WO2016038691A1 - Method for manufacturing pipe joint and pipe joint - Google Patents

Abstract

This method for manufacturing a pipe joint is a method for manufacturing a pipe joint wherein a second metal pipe (20) is joined to an outside side surface of a first metal pipe (10). The method includes, in this order, a first step for preparing the first metal pipe (10), which is provided with a through hole (12) and a protruding part that "is formed so as to surround the through hole (12), has an inclined outer surface, and protrudes toward the outside from the side surface of the first metal pipe (10)", and the second metal pipe (20), which is provided with an inside surface end part, and a second step for solid state diffusion bonding of the metal pipes by electrifying while applying pressure between the protruding part and the inside surface end part. Thereby, a pipe joint with residual compressive stress in the joint part can be manufactured. Thus, it is possible to increase the durability for corrosion and the durability for metal fatigue of the pipe joint that is manufactured, suppress reductions in strength of the manufactured pipe joint, and increase productivity.

Description

Method for manufacturing pipe joined body and pipe joined body

The present invention relates to a method for manufacturing a pipe joined body and a pipe joined body.

In this specification, the “pipe joined body” means “the second metal pipe is joined to the outside of the side surface of the first metal pipe along a predetermined connection axis, and the inner space of the first metal pipe and the first metal pipe are joined. It means that the internal space of two metal pipes is connected. As a typical example, as shown in an embodiment to be described later, a first metal pipe and a second metal pipe joined in a T shape (see FIG. 1) can be given.

The above-described pipe joined body is used in various fields as a part of piping in order to mainly divide or join fluids. As a specific example, there can be mentioned an airbag system mainly used for automobiles.

As one of the safety technologies for automobiles, there is passive safety technology that aims to reduce the damage to passengers when a collision occurs. The airbag system described above is the core technology of passive safety technology together with the seat belt. The types of airbags include driver and passenger airbags corresponding to frontal collisions, side airbags and curtain shield airbags corresponding to side collisions, knee airbags protecting the lower limbs, and rear passengers. There are rear seat airbags, rear window curtain shield airbags for rear-end collisions, etc., and the progress is remarkable.

When the airbag system is in operation, the gunpowder is burned with an inflator (a filling machine or a type of air pump) to generate gas, and the airbag is inflated with the gas in units of 0.05 seconds. Therefore, in order to withstand the high pressure caused by gas, the piping used in the airbag system is required to have high strength.

As a method for joining pipes used for piping with high strength, for example, a method using solid phase diffusion joining is known (see, for example, Patent Document 1). However, since this method does not assume that another metal pipe is joined to the outside of the side surface of a certain metal pipe, it is difficult to manufacture a pipe joined body as used in this specification by using this method.

Therefore, conventionally, a method using melt welding or a method using brazing in a furnace is widely used as a method for manufacturing a pipe joined body.
13 and 14 are views for explaining a conventional method of manufacturing a pipe joined body. FIGS. 13A and 13B are process diagrams of a method using fusion welding, and FIGS. 14A and 14B are process diagrams of a method using brazing in a furnace.

As shown in FIG. 13, the manufacturing method of the pipe joined body using fusion welding includes a first metal pipe 910 (for example, made of carbon steel) including a through hole 912 formed on the side surface of the first metal pipe 910, A step of preparing a second metal pipe 920 (for example, made of carbon steel) provided with a connecting end 922 corresponding to the shape in the vicinity of the through-hole 912 (see FIG. 13A), the second metal. After the pipe 920 is combined with the first metal pipe 910 along a predetermined connection axis (in FIG. 13, the same as the axis ax2 of the second metal pipe 920), the first metal pipe 910 and the second metal pipe 910 and the second metal pipe 910 are joined by fusion welding. The process of joining the metal pipes 920 (see FIG. 13B) is performed in this order, and the pipe joined body 900 is manufactured. In addition, what is shown with the code | symbol 930 of FIG.13 (b) is the part which performed the fusion welding.

As shown in FIG. 14, the method for manufacturing a pipe assembly using brazing in the furnace has a first metal pipe 910 having a through hole 912 formed on the side surface of the first metal pipe 910 and a shape in the vicinity of the through hole 912. A step of preparing a second metal pipe 920 having a corresponding connection end 922 and a metal ring 940 for brazing (for example, made of pure copper) (see FIG. 14A), and the second metal pipe 920 In addition, the metal ring 940 is combined with the first metal pipe 910 so as to be along a predetermined connection axis (same as the axis ax2 of the second metal pipe 920 in FIG. 14), and then heated in a furnace to thereby form the metal ring. 940 is melted, and the process of joining the 1st metal pipe 910 and the 2nd metal pipe 920 in this order is included, and the pipe joined body 902 is manufactured. Note that reference numeral 942 in FIG. 14B indicates a portion made of brazing metal.

According to the conventional method of manufacturing a pipe joined body, it is possible to produce a pipe joined body that splits or joins fluids by joining the second metal pipe to the outside of the side surface of the first metal pipe.

Japanese Patent No. 4440229

However, the conventional method for manufacturing a pipe joined body has the following problems.
First, in the manufacturing method of a pipe joined body using fusion welding, the metal structure of the portion where the fusion welding is performed is referred to as a molten solidification phase due to melting of the metal material constituting each metal pipe at the time of fusion welding. It becomes a heterogeneous structure (a kind of cast structure). For this reason, the manufacturing method of a pipe joined body using fusion welding has a problem that durability against corrosion and metal fatigue of the produced pipe joined body is lowered due to deterioration of mechanical properties.

In addition, in the method for manufacturing a pipe joined body using fusion welding, tensile stress remains in the portion where the fusion welding is performed. From this point of view, the durability of the produced pipe joined body against corrosion and durability against metal fatigue can be obtained. There is a problem of being lowered. The above problem becomes more serious when the pipe joint is used in a severe environment exposed to long-term vibration and stress such as automobile parts and in a field requiring high safety.

Next, in the method of manufacturing a pipe assembly using brazing in a furnace, it is necessary to expose each metal pipe to a high temperature for a long time in order to melt the brazing metal. Specifically, when the brazing metal is copper, the brazing atmosphere temperature is 1120 ° C., and the total process time is 40 minutes. The temperature of 1120 ° C. is a temperature higher than the austenitizing temperature of steel material (about 800 ° C.), and when it is cooled slowly after being held at the temperature, the metal material constituting each metal pipe is annealed. Therefore, there is a problem in that there is a concern about strength reduction in the manufactured pipe joined body.

In addition, in the method of manufacturing a pipe assembly using brazing in the furnace, a brazing metal is set between the first metal pipe and the second metal pipe, and the brazing metal is put into the furnace. In many cases, metal pipes are temporarily joined by a method such as welding. For this reason, the manufacturing method of the pipe joined body using brazing in the furnace has a problem that the number of processing steps increases, and the productivity is lowered from the viewpoint of the number of steps and the cost. The above problem is serious because pipe assemblies are mass-produced (for example, producing tens of thousands or more per month).

Therefore, the present invention has been made to solve the above problems, and compared with the conventional method for manufacturing a pipe joined body, the durability of the manufactured pipe joined body against corrosion and the durability against metal fatigue are increased. It is an object of the present invention to provide a method for manufacturing a pipe joined body that can be reduced, can suppress a decrease in strength in the produced pipe joined body, and can increase productivity. Moreover, it aims at providing the pipe joined body manufactured by the said manufacturing method.

