JP5220449B2 - Method and apparatus for joining metal members - Google Patents

Description

  The present invention relates to a metal member joining method and apparatus for joining metal members together via a liquid phase.

  A spontaneously generated oxide film is present on the surface of a metal member made of an aluminum alloy or the like. Since it is not easy to join the metal members without removing the oxide film, it is common to perform the joining while removing the oxide film. That is, for example, nolock brazing method that removes oxide film with flux, vacuum brazing method that reduces oxide film in vacuum with Mg contained in brazing material, ion bombardment that removes oxide film by colliding with argon ions And an ultrasonic application method in which an ultrasonic wave is applied to destroy the oxide film (see Patent Document 1).

  Non-Patent Document 1 describes that members are pressed against each other at room temperature while causing relative slip between the members, thereby destroying the oxide film. Similarly, in Patent Document 2 and Non-Patent Document 2, it is also proposed to generate such a relative slip under heating. That is, Patent Document 2 describes joining a tube body made of a copper alloy and a tube body made of an aluminum alloy by this technique, while Non-Patent Document 2 describes an interface between members made of an aluminum alloy. It is disclosed that solid phase welding is performed while sliding under heat.

JP-A-6-7926 JP 2000-263250 A Ohashi Osamu et al. “Effects of Slip and Anodic Oxidation of Aluminum, Aluminum and Copper in Room Temperature Pressure Welding” Journal of the Japan Welding Society, Vol. 47, pages 294-299 Takeo Yokota et al. "Solid-phase Aluminum Welding by Interfacial Sliding" Proceedings of the Japan Welding Society, 1990, Vol. 8, pages 349-353

  As described in Non-Patent Document 2, when the relative slip is generated in the solid phase state without melting the metal member to be joined, the oxide film on the surface where the relative slip occurs is locally broken and clean. The metal is exposed. For this reason, as shown in FIG. 10, adhesion 3 occurs between the metal members 1 and 2. Also in the prior art described in Patent Document 2, adhesion 3 is generated in the same manner as described above because the metal member to be joined is provided with a relative slip in a solid state. Therefore, as described in Non-Patent Document 2 or Patent Document 2, it is necessary to apply an external force that can break the adhesion 3 in order to generate a relative slip at a place to be joined. Since a mechanism capable of applying a large external force is required, there is a problem that capital investment increases. In addition, when the adhesive force is strong, the member may be deformed.

  The present invention has been made to solve the above-described problems, and there is no occurrence of adhesion at the parts to be joined. For this reason, the equipment investment is reduced, and further, the concern that the members may be deformed may be eliminated. It is an object of the present invention to provide a method and apparatus for joining possible metal members.

In order to achieve the above object, a metal member joining method according to the present invention includes a first metal member and a second metal member between a first metal member and a second metal member. A process involving a low melting point brazing material,
The step of melting the brazing material and changing it into a liquid phase, and applying a stress to generate a relative slip between the first metal member and the second metal member with a slip amount of 0.5 mm or more. When,
Changing the liquid phase to a solid phase and joining the first metal member and the second metal member;
It is characterized by having.

  That is, in the present invention, adhesion of the first metal member and the second metal member is prevented by melting the brazing material and interposing the liquid phase, and the first metal member and the second metal. Lubricity is imparted between the members so that relative sliding easily occurs. For this reason, it is not necessary to apply a large external force.

  In other words, the present invention does not particularly require a mechanism for applying a large external force. Therefore, the capital investment is reduced. In addition, since a relative slip can be easily generated by applying a small external force, deformation of the metal member is also avoided.

  In addition, the oxide film is destroyed as the relative slip occurs in the liquid phase, and thereafter, the liquid phase becomes a protective film, so that the re-formation of the oxide film is also suppressed. Therefore, the joining easily proceeds even in the atmosphere.

  As described above, when the brazing material inserted between the metal members to be joined is melted and a relative slip occurs, when the slip distance (relative slip amount) becomes 0.5 mm or more, the entire joint surface is oxidized. The coating is destroyed, and for this reason, the joint has a strength comparable to that of the base material (metal member).

