JP2009269035A - Friction pressure welding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a friction pressure welding method which prevents a burr from being generated at an outer surface of a joining part during friction pressure welding and enables a high joining strength not lower than the one at a part other than the joining part by simple pressure control. <P>SOLUTION: In the friction pressure welding method, a pressure welding part of a joining member having at least the hollow pipe-shaped pressure welding part 10 and a pressure welding part of a joining part having at least the solid rod-like pressure welding part 20 are pressed while being relatively rotated with each other in a state that they are mutually abutted, and the joining members are pressure welded by allowing the pressure welding parts to be softened and plastically deformed and turned into a liquid phase through the friction heat. The pipe-shaped pressure welding part 10 and the rod-like pressure welding part 20 are relatively rotated to be abutted with each other in a storage space 31 of a fixture 30 which has an inner diameter slightly larger than an outer diameter of the pipe shaped pressure welding part 10 and the rod-like pressure welding part 20 and has the storage space 31 having both ends that are opened. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is a method in which two joining members are butted against each other and rotated relative to each other for friction welding, and in particular, the pressure contact portion of one joining member is in the form of a hollow pipe, and the pressure contact portion of the other joining member The present invention relates to a friction welding method in which is a solid rod shape.

  There exists patent document 1 as this kind of friction welding method. In Patent Document 1, a hollow cylindrical pipe member made of a high melting temperature metal and a solid rod-shaped shaft member made of a low melting temperature metal are friction-welded with an auxiliary tool inserted into the cavity of the pipe member. ing. The auxiliary tool is made of a material that is not easily pressed against the shaft member and the pipe member. On the end face of the bar member, there is a projecting portion having a circular cross section formed so as to project concentrically with the end surface. In a state where the auxiliary tool is inserted in the cavity of the pipe member, when the protruding portion of the shaft member is accommodated in the cavity of the pipe member and the end surface around the protruding portion of the shaft member and the end surface of the pipe member are butted together, The end surface of the auxiliary tool and the tip end surface of the protruding portion do not contact each other, and a margin of a predetermined dimension is formed between both surfaces. Then, with the pipe member fixed in a non-rotatable manner, the shaft member is rotated around the axis while being pressed in the butting direction with the pressure P1. Then, the shaft member made of the low melting temperature metal is softened by the frictional heat generated by the rotation, so that the margin between the end surface of the auxiliary tool and the front end surface of the protruding portion is gradually reduced. At this time, the pipe member made of the high melting temperature metal is not deformed, and a burr is generated in which the shaft member is softened and deformed outward of the outer peripheral surface of the pipe member. Further, the shaft member is pressed as it is, and when the shift margin becomes a predetermined dimension or less, the shaft member is further pressed in the abutting direction with a pressure P2 larger than the pressure P1. Then, when the shift margin disappears, that is, when the end surface of the auxiliary tool and the tip surface of the protrusion come into contact with each other, the protrusion is softened by frictional heat generated between the end surface of the auxiliary tool and the tip surface of the protrusion. At this time, the auxiliary tool is not softened. When the protruding portion is sufficiently softened, the rotation of the shaft member is stopped, and the shaft member is pressed in the abutting direction with a pressure P3 larger than the pressure P2. Then, the softened projecting portion is dammed with an unsoftened auxiliary tool (becomes a dense pressure state), so that it is pressed against the inner peripheral surface of the pipe member that has not been softened. Finally, the auxiliary tool is removed from the cavity of the pipe member, and the two metal joining members are joined relatively firmly.

