JPH09122910A - Method for forming projection at insert port of tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily form a projection at the insert port of a tube by performing welding on the outer circumferential groove, depositing molten metal inside this groove and thereby forming penetration in a ring around this groove and the insert port of the tube. SOLUTION: On the outer circumference of the insert port 26 of a tube 25, a ring 27 is mounted which is provided with a fixed thickness in the radius direction and which is formed with an outer circumferential groove 28. Then, welding is performed on the outer circumferential groove 28, depositing molten metal inside this groove 28 to form a molten metal part 32. In addition, a penetration part 34 is formed between the ring 27 around the outer circumferential groove 28 and the insert port 26 of the tube 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a projection of an insertion opening of a pipe formed of a metallic material such as ductile cast iron.

[0002]

2. Description of the Related Art As one type of separation prevention pipe joint, one shown in FIG. 4 is known. That is, while the receiving port 2 is formed at the end of the one duct 1 made of ductile cast iron,
An insertion port 4 is formed at the end of the other pipe 3, and a mortar lining layer 5 is formed on the inner circumference of each pipe 1, 3. Then, as shown in the drawing, by inserting the insertion opening 4 of the other tube 3 into the receiving opening 2 of the one tube 1, these tubes 1 and 3 are joined together.

In detail, a seal material accommodating groove 6 and a lock ring accommodating groove 7 located on the inner side of the seal material accommodating groove 6 are formed on the inner periphery of the receiving port 2. A rubber annular seal material 8 for sealing between the inner peripheral surface of the receiving opening 2 and the outer peripheral surface of the insertion opening 4 is mounted in the sealing material accommodation groove 6. A metal lock ring 9 is mounted in the lock ring receiving groove 7. A centering rubber ring 10 for centering the lock ring 9 is fitted between the outer periphery of the lock ring 9 and the inner periphery of the lock ring housing groove 7.

A lock ring 9 is provided on the outer periphery of the tip of the insertion slot 4.
A protrusion 11 is formed to prevent the insertion port 4 from coming off the receiving port 2 by engaging with the receiving port 2.

In such a structure, with the sealing material 8 and the lock ring 9 mounted in the receiving port 2, the receiving port 2
When the insertion port 4 is inserted into the inside, the protrusion 11 first spreads the sealing material 8 and passes through the inner periphery of the sealing material 8, and
The protrusion 11 similarly spreads the lock ring 9 and passes through the inner circumference of the lock ring 9, whereby the insertion port 4 and the receiving port 2 are joined to each other as shown in the drawing.

Conventionally, the projection 11 of the insertion slot 4 is formed as shown in FIG. That is, as shown in FIG. 3A, first, an annular groove 12 is formed on the outer circumference of the insertion port 4, and the annular groove 12 is formed on the side surface 13 in the pipe radial direction on the tip side and on the side opposite to the tip. And a taper surface 14 formed on. Then, a tight-fitting metal ring 15 having a rectangular cross section and formed in a circumferential direction is fitted into the annular groove 12 from the tip end side of the insertion slot 4.

Next, as shown in FIG.
Weld the part corresponding to 14. 16 is the weld.
In addition, after that, the tip side of the insertion port 4 is welded to the welded portion 17 in a build-up shape.
Weld by. At this time, as shown in the drawing, the spatter 18 often adheres to the outer peripheral surface of the ring 15.

Finally, the protrusion 11 having a predetermined shape as shown in FIG. 3C is shaped by grinder processing or lathe processing. That is, it is necessary to accurately form a corner 19 on the side opposite to the tip of the insertion slot 4 so as to surely engage with the lock ring on the receiving side. In terms of surface, it is necessary to form the surface smoothly so that the sealing material and the lock ring on the receiving side can be spread smoothly and can pass through the inner circumference thereof.
Moreover, in order to smoothly perform the spread, it is necessary to form a taper-shaped surface 21 in the build-up welded portion 17 following the taper surface 20 on the outer periphery of the tip of the insertion opening 4.

[0009]

However, the portion where the welded portions 16 and 17 and the spatter 18 adhere to each other has a high hardness due to the influence of heat during welding, etc. There is a problem that lathe processing involves considerable difficulty.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve such problems and to easily form a protrusion of an insertion opening.

[0011]

In order to achieve this object, according to the present invention, a ring having a constant thickness in the radial direction and having an outer peripheral groove is attached to the outer periphery of an insertion opening of a pipe, and the ring is attached to the outer peripheral groove. Welding is performed to weld the molten metal to the inside of the groove and form a welded portion around the groove between the ring and the insertion opening of the pipe.

With this arrangement, the welded metal portion can be processed easily because only the portion protruding from the ring outer peripheral groove to the outside needs to be processed. The appearance is also beautifully finished. By forming a welded portion at the portion of the ring and the insertion opening of the pipe around the groove, these rings and the insertion opening are welded to each other, so that the other portion, that is, the receiving side that influences the separation prevention performance of the pipe joint No welded metal portion is formed in the engagement portion with the lock ring, so that this portion has a corner from the beginning.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION As shown in FIG. 1 (a), a ring 27 which can be externally fitted to an insertion opening 26 of a duct 25 made of ductile cast iron is prepared. The ring 27 is formed to have an elongated rectangular cross section as shown in the drawing, and is also formed in a circumferentially split annular shape as shown in FIG. As shown, the dividing portion 24 is formed in an oblique direction. As shown in FIG. 1 (b), an outer peripheral groove 28 is formed in the ring 27 at a portion located at a distance from the tip of the insertion opening 26 when the ring 27 is fitted into the insertion opening 26. ing. This outer peripheral groove 28 is
As shown in the figure, the groove bottom portion 29 is formed so that the wall thickness thereof is as thin as possible. Further, in the outer peripheral groove 28, a side portion near the tip of the insertion opening 26 is formed as a side surface 30 in the pipe radial direction, and a side portion away from the tip of the insertion opening 26 is formed as a tapered surface 31. .

