JPH0245955B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a pipe joint that joins pipes made of different materials depending on the part used when transferring high-temperature fluids or extremely low-temperature fluids. The present invention relates to a method for manufacturing into.

<Prior art> For example, in some types of fluid transfer pipes, it is necessary to use pipes made of materials with good thermal conductivity due to the need for heat exchange in some parts, while in other parts it is necessary to use pipes made of materials with good thermal conductivity. On the contrary, there are many cases where materials with poor thermal conductivity, strength, and corrosion resistance are required. Since the welding strength of dissimilar metals is weak or there are many combinations that are impossible, in order to join such dissimilar metal pipes together, pipe joints are used, in which both sides are made of different materials. It is necessary to use pipe joints made of the same type of material as the pipes to be joined to each other.

Conventionally, as shown in Fig. 5, for example, a type of pipe a and a different type of metal pipe b are joined only at their butt end faces, and the manufacturing method is as follows. As shown in Figure 6, metal block a and metal block b are joined by some means such as explosive bonding or crimping, and the sixth
The pipe joint was created by cutting off the pipe from the points shown in the figure, such as lines A ₁ - _{A 1} and A ₂ - A ₂ , and then cutting off the unnecessary parts by cutting or other machining processes, as shown in Figure 2. However, first of all, it is difficult to obtain a bonded body with a high bonding strength between metal block a and metal block b as shown in FIG.
In addition to the manufacturing disadvantages of being complicated to manufacture, the resulting pipe joint has different metals joined only at their butt end faces, resulting in insufficient joint area and bending stress, etc. The disadvantage was that the reliability of the sealing accuracy was poor.

<Problems to be Solved by the Invention and Means Therefor> The present invention solves the above-mentioned drawbacks, widens the bonding area at the boundary between dissimilar metals, improves the bonding strength, and makes it possible to solve the problems of various types of metals. Even comrades
It is also an object of the present invention to provide a method for manufacturing pipe joints that can be manufactured even with small diameters and thin walls.
The gist is to butt solid bodies or hollow bodies of different metals together, surround the outer periphery with metal pipes,
If the metal bodies that have been butted together are hollow bodies, insert the required core into the hollow part, seal the periphery in a vacuum state by welding or other means, and then apply hot isostatic pressure. The butted dissimilar metals and the outer metal pipe are metallurgically joined together, and the unnecessary parts are then cut off by cutting or other means.

Here, the vacuuming and sealing performed prior to hot isostatic pressure treatment can be solved at the same time by using a method of welding in a vacuum, such as electron beam welding, but this is not limited to sealing with the outside. The method and means are not particularly limited as long as the interior is kept in a vacuum.

In the present invention, the term "metal" includes not only pure metals but also so-called alloys, and also includes cases where any one of them is a composite metal, such as a double pipe.

<Action of the present invention> In the present invention, as shown in FIG. Since it is metallurgically joined, the joint strength of the joint is high from both a structural and chemical standpoint, and it can be widely applied to high-pressure or high-vacuum piping.

In the present invention, in addition to the structure shown in FIG. 1, there are also structures shown in FIGS. 2 to 4, and the point is that the bonding surfaces of dissimilar metals need only be bonded in an overlapping manner.

As the dissimilar metals of the present invention, that is, metal A and metal B, for example, stainless steel with excellent strength and corrosion resistance is selected as metal A, and copper or copper alloy with high thermal conductivity is selected as metal B, The material for pipes made of metal C is usually the same material as metal B, but for example, when metal B is copper, an alloy of copper and nickel may be used, containing an appropriate amount of nickel. There are cases where copper alloys are used to improve mechanical strength.

Furthermore, when joining stainless steel and copper (alloy), it goes without saying that nickel may be interposed at the boundary in the form of plating or plating to improve the joining strength between the two.

In the case of the present invention, since hot isostatic pressing treatment at high temperature and high pressure is used for manufacturing, a fairly wide range of combinations of metals A and B are possible. There are stainless steel-copper, copper-aluminum, stainless steel-titanium, stainless steel-cypronickel, etc.

The manufacturing method of the present invention will be described in detail below with reference to the drawings.

