JP2006205190A - Method of joining dissimilar metals - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of joining dissimilar metals capable of obtaining a high joining strength by increasing the area of breakage of a facing oxide film on a work surface in joining dissimilar metals by a diffusion bonding method using a friction stirring and joining method, and to provide a dissimilar metal joining method capable of preventing degradation of the joining strength by preventing the reduction of the thickness of a work at a joined portion as much as possible. <P>SOLUTION: In the method of joining dissimilar metals, a second member 2 consisting of a metal different from that of a first member 1 overlaps the first member 1 having recesses 11, 12 from opening part sides of the recesses 11, 12 of the first member 1, and the first member 1 is joined with the second member 2 by pressing the second member 2 against inner faces of the recesses 11, 12 of the first member 1 while stirring the second member by the rotation of a rotary tool 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for joining dissimilar metal materials, and more particularly, to a method for joining dissimilar metal materials by diffusion bonding using a friction stir technique.

  Conventionally, various steel materials such as carbon steel, alloy steel, stainless steel, and heat-resisting steel have been used for automobiles and railway vehicles. However, aluminum and magnesium are used as metal materials for members to reduce vehicle weight. Light nonferrous light metals such as these are often used. Therefore, in manufacturing a vehicle or the like, it is necessary to join different metal materials such as an iron-based metal and a light metal.

  As joining methods for dissimilar metal materials, conventionally, joining by methods such as arc welding and laser welding has been attempted. However, in these welding methods, generally, the welding temperature is high, and the dissimilar metal materials are separated from those materials. It has been pointed out that a portion made of a brittle intermetallic compound or alloy is generated, and the bonding strength between the materials is weakened. In addition, these methods have a problem that the workpiece is deformed or the cost is increased.

  As a method for overcoming such problems, studies are being made to apply the friction stir welding method to the joining of dissimilar metal materials. Here, the friction stir welding method refers to, for example, pressing a cylindrical tool having a small protrusion called a joining pin at the tip against a pair of overlapped workpieces at a joining point while rotating the tool at a high speed. Is pressed into the workpiece. Then, the work softened by the frictional heat with the joining pin is dragged by the rotation of the joining pin and the tool, and plastic flow occurs in the solid state. This is a method of integrating workpieces metallurgically using this.

  This friction stir welding method is very effective for joining the same kind of materials, and is widely used in various fields in the industry. However, if this joining method is used as it is for joining dissimilar metal materials, the physical properties such as friction stir temperature of the dissimilar metal materials are different, so even if plastic flow does not occur properly in both metal materials or plastic flow occurs. Usually, a brittle alloy part similar to the above is formed, and it is usually impossible to effectively join with sufficient joining strength.

  Therefore, a method of joining different metal materials by applying this friction stir welding technique to diffusion bonding has been developed. Here, the diffusion bonding method means that there is a large gap between the opposing surfaces of a pair of superimposed workpieces at the atomic level, but when pressurizing and heating the bonded portion of these workpieces, The microscopic irregularities of the opposing workpiece surfaces are eliminated, the surfaces are close to each other at the atomic level, and an atomic bond or interatomic attractive force is generated between both surfaces by a phenomenon called atomic diffusion. This is a method of joining a pair of workpieces by utilizing the connection between atoms.

  As the simplest joining method using this method, for example, as shown in FIG. 6, a rotating jig 100 whose tip is substantially spherical with respect to the workpieces W1 and W2 made of stacked different metal materials is used. Is pressed from above and pressed and heated while stirring the workpiece W2 at the joining portion, thereby bonding between the metal material atoms constituting the workpiece W2 and the metal material atoms constituting the workpiece W1. A method is known in which workpieces are joined together by diffusion bonding. At that time, if one point is pressed with the rotary jig 100, point joining is performed, and if the tool is moved while pressing, line joining is performed.

  As an improved joining method, a joining pin is inserted from the work side having a lower friction stirring temperature at a temperature lower than the melting temperature of an alloy or intermetallic compound made of a metal material constituting each of the stacked works W1 and W2. A method has been proposed in which workpieces having low frictional stirring temperatures are stirred to cause diffusion bonding to join the workpieces while preventing the formation of an alloy or intermetallic compound by pressing (see Patent Document 1).

