JP2002066760A - Joining method of metal and joining device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a deburring process after joining of a metal member. SOLUTION: In a joining device of metal where the first metal member W1 and the second metal member W2 are lapped and joined by a frictional agitation in non-melted state, a rotational member 1, which processes a surface part where the joining part of the second metal member W2 corresponds to the first metal member W1 while rotating, and a removal measure 1b, which removes a burr generated at the peripheral of the rotation member 1 in the first metal member, are provided. The joining device is equipped with control measure to control the rotational member 1 to join the first and second metal member W1, W2 by a frictional agitation at the joining part of the first and second metallic member W1, W2, using the rotational member 1 and the removal measure 1b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for joining metals such as aluminum alloy castings and sheet materials.

[0002]

2. Description of the Related Art In the conventional joining technique, a sheet material or a metal member which has been previously press-formed into a three-dimensional shape is overlapped and joined by electric resistance welding, arc welding, adhesive, bolt fastening, rivets, or the like.

[0003] When the metal member has a complicated three-dimensional shape, spot welding that can be locally joined to a plurality of joints is used.

[0004] As another joining technique, a joining method of friction stirring in a non-molten state is disclosed in Japanese Patent No. 2712838. In this joining technique, a projection called a probe is rotated and inserted and translated into a joining surface where two members are joined to each other, and the metal structure near the joining surface is plasticized by frictional heat and joined.

[0005]

However, when the joining technique described in the above publication is applied to overlap joining of metal members, burrs are generated around the rotating member in the metal member due to the pressing of the rotating member, and the joining of the members is performed. Later, it was necessary to perform deburring separately on the bonding surface.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a metal bonding method and a metal bonding apparatus which can simplify a deburring step after bonding a metal member.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems and achieve the object, a method of joining metals according to the present invention comprises the following steps.
In a metal joining method in which a metal member and a second metal member are overlapped and agitated by friction in a non-molten state and joined, a surface corresponding to a joint portion of the first metal member with the second metal member is provided. The rotating member is pressed against the portion, and the rotation of the rotating member causes the joint portion of the first and second metal members to be stirred by friction in a non-molten state, and the rotation and pressing of the rotating member cause the first metal member to rotate. The first and second metal members are joined together while removing the burrs generated around the rotating member in the above.

[0008] Preferably, a tip of the rotating member is formed in a flat shape.

Preferably, a flash removing means for forming a step with respect to the tip of the rotary member is provided on the outer periphery of the rotary member.

The metal joining apparatus according to the present invention is a metal joining apparatus in which a first metal member and a second metal member are overlapped with each other and joined by stirring in a non-molten state by friction. A rotating member that presses while rotating a surface portion corresponding to a joint portion with the second metal member in the above, and a periphery of the rotating member in the first metal member that is pressed by the rotating member in synchronization with the rotating member. The first and second metal members are joined by frictionally agitating the joining portion of the first and second metal members in a non-molten state by a removing means for removing burrs generated on the substrate and the rotating member. Control means for controlling the rotating member.

[0011]

As described above, according to the first and fourth aspects of the present invention, the rotating member is pressed against the surface of the first metal member corresponding to the joint portion with the second metal member. By rotating, the joining portion of the first and second metal members is agitated by friction in a non-molten state in a non-molten state, while removing burrs generated around the rotating member in the first metal member due to rotation and pressing of the rotating member, By joining the first and second metal members, the deburring step after joining the metal members can be simplified.

According to the second aspect of the present invention, since the tip of the rotating member is formed in a flat shape, no hole remains as a joint mark, and machining of a tool can be performed easily and at low cost.

According to the third aspect of the present invention, the burrs are crushed after the metal members are joined by providing the burr removing means on the outer periphery of the rotating member to form a step with respect to the tip of the rotating member. Therefore, no chips are generated and the tool can be manufactured at low cost.

[0014]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

The embodiment described below is an example as a means for realizing the present invention, and the present invention can be applied to a modification or modification of the following embodiment without departing from the gist thereof. .

FIG. 1 is an enlarged view of the vicinity of a rotary tool for explaining an overlap joining method according to an embodiment of the present invention.

