JP2003225778A - Friction stirring and joining method, and friction stirring tool used for the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a friction stirring and joining method which prevents a surface layer part covering the surface of a joined part and unsuitable for joining from being mixed into the joined part, and which improves the quality, appearance, corrosion resistance, strength or the like of the joined part, and to provide a friction stirring tool. <P>SOLUTION: The joined part 32 of materials 30 and 31 to be joined has a surface skin layer 33 including an oxide film layer, a dissimilar metal layer and a paint layer and the like formed on the surface of the joined part. This joined part 32 is subjected to friction stirring and joining by rotating and moving the friction stirring tool 36 along the joined part 32. The friction stirring tool 36 comprises a columnar tool body 36A, a stirring pin 36B protruded from a bottom surface 37 of the tool body 36A, a stirring projecting bar 36C and a peeling projecting bar 36D protruded from the bottom surface 37 so as to surround the circumference of the stirring pin 36B, and peels off the surface skin layer 33 at an outer circumferential surface of the peeling projecting bar 36D. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction stir welding method and a friction stir tool used in this method, and more particularly to an object having a skin layer such as an oxide film layer, a dissimilar metal layer or a paint layer formed on the surface of the joint. The present invention relates to a friction stir welding method suitable for friction stir welding of a joining material and a friction stir tool used in this method.

[0002]

2. Description of the Related Art Aluminum material is TIG welded and MIG
When performing fusion welding by welding, etc., if an oxide film layer, a dissimilar metal layer, a paint layer, or other skin layer unsuitable for welding exists on the surface of the welded portion, blowholes may be generated in the welded portion or foreign matter may be caught. In order to reduce the joint strength and corrosion resistance, the skin layer of the weld is removed before welding. For example,
When welding the cathode plate used for zinc refining, if the Zn layer remaining on the surface evaporates due to welding heat and mixes into the weld, welding failure occurs, so remove the Zn layer on the surface by machining beforehand. There is.

Friction stir welding (Fric) for joining two metallic materials (materials to be joined) made of an aluminum alloy by solid-state welding instead of fusion welding such as TIG welding and MIG welding.
tionStir Welding) is known to be capable of joining even if the cleanliness of the surface of the material to be joined is somewhat lower than that of fusion welding. For example, it can be joined even if oil or the like is attached to the surface.

The friction stir welding method is a method of using frictional heat to butt together or superimpose the welded portions of the materials to be welded together.
A case where two materials to be joined are butt-joined will be described. In this friction stir welding method, a friction stir tool 3 made of a material that is harder and has better heat resistance than the materials to be welded 1 and 2 is rotated at a high speed, and a stirring pin 4 integrally provided at the tip of the tool 3 is provided. Friction heat is generated in the joint portion 5 by pushing in along the joint surface 6 and moving the tool 3 in the direction of arrow A along the joint surface 6. The frictional heat softens the metal M in the vicinity of the joint surface 6 of the two materials to be welded 1 to a plasticizable state, stirs and flows by the stirring action of the stirring pin 4 at high speed, and then the stirring pin 4 As the heat source is lost due to the passage of
Solid phase bonding. In this case, the friction stirring tool 3 is moved in the direction opposite to the traveling direction by an angle α (forward angle α: 3 to 5).
The metal in front of the friction agitation tool 3 is introduced into the metal reservoir of the friction agitation tool 3 by inclining it by (°), and it is possible to supply to the portion where the agitation pin 4 has passed. For this reason, the friction stir tool 3 is usually held and moved in a state in which the front edge 8 in the moving direction of the tool body 3A is positioned above the surface of the joint 5, and friction stir welds the joint 5. The friction stir tool 3 used in a state of being inclined with the forward angle α is referred to as an inclination tool.

[0005]

However, in the friction stir welding method using the conventional tilting tool 3 described above,
When there is a skin layer 7 such as alumite, paint or Zn layer on the surface of the materials to be joined 1 and 2, the skin layer 7 is the tool body 3
There is a problem in that the corrosion resistance and the joint strength are lowered because foreign matter is mixed into the joint portion 5 when it is caught in the plasticized metal M and stirred because it is peeled off by the stirring pin 4 on the lower surface 9 side of A. Therefore, in the case of friction stir welding, the skin layer 7 covering the surfaces of the materials 1 and 2 to be welded
Had to be previously removed by machining as in the case of fusion welding. For this reason, there is a problem that the number of work steps is increased by one and the work is troublesome and the manufacturing cost is increased.