JP 2002-239753 A

  However, in the friction welding method described in Patent Document 1, the shaft member protrudes outside the outer peripheral surface of the pipe member, and so-called burrs are generated. This necessitates a burr removal step, and the productivity is poor. In addition, when the shaft member and the pipe member are abutted with each other, a margin is secured between the auxiliary tool and the protruding portion, and the pressing force of the shaft member is controlled in three steps based on the dimension of the margin. Yes. This complicates the pressure control for changing the pressing force of the shaft member in three stages. Furthermore, the shaft member and the pipe member can be joined relatively firmly by pressing the protruding portion softened by the auxiliary tool inserted into the cavity of the pipe member to the inner peripheral surface of the pipe member. Is made of a metal having a higher melting temperature than the shaft member, so that the pipe member does not soften during friction welding. Therefore, the pressure contact surface between the protrusion and the pipe member is a flat surface substantially parallel to the axial direction. Even if the shaft member and the pipe member can be pressure-bonded relatively firmly, the tensile strength of the joint portion (the portion where the pressure-contact portions of both joint members are joined) is small compared to the other portions, and the final product When an axial tensile stress acts on the joint, it tends to break at the joint, and there may be a problem in the tensile strength of the entire final product.

  Therefore, the present invention solves the above-mentioned problems, and the object is to prevent burrs from being generated on the outer surface of the joint during friction welding, and to achieve a level equal to or greater than that of parts other than the joint by simple pressure control. Provided is a friction welding method capable of obtaining a high bonding strength.

  The present invention provides a frictional heat that is pressed while rotating relative to each other in a state in which the pressure contact portions of at least a joining member having a hollow pipe-like pressure contact portion and at least a joining member having a solid rod-like pressure contact portion are in contact with each other. A friction welding method in which the pressure contact portion is pressed by softening plastic deformation or liquid phase, and the pipe pressure contact portion and the rod pressure contact portion are slightly smaller than the outer diameters of the pipe pressure contact portion and the rod pressure contact portion. A jig having a large inner diameter and having a housing space open at both ends is abutted in the housing space and relatively rotated.

  Here, the pressure contact portion of the joining member is a portion that is softened or liquidified by frictional heat and joined to the mating member. In addition, the metal joining member having at least a hollow pipe-shaped pressure contact portion includes a case where the whole is a hollow pipe shape, that is, a pipe member, and a case where only a part thereof is a hollow pipe shape. Similarly, the metal joining member having at least a solid bar-shaped pressure contact portion includes a case where the whole is a solid bar, that is, a bar member, and a case where only a part thereof is a solid bar. In addition, since the frictional heat is not directly generated between the jig and the joining member, the jig is not softened. Therefore, even if the pressure contact portions of both joining members are softened or liquid phase due to frictional heat, the outer peripheral surface is surrounded by a non-softened jig, so the soft or liquid phase pressure contact portions are radially outward. The occurrence of burrs is suppressed because there is no significant plastic deformation or flow.

  At this time, a projecting portion that can be inserted into the cavity of the pipe-shaped pressure contact portion is integrally formed on the end surface of the rod-shaped pressure contact portion, and the softening temperatures or melting points of the two joining members are equal to each other. Is preferred. The pipe-shaped press-contact portion is inserted into the cavity of the pipe member while an auxiliary tool made of a material having a softening temperature higher than that of the two joining members is inserted. The end surface of the pressure contact portion and the end surface of the rod-shaped pressure contact portion are abutted while rotating relative to each other, so that the end portion of the pipe-shaped pressure contact portion is softened or liquidified by frictional heat with the end surface of the rod-shaped pressure contact portion. The plastic deformation or flow inward in the radial direction, and the tip of the projecting portion is softened or liquidized by frictional heat with the end face of the auxiliary tool so as to be plastically deformed or flow outward in the radial direction. Is preferred.