  A relative slip amount of 0.5 mm is sufficient, and an excessively large relative slip amount is accompanied by a large change in joint shape at the joint portion when joining metal members having small thicknesses. In order to avoid this, it is preferable to set the relative slip amount according to the thickness and shape of the first metal member and the second metal member.

  When the first metal member and the second metal member are brought into contact with each other and both end portions are joined to each other, a taper-shaped protrusion having a taper angle of 45 ° or more is formed at the end portion of one metal member in order to cause relative sliding. It is preferable to form a tapered concave portion having a shape corresponding to the shape of the tapered convex portion at the end of the remaining one metal member. In this case, the relative slip easily occurs when the tapered convex portion slides relatively along the tapered surface of the tapered concave portion.

  Alternatively, relative slip may be generated by relatively rotating the end face of one metal member along the end face of the remaining one metal member, or the end face of one metal member may be set to one of the remaining metal members. You may make it generate | occur | produce a relative slip by displacing along the extension direction of the end surface of a metal member.

  In any case, the step of melting the brazing material to generate a relative slip can be performed in the atmosphere, in a vacuum, or in an inert gas. When bonding is performed in the atmosphere, there is no need for a chamber for shielding the metal member from the atmosphere and an exhaust mechanism for exhausting the inside of the chamber. Therefore, there is an advantage that the capital investment is further reduced. On the other hand, when bonding is performed in a vacuum, the amount of air (oxygen), which is the source of the oxide film, is significantly reduced, making it more difficult to re-form the oxide film, which makes relative sliding easier. The advantage is obtained.

Further, the metal member joining apparatus according to the present invention is interposed between the first metal member and the second metal member, and has a lower melting point than the first metal member and the second metal member. Heating means for heating and melting the material;
Stress applying means for generating a relative slip between the first metal member and the second metal member;
It is characterized by having.

  With such a configuration, it becomes easy to melt the brazing material and cause relative slip, and as a result, it is possible to easily obtain a joint having a strength comparable to that of the base material.

  The stress applying means may be either a means for applying pressure in the compression direction, a means for applying a force for displacing in the rotational direction, or a means for applying a force for moving in a straight line.

According to the present invention, a brazing material having a low melting point is inserted between metal members to be joined, and the brazing material is melted into a liquid phase between the metal members. Relative slip is generated. Since the relative slip easily occurs due to the liquid phase intervening, a mechanism for applying a large external force becomes unnecessary, and the capital investment is reduced. Moreover, since it is not necessary to apply a large external force, the concern that the metal member is deformed is also eliminated.

  In addition, since the oxide film is destroyed by the occurrence of relative slip, it is possible to easily obtain a joint having high joint strength.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a metal member joining method according to the present invention will be described in detail with reference to the accompanying drawings by giving preferred embodiments in relation to a joining apparatus for carrying out the method.

  FIG. 1 is a main part schematic configuration diagram schematically showing a bonding apparatus 10 according to the present embodiment. The bonding apparatus 10 includes a first electrode 14 and a second electrode 16 that are electrically connected to a power source 12.

  The first electrode 14 is positioned and fixed on the pedestal 18 so as to face upward in FIG. The first electrode 14 is electrically connected to the positive electrode of the power supply 12 via the lead wire 20.

  On the other hand, the second electrode 16 having substantially the same configuration as the first electrode 14 is disposed so as to face the first electrode 14. Further, the second electrode 16 is positioned and fixed to a wide end portion 25 that constitutes a rod 24 of a hydraulic cylinder 22 (stress applying means) that applies a stress as a compressive force. That is, the second electrode 16 approaches and separates from the first electrode 14 as the rod 24 moves forward and backward.

  The second electrode 16 is electrically connected to the negative electrode of the power source 12 by a lead wire 26. FIG. 1 shows a state where an electrically closed circuit is formed.

  A first tubular body 32 and a second tubular body 34 are interposed between the first electrode 14 and the second electrode 16 via carbon spacers 28 and 30. In this case, both the first tubular body 32 and the second tubular body 34 are made of an aluminum alloy having an alloy number 6063 (JIS). In the following description, it is simply expressed as “6063 aluminum alloy”. The “4104 aluminum alloy” described later has the same meaning.