The skin layer 7 which is not suitable for friction stir welding has the joining portion 5
As one of the measures to prevent the friction stir tool 3 from being entangled in the joint 5, the front end edge 8 in the moving direction of the tool is increased by increasing the pushing amount of the friction stir tool 3 into the joint 5. It is conceivable to push it into the joint portion 5. In this way, the skin layer 7 can be peeled off by the front end edge 8 of the friction stir tool 3 in the moving direction, so that it is not necessary to remove the skin layer 7 by machining as a pre-process. However, in this case, the metal cannot be taken into the metal reservoir of the friction stir tool 3 and a surface defect occurs, and the plate thickness of the joint 5 increases from T1 to T due to an increase in the pushing amount.
Since it is reduced to 2, there is a problem that the joint strength of the joint portion 5 is also reduced. For example, when the plate thickness is 6 mm, the thickness of the joint portion 5 is reduced by about 1 mm.

Recently, a friction stir tool has been developed in which the friction stir welding is performed by inserting the joint substantially perpendicularly to the joint. As shown in FIGS. 7 and 8, the friction stir tool 20 includes a tool body 20A having a columnar shape, a stirrer pin 20B integrally provided on the center of a flat bottom surface 21 of the tool body 20A, and a stirrer pin 20B. Here, it is referred to as a scroll tool by being constituted by a spiral stirrer for projection 20C integrally provided on the bottom surface 21 so as to surround the. In the scroll tool, the agitating pin 20B and the agitating ridge 20C are substantially perpendicular to the joint 5 (advancing angle α
= 0 °) and is moved along the joint surface while being rotated at a high speed to friction stir weld the joint portion 5.

According to such a scroll tool 20, since the forward angle (α) is zero, the scroll tool 2
The surface layer 7 made of, for example, Zn, which covers the surface of the joint portion 5 in front of 0, which is not suitable for joining, can be peeled off by the stirring ridge 20C. However, the tool body 20
Since the bottom surface 21 presses the skin layer 7 in front of the joint portion, a part of the skin layer 7 peeled off by the stirring protrusion 20C on the bottom surface 21 side is not pushed out to the outside of the bottom surface 21 and the scroll tool 20 is used. It is caught in the plasticized metal M as it rotates. Therefore, similar to the friction stir welding by the inclined tool 3 shown in FIGS.
Surface defects, internal defects, etc. occur on the surface, and the appearance, corrosion resistance, and joint strength of the joint 5 are reduced.

For this reason, the skin layer of the joint is peeled off at the front side in the traveling direction of the tool so as not to be mixed into the plasticized metal so that surface defects, internal defects, etc. do not occur at the joint. There is a demand for development of a friction stir welding method and a tool thereof capable of improving the appearance, corrosion resistance and joining strength of the joint.

The present invention has been made to meet the above-mentioned conventional problems and demands, and the purpose thereof is to:
Prevents a skin layer covering the surface of the joint that is not suitable for joining from entering the joint, and improves the quality, appearance, and corrosion resistance of the joint.
It is an object of the present invention to provide a friction stir welding method and a friction stir tool thereof capable of improving strength and the like.

[0011]

In order to achieve the above object, in the friction stir welding method according to the first aspect of the present invention, a skin layer such as an oxide film layer, a dissimilar metal layer or a paint layer is formed on the surface of the joint. A method of friction stir welding the welded portion by rotating and moving the friction stir tool along the welded portion of the material to be welded, wherein the friction stir tool is inserted substantially vertically into the welded portion, Friction stir welding is performed on the joint portion while peeling off the skin layer covering the surface of the joint portion on the front side in the traveling direction of the tool on the outermost peripheral surface.

In the first aspect of the present invention, since the skin layer covering the surface of the joint portion and unsuitable for joining is stripped off by the outermost peripheral surface of the friction stir tool, the stripped layer is wound into the plasticized metal. Never be

A friction stir welding method according to a second aspect of the present invention is friction stir welding along a joining portion of a material to be joined in which a surface layer such as an oxide film layer, a dissimilar metal layer or a paint layer is formed on the surface of the joining portion. A method of friction stir welding the joint by moving the tool while rotating, wherein the friction stir tool comprises a columnar tool body, a stirrer pin projecting from the bottom surface of the tool body, and a stirrer of the stirrer pin. An agitating ridge body that is provided in a spiral shape on the bottom face so as to surround the periphery, and a peeling protrusion that is provided on the outer peripheral edge portion of the bottom face and has a height lower than that of the agitating ridge body. A ridge, and the stirring pin,
The skin layer in which the agitating ridge body and the peeling ridge body are inserted substantially vertically into the joint portion, and the outer peripheral surface of the peeling ridge body covers the surface of the joint portion on the front side in the traveling direction of the tool. Is to be friction stir welded while the strip is stripped off by the stirrer strip.