  Even when two joining members having the same softening temperature or melting point are softened by frictional heat, the auxiliary tool is not softened by being made of a material having a softening temperature higher than that of the two joining members. In this state, when a pressing force is applied between the two joining members, each softened or liquid phase joined portion is surrounded by a jig and an auxiliary tool so that there is no escape space, The protrusions can only plastically deform or flow in opposite directions. That is, the end portion of the pipe-shaped pressure contact portion plastically deforms or flows toward the radially inward protruding portion side, and the tip portion of the protrusion portion plastically deforms or flows toward the radially outward pipe-shaped pressure contact portion side. At this time, the end of the pipe-shaped pressure contact portion is located on the side closer to the end surface of the rod-shaped pressure contact portion than the distal end portion of the protrusion portion, that is, the base end portion of the protrusion portion. However, it becomes a mechanical fitting state in which the hook is engaged between the tip portion of the projecting portion and the end surface of the rod-shaped press contact portion, and an anchor effect is obtained. As a result, the tensile strength at the joint is greatly improved, and is equal to or higher than the tensile strength at other portions. Therefore, even when an axial tensile stress acts on the final product, the joint does not break, so the tensile strength of the entire final product is improved, and a high-quality final product that is not easily damaged can be obtained.

  Further, when the end surface of the pipe-shaped pressure contact portion and the end surface of the rod-shaped pressure contact portion are brought into contact with each other, the tip surface of the protruding portion and the end surface of the auxiliary tool are in contact with each other, and the pipe-shaped pressure contact portion and the rod-shaped pressure contact The end portion of the pipe-like pressure contact portion, the end portion of the rod-like pressure contact portion, the tip end portion of the protruding portion, and the end surface of the auxiliary tool are both abutted by a first pressing force while relatively rotating the portion. After softening or liquid phase by mutual frictional heat, a second pressing force larger than the first pressing force is applied between the pipe-shaped pressure-contacting portion and the rod-shaped pressure-contacting portion to plastically deform them. It is preferable to make it flow. According to this, there is an advantage that the pressing force control is completed in two stages.

  According to the friction welding method of the present invention, almost no burrs are generated on the outer surface of the joint during friction welding, and high joint strength equal to or higher than that of parts other than the joint can be obtained by simple pressure control.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. However, the present invention is not limited thereto, and various modifications can be made without departing from the scope of the present invention. FIG. 1 is a process diagram of the friction welding method. Specifically, FIG. 1A shows a basic mounting state of the pipe member 10, the bar member 20, the jig 30, and the auxiliary tool 40, and FIG. 1B shows the pressing force P1 while rotating the bar member 20. FIG. 1 (C) shows a state in which the pipe member 10 and the projecting portion 22 are sufficiently softened, and then the pipe member 10 and the rod member 20 are connected to each other with a pressing force P2 larger than the pressing force P1. FIG. 1D shows a state of the joint 100 after the pipe member 10 and the rod member 20 are friction welded. FIG. 2 is an essential part enlarged view showing the plastic deformation state of the one end portion 11a of the softened pipe member 10 and the tip end portion 23a of the protruding portion 22 in the state shown in FIG. FIG. 3 is a perspective view of the jig 30.

  In the present embodiment, the hollow cylindrical pipe member 10 is used over the entire length as a joining member having at least a hollow pipe-like pressure contact portion, and the joining member having at least a solid rod-like pressure contact portion is provided over the entire length. A case where the solid cylindrical rod member 20 is used will be described. Referring to FIG. 1, the pipe member 10 has a predetermined length, and both ends thereof are open. The radial cross-sectional shape (inner surface shape) of the cavity 12 that is the internal space of the pipe member 10 is also circular. The rod member 20 also has a predetermined length and is solid over both ends thereof. The outer diameter of the pipe member 10 and the outer diameter of the rod member 20 are the same, and when the end surface 11 of the pipe member 10 and the end surface 21 of the rod member 20 are abutted, the outer peripheral surface of the pipe member 10 and the rod member It becomes flush with the outer peripheral surface of 20. Although details will be described later, the end surface 11 side end portion 11a of the pipe member 10 and the end surface 21 side end portion 21a of the rod member 20 serve as a joint portion joined by friction welding. On the end surface 21 of the bar member 20, a protruding portion 22 that protrudes a predetermined amount outward in the axial direction of the end surface 21 is integrally formed. The projecting portion 22 has a circular cross-sectional shape in the radial direction and is formed concentrically with the rod member 20. The outer diameter of the projecting portion 22 is slightly smaller than the inner diameter of the pipe member 10 (the diameter of the cavity 12), and is formed in a tapered shape that gradually decreases in diameter toward the distal end surface 23. The protrusion 22 can be formed integrally when the bar member 20 is cast or forged, or can be formed by cutting after manufacturing the bar member 20.