[1] In the method for manufacturing a pipe joined body according to the present invention, the second metal pipe is joined along the predetermined connection axis to the outside of the side surface of the first metal pipe, and the internal space of the first metal pipe and the A method of manufacturing a pipe joined body in which an internal space of a second metal pipe is connected, wherein a through-hole formed in a side surface of the first metal pipe, and "formed so as to surround the through-hole; and The first metal pipe having an inclined outer surface inclined at a predetermined angle with respect to the predetermined connection axis, and including a protruding portion protruding outward from a side surface of the first metal pipe; A first step of preparing the second metal pipe having an inner surface end portion in contact with the inclined outer surface of the projecting portion when combining the first metal pipe and the second metal pipe; and the first metal pipe and the first metal pipe 2 metal pipes with the predetermined contact After being combined along the axis, the first metal pipe and the second metal are applied by solid phase diffusion bonding using electrical resistance heat generated by energization as an energy source while applying pressure between the protrusion and the inner surface end. And a second step of joining the pipes in this order.

According to the method for manufacturing a pipe joined body of the present invention, the fluid is divided or separated by joining the second metal pipe to the outside of the side surface of the first metal pipe, as in the conventional method for producing a pipe joined body. It is possible to manufacture a pipe assembly to be joined.

In addition, according to the method for manufacturing a pipe joined body of the present invention, since the pipe joined body is manufactured using solid-phase diffusion bonding that uses electrical resistance heat generated by energization instead of melt joining, a melt-solidified phase is not generated. Since deterioration of mechanical properties can be prevented, it becomes possible to increase durability against corrosion and durability against metal fatigue in the manufactured pipe joined body, as compared with a method of manufacturing a pipe joined body using fusion joining. .

Further, according to the method for manufacturing a pipe joined body of the present invention, since the pipe joined body is manufactured using the solid phase diffusion joining, compressive stress remains in the joined portion (see the experimental example described later). Also from this viewpoint, it is possible to increase the durability against corrosion and the durability against metal fatigue in the manufactured pipe joined body, as compared with the method for producing a pipe joined body using fusion joining.

In addition, according to the method for manufacturing a pipe assembly of the present invention, since the pipe assembly is manufactured using the solid phase diffusion bonding, each metal pipe does not need to be exposed to a high temperature for a long time, and each metal pipe is configured. Since it is possible to prevent the metal material from being annealed, it is possible to suppress a decrease in strength in the manufactured pipe joined body as compared with a method for producing a pipe joined body using brazing in the furnace.

In addition, according to the method of manufacturing a pipe joined body of the present invention, since there is no need to prepare a metal for brazing or temporary joining of a metal pipe, the number of processes is compared with a pipe joined body using brazing in a furnace. From the viewpoint of the above and the cost, it becomes possible to increase the productivity.

For this reason, the manufacturing method of the pipe joined body of the present invention can increase the durability against corrosion and the durability against metal fatigue in the manufactured pipe joined body, as compared with the manufacturing method of the conventional pipe joined body. And it becomes possible to suppress the strength fall in the manufactured pipe joined body, and it becomes the manufacturing method of the pipe joined body which can make productivity high.

Moreover, according to the manufacturing method of the pipe joined body of the present invention, since the first metal pipe having the projecting portion is used, it is possible to easily align when the first metal pipe and the second metal pipe are combined. In addition, it is possible to manufacture a pipe joined body that is relatively strong against a force in a direction orthogonal to a predetermined connection axis.

Incidentally, in solid phase diffusion bonding, the cleanliness of the bonding surface determines the quality of bonding. According to the method for manufacturing a pipe joined body of the present invention, since pressure is applied between the protrusion and the inner surface end, the surface of the protrusion and the inner end surface can be scraped to clean the bonding surface. It is possible to perform solid phase diffusion bonding under favorable conditions.

Due to the above effects, the method for manufacturing a pipe joined body according to the present invention is highly safe in a harsh environment exposed to vibration and stress for a long period of time, such as automobile parts (airbag system piping). This is a method suitable for the manufacture of parts (pipe joints) used in fields requiring the above.

In the present specification, the “side surface” refers to a “side surface” when the side of the first metal pipe having the opening is the front when the central axis of the first metal pipe is a straight line (described later). (See FIG. 1). When the central axis of the first metal pipe is not a straight line, the tangent of the central axis of the first metal pipe closest to the joint portion between the first metal pipe and the second metal pipe or the place where the joint portion is to be joined is used as a reference. Think about the “side”.

The “predetermined connection axis” in this specification refers to an attachment axis for the second metal pipe when the central axis of the second metal pipe is a straight line. When the center axis of the second metal pipe is not a straight line, a “predetermined connection axis” is considered with reference to the tangent line of the center axis of the second metal pipe closest to the inner surface end.
Since the “projection” in the present specification is formed so as to surround the through-hole, particularly when the through-hole has a circular shape or a shape close to a circle (for example, an ellipse), it is referred to as an “annular projection”. You can also

“A through-hole formed in the side surface of the first metal pipe,” “having an inclined outer surface formed so as to surround the through-hole and inclined at a predetermined angle with respect to the predetermined connection axis; "The first metal pipe having a protrusion protruding outward from the side surface of the first metal pipe" is "formed so as to surround a through-hole opened in the side surface of the first metal pipe; and , "The first metal pipe having an inclined outer surface that is inclined at a predetermined angle with respect to the predetermined connection shaft and having a protruding portion protruding outward from the side surface of the first metal pipe". You can also

“Electric resistance heat generation” has the same meaning as “Joule heat”.
“Energy source” has the same meaning as “heat source”.

As a metal material constituting the first metal pipe and the second metal pipe, any metal material can be used as long as solid phase diffusion bonding using electrical resistance heat generation by energization as an energy source is possible.
As the first metal pipe and the second metal pipe, pipes having a central axis that is a straight line can be suitably used, but pipes having a central axis that is not a straight line (the central axis is a curve, a broken line, or the like) are used. You can also

As the first metal pipe and the second metal pipe, those having a circular cross-sectional shape can be suitably used. However, as long as it is possible to form a protrusion having an appropriate shape, the cross-sectional shape is other than circular. The present invention can also be applied to (having an elliptical shape, polygonal shape, etc.).
The predetermined connection axis may be orthogonal to the central axis of the first metal pipe, may be crossed obliquely, or may not cross.

The manufacturing method of the pipe joined body of the present invention may be carried out by preparing one first metal pipe and one second metal pipe (see the embodiment described later). In addition, one first metal pipe and a plurality of second metal pipes may be prepared and implemented (see Modification 1 and FIG. 11 described below as an example), or a plurality of first metal pipes. One first metal pipe may be prepared and carried out, or a plurality of first metal pipes and a plurality of second metal pipes may be prepared and carried out.

When one or both of the first metal pipe and the second metal pipe are plural, the pipe joined body is formed by joining three or more metal pipes at a time (that is, in one second step). It may be manufactured. However, in this case, from the viewpoint of bonding reliability, the bonding of one first metal pipe and one second metal pipe is sequentially performed (that is, a total of n first metal pipes and second metal pipes). If there is a pipe, it is preferable to manufacture the pipe assembly by repeating the present invention n-1 times).

In the manufacturing method of the pipe joined body of the present invention, the second step is after combining the first metal pipe and the second metal pipe along the predetermined connection axis and before performing the solid phase diffusion joining, A pressure (preload pressure) smaller than the “pressure applied between the protrusion and the inner surface edge when performing solid phase diffusion bonding” (main pressure) is applied between the protrusion and the inner surface edge (preload). Is more preferable. By setting it as such a method, it becomes possible to combine a 1st metal pipe and a 2nd metal pipe more stably.
The preload pressure can be an arbitrary pressure depending on the type of metal pipe used.

