JPH0647179B2 - Method for manufacturing dissimilar metal pipe fittings - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of use) The present invention relates to metal pipes of different materials, for example, titanium pipes and copper pipes, or stainless steel pipes and titanium pipes. The present invention relates to a method for manufacturing a pipe joint.

(Prior Art) Various kinds of metal pipes such as stainless steel pipes, titanium pipes, and aluminum pipes are used in various plants in consideration of applications and environments. Therefore, in these plants, metal pipes of different materials (dissimilar metal pipes) may have to be joined. It is advantageous to join the metal pipes by welding, which has excellent work efficiency and is inexpensive. However, welding may not be possible depending on the materials of both metal pipes to be connected.

In welding, dissimilar metal pipes such as steel pipes and stainless steel pipes can be connected, but if dissimilar metal pipes such as titanium pipes and copper pipes or stainless steel pipes and titanium pipes are used, it is extremely difficult to weld them. Since brittle intermetallic compounds are generated in the connection, it is impossible to connect. In the case of titanium pipe and copper pipe, Ti ₂ Cu, TiCu ₃
For stainless steel pipe and titanium pipe, Ti ₂ Ni, TiNi ₃ ,
Intermetallic compounds such as

Therefore, in the case of a dissimilar metal pipe that cannot be connected by such welding, the following method has been conventionally used.

For example, as shown in FIG. 8, a donut-shaped disc (20) made of the same material as the metal pipe A (for example, titanium pipe) is provided at the end on the joining side, while a metal pipe B (for example, copper pipe) is provided. A so-called flange that connects donut-shaped discs (21) made of the same material as these to the ends and fits them by welding, and then fastens the discs (20) and (21) together with bolts (22). This is a method of using a mold joint (23). However, in the flange type joint, since the joint portion is larger than the outer diameter of the pipe to be connected, there is a disadvantage that it becomes a hindrance during pipe construction and restricts the piping design. Further, there is a drawback that the reliability of the sealing property of the joint is low.

Further, as another connection method, there is a so-called friction welding method in which end faces of different metal pipes are brought together and the pipes are rotated and joined while applying pressure. This method does not cause the joint to become larger than the outer diameter of the pipe as in the flange type joint, but has a drawback that the reliability of the seal at the joint is low. Furthermore, in friction welding, since the joint surface is perpendicular to the pipe axis, the joint area must be about the same as the cross section of the pipe material to be joined, and therefore the joint strength is limited.

By the way, as a method capable of eliminating the drawbacks in the flange type joint and the friction welding, a pipe (24) made of the same material as the dissimilar metal pipes A and B as shown in FIG. 25), (For example, if the metal tube A is titanium, (24) is a titanium tube, and if the metal tube B is a copper tube, (25) is a copper tube)
There is a method in which a metal joining joint (26) made by joining the two is interposed between the metal pipes A and B, and their ends are welded (27) to be connected. According to this method, since the same kind of metal is used for welding, no intermetallic compound is generated in the welded portion. Further, the joint does not become larger than the outer diameter of the pipe, and the reliability of the sealing property is high.

Then, a method of manufacturing such a metal joint, that is, a dissimilar metal pipe joint by utilizing a hot isostatic pressing method has been proposed (Japanese Patent Laid-Open No. 61-52996). However, the hot isostatic pressing method has the drawbacks of low productivity and high joint cost.

As described above, the conventional connection method has a problem in the sealing property of the joint portion or the productivity of the joint. Further, the dissimilar metal pipes are not necessarily connected to each other with the same inner and outer diameters as shown in FIGS. 8 and 9. In some cases, it is necessary to connect dissimilar metal pipes having different inner and outer diameters. Even in such a case, it is advantageous to use a dissimilar metal pipe joint that has a high sealing property at the joint and does not generate an intermetallic compound by welding. That is, the inner and outer diameters on one end side of the joint are the same as the inner and outer diameters of one of the dissimilar metal pipes to be connected, and the inner and outer diameters on the other end side of the joint are inside the other metal pipe. -It is recommended to use a different-diameter dissimilar metal pipe fitting with the same outer diameter. However, it is difficult to inexpensively manufacture a different diameter type dissimilar metal pipe joint by a conventional manufacturing method such as a frictional pressure hot isostatic pressing method.

