JPH03216295A - Backing strip for welding square tube stock - Google Patents

Abstract

PURPOSE:To constantly keep an amount of projection from the edge of a square tube stock and to accurately and easily determine a root gap by dividing a backing metal into eight pieces in total composed of four corner pieces in the peripheral direction and four straight line pieces. CONSTITUTION:The backing strip 1 is composed of four circular-arcuate corner pieces 2 pressed to the inside of each corner part of a square tube stock (a) and four straight line pieces 3 pressed to the inside of each straight line part. In the backing strip 1, first, each corner piece 2 is pressed to the inner peripheral surface of the square pipe stock (a) and each projection 4 is locked to the edge (b) and they are tack-welded. Then, each straight line piece 3 is pressed in from the upper part between the corner pieces 2 at both corners, pressed by each supporting member 5 made of a spring plate to the square pipe (a) and held. Consequently, when the projections 4, 5 are provided on the whole peripheries of the corner pieces 2 and the straight line pieces 3, the gaps generated between the inner surface of the square tube stock (a) and these pieces are filled up and, therefore, very excellent welding can be obtained without falling-in of the bead in a welding time.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The first invention of the present application is to weld an end plate to the edge of a square pipe material by applying it to the entire inner circumference of the end of the square pipe material. The second and third inventions relate to a backing metal for welding that serves as a backing for a bead and makes the root gap constant by protruding a portion of the welding metal. When connecting and welding other square pipe materials, apply it to the entire inner circumference of the ends of both square pipe materials to expose a part of the middle to serve as a backing for the bead and to keep the root gap constant. Regarding backing metal for welding.

BACKGROUND OF THE INVENTION Conventionally, this type of backing metal has been made by bending a band-shaped steel plate to match the inner circumference of a square pipe material.

Problems to be Solved by the Invention However, due to dimensional tolerances, gaps tend to occur between the square pipe material and the backing metal, and the backing metal can be moved inside the square pipe material using a shako vise, hydraulic jig, etc. It was necessary to temporarily weld it while pressing it against the circumferential surface. In addition, when welding an end plate to the edge of a square pipe material, keep the protrusion dimension from the edge constant,
When connecting and welding square pipes, it is necessary to determine the root gap by keeping the distance between both square pipes constant, but since there is no standard for conventional backing metals, it is necessary to use calipers. It is necessary to measure the dimensions and temporarily weld the parts using a similar method, which results in extremely low work efficiency and hinders the automation of work using robot software and the like.

Means for Solving the Problem The invention of the present application was made with the aim of solving this problem, and the first invention is a method for welding an end plate to the edge of a square pipe material. A total of 8 welding backing metals, 4 corner pieces and 4 straight pieces in the circumferential direction, are applied to the entire inner circumference of the end of the material to make a part protrude as backing for the bead. The gist is that the corner piece is divided into pieces, and the corner piece has a protrusion that locks onto the edge of the square pipe material to keep the protrusion dimension constant, and the corner piece has a support part that supports the straight piece. It is something to do.

In addition, the second invention is to weld and connect the end of a square pipe material to another square pipe material having the same cross-sectional shape, by applying it to the entire inner circumference of the end of the double-sided pipe material and welding a part of the middle part. A backing metal for welding is exposed to serve as a backing for the bead.
It is divided into a total of 8 pieces, 4 corner pieces and 4 straight pieces in the circumferential direction, and the corner pieces are fixed to the edges of the double-sided pipe material to maintain a constant spacing between the opposing edges of the double-sided pipe material. The gist is that a protrusion is formed to support the straight piece, and a support portion for supporting the straight piece is formed on the corner piece.

Further, a third invention provides a corner piece of the backing metal for welding according to the second invention, in which a portion of the corner piece to be fitted into one of the double-sided pipe materials is provided with a direction that approaches the center of the square pipe material as it goes toward the tip. The gist is that a guide surface is provided which is inclined and guides the fitting between the corner piece and the one square pipe material.