  FIG. 2 shows an end portion of the first tubular body 32 facing the second tubular body 34 and an end portion of the second tubular body 34 facing the first tubular body 32. As can be seen from FIG. 2, a tapered recess 36 is formed at the end of the first tubular body 32 by being reduced in diameter from the outer diameter side toward the inner diameter side. At the end of the second tubular body 34, a tapered convex portion 38 that protrudes while being reduced in taper is formed. The shape of the tapered concave portion 36 corresponds to the shape of the tapered convex portion 38. Therefore, when the tapered convex portion 38 is inserted into the tapered concave portion 36, the tapered surfaces 40 and 42 are in close contact with each other.

  Of course, the taper angle θ1 of the tapered concave portion 36 and the taper angle θ2 of the tapered convex portion 38 are set to satisfy θ1 = θ2. Here, θ1 and θ2 are preferably set to 45 ° or more. This is because, as will be described later, relative slip where the slip amount between the first tube body 32 and the second tube body 34 is 0.5 mm or more easily occurs.

  Such joining of the first tubular body 32 and the second tubular body 34 is performed as follows.

  First, the tapered convex portion 38 of the second tubular body 34 is inserted into the tapered concave portion 36 of the first tubular body 32 and placed on the first electrode 14 in this state.

  Here, when the tapered convex portion 38 is inserted into the tapered concave portion 36, the shape of the tapered surfaces 40, 42 is formed between the first tubular body 32 and the second tubular body 34 as shown in FIG. A brazing material 44 having a shape corresponding to the above is interposed. As the brazing material 44, a metal having a low melting point is selected as compared with 6063 aluminum alloy which is a material of the first tube body 32 and the second tube body 34. A suitable example of this type of metal is 4104 aluminum alloy. The solidus temperature and liquidus temperature of 6063 aluminum alloy are 615 ° C. and 655 ° C., respectively, and the solidus temperature and liquidus temperature of 4104 aluminum alloy are 559 ° C. and 591 ° C., respectively.

  Next, the hydraulic cylinder 22 is energized, and its rod 24 moves forward downward. As a result, as shown in FIG. 1, the first tube body 32 and the second tube body 34 are pressed by the first electrode 14 and the second electrode 16 through the carbon spacers 28 and 30, and the electric Thus, a closed circuit is formed.

  Thereafter, a current i is supplied from the power source 12. This current i returns to the power supply 12 via the carbon spacer 28, the first electrode 14, the first tube 32, the brazing material 44, the second tube 34, the second electrode 16, and the carbon spacer 30. That is, the first tube body 32, the brazing material 44, and the second tube body 34 are energized, and the temperature of the first tube body 32, the brazing material 44, and the second tube body 34 increases accordingly.

  The current i is set to a value at which the brazing material 44 can be melted. That is, the brazing filler metal 44 is melted by supplying the current i flowing from the first electrode 14 to the second electrode 16. As a result, as shown in FIG. 4, the liquid phase L is interposed between the tapered surfaces 40 and 42 of the first tubular body 32 and the second tubular body 34. For this reason, the occurrence of adhesion between the tapered surfaces 40 and 42 is avoided.

  Moreover, the liquid phase L assists that the 1st pipe body 32 and the 2nd pipe body 34 displace relatively by providing lubricity. Therefore, even when the pressing force applied to the first tubular body 32 and the second tubular body 34 is small, the tapered surface 40 of the tapered convex portion 38 has a tapered concave portion 36 as shown in FIG. It is easily displaced along the tapered surface 42. That is, relative slip occurs easily. For this reason, it is not necessary to install a cylinder or the like that can apply a large pressing force, so that the capital investment is reduced. Moreover, since adhesion does not occur, the concern that the first tubular body 32 or the second tubular body 34 is deformed can be eliminated. When the relative displacement amount (slip amount) LS between the tapered surface 40 of the tapered convex portion 38 and the tapered surface 42 of the tapered concave portion 36 is 0.5 mm or more, the joint efficiency is large at the time of joining described later. Become. Here, the joint efficiency is a percentage of the strength of the joint with respect to the strength of the first tubular body 32 (or the second tubular body 34) that is the base material.