In Fig. 7A, a solid body 5 made of metal A and a solid body 6 made of metal B are surrounded by a pipe 7 made of metal B, and after the inside of the pipe 7 is evacuated, both the pipe 7 and the solid body 6 are surrounded. It is a diagram in which the boundary portions exposed to the outside of the solid bodies 5 and 6 are sealed and welded 8.

In this case, if the pipe 7 and either the solid body 5 or 6 are made of materials that are difficult to weld, an end plate as shown by 9 in FIG. 7 should be brought into contact with the end plate 9 and the pipe. 7 may be welded, or other welding methods may be employed, such as crimping or welding with the end face of the pipe 7 crushed (the same applies hereinafter). The thus treated material is subjected to hot isostatic pressure treatment in a high-temperature, high-pressure container to join the two solid bodies 5 and 6 and the pipe 7 together metallurgically, and then both the solid bodies 5 and 6 The core of the solid body 5 made of metal A is cut off and removed in the longitudinal direction, leaving only the outer periphery with the required thickness, and the pipe 7 made of metal B is shaved off over a certain length from the free end side of the solid body 5 made of metal A. Metal A
By exposing the pipe joint shown in FIG. 7B, a pipe joint is obtained. In the diagram shown in FIG. 7B, a portion of the pipe 7 on the right side of the diagram is also cut away over a certain width to form a pipe joint shape.

In this case, the material of the pipe 7 is a metal C that is different from the metal B, for example, if the metal B is copper, the metal C
If a material such as Cypronickel is used as the material, the metal C will be present only in the portion raised on the outer periphery as shown in FIG. 7B, making it possible to increase the mechanical strength of the pipe joint itself.

Next, as shown in Fig. 8, a hollow body 5' made of metal A and a hollow body 6' made of metal B are butted together, and the outer periphery of the hollow body 5' is made of metal C (this may be the same type as metal B).
A core 10 is placed in the inner space of both hollow bodies 5' and 6', and the outer periphery is sealed in the same manner as described in the case of FIG. If 10 is metal, seal welding can be performed as is, but if a non-metallic body such as ceramic is used as the core, end plates 9 made of a metal that can be easily welded to pipe 7 of metal C are attached to both end faces. After applying it to both end faces, it shall be sealed. Although FIG. 8 shows a case where the core is a solid body, the same process can be performed when the core 9 is a hollow body as shown in FIG.

Next, FIG. 10 shows a state in which the hollow body 6' made of metal B in FIG. 5 is absent, and that part becomes a space. When subjected to hot isostatic pressure treatment at high temperature and high pressure, the pipe 7 made of metal B and, if the core 10 is made of metal, the core 10 made of metal B also enter into the space, Since the space is filled, if unnecessary parts are removed after hot isostatic pressure treatment, a pipe joint as shown in FIG. 7B and FIG. 1 can be obtained.

In addition, in the method of providing a space between the outermost pipe 7 and the core 10 as shown in FIG. It can be manufactured by having the pipe 7 enter into the space.

Also shown in FIG. 11 is a core 1 made of metal A.
0 is shown in which a hollow body made of metal A is integrally connected to one end of the figure. In this case, the hollow body 7 on the right side of the figure enters the space, resulting in A pipe joint is obtained in the same manner as above.

In addition, in all the manufacturing methods described so far, one solid body or hollow body of metal A and one solid body or hollow body of metal B are butted together. After a large number of solid bodies or hollow bodies of metal A and those of metal B are inserted alternately into the inside of the metal A, a large number of them are subjected to hot isostatic pressure treatment at the same time, and then the solid bodies or hollow bodies of metal A are placed at appropriate locations. A large number of pipe joints can be obtained at the same time by cutting out the pipe joints and that of metal B as solid pieces, such as a pair of joints, and then removing the unfinished parts in the same manner as described above.

In addition, if it is undesirable for the metal A section and the metal B section to have a joint surface (butt end surface) in a direction perpendicular to the axis in the resulting pipe joint, for example due to stress concentration, This can be solved by cutting the mating surfaces diagonally in advance, and in order to further increase the joint strength between metal A part and metal B part, the joint surfaces of each other should be matched to make the joint surface larger. The uneven surface may be made as necessary.