  The material of the pipe member 10 and the rod member 20 is not particularly limited as long as it is a material that is softened or liquefied by frictional heat and can be plastically deformed or fluidized by a pressing force, and metal materials, ceramics, resins, and the like can be used. Typically, aluminum, aluminum alloy, stainless steel, and the like. Other metal materials include cadmium, cobalt, magnesium, molybdenum, nickel, lead, niobium, cobalt, titanium, tungsten, vanadium, zirconium, silver, copper, and other alloy materials, carbon steel, alloy steel, and free-cutting steel. And steel materials such as maraging steel, and solder joints such as solder and solder. In the case of an active metal such as titanium, friction welding is preferably performed in an inert gas atmosphere. Examples of ceramics include fine ceramics such as silicon nitride ceramics, silicon carbide ceramics, alumina ceramics, and zirconia ceramics, and lacquer products such as ceramics, glass, cement, gypsum, and enamel. The synthetic resin is preferably a thermoplastic resin, such as polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polyvinyl acetate, ABS resin, AS resin, acrylic resin, polyamide (PA), Examples include polyacetal (POM), polycarbonate (PC), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polysulfone (PSF), and polyethersulfone (PES).

  The pressure contact combination of the pipe member 10 and the rod member 20 includes a combination of the same kind of metal, a combination of different kinds of metal, a combination of metal and ceramic, a combination of metal and resin, a combination of same kind of ceramics, a combination of different kinds of ceramics, and a combination of ceramics and resin. Any combination of a combination of the same resins, a combination of the same resins, and a combination of different resins is also possible. At this time, the bar member 20 is made of a material having a temperature equal to or higher than the softening temperature or melting point of the pipe member 10. Preferably, the softening temperature or the melting point of the pipe member 10 and the bar member 20 are set equal. If the pipe member 10 and the bar member 20 have the same softening temperature or melting point, they soften or become liquid phase almost simultaneously during friction welding, so that a high joining force can be easily obtained while shortening the processing time. In that sense, the pipe member 10 and the rod member 20 are preferably a combination of the same kind of metal, a combination of the same kind of ceramics, or a combination of the same kind of resin. Furthermore, the combination of the same kind or the same kind of metals is most preferable, for example, like joining of an aluminum material and an aluminum alloy material. Further, when either one or both of the pipe member 10 and the rod member 20 are brazing joint metal, the liquid phase brazing joint liquid film penetrates into the joining interface to increase the joining force, and also has airtightness and watertightness. Is effective.

  The jig 30 is a member that suppresses the generation of burrs on the outer surface of the joint portion 100 during friction welding, and is a block-like member having a cylindrical accommodation space 31 that is open at both upper and lower ends, as shown in FIG. . The jig 30 can be divided into two block bodies 30 a and 30 b at the center, and the two block bodies 30 a and 30 b are fastened by bolts 32. In other words, the jig 30 is composed of two block bodies 30a and 30b in which concave portions having a semi-cylindrical diameter are formed on one surface, and the concave portions of both the block bodies 30a and 30b are aligned with each other facing each other. As a result of the bolting, an accommodation space 31 composed of both concave portions is formed at the center.

