JPH09184582A - Forming method for projecting part of inserting port of pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily form a projecting part of an insertion port by pressing a ring on the outer periphery of the insertion port of a pipe, performing removing work for the bottom part of an outer peripheral groove, exposing the outer surface of the insertion port of it, pouring deposited metal into the outer peripheral groove, and welding the ring to the insertion port. SOLUTION: A ring 23 provided with the constant thickness in the radial direction and in which an outer peripheral groove 24 is formed is pressed on the outer periphery of an insertion port 22 of a cast iron-made pipe 21, removing work for the bottom part 25 of the outer peripheral groove 24 is performed, and the outer surface of the insertion port 22 of it is exposed. After that, deposited metal is poured into the outer peripheral groove 24 so as to weld the ring 23 to the insertion port 22. After the ring 23 is pressed and fixed on the outer periphery of the insertion port 22 by suitable force, welding work can be easily performed. Since deposited metal is poured into the outer peripheral groove 24 formed by exposing the outer surface of the insertion port 22, the ring 23 can be firmly fixed to the insertion port 22, and therefore, tapering work for the tip of the insertion port 22 can be easily performed.

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 a tube insertion opening.

[0002]

2. Description of the Related Art As one type of pipe joint, there is a slip-on type pipe joint. This slip-on type pipe fitting is configured such that a receiving material and a receiving material can be joined by inserting a sealing material into the receiving material while compressing the sealing material into the receiving material. ing. As a slip-on type pipe joint having a detachment prevention function, a detachment prevention pipe joint having the configuration shown in FIG. 3 has been proposed.

That is, in FIG. 3, a receiving port 2 is formed at one end of one of the cast iron pipes 1 joined to each other.
An annular rubber seal material 4 is arranged in the seal material accommodation groove 3 on the inner circumference of the receiving port 2, and a lock ring accommodation groove 5 is formed on the inner side of the seal material accommodation groove 3. A lock ring 6 which is divided into five in the circumferential direction is attached to the ring 5. Outer peripheral side of lock ring 6 and lock ring receiving groove 5
A holding rubber ring 7 for holding the lock ring 6 in a centered state is arranged between the inner side and the inner circumference side, and the holding rubber ring 7 is bonded to the outer circumference of the lock ring 6.

On the outer periphery of the tip of the insertion port 9 of the other cast iron pipe 8, there is a protrusion capable of engaging with the lock ring 6 from the rear side of the receiving port.
10 are formed. A tapered surface 11 is formed on the outer periphery of the tip of the insertion slot 9 including the protrusion 10 to guide the insertion of the insertion slot 9 into the receiving slot 2 in which the seal material 4 and the lock ring 6 are accommodated. Has been done.

When the protrusion 10 having the tapered surface 11 is formed, a cylindrical ring divided in the circumferential direction on the outer periphery of the insertion slot 9
12 is attached, and this ring 12 is welded and fixed to the insertion slot 9 while being pressed by a pressing roller or the like. Then, after that, both the insertion port 9 and the ring 12 are tapered.

[0006]

However, in such a conventional method of forming a protrusion, there is a problem that the ring 12 needs to be pressed by a pressing roller or the like during welding, which makes the work difficult.

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.

[0008]

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 formed therein is press-fitted into the outer periphery of an insertion opening of a pipe to form the outer peripheral groove. The bottom portion is removed to expose the outer surface of the insertion opening at that portion, and then the weld metal is poured into the outer peripheral groove to weld the ring and the insertion opening.

With this arrangement, the ring is press-fitted onto the outer periphery of the insertion opening of the pipe, so that the ring is fixed to the outer periphery of the insertion opening with an appropriate force. Therefore, welding work can be easily performed without the need for pressing with a pressing roller or the like. Further, since the weld metal is poured into the outer peripheral groove exposing the outer surface of the insertion opening, the ring can be firmly fixed to the insertion opening, and therefore the subsequent taper processing of the tip of the insertion opening can be easily performed.

According to the present invention, the pipe and the ring can be formed of cast iron, and a weld metal containing Ni can be used. That is, when the pipe and the ring are made of cast iron, since they contain a large amount of carbon, it is necessary to prevent cementite from crystallizing in the welded portion. Therefore, by using a weld metal containing Ni, it is possible to prevent such crystallization of cementite.

According to the present invention, the pipe and the ring are made of cast iron, the weld bead of the first layer is formed by using the weld metal containing Ni, and then the mild steel is used thereon. A second layer weld bead can be formed.