Further, the metal material constituting each of the pair of workpieces W1 and W2 and the diffusible alloy material are interposed between the two workpieces, and the tip is pressed with a substantially flat rotary jig and stirred, and the alloy material Has been proposed (see Patent Document 2).
JP 2003-170280 A JP 2002-66759 A

  However, when viewed microscopically, since the surface of the workpiece is coated with an oxide generated by oxidation with oxygen in the air, the diffusion bonding method using the friction stir welding method is opposed to If the oxide film on the workpiece surface is destroyed in a wide range and the area of the portion where the metal atoms on the workpiece surface are directly connected to each other is not increased, a good bonding state cannot be obtained.

  In the joining method shown in FIG. 6 and the joining method described in Patent Document 1, only the oxide film in a narrow range near the tip portion of the rotating jig 100 and the tip portion of the thin joining pin that are substantially spherical is destroyed. There is a problem that the area of the part directly connected between atoms on the workpiece surface is reduced, and there is a case where the bonding strength is not always sufficiently obtained.

  In that respect, in the joining method described in Patent Document 2, the workpiece is pressed and heated by a substantially flat tip of a rotating jig that rotates at high speed, regardless of whether an alloy material is used or not. Since the oxide film on the workpiece surface is destroyed in a relatively wide area as much as the area of the tip of the rotary jig and the area where the bonds between atoms are increased, there is an advantage that the bonding strength is easily obtained.

  However, this method has a problem that the driving force to be applied to the rotating jig is increased because the work surface having a relatively large area must be pressed with a large pressure at the substantially flat tip of the rotating jig. Further, as shown in FIG. 7, a concave portion having a relatively large area is formed in the joint portion P of the workpiece after joining, and the workpiece W2 on the side pressed by the portion becomes thin, so that the joining strength at the joint portion P is reduced. As a result, there was a problem of weakening.

  Accordingly, an object of the present invention is to increase the fracture area of the oxide film on the surface of the opposing workpiece and obtain a high bonding strength in the bonding of dissimilar metal materials by the diffusion bonding method using the friction stir welding method. It is to provide a method for joining different metal materials. At the same time, an object of the present invention is to provide a method for joining dissimilar metal materials that can prevent a reduction in joining strength by preventing the thickness of the workpiece at the joining portion from becoming as thin as possible.

  In order to solve the above-described problem, the dissimilar metal material joining method according to claim 1 is characterized in that the second member made of a metal material different from the first member with respect to the first member made of a metal material and having a recess. The first member and the second member are pressed from the opening side of the concave portion of the first member and pressed against the inner surface of the concave portion of the first member while stirring the second member by rotation of a rotary jig. And are joined.

  According to the first aspect of the present invention, a rotary jig rotating at high speed is press-fitted into the second member overlapped with the first member, and a plastic flow is generated in the second member, which is stirred. By pressing the heated second member against the inner surface of the recess of the first member, the oxide film present at the interface between the first member and the second member is destroyed.

  According to a second aspect of the present invention, in the method for joining dissimilar metal materials according to the first aspect, the surface of the second member facing the first member is located at a position corresponding to the concave portion of the first member. A convex portion that can be fitted into the concave portion is formed.

  According to the second aspect of the present invention, the first member and the second member are overlapped and joined so that the convex portion formed on the second member is fitted into the concave portion formed on the first member.

  According to a third aspect of the present invention, in the method for joining dissimilar metal materials according to the first or second aspect, the concave portion of the first member has a bottomed circular hole shape or an inner peripheral surface of a tapered surface. It is formed in the shape of a round hole with a bottom.

  According to invention of Claim 3, the 2nd member heated by the recessed part of the 1st member formed in the bottomed circular hole shape or the bottomed circular hole shape by which the inner peripheral surface was made into the taper surface is provided. It is pressed and point joining is performed.