[2] In the method for manufacturing a pipe joined body of the present invention, it is preferable that the energization time is 1 second or less in the second step.

By adopting such a method, the heating time can be sufficiently shortened to prevent the metal material constituting the protruding portion and the inner surface end from being annealed, and as a result, the strength reduction in the vicinity of the joint portion can be sufficiently prevented. Can be suppressed.

[3] In the method for producing a pipe joined body of the present invention, in the second step, initial pressurization is performed immediately before energization for the solid phase diffusion bonding, and pressurization is continued from the initial pressurization. It is preferable that the first metal pipe and the second metal pipe are bonded together by the solid phase diffusion bonding.

By adopting such a method, the contact between the protruding portion and the inner surface end can be made good before solid phase diffusion bonding is performed, and a uniform current can flow through the protruding portion and the inner surface end.

The pressure applied in the initial pressurization (initial pressurization pressure) may be the same as, for example, “the pressure applied between the protrusion and the inner surface end when performing solid phase diffusion bonding” (the main pressurization pressure). it can.
Specifically, the initial pressurizing pressure is “When the initial pressurization is performed, the protrusion layer surface and the inner surface end surface are substantially free from scraping of the impurity layer on the surface of the protruding portion and the inner surface end surface. It is preferable that the impurity layer is scraped. By adopting such a method, it is possible to suppress damage to each metal pipe due to excessive application of initial pressurizing pressure, and it is possible to perform solid phase diffusion bonding under sufficiently good conditions.

[4] In the method for manufacturing a pipe joined body according to the present invention, it is preferable that the inclined outer surface has an inclination angle with respect to the predetermined connecting axis within a range of 5 to 80 °.

By adopting such a method, the contact angle between the inclined outer surface and the inner surface end can be made appropriate, the scraping of the impurity layer on the surface of the protrusion and the inner surface end can be promoted, and the bonding surface can be further cleaned. Therefore, solid phase diffusion bonding can be performed under better conditions.

The reason why the inclination angle of the inclined outer surface with respect to the predetermined connecting axis is in the range of 5 to 80 ° is as follows. That is, when the inclination angle of the inclined outer surface with respect to the predetermined connection axis is smaller than 5 °, the contact angle between the protrusion and the inner surface end is too small, and the joint surface may not be cleaned well. In addition, with respect to the inclined outer surface, when the inclination angle with respect to the predetermined connection axis is larger than 80 °, the contact angle between the protruding portion and the inner surface end is too large, and the joint surface may not be cleaned well. . The lower limit of the tilt angle is more preferably 10 °, and further preferably 15 °. Further, the upper limit of the tilt angle is more preferably 50 °, and further preferably 30 °.
Although not described in detail, these numerical values are derived from experiments by the inventors of the present invention.

[5] In the method for manufacturing a pipe joined body according to the present invention, it is preferable that the predetermined connection axis is orthogonal to the central axis of the first metal pipe at the position where the through hole is located.

By adopting such a method, the first metal pipe and the second metal pipe can be combined relatively easily and firmly, and a stable pressure can be applied.

[6] In the method for manufacturing a pipe joined body according to the present invention, the first step includes a step of preparing a material pipe that is a material of the first metal pipe, and a step of forming the through hole in the material pipe. A step of forming a wall-like portion that is a source of the protruding portion around the through-hole by performing burring processing from the inside of the material pipe toward the outside, and the inclined outer surface on the outer surface of the wall-like portion And forming the wall-like portion as the protruding portion in this order.

By adopting such a method, it is possible to form a protrusion on an arbitrary metal pipe and prepare the first metal pipe.

As the burring process, various processing methods can be used as long as they can be applied to metal pipes. As an example, insert a jig with a slope that matches the inner diameter from one opening of a metal pipe with a through hole, insert a sphere larger than the through hole from the other opening, and press-fit the sphere with a rod-shaped body. Then, a method of processing to push up the periphery of the through-hole or a jig with an inclination matching the inner diameter is inserted from one opening of the metal pipe having the through-hole, and the tip can be bent from the other opening A method of processing by pressing the rod-shaped body and pushing up the periphery of the through-hole, a method of connecting a processing tool larger than the through-hole to the rod-shaped body inserted from the through-hole, and a method of processing by lifting the processing tool together with the rod-shaped body, The method of forming using a metal mold | die can be mentioned.

In the “step of forming the inclined outer surface on the outer surface of the wall-shaped portion and using the wall-shaped portion as the protruding portion”, various processing methods can be used as long as the inclined outer surface can be formed. For example, pressing using a mold, cutting, and rolling can be mentioned. In addition, when mass production is considered, it is preferable to use press working for the above-mentioned process from the relationship between processing accuracy and processing cost reduction.

The “wall-shaped portion” in this specification is “formed so as to surround the through hole and protrudes outward from the side surface of the first metal pipe”. That is, a wall-shaped part does not have an inclined outer surface among the requirements with which a protrusion part is provided.
About the protrusion part to form, it is preferable that the part which a protrusion part and an inner surface edge part should contact exists on the same plane. By setting it as such a method, it becomes possible to save the effort which processes the inner surface edge part of a 2nd metal pipe according to the side surface of a 1st metal pipe.

[7] In the method for manufacturing a pipe joined body according to the present invention, in the second step, the first metal pipe and the second metal pipe are combined and pressure is applied between the protruding portion and the inner surface end portion. It is preferable to carry out using a pressurizing apparatus capable of performing the above.

By adopting such a method, it is possible to perform solid phase diffusion bonding while maintaining a stable state in which pressure is applied between the first metal pipe and the second metal pipe.

As the pressurizing device, for example, a pressing device including a servo motor driven ball screw or an air cylinder can be suitably used.

[8] In the method for manufacturing a pipe joined body according to the present invention, it is preferable that the second step is performed using a pressurizing device including an electrode for performing the solid phase diffusion bonding as the pressurizing device.

By adopting such a method, it is possible to perform solid phase diffusion bonding without separately preparing an electrode.

[9] In the method for manufacturing a pipe joined body according to the present invention, the pressurizing device is fixed to the housing, a power supply device, a pressing device, a pair of electrodes connected to the power supply device, and the housing. A lower platen connected to one electrode of the pair of electrodes, and an upper platen connected to the other electrode of the pair of electrodes and capable of being pushed down toward the lower platen by the pressing device. It is preferable that the one electrode has a function of fixing the first metal pipe, and the other electrode has a function of fixing the second metal pipe.

By adopting such a method, the second step can be carried out continuously and stably, and as a result, the productivity of the pipe joined body can be further increased.

[10] In the method for manufacturing a pipe joined body according to the present invention, it is preferable that the second metal pipe is uniformly fixed over the entire circumference by the other electrode.

By adopting such a method, it is possible to stably fix the second metal pipe, and to flow a relatively uniform current through the entire second metal pipe, thereby performing more stable solid phase diffusion bonding. .

In order to uniformly fix the second metal pipe over the entire circumference, for example, the pressurizing device may include the other electrode of the collet chuck shape or the other electrode of the mold shape (on the inner surface side of the separable main body, It is preferable that a recess corresponding to the outer periphery of the two metal pipes is provided.

[10] In the above [10], it is preferable that the outer end portion of the first metal pipe is uniformly fixed over the entire circumference by one electrode rather than the presence of the protruding portion.

