JPH0751848A - Seam welding device for large-sized steel pipe - Google Patents

Abstract

PURPOSE:To provide a seam welding device for a large-sized steel pipe capable of automatically welding the large-sized steel pipe while rotating the large-sized steel pipe P in order to exactly holding a submerged arc welding machine to the prescribed bottom end by gravity at all times regardless of the size of the large-sized steel pipe. CONSTITUTION:This seam welding machine consists of a cradle 1 which places the large-sized steel pipe P between right and left rollers 11, 11 and rotatably supports the pipe and a holding machine 3 which exists the submerged arc welding machine 5 at all times at the bottom end of the large-sized steel pipe P regardless of rotation of the steel pipe within the large-sized steel pipe P. The holding machine 3 is provided with a supporting rod 15 to be the center of the large-sized steel pipe on a supporting rod 13 which is fixed to the inner peripheral surface of the large-sized steel pipe P and is arranged in the diameter direction of the circle thereof adjustably in position according to the diameter of the large-sized steel pipe. A frame 17 mounted with the submerged arc welding machine 5 at the bottom end is so supported as to be adjustable in height and freely rotatable on the supporting shaft 15. The submerged arc welding machine 5 is held right under the supporting shaft 15 by its supporting form and gravity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for wire-welding a seam along an inner circumference in the production of a large steel pipe.

[0002]

2. Description of the Related Art In the production of large-sized steel pipes, high-quality open hearth steel or electric steel is mass-produced seamlessly by cold drawing or hot drawing when it has a relatively small diameter and is used for many purposes. However, since it is not suitable for such manufacturing especially when the diameter is large, it is manufactured by bending a steel plate to form a short pipe and adding the short pipes.

Conventionally, in such seam welding of short pipes, a worker enters the pipe and works while making full use of welding tools. In that case, when the welding point reaches the upper part, it is difficult to perform the work. Therefore, the welding point is turned downward by rotating the large steel pipe.

[0004]

According to the above-mentioned manual seam welding of large-sized steel pipes, not only is there difficulty and danger in the pipes, but also work is extremely hot especially in summer. In addition, when the large steel pipe is rotated because it is necessary to lower the seam of welding, the work is interrupted, which causes a problem that work efficiency is deteriorated.

In a submerged arc welding machine using wire welding, welding is automatically performed along a seam while running on a rail, but its use is limited when the seam is straight to a flat surface. In the case of large-sized steel pipes, since the joint is circular, it cannot be used especially in relation to the rail. To use a submerged arc welder,
Aligning large and small ring-shaped rails according to the type of pipe diameter is practically impossible from an economical point of view.

The present invention has been made in view of the above circumstances.
We provide a seam welding device for large steel pipes that can automatically weld large steel pipes while rotating, because the submerged arc welder can always accurately hold it at a predetermined lower end by gravity regardless of the size of large steel pipes. It was intended.

[0007]

In order to achieve the above object, a seam welding apparatus for a large steel pipe according to the present invention comprises a pedestal for rotatably supporting the large steel pipe between left and right rollers, and a large support. Inside the shaped steel pipe, it consists of a retainer that constantly positions the submerged arc welder at the lower end of the large steel pipe regardless of the rotation of the large steel pipe. A support rod, which is the center of the large steel pipe, is provided on the support rod arranged in the diametrical direction so that the position can be adjusted according to the diameter of the large steel pipe, and a submerged arc welding machine is mounted on the lower end of the spindle. The frame is supported so that its height is adjustable and can be freely rotated, and the submerged arc welding machine is configured to be held directly below the spindle by its supporting form and gravity.

[0008]

[Operation] Since the seam welding apparatus for large steel pipes is constructed as described above, when operating this, first place the unfinished large steel pipes that need to be welded on the pedestal After the holding machine is set inside, the seam can be welded by the submerged arc welding machine supported by the holding machine while rotating the large steel pipe by the pedestal.

Regarding how to set the holding machine, first,
A supporting rod is diametrically arranged and fixed to one of the inner peripheral surfaces of the large-sized steel pipe, and then the spindle is positioned at the center of the large-sized steel pipe. In this state, even if the large steel pipe rotates, the support shaft is always located in the center thereof, so that the frame supported by the support shaft rotates about the center of the large steel pipe. Therefore, next, the position of the submerged arc welding machine is adjusted by adjusting the height of the frame. Now, mainly because of the gravity of the submerged arc welder, it is located at the lower end of the large steel pipe, so the rotation of the large steel pipe causes the submerged arc welder to run along the circumferential seam at a uniform height. be able to.

[0010]

Embodiments of the present invention will now be described with reference to the drawings.

The seam welding apparatus for large steel pipes comprises a pedestal 1 for large steel pipes P and a holding machine 3 for a submerged arc welder 5 installed inside the large steel pipes P. When the holding machine 3 is installed inside the submerged arc welding machine 5 at a predetermined position, the large steel pipe P is rotated by the pedestal 1 and welding is performed along the joint 7.

The pedestal 1 is provided with a pair of left and right rollers 11 and 11 on a base 9 and is driven by a motor. The rotation of the pedestal 1 and the activation of the submerged arc welding machine 5 are performed by a computer. Controlled by.