  According to a fourth aspect of the present invention, in the method for joining dissimilar metal materials according to the first or second aspect, the concave portion of the first member is formed in a groove shape.

  According to invention of Claim 4, the 2nd member heated by the recessed part of the 1st member formed in groove shape is pressed, and line joining is performed.

  According to a fifth aspect of the present invention, in the method for joining dissimilar metal materials according to any one of the first to fourth aspects, the second member is pressed and stirred by the rotation of the rotary jig. The concave portion of the first member is heated from the outside.

  According to the fifth aspect of the present invention, for example, in order to counter the pressing force of the rotary jig, the heating device is disposed at a position facing the concave portion of the support jig that supports the first member and the second member from the back side. It provides and joins, heating the recessed part of a 1st member from the outside.

  A sixth aspect of the present invention is the method for joining dissimilar metal materials according to any one of the first to fifth aspects, wherein the rotary jig is pressed against the second member by the rotation of the rotary jig. A plate-shaped shoulder portion that contacts the second member during agitation is formed.

  According to the sixth aspect of the present invention, for example, a disk-shaped shoulder portion is formed in the rotary jig, and at the time of joining, the shoulder portion contacts the second member from above or presses the second member. Joining is performed in the state.

  According to a seventh aspect of the present invention, in the method for joining dissimilar metal materials according to any one of the first to sixth aspects, the metal material of the second member is longer than the metal material of the first member. It is characterized by a low elastic modulus.

  According to the seventh aspect of the present invention, the first member having a concave portion having a high longitudinal elastic modulus and the second member having a low longitudinal elastic modulus are overlapped, and the rotary jig is press-fitted from the second member side to be joined. I do.

  The invention according to claim 8 is the method for joining dissimilar metal materials according to claim 7, wherein the metal material of the first member is iron or a metal material mainly composed of iron.

  According to invention of Claim 8, a 1st member is formed from the metal material which has iron or iron as a main component with high longitudinal elastic modulus.

  The invention according to claim 9 is the method for joining dissimilar metal materials according to claim 7 or claim 8, wherein the metal material of the second member is aluminum or a metal material mainly composed of aluminum. Features.

  According to the invention described in claim 9, the second member is formed of aluminum having a low longitudinal elastic modulus or a metal material mainly composed of aluminum.

  According to the first aspect of the present invention, a rotary jig rotating at high speed is press-fitted into the second member overlapped with the first member, and a plastic flow is generated in the second member, which is stirred. By pressing the heated second member against the inner surface of the recess of the first member, the oxide film present at the interface between the first member and the second member is destroyed over the entire inner surface of the recess of the first member.

  Therefore, in the joining method using the conventional rotating jig shown in FIG. 6, only the oxide film in a narrow range near the tip of the rotating jig is destroyed, whereas the bottom and side surfaces of the concave portion of the first member are A wide range of oxide film is destroyed. Since the metal atoms constituting the first member and the metal atoms constituting the second member are close to each other at the atomic level at these portions, the atoms are connected to each other due to the diffusion phenomenon of the atoms, thereby forming a diffusion junction. A sufficiently strong bonding strength can be obtained.

  Further, the depth and shape of the concave portion of the first member are determined in accordance with the thickness of the second member, etc., and the diameter and press-fitting distance of the rotary jig are selected and adjusted, so that the second member at the joint portion is adjusted. Since it is possible to prevent the thickness from becoming unnecessarily thin, it is possible to effectively prevent a decrease in the bonding strength at the bonded portion.

  According to the second aspect of the present invention, the first member and the second member are overlapped and joined so that the convex portion formed on the second member is fitted into the concave portion formed on the first member. In the case where the flat plate-like second member is pressed with the rotary jig and pressed against the concave portion of the first member, there is a possibility that the thickness of the second member becomes thin due to deformation. By providing the protrusions on the member, it is possible to sufficiently secure the thickness of the second member at the joint portion, and the effects of the invention described in the above claims can be exhibited more reliably.