  As the relative slip occurs, the oxide film existing on the tapered surface 40 in the tapered concave portion 36 of the first tubular body 32 and the tapered surface 42 in the tapered convex portion 38 of the second tubular body 34 is destroyed. . That is, the 6063 aluminum alloy is exposed on the tapered surfaces 40 and 42.

  Elements are diffused into the brazing filler metal 44 from the tapered surfaces 40 and 42 exposed by the 6063 aluminum alloy. At the same time, element diffusion from the brazing material 44 to the tapered surfaces 40 and 42 also occurs. As a result, the tapered surfaces 40 and 42 are metallicly joined to the brazing material 44.

  As described above, according to the present embodiment, by causing the liquid phase L to intervene between the first tubular body 32 and the second tubular body 34, relative slip is likely to occur, and relative slip is generated. The oxide film is destroyed. Since this process proceeds even in the atmosphere, it is possible to perform all the joining operations in the atmosphere.

  Here, usually, when joining members made of metals that easily form a spontaneous oxide film such as an aluminum alloy in the atmosphere, a new oxide film is immediately formed even if the oxide film is removed. End up. However, in the present embodiment, since the liquid phase L also functions as a protective film, it is difficult to re-form the oxide film. Even if the oxide film is re-formed, the relative slip is progressing, so that the oxide film can be destroyed immediately.

  Therefore, as can be understood from FIG. 1, it is not particularly necessary to attach a chamber, an exhaust line, or the like to the bonding apparatus 10. This also contributes to lower capital investment.

  As the pressing of the hydraulic cylinder 22 is stopped, the relative slip is finished and the energization is stopped. Thereafter, the liquid phase L is solidified by being left for a predetermined time, and the first tubular body 32 and the second tubular body 34 are joined via the brazing filler metal 44. As described above, since the tapered surfaces 40 and 42 in a state where the oxide film is destroyed by the relative slip are joined together, the first tubular body 32 and the second tubular body 34 after joining exhibit excellent joint efficiency.

  In the above-described embodiment, a tubular body (cylindrical body) is illustrated, and a case where a tapered concave portion 36 and a tapered convex portion 38 are provided in each of the first tubular body 32 and the second tubular body 34 is illustrated. However, even when solid cylindrical bodies are joined together or when hollow or solid polygonal bodies are joined together, a tapered concave portion 36 and a tapered convex portion 38 are provided for each, and joined according to the above. You may make it do.

  Further, the relative slip is not limited to the slip that occurs along the tapered surfaces 40 and 42 shown in FIG. 5, and the solid cylindrical bodies 50 and 52 are illustrated as shown in FIGS. 6A and 6B. It may be a slip that occurs in the direction of rotation. Alternatively, as shown in FIGS. 7A and 7B exemplifying the solid rectangular parallelepipeds 54 and 56, the sliding may be performed along the extending direction of the end face. Of course, in these cases, a joining apparatus having a mechanism for causing relative sliding in the rotational direction and a mechanism for displacing along the extending direction of the end surface is used.

  Further, in the above-described embodiment, the bonding is performed in the atmosphere. However, an exhaust mechanism such as a chamber surrounding the second electrode 16 from the first electrode 14 and a pump for discharging the gas in the chamber is provided. You may make it attach to a joining apparatus and to make it join under vacuum pressure reduction. In this case, since the amount of oxygen for re-forming the oxide film is reduced, relative slip occurs more easily, and there is an advantage that the slip amount is increased and the joint efficiency is improved.

  Furthermore, an inert gas supply line for supplying an inert gas such as argon may be provided in the chamber, and bonding may be performed in an inert gas atmosphere.

  And the metal member which joins is not specifically limited to an aluminum alloy, For example, what consists of a metal in which an oxide film is formed in the surface, such as a copper alloy and a steel material, should just be used. In addition, the metal seed | species from which to-be-joined objects differ may be sufficient. In other words, the present invention can also be applied when different kinds of metals are joined together.

  In this embodiment, the brazing material 44 is heated by energizing the first tube body 32 and the second tube body 34. For example, other heating methods such as high-frequency induction heating are used. Of course, can be adopted.

