JP2002079383A - Method of joining and joining tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of joining by which a sound joined part having no defect or near the surface of metal is surely available when metallic members whose melting points are different from each other are joined with a friction stir welding, and a joining tool used for the method. SOLUTION: The method for joining includes a process where an aluminum alloy member 1 and an oxygen-free copper 2 which have different melting points are lapped, a process where a joining tool 10, which has a cylindrical main body 11 and a projected probe 12 on the bottom face 11a of the main body, is located near the surface of the aluminum alloy member 1 whose melting point is lower, and a backing member 6, whose thermal conductivity is lower than that of the oxygen-free copper 2, is located near the back face of the oxygen-free copper 2 whose melting point is higher, and on the opposite side from the joining tool 10, and a process where a friction stir welding of the aluminum alloy member 1 and the oxygen-free copper 2 is performed along their lapped part 4 by making the joining tool 10 enter the vicinity of the lapped part 4 of the aluminum alloy member 1 and the oxygen-free copper 2 while rotating the tool 10, and moving the tool in the longitudinal direction of the lapped part 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joining method for performing friction stir welding in a state where two metal members having different melting points are superimposed on each other, and a joining tool used therefor.
In this specification, aluminum includes an aluminum alloy.

[0002]

2. Description of the Related Art In joining two metal members having different melting points, for example, an aluminum member and a copper member, TIG or MIG is required.
When a direct melting method such as IG welding is used, an intermetallic compound is easily generated at the joint. To avoid this, a method such as friction welding, explosive welding, or brazing is used for the joining. However, when friction welding is used to join the aluminum member and the copper member, the cross-sectional shape of the member to be joined is limited to a bar or a tube. Also, when explosive pressure welding is used, the cross-sectional shape of the members to be joined is limited and the cost is increased. Furthermore, when brazing is used, there is a problem that the quality of the joint at the joint is not stable, and the joint product obtained when heated to a high temperature is easily deformed.

[0003] In order to solve the above problems and to join an aluminum member and another metal member having different melting points to each other, it has been proposed to use friction stir welding. For example, when a high-speed rotating probe is brought into contact with a joined portion where an aluminum member and a dissimilar metal member are superimposed and softened by frictional heat to perform friction stir welding, a probe is used from the stronger member side of the two members. There has been proposed a joining method of bringing the two into contact with each other (see Japanese Patent Application Laid-Open No. Hei 10-137952). However, in this joining method, it is difficult to insert the probe into the vicinity of the overlapping portion, and the life of the joining tool including the probe is shortened, so that there is a problem that the process management is complicated and the cost is increased.

Further, as shown in FIG. 6A, a center of a bottom surface 37 of a rotating cylindrical rotor 36 of a joining tool 34 is provided near an overlapping portion 33 where an aluminum member 31 and a copper member 32 are overlapped. A joining method has been proposed in which a probe 38 is inserted from the soft aluminum member 31 side when a probe 38 is inserted from the soft aluminum member 31 when the two members 31 and 32 are joined by softening and agitating by frictional heat and stirring. (See Japanese Patent Application Laid-Open No. 10-328855). According to this joining method, the soft aluminum member 3
Since the plasticization of 1 is easy, the insertion of the probe 38 is also easy, and the agitation between the metals of the two members 31 and 32 can be smoothly performed. Therefore, no defect is generated in the vicinity of the overlapping portion 33 and the joining strength is improved. Has advantages.

[0005] However, depending on the selection of the welding tool 34 including the probe 38 and the welding conditions, a defect may occur in the welded portion. That is, as shown in FIG.
The heat input to the members 31 and 32 is
And friction with the bottom surface (shoulder) 37, but most of the friction is due to the friction with the bottom surface 37. Therefore, the amount of heat input in the vicinity of the overlapping section 33 increases near the bottom surface 37,
It decreases on the tip side of the probe 38. For this reason, when the probe 38 is inserted from the soft aluminum member 31 side, the hard copper member 3 located near the tip of the probe 38
The amount of heat input to 2 is reduced. As a result, as shown in FIG. 6B, insufficient flow of the copper material occurs in the copper member 32, so that an internal defect (cavity) K1 occurs at a position near the tip of the probe 38 at the joint W. There is.
On the other hand, if the number of rotations of the probe 38 and the rotor 36 is increased to increase the amount of heat input at a position near the tip of the probe 38, the amount of heat input to the aluminum member 31 further increases and the flow resistance of the aluminum member 31 decreases. It decreases significantly. As a result, as shown in FIG. 6C, there is a problem that a part of the aluminum member 31 leaks to the outside from the vicinity of the bottom surface 37, thereby causing a surface defect K2.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems in the prior art and, when friction stir welding is performed on metal members having different melting points from each other, a sound member having no defect inside or near the surface. An object of the present invention is to provide a joining method capable of reliably obtaining a joining portion and a joining tool used for the joining method.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is conceived to prevent a temperature drop near a probe tip in a joining tool and to increase a heat input near a probe tip. It was made. That is, the first joining method of the present invention includes a step of superposing a pair of metal members having different melting points from each other, and forming a cylindrical main body near the surface of the low melting point side metal member of the pair of metal members. Arranging a joining tool having a probe protruding from the bottom surface, and arranging a backing material near a back surface of the metal member on the high melting point side facing the joining tool; and rotating the joining tool while rotating the joining tool. A step of moving the pair of metal members along the overlapping portion by friction stir welding by moving the metal member into the vicinity of the overlapping portion of the metal member and moving along the longitudinal direction of the overlapping portion. And

According to this, it is possible to prevent the frictional heat of the metal member on the high melting point contacting only near the tip of the probe having a diameter smaller than that of the main body of the joining tool from escaping to the back side, and to prevent the metal member on the high melting point from being removed. It is possible to suppress a temperature drop in the flowing / stirring portion. For this reason, the insufficient flow in the metal member on the high melting point side is eliminated. Therefore, in the vicinity of the overlapping portion between the two metal members having low and high melting points, the metals of both members are stirred while plastically flowing with each other, so that friction stir welding that forms a sound joint without internal defects and surface defects is performed. It can be carried out.