Functions and Effects The backing metal of the first and second inventions of the present application has the above-mentioned structure, and is divided into a total of 8 pieces, 4 corner pieces and 4 straight pieces in the circumferential direction, so that the dimensions are Even if there is some error, it can be closely attached to the inner circumferential surface of the square pipe material, and
By locking the protrusion formed on the corner piece to the edge of the square pipe material, in the first invention, the amount of protrusion from the edge can be reduced, and in the second invention, the amount of protrusion from the edge of the square pipe material can be reduced, and in the second invention, the protrusion can be adjusted between the edges of the square pipe material. This has the effect of keeping the interval constant, allowing the root gap to be determined accurately and easily, and also enables automatic installation by a robot or the like.

Furthermore, in the third invention, if the corner piece is fixed to one of the square pipe materials in a state in which the guide surface protrudes from the one square pipe material, when the other square pipe material is fitted to the corner piece, Since the guide surface guides the other square pipe material, the effect of easy fitting can be obtained.

EXAMPLES Hereinafter, examples of the first and second inventions of the present application will be described based on the accompanying drawings.

1 to 4 show a first embodiment of the first invention,
The tip of a square pipe material a with an arc-shaped corner is chamfered C leaving an edge b, and a backing metal 1 is fitted to the tip to weld an end plate d. . This backing metal 1 consists of four arc-shaped corner pieces 2 that are applied to the inner surface of the corner portion of the square pipe material a, and four straight linear pieces 3 that are applied to the inner surface of the straight portion. On the outer periphery of 2, a protrusion 4 whose lower surface engages with the edge b of the square pipe material a and forms a certain root cap g (see Fig. 2) between it and the end plate d is formed over the entire circumference of the outer surface. At both ends of the inner periphery, support members 5 made of spring plates have their bases fixed by welding and protrude laterally to form a support section. This support member 5 is used to elastically press the end of the straight piece 3 against the inner surface of the square pipe material a, and is normally used as shown by the solid line in FIG.
It is curved toward the inner surface of the square pipe material a, and, as shown in FIG. ing. A protrusion 6 is formed on the outer surface of the straight piece 3 at the same position as the corner piece 2 over its entire length, the lower surface of which engages with the edge b of the square pipe material a.

This backing metal 1 is attached by first applying the corner piece 2 to the inner circumferential surface of the square pipe material a, locking the protrusion 4 to the edge b, and temporarily welding it. At this time, if matching marks 7 and 8 are attached to the edge b and the corner piece 2, positioning can be easily performed. Next, by pushing the straight piece 3 between the corner pieces 2 of both corners from above, it is pressed against the square pipe material a by the support member 5 made of a spring plate, as shown by the two-dot chain line in FIG. Retained. In this example, since the projection 6 is also formed on the straight piece 3, the height can be determined in the same way as the corner piece by applying it to the edge b. It is also possible to align the height with the corner piece 2 by not providing the corner piece 6 and pressing the end plate d while holding it in a state that projects slightly above the corner piece 2. However, if the projections 4 and 6 are provided all around the corner piece 2 and the straight piece 3 as in this embodiment, the gap created between the inner circumferential surfaces 7 of the square pipe material a will be closed.
There is no bead drop during welding, and better welding can be performed.

In the backing metal 11 of the second embodiment of the first invention shown in Figs. By locking to the edge b of the corner piece 12, the root gap g formed between the lower surface of the end plate d pressed against the protruding end of the corner piece 12 and the edge b is kept constant. ,
Both ends of the corner piece 12 are bent twice at right angles by pressing, and are used as supporting parts 15 that form an insertion gap 16 for the straight piece 13 between the inner peripheral surface of the square pipe material a, and the straight piece 13
By inserting both ends into the insertion gap 16, it is held in close contact with the inner circumferential surface of the square pipe material a, and its upper edge is at the same height as the corner piece 12, so that it is in contact with the end plate d. This ensures that there are no gaps between them. Note that the support portion 15 may be formed by welding a separate steel plate to the inner periphery of the corner piece 12 and protruding upward to form the insertion gap 16.