The joining method of the present embodiment is applied to joining of a plate material made of an aluminum alloy or a metal member that has been press-formed into a three-dimensional shape in advance. By pressing the rotary tool 1 against the one metal member W1, the metal structure between the superposed first and second metal members W1, W2 is agitated in a non-melting manner by frictional heat and joined.

Since the stirring is performed in a non-melting state, problems such as thermal distortion generated by electric resistance welding or the like can be solved.

Here, the non-melting and stirring state means that the metal structure is softened by frictional heat at a temperature lower than the lowest melting point among the components or eutectic compounds contained in the base material. Means to stir.

As shown in FIG. 1, in the joining method by friction stirring, at least two metal members W1 and W2 are overlapped, and a cylindrical rotary tool 1 having a flat tip 3 is placed around its axis. While rotating, the tip 3 is pressed against the first metal member W1 on the outermost surface, and the first metal members W1 and W2 are stirred by friction in a non-molten state to form a non-melted stirrer layer. The first and second metal members W1, W2 are joined by expanding the non-melting friction stir layer to the metal member W2.

In the conventional butt joint, the metal structure is softened by the probe and the softened metal structure is suppressed by the shoulder, whereas in the lap joint of the present embodiment, the tip portion 3 softens the metal structure and causes plastic flow. It has a function to make it work.

A receiving member 4 is disposed so as to face the distal end portion 3 of the rotary tool 1 so as to sandwich the first and second metal members W1 and W2. The outer diameter of the receiving member 4 is designed to be larger than the outer diameter of the rotary tool 1.

The rotary tool 1 has a diameter φ1 of about 10 to 15 mm. The rotary tool 1 and the receiving member 4 are non-wear type tools formed of a steel material (hard metal or the like) having a higher hardness than the metal member. It is not limited to alloys.

As shown in FIG. 2, the rotary tool 1
A concave portion 3 a is formed substantially at the center of the tip portion 3. Also,
A recess 5 a is also formed substantially at the center of the tip 5 of the receiving member 4.

The recess 3a of the rotary tool 1 and the recess 5a of the receiving member 4 can be provided in one or both. Further, a pin-shaped convex portion may be provided instead of the concave portion 3a.

FIGS. 3 to 5 are diagrams illustrating other shapes of the distal end portion 3 of the rotary tool 1, wherein (a) is a side view and (b).
Is a front view of the tip.

The rotating tool 1 shown in FIG. 3 has a tip 3 formed to be inclined with respect to the contact surface with the metal member, and is configured so that the height from the contact surface changes. In addition, the rotating tool 1 shown in FIG. 4 has a plurality of projections radially extending from the center of the tip toward the outer circumference so that the height of the tip 3 is different in the circumferential direction. A portion (or a groove) 3b is formed. The rotary tool 1 shown in FIG. 5 has a flat tip 3 so that the height of the tip 3 is different in the circumferential direction.
At least 1 from the center of the tip to the outer periphery.
Three grooves (or protrusions) 3c are formed.

The rotary tool 1 only needs to be able to form irregularities or waves in the circumferential direction of the tip.
a and the shape of the distal end portion 3 shown in FIGS. 3 to 5, or the shapes shown in FIGS. 4 and 5 can be configured by combining the protrusion and the groove. If the height of the protruding portion or the depth of the groove portion is too large, the agitation of the metal structure deteriorates, which is not suitable.

The rotary tool 1 is rotatably mounted on an arm of the articulated robot 10 described below, and when the metal member to be bonded has a complicated three-dimensional shape, a spot is formed on a plurality of joints. It is configured so that it can be joined locally (locally).

FIG. 6 is a schematic diagram of an articulated robot that holds and drives a rotary tool.

As shown in FIG. 6, the articulated robot 10
Is connected to a joint 12 provided on a base 11 and swings about a y-axis, and is rotated by a joint 13 about a z-axis. The first arm 14 is connected to a first arm 14 via a joint 15. A second arm 17 swinging about the y-axis and rotating about the x-axis at a joint 16, and a third arm 19 connected to the second arm 17 via a joint 18 and swinging about the y-axis. Having.