  Two pipe bodies 32, 34 made of 6063 aluminum alloy and having an inner diameter of 40 mm, an outer diameter of 50 mm, and a length of 25 mm are prepared, and as shown in FIG. 2, a tapered recess 36 is provided in one of these, A taper-shaped convex portion 38 was provided on the remaining one. The taper angles θ1 and θ2 of the tapered concave portion 36 and the tapered convex portion 38 were variously changed as shown in FIG. Then, a brazing material 44 made of 4104 aluminum alloy and having a thickness of 0.1 mm is interposed between the tapered concave portion 36 and the tapered convex portion 38 so that the tapered convex portion 38 is formed with respect to the tapered concave portion 36. Inserted.

  The tube bodies 32 and 34 in this state were set in the joining apparatus 10 shown in FIG. Next, the tube bodies 32 and 34 are pressed with a pressure of 0.7 MPa by the first electrode 14 and the second electrode 16 of the bonding apparatus 10 and measured by a K-type thermocouple attached by spot welding in the vicinity of the bonding interface. The joining temperature was 575 ° C. and energization was performed in the atmosphere. Thereby, the brazing filler metal 44 was melted. Note that the temperature was increased to about 50 ° C./min until the bonding temperature, and the bonding temperature was maintained for 5 minutes.

  Then, by allowing to cool for a predetermined time, the molten brazing material 44 was solidified and the tubes were joined together. Each is referred to as Examples 1-5.

  Further, the pipes were joined in accordance with the above except that the joining temperature was 600 ° C. Each is designated as Examples 6-10.

  Further, the tubular bodies were joined after the taper angles θ1, θ2 were 45 °, the joining temperature was 600 ° C., and the pressing force was 1.5 MPa. This is Example 11.

  For comparison, the tubular bodies were joined according to Examples 1 to 5 except that joining was performed without interposing the brazing filler metal 44 between the tapered recess 36 and the tapered protrusion 38. Each is designated as Comparative Examples 1-5.

  About the pipe bodies 32 and 34 after joining in the above Examples 1-11 and Comparative Examples 1-5, the slip amount (refer FIG. 5) in a joining surface was measured. Moreover, the tensile test was done with respect to the joined pipe bodies 32 and 34, and the joint efficiency which remove | divided the joining strength of the joined pipe bodies 32 and 34 by the intensity | strength of 6063 aluminum alloy was calculated | required. The results are shown in FIG. 8 as a chart in relation to the taper angles θ1 and θ2. It can be understood from FIG. 8 that the taper angles θ1 and θ2 are 45 ° or more and it is easy to obtain a slip amount of 0.5 mm or more by interposing the brazing filler metal 44 and the joint efficiency is improved. .

  Moreover, since Examples 1 to 11 were performed in the air, it is clear that a joined body having a joining strength equivalent to that of a seamless 6063 aluminum alloy can be obtained even in the air.

  On the other hand, in Comparative Examples 1-5, the slip amount is 0, and it is recognized that no relative slip has occurred. In this case, the joint efficiency was also extremely small.

  Furthermore, the tubular bodies were joined to each other in accordance with Examples 1 to 5 except that a vacuum apparatus was used under a vacuum pressure of 5 Pa, using a joining device having a chamber and an exhaust mechanism. Each is designated as Examples 12-16.

  For comparison, in accordance with Examples 12 to 16 except that the joining was performed with a pressing force of 0.5 MPa without interposing the brazing material 44 between the tapered concave portion 36 and the tapered convex portion 38. The tube was joined. Let each be the comparative examples 6-10.

  For the tube bodies after joining in Examples 12 to 16 and Comparative Examples 6 to 10 described above, the joint efficiency was determined while measuring the amount of slip on the joint surface. The results are shown in FIG. 9 as a chart in relation to the taper angles θ1 and θ2. If Example 12-16 and Comparative Examples 6-10 are contrasted with reference to FIG. 9, even when joining in a vacuum, taper angle (theta) 1 and (theta) 2 will be 45 degrees or more and brazing material 44 will be interposed. By doing so, it becomes easy to obtain a slip amount of 0.5 mm or more, and it is clear that joint efficiency is greatly improved.