  According to invention of Claim 3, the 2nd member heated by the recessed part of the 1st member formed in the bottomed circular hole shape or the bottomed circular hole shape by which the inner peripheral surface was made into the taper surface is provided. It is pressed and point bonded. For this reason, since the oxide film is uniformly and entirely destroyed at least on the inner peripheral surface of the circular hole-shaped concave portion of the first member by the plastic flow of the heated second member, the concave portion has other diameters and widths similar to each other. Compared with the case where it is formed in a shape, the oxide film can be destroyed in a wider range, and the effects described in the above claims can be exhibited more effectively.

  According to invention of Claim 4, the 2nd member heated by the recessed part of the 1st member formed in groove shape is pressed, and line joining is performed. Therefore, the movement of the rotary jig is guided to the groove-shaped concave portion, and the bonding can be reliably performed. At the same time, the oxide film is destroyed over the entire inner surface and bottom surface of the groove-shaped recess, and diffusion bonding is performed in a very wide range, so that the effects of the inventions described in the above claims can be effectively exhibited. .

  According to the fifth aspect of the present invention, in addition to heating by frictional heat between the second member and the rotating jig, the first member is joined by heating the concave portion of the first member from the outside with a heating device or the like. Since the concave portion is also heated from the outside, it becomes possible to improve the heating efficiency of the concave portion, and thereby, the destruction of the oxide film at the interface between the first member and the second member is more reliably performed, Since the phenomenon of atomic diffusion at the interface can be caused more accurately, the effects of the inventions described in the above claims can be more accurately exhibited.

  According to the invention described in claim 6, the pressure applied to the second member is increased by joining the shoulder portion of the rotary jig to the second member from above or pressing the second member. The oxide film at the interface between the first member and the second member can be destroyed more efficiently, and the effects of the inventions described in the above claims can be more effectively exhibited. Further, if the shoulder portion is provided, it is possible to effectively prevent the second member from being scattered due to the high-speed rotation of the rotary jig, and effectively prevent the thickness of the second member from being reduced at the joint portion. can do.

  According to the seventh aspect of the present invention, the first member having a concave portion having a high longitudinal elastic modulus and the second member having a low longitudinal elastic modulus are overlapped, and the rotary jig is press-fitted from the second member side to be joined. I do. Therefore, in addition to the effects of the inventions described in the above claims, the rotary jig can be easily press-fitted into the second member having a low longitudinal elastic modulus, and the first member can be used to deform the second member. It is possible to effectively prevent following deformation.

  According to invention of Claim 8, a 1st member is formed from the metal material which has iron or iron as a main component. According to the ninth aspect of the present invention, the second member is made of low aluminum or a metal material mainly composed of aluminum. As described above, in the manufacture of automobiles, railway vehicles, and the like, it is necessary to join a steel material and a non-ferrous light metal such as aluminum, but a recess is provided in the first member made of a steel material having a high longitudinal elastic modulus. In addition, by superposing nonferrous light metals such as aluminum with low longitudinal elastic modulus and pressing and stirring the rotating jig from the nonferrous light metal side, the effects of the inventions described in the above claims are effectively exhibited, It is possible to perform reliably.

  Embodiments of a method for joining dissimilar metal materials according to the present invention will be described below with reference to the drawings. In the joining method of dissimilar metal materials by the diffusion joining method using the friction stir welding method as in the present invention, the spot welding in which the rotary jig does not move with respect to the workpiece and spot welding is performed, and the rotary jig is a workpiece. There is a line bonding in which the bonding is performed while moving.

[First Embodiment]
First, in the present embodiment, a case where point bonding is performed using the bonding method of different metal materials according to the present invention will be described. In the present embodiment and a second embodiment to be described later, the workpieces W1 and W2 will be described as a first member 1 and a second member 2, respectively.

  The first member 1 is made of, for example, iron or a metal material containing iron as a main component. As shown in the cross-sectional view of FIG. 1, the joint P on the first member is previously bottomed with a press or the like. A circular hole-shaped recess 11 is formed. In the present embodiment, the inner diameter φ1 and the depth of the recess 11 are assumed to be about 1 to 10 mm, but these values are appropriately determined.