The friction stir welding is a method in which two metal members are softened and joined in a solid state, so that an intermetallic compound is not generated at the joint and a thermal influence is generated near the joint. There are no parts. Therefore, the reason why the two metal members are set to the low melting point side and the high melting point side as described above is to focus on the fact that the softening point (softening temperature range) has a similar relationship according to the respective melting points. Therefore, the low melting point side and the high melting point side can be expressed as a soft side and a hard side at the same heating temperature, a low strength side and a high strength side, or a high hardness side and a low hardness side. In addition, a tool formed from a hard metal or alloy having a higher melting point than the two metal members is used as the joining tool. Further, the backing material is made of a material having a lower thermal conductivity than the metal member on the high melting point side, and a ceramic or metal material having heat resistance is used.

[0010] In addition, a bonding method is also included in which the backing material has a lower thermal conductivity than the metal member on the high melting point side or has a heating means. According to this, it is possible to prevent a situation in which frictional heat in the metal member on the high melting point side that generates heat by friction with the vicinity of the tip of the probe is released from the back surface side of the metal member, and the temperature of the metal member on the high melting point side is reduced. Suppress. Alternatively, by preventing the above-described heat radiation and actively heating from the back surface side, it is possible to prevent a temperature drop near the overlapping portion of the metal member on the high melting point side. Note that a heat-resistant and low-thermal-conductivity material such as a ceramic material is used for the backing material, and a heater wire or the like is used for the heating means.

A second joining method according to the present invention is a joining method using a joining tool having a cylindrical main body and a probe on the bottom surface thereof and having an uneven portion at the tip of the probe. A step of superposing a pair of different metal members, a step of arranging the joining tool near the surface of the metal member on the low melting point side of the pair of metal members, and a step of rotating the joining tool. And a step of moving the pair of metal members along the overlapping portion by friction stir welding by entering the vicinity of the overlapping portion and moving along the longitudinal direction of the overlapping portion.

[0012] According to this, the frictional heat of the metal member on the high melting point side which comes into contact with only the vicinity of the probe tip of the welding tool increases in accordance with the increase of the contact area due to the uneven portion at the probe tip. For this reason, the lack of flow in the metal member on the high melting point side is eliminated, so that there is no internal defect near the overlapped portion of both metal members and there is no sound defect on the surface of the metal member on the low melting point side. Can be obtained. In addition, the above-mentioned uneven portion has a form in which a large number of protrusions are protruded in a lattice shape on the distal end face of the probe, a form in which one or more convex ridges are protruded on the distal end face, or a plurality of ring convexes concentrically on the distal end face. Includes forms with provisions. Also, a form in which a number of concave grooves or dents are protruded from the peripheral surface near the distal end surface of the probe along the axial direction thereof is included. Furthermore, together with a joining tool including a probe having the above uneven portion,
If friction stir welding is performed while using the backing material (including the heating means), more effective welding can be achieved.

A third joining method according to the present invention comprises at least a first portion including an outer peripheral portion of a cylindrical main body and a second portion including at least a probe tip, and the first portion and the second portion are separated from each other. A joining method using a joining tool that rotates coaxially and individually, wherein a step of superposing a pair of metal members having different melting points from each other, and a step near the surface of the metal member on the low melting point side of the pair of metal members. Arranging the joining tool, and causing the joining tool to enter the vicinity of the overlapping portion of the pair of metal members while rotating the second tool at a rotation speed higher than the rotation speed of the first portion; And moving the pair of metal members along the overlapped portion by friction stir welding by moving the overlapped portion along the longitudinal direction of the overlapped portion.

In a more specific third joining method, the first portion includes a cylindrical main body and a probe base end protruding from the bottom surface thereof, and the second portion includes a probe tip end. A joining method that includes a joining tool including first and second portions that are coaxial with each other and that are individually rotated, including a step of superposing a pair of metal members having different melting points from each other; Of which, a step of disposing the joining tool near the surface of the metal member on the low melting point side,
The joining tool is caused to enter the vicinity of the overlapping portion of the pair of metal members with a rotation in which the rotation speed of the second portion on the probe tip side is higher than the rotation speed of the first portion on the main body side, and the overlapping portion And moving the pair of metal members along the overlapping portion by friction stir welding by moving the pair of metal members along the longitudinal direction.

According to these, the second in the joining tool
Since the rotation speed of the portion is large, insufficient flow of the metal member on the high melting point side in contact with the probe or the vicinity of the tip of the portion is eliminated. For this reason, it is possible to approach or make similar to the heat value of the metal member on the low temperature side with which the first portion contacts. Therefore, it is possible to reliably form a sound joint having no internal defect or surface defect over the overlapped portion of the two metal members.