(Problem to be Solved by the Invention) An object of the present invention is a joint capable of connecting dissimilar metal pipes having the same inner / outer diameter or dissimilar metal pipes having different inner / outer diameters by welding. One end side has the same material and the same inner / outer diameter as the one dissimilar metal tube to be connected, and the other end side of the joint has the same material and the same inner / outer diameter as the other dissimilar metal tube. Another object of the present invention is to provide a method for inexpensively and efficiently manufacturing a dissimilar metal pipe joint having high sealing reliability, a large joint area, and excellent joint strength.

(Means for Solving the Problems) The gist of the present invention resides in the following joint manufacturing method.

Expand or reduce the diameter from one end of the double-clad rod to a different-diameter double-clad rod. Then, on the large-diameter side of this different-diameter double-clad rod, use the inner layer material and the small-diameter side. Manufacture of dissimilar metal pipe joints characterized by inner / outer cutting so that the outer layer material remains, or inner / outer cutting so that the outer layer material remains on the large diameter side and the inner layer material remains on the small diameter side Method.

(Operation) Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a diagram showing the main manufacturing steps of the method of the present invention.

The double clad rod, which is a raw material, can be manufactured by a hot drawing method such as a hot extrusion method, a bombardment method or a diffusion annealing method.

The double clad rod is made of the same material as either one of the dissimilar metal tubes to be connected to the inner layer material and the same material as the other metal tube of the outer layer material. That is, when one of the dissimilar metal pipes to be connected is, for example, a titanium pipe and the other is a copper pipe, a double clad rod in which the inner layer material is titanium and the outer layer material is copper, or the inner layer material is copper and the outer layer material is titanium is there.

Next, the double clad rod made of this material is cut into a predetermined length, and the diameter-expanding process or the diameter-reducing process is performed from one end to an arbitrary position. For example, as shown in Fig. 2 (a), the diameter expansion process is performed by inserting the wedge-shaped plug (4) inside the double clad rod (3) consisting of the inner layer material (1) and the outer layer material (2). It can be done by pushing in.

On the other hand, the diameter reducing process can be performed by pushing the double clad rod (3) halfway into the die (5) as shown in FIG.

After expanding or reducing the diameter, the specified parts of the inner and outer layer materials are machined and removed, and one end side is the inner layer material and the other end side is the outer layer material. A straight pipe type dissimilar metal pipe joint having the same or a different diameter type dissimilar metal pipe joint having different inner and outer diameters from the central portion of the joint.

The diameter expansion processing and the diameter reduction processing may be performed cold, but it is preferable to perform hot processing for materials that are difficult to process in cold, such as stainless steel and titanium alloy.

In this way, using a long double-clad rod as a material and performing sequential processing in the above steps, an inexpensive straight pipe type dissimilar metal pipe joint or different diameter type dissimilar metal pipe joint with excellent joint strength can be obtained. It can be manufactured efficiently.

Next, a method of manufacturing a dissimilar metal pipe joint from a double clad rod will be specifically described along with the above-mentioned steps, divided into a case of diameter expansion processing and a case of diameter reduction processing.

First, FIG. 3 is a cross-sectional view showing an example of the shape of the work material in each step in the case of manufacturing a dissimilar metal pipe joint after expanding the diameter of the double clad rod. Inner layer material (1) (core material)
Double clad rod (3) consisting of the outer layer material (2) (Fig. 3)
(a)) is expanded from one end thereof to an arbitrary position to form a different diameter double clad rod (6) (Fig. 3 (b)).