By adopting such a method, the first metal pipe can be stably fixed, and a relatively uniform current can be passed through the entire first metal pipe, so that solid phase diffusion bonding can be performed more stably. Become.

In order to uniformly fix the outer end portion of the first metal pipe over the entire circumference rather than the presence of the protruding portion, the pressurizing device is, for example, one electrode in the form of a collet chuck (both ends of the first metal pipe). A pair of two electrodes is preferable.) A recess corresponding to the outer periphery of the first metal pipe is provided on one of the mold-like electrodes (the inner surface side of the separable main body). Preferably).

[11] The pipe joined body of the present invention is a pipe joined body manufactured by the method for manufacturing a pipe joined body of the present invention, and the second metal pipe has a predetermined connecting shaft outside the side surface of the first metal pipe. The internal space of the first metal pipe and the internal space of the second metal pipe are connected together, and the residual stress at the joint between the first metal pipe and the second metal pipe Is a compressive stress.

Since the pipe joined body of the present invention is a pipe joined body manufactured by the method for manufacturing a pipe joined body of the present invention, the durability against corrosion and the durability against metal fatigue are higher than those of conventional pipe joined bodies. It is possible to achieve this, and it is possible to suppress a decrease in strength, and it is possible to obtain a pipe joined body capable of increasing productivity.

Due to the above-described effects, the pipe joined body of the present invention is suitable for parts used in fields that require a high degree of safety under severe environments exposed to long-term vibration and stress, such as automobile parts. It will be a thing.

[12] In the pipe joined body of the present invention, the joint has a tensile strength greater than the tensile strength of the base metal of the first metal pipe and the second metal pipe, and the joint has a deformation strength. The deformation strength of the base metal of the first metal pipe and the second metal pipe is preferably larger.

By adopting such a configuration, it becomes possible to sufficiently increase the reliability in a harsh environment exposed to long-term vibration and stress.

The “tensile strength” in the present specification is the strength when a certain object is pulled one-dimensionally (in the case of a pipe joined body, in the direction of separating the first metal pipe and the second metal pipe).
The “deformation strength” in this specification is the difficulty of deformation against external force such as impact.

It is a figure showing pipe zygote 100 concerning an embodiment. It is a figure showing the 1st metal pipe 10 in an embodiment. It is a figure which shows the 2nd metal pipe 20 in embodiment. It is a figure shown in order to demonstrate the 2nd process in an embodiment. It is a figure shown in order to demonstrate the 2nd process in an embodiment. It is a figure shown in order to demonstrate the 2nd process in an embodiment. It is a photograph which shows the pipe joined body 100a which concerns on an experiment example. It is a figure shown in order to demonstrate the mode of the junction part of the pipe conjugate | zygote 100a which concerns on an experiment example. It is a figure shown in order to demonstrate the result of having conducted the experiment regarding the tensile strength of the pipe joined body 100a which concerns on an experiment example. It is a figure shown in order to demonstrate the result of having conducted the experiment regarding the residual stress in the joint part vicinity of the pipe joined body 100a which concerns on an experiment example. It is a figure of the pipe zygote 102 concerning modification 1. It is a figure shown in order to explain the pipe zygote 104 concerning modification 2. It is a figure shown in order to demonstrate the manufacturing method of the conventional pipe zygote. It is a figure shown in order to demonstrate the manufacturing method of the conventional pipe zygote.

Hereinafter, a method for manufacturing a pipe joined body and an embodiment of the pipe joined body according to the present invention will be described.

[Embodiment]
First, the pipe joined body 100 according to the embodiment will be described.
Drawing 1 is a figure showing pipe zygote 100 concerning an embodiment. 1A is a perspective view of the pipe joined body 100, FIG. 1B is a top view of the pipe joined body 100, and FIG. 1C is a cross-sectional view taken along line A1-A1 of FIG. 1B. FIG. 1 (d) is a cross-sectional view taken along the line A2-A2 of FIG. 1 (b).

In FIG. 1, an axis parallel to the central axis ax1 of the first metal pipe 10 is an x axis, one axis perpendicular to the x axis is a y axis, and an axis perpendicular to the x axis and the y axis is a z axis. is doing. In the embodiment, since the central axis ax1 of the first metal pipe 10 intersects the central axis ax2 of the second metal pipe 20 perpendicularly, it can be said that the z-axis is an axis parallel to the central axis ax2. In other drawings displaying the x-axis, y-axis, and z-axis, each axis is the same as the corresponding axis in FIG.

The pipe joined body 100 according to the embodiment is manufactured by the “method for manufacturing a pipe joined body according to the embodiment” described later.
As shown in FIG. 1, the pipe joined body 100 includes a second metal pipe 20 joined to the outside of the side surface of the first metal pipe 10 along a predetermined connection axis, and the inside of the first metal pipe 10. The space 10i and the internal space 20i of the second metal pipe 20 are connected, and the stress remaining at the joint between the first metal pipe 10 and the second metal pipe 20 is a compressive stress (see an experimental example described later). is there.

In addition, the pipe joined body 100 has a tensile strength of the joint portion larger than that of the base metal of the first metal pipe 10 and the second metal pipe 20, and a deformation strength of the joint portion is the first metal pipe 10. And it is larger than the deformation strength of the base material of the second metal pipe 20 (refer to the experimental example described later).

The pipe joined body 100 is suitable for a part used in a field where a high level of safety is required under a severe environment exposed to vibration and stress for a long time such as an automobile part.

Next, the manufacturing method of the pipe joined body concerning an embodiment is explained.
FIG. 2 is a diagram illustrating the first metal pipe 10 according to the embodiment. 2A is a perspective view of the first metal pipe 10, FIG. 2B is a cross-sectional view of the first metal pipe 10 corresponding to FIG. 1C, and FIG. It is sectional drawing corresponding to FIG.1 (d) of the metal pipe 20. FIG.
Drawing 3 is a figure showing the 2nd metal pipe 20 in an embodiment. FIG. 3A is a perspective view of the second metal pipe 20, and FIG. 3B is a cross-sectional view of the second metal pipe 20 corresponding to FIG.

FIGS. 4 to 6 are diagrams for explaining the second step in the embodiment. 4 to 6, the left half is shown as a side view, and the right half as a cross-sectional view, with the line indicated by the symbol W as a boundary. Also, in FIG. 4 to FIG. 6, general components that are not related to the present invention are not shown.

In the manufacturing method of the pipe joined body according to the embodiment, the second metal pipe 20 is joined along the predetermined connection axis ax to the outside of the side surface of the first metal pipe 10, and the inside of the first metal pipe 10. This is a method for manufacturing the pipe joined body 100 in which the space 10 i and the internal space 20 i of the second metal pipe 20 are connected.
The method for manufacturing a pipe joined body according to the embodiment includes the first step S1 and the second step S2 in this order. Hereinafter, each step will be described.

First, the first step S1 will be described.
The first step S1 is a step of preparing the first metal pipe 10 and the second metal pipe 20. In the method for manufacturing a pipe joined body according to the embodiment, one first metal pipe 10 and one second metal pipe 20 are prepared.
Although not shown, the first step S1 is a step of preparing a material pipe as a material of the first metal pipe 10, a step of forming a through hole 12 in the material pipe, and from the inside of the material pipe to the outside. By performing the burring process, a step of forming a wall-like portion that is the basis of the protruding portion 14 around the through-hole 12, and an inclined outer surface 16 is formed on the outer surface of the wall-like portion, and the wall-like portion is formed into the protruding portion 14. Are included in this order.