  The second member 2 is made of, for example, aluminum or a metal material containing aluminum as a main component, which is different from the metal material constituting the first member 1, and as shown in the sectional view of FIG. A convex portion 21 that can be fitted into the concave portion 11 of the first member 1 is formed on the surface of the two members 2 facing the first member 1, that is, the lower surface in the drawing. The convex portion 21 is provided in a position corresponding to the concave portion 11 of the first member 1 at the joining point P in advance by a press machine or the like.

  In the present embodiment, the outer diameter φ2 of the convex portion 21 is formed to be slightly smaller than the inner diameter φ1 of the concave portion 11 so that the first member 1 can be easily fitted into the concave portion 11. The outer diameter φ2 of the convex portion 21 and the inner diameter φ1 of the concave portion 11 are formed to be equal, or the outer diameter φ2 of the convex portion 21 is slightly larger than the inner diameter φ1 of the concave portion 11, and the convex portion 21 is press-fitted into the concave portion 11. It is also possible to do so. Moreover, the convex part 21 does not necessarily need to be provided in the second member 2.

  In joining, as shown in FIG. 2, the first member 1 and the second member 2 are overlapped so that the convex portion 21 of the second member 2 is fitted from the opening side of the concave portion 11 of the first member 1. A cylindrical rotary jig 3 whose tip is formed in a substantially hemispherical shape in the concave portion 22 inside the convex portion 21 of the second member 2 is rotated at a high speed around a rotation axis in the longitudinal direction by a rotational drive of a rotary pressing device (not shown). It is designed to be press-fitted in a state where When the convex part 21 is not provided in the 2nd member 2, the 2nd member 2 is piled up from the opening part side of the recessed part 11 of the 1st member 1, and the rotary jig 3 is rotated at a high speed by the pressing force. The two members 2 are pushed into the recesses 11 of the first member 1 to obtain the state shown in FIG.

  In the present embodiment, a wide disk-shaped shoulder 31 is integrally formed concentrically with the rotary jig 3 around the rotation axis of the rotary jig 3 at a position away from the tip on the rotary jig. The distance between the tip of the rotary jig 3 and the surface of the shoulder portion 31 facing the second member 2, that is, the lower surface in the drawing, is longer than the depth of the concave portion 22 of the second member 2, and the concave portion of the first member 1. The rotary jig 3 is press-fitted into the recess 22 of the second member 2, and its tip is pushed into the bottom of the recess 22, but at the bottom of the recess 11 of the first member 1. The shoulder portion 31 comes into contact with the second member 2 at a stage where it does not reach.

  The metal material constituting the second member 2 desirably has a lower longitudinal elastic modulus than the metal material constituting the first member 1. This is because when the longitudinal elastic modulus of the second member 2 is high, it becomes difficult to press-fit the rotary jig 3, and when the longitudinal elastic modulus of the first member 1 is low, the first member 1 follows the deformation of the second member 2. Based on the possibility of deformation. In particular, when the second member 2 is not provided with the convex portion 21 and is pushed into the concave portion 11 of the first member 1 by the pressing force of the rotary jig 3, the relationship between the longitudinal elastic moduli of both is as described above. It is preferable.

  Further, as shown in FIG. 3, the concave portion 11 of the first member 1 can be formed in a bottomed circular hole shape whose inner peripheral surface is a tapered surface. In that case, the convex part 21 of the 2nd member 2 is also formed in a taper shape according to the shape of the concave part 11. The reason for this is mainly to make it easy to press-fit the tip of the rotary jig 3, but even when formed in this way, the effects of the present invention can be effectively achieved.

  Furthermore, in the case of joining, in order to oppose the pressing force of the rotary jig 3, a support jig for supporting the first member 1 and the second member 2 from the back side is attached. As shown in FIG. 4, the support jig 4 is provided with a through hole or a recess for accommodating the recess 11 of the first member 1. In the present embodiment, a heating device 5 for heating from the outside so as to surround the recess 11 of the first member 1 is attached to an inner peripheral surface such as a through hole of the support jig 4.