The processing conditions such as temperature and pressure for hot isostatic pressing in the method of the present invention should be determined depending on the metal materials to be joined. In this case, the temperature is about 700℃, the pressure is about 1000 atm, and the processing time is 1
~2 hours.

<Effects of the Invention> As described above, according to the present invention, the area of the joined body of dissimilar metals on both sides forming a pipe joint can be increased, and the area of the joined body of dissimilar metals on both sides forming a pipe joint can be increased. In addition, since the joint is metallurgically and firmly joined, there is no fluid leakage from the joint, and it can be used for a wide range of purposes.

In addition, since the manufacturing method uses hot isostatic pressure treatment, it is possible to easily manufacture thin-walled and small-diameter products, and the type of metal used can be selected from a wide range. .

[Brief explanation of drawings]

1 to 4 are cross-sectional explanatory diagrams of a pipe joint obtained by the present invention, FIGS. 5 and 6 are cross-sectional explanatory diagrams of a conventional pipe joint, and FIG. 7 A is a cross-sectional explanatory diagram of a pipe joint of the present invention. Fig. 8 is an explanatory cross-sectional view showing an example of the manufacturing method of the pipe joint.
FIG. 11 are cross-sectional explanatory views showing another method of manufacturing the pipe joint of the present invention. In the figure, 1: part made of metal A, 2: part made of metal B.

Claims (1)

[Scope of Claims] 1. A solid body of a certain metal A and a solid body of metal B, which is different from the metal A, are butted together, and the outer periphery of the butted object is covered with a pipe made of the metal C, which is the same type or different from the metal B. The inner space of the pipe or the boundary between the pipe and the solid bodies of metals A and B are sealed from the outside by welding or other means to create a vacuum state, and then placed in a high-temperature and high-pressure container. After that, the core portions of both solid bodies of metals A and B are cut off leaving the required thickness on the outer periphery, and the outer circumferential pipe on the free end side of metal A is cut off. A method for manufacturing a pipe joint characterized by completely cutting off a portion to expose metal A. 2. The pipe according to claim 1, wherein one or both of the solid body of metal A and the solid body of metal B is a filling body such as metal powder, strip, block, etc. How to manufacture joints. 3 A hollow body of metal A and a hollow body of metal B, which is different from metal A, are butted together, and a solid or hollow core made of metal or non-metal is inserted into the inside of the butted body. , the outside of which is surrounded by a pipe made of the same or different metal C as the metal B,
The inner space of the pipe or the boundary between the pipe inner cylinder surface, the core outer cylinder surface, and the metals A and B are sealed from the outside by welding or other means to create a vacuum state, and then heated in a high-temperature, high-pressure container. Manufacture of a pipe joint characterized by applying isostatic pressure treatment for a period of time, then removing the core and completely cutting off the pipe portion on the free end side of the hollow body of metal A to expose metal A. Method. 4. The pipe joint according to claim 3, wherein one or both of the hollow body of metal A and the hollow body of metal B is a filled body of metal powder, strip, or lump. How to make int. 5 At one end of the core of a solid or hollow body, metal A
A hollow body made of metal A and shorter than the full length of the core is surrounded by each other with their ends aligned, and then a pipe made of metal B is further surrounded around the outer periphery of the hollow body made of metal A, and then inside the pipe The space or the mutual boundary between the inner cylinder surface of the pipe, the outer cylinder surface of the core, and the metal A is sealed from the outside by welding or other means to create a vacuum state, and then in a high temperature and high pressure container, hot isostatic pressure is applied. A method for producing a pipe joint, which comprises applying pressure treatment and then cutting off all the inner and outer parts of the metal A to expose the metal A on both the inner and outer sides. 6. The method for manufacturing a pipe joint according to claim 5, wherein the solid body made of metal A is a filling body such as a metal powder, strip, or block. 7. A method for producing a pipe joint according to claim 5, characterized in that the core is made of metal A, and the core and a hollow body made of metal A are integrally connected. .