The third arm 19 includes a motor 20 for rotatably mounting the rotary tool 1, a motor 20 for rotating the rotary tool 1, and a receiving member 4 arranged to face the tip 3 of the rotary tool 1. Prepare. The distance between the distal end 3 of the rotary tool 1 and the distal end of the receiving member 4 is variable by the actuator 22, and is designed so as to be able to cope with the pressing force against the metal members at the time of joining and the metal members stacked three or more. ing.

Each arm, motor,
The operation of the actuator is previously taught and controlled by the control unit 30.

The pressing force of the rotary tool 1 against the metal member is
It is set for each joint based on the total plate thickness of the metal members, the number of sheets to be superimposed, and the like, and can be applied to the case where the plate thickness of each metal member is different.

As shown in FIG. 7, three or more first
When joining the third to third metal members W1 to W3, the metal members are sandwiched and joined by a pair of rotary tools 1A and 1B having the same outer diameter. In this case, the rotary tool 1B is rotatably attached to the articulated robot 10 in place of the receiving member 4 of FIG. 2, and the distal end portions 3 of the rotary tools 1A and 1B opposed to each other.
While rotating the first to third metal members W1 to W3 with A and 3B, the rotary tools 1A and 1B are rotated in reverse.

The joining can be performed even when the first and second metal members W1 and W2 have different plate thicknesses. In particular, when the rotary tool 1 is pressed from the thin side, the stirring becomes easier.
Uniform bonding processing can be realized. [Plastic Flow of Metal Structure at the Time of Joining] FIG. 8 is a diagram showing a state of plastic flow inside the metal member when the tip of the rotary tool is smooth. FIG. 9 is a diagram showing a plastic flow state inside the metal member when a concave portion is formed at the tip of the rotary tool. FIG. 10 is a diagram illustrating a plastic flow state inside the metal member when a protruding portion or a groove is formed at the tip of the rotary tool.

As shown in FIG. 8, when the rotating tool 1 having a smooth distal end 3 is used (the distal end 5 of the receiving member 4 is smooth for convenience of explanation), the rotating tool 1 rotating at a predetermined rotation speed is used.
Is pressed substantially perpendicularly to the first metal member W1, friction occurs between the rotary tool 1 and the first metal member W1, the surface thereof is softened, and the first and second metal members W1, W2 The metal structure between them is stirred in the rotational direction in a non-molten state. When the pressing force of the rotating tool 1 against the first metal member W1 is further increased, the non-melting friction stir layer is expanded to the metal member W2 that is not in contact with the rotating tool 1, and is finally overlapped. The first and second metal members W1, W2 are joined without being melted.

As shown in FIG. 9, when the rotary tool 1 having the concave portion 3a formed in the distal end portion 3 is used (the distal end portion 5 of the receiving member 4 is smooth for convenience of explanation), the metal structure is While being agitated in the rotation direction of the tool 1, the vertical direction (direction intersecting the joining surface of the metal member) immediately below and around the concave portion 3a.
A three-dimensional vertical vortex plastic flow is generated and agitated, and finally the first and second metal members W1, W2 superimposed.
Are joined without being melted.

The concave portion 3a of the rotary tool 1 promotes plastic flow in the concave portion where the peripheral speed of the metal structure to be agitated becomes substantially zero, and when the concave portion 5a of the receiving member 4 is provided, the rotary tool 1 It promotes plastic flow of metal members that do not come into contact with.

Further, as shown in FIG. 10, when the rotary tool 1 having the protruding portion (or groove) 3b formed on the tip 3 is used (the tip 5 of the receiving member 4 is smooth for convenience of explanation). ), The metal structure is agitated in the rotational direction of the tool 1 by the radial unevenness of the tip 3 and the first metal member W
At the interface between the first metal member W2 and the second metal member W2, a plastic flow is added in a vertical direction (a direction intersecting the joining surface of the metal members) that periodically changes in accordance with the rotation. Diffusion at the interface of the metal members is promoted, and the first and second metal members W1, W2 that are finally superimposed are joined without being melted.

