JP2002224859A - Friction stir tool and method for using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a friction stir tool by which a bonding part and an agitating part in which burrs and internal defects or the like hardly occur are easily formed and a method for use such as a bonding method using the tool. SOLUTION: The friction stir tool 1 is provided with a columnar tool main body 2 and an agitating pin 10 which droops from the central part of the bottom surface 3 of the tool main body 2, a ring shaped projecting part 4 is formed near the peripheral edge of the bottom surface 3 of the tool main body 2, a pillar shaped body (projecting body) 8 which droops nearer to the bottom surface 3 than the ring shaped projecting part 4 is formed between the ring shaped projecting part 4 and the agitating pin 10 and also an outside metal pool part 6 is positioned between the ring shaped projecting part 4 and the pillar shaped body 8, and moreover an inside metal pool part 9 is positioned in the bottom surface 3 side of the pillar shaped body 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction stir tool used for joining a pair of metal members by friction stir welding or removing fine voids in a surface layer of a casting and a method of using the same.

[0002]

2. Description of the Related Art A friction stir welding method has been used as a method for joining or overlapping a pair of metal members in a solid state. Conventionally, the following friction stir tool 50 has been used in this method. This tool 5
As shown in FIGS. 8 (A) and 8 (B), reference numeral 0 denotes an integral body made of tool steel, which is a cylindrical tool main body 52, a bottom surface 53 in which the center of the main body 52 is concave upward, and a bottom surface 53 includes a recess 54 and a stirring pin 56 hanging coaxially with the tool body 52 from the center of the bottom surface 53. Recess 5
At 4, the inclination angle from the periphery of the bottom surface 53 toward the center was generally 10 ° or less. Further, the stirring pin 56 has a screw portion 58 near the distal end surface 57 thereof.

As shown in FIG. 8C, a pair of metal members M
A friction stir tool 50 along the butt surface F of the M1 and M2
8 is rotated at a high speed, and the stirring pin 56 is inserted.
It is moved along the direction shown by the oblique arrow in (C).
At this time, the tool 50 is moved 3 to 5 on the side opposite to the moving direction.
The metal member M is inclined and the bottom surface 53 side of the tool body 52 is
1 and M2, a pushing force is applied along the axial direction of the tool main body 52. Metal member M1,
As shown in FIG. 8 (C), the metal near the abutting surface F of M2 is softened and flows and agitated by frictional heat with the agitating pin 56 moving while rotating, and then passes through the agitating pin 56. It loses heat and solidifies. As a result, the metal forms a joint S along the abutting surface F.
During this time, a part of the metal once enters the recess 54, and then shifts to the rear of the stirring pin 56 that has been located immediately before, and then solidifies to form the joint S. As a result, the metal members M1 and M2 are joined along the butt surface F. The surface S1 of the joint S is formed with a shallow dent due to the pressing of the tool body 52 and a continuous arc pattern following the rotation locus of the bottom surface 53 of the tool 50.

When the friction stir tool 50 is pushed in excessively, the plasticized fluidized metal is pushed out from the bottom surface 53 of the tool body 52, and as shown in FIG. b is formed along both sides of the surface of the joint S, and the recess h formed on the surface of the joint S increases. For this reason, there has been a problem that the cross-sectional area of the joint S is reduced and the joint strength is reduced. on the other hand,
When the amount of pushing of the friction stir tool 50 becomes too small, FIG.
As shown in (1), in the joint S formed along the abutting surface F of the metal members M1 and M2, the burr b and the dent h become small, but an internal defect (gap) k occurs due to insufficient pushing. For this reason, there was a problem that the joining strength of the joining portion S was reduced.

A friction stir tool 60 as shown in FIG. 9 (C) has also been proposed in order to obtain the joint S without the burr b. This tool 60 has a stirring pin 68 hanging at the center of a bottom surface 64 of a cylindrical tool main body 62 and a peripheral groove 66 formed on the bottom surface 64 around the pin 68. When the tool 60 is moved while rotating at a high speed along the butt surface F of the metal members M1 and M2, the metal near the butt surface F which has been fluidized and softened by the stirring pin 68 once enters the circumferential groove 66. It is difficult to form burrs b on both sides of the joint S (Japanese Patent Laid-Open No. 11-1036).
No. 3).

However, in the friction stir tool 60 as well, when the pushing amount is excessive, as shown in FIG. 9D, large burrs b are formed along both sides of the surface of the joint S and the joint S A recess h is formed on the surface of. For this reason, there is also a problem that the cross-sectional area of the joint S is reduced and the joint strength is reduced. Moreover, even when such a tool 60 is used, the metal at the joint S is unlikely to be dense unless an indentation force exceeding a certain level is applied, so that an internal defect including a minute gap k is likely to occur. In order to prevent this, if the tool main body 62 is used while being pressed slightly into the metal members M1 and M2, there is a problem that the above-mentioned dent h is formed on the surface of the joint S.

[0007]

SUMMARY OF THE INVENTION The present invention solves the problems in the prior art described above, and provides a friction stir tool and a friction stir tool which can easily form a joint or a stir section in which burrs and internal defects are unlikely to occur. Another object of the present invention is to provide a method of using such as a bonding method using the same.

[0008]

According to the present invention, in order to solve the above problems, an inner metal reservoir is formed around a stirring pin and an outer metal reservoir is formed outside the stirring pin on a bottom surface of a tool body. It was made inspired by. That is, the friction stir tool of the present invention includes a column-shaped tool main body, and a stirring pin that hangs down from the bottom surface of the tool main body, and forms a ring-shaped convex portion near the periphery of the bottom surface of the tool main body. Forming a convex body that hangs down (toward the bottom surface) from the ring-shaped convex portion between the portion and the stirring pin, and an outer metal pool portion is located between the ring-shaped convex portion and the convex body. In addition, an inner metal pool portion is located on (the bottom side of) the convex body.

