JP3650486B2 - Liquid phase diffusion joint structure of metal pipe - Google Patents

Description

【００３４】
【表２】

【００３５】
【表３】

【００３６】
（１）表１は、第１の発明の実施例を示したものである。
サンプルNo．１〜５は図１に示すような内周面にテーパー面と環状壁を有する継手筒を用い、その内周テーパーと鋼管の外周テーパーの係合面、継手管の内側中央部に形成した環状壁面と鋼管の管端面間との衝接面を接合面として液相拡散接合した場合のものであり、表１のサンプルNo．６は継手筒の内周テーパーと鋼管の外周テーパーの係合面のみを接合面として液相拡散接合した場合のものである。
【００３７】
また、表１のサンプルNo．７は図１に示すような内周面にテーパーと環状壁を有する継手筒を用い、その環状壁面（テーパー面）と鋼管の管端面（テーパー面）の衝接面のみを接合面として接合した比較例である。
表１のサンプルNo．８は図２に示すような内周面にテーパーと環状壁を有する継手筒を用い、その内周テーパーと鋼管の外周テーパーの係合面、継手管の内側中央部に形成した環状壁面（テーパー面）と鋼管の管端面（テーパー面）の衝接面を接合面として液相拡散接合した場合のものであり、表１のサンプルNo．９は継手筒の内周テーパーと鋼管の外周テーパーの係合面のみを接合面として液相拡散接合した場合のものである。
【００３８】
また、表１のサンプルNo．１０は図２に示すような内周面にテーパー面と継手管の内側中央部に形成した環状壁を有する継手筒を用い、その環状壁面（テーパー面）と鋼管の管端面（テーパー面）の衝接面のみを接合面として液相拡散接合した比較例である。
これら第１の発明の実施例では、破断強度（kN）は３３７０〜３４００と、管体より高い強度の十分に満足できる接合部が得られた。
【００３９】
（２）表２は、第２の発明の実施例を示したものである。
サンプルNo．１〜３は図３に示すような外周面にテーパー面と外側中央部に環状壁を有する継手筒を用い、その外周テーパーと鋼管の内周テーパーの係合面、環状壁面と鋼管の管端面の衝接面を接合面として液相拡散接合した場合のものであり、表２のサンプルNo．４は、その外周テーパー面と鋼管の内周テーパー面の係合面のみを接合面として接合した場合のものである。
【００４０】
また、表２のサンプルNo．５は図３に示すような内周面にテーパーと環状壁を有する継手筒を用い、その環状壁面（テーパー面）と鋼管の管端面（テーパー面）の衝接面のみを接合面として接合した比較例である。
表２のサンプルNo．６は図４に示すような内周面にテーパーと外側中央部に環状壁を有する継手筒を用い、その外周テーパーと鋼管の内周テーパーの係合面、環状壁面と鋼管の管端面の衝接面を接合面として液相拡散接合した場合のものであり、表２のサンプルNo．７は、その外周テーパーと鋼管の内周テーパーの係合面のみを接合面として液相拡散接合した場合のものである。
【００４１】
また、表２のサンプルNo．８は図４に示すような内周にテーパー面と環状壁を有する継手筒を用い、その環状壁面（テーパー面）と鋼管の管端面（テーパー面）の衝接面のみを接合面として液相拡散接合した比較例である。
これら第２の発明の実施例では破断強度（kN）は３３６０〜３３９０と、管体より高い強度の十分に満足できる接合部が得られた。
【００４２】
（３）表３は、第１の発明と第２の発明の実施例において、継手筒の環状壁と管の端面の衝接面のみを接合面として接合した場合の鋼管の曲げ試験結果を示したものである。
表３のサンプルNo．１，２は図１に示すような第１の発明の実施例であり、表３のサンプルNo．３，４は図３に示すような第２の発明の実施例である。
いずれも継手筒の環状壁と鋼管の管端面の衝接面のみを接合面として液相拡散接合しているが、鋼管の管端部の外周テーパーと継手筒の内周テーパーとの係合面の長さを鋼管の直径の０．５〜１．０倍にすることにより、鋼管本体以上の曲げ強度を有する接合部が得られた。
【００４３】
なお、本発明は、上記の例に限定されるものではなく、炭素鋼の他、ステンレス鋼、その他の合金鋼からなる金属管を接合対象とする液相拡散接合にも適用できるものであり、液相拡散接合条件（加熱温度、圧縮応力負荷、接合面形状等）、スリーブ、加熱装置、押圧装置等の接合装置構成等については、接合対象管の材質および特性、接合材の材質、要求される接合部特性等に応じて、本発明の範囲内で変更されるものである。
【００４４】
【発明の効果】
本発明の液相拡散接合部構造においては、接合対象の金属管を管同士または継手筒を介して加熱、圧縮して液相拡散接合する場合の接合面を互いに接するテーパー面（環状壁面）とし、目違いや段差、軸心のずれの発生を防止して広い接合面に介在させた接合材を均一に密着させ、強固な接合部を安定確保することができる。
【図面の簡単な説明】
【図１】 本発明の金属管の液相拡散接合部構造例（第１の発明の第１例）を概念的に示す側断面説明図。
【図２】 本発明の金属管の液相拡散接合部構造例（第１の発明の第２例）を概念的に示す側断面説明図。
【図３】 本発明の金属管の液相拡散接合部構造例（第２の発明の第１例）を概念的に示す側断面説明図。
【図４】 本発明の金属管の液相拡散接合部構造例（第２の発明の第２例）を概念的に示す側断面説明図。
【図５】 金属管と金属管の接合面における目違いの状態を示す側断面説明図。
【図６】 金属管と金属管の接合面における軸心ずれの状態を示す側断面説明図。
【符号の説明】
１ａ，１ｂ ：金属管
１ｔ ：外周テーパー面
２ ：継手筒
２ｔ ：内周テーパー面
２ｗ ：環状壁
３，３ａ，３ｂ：接合材（非晶質金属箔）
４ ：加熱装置
５ ：押圧装置
５ｃ ：クランプ機構
５ｐ ：圧縮応力付与機構
６ａ，６ｂ ：金属管
６ｔ ：内周テーパー面
７ ：継手筒
７ｔ ：外周テーパー面
７ｗ ：環状壁
Ｐａ ：金属管
Ｐｂ ：金属管 [0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid phase diffusion joint structure of a metal tube obtained by joining opposing pipes to be joined directly or via a joint cylinder by liquid phase diffusion joining.