  The heating device 5 is not particularly limited as long as it can heat the recess 11. In the present embodiment, a high-frequency heating device that can be attached to the inner peripheral surface with an inner diameter of about 10 mm and can efficiently heat the recess 11 is used. Yes. Moreover, it is more preferable if it is comprised so that the bottom face side of the recessed part 11 can also be heated.

  Next, the operation of the dissimilar metal material joining method according to the first embodiment will be described.

  When the rotary jig 3 that rotates at high speed is press-fitted into the second member 2 from above the first member 1 and the second member 2 that are superposed, the portion of the convex portion 21 of the second member 2 is subjected to frictional heat with the rotary jig 3. Is softened by heating, and a plastic flow is generated and stirred. At the same time, the convex portion 21 of the second member 2 is pressed against the inner peripheral surface and the bottom surface, that is, the inner surface of the concave portion 11 of the first member 1 by the pressing force from the rotary jig 3.

  Heating of the convex portion 21 of the second member 2 and the concave portion 11 of the first member 1 due to the high-speed rotation of the rotating jig 3, and plastic flow and stirring of the convex portion 21 of the second member 2 of the second member 2 The outer surface of the convex portion 21 of the second member 2 and the concave portion of the first member 1 due to the pressure applied from the second member 2 to the first member 1 due to the frictional action on the first member 1 and the pressing force of the rotary jig 3. 11, that is, the oxide film present on the opposing surfaces of both members is destroyed.

  And, over the entire inner surface of the concave portion 11 of the first member 1, diffusion bonding with the convex portion of the second member 2, that is, metal atoms constituting the first member 1 and metal atoms constituting the second member 2 are The first member 1 and the second member 2 are joined at the joint point P by being close to each other at the atomic level and generating an atomic bond or an interatomic attractive force.

  In addition, when the concave portion 11 of the first member 1 is formed in a bottomed circular hole shape whose inner peripheral surface is a tapered surface, bonding is performed on the same principle. When the shoulder 31 is formed on the rotary jig 3, the second member 2 is pressed from above or the concave portion 11 of the first member 1 when the second jig 2 is pressed and stirred by the rotary jig 3. The shoulder member 31 presses and prevents the metal material of the second member 2 trying to escape in the direction of the opening of the second member 2 from above, and the shoulder member 31 pressurizes the second member 2 plastically flowing from above. The pressure applied to the member 2 becomes larger.

  As described above, according to the joining method of dissimilar metal materials of the present embodiment, for example, the thin rotary jig 3 having a diameter of about 1 to several mm is used, which is the same as the conventional rotary jig 100 shown in FIG. However, the second member 2 is frictionally stirred not only at the tip but also at the side surface, and the second member is heated to a temperature higher than the friction stirring temperature not only at the bottom surface of the recess 11 of the first member 1 but also at the inner peripheral surface. 2 can be pressed to destroy the oxide film throughout the inner surface of the recess 11.

  Therefore, compared with the conventional joining method using the rotary jig 100, diffusion bonding can be generated over a wider range between the first member 1 and the second member 2, and a sufficiently high joining strength can be obtained. it can.

  Moreover, if the recessed part 11 of the 1st member 1 is heated from the outside by providing the heating apparatus 5 in the support jig 4 as mentioned above, the heating by the frictional heat of the 2nd member 2 and the rotary jig 3 will be carried out. In addition, since the recess 11 is also heated from the outside, the heating efficiency of the recess 11 can be improved. Thereby, the oxide film at the interface between the first member 1 and the second member 2 is more reliably destroyed, and the phenomenon of atomic diffusion at the interface can be caused more accurately.

  On the other hand, the inner diameter, depth, and shape of the recess 11 of the first member 1 are determined in accordance with the thickness of the second member 2 to be joined to the first member 1, and the diameter of the rotary jig 3, the press-fitting distance, etc. It is technically easy to select and adjust. Therefore, by appropriately selecting and determining them, the thickness of the convex portion of the second member 2 at the time of bonding can be prevented from becoming unnecessarily thin, and the bonding strength at the bonding point P decreases. This can be effectively prevented.