According to this, since the convex body of the tool main body is inserted together with the stirring pin and a pushing force is applied near the stirring pin, an internal defect occurs at the joining portion of the metal member or the stirring portion of the casting surface layer. Can be prevented. Further, the metal plastically fluidized and extruded by the stirring pin once enters the inner metal reservoir on the bottom side of the convex body, and a part thereof is further extruded and enters the outer metal reservoir. In addition, the fluidized metal is pushed out to the surface level of the metal member or the like by the ring-shaped protrusion, so that it is difficult for the metal to be pushed out from the bottom surface of the tool body to the outside, so that burrs do not occur. As a result, the metal that has entered the inner and outer metal reservoirs passes through the side of the stirring pin with the movement of the friction stir tool, and shifts to the position where the stirring pin was located immediately before solidifying. A sound joint or a stirrer in the casting surface layer is formed without internal defects such as voids, surface defects, and burrs. Therefore, it is possible to reliably obtain a sound joining portion having a required joining strength or a dense stirring portion of the casting surface layer in which fine voids near the casting surface are removed.

The column-shaped tool body includes a cylindrical shape, a regular polygonal prism (a quadrangular prism, a hexagonal prism, an octagonal prism, etc.), or a deformed polygonal prism. For this reason, the bottom surface of the tool body includes a circular shape, a regular polygon (such as a hexagon / octagon), or a deformed polygon. The stirring pin includes a form that is coaxial with the tool body and hangs down from the bottom surface thereof, and a form that hangs from a position eccentric from the center of the bottom surface. Further, the ring-shaped convex portion includes a form that presents a circular shape, a polygonal shape, or a spiral shape having about one round in a bottom view. Further, in the present specification, “just” “bottom surface”, “bottom side”, or “close to bottom surface” refers to the direction of the friction stir tool toward the tip of the stirring pin.

[0011] The present invention also includes a friction stir tool in which the ring-shaped convex portion includes an inclined surface that becomes lower from a position near a peripheral edge of the bottom surface of the tool body toward a position closer to the stirring pin. According to this, the metal that has been fluidized and extruded from the inner metal accumulation portion is easily guided to the outer metal accumulation portion by the inclined surface of the ring-shaped convex portion, and is pushed out from the bottom surface of the tool body to the outside. It becomes difficult. For this reason, burrs on the surface such as the joint can be more reliably prevented. In addition, since the metal that has entered the outer metal reservoir is spread out stepwise as the tool moves, it can also prevent surface defects such as dents in the joints and agitating parts due to poor metal spreading. It will be easier.

[0012] Further, the convex body may be a single or a plurality of spiral ridges continuous from the periphery on the bottom surface of the tool body toward the stirring pin, or a columnar body whose central portion is concave upward. Also, a friction stir tool is included in the present invention. Among these, according to the form of the convex body is a spiral ridge (including its base), presses the metal fluidized by the stirring pin, the extruded metal between the ridge and the stirring pin, or The inner metal pool located between the ridges can be securely scraped in a centripetal manner. On the other hand, according to the form of the columnar body in which the convex body is a cylindrical body and the central part is concave upward, the metal that has been fluidized and extruded by the stirring pin is pressed, and the metal is placed on the bottom surface of the convex body. Since it is easy to reliably guide to the located inner metal reservoir, internal defects at the joint and the like can be more easily prevented.
Therefore, since a certain or more indentation force is applied to the metal that has been plastically fluidized, it becomes easier to obtain a joint or a stirrer without internal defects.

In the case where the convex body has a spiral shape, the tool body and the stirring pin are pressed into the metal member or the like with its axis centered in a vertical posture (perpendicular) to the metal member to be joined. Pushed. For this reason, the bottom surface of the ring-shaped convex portion is in a state of being parallel to and substantially in contact with the surface of the metal member or the like. Therefore, it becomes easy to prevent surface defects such as dents on the surface of the joint or the like. Further, when the convex body is in the form of the columnar body, the bottom surface is formed as an inner metal pool portion in which the vicinity of the root of the stirring pin is deep and the outer periphery of the columnar body is shallow, and the bottom surface of the columnar body has a half-section. It may be a metal reservoir inside a circular or arc-shaped ring groove.

Further, the tool main body has a middle pillar having the stirring pin and the convex body on the bottom surface, and the ring-shaped convex part and the outer metal reservoir formed on the outer periphery of the middle pillar body and formed on the bottom surface. The present invention also includes a friction stir tool, which comprises an annular body having an inclined surface, and a spring pressure is applied between the annular body and the middle column in a direction toward the bottom. According to this, even if the surface of the metal member to be joined or the surface of the casting to be dense near the surface layer is accompanied by, for example, undulation, the center column of the tool main body is pushed in along the axial direction, so that the spring is formed. The annular body on the outer peripheral side can also swing and move along the surface of the metal member or the like through the pressure. In addition, since the annular body moves upward against the spring pressure, the outer metal pool formed between the convex body on the bottom surface of the middle pillar and the inclined surface of the annular body is higher than the inner metal pool. Also move to a higher position. For this reason, the metal extruded from the inner metal pool etc. surely enters the outer metal pool, so even if there is a long joint or a wide casting surface, the occurrence of burrs at the obtained joint etc. is ensured. And it can prevent continuously.