[0002]
[Prior art]
Conventionally, various welding methods are generally applied as a method for joining metal pipes, but in recent years, a liquid phase diffusion joining method has been applied instead of the welding method.
In this liquid phase diffusion bonding method, an alloy (amorphous metal) having a eutectic composition having a melting point lower than that of a material to be bonded is interposed between materials to be bonded in the form of foil, powder, or plating. This is a joining method in which the alloy is melted and isothermally solidified by pressurizing and heating the joint to a temperature just above the liquidus of the inserted alloy, and is considered a kind of solid-phase joining method.
[0003]
This liquid phase diffusion bonding provides a strong joint in a short time at a relatively low surface pressure. Conventionally, when stainless steel, high nickel-base alloy, heat-resistant alloy steel, or carbon steel and these are joined. Although it is widely used for those where it is difficult to apply welding methods, recently it has also been attempted to apply general steel pipes as objects to be joined. is expected.
[0004]
When this liquid phase diffusion bonding method is applied to a metal tube as an object to be bonded, it is common to interpose an amorphous metal (foil) as a bonding material on the bonding surface of the opposite metal tube. At the time of joining, it is necessary to align so that the joining surface and the amorphous metal foil are in uniform contact and the axes are parallel and coincide.
This alignment needs to be performed with much higher accuracy than in the case of a general welding method. (Reference Technology The Japan Society of Mechanical Engineers 1st Material, Material Processing Technology Lecture Paper 509 “Amorphous Bonding System”, described on P329, November 19, 1993).
[0005]
[Problems to be solved by the invention]
Conventionally, there is no aligning means in response to the wishes described above, the aligning work load is large, and in abutting surfaces of the pipe end of the metal tube Pa and the metal tube Pb to be joined as shown in FIG. 5, the eyes in difference a or abutting surfaces of the pipe end of the metal tube Pa and the metal pipe Pb as shown in FIG. 6, occurs axial misalignment b, the notch effect, aligning accuracy is not sufficient, the tensile axial force, or flexural There may be a problem that the joint strength at the time of loading decreases, a gap in the joint surface, a liquid phase penetration by a sufficient bonding material cannot be obtained, and a strong joint cannot be obtained, In the liquid phase diffusion bonding intended for bonding metal pipes, the advantages of the liquid phase diffusion bonding cannot often be fully enjoyed.