Further, one joining tool used in the third joining method includes a cylindrical main body or a first portion including an outer peripheral portion of the main body, a rotating shaft which coaxially penetrates the center of the main body, and a rotating shaft. A second portion including a probe located at a tip of a rotating shaft and protruding from a bottom surface of the main body, and a bearing disposed between the first portion and the second portion are provided. In addition, another joining tool used in the third joining method includes a first portion including a cylindrical main body and a probe base end protruding from the bottom surface thereof, a probe distal end portion, and a main body of the first portion. And a second portion including a rotating shaft penetrating the axis of the probe base end portion, and a bearing disposed between the first portion and the second portion. According to these, the second portion including the probe or the probe tip of the joining tool can be rotated at a higher speed than the first portion on the main body side or the first portion including the main body and the probe base end. For this reason, the insufficient flow of the metal member on the high melting point side is easily eliminated by the second portion.
Therefore, it is possible to reliably form a sound joint having no internal defect and no surface defect over the overlapped portion of the two metal members.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments and embodiments of the present invention will be described below with reference to the drawings. FIG. 1 relates to a first joining method of the present invention.
As shown in (A) and (a), an aluminum alloy material (low melting point side metal member) 1 and an oxygen-free copper (high melting point side metal member) 2 are overlapped and restrained, and Form. In the vicinity of the surface of the aluminum alloy material 1, a joining tool 10 including a cylindrical main body 11 made of, for example, high-speed steel and a probe 12 projecting coaxially from the center of a bottom surface 11a thereof.
Is arranged. As shown in FIG.
The axes of the main body 11 and the probe 12 are arranged at an angle of about 5 ° with respect to a perpendicular to the surface of the aluminum alloy material 1. Such a joining tool 10 is 500 to 15000r.
pm, and along its axis 1 to 3
It is inserted toward the overlapping portion 4 while applying a pushing force of 0 kN, and is sent to the right side in FIG. 1A at a moving speed of 50 mm to 2 meters / minute.

As shown in FIGS. 1A and 1A, oxygen-free copper 2
A backing material 6 having a rectangular cross section is disposed along the overlapped portion 4 near the back surface facing the joining tool 10 in FIG. The backing material 6 is made of steel or ceramic having a lower thermal conductivity than the oxygen-free copper 2. As shown in FIGS. 1 (B) and 1 (b), a rotating joining tool 10 is inserted from the aluminum alloy material 1 side, and the probe 12 is passed through the overlapping portion 4 and enters the oxygen-free copper 2. As shown by a straight arrow in FIG. 1B, it is moved rightward along the overlapping portion 4. During this time, the aluminum alloy material 1 comes into contact with the bottom surface 11a of the main body 11 of the welding tool 10 and the vicinity of the base end of the probe 12, and generates heat due to friction and is plasticized and fluidized. Further, the oxygen-free copper 2 comes into contact with the vicinity of the tip of the probe 12 of the welding tool 10 and generates heat due to friction and becomes plastic and fluid.

Then, the aluminum alloy material 1 and the oxygen-free copper 2 are agitated with each other, and a joining portion W is formed in which both metals are solidified in a mixed state as the joining tool 10 is separated. At this time, the backing material 6 suppresses the temperature drop of the oxygen-free copper 2 in the vicinity of the tip of the probe 12 of the bonding tool 10 in order to prevent the heat generated in the oxygen-free copper 2 from being radiated from the back side. I do. As a result, the difference in calorific value between the aluminum alloy material 1 and the oxygen-free copper 2 in the vicinity of the overlapping portion 4 is reduced, and insufficient flow of the oxygen-free copper 2 is eliminated, so that sound bonding without internal defects (cavities) is achieved. A part W can be obtained. Accordingly, with the movement of the joining tool 10, a sound joining portion W is formed along the overlapping portion 4, and various joining products (for example, various joining products in which the aluminum alloy material 1 and the oxygen-free copper 2 are strongly overlapped and joined together (for example, And a conductive joined body for a transformer terminal).

[0020]

Embodiments 1 and 2 Here, specific embodiments of the first joining method will be described together with comparative examples. Three sets of an aluminum alloy material 1 made of JIS: A6063 and having a length of 200 mm × a width of 100 mm × a thickness of 5 mm and an oxygen-free copper 2 having the same size were prepared. Further, a joining tool 10 prepared from a high-speed steel and including a main body 11 having a diameter of 20 mm and a probe 12 having a diameter of 9 mm and a length of 6 mm was prepared. As shown in FIGS. 1 (A) and 1 (a), each set of the aluminum alloy material 1 and the oxygen-free copper 2 are overlapped to form a superposed portion 4 for each set. Made of three types of materials on the back side of
A backing material 6 having a common size of 0 mm x width 100 mm x thickness 10 mm was arranged for each group. Among them, the material of the backing material 6 is made of a ceramic mainly composed of silicic acid in Example 1, and the material made of a steel material of ordinary steel in Example 2,
One made of oxygen-free copper was used as Comparative Example 1.

As shown in FIGS. 1 (B) and 1 (b), the joining tool 10 inclined from the surface side of the aluminum alloy material 1 of each example by 5 ° in the direction opposite to the moving direction is rotated at 700 rpm.
m, pushing pressure 12.5kN, moving speed 200mm /
, And moved along the polymerization section 4.
In each example, the heat generation temperature at the time of joining in the oxygen-free copper 2 was measured with a thermocouple, and the obtained joint W of each example was obtained.
Was cut, and the exposed cross section was visually inspected for defects. The results are shown in Table 1.