As described above, when the concave portion 3a is provided in the distal end portion 3 of the rotary tool 1, all the metal structures to be joined are sufficiently stirred to increase the joining strength, whereas the concave portion 3a is provided. In the case where the metal member is smooth without being provided, the agitation in the direction intersecting with the bonding surface of the metal member is insufficient, so that the bonding strength is weak.

When the rotary tool 1 is formed with irregularities radially, the state of contact of the tip of the rotary tool 1 with the metal structure is different from the case where the recess 3a is formed, and the rotary tool 1 is stirred at the center. Since the angular velocity of the metal structure can be set to be smaller than the angular velocity of the peripheral part, the stirring performance is high,
There is an advantage that a three-dimensional plastic flow in the rotational direction and the vertical direction is easily generated in a wide range of the tip. [Test Results] In the joining process of the present embodiment, a 6000 series steel sheet (Al-Mg-Si steel sheet) standardized by JIS is used as an example of a metal member, but a 5000 series steel sheet (Al-Mg steel sheet) and other A metal member is also applicable.

FIG. 11 is a diagram showing a method for testing the bonding strength by non-melting friction stirring in the present embodiment. FIG.
It is a figure showing the result by the joining strength test method of No. 1.

The joint strength test shown in FIG.
The second metal member W1 and the second metal member W2 are pulled in directions opposite to each other, and the tensile force at the time when the bonding surface is separated is measured as the bonding strength.

The joining condition is that the tool rotation speed is 2000
rpm, the diameter of the tip portion 3 of the rotary tool 1 was 10 mm in diameter, the pressing and holding time was 0.2 mm, the time after pressing, the metal member used was 6000 series, and the plate thickness was 1 mm.

As shown in FIG. 12, the tip 3 has a recess 3a.
The use of the rotary tool 1 on which the joints are formed increases the joining strength and satisfies the required strength as compared with a case where the tip 3 is a smooth tool.

When the tip 3 is a smooth tool,
As shown in FIG. 15, when the metal member is peeled off at the time of destruction, the distal end portion 3 has a concave portion 3a.
13 and FIG. 14 when the tool with
As shown in FIG. 7, the joint surface does not peel off at the time of destruction, and the button breaks from the portion Wa corresponding to the periphery of the rotary tool 1, so that the joint strength is high.

Further, as shown in FIGS. 16 to 19, when joining is performed using a tool having a concave portion 3a formed at the distal end portion 3, the joining is sufficiently stirred so that the joining interface of the metallographic structure becomes uniform. Therefore, the bonding strength is increased.

The longer the pressing and holding time of the rotary tool 1 against the metal member, the higher the bonding strength becomes. However, when the rotary tool 1 is pressed and held for about 10 seconds or more, when the rotary tool 1 having the concave portion 3a at the tip 3 is used. However, even when the tip 3 is a smooth tool, the joining strength is substantially the same. [Joining with an alloy material interposed] The first and second metal members can be joined with an alloy material interposed between the two metal members.

FIG. 20 is a view for explaining a method of joining the first and second metal members with an alloy material interposed. FIG.
FIG. 4 is a view for explaining a state in which an alloy material is diffused at a joint portion P between the first and second metal members.

As shown in FIGS. 20 and 21, for example,
The first metal member W1 is an aluminum alloy plate, and the second metal member W2 has a Zn-5Al layer or a Zn hot-dip layer Wc formed as an alloy material via a Zn-Fe-Al or Zn-Fe alloy layer Wd. It is an Fe steel plate. Zn-5Al
The layer consists of a eutectic composition of about 95% by weight Zn component and about 5% by weight Al component. Preferably, an aluminum alloy coated with a Zn-5Al alloy material is most suitable. The Zn hot-dip plating layer is generally commercially available in a state of being coated with a metal member for rust prevention.