  In addition, as described above, the shoulder 31 is provided in the rotary jig 3, and the second member 2 that is plastically flowing at the time of joining can be pressurized from above, so that the pressure applied to the second member 2 increases. It is possible to effectively cause diffusion bonding by destroying the oxide film at the interface more efficiently. Further, if the shoulder portion 31 is not provided, the second member 2 in which plastic flow is generated may escape or scatter upward due to the high-speed rotation of the rotary jig 3, but the shoulder portion 31 may be such a second member. In order to effectively prevent the scattering of 2 and the like, it is possible to prevent the thickness of the second member 2 from being thinned at the joining point P and to effectively prevent a reduction in joining strength.

[Second Embodiment]
Next, in the second embodiment, a case will be described in which line bonding is performed using the bonding method of dissimilar metal materials according to the present invention.

  As in the first embodiment, the first member 1 is previously formed with a recess by a press or the like, but in this embodiment, as shown in FIG. A groove-like recess 12 is formed. In addition, although the recessed part 12 is expressed as a groove | channel where an opening part becomes narrow as it goes to a bottom face in the figure, it is not limited to this shape.

  In the present embodiment, on the surface side of the second member 2 facing the first member 1, a hook-shaped convex portion 23 that can be fitted into the groove-shaped concave portion 12 of the first member 1, that is, an elongated and linear shape. A convex portion 23 is formed. This convex part 21 is provided in the position corresponding to the recessed part 12 of the 1st member 1 of the junction part P previously with a press machine.

  In the joining, as shown in FIG. 5, the first member 1 and the second member 2 are overlapped so that the convex portion 23 of the second member 2 is fitted from the opening side of the concave portion 12 of the first member 1. The rotary jig 3 rotating at high speed is press-fitted into the concave portion 24 inside the convex portion 23 of the second member 2 and is moved along the concave portion 24.

  Here, the flat plate-like second member 2 on which the convex portion 21 is not provided can be overlapped with the first member 1 and joined, but as described above, the second member 2 has a bowl-like convex shape. If the portion 23 or the corresponding groove-like recess 24 is formed, the rotary jig 3 can be easily moved and reliably joined.

  The rotary jig 3 has a disk-shaped shoulder 31, and it is desirable that the metal material constituting the second member 2 has a lower longitudinal elastic modulus than the metal material constituting the first member 1. This is the same as in the first embodiment.

  Also in the present embodiment, a supporting jig for supporting the first member 1 and the second member 2 from the back side is attached at the time of joining. Although not shown in the drawings, as the support jig, for example, a pair of linear members arranged in a manner sandwiching the groove-like concave portion 12 of the first member 1 or a member having a concave cross section is used. A heating device is provided at a position facing the concave portion 12 of the support jig.

  The method for joining dissimilar metal materials according to the second embodiment is different from the first embodiment in that the rotary jig 3 is moved while rotating at a high speed, but the operation is the same as in the case of the first embodiment. This is exactly the same and will not be described.

  As described above, also in the joining method of dissimilar metal materials according to the present embodiment, the second member 2 is frictionally stirred at the tip and side surfaces of the rotary jig 3 to the bottom surface and the inner peripheral surface of the recess 12 of the first member 1. Then, the second member 2 can be pressed and the oxide film can be broken across the entire inner surface of the recess 12. Therefore, compared with the conventional joining method using the rotary jig 100, diffusion bonding can be generated over a wider range between the first member 1 and the second member 2, and a sufficiently high joining strength can be obtained. it can.

  Moreover, the heating efficiency of the recessed part 12 can be improved by heating the recessed part 12 of the 1st member 1 from the outside by providing a heating apparatus in a support jig, and, thereby, the 1st member 1 is improved. The oxide film at the interface between the first member 2 and the second member 2 can be more reliably destroyed, and the phenomenon of atomic diffusion at the interface can be caused more accurately.