As shown in FIG. 1B, the ring 27 is inserted into the insertion opening 26.
When the end is aligned with the tip of the insertion opening, the outer peripheral groove 28 is welded to form the weld metal portion 32 in the groove as shown in FIG. This welded metal portion 32 has an outer peripheral portion.
The groove 33 is formed so as to rise outside the groove 28. Suitable welding for this purpose is MIG welding or electric welding. Then, the melted portion 34 is formed in the portion of the ring 27 around the groove 28. The melt-in portion 34 extends to the insertion opening 26 of the pipe 25 due to the thin wall thickness of the groove bottom portion 29, whereby the ring 27 is fixed to the outer circumference of the insertion opening 26.

Thereafter, as shown in FIG.
The tip end portion of and the corresponding portion of the ring 27 are processed to finish that portion as a predetermined tapered surface 35. Further, the outer peripheral portion 33 protruding from the groove 28 in the welded metal portion 32 is removed.

By doing so, it is sufficient to process only the outer peripheral portion 28 of the deposited metal, and since the deposited metal has a relatively low hardness, the processing is hardly accompanied. It is also easy to make the appearance beautiful. No welded metal portion is formed in the engagement portion 36 with the lock ring on the receiving side, and a predetermined angle can be left in the engagement portion 36 of this barrel from the beginning. Can be easily applied to the pipe joint. As a general rule, it is possible to make the insertion protrusion 37 by the ring 27 already formed at the time of factory shipment by the work in the manufacturing plant, but also when cutting the pipe at the laying site of the pipeline. The projecting portion 37 can be similarly formed at this laying site.

FIG. 3 is a diagram for explaining the welding operation of the ring 27. As shown, a pair of ring pressing rollers 40 and 41 are arranged along the tube axis direction, and the ring pressing rollers 40 and 41 press and hold both ends of the ring 27 along the tube axis direction. That is, each of these ring pressing rollers 40, 41 has large diameter portions 42, 43 and small diameter portions 44, 45, and in the ring pressing roller 41 on the tip side of the insertion opening 26,
The outer peripheral surface of the small diameter portion 45 presses one end of the ring 27 in the pipe radial direction, and the side surface of the large diameter portion 43 makes contact with the end surface of the ring 27 and the tip surface of the insertion port 26, so that the ring 27
Is positioned in the tube axis direction. Similarly, the ring pressing roller 40 on the opposite side presses the other end of the ring 27 in the pipe radial direction by the outer peripheral surface of the small diameter portion 44, and positions the end surface of the ring 27 by the side surface of the large diameter portion 42. The outer peripheral surface of the large-diameter portion 42 is configured not to contact the outer peripheral surface of the insertion opening 26. MI between the ring pressing rollers 40 and 41
A G welding torch 46 is located and used to form the weld metal 32 inside the peripheral groove 28.

With such a structure, during welding,
MIG welding torch 46 while rotating tube 25 around its axis
Are operated to perform welding to form a welded portion 34.
The ring pressing rollers 40, 41 rotate following the rotation of the tube 25 while pressing the ring 27. Then, both ends of the ring are pressed by the ring pressing rollers 40 and 41, so that the ring 27 can be prevented from warping due to welding heat input.

[0019]

As described above, according to the present invention, welding is performed in the outer peripheral groove of the ring having a constant thickness mounted on the outer periphery of the insertion opening of the pipe, and the molten metal is welded inside the groove. A welded portion is formed around the groove between the ring and the insertion opening of the pipe, and this ring is fixed to the outer periphery of the insertion opening. Since it is sufficient to process it, it can be easily processed and the appearance can be finished beautifully. Further, since a welded portion is formed in the portion around the groove between the ring and the insertion opening of the pipe and these rings and the insertion opening are welded to each other, the other portion, that is, the receiving side that influences the separation prevention performance of the pipe joint. No welded metal portion is formed in the engagement portion with the lock ring, and therefore, a corner can be left out from this portion from the beginning. Therefore, the projection of the insertion opening of the pipe can be easily formed.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a method of forming a protrusion of an insertion opening of a tube according to the present invention.

FIG. 2 is a perspective view of the ring in FIG.

FIG. 3 is a diagram for explaining the details of the welding operation shown in FIG.

FIG. 4 is a view showing a cross-sectional structure of a conventional separation prevention pipe joint to which an insertion opening having a protrusion formed by the method of the present invention can be applied.

FIG. 5 is a diagram illustrating a conventional method for forming a protrusion of an insertion opening of a pipe.

[Explanation of symbols]

 25 Pipe 26 Insert 27 Ring 28 Outer peripheral groove 34 Melting part 36 Engagement part 37 Insert protrusion

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location F16L 21/00 F16L 21/00 D // B23K 103: 06

Claims (1)

[Claims] 1. A ring having a constant thickness in the radial direction and having an outer peripheral groove formed therein is attached to the outer periphery of an insertion opening of a pipe, the outer peripheral groove is welded, and molten metal is welded inside the groove. A method for forming a projection of an insertion opening of a pipe, characterized in that a melted portion is formed at a portion of the ring and the insertion opening of the pipe around the groove.