The holding machine 3 of the submerged arc welding machine 5 is
The support rod 13, the support shaft 15, the frame 17 and the like are mounted. The support rod 13 is attached, the position of the support shaft 15 is adjusted, the height of the frame 17 is adjusted, and the tip portion 5a of the submerged arc welding machine 5 is fixed. It is set to be operable by adjusting the position.

The support rod 13 includes a base barrel 13a and a front barrel 13.
It is connected by interposing a middle tube 13b between it and c,
The length is adjusted by replacing the middle cylinder 13b. The base cylinder 13a is attached to the inner peripheral surface of the large steel pipe P, and the support shaft 15 is attached to the front cylinder 13c.

A square flange 21 is fixed to the base end of the base cylinder 13a, a convex body 23 is attached to the center of the lower surface of the base cylinder 13a, and through holes 27 for bolts 25 are formed at the four corners of the flange 21. is there. Therefore, when the support rod 13 is attached, the four-piece female screw 29 is attached to the inner peripheral surface of the large steel pipe P.
Is fixed by welding or the like, and the bolt 25 is attached to the flange 2
It is screwed into the female screw 29 from 1 and is tightened with a nut 31 from above the flange 21. Then, the convex body 23 is brought into pressure contact with the inner peripheral surface of the large steel pipe P, and the flange 21 is centered around it.
The support rod 13 is fixed by uniformly tightening.

Even if the inner peripheral surface of the large steel pipe P is a curved surface, the direction of the support rod 13 can be freely adjusted by the point contact by the convex body 23. Therefore, when mounting the support rod 13,
It passes through the center O of the large steel pipe P. In addition, the fixing means of the support rod 13 is not limited to this, and for example, there is also a fixing means that passes over the diameter of the large steel pipe P. In any case, the support shaft 15 can be located at the center O of the large steel pipe P when the support rod 13 is attached in the diametrical direction.

Regarding attachment of the support shaft 15, the front cylinder 13
The slider 25 is fitted in c so that it can move up and down, and the slider 3
The support shaft 15 is connected to 0. A male screw 32 is screwed into the slider 30 to adjust the height,
The slider 30 is moved up and down by rotating the male screw 32 with the handle 34.

At the tip of the support shaft 15, a rotating body 36 having a bearing built therein is axially supported, and the rotating body 36 is supported by the rotating body 36.
7 is mounted so that the height can be adjusted. Therefore, the height of the frame 17 is also adjusted according to the height change of the support rod 13 and the position adjustment of the support shaft 15, so that the submerged arc welding machine 5 is set at an appropriate height position.

The frame 17 includes a pair of left and right vertical bars 33, 3
3 at the lower end, the mounting base 3 of the submerged arc welding machine 5
5 and the fixing member 37 of the rotating body 31 is connected at the upper side, and the height of the frame 17 is adjusted by positioning the fixing member 37. Its structure is omitted in the drawings.

The submerged arc welding machine 5 used was one manufactured by Osaka Electric Co., Ltd. (no rail is required). For this, the length of the arm 39 can be adjusted to adjust the welding tip 5a in the pipe direction of the large-sized steel pipe P. Therefore, the adjustment can also change to the horizontal seam 7.

[0021]

As described above, according to the present invention, there are the following excellent effects.

When a large steel pipe is placed on the pedestal and a holding machine of the submerged arc welding machine is set inside the pedestal, the large steel pipe is rotated by the pedestal and the submerged arc welding machine is moved along the joint by the rotation. Since it can be welded automatically, there is no difficulty and danger of welding in a narrow pipe, and the work efficiency of welding can be improved, which is also suitable for labor saving.

Since it is not necessary to use a rail as a means for arranging the submerged arc welding machine along the seam, the diameter of the large steel pipe can be adjusted by adjusting the position of the support shaft and adjusting the height of the frame. There is no need to prepare a large number according to the above, and it is economically convenient as well as in use.

Since the holding machine and the submerged arc welding machine are set at predetermined positions because the holding machine is integrally provided inside the large steel pipe, the rotation of the large steel pipe causes the submerged arc welding machine to join the joints. Since it follows exactly at even heights, good welding can be performed.

[Brief description of drawings]

FIG. 1 is a front explanatory view showing a usage state of a seam welding apparatus for large steel pipes.

FIG. 2 is an enlarged explanatory view showing a mounting state of the holding machine in the use of the seam welding apparatus for a large-sized steel pipe.

[Explanation of symbols]

 O Center of large steel pipe P Large steel pipe 1 Cradle 3 Holding machine 5 Submerged arc welding machine 11 Roller 13 Support rod 15 Spindle 17 Frame

Claims (1)

[Claims] 1. A pedestal for rotatably supporting a large steel pipe by placing it between left and right rollers, and a submerged arc welding machine is always positioned at the lower end of the large steel pipe regardless of the rotation of the large steel pipe. The holding machine consists of a holding machine, and a supporting rod that is fixed to the inner peripheral surface of the large-sized steel pipe and is arranged in the diameter direction of the circle has a support shaft that serves as the center of the large-sized steel pipe. It is provided so that its position can be adjusted according to the diameter.
The frame on which the submerged arc welder is mounted at the lower end is supported so that its height can be adjusted and can be freely rotated, and the submerged arc welder is held immediately below the spindle by its support form and gravity. A large-sized steel pipe seam welding device having the above-mentioned structure.