The first and second metal members W1 and W2 are overlapped with each other via a Zn-5Al layer or a Zn hot-dip layer Wc as an alloy material, and a joining portion P of the first metal member W1 with the second metal member W2 is formed. When the rotating tool 1 is pressed against the surface portion corresponding to the above, the aluminum alloy is stirred by friction and starts plastic flow. When plastic flow is promoted, the oxide film on the surface of the aluminum alloy is broken, and Z
The n-5Al layer or Zn hot-dip layer Wc and the aluminum alloy diffuse into each other, and Al, Al-Zn, Zn-A
1, a diffusion layer composed of Fe-Zn and Fe is formed, and further, plastic flow is promoted to form an Al-Zn-Fe alloy layer We, and the aluminum alloy sheet W1 and the steel sheet W2 are formed of Al-Zn.
-Joined via the Fe alloy layer We.

When a steel sheet not covered with the Zn-5Al layer or the Zn hot-dip layer Wc is joined to an aluminum alloy sheet, the joining part P of the two members is joined to the Zn-5Al layer.
A layer or an alloy material such as a Zn alloy foil may be separately provided. Further, in addition to Zn-Al as an alloy material, Mg-A
An alloy material may be formed.

The rotating tool 1 has a flat tip end,
Tools of various shapes described above can be used. Alternatively, a rotating tool having a protruding portion 2 called a probe at the tip may be used.

The rotary tool 1 is pressed from the lower melting point of the first metal member W1 and the second metal member W2 to stir by friction.

Thus, by pressing the rotating tool from the aluminum alloy side, which softens with less heat input, than the steel sheet having a higher melting point and high-temperature strength than the aluminum alloy, the joining can be performed in a short time, and Since the thermal and mechanical loads can be reduced, there is an advantage that the tool life can be extended.

As shown in FIGS. 22 to 25, the number of rotations of the rotary tool 1 to the metal member is constant at about 1000 rpm (FIGS. 22 and 23) or in order to promote the destruction of the oxide film of the aluminum alloy. It may be changed periodically (FIGS. 24 and 25). Decreasing the number of revolutions is not preferable because it takes time for joining.

The pressing force of the rotary tool 1 against the metal member is constant (FIGS. 22 and 24) or gradually increased (FIGS. 23 and 2).
5). As the pressing force is reduced, the plastic flow becomes insufficient, and sufficient bonding strength cannot be obtained.

As for the relationship between the number of rotations and the pressing force, it is necessary to increase the pressing force as the metal structure is softened. [Diffusion Bonding of Alloy Material] FIGS.
-5 Al layer and aluminum alloy diffuse into each other and A
A diffusion layer composed of 1, Al-Zn, Zn-Al, Fe-Zn, and Fe is formed.
The aluminum alloy plate W1 becomes the Zn—Fe alloy layer We.
FIG. 5 is a view showing a state in which a steel sheet W2 is joined to a steel sheet W2 via an Al—Zn—Fe alloy layer We.

When the aluminum alloy plate and the Fe steel plate shown in FIG. 26 (a) are superposed with the Zn-5Al layer interposed therebetween and are frictionally stirred in a non-melting manner by the rotary tool 1,
As shown in FIG. 26 (b), a diffusion layer composed of Al and Zn-5Al layers is formed below the aluminum alloy, and a diffusion layer composed of Fe and Zn-5Al layers is formed above the Fe steel plate. .

Further, as the plastic flow proceeds by stirring, the Zn component of the Zn-5Al layer further diffuses into the aluminum alloy and the Fe steel as shown in FIG. 26 (c), and the Zn-5Al The ratio of the Zn component in the layer decreases (the ratio of the Al component increases).

Next, from the state shown in FIG. 26 (c), the plastic flow further proceeds, so that a diffusion reaction between the diffusion layer on the aluminum alloy side and the diffusion layer on the Fe steel sheet side is performed. As a result, FIG. An Al-Zn-Fe alloy layer shown in d) is formed.

As described above, the first and second metal members W
1 and W2 are joined via a three-element alloy layer of Al-Zn-Fe. Thereby, the first and second metal members W
1, W2 can prevent the formation of a brittle intermetallic compound called Fe-Al on its joint surface,
The bonding strength can be extremely increased by the three-element alloy layer of l-Zn. [Metal Member Shape] This embodiment is suitable for joining a metal member that has been press-formed into a three-dimensional shape in advance. That is, like the joining of the vehicle body frame W1 and the reinforcing member W2 of the automobile shown in FIG. By using the joining method of the present embodiment, the joining portion P can be locally welded, and can be joined even after press forming. [Burr Removal Structure] FIG. 28 is a view showing a tip of a rotary tool provided with a cutting tip on the rotary tool. FIG. 29 is a diagram illustrating a tip portion of a rotating tool provided with a burr suppressing step in the rotating tool.