[0015] On the other hand, the method of using the friction stir tool of the present invention is such that, while rotating the friction stir tool, the bottom surface of the ring-shaped convex portion is substantially in contact with the surface of a metal member or a casting, and the tool body is used. The bottom surface and the stirring pin are moved along the butt surface or the overlapping surface of the pair of metal members, or along the surface of the casting, and the stir pin is inserted to insert the stirring surface, the overlapping surface, or the vicinity of the casting surface. By stirring the metal, friction-stir welding of the pair of metal members is performed, or minute gaps in the surface layer of the casting are removed. According to this, the metal that has been plastically fluidized and extruded by the stirring pin is allowed to once enter the inner metal reservoir on the bottom surface side of the convex body, and even if a part of the metal is further extruded, the metal remains in the outer metal reservoir. It can be surely penetrated. Also,
The metal that has entered the outer metal reservoir can also be spread over the surface of a metal member or the like. Therefore, since a sound joint or a stirrer having no internal defects such as voids and no surface defects such as burrs or dents can be formed, a sound joint having a required joint strength or fine voids near the casting surface can be removed. It is possible to reliably provide the agitated portion of the dense casting surface layer.

[0016]

Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 relates to a friction stir tool 1 according to one embodiment of the present invention. As shown in FIGS. 1 (A) and 1 (B), the friction stir tool 1 of the present invention has an SKD61.
The tool is an integrally formed product made of tool steel, such as a tool steel, and includes a cylindrical tool main body 2 and a cylindrical stirring pin 10 hanging coaxially with the main body 2 from the center of the circular bottom surface 3. A ring-shaped convex portion 4 having a circular bottom view is hung down from the periphery of the bottom surface 3 of the tool main body 2, and an inclined surface 5 is formed inside the ring-shaped convex portion 4 so as to be lower toward the stirring pin 10. Around the stirring pin 10, a columnar body (convex body) 8 which is a flat columnar shape and is located closer to the bottom surface 3 than the ring-shaped convex portion 4, that is, descends downward in FIGS. 1 (A) and 1 (B). Is formed.

As shown in FIG. 1B, the bottom surface of the columnar body 8 is recessed upward and close to the base 16 of the stirring pin 10.
(Center portion) Deeper conical inner metal reservoir 9
Is located. That is, the bottom surface of the columnar body 8 is inclined so as to be recessed upward from the vicinity of the bottom surface 3 toward the stirring pin 10 by having the inner metal reservoir 9. Further, between the inclined surface 5 of the ring-shaped convex portion 4 and the columnar body 8,
As shown in FIG. 1B, the outer metal pool 6 having a rectangular cross section is located at a higher level than the inner metal pool 9. Further, the stirring pin 10 has an arc-shaped tip surface 1.
A screw portion 14 for promoting agitation is provided between the base 2 and the base 16.

FIGS. 2A and 2B show the use state of the friction stir tool 1. FIG. The tool 1 moves at a speed of 0.05 to 2 m / min while rotating at a high speed of 100 to 1500 rpm along an abutting surface F between a pair of metal members M1 and M2 butted in the front-rear direction in FIG. To move to the right. At this time, the tool body 2 and the stirring pin 10 are several k
A pressing force (push-in force) of N to 30 kN accompanies the axial direction and, as shown in FIG. 2A, 3 to 5 ° (advance angle) on the opposite side (left side) to the moving (progressing) direction. It is inclined in the range. The bottom surface 3 of the tool main body 2 is provided with a pair of metal members M.
1 and M2, while rotating in a tilted posture in the vicinity of the surface, and moving slightly forward of the bottom surface 3 in the traveling direction, slightly above the surfaces of the metal members M1 and M2, and opposite to the traveling direction. Then, it slightly enters near the abutting surface F. The metal members M1 and M2 have
For example, a plate material having a thickness of about 10 mm made of an aluminum alloy of JIS: A6061 is used.

When the stirring pin 10 having the screw portion 14 and rotating at a high speed is inserted with a pushing force, the metal (material) of the metal members M1 and M2 near the butting surface F is inserted.
Is plastically fluidized by friction heat. Further, the metal extruded laterally or upward by the stirring pin 10 receives a downward pressing force by the columnar body 8 as shown in FIG. For this reason, internal defects such as voids can be reliably prevented in the joint S formed following the butting surface F. Further, a part of the extruded metal enters the inner metal reservoir 9 as shown by a spiral arrow near the stirring pin 10 in FIG. 2B while receiving the pushing force.

Further, a part of the metal extruded by the stirring pin 10 and the metal that has entered the above-mentioned inner metal reservoir 9 are shifted outward from the abutting surface F as shown by a spiral arrow in FIG. , And penetrates into the outer metal reservoir 6. In FIG. 2A, the metal that has entered the pool portion 6 passes through the side along the rotation direction of the stirring pin 10 and then shifts to a position where the stirring pin 10 was located immediately before. While expanding and solidifying stepwise, a joint S is formed along the abutting surface F. For this reason, the metal that has come out of the outer metal reservoir 6 does not scatter outside than the bottom surface 3 of the tool body 2. As a result, burrs along both sides of the surface of the joint S can be reliably prevented. Note that a slight depression may be formed on the surface of the joint S.

As described above, according to the friction stir tool 1, the metal fluidized and extruded by the stirring pin 10 inserted with a required pushing force in the vicinity of the butting surface F between the metal members M1 and M2. Then, it is shifted to the rear of the stirring pin 10 through the inner metal reservoir 9 and the outer metal reservoir 6 while being pressed by the columnar body 8 and solidified. Therefore, at the joint S formed along the abutting surface F, internal defects such as voids, surface defects such as dents,
And burrs do not occur. Therefore, the metal members M1 and M2 can be reliably butt-joined via the joint S having a required cross-sectional area and having sound and constant joining strength. In addition, the friction stir tool 1 is used for lap joining of metal members M1 and M2, which will be described later, and for the surface layer cm
The method can also be applied to the method for removing fine voids (surface modification) in 1.