When manufacturing a straight pipe type dissimilar metal pipe joint from this double clad rod, one end side (expansion side) as shown in the same figure (b)
The outer diameter d ₇ of the inner layer material (1) is substantially the same as the outer diameter d ₆ of the outer layer material (2) on the other end side (the original side which has not been expanded). It is better to process it. This may be done when manufacturing a different-diameter type dissimilar metal pipe joint,
Alternatively Figure 4 one end side as shown in (a) (enlarged side) inner layer member (1) the outer layer member having an outer diameter d ₈ the other end (the side of the intact not subjected to diameter) of the ( It may be larger than the outer diameter d _{6 of} 2).

Next, the different diameter double clad rod (6) is machined. In machining, a straight pipe type dissimilar metal pipe joint or a dissimilar diameter type dissimilar metal pipe joint can be obtained by appropriately selecting a portion to be cut. That is, as shown in (a) of FIG. 3 (c), at least the outer layer material (2) on the large diameter portion side is removed by cutting to eliminate the stepped shape in the axial direction, and the inner layer material (1) is enlarged. If the outer peripheral layer (10) is removed by cutting on the radial side, it has a joint part (7) at the center as shown in (a) of FIG. 3 (d), and one end side of the joint is the inner layer. Of both ends of the material (1), the other end of which is the outer layer material (2)
A straight pipe type dissimilar metal pipe joint (8) having the same outer diameter can be obtained.

As shown in Fig. 3 (c) (b), unnecessary outer layer material on the small diameter side
If (2) is removed by cutting and the inner layer material (1) is removed by leaving the outer peripheral layer (10) on the side of this small diameter, it will be joined to the central part as shown in (b) of FIG. It is possible to obtain a different diameter type dissimilar metal pipe joint (9) having the portion (7), in which the small diameter portion side of the joint is the inner layer material (1) and the large diameter portion side is the outer layer material (2). Alternatively, as shown in FIG. 4 (a), the outer layer material (2) on the large diameter side is removed by cutting and the inner layer material is removed.
If (1) is removed by cutting while leaving the outer peripheral layer (10) on the large diameter side, the small diameter side opposite to the different diameter type joint is the outer layer material (2) and the large diameter side is the inner layer material (1). It is also possible to obtain a different diameter type dissimilar metal pipe joint (9) having a joint part (7) in the center part consisting of (4).

On the other hand, also in the case of manufacturing the dissimilar metal pipe joint after reducing the diameter of the double clad rod, it can be carried out by a method substantially similar to the above.

FIG. 5 is a cross-sectional view showing an example of the shape of a work material in each step in the case of manufacturing a dissimilar metal pipe joint after reducing the diameter of the double clad rod.

The double clad rod (3) (FIG. 5 (a)) is reduced in diameter from one end side to an arbitrary position to form a different diameter double clad rod (6) (FIG. 5 (b)).

When manufacturing straight pipe type dissimilar metal pipe joints from double-clad rods with different diameters during diameter reduction processing, the outer layer material (2) on the one end side (reduction side) is It is preferable that the diameter d ₉ is approximately the same as the outer diameter d ₈ of the inner layer material (1) on the other end side (the original side that has not been reduced in diameter). When manufacturing a metal pipe joint, this may be done, or as shown in FIG. 6 (a), the outer diameter d ₁₀ of the outer layer material (2) on one end side (reduced diameter side) may be changed to the other end side. It may be smaller than the outer diameter d ₈ of the inner layer material (1) which has not been reduced in its original size.

Next, as shown in (a) of FIG. 5 (c), at least the outer layer material (2) on the large diameter side is removed by cutting to eliminate the axial stepped shape, and the inner layer material (1) is removed. If the outer peripheral layer (10) is removed by cutting on the large diameter side, the joint (7) is formed at the center as shown in Fig. 5 (d) (a), and one end of the joint is the inner layer. A dissimilar metal pipe joint (8) having the same inner and outer diameters at both ends of the material (1), the other end of which is the outer layer material (2), can be obtained.