As shown in FIGS. 28 and 29, in order to remove the burrs Wb (see FIG. 13) generated on the metal member at the time of joining, as shown in FIGS. The burr suppressing step 1b may be formed integrally or later.

The cutting tips 1 b are in a plane parallel to the tip 3, and are provided on the outer peripheral surface near the tip of the rotary tool 1 at equal intervals of 90 °. In addition, the cutting tip 1b is
Instead of a planar shape, for example, a spiral cutting blade shape can be used, and the number of chips can be arbitrarily set according to the components of the metal member and the amount of pushing.

The burr suppressing step 1c is formed in a flat shape parallel to the distal end portion 3 and on the outer peripheral surface near the distal end of the rotary tool 1 over the entire circumference.

FIG. 31 is a view for explaining a deburring method when a cutting tip is provided on a rotary tool. FIG.
It is a figure explaining a deburring method when a rotating tool is provided with a burr-suppression step.

When the burrs Wb are removed by the cutting tip 1b, as shown in FIG. 31, the burrs Wb generated around the rotary tool 1 in the first metal member W1 by the rotation and pressing of the rotary tool 1 are cut. Remove.

When the burr Wb is removed by the burr suppressing step 1c, as shown in FIG. 32, the burr Wb generated around the rotating tool 1 in the first metal member W1 by the rotation and pressing of the rotating tool 1 is crushed. Remove.

As shown in FIG. 30, the position of the cutting tip 1b or the burr suppressing step 1c in the axial direction is formed upward by the pushing amount t of the tip 3 pushed into the metal member W1.

In the cutting tip 1b, although burrs can be completely removed, chips Wb are generated, and the rotary tool 1 is expensive because the hard cutting tip 1b is used. On the other hand, in the burr suppressing step 1c, the appearance is slightly inferior because the crushed burr Wb remains, but there is an advantage that the rotary tool 1 is inexpensive and no chips are generated.

Further, the cutting tip 1b or the burr suppressing step 1c is not fixed to the rotary tool 1, but the rotary tool 1
May be configured to be able to ascend and descend coaxially with the rotation axis of.

FIG. 33 is a view showing an example in which the cutting tip 1b or the burr suppressing step 1c is provided so as to be able to move up and down with respect to the rotary tool, and a burr removing method.

As shown in FIG. 33, the cutting tip 1b or the burr suppressing step 1c is coaxial with the rotary shaft of the rotary tool 1, and is a hollow shaft which can be raised and lowered with respect to the outer peripheral surface (or may be rotatable). 41 are provided at the tip.

When the burr Wb is removed by the vertically movable cutting tip 1b or the burr suppressing step 1c, FIG.
At the time of joining shown in (a) and (b), it is raised and separated from the joining portion, and as shown in FIGS. 33 (c) and (d), after the joining is completed, the cutting tip 1b or the burr suppressing step 1c is lowered. The burrs Wb are removed by cutting or crushing.

Cutting tip 1b or burr suppressing step 1c
Is more complicated and more expensive than the fixed type, but has the advantage that the same tool can be used even when the amount of pushing of the rotary tool is changed according to the metal member. [Continuous Joining] In the above embodiment, an example of spot joining in which the rotating tool 1 is pressed against the joining portion and is not moved has been described. However, as shown in FIG. You may join.

When the rotary tool 1 is advanced in FIG. 34, as shown in FIG.
When the metal member W1 is moved while being inclined, the stirring performance is improved by the amount of the inclination as compared with the case where the metal member W1 is pressed vertically. [Modification] As a modification of the present embodiment, in order to suppress the distortion of the metal members, the metal members can be joined while being cooled. As a cooling method, bonding may be performed in cooling water, or cooling water may be supplied to a bonding portion. [Surface Treatment] The joining technique of the present embodiment can also be applied to the surface treatment of a metal member.