[0006]
There is a way to devise a groove shape as a means to reduce misalignment of the joint surface and tube axis deviation, but it is ideal because of the roundness of the tube, the influence of uneven thickness, difficulty in alignment at the construction site, etc. It is difficult to realize a joint with a specific shape.
[0007]
The present invention minimizes the occurrence of misunderstandings, steps, and axial misalignment as much as possible with simple aligning means when joining metal tubes by liquid phase diffusion joining, and ensures a stable and secure joint. A liquid phase diffusion bonding structure of a tube is provided.
[0008]
[Means for Solving the Problems]
1st invention of this invention inserts a metal pipe from the both sides of a joint pipe, and carries out liquid phase diffusion of the joining material distribute | arranged between the joint pipe and the metal pipe, and the liquid phase of the metal pipe which joined metal pipes during the diffusion bonding portion structure, a metal tube having a periphery tapered reduced in diameter in the end face direction tube end, the joint pipe provided with an inner peripheral taper diameter increases in the end face direction so as to be in contact with the outer peripheral tapered, And one or both of the annular wall formed at the inner central portion of the joint tube and the tube end surface of the metal tube as a bonding surface of the liquid phase diffusion bonding, Construction.
[0009]
According to a second aspect of the present invention, there is provided a liquid phase of a metal tube in which a joint tube is inserted into a tube end portion of the metal tube, and a joining material disposed between the joint tube and the metal tube is subjected to liquid phase diffusion to join the metal tubes together. during the diffusion bonding portion structure, and a metal tube provided with an inner peripheral taper diameter increases in the end face direction tube end, a joint cylinder with the outer peripheral tapered disposed in contact with the inner peripheral tapered reduced in diameter in the end face direction And any one or both of the annular wall formed at the outer central portion of the joint tube and the tube end surface of the metal tube as a bonding surface of the liquid phase diffusion bonding. Part structure.
[0010]
A third invention is Oite the first invention or the second invention, a liquid phase diffusion bonding part structure, wherein the bonding material is an amorphous metal.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The present invention minimizes the occurrence of misunderstandings, steps and axial misalignment as much as possible when metal pipes made of, for example, general steel, stainless steel, high nickel alloy, etc. are joined by the liquid phase diffusion bonding method. In order to secure a stable joint having a strength higher than the tensile breaking strength of the pipe body in the joining operation, the joining surface for liquid phase diffusion joining with the joining material interposed between the pipe ends facing each other This is a liquid phase diffusion junction structure of a metal pipe that is tapered so as to be in contact with each other or between the pipe end part and the joint tube to enhance alignment.
[0012]
The important construction issues when joining opposite pipe ends by liquid phase diffusion bonding are as described above, with no joints, steps, or axial misalignment between the opposite pipe ends. The contact pressure is applied in a state where there is no gap on the joint surface, and sufficient adhesion between the joint surface and the joining material is ensured.
In the present invention, since the opposing tapered surfaces start to interfere, the alignment of the pipes to be joined is improved without performing special alignment work, and the joint surface and the amorphous metal are aligned with the axis. Can be sufficiently secured, and a sufficient bonding strength can be secured.
[0013]
In order to ensure the self-alignment smoothly and sufficiently, and to ensure sufficient bonding strength, the angle between one metal tube forming the bonding surface and the end tapered surface of the other metal tube (or joint tube) It is necessary to fully consider the length.
The taper surface for forming the joint surface can be selected so that the diameter increase / decrease value is in the range of 1/20 to 1/3 with respect to the axial distance 1 in terms of the increase / decrease value of the diameter. desirable.
[0014]
Here, if it is less than 1/20, the self-aligning effect is reduced, and when the joint is not used, the overlapping portion becomes too long, and the length loss of the entire pipe increases. If it exceeds 1/3 degrees, self-sustainability is lost and the self-aligning effect is reduced even for misalignment. In addition, the engagement resistance between one tube and the other tube (or joint tube) increases, and smooth engagement cannot be achieved, and a sufficient joint area cannot be secured, so that a sufficient joint strength can be secured. Disappear.
[0015]
The outline of each invention of the present invention will be described below.
1 and 2 show an example of a liquid phase diffusion junction structure according to the first invention.