FIG. 3 relates to a different form of friction stir tool 20 of the present invention. As shown in FIGS. 3 (A) and 3 (B), the friction stir tool 20 is also an integrally formed product made of tool steel such as SKD61, and has a cylindrical tool main body 22 and a main body extending from the center of the circular bottom surface 23. 22 and the same stirring pin 10 as described above, which is suspended coaxially. A ring-shaped convex portion 24 hangs down on the periphery of the bottom surface 23 of the tool body 22,
On the inner side, an inclined surface 25 is formed so that the position closer to the stirring pin 10 becomes lower. Further, around the stirring pin 10, the ring-shaped convex portion 2 has a spiral shape, which is about one turn or more in a bottom view.
Spiral-shaped ridges (convex bodies) that hang down closer to the bottom 23 than 4
28 are formed.

As shown in FIGS. 3 (A) and 3 (B), the spiral ridge 28 projects from the bottom surface of the flat cylindrical base 27, and an outer end 28b near the ring-shaped ridge 24. The stirrer pin 10 hangs at the same height toward the inner end 28a near the base 16 of the stirring pin 10. A spiral inner metal reservoir 29 is located between the spiral ridges 28 and between the ridge 28 and the stirring pin 10. Further, the inclined surface 25 of the ring-shaped convex portion 24 and the spiral-shaped convex stripe 28
As shown in FIGS. 3A and 3B, the outer metal pool 26 having a substantially right-angled triangular cross section is located at a higher level than the inner metal pool 29.

FIGS. 4A and 4B show how the friction stir tool 20 is used. The tool 20 rotates at a high speed of 100 to 1500 rpm along a superimposed surface F between a pair of metal members M1 and M2 made of the same aluminum alloy superimposed in the front-rear direction in FIG. .05
It is moved rightward at a moving speed of up to 2 m / min. On this occasion,
The tool body 22 and the stirring pin 10 are several kN to 30 kN.
The pressing force (pushing force) is accompanied by the axial direction. Also,
As shown in FIGS. 4 (A) and 4 (B), the tool is adjusted so that the bottom surface 23 of the tool main body 22 and more specifically the bottom surface of the ring-shaped convex portion 24 come into contact with the surface of the upper metal member M1. The axis of the main body 22 and the stirring pin 10 is in a vertical posture and is perpendicular to the superposition plane F.

When the stirring pin 10 having the screw portion 14 and rotating at a high speed is inserted, the metal (material) of the metal members M1 and M2 near the overlapping surface F is stirred by frictional heat and plastically fluidizes. . Further, the metal extruded laterally or upward by the stirring pin 10 is shown in FIG.
As shown in (1), a downward pushing force is received by the spiral ridge 28 and the bottom surface (base 27) of the inner metal reservoir 29. For this reason, it is possible to reliably prevent a situation in which an internal defect such as a void occurs in the joint portion S formed near the overlapping surface F. Further, a part of the extruded metal enters the inner metal reservoir 29 as shown by a spiral arrow near the stirring pin 10 in FIG. At this time, the spiral ridges 28 force the metal that has entered the inner metal pool portion 29 from the outer end portion 28b toward the inner end portion 28a to be forcibly moved toward the stirring pin 10. Can be.

Then, the metal extruded by the stirring pin 10 and the metal which has once entered the above-mentioned inner metal reservoir 29 are shifted upward from the overlapping surface F as shown by a spiral arrow in FIG. 4 (B). It is further extruded and enters the outer metal reservoir 26. The metal that has entered the outer pool portion 26 is spread by the ring-shaped protrusion 24 at the surface level of the metal member M1. At this time, the metal is smoothly spread by the inclined surface 25 of the ring-shaped convex portion 24, so that the surface defect of the obtained joint S can be more reliably prevented from being depressed. As a result, it is possible to reliably prevent the occurrence of burrs along both sides of the surface of the joint S and surface defects in which the surface of the joint S is depressed.

As described above, according to the friction stir tool 20, the metal which has been fluidized and extruded by the stirring pin 10 inserted with a required pressing force in the vicinity of the overlapping surface F between the metal members M1 and M2. Is shifted to the rear of the stirring pin 10 through the inner metal reservoir 29 and the outer metal reservoir 26 while being pressed by the spiral projection 28 and the bottom surface (base 27) of the inner metal reservoir 29, and solidifies. . Therefore, at the joint S formed along the overlapping surface F, internal defects such as voids, surface defects such as dents,
And burrs do not occur. Therefore, the metal members M1 and M2 can be reliably overlapped and joined via the joint S having a required cross-sectional area and having sound and constant joining strength. Note that the friction stir tool 20 is used to butt-join the metal members M1 and M2 described above and to form a casting CM described later.
Can also be applied to the method for removing fine voids in the surface layer cm1.