In the second aspect of the present invention, since the skin layer covering the surface of the joint portion and unsuitable for joining is stripped off by the outer peripheral surface of the stripping strip, the stripped skin layer is located on the bottom side of the tool body. It does not get caught in the plasticized metal.

A friction stir welding method according to a third aspect of the present invention is friction stir welding along a joining portion of a material to be joined in which a skin layer such as an oxide film layer, a dissimilar metal layer or a paint layer is formed on the surface of the joining portion. A method of friction stir welding the joint by moving the tool while rotating, wherein the friction stir tool comprises a columnar tool body, a stirrer pin projecting from the bottom surface of the tool body, and a stirrer of the stirrer pin. A stirring protrusion provided on the bottom surface so as to surround the periphery in a spiral shape, and the stirring pin, the stirring protrusion and the lower portion of the tool body are inserted substantially vertically into the joint, Friction stir welding is performed while the outer peripheral surface of the lower end portion inserted into the joint portion of the tool main body is peeling off the skin layer covering the front surface of the joint portion in the traveling direction of the tool.

In the third aspect of the present invention, since the skin layer covering the surface of the joint portion and unsuitable for joining is stripped off by the outer peripheral surface of the lower end portion of the tool body, the stripped skin layer is located on the bottom surface side of the tool body. It does not get caught in plasticized metal.

In the friction stir welding method according to the fourth aspect of the present invention, in the second or third aspect of the invention, the pushing amount of the outermost peripheral surface of the friction stir tool into the workpiece is 0.05 to 0.5 mm. It is a thing.

In the fourth invention, the pushing amount is 0.05.
Since the thickness is up to 0.5 mm, the skin layer unsuitable for joining the oxide film layer, the dissimilar metal layer, the paint layer and the like can be reliably peeled off. When the pushing amount is 0.05 mm or less, it becomes difficult to reliably prevent the friction stir tool of the surface layer from being introduced into the metal reservoir, and mixing into the joint portion is likely to occur. If the pushing amount is 0.5 mm or more, the occurrence of burrs increases, and the moving load of the friction stir tool increases, which makes joining difficult.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail based on the embodiments shown in the drawings. FIG. 1 is a plan view showing a friction stir welding method according to the first invention, and FIG. 2 is a sectional view showing a use state of a friction stir tool. In these figures,
Numerals 30 and 31 are materials to be joined which are formed in a rectangular plate shape by extruded profile of aluminum alloy, one end faces in the longitudinal direction thereof are butted against each other, and the butted side edges and the vicinity thereof are friction stir welding. And a butt surface forms a joint surface 32A. In addition, the surface of the materials to be joined 30, 31 has a thickness of 0.1 mm.
A Zn layer (skin layer) 33 of a certain degree is formed. on the other hand,
A backing 3 made of copper is provided on the back side of the materials 30 and 31 to be joined.
4 are in close contact along the joint 32.

A friction stir tool 36 used for friction stir welding the joint surfaces 32A of the materials 30 and 31 to be welded.
Is made of a metal having a higher melting point than the materials to be joined 30, 31 such as tool steel, and has a cylindrical tool body 36A and an agitation integrally formed at the center of the bottom surface 37 of the tool body 36A. The pin 36B and the bottom 37
And a spiral stirring projection 36C that surrounds the circumference of the stirring pin 36B and is centered toward the stirring pin 36B, and a stripping projection that is integrally projected on the outer periphery of the bottom surface 37. It is composed of a body 36D. The tool main body 36A is not limited to a cylindrical shape, and includes a polygonal pillar such as a square pillar and a hexagonal pillar. The bottom surface 37 of the tool body 36A is formed into a flat surface. The stirring pin 36B has a length shorter than the plate thickness of the materials to be joined 30 and 31, and a male screw 38 is formed on the outer periphery thereof to enhance the stirring effect. The stirring pin 36B is
The tool body 36A is not limited to the one whose axis line is substantially the same, and the tool body 36A may be slightly eccentric. The stirring projection 36C is formed lower than the stirring pin 36B. The peeling strips 36D are formed lower than the stirring strips 36C.

