inert gas arc welding attached to the slider (16) so as to swing in a vertical plane, and a drive means (36) for swinging the torch (12). The welding device (10) is arranged adjacent to the vertical joint portion (42), and after welding of the vertical joint portion (42) is started with the tip of the torch (12) being directed obliquely downward, the torch is then opened. The drive means (3) so that the tip of (12) faces upward.
6) to swing the torch (12) and to move the torch (12) upward while maintaining the torch angle after the torch (12) reaches a predetermined torch angle. A welding method characterized in that the slider (16) is moved upward along the guide rail (18).