In the surface treatment, an aluminum alloy casting is used. In particular, the aluminum alloy casting is used for surface modification between adjacent ports (valve portions) formed in a cylinder head of an automobile, a piston, a brake disk, and the like. By agitating the surface modified area of the casting without melting it by frictional heat, the metal structure can be refined, the eutectic silicon (Si) particles can be uniformly dispersed, casting defects can be reduced, and thermal fatigue (low cycle fatigue) can be achieved. ) The material properties such as life, elongation, impact resistance and the like can be obtained more than conventional remelt treatment.

In the surface treatment of the present embodiment, FIG.
As shown in FIG. 1, AC4D which is an aluminum alloy standardized by JIS is used as an example. As an aluminum alloy casting, magnesium (M
g) 0.2-1.5% by weight as content, silicon (S
i) The content is 1 to 24% by weight, preferably 4 to 13% by weight.
The composition ratio can be changed within the range of weight%. AC4
B, AC2B, AC8A used for a piston, etc. can also be used. The reason for setting the upper limit of silicon content to 24% is
This is because, even if silicon is further increased, material properties and castability are saturated, and agitation is deteriorated.

An aluminum alloy casting containing magnesium precipitates Mg ₂ Si by heat treatment, thereby increasing strength. However, when the metal structure is refined by melting as in a remelt treatment, magnesium having a low melting point (650 ° C.) may evaporate to reduce the content. When the magnesium content is reduced, the hardness and strength are reduced even if heat treatment is performed, so that desired material properties cannot be obtained.

[0081] On the other hand, the surface treatment by friction stir, since magnesium does not melt the metal structure nor evaporates, Mg ₂ of the aluminum alloy casting heat treatment
The strength is increased by precipitating Si.

By adding silicon to the aluminum alloy, the castability (fluidity of the molten metal, shrinkage properties, hot cracking resistance) is improved, but the eutectic silicon acts as a kind of defect to provide mechanical properties (elongation). ) Decreases.

Eutectic silicon is hard and brittle, and serves as a starting point of crack generation and a propagation path, so that elongation is reduced. In addition, the fatigue life of a portion that is repeatedly subjected to thermal stress, such as an inter-valve portion, is reduced. In the metal structure, eutectic silicon is connected along the dendrite.However, cracking due to stress concentration and propagation of the generated cracks are suppressed by miniaturizing and uniformly dispersing the eutectic silicon. It is possible to do.

FIG. 37 is a view for explaining a surface modification method between adjacent ports (valves) formed in a cylinder head of an automobile as an example of application to the surface treatment.

As shown in FIG. 37, in the surface reforming process, the rotary tool 1 is moved in the inter-valve portion of the adjacent port while stirring by friction so as to longitudinally cut the inter-valve portion along the processing trajectories F1 to F3. Let it.

The present invention can be applied to a modification or modification of the above embodiment without departing from the gist of the invention.

[Brief description of the drawings]

FIG. 1 is an enlarged view of the vicinity of a rotary tool for explaining an overlap joining method according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a method of joining metal members.

FIG. 3

FIG. 4

5A and 5B are diagrams illustrating other shapes of the tip of the rotary tool, wherein FIG. 5A is a side view and FIG. 5B is a front view of the tip.

FIG. 6 is a schematic diagram of an articulated robot that holds and drives a rotary tool.

FIG. 7 is a diagram illustrating a method of joining three or more metal members.

FIG. 8 is a diagram showing a state of plastic flow inside a metal member when the tip of the rotary tool is smooth.

FIG. 9 is a diagram showing a state of plastic flow inside the metal member when a concave portion is formed at the tip of the rotary tool.

FIG. 10 is a diagram showing a state of plastic flow inside a metal member when a protruding portion or a groove is formed at the tip of the rotary tool.

FIG. 11 is a diagram showing a bonding strength test method by non-melting friction stirring of the present embodiment.

FIG. 12 is a diagram showing the results of the bonding strength test method of FIG.

FIG. 13 is a cross-sectional view showing a metal structure of a joint portion of the metal members joined according to the present embodiment.