FIG. 5 relates to a modification of the friction stir tool 1. The friction stir tool 1a shown in the bottom view of FIG. 5 (a) and the vertical end view of FIG. 5 (A) is also made of the same tool steel as described above, and has a cylindrical tool body 2 and a central portion of the circular bottom surface 3. And the agitating pin 10 hanging down in the same manner as described above. A ring-shaped convex portion 4a having a regular octagonal bottom view is hung down from the periphery of the bottom surface 3 of the tool body 2, and an inclined surface 5a is formed inside the ring-shaped convex portion 4a. Further, a columnar body (convex body) 8 similar to the above is formed around the stirring pin 10, and an inner metal pool 9 on the bottom surface 3 side is located. The columnar body 8 has the inner metal reservoir 9, and is inclined so as to be sequentially concave upward from the vicinity of the bottom surface 3 toward the stirring pin 10. As shown in FIG. 5A, between the ring-shaped convex portion 4a and the columnar body 8, an outer metal pool portion 6 having a rectangular cross section is provided.
Is located. Incidentally, the cross section of the pool portion 6 is changed to be wide and narrow according to the inner peripheral surface of the ring-shaped convex portion 4a.

The friction stir tool 1b shown in the bottom view of FIG. 5 (b) and the vertical end view of FIG. 5 (B) also has a cylindrical tool body 2 and a similar hanging down from the center of the circular bottom 3 as described above. And a stirring pin 10 to be integrated. At the periphery of the bottom surface 3 of the tool main body 2, a ring-shaped convex portion 4b having a circular bottom view and a triangular cross section hangs down, and the inside thereof forms an inclined surface 5b in which the position closer to the stirring pin 10 is lowered. In addition, the stirring pin 10
A columnar body (convex body) 8 similar to the above is formed, and an inner metal reservoir 9 is located on the bottom surface 3 side thereof.
And it is inclined so that it may be sequentially depressed upward toward the stirring pin 10. As shown in FIG. 5B, an outer metal reservoir 6b having a substantially right-angled triangular cross section is located between the ring-shaped convex portion 4b and the columnar body 8.

The friction stir tool 1c shown in the bottom view of FIG. 5 (c) and the vertical end view of FIG. 5 (C) also has a cylindrical tool body 2 and a droop from the center of the circular bottom 3 in the same manner as described above. And a stirring pin 10 to be integrated. On the periphery of the bottom surface 3 of the tool main body 2, ring-shaped projections 4c, 4c, which are circular when viewed from the bottom and which are inner and outer, hang down. 5c. Further, a columnar body (convex body) 8 similar to the above is formed around the stirring pin 10, and an inner metal pool 9 is located on the bottom surface 3 side thereof, and sequentially upwards toward the stirring pin 10. It is inclined to be recessed. In addition, the ring-shaped convex portion 4b
As shown in FIG. 5 (C), between the inner and outer
Heavy outer metal reservoirs 6, 6 are located. Note that an inclined surface 5c may be provided inside the convex portion 4c on the inner peripheral side.

In the above friction stir tools 1a to 1c,
Similarly to the friction stir tool 1, the metal members M1, M
The metal fluidized and extruded by the stirring pin 10 inserted with a required pushing force near the abutting surface F or the overlapping surface F between the two, the inner metal reservoir portion while being pressed by the columnar body 8. 9 and the outer metal reservoirs 6, 6b, as shown in FIG.
Shifts behind and solidifies. Therefore, the tool 1
In (a) to (1c), occurrence of internal defects, surface defects, and burrs at the joint S formed along the abutting surface F and the overlapping surface F can be prevented without being greatly influenced by the pressing force applied. Therefore, the metal members M1 and M2 can be securely butt-joined or overlap-joined via the joint S having a required cross-sectional area and having a sound and constant joint strength.

The friction stir tool 1b has a simple structure at the bottom surface 3 and is easy to manufacture. In addition, the friction stir tool 1c has two inner and outer ring-shaped convex portions 4c, 4c.
Accordingly, it is possible to more reliably prevent the metal that has entered the outer metal reservoirs 6 and 6 from scattering to the outside of the bottom surface 3 of the tool body 2 and becoming a burr. Furthermore, friction stir tools 1a-1
c can also be applied to a method for removing fine voids (surface modification) in the surface layer cm1 of the casting CM described later.

FIG. 6 relates to a modified form of the friction stir tool 20. The friction stir tool 20a shown in the bottom view of FIG. 6 (a) and the vertical end view of FIG. 6 (A) is made of the same tool steel as above, and has a cylindrical tool body 22 and a central portion of the circular bottom surface 23. And the agitating pin 10 hanging down in the same manner as described above. On the periphery of the bottom surface 23 of the tool body 22,
A ring-shaped convex portion 24 having a spiral shape when viewed from the bottom and approximately one turn.
a hangs down, and the inside thereof forms an inclined surface in which the position closer to the stirring pin 10 is lowered. Further, around the stirring pin 10, a spiral-shaped ridge (convex body) 28 similar to the above is protruded from the bottom surface of the flat cylindrical base 27, and between the ridge 28 and the stirring pin 10. , An inner metal pool portion 29 is located. As shown in FIG. 6A, an outer metal pool 26 having a substantially rectangular cross section is located between the ring-shaped protrusion 24a and the base 27 of the spiral ridge 28. In addition, the cross section of the outer pool portion 26 is changed to be wide and narrow according to the inner peripheral surface of the spiral ring-shaped convex portion 24a.

The friction stir tool 20b shown in the bottom view of FIG. 6 (b) and the vertical end view of FIG. 6 (B) also has a cylindrical tool body 22 and a circular bottom 23 in the same manner as described above. It has a stirring pin 10 that hangs down. Fig. 6 (b), (B)
As shown in FIG. 5, a ring-shaped convex portion 24 hangs down from the periphery of the bottom surface 23 of the tool main body 22, and an inclined surface 25 is formed inside the ring-shaped convex portion 24 so as to be lower toward the stirring pin 10. A flat cylindrical base 27 is provided around the stirring pin 10.
Projecting from the bottom surface, having a three-quarters winding and a spiral shape when viewed from the bottom surface, and having a bottom surface 2 that is smaller than the ring-shaped projection 24.
A pair of spiral ridges (convex bodies) 28c, 2 hanging down to the third side
8c are formed symmetrically about the stirring pin 10.