Figures 8 to 10 show backing money 2 of an embodiment of the second invention.
1 is shown. In this embodiment, the outer periphery of the corner piece 22 has two protrusions 23 on which the lower surface engages the edge b of the lower square pipe material a, and the upper surface engages with the edge b of the upper square pipe material a. One protrusion 24 is formed, and the distance between the lower surface of the lower protrusion 23 and the upper surface of the upper protrusion 24 is a root gap g. Step portions 2 are provided at both ends of the corner piece 22.
7 is formed, and a support member 2 made of steel plate is formed from the inner surface of the lower part.
5 is a supporting portion that projects upward to form an insertion gap 28 for a straight piece 29 between it and the inner circumferential surface of the square pipe material a,
Its tip is curved inward to facilitate insertion of the straight piece 29. Further, a guide portion 26 is formed in the upper part of the corner piece 22 and has a guide surface 30 that is inclined in a direction approaching the center of the square pipe material a toward the upper end, into which the upper square pipe material a is inserted. It's easier to do. In this embodiment, the corner piece 22 is attached by locking the lower protrusion 23 to the edge b of the lower square pipe material a, and is temporarily welded. In this case, if a mark for the protrusion 23 is made on the edge b of the square pipe material a using an appropriate jig, the corner piece 22 can be easily positioned. Next, the straight piece 29 is inserted into the insertion gap 2 of the corner piece 22 with both ends thereof.
8, and then fit the upper square pipe material a along the guide surface 30 of the corner piece 22, and its end edge b.
By abutting against the upper protrusion 24 of the corner piece 22, an accurate root gap g is formed between the edge b of the double-sided pipe material a. In this embodiment, instead of the support part formed by the support member 25, a support part integrally formed by press molding of the corner piece 22 may be provided. You can do it like this. Furthermore, it is also possible to form a protrusion on the straight piece 29 that contacts the edge of the double-sided pipe material.
2 and the straight piece 29 may be formed continuously over the entire circumference, or one protrusion may be formed with two locking surfaces that respectively lock on the edges of the double-sided pipe material.

In addition, various modifications may be made based on the knowledge of those skilled in the art, although no examples will be given one by one. The invention can be practiced in modified forms.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view of the first embodiment of the first invention, Fig. 2 is an enlarged sectional view of a part thereof, Fig. 3 is a plan view of the corner piece, and Fig. 4 is A of Fig. 3. -A sectional view, FIG. 5 is a plan view of a part of the second embodiment of the first invention, FIG. 6 is a longitudinal sectional view, FIG. 7 is a perspective view of a corner piece thereof, and FIG. 8 is a partial plan view of the second embodiment of the first invention. FIG. 9 is a perspective view of the corner piece, and FIG. 10 is a front view of the corner piece. 1, 11, 21: Backing metal 2. 12. 22: Corner piece 3, 13, 29: Straight piece 5.25: Support member 4, 6.
14, 23, 24: Protrusion 15: Support part 30: Guide surface a: Square pipe material d: End plate

Claims (3)

[Claims] (1) When welding an end plate to the edge of a square pipe material, a welding backing plate is used as a backing for the bead by applying it to the entire inner circumference of the end of the square pipe material and making a part protrude. There it is,
Divided into a total of 8 pieces, 4 corner pieces and 4 straight pieces in the circumferential direction, and forming protrusions on the corner pieces that lock onto the edges of the square pipe material to keep the protrusion dimension constant. ,
A backing metal for welding a square pipe material, characterized in that a support part for supporting the straight piece is formed in the corner piece. (2) When welding and connecting the end of a square pipe to another square pipe with the same cross-sectional shape, by applying it to the entire inner circumference of the end of the square pipe to expose a part of the middle. A backing metal for welding used as a backing for a bead, which is divided into a total of 8 pieces, 4 corner pieces and 4 straight pieces in the circumferential direction, and is attached to the corner pieces and to the edge of the double-sided pipe material. A rectangular pipe material characterized in that a protrusion is formed to lock and maintain a constant spacing between the opposing edges of the square pipe material, and a support part for supporting the straight piece is formed in a corner piece of the square pipe material. Backing metal for welding. (3) A portion of the corner piece that fits into one of the square pipe materials is inclined in a direction that approaches the center of the square pipe material as it goes toward the tip, so that the corner piece and the one square pipe material fit together. 3. The welding backing metal according to claim 2, further comprising a guide surface for guiding the welding.