The outer periphery taper 1t which is diameter-reduced to an end surface direction is formed in the outer periphery of the edge part of the metal pipes 1a and 1b to be joined, and this outer periphery taper 1t is both sides of the joint cylinder 2 whose outer diameter is larger than that of the metal pipe. It is engaged with an inner peripheral taper 2t which is formed on the inner periphery of the section and expands in the end face direction.
Here, this engagement surface is used as a bonding surface, and a bonding material 3a for liquid phase diffusion bonding is interposed in this engagement surface.
[0016]
Further, an annular wall 2w is formed at the inner peripheral central portion of the joint tube 2, and the pipe end surfaces of the metal tubes 1a and 1b are in contact with the side surfaces of the annular wall 2w. Here, this abutting surface is also used as a joining surface, and a joining material 3b for liquid phase diffusion joining is interposed in this abutting surface.
In this state, the pressing device provided with the clamp mechanism 5c and the compressive stress applying mechanism 5p while heating the joining surface and its peripheral portion (hereinafter referred to as "joining portion") by the heating device 4 disposed outside the joint tube 2. 5, compressive stress is applied in the direction of the arrow to melt the joining materials 3a and 3b interposed in the joining surface, and the ends of the metal pipes 1a and 1b are liquid phase diffusion joined via the joint cylinder 2, The liquid phase diffusion bonding structure of the metal pipe of the first invention can be obtained.
[0017]
In this example of the liquid phase diffusion bonding structure of the metal tube, the bonding surface is between the outer peripheral taper 1t of the end of the metal tube 1a, 1b and the inner peripheral taper 2t of the joint tube 2, the tube end surface of the metal tube 1a, 1b and the joint tube. Since it is formed between the two annular walls 2w, alignment is easy, the joining area can be increased, and the joint strength can be increased.
Further, when the end portions of the metal tubes 1a and 1b are inserted into the joint tube 2, the compressive stress load does not become excessive because the tube end surface abuts against the side surface of the annular wall 2w at the final stage. Will not be deformed.
[0018]
In addition, after the ends of the metal tubes 1a and 1b are press-fitted into the joint cylinder 2, the taper 1t and 2t, which are the joint surfaces, are opposed to each other. Since it is self-supporting in the applied state, it is not necessary to newly apply a surface pressure during heating, and the heating operation can be remarkably simplified.
[0019]
In FIG. 1 , the end surfaces of the metal tubes 1a and 1b and the abutting surface of the annular wall 2w are confronted. In FIG. 2 , the tube end surfaces of the metal tubes 1a and 1b are tapered, and the annular surface is in contact with the taper. The shape of the wall 2w is wedge-shaped and the contact surface is tapered to increase the surface pressure at the contact surface between the tube end surfaces of the metal tubes 1a and 1b and the annular wall 2w when it stands on its own.
[0020]
In this metal pipe liquid phase diffusion joint structure example, the joint surface is formed in a wide area between the joint tube 2 and the pipe end of the metal pipe in a state where the joint surface is constrained by the taper of the pipe end and the annular wall 2w. As a result of the effective reinforcement effect of the joint tube, the rigidity of the joint is greater than that of the tube main body, and plastic deformation due to loads such as compression, tension, and bending is unlikely to occur.
Depending on the direction and size of the load, it may be sufficient to form the joining surface only on the tapered surface of the pipe end and the joint tube or the abutting surface of the annular wall 2w.
[0021]
For example, in joining steel pipe piles that are mainly bent, only the contact surface between the annular wall 2w and the pipe end face may be joined. In this case, the taper length is 0.5 to 1.0 of the pipe diameter. By doing so, the pipe end portion is constrained by the joint tube without connecting the tapered surfaces, so that it is possible to obtain a joint strength higher than the tube bending strength.
With this design, it is possible to avoid the use of a bonding material on the tapered surface of the pipe end, thereby reducing costs and improving workability.
[0022]
3 and 4 show an example of a liquid phase diffusion junction structure according to the second invention.
In the first aspect of the invention described above, although the outer diameter of a metal tube end opposing the metal pipe to be joined are liquid phase diffusion bonding by a bonding material in the joint barrel peripheral side of the large diameter, the second invention Then, a joint tube having a smaller outer diameter than the metal tube is inserted into the end portion of the metal tube to be joined, and liquid phase diffusion bonding is performed using a joining material disposed between the metal tube and the joint tube.