  Further, the width, depth, and shape of the recess 12 of the first member 1 are determined in accordance with the thickness of the second member 2 to be joined to the first member 1, and the diameter, press-fit distance, etc. of the rotary jig 3 are determined. By selecting and adjusting, the thickness of the convex portion of the second member 2 at the time of joining can be prevented from becoming unnecessarily thin. Therefore, it is possible to effectively prevent the bonding strength at the bonding portion P from being lowered.

  In addition, by providing the shoulder 31 in the rotary jig 3, it is possible to pressurize the second member 2 that is plastically flowing at the time of joining from above, so that the pressure applied to the second member 2 increases, It is possible to effectively cause diffusion bonding by destroying the oxide film more efficiently. Further, since the shoulder portion 31 effectively prevents the second member 2 from being scattered, the thickness of the joint portion P of the second member 2 is prevented from being reduced, thereby effectively preventing a decrease in joint strength. It becomes possible.

  The press-fitting time of the rotary jig 3 in the first embodiment, the moving speed of the rotary jig 3 in the second embodiment, the rotational speed of the rotary jig 3 in both embodiments, and the like are the same as those of the first member 1 and the first member. It is appropriately set so that the oxide film at the interface of the two members 2 can be effectively destroyed.

  In the first and second embodiments, the cylindrical rotary jig 3 whose tip is formed in a substantially hemispherical shape has been described. However, the cylindrical jig is limited to this shape as long as the effect of the present invention is effectively exhibited. Instead, for example, a polygonal prism shape can be used instead of a cylindrical shape, or a spiral protrusion or the like can be formed on the outer peripheral surface of the rotary jig 3.

It is sectional drawing which shows the structure of the 1st member used for the joining method of the dissimilar metal material which concerns on 1st Embodiment, and a 2nd member. It is a partial cross section figure which shows the state which press-fitted the rotation jig to the 1st, 2nd member. It is sectional drawing which shows the modification of a 1st member. It is a partial cross section figure which shows the attachment position of a support jig and a heating apparatus. It is a perspective view which shows the state which press-fitted the rotation jig in the 1st, 2nd member in 2nd Embodiment. It is a fragmentary sectional view explaining the joining method of the conventional different metal material. It is sectional drawing which shows the workpiece | work after joining in the conventional joining method using the rotary jig which has a substantially flat-shaped front-end | tip.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st member 11, 12 Concave part 2 2nd member 21, 23 Convex part 3 Rotating jig 31 Shoulder part

Claims (9)

  A first member made of a metal material and having a concave portion is overlapped with a second member made of a metal material different from the first member from the opening side of the concave portion of the first member, and the rotation jig rotates to rotate the second member. A method of joining different metal materials, wherein the second member is pressed against the inner surface of the concave portion of the first member while stirring the second member to join the first member and the second member.   The convex part which can be engage | inserted in the said recessed part is formed in the position corresponding to the said recessed part of the said 1st member in the surface facing the said 1st member of the said 2nd member. Of joining different metal materials.   The concave portion of the first member is formed in a bottomed circular hole shape or a bottomed circular hole shape whose inner peripheral surface is a tapered surface. A method for joining dissimilar metal materials.   The method for joining different metal materials according to claim 1, wherein the concave portion of the first member is formed in a groove shape.   The dissimilar metal according to any one of claims 1 to 4, wherein the concave portion of the first member is heated from the outside when the second member is pressed and stirred by rotation of the rotary jig. Material joining method.   The plate-shaped shoulder part which contact | abuts to the said 2nd member at the time of the press of the said 2nd member by rotation of the said rotation jig, and stirring is formed in the said rotation jig. Item 6. The method for joining dissimilar metal materials according to any one of Items 5 to 6.   The method for joining different metal materials according to any one of claims 1 to 6, wherein the metal material of the second member has a lower longitudinal elastic modulus than the metal material of the first member.   The method for joining different metal materials according to claim 7, wherein the metal material of the first member is iron or a metal material containing iron as a main component.   9. The method for joining different metal materials according to claim 7, wherein the metal material of the second member is aluminum or a metal material mainly composed of aluminum.

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