JPH07276094A - How to maintain route intervals for pipe welding - Google Patents

Abstract

(57) [Summary] [Purpose] When arc welding is performed by abutting the edges of pipes, the root interval is kept constant to prevent the occurrence of welding defects and stabilize the welding quality. A flexible sheet-shaped soft magnet, and a T-shaped spacer formed by fixing a horizontal member made of metal and a vertical member made of metal having a thickness equal to a predetermined route interval are prepared. A T-shaped spacer is brought into contact with the edge of the soft magnet and attached by magnetic force to form a root interval holder.
This holder is wound around the first pipe, the second pipe is inserted, the first and second pipes are tack welded together, and after the tack welding, the route interval holder is removed from the pipe. [Effect] It becomes easy to keep the route interval constant, and the welding quality becomes stable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for maintaining a constant route interval for preventing the formation of pits, blow holes, etc. when arc welding is performed by abutting the edges of pipes. The present invention relates to a method for preventing the occurrence of welding defects such as undercut and stabilizing the welding quality.

[0002]

2. Description of the Related Art It is well known that welding defects such as pits and blowholes are generated by gas generated from the root surface during arc welding, and a constant root interval is required during butt welding of pipes. It is important to carry out the welding work while keeping it. Conventionally, this route interval depends on the experience of the welding operator, and methods such as pinching the welding rod are taken on site, but the welding quality varies depending on the skill of the welder and the environmental conditions of the welding site. There was a problem that it appeared.

Japanese Utility Model Laid-Open No. 55-71685 “Route gap setting device for welding groove”, Japanese Utility Model Laid-Open No. 62-128292 “Outer clamp device for piping”, JP-A-4-84.
No. 693, “Filler for adjusting the root gap of welded joints”, in order to maintain the root gap, a method of screwing the top, a method of winding a clamp around the pipe, and an automatic welding wire inserted in the gap part. A method for doing so is disclosed.

However, the method of mounting the top and winding the clamp requires a tool for tightening the screw, and the work of mounting and removing the same is troublesome and takes an extra time, which makes it difficult to carry out. Is. The method of inserting a straight welding wire into the welding gap is suitable for welding flat plates, but since the abutting part of the pipe is circular, there is the drawback that the welding wire will fall off. is there.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for maintaining a predetermined route interval and stabilizing the welding quality during butt welding of pipes.

[0006]

The above-described object of the present invention is to provide a flexible sheet-shaped soft magnet having a linear edge extending in the longitudinal direction, and to horizontally extend the metal horizontally. A plurality of T-shaped spacers, each of which is formed by fixing members and a vertical member made of metal having a thickness equal to a predetermined route interval, are provided, and the T-shaped spacers of the T-shaped spacers are provided on the side of the horizontal member at the straight edges of the soft magnet. The edge gaps are brought into contact with each other and attached by magnetic force, and the T-shaped spacers are attached along the straight edge at substantially constant intervals to form a root interval holder, and each vertical interval of the root interval holder is formed. A soft magnet is wound around the outer periphery of the first pipe while the first side surface of the member is in close contact with the edge of the first pipe,
Is inserted into the space surrounded by each horizontal member of the route interval holder, the end of the second pipe is brought into close contact with the second side surface of each vertical member of the route interval holder, The first pipe and the second pipe are provisionally welded by inserting a welding rod through the circumferential gap, and after the provisional welding, the route interval holder is removed from the pipe to maintain a predetermined route interval. This is achieved by a method for holding a route interval for pipe welding.

[0007]

According to the route interval maintaining method of the present invention based on the above construction, the route interval maintaining tool can be formed by winding the soft magnet around the outer periphery of the first pipe, performing temporary welding, and then separating the soft magnet. Since the work for attaching and detaching is completed, the work for maintaining the route interval can be performed quickly and easily. Therefore, it becomes easy to keep the route interval constant, and the stabilization of the welding quality can be achieved.

As the soft magnet used in the method of the present invention, it is possible to use a so-called sheet-shaped magnet in which a flexible magnet called a rubber magnet or a plastic magnet is formed into a strip shape. This sheet-shaped magnet has a magnetic material dispersed in rubber or plastic and has a smaller magnetic force than a metal magnet, and therefore can be used very suitably for the work of attaching and detaching to the outer circumference of the pipe.

A mixture of fine powder of a magnet in rubber or plastic and molding is also called a composite magnet. As the magnetic material, samarium cobalt, barium ferrite, etc. are known in addition to NdFeB. Hereinafter, the present invention will be described in more detail with reference to the embodiments of the accompanying drawings.

FIG. 1 shows the entire root gap holder used in the root gap holding method of the present invention. The root gap holder 30 is composed of a soft magnet 10 and five T-shaped spacers 20. . The soft magnet 10 is a so-called sheet magnet, and has a linear edge 10A extending in the longitudinal direction, a front end 10B, and a rear end 10C.