[0023]
In this liquid phase diffusion joint structure, the same effects as in the first invention can be obtained, and the joint tube has an effect of not expanding the outer diameter of the pipe. For example, a metal pipe pile driven into the ground, It is suitable for application when joining a metal tube or the like that is inserted into a space slightly larger than the diameter.
[0024]
In this liquid phase diffusion junction structure, an inner circumference taper 6t that is expanded in the end face direction is formed on the inner circumference of the ends of the metal pipes 6a and 6b to be joined, and this inner circumference taper has an outer diameter larger than that of the metal pipe. Is engaged with an outer peripheral taper 7t having a reduced diameter toward the end face formed on the outer periphery of both side portions of the small-diameter joint cylinder 7. Here, this engagement surface is used as a bonding surface, and a bonding material 3a for liquid phase diffusion bonding is interposed in this engagement surface.
[0025]
Further, an annular wall 7w is formed at the outer peripheral center of the joint tube 7 so that the tube end surfaces of the metal tubes 6a and 6b come into contact with each other. Here, this abutting surface is also used as a joining surface, and a joining material 3b for liquid phase diffusion joining is interposed in this abutting surface.
[0026]
In FIG. 4 , when the pipe end faces of the metal pipes 6a and 6b are formed in a taper shape, the shape of the annular wall 2w that engages the taper face of the pipe end face is a wedge shape, and the contact surface is a taper shape. The surface pressure at the abutting surface between the pipe end faces of the metal pipes 6a and 6b and the annular wall 7w is increased.
[0027]
In this state, a clamping mechanism 5c and a compressive stress applying mechanism 5p are provided while heating the joining surface and its peripheral part (hereinafter referred to as “joining part”) by the heating device 4 disposed outside the pipe end part of the metal pipe. The pressing device 5 ( see FIG. 1 ) applies a compressive stress to melt the joining materials 3a and 3b interposed in the joining surface, and the ends of the tubes 6a and 6b are connected to the liquid phase via the joint cylinder 7. By diffusion bonding, the liquid phase diffusion junction structure of the second invention can be obtained.
[0028]
Various heating devices (means) 4 used in the above-described embodiments of the present invention are conceivable. An electric heating device such as an induction heating device, an electric heating device, and an electric heater that can easily and uniformly heat the joint is suitable. Although it is generally high and is disposed on the outer peripheral side of the joint cylinder, it may be built in the joint cylinder or the joint cylinder itself may be used as a heating element.
[0029]
The heating temperature is selected in consideration of the material of the metal pipe, the type of the joining material, the characteristics required for the joint, etc., as long as the joining material melts and the characteristics of the pipe to be joined do not deteriorate. In the case, it is 900-1200 degreeC.
[0030]
The compressive stress load at the joint is usually 1 to 100 MPa (megapascals), and the pressing device 5 therefor has a simple structure including a clamp mechanism 5c and a compressive stress applying mechanism 5p. It is enough.
The joint cylinder also serves as reinforcement of the joint, and is formed of a metal having a strength equal to or higher than that of the metal pipe to be joined and capable of ensuring sufficient joint strength by liquid phase diffusion joining with the metal pipe. It is preferable.
[0031]
Further, since the bonding in the present invention is a liquid phase diffusion bonding, for example, an Fe-based, Ni-based, or Cu-Ti-based amorphous metal (foil) having a uniform and stable liquid phase diffusibility is used as a bonding material. Is preferred.
The diffusion bonding referred to in the present invention means liquid phase diffusion bonding in which liquid phase diffusion is 50% or more, and includes diffusion brazing bonding.
[0032]
【Example】
The implementation result and evaluation result of each invention of the present invention will be described based on Tables 1 to 3 .
In this example, liquid phase diffusion bonding using a steel pipe (material, STK400) having an outer diameter of 267 mm and a wall thickness of 9.3 mm as a bonding target and an amorphous metal foil as a bonding material was performed. A tensile fracture test was performed, and the fracture strength (kN) was evaluated. As the bonding material, an amorphous metal foil of B: 8 wt%, Si: 10 wt%, V: 12 wt%, Fe: remaining component was used.
In addition, the numerical value of the joint surface taper of each table | surface is shown by the increase / decrease value of the diameter with respect to the distance 1 parallel to an axis.
[0033]
[Table 1 ]

[0034]
[Table 2 ]

[0035]
[Table 3 ]

[0036]
( 1 ) Table 1 shows examples of the first invention.