[0022]

[Table 1]

According to the results shown in Table 1, the exothermic temperatures of the oxygen-free copper 2 were 450 ° C. in Example 1 and 420 ° C. in Example 2.
On the other hand, in Comparative Example 1, the temperature was only 330 ° C., which was opposite to the high thermal conductivity of the backing material 6 in each example. According to the temperature, the joint W of Example 1 has no internal defect,
In Example 2, only small internal defects were found, whereas in Comparative Example 1, coarse internal defects of about 0.2 mm were found.
According to this result, in Examples 1 and 2, the first bonding method was used and the backing material 6 was made of a material having a lower thermal conductivity than the oxygen-free copper 2 on the high melting point side. It was found that the temperature drop near the tip was prevented, and no internal defects were generated or they were kept fine. The advantages of the first bonding method can be understood from the first and second embodiments.

FIG. 2 shows an application of the first joining method. As shown in FIGS. 2A and 2A, an aluminum alloy material is used.
The overlapping portion 4 is formed by overlapping and restraining the (low melting point side metal member) 1 and the oxygen-free copper (high melting point side metal member) 2. In the vicinity of the surface of the aluminum alloy material 1, the same main body 11 and probe 1
The joining tool 10 including the two is inclined and arranged like the above. As shown in FIGS. 2A and 2A, a backing material 8 having a rectangular cross section is disposed along the overlapping portion 4 near the back surface of the oxygen-free copper 2 facing the joining tool 10. This backing material 8
Also made of steel or ceramic having a lower thermal conductivity than oxygen-free copper 2, and a plurality of heater wires (heating means) inside thereof.
9 are built-in. As shown in FIGS. 2 (B) and 2 (b), the rotating welding tool 10 is inserted from the side of the aluminum alloy material 1 in a state where the heater wire 9 is energized in advance and the backing material 8 is heated. Is passed through the overlapping portion 4 to enter the oxygen-free copper 2 and is moved to the right along the overlapping portion 4 as shown by a straight arrow in FIG. 2B.

During the above, the aluminum alloy material 1 is brought into contact with the bottom surface 11a of the main body 11 of the welding tool 10 and the base end of the probe 12 to generate frictional heat and to be plasticized and fluidized. Also, the probe 1 of the joining tool 10
It comes into contact with the vicinity of the tip of No. 2 and generates heat due to friction and becomes plastic and fluid. As a result, the aluminum alloy material 1 and the oxygen-free copper 2
The two metal materials are mixed and solidified in a mixed state as the joining tool 10 is separated, and a joint W is formed. At this time, the backing material 8 prevents the frictional heat in the oxygen-free copper 2 from being radiated from the back side, and further heats the oxygen-free copper 2 by the built-in heater wires 9. For this reason, the temperature drop of the oxygen-free copper 2 in the vicinity of the tip of the probe 12 of the joining tool 10 is more reliably suppressed. As a result, the lack of flow of the oxygen-free copper 2 is eliminated, and a sound joint W without internal defects (cavities) can be obtained. Accordingly, a sound joining portion W is formed along the overlapping portion 4 with the movement of the joining tool 10, and a joined product in which the aluminum alloy member 1 and the oxygen-free copper 2 are strongly overlapped and joined can be obtained. .

[0026]

Embodiments 3 to 6 Here, specific embodiments of application forms of the first joining method will be described together with comparative examples. JIS: Made of A6063, length 200mm x width 100
Five sets of oxygen-free copper 2 having the same size as an aluminum alloy material 1 having a size of 5 mm × 5 mm were prepared. Further, a joining tool 10 prepared from a high-speed steel and including a main body 11 having a diameter of 20 mm and a probe 12 having a diameter of 9 mm and a length of 6 mm was prepared. As shown in FIGS. 2 (A) and 2 (a), each set of the aluminum alloy material 1 and the oxygen-free copper 2 are overlapped to form a superposed portion 4 for each set. Made of the same oxygen-free copper on the back side of the product, length 200 mm x width 100 mm x thickness 1
A backing material 8 having a common size of 0 mm was arranged for each set. The backing material 8 of each set includes a heater wire 9 having the same wiring. Then, the heater wire 9 is energized and the backing material 8
Surface temperature of 100 ° C, 200 ° C, 400 ° C, 500 ° C
Each of the sets individually heated was used in Examples 3, 4, 5, and 6, respectively.
A set in which the heater wire 9 was not energized was designated as Comparative Example 2.

As shown in FIGS. 2 (B) and 2 (b), the joining tool 10 inclined from the surface side of the aluminum alloy material 1 of each example by 5 ° in the direction opposite to the moving direction is rotated at 700 rpm.
m, pushing pressure 12.5kN, moving speed 200mm /
, And moved along the polymerization section 4.
In each example, the heat generation temperature at the time of joining in the oxygen-free copper 2 was measured with a thermocouple, and the obtained joint W of each example was obtained.
Was cut, and the exposed cross section was visually observed to check for defects. Table 2 shows the results.