In this way, by using the weld metal containing Ni in the weld bead of the first layer,
Similarly, crystallization of cementite can be prevented. Moreover, since the second layer weld bead is formed by using mild steel on it, mild steel has good workability when the weld bead rising outward from the outer peripheral groove is scraped off to be processed smoothly. Because of this, it can be easily processed and finished in a short time.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, when a ring is fitted to the outer periphery of a pipe insertion hole and welded, first, FIG.
As shown in (a), a ring is attached to the outer periphery of the insertion port 22 of the cast iron pipe 21.
Press in 23. The ring 23 is formed of a cast iron cylindrical body having a rectangular cross section as shown in the drawing, and an outer peripheral groove 24 is formed on the outer periphery thereof. The outer peripheral groove 24 is configured so that the thickness of the bottom portion 25 thereof is as thin as possible, and the portion 26 of the ring 23 corresponding to the tip end side of the insertion port is the portion 27 corresponding to the barrel side. It is formed at a position longer than that. A taper surface 28, which serves as a guide when the ring 23 is press-fitted, is formed at the tip of the insertion port 22.

As shown in FIG. 1B, the end surface 29 of the ring 22 is
When the press-fitting has been performed to a position where is aligned with the tip surface 30 of the insertion slot 22, the rotary grindstone 31 is inserted into the outer peripheral groove 24 as shown in FIG. Expose the outer surface. The state at that time is shown in FIG.

Next, while the tube 21 is rotated around the axis, a weld metal is poured into the outer peripheral groove 24 by MIG welding or the like using a wire containing high Ni. FIG. 3E shows the weld bead 32 thus formed. At this time,
High-carbon cast iron of about 3.0 to 3.8% is usually used for the cast iron pipe 21 and the ring 23, so that cementite easily crystallizes in the welded portion. However, by using a wire with a high Ni content as described above, such crystallization of cementite can be prevented. Further, since the weld bead 32 has a raised portion 33 on the outside of the ring 23, the raised portion 33 is scraped off to smooth the outer peripheral surface of the ring 23. Finally, the insertion opening 22 and the ring 23 are both tapered to form a tapered surface 34.

FIG. 2 shows another embodiment according to the present invention. That is, when welding is performed, first, by using a wire containing high Ni, the welding bead of the first layer is welded.
Form 36. Then, next, by welding using a wire made of mild steel, a second-layer welding bead 37 made of mild steel is formed.

In this way, the raised portion 33 is formed of mild steel having good workability, and the raised portion 33 can be easily scraped off. In accordance with this point, it is sufficient to form only the raised portion 33 and the vicinity thereof by the second layer weld bead 37 made of mild steel, and the other portions are as high as Ni-containing first layer weld bead 37. 36 is preferable from the viewpoint of preventing crystallization of the above cementite.

[0018]

As described above, according to the present invention, the ring is press-fitted into the insertion opening of the pipe, the bottom portion of the outer peripheral groove of the ring is removed to expose the outer surface of the insertion opening at that portion, and thereafter, Since the weld metal is poured into the outer peripheral groove to weld the ring and the insertion port, the ring can be fixed to the outer periphery of the insertion port with a proper force by press fitting, and then the welding operation can be easily performed. Further, since the weld metal is poured into the outer peripheral groove exposing the outer surface of the insertion opening, the ring can be firmly fixed to the insertion opening, and therefore the subsequent taper processing of the tip of the insertion opening can be easily performed.

Further, according to the present invention, the tube and the ring are formed of cast iron and the weld metal containing Ni is used, whereby crystallization of cementite during welding can be prevented.

According to the present invention, the pipe and the ring are made of cast iron, the weld metal of Ni is used to form the weld bead of the first layer, and then the mild steel is used to form the weld bead. Since the weld bead of the second layer is formed, not only the crystallization of cementite can be prevented in the weld bead of the first layer as well, but also the weld bead of the second layer is formed by using mild steel. Since it is formed, the weld bead protruding outward from the outer peripheral groove can be easily scraped off in a short time.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an embodiment of the method of the present invention.

FIG. 2 is a diagram illustrating another mode of carrying out the method of the present invention.

FIG. 3 is a diagram illustrating a pipe joint using a pipe with an insertion ring.

[Explanation of symbols]

 21 Cast Iron Pipe 22 Insert 23 Ring 24 Outer Groove 25 Bottom 32 Weld Bead

Claims (3)

[Claims] 1. A ring having a constant thickness in the radial direction and having an outer peripheral groove formed therein is press-fitted into the outer periphery of an insertion opening of a pipe, and the bottom portion of the outer peripheral groove is removed to form an outer surface of the insertion opening. Is exposed, and then a weld metal is poured into the outer peripheral groove to weld the ring and the insertion opening, and a method for forming a projection of the insertion opening of the pipe. 2. The method for forming a protrusion of an insertion opening of a pipe according to claim 1, wherein the pipe and the ring are formed of cast iron and a weld metal containing Ni is used. 3. The pipe and the ring are formed of cast iron, a weld metal of Ni is used to form a weld bead of the first layer, and then mild steel is used to form a weld bead of the second layer. The method for forming a projection of an insertion opening of a pipe according to claim 1, wherein a welding bead is formed.