Sample No. 1 to 5 use a joint cylinder having a tapered surface and an annular wall on the inner peripheral surface as shown in FIG. 1 , an engagement surface of the inner peripheral taper and the outer peripheral taper of the steel pipe, and an annular formed on the inner central portion of the joint pipe are those in the case of liquid-phase diffusion bonding as the bonding surface abutment surface between the between the pipe end face of the wall and the steel pipe, samples of Table 1 No. 6 is a case where liquid phase diffusion bonding is performed using only the engagement surfaces of the inner peripheral taper of the joint tube and the outer peripheral taper of the steel pipe as the joint surfaces.
[0037]
In addition, samples in Table 1 No. 7 is a joint cylinder having a taper and an annular wall on the inner peripheral surface as shown in FIG. 1 , and only the abutting surface of the annular wall surface (taper surface) and the pipe end surface (taper surface) of the steel pipe is joined as a joining surface. It is a comparative example.
Sample No. in Table 1 8 uses a joint cylinder having a taper and an annular wall on its inner peripheral surface as shown in FIG. 2 , an engagement surface of the inner peripheral taper and the outer peripheral taper of the steel pipe, and an annular wall surface (tapered) formed on the inner central portion of the joint pipe. is of the case where the abutment surface of the surface) and the pipe end face of the steel tube (tapered surface) and the liquid phase diffusion bonding as the bonding surface, samples of Table 1 No. Reference numeral 9 denotes a case where liquid phase diffusion bonding is performed using only the engagement surfaces of the inner peripheral taper of the joint tube and the outer peripheral taper of the steel pipe as the bonding surfaces.
[0038]
In addition, samples in Table 1 No. 2 uses a joint cylinder having a tapered surface and an annular wall formed in the inner central portion of the joint pipe as shown in FIG. 2 , and the annular wall surface (taper surface) and the pipe end surface (taper surface) of the steel pipe. This is a comparative example in which liquid phase diffusion bonding is performed using only the contact surface as a bonding surface.
In these Examples of the first invention, the fracture strength (kN) was 3370 to 3400, and a sufficiently satisfying joint having a higher strength than the tubular body was obtained.
[0039]
( 2 ) Table 2 shows examples of the second invention.
Sample No. 1 to 3 use a joint cylinder having a tapered surface on the outer peripheral surface and an annular wall at the outer central portion as shown in FIG. 3 , the engagement surface of the outer peripheral taper and the inner peripheral taper of the steel pipe, the annular wall surface and the pipe end surface of the steel pipe Sample No. in Table 2 was obtained when liquid phase diffusion bonding was performed using the contact surface of 4 is a case where only the engagement surface of the outer peripheral taper surface and the inner peripheral taper surface of the steel pipe is joined as a joint surface.
[0040]
Sample No. in Table 2 3 uses a joint cylinder having a taper and an annular wall on its inner peripheral surface as shown in FIG. 3 , and the annular wall surface (taper surface) and only the abutting surface of the pipe end surface (taper surface) of the steel pipe are joined as a joining surface. It is a comparative example.
Sample No. in Table 2 6 uses a joint tube having a taper on the inner peripheral surface and an annular wall at the outer center as shown in FIG. 4 , and the contact between the outer peripheral taper and the inner peripheral taper of the steel pipe, and between the annular wall and the pipe end surface of the steel pipe. are those in the case of liquid-phase diffusion bonding the contact surface as a bonding surface, samples in Table 2 No. 7 is a case where liquid phase diffusion bonding is performed using only the engagement surface of the outer peripheral taper and the inner peripheral taper of the steel pipe as a bonding surface.
[0041]
Sample No. in Table 2 8 uses a joint cylinder having a tapered surface and an annular wall on the inner periphery as shown in FIG. 4, and a liquid phase having only an abutting surface of the annular wall surface (taper surface) and a pipe end surface (taper surface) of the steel pipe as a joint surface. It is the comparative example which carried out diffusion bonding.
In these examples of the second invention, the fracture strength (kN) was 3360 to 3390, and a sufficiently satisfying joint having a higher strength than the tubular body was obtained.
[0042]
( 3 ) Table 3 shows the bending test results of steel pipes in the first invention and the embodiment of the second invention when only the abutting surfaces of the annular wall of the joint cylinder and the end face of the pipe are joined. It is a thing.
Sample No. in Table 3 1 and 2 are examples of the first invention as shown in FIG. 1, the sample of Table 3 No. Reference numerals 3 and 4 are embodiments of the second invention as shown in FIG.