[0028]

[Table 2]

According to the results shown in Table 2, in Examples 3 to 6, the temperature of the oxygen-free copper 2 was increased almost in proportion to the temperature of the backing material 8 and the temperature of the oxygen-free copper 2 was 420 ° C. Examples 4 and 47
In Example 5 at 0 ° C., no internal defect occurred in the joint W. Further, in Example 3 in which the temperature of oxygen-free copper 2 was slightly lower at 350 ° C., only minute internal defects were found, and in Example 6 in which the temperature of oxygen-free copper 2 was slightly higher at 520 ° C. A concave surface defect was observed. From these results, in Example 3, due to insufficient heating, the temperature of the oxygen-free copper 2 near the tip of the probe 12 could not be sufficiently prevented from lowering, and the flow was slightly insufficient. In Example 6, internal defects could be prevented by overheating. However, it is presumed that the flow resistance on the surface of the joint W was slightly reduced, resulting in minute surface defects.
On the other hand, in Comparative Example 2 in which the backing material 8 was not heated, about 0.
A coarse internal defect (cavity) of 2 mm was found. That is, in Comparative Example 2, it is estimated that coarse internal defects occurred due to insufficient flow in the oxygen-free copper 2 as in Comparative Example 1. The advantages of the first joining method can be understood from the above Examples 3 to 6.

FIG. 3 relates to the second joining method.
As shown in FIGS. 1A and 1B, a joining tool 10 used in this method includes a cylindrical main body 11 made of high-speed steel and a probe 12 protruding from the center of a bottom surface 11a thereof. A pair of ridges (irregular portions) 14 having a pair of cross shapes extending in the radial direction are protruded from the distal end surface (distal end portion) 12a. As shown in FIGS. 1A and 1A, an aluminum alloy material
(Low melting point side metal member) 1 and oxygen-free copper (high melting point side metal member) 2 are overlapped and restrained to form a superposed portion 4.
In the vicinity of the surface of the aluminum alloy material 1, a main body 11 is provided.
And a pair of ridges 14, 1 including the probe 12 and
The joining tool 10 having the above-mentioned 4 is arranged in an inclined manner as described above. However, the backing material 6 is not used. Then
As shown in FIGS. 1 (B) and 1 (b), a rotating joining tool 10 is inserted from the aluminum alloy material 1 side, and the tip surface 12a of the probe 12 is passed through the overlapping portion 4 so that the oxygen-free copper 2 While moving inward, it is moved rightward along the overlapping portion 4 as shown by a straight arrow in FIG.

During the above, the aluminum alloy material 1 is brought into contact with the bottom surface 11a of the main body 11 of the joining tool 10 and the vicinity of the base end of the probe 12 to generate heat by friction and to be plasticized and fluidized. 2 is also plasticized and fluidized by contacting the tip of the probe 12 of the welding tool 10 and the pair of ridges 14 and 14 to generate frictional heat. As a result, the aluminum alloy material 1 and the oxygen-free copper 2 are agitated with each other, and a joining portion W is formed in which both metals are solidified in a mixed state as the joining tool 10 is separated. At this time, the oxygen-free copper 2 also comes into frictional contact with the ridge 14 of the probe 12, and the amount of heat generated increases in accordance with the increase in the contact area, so that insufficient flow can be eliminated. As a result, internal defects (cavities)
A sound joining portion W without any gap can be formed along the overlapping portion 4.

As shown in FIGS. 3C and 3C, a small cubic projection (uneven portion) is formed on the distal end surface 12a of the probe 12.
As shown in FIGS. 3 (D) and 3 (d), a ring ridge is formed on the distal end surface 12a of the probe 12. As shown in FIGS.
(Concavo-convex portions) Even when the concentric projections 17, 18, and 19 are provided, the same operation and effect as the pair of ridges 14 can be obtained. Further, as shown in FIGS. 3 (E), 3 (e) and 3 (F), a concave groove (concavo-convex portion) along the axial direction is formed on a peripheral surface (tip portion) of the probe 12 of the joining tool 10 near the distal end surface 12a. ) 13 may be formed in the form of the ridges 14.
The same operation and effect as described above can be obtained. In addition, a large number of dents may be formed in the form of scattered spots in place of the above-mentioned concave groove 13, or the convex groove 14, the protrusion 16, or the ring convex may be formed on the distal end surface 12 a together with the concave groove 13 or the concave on the probe 12 peripheral surface. Article 1
It is also possible to add 7, 18, 19 and the like.

[0033]

Embodiments 7 to 9 Here, specific embodiments of the second joining method will be described together with comparative examples. JIS: Made of A6063, length 200mm x width 100
Four sets of an aluminum alloy material 1 having a size of 5 mm and a thickness of 5 mm and oxygen-free copper 2 having the same size were prepared. In addition, four sets of joining tools 10 prepared from a high-speed steel and including a main body 11 having a diameter of 20 mm and a probe 12 having a diameter of 9 mm and a length of 6 mm were prepared. Of these, the protrusion 1 having a side of 1 mm and a height of 1 mm shown in FIGS.
Example 6 is shown in FIG.
Example 8 shows a tool 10 shown in (B) in which a ridge 14 having a width of 2 mm and a height of 1 mm is projected in a cross shape. Further, FIG.
As shown in (D) and (d), the width and height are each 1 mm.
In, the diameter at the center in the radial direction (thickness direction) is 2 mm,
Example 9 was a tool 10 in which 5 mm and 8 mm ring ridges 17, 18, and 19 were protruded. On the other hand, the joining tool 10 having the probe 12 having only the flat tip surface 12a was used as Comparative Example 3.