  Moreover, when Examples 1-5 and Examples 12-16 are compared, when joining in a vacuum, it turns out that a relative slip amount becomes large compared with the case where it joins in air | atmosphere on the same conditions. From this point of view, it can be said that it is advantageous to perform the joining in a vacuum from the viewpoint of improving the joint efficiency.

It is the principal part schematic block diagram which showed typically the joining apparatus which concerns on this Embodiment. It is principal part expansion explanatory drawing which shows the edge part of the tubular body joined by the joining apparatus of FIG. It is a principal part expansion perspective view which shows the state by which the brazing material was interposed between the 1st tubular body and the 2nd tubular body. It is principal part expanded sectional explanatory drawing which shows the state which the liquid phase intervened between the taper surfaces of a 1st tubular body and a 2nd tubular body. It is principal part expanded sectional explanatory drawing which shows the state which raise | generated the relative slip of the 1st tubular body and the 2nd tubular body. 6A and 6B are enlarged explanatory views of main parts for explaining a state in which relative slip occurs in a direction different from that in FIG. FIGS. 7A and 7B are enlarged explanatory views of main parts for explaining a state in which relative slip occurs in a direction different from those in FIGS. 5, 6A, and 6B. It is a graph which shows the relationship between the taper angle of the pipe bodies joined in air | atmosphere in Examples 1-11 and Comparative Examples 1-5, relative slip amount, and joint efficiency. It is a graph which shows the relationship between the taper angle of the pipe bodies joined in the vacuum in Examples 12-16 and Comparative Examples 6-10, relative slip amount, and joint efficiency. It is principal part expanded sectional explanatory drawing which shows the state which adhesion produced between to-be-joined objects when the relative slip was generated in the solid-phase state.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Joining device 12 ... Power supply 14, 16 ... Electrode 22 ... Hydraulic cylinder 32, 34 ... Tube 36 ... Tapered recessed part 38 ... Tapered convex part 40, 42 ... Tapered surface 44 ... Brazing material 50, 52 ... Cylindrical body 54 56 ... rectangular parallelepiped L ... liquid phase

Claims (3)

Interposing a brazing material having a melting point lower than that of the first metal member and the second metal member between the first metal member and the second metal member;
The brazing material is melted and changed into a liquid phase, and stress is applied to generate a relative slip between the first metal member and the second metal member with a slip amount of 0.5 mm to 4 mm. A process of
Re-forming the brazing material by changing the liquid phase to a solid phase, and joining the first metal member and the second metal member via the brazing material;
Have
When both end portions of the first metal member and the second metal member are butted against each other, a tapered convex portion having a taper angle of 45 ° or more is formed at the end portion of one metal member, Further, a tapered concave portion having a shape corresponding to the shape of the tapered convex portion is formed at an end portion of the remaining one metal member, and the tapered convex portion is relatively moved along the tapered surface of the tapered concave portion. A method for joining metal members, characterized by causing a relative slip by sliding.   The joining method according to claim 1, wherein the step of melting the brazing material to generate a relative slip is performed in the air, in a vacuum, or in an inert gas. . After the first metal member and the second metal member are interposed between the first metal member and the second metal member, the brazing material having a melting point lower than that of the first metal member and the second metal member is melted and changed into a liquid phase. A metal member joining apparatus for re-forming a brazing material by changing the liquid phase to a solid phase and joining the first metal member and the second metal member via the brazing material. And
Formed at an end portion of the first metal member and the second and the tapered shaped convex portions taper angle formed at the end is more than 45 ° of one of the metallic member of the metal member, the remainder of the one of the metal member has been melted by heating before Symbol brazing material interposed between the tapered recess of a shape corresponding to the shape of the tapered shaped convex portion, a heating means for said liquid phase,
When the liquid phase is obtained, the tapered convex portion slides relatively along the tapered surface of the tapered concave portion, thereby sliding between the first metal member and the second metal member. Stress applying means for generating a relative slip of an amount of 0.5 mm or more and 4 mm or less;
An apparatus for joining metal members, comprising:

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