  The inner diameter of the accommodation space 31 is slightly larger than the outer diameter of the pipe member 10 and the bar member 20, and when the pipe member 10 and the bar member 20 are accommodated (inserted) in the accommodation space 31, the pipe member 10 and the bar member 20 rotate. There is no clearance as close as possible, and there is no clearance that causes burrs between the pipe member 10 and the bar member 20 and the receiving space 31. That is, the pipe member 10 and the bar member 20 and the accommodation space 31 are close to each other. As described above, the jig 30 is not in close contact with the pipe member 10 or the bar member 20, and no large frictional heat is generated between the pipe member 10 or the bar member 20. Alternatively, a metal material or ceramic having a softening temperature equal to or higher than that of the bar member 20 may be used. However, it is preferable to use a material having a softening temperature higher than that of the pipe member 10 and the rod member 20 for the jig 30 so that the generation of burrs can be surely suppressed. In addition, a tapered surface 33 that gradually expands toward the upper surface is formed over the entire circumference of the accommodation space 31.

  Returning to FIG. 1 again, the auxiliary tool 40 includes a cylindrical insertion portion 41 and a base portion 42 that is integrally continuous with the lower end of the insertion portion 41. The outer diameter of the insertion portion 41 is basically one time smaller than the diameter of the cavity 12 of the pipe member 10 (the inner diameter of the pipe member 10). When the pipe member 10 or the rod member 20 is made of a material that becomes a liquid phase by frictional heat, the outer diameter of the insertion portion 41 is substantially equal to or slightly smaller than the inner diameter of the pipe member 10 so as to be in a liquid-tight state to some extent during pressure welding. It is preferable to set the degree. Further, the length of the insertion portion 41 is equal to or longer than the length of the pipe member 10 minus the protrusion amount of the protrusion portion 22 of the rod member 20. Preferably, the length is longer than the length of the pipe member 10. The shape of the base 42 is not particularly limited, and the outer diameter or the maximum dimension in the planar direction is larger than the outer diameter of the pipe member 10. The auxiliary tool 40 is not particularly limited as long as it is a material that has a softening temperature higher than that of the pipe member 10 and the rod member 20, is not easily pressed against both the members 10, 20, and has a strength that can withstand torque during friction welding. . For example, a magnesium alloy or hard ceramics can be used.

  Next, the friction welding procedure will be described. First, as shown in FIG. 1 (A), the pipe member 10 is fixed by standing up in a non-rotatable and non-movable state by the clamp device 50. At this time, one end (upper end) surface 11 of the pipe member 10 is fixed so as to be at an upper position lower than the vertical height dimension of the jig 30 from the upper surface of the clamp device 50. Next, both the block bodies 30a and 30b of the jig 30 are clamped from the outside of the pipe member 10 so that the pipe member 10 is accommodated in the accommodating space 31, and the jig 30 is mounted by fixing with bolts. Before and after mounting the jig 30, the insertion portion 41 of the auxiliary tool 40 is inserted into the cavity 12 from the other end (lower end) side of the pipe member 10, and the end face 43 of the auxiliary tool 40 and the pipe member 10 are At a position where the distance to the end surface 11 is equal to the protruding amount of the protruding portion 22 of the bar member 20, the rod member 20 is fixed in a non-rotatable and vertically stationary manner. This state is a basic mounting state in the friction welding method. In addition, it is preferable to wash | clean the pipe member 10, the bar member 20, the jig | tool 30, and the auxiliary tool 40 before mounting | wearing.

  When the pipe member 10 or the like can be mounted and fixed, the rod member 20 is abutted on the pipe member 10 coaxially from above at the first pressing force P1 while rotating at a predetermined rotational speed. The number of rotations of the bar member 20 may be appropriately adjusted according to the thickness of the pipe member 10, the outer diameters and materials (softening temperatures) of the pipe member 10 and the bar member 20, the protruding dimension of the protruding portion 22, and the like. As a guide, it is about 200 to 2000 rpm. On the basis of the peripheral speed, the speed is about 2 to 1000 mm / sec. Preferably, they are about 500-1500 rpm and about 50-800 mm / sec. The first pressing force is about 10 to 150%, preferably about 30 to 120%, of the yield strength or 0.5 yield strength of the pipe member 10 or the bar member 20 at room temperature.