In each T-shaped spacer 20, a horizontal member 12 made of a metal plate extending in the horizontal direction and a vertical member 14 made of a metal plate having a thickness equal to a predetermined route interval (for example, 1.6 mm) are spotted. It is formed by being fixed by welding, an adhesive, or another method.

As shown in FIG. 2, if there is a weld overlay on the corner 18 of the intersection of the horizontal member 12 and the vertical member 14, an accurate route interval cannot be maintained.
It is not preferable to weld both by using arc welding. As the dimensions (mm) of each member shown in FIG. 2, for example, a = 75, b = 25, c = 1.6, d = 30, e =
15, f = 50 and g = 15 can be set.

To carry out the method of the present invention, first, as shown in FIG. 1, the soft magnet 10 is placed near the periphery of a wooden table, for example, and the horizontal member of the T-shaped spacer 20 is attached to its linear edge 10A. The side edges of 12 are brought into contact. Both are attached by magnetic force, so 5 T-shaped spacers 2
By attaching 0s at substantially constant intervals, the root interval holder 30 as shown in FIG. 1 can be formed.

After the route interval holder 30 is prepared, the first pipe 80 and the second pipe 90 to be butt-welded are prepared and the work for setting them as shown in FIG. 3 is carried out. First, the first side surface 14A (FIG. 1) of each vertical member 14 of the root interval holder 30 is the edge 80A of the first pipe 80.
The soft magnet 10 to the first
It is wound around the outer circumference of the pipe 80. At this time, it is desirable to set the dimensions so that a slight gap is generated between the front end 10B and the rear end 10C of the soft magnet 10.

A soft magnet 1 wound around the circumference
0 is closely attached to the pipe 80, and the end portion 12A of the horizontal member 12 is
Will project from the first pipe 80 in an overhanging state.

Next, the second pipe 90 is inserted into the space surrounded by the protruding portion 12A of the horizontal member 12. When the end edge 90A of the second pipe 90 comes into contact with the second side surface 14B (FIG. 1) of the vertical member 14, the pipe 80 and 90 cannot be inserted any further, so the pipes 80 and 90 have a predetermined thickness equal to the thickness of the horizontal member 14. It will be positioned at the root spacing and will be better retained by magnetic force.

As is apparent from FIG. 3, since there is a sufficient gap along the circumferential direction between the adjacent horizontal members 12,
By inserting the welding rod through this gap, temporary welding can be performed at three or four places in the circumferential direction.

After the tack welding, if the soft magnet 10 is pulled away from the outer circumference of the first pipe 80, the root gap holder 30 can be easily removed. Thus, a predetermined route interval is maintained between the first pipe 80 and the second pipe 90.

The route interval holder 30 has the advantage that it can flexibly cope with the outer diameter of the pipe because the soft magnet 10 can be wound even when the outer diameter of the pipe increases or decreases.

[0020]

As described in detail above, according to the method of the present invention, the work for attaching and detaching the route interval holder can be performed quickly and easily, and the route interval can be made constant regardless of the skill of the operator. The technical effect is extremely remarkable, such as that it can be maintained and the welding quality is secured and stabilized.

[Brief description of drawings]

FIG. 1 is a perspective view showing the entire root gap holder used in the method of the present invention.

FIG. 2 is a plan view A, a front view B, and a side view C showing details of a root interval holder.

FIG. 3 is a perspective view showing a state in which a route interval holder is attached to the outer circumference of a pipe.

FIG. 4 is a side view showing a state in which a root gap holder is attached on the first pipe.

[Explanation of symbols]

 10 Soft Magnet 10A Straight Edge 12 Horizontal Member 14 Vertical Member 14A, 14B Side Surface 20 T-Shaped Spacer 30 Root Spacing Tool 80 First Pipe 80A Edge 90 Second Pipe 90A Edge

Claims (1)

[Claims] 1. A method for maintaining a predetermined route interval when butt-welding pipes, comprising preparing a flexible sheet-shaped soft magnet having a linear edge extending in the longitudinal direction, and A plurality of T-shaped spacers are prepared by fixing a horizontal member made of metal and a vertical member made of metal having a thickness equal to a predetermined route interval to each other. Each T-shaped spacer is provided on the linear edge of the soft magnet. Abutting the side edges of the horizontal members of the spacers to attach them by magnetic force,
A root spacing holder is formed by adhering each T-shaped spacer along the straight edge at substantially regular intervals, and the first side surface of each vertical member of the root spacing holder is first.
The soft magnet is wound around the outer periphery of the first pipe while being in close contact with the end edge of the pipe, and the second pipe is inserted into the space surrounded by the horizontal members of the root gap retainer. The end edges of the second pipe are brought into close contact with the second side faces of the vertical members of the root-spacing holder, and the welding rod is inserted through the circumferential gap to temporarily connect the first pipe and the second pipe. A method for holding a route interval for pipe welding, characterized in that the route interval holding tool is attached to the pipe after the tack welding and the route interval holder is removed from the pipe after the tack welding.