As shown in FIGS. 1A and 1A, four sets of the aluminum alloy material 1 and the oxygen-free copper 2 are overlapped and constrained to form a polymerized portion 4 for each set. The joining tools 10 of each example were individually arranged in the same manner as described above. The joining tool 10 of each example, which was inclined by 5 ° from the surface side of each set of the aluminum alloy material 1 to the opposite side to the moving direction, was rotated at 700 rpm, a pushing pressure of 12.5 kN, and a moving speed of 200 mm /
1B, and were moved along the overlapping portion 4 as shown in FIGS. 1B and 1B. Using the joining tool 10 of Examples 7 to 9 or Comparative Example 3, the obtained joints W of Examples 7 to 9 and Comparative Example 3 were respectively cut, and the exposed cross section was visually observed to check for defects. Was examined. Table 3 shows the results.

[0035]

[Table 3]

According to the results shown in Table 3, in Examples 7 to 9,
While no internal defect occurred in each joint W, a coarse internal defect (cavity) of about 0.2 mm was found in the joint W of Comparative Example 3. That is, in Examples 7 to 9,
While the oxygen-free copper 2 was sufficiently fluidized by the concave and convex portions such as the ridges 14 and the like, Comparative Example 3 suffered from insufficient flow in the oxygen-free copper 2 as in Comparative Examples 1 and 2, It is presumed that coarse internal defects occurred. Example 7 above
According to Nos. To 9, the superiority of the second joining method is easily understood.

FIG. 4 relates to a third joining method and a joining tool 20 used for the third joining method. As shown in FIGS. 4 (A) and 4 (B), a welding tool 20 according to claim 7 is made of, for example, high-speed steel and has a cylindrical main body 21 and a probe protruding from the center of the bottom surface 21a. First part 2 including base end 22
0a and a probe distal end 24 coaxial with the proximal end 22.
And the axial hole 23 of the main body 21 and the probe base end 22.
And a plurality of bearings 28 disposed between the first portion 20a and the second portion 20b. First part 20a and second part 20
b is individually connected to a dedicated drive source such as a motor. Note that a heat-resistant sealing material 29 is disposed near the outer end between the first and second portions 20a and 20b.

As shown in FIGS. 4C and 4D, an aluminum alloy material (low melting point metal member) 1 and an oxygen-free copper (high melting point metal member) 2 are overlapped and restrained. A polymerization section 4 is formed. In addition, near the surface of the aluminum alloy material 1,
The joining tool 20 is disposed obliquely as described above. At this time, while the second portion 20b is being rotated at a higher rotation speed than the first portion 20a,
While applying a pushing force of N and inserting it toward the vicinity of the overlapping portion 4, the joining tool 20 is moved rightward in FIG. 4D at a moving speed of 50 mm to 2 meters / minute.

During the above, the aluminum alloy material 1 is brought into contact with the bottom surface 21a of the main body 21 in the first portion 20a and the probe base end portion 22 to generate frictional heat and to be plasticized and fluidized. Also, it comes into contact with the probe tip portion 24 of the second portion 20b and generates heat due to friction, causing plasticity and fluidization. As a result, the aluminum alloy material 1 and the oxygen-free copper 2 are agitated with each other, and a joining portion W is formed in which both metals are solidified in a mixed state as the joining tool 20 is separated. On the other hand, the oxygen-free copper 2 comes into frictional contact with the probe tip 24 of the second portion 20b, and the calorific value increases in accordance with the increase in the number of revolutions, so that the insufficient flow can be eliminated. This makes it possible to form a sound joint W without internal defects (cavities) along the overlapped portion 4.

[0040]

Examples 10 to 12 Here, specific examples of the third joining method will be described together with comparative examples. JIS: Made of A6063, length 200mm x width 100
Four sets of an aluminum alloy material 1 having a size of 5 mm and a thickness of 5 mm and oxygen-free copper 2 having the same size were prepared. Also, a first portion 20a formed of high-speed steel and having a main body 21 having a diameter of 20 mm and a probe base end 22 having a diameter of 9 mm and a length of 3 mm.
And a second part 20b comprising a probe tip 24 and a rotating shaft 26 of the same diameter and length.
Was prepared. Further, the joining tool 10 shown in FIG. 1 was separately prepared. As shown in FIGS. 4 (C) and 4 (D), each set of the aluminum alloy material 1 and the oxygen-free copper 2 are overlapped and restrained to form the overlapped portion 4 and the aluminum alloy material 1 The joining tool 20 and the joining tool 10 were individually arranged near the surface and inclined in the same manner as described above.

The first and second portions 20a and 20b of the welding tool 20 which are inclined from the surface side of the three sets of aluminum alloy materials 1 by 5 ° in the direction opposite to the moving direction are individually rotated at the rotation speeds shown in Table 4, Inserting under the same conditions of a pushing pressure of 12.5 kN and a moving speed of 200 mm / min.
As shown in (C) and (D), it was moved along the overlapping section 4. The joints W obtained by these methods were used in Examples 10 to 12
And On the other hand, using the joining tool 10 of FIG. 1 and inserting the remaining aluminum alloy material 1 from the front side under the same conditions as above except that the rotation speed is the same as that of the first portion 20a, In addition, by moving along the overlapping portion 4, the obtained joint W was used as Comparative Example 4. Each joint W of Examples 10 to 12 and Comparative Example 4 was cut, and the exposed cross section was visually observed to check for defects. Table 4 shows the results.