A pair of spiral inner metal reservoirs 29a, 29a are symmetrically located between the ridges 28c, 28c and between the ridge 28c and the stirring pin 10. Further, between the inclined surface 25 of the ring-shaped projection 24 and the base 27 of each spiral-shaped ridge 28c, as shown in FIGS. 6B and 6B, an outer metal reservoir 26 is formed as an inner metal reservoir. It is located at a higher level than the part 29.

The friction stir tool 20c shown in the bottom view of FIG. 6 (c) and the vertical end view of FIG. 6 (C) also has a cylindrical tool body 22 and a center portion of the circular bottom 23 in the same manner as described above. It has a stirring pin 10 that hangs down. Tool body 22
A ring-shaped convex portion 24 hangs down from the periphery of the bottom surface 23 of the base member 23, and an inclined surface 25 is formed inside the ring-shaped convex portion 24 so as to be lower toward the stirring pin 10. Around the stirring pin 10, a projection is provided from the bottom surface of the flat cylindrical base 27, and is formed in a spiral shape about half a turn when viewed from the bottom, and closer to the bottom surface 23 than the ring-shaped protrusion 24. Three sets of hanging spiral ridges (convex bodies)
28d are formed symmetrically about the stirring pin 10.

As shown in FIGS. 6 (c) and 6 (C), there are three spiral inner sets between the spiral ridges 28d and between the ridges 28d and the stirring pin 10. The metal reservoir 29b is located symmetrically about the stirring pin 10. Further, between the inclined surface 25 of the ring-shaped convex portion 24 and the base 27 of each spiral-shaped convex line 28d, FIG.
As shown in (C), the outer metal pool 26 is located at a higher level than the inner metal pool 29b.

Also with the above friction stir tools 20a to 20c, similarly to the friction stir tool 20, the metal members M1 and M2 are inserted with a required pushing force into the vicinity of the abutting surface F and the overlapping surface F. The metal fluidized and extruded by the stirring pin 10 is pressed into the inner metal reservoirs 29, 29a, 29b by the pushing force of one or more spiral ridges 28, 28c, 28d (including the base 27).
Move to Further, the metal is shifted to the rear of the stirring pin 10 through the outer metal reservoir 26 and solidified as shown in FIG.

In addition, the spiral ridge 28 of about one turn is provided.
The fluidized metal can be forcibly moved toward the stirring pin 10 in the inner metal reservoirs 29a and 29b by the pair of spiral ridges 28c or three sets of spiral ridges 28d. Therefore, the tools 20a to 20
Even in the case of c, internal defects such as voids, surface defects such as dents, and burrs do not occur in the joint S formed along the abutting surface F and the overlapping surface F. Therefore, the metal members M1 and M2 can be securely butt-joined or overlap-joined via the sound joints S having a required cross-sectional area and having a constant joint strength. The friction stir tools 20a to 20c can also be applied to a method for removing minute voids in the surface layer cm1 of the casting CM described later.

The friction stir tool 30 shown in the vertical sectional view of FIG. 7A is an application form of the friction stir tool 1,
A substantially cylindrical middle pillar 31 made of the same tool steel as described above.
And an annular body 32 disposed on the outer periphery of the tool body. As shown in FIG. 7A, the middle pillar 31 is
The same stirring pin 10 as described above, which has a ring-shaped flange 31b and a cylindrical cover 31c on the side surface of a cylindrical main body 31a, and has a bottom surface 33 side coaxially with the main body 31a from the center, A columnar body having an inner metal reservoir 39 which is recessed upward nearer to the pin 10 and located around the pin.
(Convex body) 38. In addition, the annular body 32 has a ring-shaped convex portion 34 hanging down from the periphery on the bottom surface 33 side, and has an inclined surface 35 which becomes lower toward the stirring pin 10 inside the annular convex portion 34. The annular body 32 and the flange 31 of the middle column body 31
7A, the coil spring 31
The spring member d presses the annular body 32 down to the position indicated by the solid line in FIG. Further, as shown in FIG.
c, a concave portion 31e that opens downward is formed, and a convex piece 32a that fits into the concave portion 31e when the annular body 32 rises against the spring pressure is formed on the outer edge of the annular body 32.
Is erected.

A friction stir tool 40 shown in a vertical sectional view of FIG. 7C is an application form of the friction stir tool 20 and is made of the same tool steel as that described above, and has a substantially cylindrical middle column 4.
1 and a tool body composed of an annular body 42 arranged on the outer periphery thereof. As shown in FIG. 7 (C), the middle pillar 41 is
On the side surface of the columnar main body 41a, there is provided a ring-shaped flange and a cylindrical cover (not shown) similar to the above, and on the bottom surface 43 side, the same stirring pin 10 as described above, which hangs coaxially with the main body 41a from the center. And one or more spiral-shaped ridges (convex bodies) 48 depending from the lower side of the base 47. A spiral inner metal pool 49 is located between the stirring pin 10 and the spiral ridge 48.

As shown in FIG. 7 (C), the annular body 42 has a ring-shaped convex portion 44 hanging down on the peripheral edge on the bottom surface 43 side, and the inside thereof has an inclined surface which becomes lower toward the stirring pin 10. 45. A coil spring (not shown) similar to the above is interposed between the annular body 42 and the flange of the middle pillar 41,
Due to the spring pressure, the annular body 42 is pushed down to the position shown by the solid line in FIG. still,
This tool 40 is also provided with a concave portion similar to the above and a convex piece (not shown) that fits into the concave portion.