In both cases, liquid phase diffusion bonding is performed using only the abutting surface of the annular wall of the joint tube and the pipe end surface of the steel pipe as the joint surface, but the engagement surface between the outer peripheral taper of the pipe end of the steel pipe and the inner peripheral taper of the joint cylinder By making the length of the steel pipe 0.5 to 1.0 times the diameter of the steel pipe, a joint having a bending strength higher than that of the steel pipe main body was obtained.
[0043]
The present invention is not limited to the above example, and can be applied to liquid phase diffusion bonding in which metal pipes made of stainless steel and other alloy steels are to be joined in addition to carbon steel. Regarding the liquid phase diffusion bonding conditions (heating temperature, compressive stress load, bonding surface shape, etc.), the bonding device configuration such as sleeve, heating device, pressing device, etc., the material and characteristics of the pipe to be bonded, the material of the bonding material, and the required It is changed within the scope of the present invention in accordance with the junction characteristics and the like.
[0044]
【The invention's effect】
In the liquid phase diffusion joint structure of the present invention, when joining metal pipes to be joined together by heating or compressing each other through a pipe tube, the joining surfaces are tapered surfaces (annular wall surfaces) that contact each other. In addition, it is possible to prevent the occurrence of misplacement, step difference, and axial misalignment, and to evenly adhere the bonding material interposed on the wide bonding surface, and to secure a stable strong bonding portion.
[Brief description of the drawings]
Figure 1 is a side cross-sectional view conceptually showing a (first example of the first invention) liquid phase diffusion joint structure of a metal tube of the present invention.
FIG. 2 is an explanatory side sectional view conceptually showing an example of the structure of a liquid phase diffusion bonding portion of a metal tube according to the present invention (second example of the first invention).
FIG. 3 is an explanatory side cross-sectional view conceptually showing an example of the structure of a liquid phase diffusion bonding part of a metal tube of the present invention (first example of the second invention).
Figure 4 is a side cross-sectional view conceptually showing a (second example of the second invention) liquid phase diffusion joint structure of a metal tube of the present invention.
FIG. 5 is an explanatory side cross-sectional view showing a state of a mistake in the joint surface between the metal tube and the metal tube.
FIG. 6 is an explanatory side cross-sectional view showing a state of axial misalignment at the joint surface between the metal tube and the metal tube.
[Explanation of symbols]
1a, 1b: Metal pipe 1t: Outer peripheral taper surface 2: Joint tube 2t: Inner peripheral taper surface 2w: Annular wall 3, 3a, 3b: Bonding material (amorphous metal foil)
4: Heating device 5: Pressing device 5c: Clamp mechanism 5p: Compression stress applying mechanism 6a, 6b: Metal pipe 6t: Inner peripheral tapered surface 7: Joint cylinder 7t: Outer peripheral tapered surface 7w: Annular wall
Pa : Metal pipe
Pb : Metal pipe

Claims (3)

In the liquid phase diffusion joint structure of a metal tube in which a metal tube is inserted from both sides of the joint tube, the bonding material disposed between the joint tube and the metal tube is subjected to liquid phase diffusion, and the metal tubes are joined to each other. an outer taper whose diameter is reduced into a metal tube provided in the tube end, between the joint tube provided with inner taper diameter increases in the end face direction so as to be in contact with the outer peripheral tapered, and the inner central portion of the joint tube A liquid phase diffusion junction structure for a metal tube, wherein either or both of the formed annular wall and the tube end surface of the metal tube are used as a junction surface for liquid phase diffusion bonding. In the liquid phase diffusion joint structure of the metal pipe, the joint pipe is inserted into the pipe end of the metal pipe, the joining material disposed between the joint pipe and the metal pipe is subjected to liquid phase diffusion, and the metal pipes are joined together. between a metal tube provided with an inner peripheral taper diameter increases in the end face direction tube end, a joint cylinder with the outer peripheral tapered disposed in contact with the inner peripheral tapered reduced in diameter in the end face direction, and the outside of the joint tube A liquid phase diffusion junction structure for a metal tube, wherein either or both of an annular wall formed at a central portion and a tube end surface of the metal tube are used as a junction surface for liquid phase diffusion bonding. The liquid phase diffusion bonding structure according to claim 1 or 2 , wherein the bonding material is an amorphous metal.

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