In order to perform friction stir welding on the joint surfaces 32A of the materials 30 and 31 to be welded using the friction stir tool 36, the friction stir tool 36 is driven by a motor to 500-10.
Stirring pin 3 while rotating at a rotation speed of about 000 rpm
6B is positioned on the joint surface 32A and pressed against the surface of the joint portion 32, and the surface portion of the joint portion 32 pressed by the stirring pin 36B of the joint portion 32 and its vicinity are heated and plasticized by frictional heat, and the stirring pin 36B, for stirring. Ridge 36C
Then, the strip projections 36D are gradually pushed into the joint portion 32. The amount (pushing amount) in which the peeling protrusion 36D is pushed into the surface of the joining portion 32 is an amount by which the Zn layer 33 can be reliably peeled off. If the pushing amount is made larger than necessary, the thickness of the material to be joined is increased. Is undesirably thin, and friction stir welding may not be performed smoothly. Further, the friction stir tool 36 is pushed substantially perpendicularly to the surface of the joint 32 so that the entire bottom surface 37 uniformly presses the surface of the joint 32.

When the stirring pin 36B, the stirring ridge 36C and the peeling ridge 36D are pushed into the joint portion 32 by a predetermined amount, the friction stir tool 36 is brought into contact with the joint surface 32A in this state.
The joint portion 32 is friction stir welded by moving the joint portion 32 in the direction of the arrow A at a feed speed (welding speed) of about 8.5 to 3 m / min. That is, when the friction stir tool 36 is moved along the joint surface 32A while rotating at a high speed, the joint surface 32A and its vicinity are plasticized by being heated by the stirring pin 36B and the stirring ridge 36C. Fluidize horizontally and vertically. Then, the fluidized metal M loses the heating source and is cooled and solidified by the passage of the stirring pin 36B.

When the friction stir tool 36 is moved in the direction of arrow A, the strip projection ridge 36D is pushed into the joint 32, so that the Zn layer 33 on the front side of the tool is stripped off by the outer peripheral surface. The outer peripheral surface of the strip projection strip 36D forms the outermost peripheral surface of the friction stir tool 36 together with the outer peripheral surface of the tool body 36A. Since the bottom surface 37 of the tool main body 36A is located inside the peeling protrusion 36D, the stripped Zn layer 33 passes under the peeling protrusion 36D and enters the lower side of the bottom surface 37. It does not occur and does not mix with the plasticized metal M. Therefore, the joint 3
2 appearance, corrosion resistance and joint strength can be increased.

Further, since the protruding dimension of the stripping strip 36D is shorter than the projecting dimension of the stirring strip 36C, the stirring strip 36C is located rearward of the center of the friction stir tool 36 in the traveling direction. The plasticized metal M extruded from the inside to the outside rises to the height of the lower surface of the strip projection 36D. In other words, the lower surface of the strip projection strip 36D defines the thickness T of the joint 32 after friction stir welding. Therefore, the thickness of the joint portion 32 is not unnecessarily removed beyond the thickness of the Zn layer 33, and the reduction in strength of the joint portion 32 of the material to be joined can be reduced.

FIG. 3 is a plan view showing a friction stir welding method according to the second invention, and FIG. 4 is a sectional view showing a state of using the friction stir tool. In these figures, the joined material 3 formed in a rectangular plate shape by an extruded profile of aluminum alloy 3
Nos. 0 and 31 form a joint 32 in which one end face in the longitudinal direction thereof is abutted against each other to frictionally stir the abutment side edge and the vicinity thereof, and the abutment face forms a joint surface 32A. . A Zn layer 33 having a thickness of about 0.1 mm is formed on the surfaces of the materials to be joined 30 and 31. On the other hand, a backing 34 made of copper is closely attached to the back surfaces of the materials to be joined 30 and 31 along the joining portion 32.

A friction stir tool 40 used to friction stir weld the joint surfaces 32A of the materials 30 and 31 to be welded.
Is a conventional scroll tool 2 shown in FIGS. 7 and 8.
By being formed in the same shape as 0, a cylindrical tool body 40A, a stirring pin 40B integrally provided in the center of the bottom surface 41 of the tool body 40A, and a stirring pin 40B on the bottom surface 41 of the stirring pin 40B. It is composed of a stirring ridge 40C that is integrally provided in a spiral shape so as to surround the periphery. The bottom surface 41 of the tool body 40A is formed into a flat surface. The stirring pin 40B has a length substantially equal to the plate thickness of the materials to be joined 30 and 31, and a male screw 42 is formed on the outer circumference. The stirring ridge 40C is the stirring pin 40B.
It is formed lower.