[0042]

[Table 4]

According to the results shown in Table 4, the joints W of Examples 10 to 12 did not have internal defects, whereas the joints W of Comparative Example 4 had a coarse size of about 0.2 mm. Internal defects
(Cavity) was discovered. That is, in Examples 10 to 12, the second portion 20b of the welding tool 20 having a large number of rotations caused sufficient plastic flow even in the oxygen-free copper 2 and did not cause insufficient flow. On the other hand, in Comparative Example 4, the single probe 12 was rotated at the same rotational speed in the aluminum material 1 and the oxygen-free copper 2 to stir them.
It is presumed that insufficient flow occurred in the oxygen-free copper 2. The advantages of the third joining method can be easily understood from Examples 10 to 12 described above.

FIGS. 5A and 5B show a joining tool (corresponding to claim 6) 20 'having a different configuration. As shown,
The joining tool 20 ′ includes a first portion 20 a including a cylindrical main body 21, a second portion 20 b including a rotating shaft 26 penetrating through an axial hole 23 of the main body 21 and a probe 25 located at the tip thereof. Such a first portion 20a and a second portion 20b
And a plurality of bearings 28 disposed between them. The first and second parts 20a and 20b are individually connected to a dedicated driving source such as a motor, and are connected to the first and second parts 20a and 20b.
A heat-resistant sealing material 29 is arranged near the outer end between the points b. Even when using the joining tool 20 'as described above,
The rotation speed of the second portion 20b including the probe 25 is
As shown in FIGS. 4C and 4D, the amount of heat input due to friction increases, and plasticity and fluidization of the copper member 2 on the high melting point side are increased as shown in FIGS. It is done reliably. On the other hand, since the rotation speed of the first portion 20a is reduced, the aluminum alloy material 1 on the low melting point side in contact with the bottom surface 21a of the main body 21 can be prevented from melting due to excessive frictional heat generation. Therefore, a sound joining portion W can be formed by the joining tool 20 '.

FIG. 5 (C) shows a cross section of a welding tool (corresponding to claim 6) 20 "having a different form. The welding tool 20" has a cylindrical shape as shown in FIG. 5 (C). A first portion 20a including an outer peripheral portion of a main body 21, a large-diameter rotary shaft 26 penetrating through an axial hole 23 of the main body 21, and a bottom surface 27 thereof.
Including a probe 25 protruding coaxially from the center of the second
It includes a portion 20b and a plurality of bearings 28 disposed between the first portion 20a and the second portion 20b. These first
The second parts 20a and 20b are also individually connected to a dedicated driving source such as a motor, and the first and second parts 20a and 20b
A heat-resistant sealing material 29 is arranged near the outer end between the portions 20b. Even if the above joining tool 20 ″ is used,
Like the welding tool 20 ', the operation and effect of the welding tool 20 can be obtained similarly.

The present invention is not limited to the embodiments and examples described above. For example, the metal member on the low melting point side and the high melting point side in the present invention has a difference in melting point or softening point of 100 ° C. or more, or a difference in strength such as tensile strength at the same heating temperature. 100N
If the difference is not less than 30 Hv, or the difference between the hardness is 30 Hv or more, the combination of different metals and their alloys can be applied to the alloys of the same kind of metal rather than the base. In addition, the superposed portion of the pair of metal members on the low melting point side and the high melting point side includes between the step portions of both members or a male-female fitting portion, and is not limited to a linear shape in plan view, An overlapping portion that is bent in the middle or an overlapping portion that curves is also included. Further, the backing material 8
Is not limited to the heater wire 9, but a radiant pipe, a heat pipe, a radiant tube having a built-in burner, or the like can be applied. The uneven portion provided at the distal end of the probe 12 of the joining tool 10 also includes a screw thread engraved on the peripheral surface and a spiral ridge protruding from the distal end surface 12a.

[0047]

According to the first joining method of the present invention described above (claim 1), the frictional heat of the metal member on the high melting point side which comes into contact with only the vicinity of the probe tip in the joining tool is directed to the back side. Escape is prevented, and a decrease in temperature in the flow / stirring portion of the metal member on the high melting point side can be suppressed. For this reason, the shortage of flow in the metal member on the high melting point side is eliminated, and in the vicinity of the overlapping portion between the two metal members having low and high melting points, the two metals are stirred while being plastically flowing with each other. Therefore, it is possible to perform friction stir welding that forms a sound joint without internal defects and surface defects. Further, according to the second joining method (claim 3), the frictional heat of the metal member on the high melting point side which comes into contact with only the vicinity of the probe tip of the joining tool increases in accordance with the increase in the contact area due to the unevenness of the probe tip. Increase. For this reason, the lack of flow in the metal member on the high melting point side is eliminated, so that there is no internal defect near the overlapped portion of both metal members and there is no sound defect on the surface of the metal member on the low melting point side. Can be obtained.

Further, according to the third joining method (claims 4 and 5), since the rotation speed of the second portion in the joining tool is high, the metal on the high melting point side in contact with the probe of the portion or the vicinity of the tip thereof. Insufficient flow in the member is eliminated. For this reason, it is possible to reliably form a sound joint having no internal defect and no surface defect over the overlapped portion of the two metal members. In addition, according to the joining tool used in the third joining method (claims 6 and 7), the probe or the second portion of the probe distal end in the joining tool is more reliable than the first portion of the main body or the probe proximal end. Because of the high speed rotation, it is possible to reliably form a sound joint having no internal defect and no surface defect over the overlapped portion of the two metal members.