  When the rod member 20 is lowered as it is and the protruding portion 22 is inserted into the cavity 12, the end surface 11 of the pipe member 10 and the end surface 21 of the rod member 20 are brought into contact with each other as shown in FIG. The front end surface 23 of the protrusion 22 and the end surface 43 of the auxiliary tool 40 are brought into contact with each other. At this time, a predetermined amount of clearance is formed between the pipe member 10 and the protruding portion 22. Since the tapered surface 33 is formed in the upper portion of the accommodation space 31, the rod member 20 can be smoothly inserted into the accommodation space 31. Further, since the outer surface of the bar member 20 and the inner surface of the housing space 31 of the jig 30 are not in close contact with each other, the bar member 20 can be rotated in the housing space 31 and the jig 30 can be rotated. Absent. As a result, frictional heat is generated at each abutting surface, and the end 11a of the pipe member 10, the end 21a of the bar member 20, and the tip 23a (see FIG. 2) of the protrusion 22 are softened or liquid phase, respectively. Turn into. In this sense, the first pressing force P1 can be said to be a friction load. At this time, since the rod member 20 and the jig 30 are not in close contact with each other and frictional heat is not directly generated, the jig 30 is not softened. Further, since the auxiliary tool 40 has a softening temperature higher than that of the rod member 20 (the protruding portion 22), it does not soften. Further, since the protruding portion 22 is formed in a tapered shape, the tip end portion 23a is easily softened or liquidified.

  When the end portions 11a, 21a, and 23a are sufficiently softened or liquid-phased, as shown in FIG. 1C, the rotation of the bar member 20 is stopped, and then the first pressing force is applied to the bar member 20. A second pressing force P2 larger than P1 is applied, and the rod member 20 is further pressed against the pipe member 10. Then, as shown in FIG. 2, the outer periphery of the joint portion 100 between the pipe member 10 and the rod member 20 is closely surrounded by a jig 30 that is not softened, so that the end portion 11a of the pipe member 10 has a diameter. Plastic deformation or flow toward the projecting portion 22 side in the direction. Thereby, it is suppressed that the burr | flash generate | occur | produces in the outer surface of the junction part 100 of the pipe member 10 and the bar member 20. FIG. At the same time, the distal end portion 23a of the protruding portion 22 is blocked by the end surface 43 of the auxiliary tool 40 that has not been softened, so that it plastically deforms or flows so as to expand toward the radially outward pipe member 10 side.

  In this sense, the second pressing force P2 can be said to be an upset load. The rotation stop of the bar member 20 and the timing for changing to the pressing force P <b> 2 may be appropriately set based on the passage of time, the amount by which the bar member 20 is lowered, and the like. The second pressing force P2 is preferably about 1.1 to 3.0 times the first pressing force P1. If the second pressing force P2 is smaller than 1.1 times the first pressing force P1, the softened metal or the like is difficult to be plastically deformed and the bonding strength may be reduced. On the other hand, if the second pressing force P2 is more than 3.0 times the first pressing force P1, a large driving force is required and the cost is increased, or the metal material or the like is deformed too much, and the bonding strength is reduced. The risk of doing so increases. More preferably, the second pressing force P2 is about 1.3 to 2.8 times the first pressing force P1, and even more preferably, the second pressing force P2 is 1. It is about 5-2.5 times.

  The end portion 11a of the pipe member 10 and the tip end portion 23a of the projecting portion 22 which have been plastically deformed or flowed within the clearance between the pipe member 10 and the projecting portion 22 while holding the pressing force P2 to the rod member 20 for a predetermined time. By being filled, the end portion 11a of the pipe member 10 is in good pressure contact with the end portion 21a and the protruding portion 22 of the rod member 20, and the tip end portion 23a of the protruding portion 22 is in good pressure contact with the pipe member 10. The At this time, since the rotation of the rod member 20 is stopped, the softened or liquid phase ends are securely and firmly pressure-bonded. Thereafter, when the auxiliary tool 40 is removed from the cavity 12 when sufficiently cooled, a product in which the pipe member 10 and the rod member 20 are firmly joined as shown in FIG. 1D is obtained. There is no burr on the outer surface of the joint 100 of the joined product, and the tensile strength of the joint 100 is not limited to the joint strength of the end face, but is also pulled by other parts due to the anchor effect by mechanical fitting. It is equal to or greater than the strength. The jig 30 and the auxiliary tool 40 can be used repeatedly.