As a burring process, various processing methods can be used as long as it is applicable to a metal pipe.
As long as the inclined outer surface can be formed, various processing methods can be used in the “step of forming the inclined outer surface on the outer surface of the wall-shaped portion and using the wall-shaped portion as the protruding portion”. In addition, when mass production is considered, it is preferable to use press working for the above-mentioned process from the relationship between processing accuracy and processing cost reduction.

As shown in FIG. 2, the first metal pipe 10 includes a through hole 12 and a protruding portion 14. The first metal pipe 10 is a pipe whose central axis ax1 is a straight line and whose section is circular.
The predetermined connection axis ax is orthogonal to the central axis ax1 of the first metal pipe 10.
As the metal material constituting the first metal pipe 10, for example, a steel material such as carbon steel can be used. However, any metal material can be used as long as solid-phase diffusion bonding using electrical resistance heat generation by energization as an energy source is possible. The metal material can be used.

The through hole 12 is a hole formed on the side surface of the first metal pipe 10.
The protrusion 14 is formed so as to surround the through-hole 12, has an inclined outer surface 16 that is inclined at a predetermined angle with respect to a predetermined connection axis ax, and extends outward from the side surface of the first metal pipe 10. Protruding. A portion where the protruding portion 14 and an inner surface end portion 22 to be described later should contact is on the same plane.
The inclined outer surface 16 has an inclination angle with respect to the predetermined connection axis ax within a range of 5 to 80 °, for example, 22 °.

As shown in FIG. 3, the second metal pipe 20 includes an inner surface end 22 that contacts the inclined outer surface 16 of the protrusion 14 when the first metal pipe 10 and the second metal pipe 20 are combined. The second metal pipe 20 is a pipe whose central axis ax2 is a straight line and whose section is circular.
As the metal material constituting the second metal pipe 20, for example, a steel material such as carbon steel can be used. However, any metal material can be used as long as solid phase diffusion bonding using electrical resistance heat generation by energization as an energy source is possible. The metal material can be used.

Next, the second step S2 will be described.
The second step S2 is performed using the pressure device 1000.

Here, the pressurizing apparatus 1000 will be briefly described.
The pressurizing device 1000 fixes the first metal pipe 10 and the second metal pipe 20 (see FIG. 4), and combines the first metal pipe 10 and the second metal pipe 20 with the projecting portion 14. It is possible to apply pressure between the inner surface end portion 22 (see FIG. 5). The pressurizing apparatus 1000 includes an electrode for performing solid phase diffusion bonding.

More specifically, the pressure device 1000 includes a housing (not shown), a power supply device (not shown), a pressing device (not shown), and a pair of electrodes 1010 connected to the power supply device. , 1012, a lower platen 1020 fixed to the casing and connected to one electrode 1010 of the pair of electrodes 1010, 1012, and connected to the other electrode 1012 of the pair of electrodes 1010, 1012 by a pressing device And an upper platen 1022 that can be pushed down toward the lower platen 1020. One electrode 1010 has a function of fixing the first metal pipe 10, and the other electrode 1012 has a function of fixing the second metal pipe 20.

The pressurizing apparatus 1000 includes one electrode 1010 having a mold shape (a concave portion corresponding to the outer periphery of the first metal pipe is provided on the inner surface side of the separable main body) as one electrode 1010. Further, the pressurizing apparatus 1000 includes the other electrode in a collet chuck shape as the other electrode 1012.
The pressurizing device 1000 includes a ball screw or an air cylinder driven by a servo motor as a pressing device.

Hereinafter, 2nd process S2 using the pressurization apparatus 1000 is demonstrated.
In the second step S2, as shown in FIGS. 4 to 6, after the second metal pipe 20 is combined with the first metal pipe 10 along the predetermined connection axis ax, the projecting portion 14, the inner surface end portion 22, In this step, the first metal pipe 10 and the second metal pipe 20 are joined by solid phase diffusion joining using an electric resistance heat generated by energization as an energy source while pressure is applied between them.

The second step S2 will be described in more detail as follows.
In the second step S2, first, the first metal pipe 10 is fixed to one electrode 1010, and the second metal pipe 20 is fixed to the other electrode 1012 (see FIG. 4). Next, the second metal pipe 20 and the other electrode 1012 are pushed down together with the upper platen 1022 by a pressing device, and the second metal pipe 20 is combined with the first metal pipe 10 (see FIG. 5). Next, a pressure (preload pressure) smaller than the “pressure applied between the protrusion 14 and the inner surface end 22 when performing solid phase diffusion bonding” (main pressure) is applied between the protrusion and the inner surface end. Hang in between (preload). Next, initial pressurization is performed immediately before energization for solid phase diffusion bonding. After that, the first metal pipe 10 and the second metal pipe 20 are joined by solid phase diffusion joining using electric resistance heat generated by energization as an energy source while continuing the pressurization from the initial pressurization.

In the first embodiment, one electrode 1010 fixes the outer end portion of the first metal pipe 10 more uniformly over the entire circumference than the protruding portion 14 exists, and the other electrode 1012 The second metal pipe 20 is fixed uniformly over the entire circumference.

The preload pressure can be set to an arbitrary pressure depending on the type of metal pipe to be used, and can be, for example, about 1/3 to 1/4 of the main pressure.

The pressure applied by the initial pressurization (initial pressurization pressure) can be the same as the main pressurization pressure, for example.
Specifically, the initial pressurization pressure is “when the initial pressurization is performed, the surface of the protrusion 14 and the inner surface 22 are substantially free from scraping of the impurity layer and the surface of the protrusion 14 and the inner surface after energization. The pressure at which the impurity layer on the surface of the end 22 is scraped occurs.
The initial pressurization time can be, for example, about 0.5 seconds.

In the second step S2, the energization time is set to 1 second or less. As a specific example, the energization time can be set to 0.25 seconds.
By completing the second step S2, the pipe joined body 100 can be manufactured.

Hereinafter, the manufacturing method of the pipe joined body and the effect of the pipe joined body according to the embodiment will be described.

According to the method for manufacturing a pipe joined body according to the embodiment, the fluid is divided by joining the second metal pipe to the outside of the side surface of the first metal pipe, as in the conventional method for producing a pipe joined body. Alternatively, it is possible to manufacture a pipe assembly to be joined.

In addition, according to the method for manufacturing a pipe joined body according to the embodiment, since the pipe joined body 100 is manufactured using solid-phase diffusion joining that uses electrical resistance heat generation by energization instead of melt joining, Since it does not occur and the deterioration of mechanical properties can be prevented, it is possible to increase the durability against corrosion and the durability against metal fatigue in the manufactured pipe joint compared to the method of manufacturing a pipe joint using fusion bonding. It becomes.

In addition, according to the method for manufacturing a pipe joined body according to the embodiment, since the pipe joined body 100 is manufactured using the solid phase diffusion joining, compressive stress remains in the joined portion (see an experimental example described later). From this point of view, it is possible to increase the durability against corrosion and the durability against metal fatigue in the manufactured pipe joined body as compared with the method for producing a pipe joined body using fusion joining.

Further, according to the method for manufacturing a pipe assembly according to the embodiment, since the pipe assembly 100 is manufactured using the solid phase diffusion bonding, it is not necessary to expose each metal pipe to a high temperature for a long time. Since it can prevent that the metal material which comprises comprises an annealing state, compared with the manufacturing method of the pipe joined body which uses brazing in a furnace, it becomes possible to suppress the strength fall in the manufactured pipe joined body.