FIG. 7D relates to a method for removing fine voids in the surface layer cm1 of the casting CM using the friction stir tools 30 and 40. Surface layer c in aluminum alloy casting CM
Along the surface including m1, the friction stir tools 30 and 40 are rotated and moved in the same manner as described above so as to form a meandering movement trajectory in plan view, and are formed at the marks as shown in FIG. 7 (C). The plurality of stirring units K1, K2, K3 are overlapped with each other. At this time, the annular body 32 of the friction stir tool 30 moves while rotating with the middle column body 31, but due to the repulsive force from the surface of the casting CM, one point in FIG. It rises to the position of the dashed line, and forms the outer metal pool portion 36 between itself and the middle column 31. In addition, the annular body 32 is fitted with the concave portion 31e and the convex piece 32a as it rises,
It rotates in synchronization with the middle column 31. At the same time, the annular body 32
Swings following the undulation along the surface of the casting CM.
The tool 30 is used at an angle of 3 to 5 degrees with respect to the surface of the casting CM in the direction opposite to the moving direction.

The annular body 42 of the friction stir tool 40
Also moves while rotating with the middle column 41, but the casting CM
7 against the spring pressure by the repulsive force from the surface of FIG.
(C) Ascends to the position indicated by the broken line in FIG. At the same time, the annular body 42
Swings following the undulation along the surface of the casting CM.
The tool 40 is used in a posture perpendicular to the surface of the casting CM. Thereby, the surface layer cm of the casting CM
The metal which has been fluidized and extruded by the stirring pin 10 inserted with the required pushing force into the inside 1 is given a downward pushing force by the columnar body 38 or the spiral ridge 48 and the inner metal reservoirs 39 and 49. Get into it.

The metal is formed in an outer metal pool 36 formed between the annular body 32 and the middle column 31 or an outer metal pool formed between the annular body 42 and the middle column 41. After passing through 46, as shown in FIG. 2 (A) and FIG. 4 (A), it is shifted behind the stirring pin 10 and solidified. As a result, it becomes possible to remove fine voids existing in the surface layer cm1 of the casting CM and to reform the surface layer into a dense structure.
The friction stir tools 30 and 40 are the same as those of the metal member M described above.
It can also be applied to butt joining or lap joining of 1, M2. Further, the annular bodies 32 and 42 are brought into frictional contact with the cover 31c and the like, so that
They may be rotated substantially in synchronization with the first and the first.

The present invention is not limited to the embodiments described above. For example, the stirrer pin 10 is not limited to a form hanging down coaxially from a center portion such as the bottom surface 3 of the tool main body 2, but may be a form hanging down from a position slightly eccentric from the center such as the bottom surface 3. In addition, the stirring pin 10
Is not limited to the columnar shape, and may be a regular polygonal prism having four or more square poles or a deformed polygonal prism. Alternatively, instead of the screw portion 14 on the peripheral surface of the stirring pin 10, a plurality of continuous thin grooves parallel or perpendicular to the axis of the stirring pin 10 are provided on the peripheral surface of the stirring pin 10, In addition, a plurality of ring convex pieces or scattered projections forming a concentric circle may be provided in a protruding manner. Further, the material of the metal member or the casting to be subjected to the method of the present invention is not limited to the aluminum alloy, but includes copper and copper alloy, various steel materials, stainless steel, titanium alloy and the like.

[0047]

According to the friction stir tool of the present invention described above, since the convex body is inserted together with the stirring pin, it is possible to prevent internal defects in the joint portion of the metal member and the stirring portion of the casting surface layer, and The metal plastically fluidized and extruded by the stirring pin once enters the inner metal reservoir on the bottom side of the convex body, and a part thereof is further extruded and enters the outer metal reservoir. In addition, since the fluidized metal is pushed to the surface level of the metal member or the like by the outer metal reservoir, it is difficult for the metal to be pushed out from the bottom surface of the tool body to the outside, and burrs do not occur.
In addition, the metal that has entered the inner and outer metal reservoirs moves along with the movement of the friction stir tool and moves to the position where the stirring pin was located immediately before being solidified, and is free from internal defects such as voids and burrs. Forming a stable joint or a stirring part on the surface of the casting. Therefore, it is possible to reliably obtain a sound casting portion having a required joining strength or a dense casting surface layer from which fine voids near the casting surface have been removed.

According to the friction stir tool of the second aspect, the metal that has been fluidized and extruded from the inner metal reservoir is guided to the outer metal reservoir by the inclined surface of the ring-shaped projection. It is hard to be pushed out from the bottom of the tool body to the outside, and it is possible to more reliably prevent burrs from being generated. In addition, since the metal entering the outer metal reservoir is raised and spread stepwise, surface defects at the joint can be prevented. Further, according to the friction stir tool of the third aspect, when the convex body is in the form of a spiral ridge, the fluidized metal is pressed, and the metal is centriped into the inner metal reservoir portion to be surely scraped. In addition, in the form of the columnar body in which the convex body is a cylindrical body having a concave central portion, the fluidized metal can be pressed and the metal can be easily guided to the inner metal reservoir. Therefore, since a certain or more indentation force is applied to the metal that has been plastically fluidized, it becomes easier to obtain a joint or a stirrer without internal defects.