(Example)
A 7N01 aluminum alloy pipe member and a 2014 aluminum rod member were friction-welded by the above-described method, and the cross-sectional structure of the obtained bonding material was observed and a tensile test was performed. FIG. 4 shows a cross-sectional photograph of the joint, and FIG. 5 shows an external appearance photograph of the fractured joint material after the tensile test.

The test conditions are as follows.
<Pipe member>
Outer diameter: 22 mm, inner diameter: 16 mm, thickness: 3 mm
<Bar material>
Outer diameter: 22mm
Outer diameter of protrusion: Base end; 14 mm, tip; 10 mm Protrusion: 10 mm
<Jig>
Material: S45C, accommodation space inner diameter: 22.1 mm
<Auxiliary tool>
Material: S45C, insertion part outer diameter: 15.8 mm
<Friction welding conditions>
Equipment: Friction welding machine manufactured by Nitto Seiki Co., Ltd. Speed: 2000rpm
First pressing force (friction load): 13000N
Second pressing force (upset load): 26000 N (twice the first pressing force)
<Tensile test>
The test was carried out based on JIS Z3121 No. 2 test piece.

  From the cross-sectional photograph of FIG. 4, according to the friction welding method of the present invention, it can be confirmed that the joint portion between the pipe member and the rod member is firmly pressed in a metallic structure in a mechanically fitted state. Moreover, from the fracture | rupture photograph of FIG. 5, the joining material obtained by the friction welding method of this invention was not fractured | ruptured in the junction part, but was fractured | ruptured in the other site | part. Therefore, it turns out that the tensile strength of a junction part is higher than the tensile strength of another site | part.

The breaking load in the tensile test was 42,600 N. The tensile strength was 238N / mm ^2, tensile strength 245 N / mm ² It is confirmed satisfy the following conditions defined in JIS H4100.

(Modification)
In the above embodiment, the end surface 11 of the pipe member 10 and the end surface 21 of the bar member 20 are in contact with each other, and at the same time, the tip surface 23 of the protruding portion 22 and the end surface 43 of the auxiliary tool 40 are in contact with each other. For example, when the pipe member 10 and the bar member 20 have different thermal conductivities and heat capacities, it is also preferable that the contact timings of the end surfaces 21 of the both bar members 20 and the tip surface 23 of the projecting portion 22 are different. Specifically, when the pipe member 10 has a higher thermal conductivity and heat capacity than the rod member 20 and is easily softened, before the end surface 21 of the rod member 20 contacts the end surface 11 of the pipe member 10, It is preferable to design the front end surface 23 so as to contact the end surface 43 of the auxiliary tool 40. On the other hand, when the bar member 20 has higher thermal conductivity and heat capacity than the pipe member 10 and is easily softened, the end surface 21 of the bar member 20 is brought into contact with the end surface 43 of the auxiliary tool 40 before the tip surface 23 of the protruding portion 22 abuts. Is preferably designed so as to abut against the end surface 11 of the pipe member 10.

  In the above embodiment, the pipe member 10 is fixed and only the rod member is rotated. However, as long as the pipe member 10 and the rod member 20 are relatively rotated, the present invention is not limited thereto, and the rod member 20 is fixed. The pipe member 10 may be rotated, or both the pipe member 10 and the rod member 20 may be rotated in opposite directions. Further, when the pipe member 10 is rotated, the auxiliary tool 40 is also rotated in the same direction as the pipe member 10 or in the opposite direction. At this time, the rotational speed of the pipe member 10 and the rotational speed of the auxiliary tool 40 may be the same or different.