In addition, according to the method for manufacturing a pipe joined body according to the embodiment, since there is no need to prepare a brazing metal or temporarily join a metal pipe, the process is compared with a pipe joined body using brazing in a furnace. Productivity can be increased from the viewpoint of number and cost.

For this reason, the manufacturing method of the pipe joined body according to the embodiment can increase the durability against corrosion and the durability against metal fatigue in the manufactured pipe joined body, compared to the manufacturing method of the conventional pipe joined body. In addition, it is possible to suppress a decrease in strength in the manufactured pipe joined body, and to provide a method for producing a pipe joined body capable of increasing productivity.

Moreover, according to the manufacturing method of the pipe joined body which concerns on embodiment, since the 1st metal pipe 10 provided with the protrusion part 14 is used, when aligning a 1st metal pipe and a 2nd metal pipe, it aligns easily. In addition, it is possible to manufacture a pipe joined body that is relatively strong against a force in a direction orthogonal to a predetermined connection axis.

In addition, according to the method for manufacturing a pipe joined body according to the embodiment, in order to apply pressure between the protruding portion 14 and the inner surface end portion 22, the impurity surfaces on the protruding portion surface and the inner surface end portion surface are shaved to join the bonding surface. Therefore, solid phase diffusion bonding can be performed under favorable conditions.

In the method for manufacturing a pipe joined body according to the embodiment, the second step S2 is after the first metal pipe 10 and the second metal pipe 20 are combined along the predetermined connection axis ax and the solid phase. Since the preload pressure is applied (preloaded) between the protruding portion 14 and the inner surface end 22 before the diffusion bonding is performed, the first metal pipe and the second metal pipe can be combined more stably. .

Moreover, according to the manufacturing method of the pipe joined body which concerns on embodiment, in 2nd process S2, in order to make electricity supply time into 1 second or less, heating time is shortened enough and a protrusion part and an inner surface edge part are comprised. It is also possible to prevent the metal material from being annealed, and as a result, it is possible to sufficiently suppress a decrease in strength near the joint.

Moreover, according to the manufacturing method of the pipe joined body according to the embodiment, in the second step S2, initial pressurization is performed immediately before energization for solid phase diffusion bonding, and pressurization is continued from the initial pressurization. Since the first metal pipe 10 and the second metal pipe 20 are joined by solid phase diffusion bonding, the contact between the protruding portion and the inner surface end portion is made good before the solid phase diffusion bonding is performed, and the protruding portion and inner surface end portion are formed. It is possible to allow a uniform current to flow.

Further, according to the method for manufacturing a pipe joined body according to the embodiment, the initial pressurization pressure is set to “when the initial pressurization is performed, the surface of the protrusion 14 and the inner surface end 22 is substantially free from abrasion. Therefore, it is possible to suppress damage to each metal pipe due to excessive application of the initial pressurizing pressure. In addition, solid phase diffusion bonding can be performed under sufficiently good conditions.

Further, according to the method for manufacturing a pipe joined body according to the embodiment, the inclined outer surface 16 has an inclination angle with respect to the predetermined connection axis ax within a range of 5 to 80 °, so that the contact between the inclined outer surface and the inner surface end portion is achieved. Since the angle is appropriate, the removal of the impurity layer on the surface of the protruding portion and the inner surface end portion is promoted, and the bonding surface can be further cleaned, so that solid phase diffusion bonding can be performed under better conditions. .

In addition, according to the method for manufacturing a pipe joined body according to the embodiment, the predetermined connection axis ax is orthogonal to the central axis ax1 of the first metal pipe 10 at the position where the through hole 12 is located. The two metal pipes can be relatively easily and firmly combined to apply a stable pressure.

Moreover, according to the manufacturing method of the pipe joined body which concerns on embodiment, 1st process S1 includes the process of preparing the raw material pipe used as the raw material of the 1st metal pipe 10, and the process of forming the through-hole 12 in a raw material pipe. , By performing burring from the inside of the material pipe to the outside, forming a wall-like portion that is the base of the protruding portion 14 around the through-hole 12, and forming the inclined outer surface 16 on the outer surface of the wall-like portion Then, since the step of forming the wall-shaped portion as the protruding portion 14 is included in this order, the protruding portion can be formed on an arbitrary metal pipe to prepare the first metal pipe.

In addition, according to the pipe joining method according to the embodiment, the protrusion 14 to be formed has a portion where the protrusion 14 and the inner surface end 22 should be in contact with each other on the same plane. It becomes possible to save the trouble of processing the first metal pipe in accordance with the side surface.

Moreover, according to the manufacturing method of the pipe joined body which concerns on embodiment, 2nd process S2 combines the 1st metal pipe 10 and the 2nd metal pipe 20, and applies a pressure between the protrusion part 14 and the inner surface edge part 22. FIG. Since it is performed using the pressurizing apparatus 1000 that can be applied, solid phase diffusion bonding can be performed while maintaining a stable state in which pressure is applied between the first metal pipe and the second metal pipe.

Moreover, according to the manufacturing method of the pipe joined body which concerns on embodiment, since 2nd process S2 is performed using the pressurization apparatus provided with the electrode for performing solid phase diffusion bonding as the pressurization apparatus 1000, an electrode is used. Solid phase diffusion bonding can be performed without preparing separately.

Moreover, according to the manufacturing method of the pipe joined body according to the embodiment, the pressurizing device 1000 includes a housing, a power supply device, a pressing device, a pair of electrodes 1010 and 1012, a lower platen, and an upper platen. One electrode 1010 has a function of fixing the first metal pipe 10, and the other electrode 1012 has a function of fixing the second metal pipe 20. Therefore, the second process is continuously and stably performed. As a result, it becomes possible to further increase the productivity of the pipe joined body.

In addition, according to the method of manufacturing a pipe assembly according to the embodiment, the second metal pipe 20 is uniformly fixed over the entire circumference by the other electrode 1012, so that the second metal pipe is stably fixed, In addition, a relatively uniform current is allowed to flow through the entire second metal pipe, so that more stable solid phase diffusion bonding can be performed.

Further, according to the method for manufacturing a pipe joined body according to the embodiment, one electrode 1010 fixes the outer end portion of the first metal pipe 10 uniformly over the entire circumference rather than the presence of the protruding portion 14. Therefore, the first metal pipe can also be stably fixed, and a relatively uniform current can be passed through the entire first metal pipe, so that solid phase diffusion bonding can be performed more stably.

Due to the above-described effects, the method for manufacturing a pipe assembly according to the embodiment is highly safe in a harsh environment exposed to vibration and stress for a long period of time, such as automobile parts (airbag system piping). This is a method suitable for manufacturing parts (pipe joints) used in fields that require high performance.

The pipe joined body 100 according to the embodiment is a pipe joined body manufactured by the method for manufacturing a pipe joined body according to the embodiment, and the stress remaining in the joint portion between the first metal pipe 10 and the second metal pipe 20. Because of the compressive stress, it is possible to increase the durability against corrosion and the durability against metal fatigue as compared with the conventional pipe joined body, and it is possible to suppress the strength reduction and to produce It becomes a pipe joined body which can raise the property.

Moreover, according to the pipe joined body 100 according to the embodiment, the tensile strength of the joint portion is larger than the tensile strength of the base metal of the first metal pipe 10 and the second metal pipe 20, and the deformation strength of the joint portion is the first. Since it is larger than the deformation strength of the base metal of the first metal pipe 10 and the second metal pipe 20, it is possible to sufficiently increase the reliability in a harsh environment exposed to long-term vibration and stress.