As shown in (b) of FIG. 5 (c), the outer layer material (2) on the small diameter portion side is cut and removed, and the inner layer material (1) is formed on the small diameter portion side and the outer peripheral layer (10).
If it is removed by cutting, the joint part (7) is located in the center as shown in (b) of Fig. (D), the small diameter side of the joint is the inner layer material (1) and the large diameter side is the outer layer material. Different diameter type dissimilar metal pipe joint consisting of (2)
(9) can be obtained. Alternatively, as shown in FIG. 6 (b), the outer layer material (2) on the large diameter portion side is cut and removed, and the inner layer material (1) is removed on the large diameter portion side while leaving the outer peripheral layer (10). For example, on the opposite side to the above, the small diameter side of the joint is the outer layer material (2), the large diameter side is the inner layer material (1), and the different diameter dissimilar metal pipe joint (9) has the joint part (7) in the center part. ) Can also be obtained.

FIG. 7 (a) shows different metal pipes A and B having the same inner and outer diameters using a straight pipe type dissimilar metal pipe joint (8) manufactured by the method of the present invention, and FIG. FIG. 3 is a schematic view when different diameter metal pipes A and B having different inner and outer diameters are connected by welding using a diameter type different metal pipe joint (9). Different Metal Pipe Fittings (8)
In (9) and (9), the same material is used on the metal pipe A side and the same material on the metal pipe B side, so that no brittle intermetallic compound is generated in the welded portion (11). Further, since the joint has the same inner and outer diameters as those of the metals to be connected, there is no problem that the connecting portion becomes unnecessarily large unlike the flange type joint.

Depending on the liquid flowing in the pipe, the corrosion resistance of the diffusion layer at the joint interface of the dissimilar metal pipe joint may become a problem. In such a case, when a double clad rod made of a material is manufactured, if a suitable intermediate material is interposed between the inner layer material and the outer layer material, a diffusion layer having excellent corrosion resistance is formed at the joint interface. be able to.

The dissimilar metal pipe joint manufactured by the method of the present invention is excellent in joint strength because the joint interface between dissimilar metals constituting the joint is much longer than that of the conventional friction welding. The joint interface can be made to have any length by changing the expansion or contraction angle of the plug or die, so that the length can be freely selected according to the strength required for design. it can. Of course, it goes without saying that the metal tubes to be combined may be of any kind.

The present invention will be further described with reference to examples.

(Example 1) Using an inclined rolling mill having three cone type rolls, an outer layer material of titanium (outer diameter: 40 mm, wall thickness: 5 mm) and a solid inner layer material of copper (diameter: 30 mm) were used. Made of titanium clad copper rod,
Outer layer material of stainless steel (outer diameter: 40 mm, wall thickness: 3 mm),
A stainless clad aluminum rod made of a solid aluminum inner layer material (diameter: 34 mm) was manufactured.

In addition, titanium and copper are pure titanium (JIS H 46302 type) and oxygen-free copper (JIS H 3300 (1020)), stainless steel is JIS SUS 30.
JIS L 4040 1070 was used for 4 L and aluminum.

After cutting this to 100 mm length, after heating it to 600 ℃ for titanium clad copper rod and 500 ℃ for stainless clad aluminum rod, 40 mm from one end was subjected to diameter reduction processing with a die to the following sizes, respectively. .

(1) Different diameter titanium clad copper rod after diameter reduction One end side (reduction diameter side) Outer layer material outer diameter 30 mm, inner layer material diameter 19.5 mm Other end side (non-reduction diameter side) Outer layer material outer diameter 40 mm, inner layer Material diameter 30 mm (2) Different diameter stainless clad aluminum rod after diameter reduction One end side (reduced diameter side) Outer layer material outer diameter 34 mm, Inner layer material diameter 27.5 mm Other end side (non-reduced diameter side) Outer layer material outer diameter Diameter 40mm, diameter 34mm of inner layer material Next, as shown in (a) of Fig. 5 (c), the outer layer material on the large diameter side is removed by cutting the expanded copper alloy rod of different diameter in (1) above. To eliminate the stepped shape, and to remove the inner layer material by cutting away the outer layer on the large diameter side, leaving pure titanium on one end and oxygen-free copper on the other end and an outer diameter with a joint in the center. 29mm x inner diameter 23
We made a straight pipe type dissimilar metal pipe joint with a thickness of 3 mm and a wall thickness of 3 mm. Further, as shown in (b) of FIG. 5 (c), the outer layer material on the small diameter portion side is removed by cutting, and the inner layer material is removed on the small diameter portion side while leaving the outer peripheral layer. Pure titanium outer diameter 39 mm × inner diameter 33
mm × Thickness 3mm, Oxygen-free copper on the small diameter side, outer diameter 19mm × inner diameter 13
mm diameter x 3 mm thickness, a different diameter type dissimilar metal pipe joint having a joint in the center was manufactured.