[Brief description of the drawings]

FIGS. 1A and 1B are front views schematically showing a first joining method according to the present invention, and FIGS. 1A and 1B are side views thereof.

FIGS. 2A and 2B are front views schematically showing an application form of a first joining method according to the present invention, and FIGS. 2A and 2B are side views of these.

FIGS. 3A and 3B are side views or perspective views of a welding tool used in a second welding method according to the present invention; FIGS. 3C and 3D are bottom views showing uneven portions having different shapes; (c) is a side view of the form of (C), (d) is a cross-sectional view at a viewing angle along the line dd in (D), and (E) and (F) show side views of a joining tool having further different forms. The figure or a perspective view, (e) is sectional drawing in the viewing angle along ee line in (E).

FIGS. 4A and 4B are side views or cross-sectional views of a welding tool used in a third welding method according to the present invention, and FIGS. 4C and 4D are schematic views showing the third welding method.

FIGS. 5A and 5B are side views or cross-sectional views of different types of welding tools used in a third welding method, and FIG. 5C is a cross-sectional view of a different welding tool.

FIG. 6A is a schematic view showing a conventional friction stir welding.
(B), (C) is sectional drawing which shows the vicinity of the joining part obtained by this.

[Explanation of symbols]

1 ... Aluminum alloy material (low melting point metal member) 2 ... Oxygen free copper (high melting point metal member) 4 ... ............ Overlapping part 6, 8 ...... Backing material 9 ...... Heater wire (heating means) 10, 20, 20 ', 20 "joining tool 11, 21 ... body 11a, 21a ... bottom surface 12, 25 ... probe 12a ... …………………………………………………………………………………………………………………………………………………………. ...... Projections (irregularities) 17, 18, 19 ... Ring ridges (irregularities) 20a ...... First part 20b ............ ... Second part 22.............. ........................... probe tip 26 ................................. rotary shaft 28 ................................. bearing

Claims (7)

[Claims] 1. A step of superposing a pair of metal members having different melting points from each other; and a cylindrical main body near the surface of the metal member on the low melting point side of the pair of metal members, and a probe protruding from the bottom surface thereof. Arranging a joining tool having the above, and arranging a backing material near the back surface of the metal member on the high melting point side facing the joining tool; and near the overlapping portion of the pair of metal members while rotating the joining tool. And welding the pair of metal members along the overlapping portion by friction stir welding by moving the pair of metal members along a longitudinal direction of the overlapping portion. 2. The joint according to claim 1, wherein the backing material has a lower thermal conductivity than the metal member on the high melting point side, or has a heating means. Method. 3. A joining method using a joining tool having a cylindrical main body and a probe on a bottom surface thereof and having an uneven portion at the tip of the probe, wherein a pair of metal members having different melting points are overlapped. A step of arranging the joining tool near the surface of the metal member on the low melting point side of the pair of metal members; and causing the joining tool to approach the overlapping portion of the pair of metal members while rotating the joining tool; A step of moving the pair of metal members along the overlapping portion by friction stir welding by moving the overlapping portion along the longitudinal direction. 4. A first portion including at least an outer peripheral portion of a cylindrical main body, and a second portion including at least a probe tip.
A joining method comprising using a joining tool comprising a first part and a second part, wherein the first part and the second part are coaxial and individually rotate, and a step of superposing a pair of metal members having different melting points from each other; Arranging the welding tool near the surface of the metal member on the low melting point side of the member, and rotating the welding tool with the rotation speed of the second portion thereof being higher than the rotation speed of the first portion. Causing the pair of metal members to enter the vicinity of the overlapped portion of the pair of metal members and to move along the longitudinal direction of the overlapped portion to thereby frictionally stir the pair of metal members along the overlapped portion. The joining method characterized by the above-mentioned. 5. The probe according to claim 1, wherein the first portion includes a cylindrical main body and a probe base end protruding from the bottom surface thereof, and the second portion includes a probe tip end, and coaxially and individually rotates with each other. A joining method using a joining tool including first and second portions, wherein a step of superposing a pair of metal members having different melting points from each other; Disposing the welding tool on the probe, and rotating the welding tool with the rotation speed of the second portion closer to the probe tip than the rotation speed of the first portion on the body side of the pair of metal members. Causing the pair of metal members to undergo friction stir welding along the overlapped portion by entering near the overlapped portion and moving along the longitudinal direction of the overlapped portion. Noted in 4 Mounting method. 6. A joining tool for use in the joining method according to claim 4, wherein the first portion includes a cylindrical main body or an outer peripheral portion of the main body, and a rotation penetrating coaxially through a central portion of the main body. A second portion including a shaft, a probe located at a tip of the rotating shaft and protruding from a bottom surface of the main body, and a bearing disposed between the first portion and the second portion. And joining tools. 7. A joining tool used in the joining method according to claim 5, wherein the first portion includes a cylindrical main body and a probe base end protruding from a bottom surface thereof; A second part including a main body of one part and a rotating shaft penetrating an axis of a base end portion of the probe; and a bearing disposed between the first part and the second part. Joining tools.