  In the above embodiment, the case where the joining member is a pipe member that is hollow at both ends and a solid rod member that is at both ends has been described. As long as it is a joining member having a solid bar shape, the other parts may have any shape. The shape of the pressure contact portion may be an ellipse or a polygon in addition to a cylinder or a column. In the above-described embodiment, the protruding portion 22 is formed in a tapered trapezoidal shape. However, the protruding portion 22 is not limited to this, and may be a columnar shape or an inverted trapezoidal shape.

  In the above embodiment, the rotation of the rod member 20 is stopped and the second pressing force P2 is applied. However, the present invention is not limited to this, and the second pressing force P2 is applied while maintaining or reducing the rotation speed of the rod member 20. You may load.

It is process drawing of the friction welding method. It is a principal part enlarged view in the state shown in FIG.1 (C). 3 is a perspective view of a jig 30. FIG. It is a cross-sectional photograph of the joining material friction-welded. It is an external appearance photograph of the fractured bonding material after the tensile test.

Explanation of symbols

10 Pipe member (joining member)
11 End surface 11a of pipe member End 12 of pipe member 12 Cavity 20 Bar member 21 End surface 21a End of bar member (pressure contact portion)
22 Protruding portion 23 Protruding portion distal end surface 23a Protruding portion leading end portion 30 Jig 31 Accommodating space 40 Auxiliary tool 41 Inserting portion 43 Inserting portion end surface 100 Joining portion P1 First pressing force P2 Second pressing force

Claims (3)

In a state where the pressure contact portions of the joining member having at least a hollow pipe-like pressure contact portion and at least a joining member having a solid rod-like pressure contact portion are in contact with each other, they are pressed while being relatively rotated, and the pressure contact portion is caused by the frictional heat. It is a friction welding method for press-welding by softening plastic deformation or liquid phase,
The pipe-shaped pressure contact portion and the rod-shaped pressure contact portion are abutted in the storage space of a jig having a storage space having an inner diameter slightly larger than the outer diameter of the pipe-shaped pressure contact portion and the rod-shaped pressure contact portion and having both ends opened. A friction welding method characterized by being relatively rotated. On the end face of the rod-shaped pressure contact portion, a protrusion that can be inserted into the cavity of the pipe-shaped pressure contact portion is integrally formed to protrude,
The pipe-shaped pressure contact portion is inserted into the cavity of the pipe-shaped pressure contact portion while an auxiliary tool made of a material having a softening temperature higher than that of the two joining members is inserted into the cavity of the pipe-shaped pressure contact portion. The end surface of the rod and the end surface of the rod-shaped press contact portion are abutted while rotating relatively,
The end of the pipe-shaped pressure contact portion is softened or liquidified by frictional heat with the end surface of the rod-shaped pressure contact portion, and is plastically deformed or flows inward in the radial direction. 2. The friction welding method according to claim 1, wherein the friction welding method is characterized in that softening or liquid phase is caused by frictional heat with the end face of the metal to plastically deform or flow radially outward. When the end surface of the pipe-shaped pressure contact portion and the end surface of the rod-shaped pressure contact portion are brought together, the tip surface of the protruding portion and the end surface of the auxiliary tool are in contact with each other,
The pipe-shaped pressure-contact portion and the rod-shaped pressure-contact portion are abutted by a first pressing force while relatively rotating, and the end of the pipe-shaped pressure-contact portion, the end of the rod-shaped pressure-contact portion, and the tip of the protruding portion And the end face of the auxiliary tool and both of them are softened or liquid-phased by frictional heat between each other, and then a second pressing force larger than the first pressing force is interposed between the pipe-shaped pressure contact portion and the rod-shaped pressure contact portion. 3. The friction welding method according to claim 2, wherein both are plastically deformed or flowed by applying pressure.