On the other hand, the different diameter stainless clad aluminum rod after the diameter reduction of (2) is machined in the same manner, and one end side is stainless steel and the other end side is aluminum and the outer diameter is 33 mm and the inner diameter is 29 mm. × Straight pipe type dissimilar metal pipe fitting with a wall thickness of 2 mm and stainless steel on the large diameter side of the fitting, outer diameter 39 mm × inner diameter
35mm x 2mm thick, aluminum on the small diameter side is 27mm x outer diameter
We made a different diameter type dissimilar metal pipe joint with an inner diameter of 23 mm x wall thickness of 2 mm and a joint in the center.

Penetration testing and tensile testing were conducted on the manufactured dissimilar metal pipe joints. As a result, no defects were found in the joint portion, and the fracture position was the base metal portion.

(Effects of the Invention) As described above, according to the method of the present invention, a dissimilar metal pipe joint having excellent joint strength and having the same inner and outer diameters at both ends and a dissimilar metal pipe having different inner and outer diameters at both ends The joint can be manufactured efficiently and inexpensively.

[Brief description of drawings]

FIG. 1 is a diagram showing the main manufacturing steps of the method of the present invention, FIG. 2 is a schematic diagram showing an example of diameter expansion processing and diameter reduction processing, and FIG. 3 is a double clad rod manufactured by the method of the present invention. The figure which shows an example of the shape of the to-be-processed material in each process at the time of manufacturing a dissimilar metal pipe joint after diameter-expanding processing, FIG. 4 is a figure which shows another example of machining, FIG. 5 is this invention. The figure which shows an example of the shape of the to-be-processed material in each process at the time of manufacturing a dissimilar metal pipe joint after carrying out the diameter reduction processing of the double clad rod by the method, FIG. 6 is a figure which shows another machining example, FIG. 7 is a schematic diagram showing a method for connecting dissimilar metal pipes using the dissimilar metal pipe joint produced by the method of the present invention, and FIG. 8 is a method for connecting dissimilar metal pipes using a conventional flange type joint. Fig. 9 is a schematic diagram showing the connection of dissimilar metal pipes using a conventional dissimilar metal pipe joint. Schematic diagram showing that the method is. (1) …… Inner layer material (2) …… Outer layer material (3) …… Double clad rod (4) …… Plug (5) …… Die (6) …… Differential diameter double clad rod (7)… … Joined portion (8) …… Straight pipe type dissimilar metal pipe fitting (9) …… Different diameter type dissimilar metal pipe joint (10) …… Outer layer (11) …… Welded part (20) …… Metal A Donut disk (21) …… Metal B donut disk (22) …… Bolt (23) …… Flange type joint (24) …… Metal tube A (25) …… Metal tube B ( 26) …… Metal bonded joint (27) …… End weld.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kyoji Nakao 1-1, Fuso-cho, Amagasaki-shi, Hyogo Sumikin Kiko Co., Ltd. (56) Reference JP-A 64-71582 (JP, A) JP A 57-159281 (JP, A) JP 60-45991 (JP, B2)

Claims (1)

[Claims] 1. A double-clad rod having a different diameter from one end of the double-clad rod to a desired position by expanding or reducing the diameter to obtain a different-diameter double-clad rod. Internal / external machining is performed so that the outer layer material remains on the small diameter side, or the inner layer material remains on the large diameter side and inner layer material remains on the small diameter side.
A method for manufacturing a dissimilar metal pipe joint, characterized by external machining.