FIG. 14 is a diagram illustrating a state of a metal member when a button is broken by a bonding strength test.

FIG. 15 is a diagram showing a state of a metal member at the time of peeling breakage in a bonding strength test.

FIG. 16 is a view corresponding to FIG. 13 and showing a cross-sectional photograph of the metal structure of the joint portion of the metal members joined according to the present embodiment.

FIG. 17 is a diagram showing an enlarged photograph of a portion I in FIG. 16;

18 is a view showing a cross-sectional photograph of the metal structure of the metal member of Part II in FIG. 17;

FIG. 19 is a view showing an enlarged photograph of FIG. 18;

FIG. 20 is a diagram illustrating a method for joining the first and second metal members with an alloy material interposed therebetween.

FIG. 21 is a diagram illustrating a state in which an alloy material is diffused at a joint portion P between the first and second metal members.

FIG.

FIG. 23

FIG. 24

FIG. 25 is a diagram illustrating a control example of the rotation speed and the pressing force of the rotary tool in joining metal members.

FIG. 26 shows that a Zn-5Al layer and an aluminum alloy are mutually diffused and Al, Al—Zn, Zn—Al, Fe—Z
A diffusion layer comprising n and Fe is formed, and Al-Zn-Fe
It is a figure which shows a mode that a metal member is joined as an alloy layer.

FIG. 27 is a diagram illustrating a case where a vehicle body frame is joined to a metal member that has been press-formed into a three-dimensional shape in advance.

FIG. 28 is a diagram showing a tip portion of a rotary tool provided with a cutting tip on the rotary tool.

FIG. 29 is a view showing a tip of a rotary tool provided with a burr suppressing step in the rotary tool.

FIG. 30 is a diagram for explaining a mounting position of a cutting tip or a burr suppressing step on a rotary tool.

FIG. 31 is a diagram illustrating a deburring method when a cutting tip is provided on a rotary tool.

FIG. 32 is a diagram illustrating a deburring method when a rotary tool is provided with a burr suppression step.

FIG. 33 is a diagram showing an example in which a cutting tip or a burr suppressing step is provided so as to be able to move up and down with respect to a rotary tool, and a deburring method.

FIG. 34 is an enlarged view of the vicinity of the rotary tool for explaining a case where the rotary tool is continuously joined while being advanced.

FIG. 35 is a diagram illustrating a method of joining metal members when the rotary tool is continuously joined while being advanced.

FIG. 36 is a diagram showing a component ratio of an aluminum alloy casting used for surface treatment.

FIG. 37 is a diagram illustrating a surface modification method between adjacent ports (an inter-valve portion) formed in a cylinder head of an automobile as an example of application to the surface treatment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotary tool 2 Projection part 3 Tip part 4 Receiving member 10 Articulated robot W1-W3 Metal member

Claims (4)

[Claims] 1. A method for joining metals by superimposing a first metal member and a second metal member and agitating and joining them in a non-molten state by friction, wherein the first metal member and the second metal member in the first metal member are joined together. The rotating member is pressed against a surface portion corresponding to the joining portion of the above, and by the rotation of the rotating member, the joining portion of the first and second metal members is stirred by friction in a non-molten state, and the rotation of the rotating member and A method for joining metals, wherein the first and second metal members are joined while removing burrs generated around the rotating member in the first metal member by pressing. 2. The method according to claim 1, wherein a tip of the rotating member is formed in a flat shape. 3. The metal joining method according to claim 1, wherein a burr removing unit that forms a step with respect to a tip of the rotating member is provided on an outer periphery of the rotating member. . 4. A metal joining apparatus for joining a first metal member and a second metal member in a superposed state and agitating them by friction in a non-molten state, wherein the second metal member and the second metal member in the first metal member are joined together. A rotating member that presses while rotating a surface portion corresponding to a joining portion of the first and second members; and, in synchronization with the rotating member, removes a burr generated around the rotating member in the first metal member due to the pressing of the rotating member. The removing unit and the rotating member control the rotating member so as to join the first and second metal members by agitating the joined portion of the first and second metal members in a non-molten state by friction. A metal joining device, comprising: a control unit.