Further, according to the friction stir tool of the fourth aspect, even if the surface of the metal member or the casting is undulating, for example, the center column of the tool is pushed in along the axial direction, so that the spring pressure is applied. Accordingly, the outer annular body can be moved while rotating along the surface of the metal member or the like. Moreover,
Since the outer metal pool formed between the middle pillar and the annular body shifts to a position higher than the inner metal pool, the metal pushed out from the inner metal pool is surely transferred to the inner metal pool. Get in. Therefore, generation of burrs and surface defects can be reliably prevented even in a long joint portion or a wide casting surface.

On the other hand, according to the method of using the friction stir tool of the present invention, the fluidized and extruded metal is caused to enter the inner metal reservoir, and even if a part of the metal is further extruded, the metal is retained in the outer metal reservoir. You can get in. Therefore, since a sound joint or a stirring part of the casting surface layer without internal defects such as voids and surface defects such as burrs and dents can be formed, a sound joint having a required joint strength or a fine void near the surface of the casting. Thus, it is possible to reliably provide a surface layer of a dense casting from which is removed.

[Brief description of the drawings]

1 (A) and 1 (B) are perspective views or vertical end views showing one embodiment of a friction stir tool of the present invention.

2A is a schematic view showing a use state of the friction stir tool of FIG. 1, and FIG. 2B is a cross-sectional view taken along a line BB in FIG.

FIGS. 3A and 3B are perspective views or vertical end views showing different types of friction stir tools.

4A is a schematic view showing a use state of the friction stir tool of FIG. 3, and FIG. 4B is a cross-sectional view taken along a line BB in FIG.

5 (a) to 5 (c) are bottom views showing respective modified forms of the friction stir tool of FIG. 1, (A) to (C) are AA lines of (a) to (c),
FIG. 6 is an end view at a viewing angle along the line BB or the line CC.

6 (a) to 6 (c) are bottom views showing respective modified forms of the friction stir tool of FIG. 3, and FIGS. 6 (A) to 6 (C) are AA in FIGS.
FIG. 4 is an end view at a viewing angle along a line, a BB line, or a CC line.

7 (A) and 7 (C) are vertical sectional views showing each application form of the friction stir tool of FIG. 1 or FIG. 3, FIG. 7 (B) is a partial perspective view of the tool of FIG. The schematic diagram which shows the vicinity of the stirring part formed in the surface layer of the casting using the tool of FIG.

8 (A) and 8 (B) are perspective views or vertical sectional views showing a conventional friction stir tool, and FIG. 8 (C) is a schematic view showing a use state thereof.

9 (A) and 9 (B) are schematic views showing the vicinity of a joint portion joined by the friction stir tool of FIG. 8, (C) is a vertical sectional view of a conventional friction stir tool having a different form, and (D). FIG. 2 is a schematic view showing the vicinity of a joint portion joined by the above.

[Explanation of symbols]

1, 1a to 1c, 20, 20a to 20c, 30, 40 Friction stir tool 2, 22 …………………………………… Tool body 3,23,33,43… ………………… Bottom surface 4,4a-4c, 24,24a, 34,44 …… Ring-shaped convex portion 5,5a-5c, 25,35,45 …………… Inclined surface 6, 6b, 26, 36, 46 ………………… Outer metal reservoir 8, 38 ……………………………………………………………………………………………………
(Convex body) 9, 29, 29a, 29b, 39, 49 ... Inner metal reservoir 10 ................................. Agitating pin 28, 28c, 28d, 48 ………………………………………………………………………………………………………………. ………………………………………………………………………………………………………… Metal member F …………………… ………………… butting / overlapping surface CM ……………………………………………………………………………………………………………………………………………………………………………………… ……………………… Surface layer

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[Procedure amendment]

[Submission date] February 9, 2001 (2001.2.9)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

FIG. 3

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Shinya Makita 1-34-1, Kambara, Kambara-cho, Anbara-gun, Shizuoka Prefecture F-term in Nippon Light Metal Co., Ltd. Group Technology Center

Claims (5)

[Claims] 1. A tool body having a columnar shape and a stirring pin hanging down from a bottom surface of the tool body, wherein a ring-shaped protrusion is formed near a peripheral edge of the bottom surface of the tool body, and the ring-shaped protrusion and the stirring pin are provided. A convex body that hangs down from the ring-shaped convex portion is formed between the ring-shaped convex portion and an outer metal pool portion is located between the ring-shaped convex portion and the convex body; A friction stir tool, wherein the pool portion is located. 2. The friction stir tool according to claim 1, wherein the ring-shaped convex portion includes an inclined surface which becomes lower from a position near a peripheral edge of the bottom surface of the tool body toward a position closer to the stirring pin. 3. The convex body is a single or plural spiral ridges continuous from the peripheral edge on the bottom surface of the tool main body toward the stirring pin, or a columnar body whose central part is concave upward. The friction stir tool according to claim 1 or 2, wherein: 4. The tool body has a middle pillar having the stirring pin and the convex body on the bottom surface, and the ring-shaped convex part and the outer metal pool part arranged on the outer periphery of the middle pillar body and on the bottom surface. 4. An annular body having an inclined surface which is formed, wherein said annular body is provided with a spring pressure in a direction closer to the bottom surface between said annular body and said middle column body. The described friction stir tool. 5. A bottom surface of a tool main body and a stirring pin are rotated while rotating the friction stir tool of claim 1 to 4 while a bottom surface of the ring-shaped convex portion substantially contacts a surface of a metal member or a casting. Abutting or overlapping surfaces of a pair of metal members, or while moving along the surface of the casting, inserting the stirring pin, the butting surface,
A method of using a friction stir tool, comprising stirring a metal near a superimposed surface or a casting surface, thereby friction stir joining the pair of metal members, or removing fine voids in a surface layer of the casting. .