Due to the above-described effects, the pipe joined body 100 according to the embodiment is a part used in a field where a high level of safety is required under a severe environment exposed to vibration and stress for a long time, such as an automobile part. It will be suitable for.

[Experimental example]
FIG. 7 is a photograph showing a pipe joined body 100a according to an experimental example. Fig.7 (a) is the photograph which copied the pipe joined body 100a from the side surface side, and FIG.7 (b) is the photograph which copied the pipe joined body 100a from the diagonal.
FIG. 8 is a diagram for explaining the state of the joint portion of the pipe joined body 100a according to the experimental example. FIG. 8 (a) is a photograph of the pipe joined body 100a cut and the vicinity of the joint portion is copied. FIG. 8 (b) is an enlarged view of a part within the range indicated by the symbol A in FIG. 8 (a). FIG. 8C is a cross-sectional view for explaining FIG. 8B. In addition, the black dot in the coupling | bond part of Fig.8 (a) is the mark given after the cutting | disconnection of the pipe joined body 100a as a mark of a coupling | bonding interface. FIG. 8B is a photograph created by combining a plurality of photographs.

FIG. 9 is a diagram for explaining a result of an experiment regarding a tensile strength of the pipe joined body 100a according to the experimental example. FIG. 9A is a photograph of the pipe joined body 100a after the tensile test, and FIG. 9B is a graph (stress strain diagram) showing the result of the tensile test. The vertical axis of the graph shown in FIG. 9B indicates the tensile load (unit: kN), and the horizontal axis indicates the displacement (unit: mm).
FIG. 10 is a diagram for explaining the result of the experiment regarding the residual stress of the pipe joined body 100a according to the experimental example. FIG. 10A is a diagram for explaining a method for measuring residual stress, and FIG. 10B is a graph showing the result of the residual stress test. The vertical axis of the graph shown in FIG. 10B indicates the residual stress (unit: MPa), and the horizontal axis indicates the measurement position.

In the experimental example, the pipe joined body of the present invention (pipe joined body 100a according to the experimental example) was actually manufactured by the method for manufacturing a pipe joined body of the present invention, and the effect of the present invention was confirmed.
First, a method for manufacturing a pipe joined body according to an experimental example will be described.
The manufacturing method of the pipe joined body according to the experimental example is basically the same as the manufacturing method of the pipe joined body according to the embodiment. For this reason, only specific items are described in the experimental examples.

The pipe joined body 100a according to the example (not shown) is manufactured from the first metal pipe 10a and the second metal pipe 20a.
STKM-12 was used as the metal material constituting the first metal pipe 10a and the second metal pipe 20a.
As the metal pipe (material pipe) and the second metal pipe 20a that are the basis of the first metal pipe 10a, those having an outer diameter of 18.0 mm and an inner diameter of 14.8 mm were used. The maximum diameter of the protrusion in the first metal pipe 10a was 17.4 mm, and the inclination angle of the inclined outer surface with respect to the predetermined connection axis was 22 °.
Although the length of each metal pipe is not important in this experiment and is not strictly aligned, it is about 200 mm for the first metal pipe 10a and about 60 mm for the second metal pipe 20a.

In the experimental example, the pipe joined body 100a was manufactured using a pressurizing apparatus according to the pressurizing apparatus 1000 in the embodiment.
The initial pressurizing pressure and the main pressurizing pressure were 3.92 kN. The preload pressure was 1/3 of this pressurization pressure.
The initial pressurization time was 0.5 seconds.
In solid phase diffusion bonding using electrical resistance heat generation by energization as an energy source, the welding current was 15 kA, and the energization time was 0.25 seconds (15 cycles at 60 Hz).
By doing in this way, as shown in FIG. 7, the pipe joined body 100a which concerns on an experiment example was obtained.

First, in order to optically observe the state of the joining interface, the pipe joined body 100a was cut and observed. The cutting was performed so as to have the cross section shown in FIG. The cut surface is polished by a conventional method and then etched with 5% ethanol nitrate (nitral liquid) (see FIG. 8A. Note that reference numeral 12a indicates a through hole), and then magnified with a microscope. Observations were made. As a result, as shown in FIG. 8B, the portion where the first metal pipe 10a and the second metal pipe 20a are integrated and the projecting portion is in contact with the inner surface end (reference symbol C in FIG. 8B). It was observed that the bonding interface of the part indicated by From this observation, it was confirmed that the pipe joined body can be produced by the method for producing a pipe joined body of the present invention. Note that the fine gaps shown in FIG. 8B (see reference numerals B and D in FIG. 8B) are the protrusions when the first metal pipe 10a and the second metal pipe 20a are assembled. This is a gap remaining in a place where the inner surface end portion is not in contact (a place where the joining is not originally intended; see reference numerals B and D in FIG. 8C). For this reason, the strength or the like of the joint is not impaired by the fine gap.

Next, an experiment on tensile strength was performed. The experiment was conducted using SDW-9103 (manufactured by Imada Manufacturing Co., Ltd., maximum load 100 kN) which is a tensile / compression tester (autograph).
In the experiment, a load was applied in the direction of separating the first metal pipe 10a and the second metal pipe 20a using the same lot product of the pipe joined body 100a in which the appearance of the joining interface was observed. As a result, the joint did not break. Moreover, it has confirmed visually that the part which consists of a base material of each metal pipe has larger elongation by tension than a junction part (refer to Drawing 9 (a). Because it is after an experiment, a part of pipe joined body 100a) Is deformed.) The stress strain diagram is as shown in the graph of FIG. From this experiment, it was confirmed that the tensile strength of the joint was greater than that of the base material. In addition, since the same tendency as tensile strength exists also about deformation strength, it has also confirmed from the said experimental result that the deformation strength of a junction part is larger than a base material.

Next, an experiment on residual stress was performed. The experiment was performed using iXRD (produced by Proto Manufacturing Co., Ltd.) which is an X-ray stress measurement apparatus.
The experiment was performed using a sample collected from the pipe joined body 100a in which the appearance of the joining interface was observed. As a reference point (a point on the joining interface. More specifically, a point where the protruding portion and the inner surface end portion were in contact before joining) as a reference point (a point on the joining interface) as shown in the photograph of FIG. Measurement positions were set at intervals of 0.5 mm in the direction along the predetermined connection axis (up and down direction on the paper surface). The coordinate system was set with the second metal pipe side (upper side) positive from the reference point and the first metal pipe side (lower side) negative. As a result, as shown in FIG. 10B, the stress toward the second metal pipe remains on the first metal pipe side, and the stress toward the first metal pipe side remains on the second metal pipe side. It was confirmed that That is, it was confirmed that the stress remaining in the joint portion of the pipe joined body 100a (the pipe joined body according to the present invention) is a compressive stress.

As mentioned above, although this invention was demonstrated based on said each embodiment, this invention is not limited to said embodiment and experiment example. The present invention can be carried out in various modes without departing from the spirit thereof, and for example, the following modifications are possible.

(1) The dimensions, the number, the material, and the shape of each component described in the above-described embodiment and experimental example and illustrated in each drawing are exemplifications, and can be changed within a range that does not impair the effects of the present invention. .

(2) In the above embodiment, one first metal pipe 10 and one second metal pipe 20 are prepared and implemented, and the method for manufacturing a pipe assembly is implemented. It is not limited. FIG. 11 is a view of a pipe joined body 102 according to the first modification. 11A is a perspective view of the pipe joined body 102, and FIG. 11B is a cross-sectional view of the pipe joined body 102 corresponding to FIG. 1D. For example, as shown in FIG. 11, one first metal pipe (first metal pipe 10 in Modification 1) and a plurality of second metal pipes ( second metal pipes 20 and 40 in Modification 2) are prepared. And you may implement the manufacturing method of a pipe joined body. Further, a plurality of first metal pipes and a single first metal pipe may be prepared and executed, or a plurality of first metal pipes and a plurality of second metal pipes may be prepared and executed. Good.
When one or both of the first metal pipe and the second metal pipe are plural, the pipe joined body is formed by joining three or more metal pipes at a time (that is, in one second step). It may be manufactured. However, in this case, from the viewpoint of bonding reliability, the bonding of one first metal pipe and one second metal pipe is sequentially performed (that is, a total of n first metal pipes and second metal pipes). If there is a pipe, it is preferable to manufacture the pipe assembly by repeating the present invention n-1 times).

(3) The method for manufacturing a pipe joined body according to the present invention may be as in Modification 2 shown below. FIG. 12 is a view for explaining the pipe joined body 104 according to the second modification. 12A is a perspective view of the pipe joined body 104, FIG. 12B is a cross-sectional view corresponding to FIG. 1D of the pipe joined body 104, and FIG. 12C is a first metal pipe. FIG. 12D is a cross-sectional view corresponding to FIG. 1D of the first metal pipe 50. The manufacturing method of the pipe joined body according to Modification 2 is basically the same as the manufacturing method of the pipe joined body according to the embodiment, but the configuration of the first metal pipe prepared in the preparation process is different. The 1st metal pipe 50 in the modification 2 is provided with the receiving surface 58 which receives the end surface of the side with the inner surface edge part 22 of the 2nd metal pipe 20, as shown in FIG.12 (c) and (d). Reference numeral 50i denotes an internal space of the first metal pipe 50, reference numeral 52 denotes a through hole, reference numeral 54 denotes a protruding portion, and reference numeral 56 denotes an inclined outer surface. is there. The receiving surface 58 has a gap between the receiving surface 58 and the end surface of the second metal pipe 20 when the first metal pipe 50 and the second metal pipe 20 are combined. The surface 58 is formed at a position where the end surface is in contact. By adopting such a method, it is possible to eliminate the groove formed between the first metal pipe and the second metal pipe, and to further improve the appearance of the manufactured pipe assembly. When solid phase diffusion bonding is performed under the same conditions, the characteristics (residual stress, strength, etc.) of the bonded portion of the pipe bonded body remain unchanged regardless of the presence or absence of the receiving surface.

10, 10a, 30, 50 ... first metal pipe, 10i, 30i, 50i ... internal space of the first metal pipe, 12, 12a, 32, 52 ... through hole, 14, 54 ... projecting portion, 16, 56 ... inclined Outer surface, 20, 20a, 40 ... second metal pipe, 20i, 40i ... inner space of second metal pipe, 22 ... inner surface end, 58 ... receiving surface, 100, 102, 104 ... pipe assembly, 1000 ... pressurization Apparatus, 1010 ... One electrode, 1012 ... The other electrode, 1020 ... Lower platen, 1022 ... Upper platen, ax ... Predetermined connection axis, ax1 ... Central axis of the first metal pipe, ax2 ... Central axis of the second metal pipe

Claims (12)

1. A pipe in which a second metal pipe is joined along a predetermined connection axis to the outside of the side surface of the first metal pipe, and the internal space of the first metal pipe and the internal space of the second metal pipe are connected. A method for manufacturing a joined body, comprising:
   A through-hole formed in the side surface of the first metal pipe, and “having an inclined outer surface formed so as to surround the through-hole and inclined at a predetermined angle with respect to the predetermined connection axis; and When the first metal pipe provided with a projecting portion projecting outward from the side surface of the first metal pipe, and the first metal pipe and the second metal pipe are combined, they contact the inclined outer surface of the projecting portion. A first step of preparing the second metal pipe having an inner surface end;
   After combining the first metal pipe and the second metal pipe along the predetermined connection axis, electric resistance heat is generated by energization while applying pressure between the protrusion and the inner surface end. And a second step of joining the first metal pipe and the second metal pipe in this order by solid phase diffusion joining.
2. In the manufacturing method of the pipe zygote according to claim 1,
   In the second step, the energization time is set to 1 second or less, and the method for manufacturing a pipe joined body according to the second step.
3. In the manufacturing method of the pipe zygote according to claim 1 or 2,
   In the second step, initial pressurization is performed immediately before energization for the solid phase diffusion bonding, and the first metal pipe and the first metal are bonded by the solid phase diffusion bonding while continuing the pressurization from the initial pressurization. A manufacturing method of a pipe joined body characterized by joining two metal pipes.
4. In the method for manufacturing a pipe joined body according to any one of claims 1 to 3,
   The method of manufacturing a pipe joined body, wherein the inclined outer surface has an inclination angle with respect to the predetermined connection axis in a range of 5 to 80 °.
5. In the method for manufacturing a pipe joined body according to any one of claims 1 to 4,
   The method for manufacturing a pipe joined body, wherein the predetermined connection axis is orthogonal to a central axis of the first metal pipe at a position where the through hole is present.
6. In the method for manufacturing a pipe joined body according to any one of claims 1 to 5,
   The first step includes
   Preparing a material pipe as a material of the first metal pipe;
   Forming the through hole in the material pipe;
   Performing a burring process from the inside of the material pipe to the outside, thereby forming a wall-like portion that is a source of the protruding portion around the through hole; and
   Forming the inclined outer surface on the outer surface of the wall-shaped portion, and using the wall-shaped portion as the projecting portion in this order.
7. In the method for manufacturing a pipe joined body according to any one of claims 1 to 6,
   The second step is performed using a pressurizing device capable of applying pressure between the protruding portion and the inner surface end portion by combining the first metal pipe and the second metal pipe. To manufacture a pipe assembly.
8. In the manufacturing method of the pipe zygote according to claim 7,
   The second step is performed using a pressurizing device including an electrode for performing the solid phase diffusion bonding as the pressurizing device.
9. In the manufacturing method of the pipe zygote according to claim 8,
   The pressure device is
   A housing, a power supply device, a pressing device, a pair of electrodes connected to the power supply device, a lower platen fixed to the housing and connected to one of the pair of electrodes, and the pair An upper platen connected to the other of the electrodes and capable of being pushed down toward the lower platen by the pressing device,
   The one electrode has a function of fixing the first metal pipe;
   The other electrode has a function of fixing the second metal pipe.
10. In the manufacturing method of the pipe zygote according to claim 9,
    A method for producing a pipe joined body, wherein the other electrode is uniformly fixed over the entire circumference of the second metal pipe.
11. A pipe joined body manufactured by the method for manufacturing a pipe joined body according to any one of claims 1 to 10,
    A second metal pipe is joined along a predetermined connection axis to the outside of the side surface of the first metal pipe, and the internal space of the first metal pipe and the internal space of the second metal pipe are connected;
    The pipe joined body, wherein the stress remaining in the joint portion between the first metal pipe and the second metal pipe is a compressive stress.
12. In the pipe joined body according to claim 11,
    The tensile strength of the joint is greater than the tensile strength of the base metal of the first metal pipe and the second metal pipe, and the deformation strength of the joint is the first metal pipe and the second metal pipe. A pipe joined body characterized by being larger than the deformation strength of the base material.

Images