In order to friction stir weld the joint surfaces 32A of the materials to be welded 30 and 31 using the friction stir tool 40, the friction stir tool 40 is driven by a motor to 500 to 10
Stirring pin 4 while rotating at a rotation speed of about 000 rpm
0B is positioned on the joint surface 32A and pressed against the surface of the joint 32, and the stirring pin 40B of the joint 32 is heated by frictional heat.
The surface portion pressed by and the vicinity thereof are heated and plasticized, and the stirring pin 40B and the stirring protrusion 40 are used.
C is gradually pushed into the joint 32. Tool body 40A
The amount by which is pushed into the surface of the joint 32 (pushing amount) is Z
If the pushing amount is increased more than necessary with the amount capable of reliably peeling off the n layer 33, the thickness of the material to be welded becomes thinner than necessary, and friction stir welding may not be performed smoothly, which is preferable. Absent. Also, friction stir tool 4
0 is pressed substantially perpendicularly to the surface of the joint 32 so that the entire surface of the bottom surface 41 uniformly presses the surface of the joint 32.

When the stirring pin 40B and the stirring ridge 40C are pushed into the joint 32 by a predetermined amount, the friction stirrer tool 40 is moved along the joint surface 32A in the direction of arrow A in this state.
By moving at a welding speed of about 5 to 3 m / min,
The joining portion 32 is friction stir welded. That is, when the friction stirring tool 40 is moved along the joint surface 32A while being rotated at a high speed, the joint surface 32A and the vicinity thereof are stirred by the stirring pin 4
It is plasticized by being heated by 0B and the stirrer 40C and fluidized in the horizontal and vertical directions.
Then, the fluidized metal M loses the heating source and is cooled and solidified by the passage of the stirring pin 40B.

When the friction stir tool 40 is moved in the direction of arrow A, the lower end portion of the tool body 40A is pushed into the joint portion 32, so the Zn layer 33 on the front side of the tool is stripped off by the outer peripheral surface of the lower end portion. That is, according to the second aspect of the invention, the skin layer 33 is stripped off from the outer peripheral surface of the lower end portion of the tool body 40A, which is the outermost peripheral surface. Therefore, in this respect, the conventional scroll tool 20 shown in FIGS. 7 and 8 is used. Is different from the friction stir welding method. The Zn layer 33 peeled off by the outer peripheral surface of the lower end portion of the tool body 40A enters between the bottom surface 41 and the surface of the joint portion 32 because the bottom surface 41 of the tool body 40A presses the surface of the joint portion 32. It does not occur and does not mix with the plasticized metal M. Therefore, as in the case of the first embodiment described above, the Z peeled off on the surface of the joint portion 32 that is friction stir welded.
The n layer 33 is not mixed, and good and reliable bonding can be performed, and the appearance, corrosion resistance, and bonding strength of the bonding portion 32 can be increased.

[0030]

Example 1 As a material to be joined, a material composed of a cathode plate used for zinc refining was cut out and abutted on each other, and the abutted joints were friction stir welded. The material is JIS A107 with a plate thickness of 6 mm, which has a high Al purity and a low Si content.
It is 0-O. The friction stir welding was performed using the scroll tool 36 with the strip for protrusions shown in FIG. 2, the conventional tilt tool 3 shown in FIG. 6, and the conventional scroll tool 20 shown in FIG. 7. The scroll tool 36 shown in FIG. 2 pushes the peeling strips 36D into the joint portions 32 of the members to be joined 30, 31 by an amount capable of reliably stripping the Zn layer 33, and performs friction stir welding. The tilting tool 3 moves forward in the direction opposite to the advancing direction α (= 3 to 5).
The metal in front of the advancing direction is introduced into the metal pool D of the friction stir tool 3 by inclining the stir pin 4
Friction stir welding is performed while supplying to the portion where is passed. The scroll tool 20 shown in FIG. 7 pushes the spiral stirrer 20C for stirring at a forward angle α = 0 ° below the skin layer 7 to perform friction stir welding. The rotation speed and the welding speed of each tool are 900 rpm and 300 mm / min, respectively. The results are shown in Table 1.

[0031]

[Table 1]

As is clear from Table 1, when the scroll tool 36 with peeling projections is used, the quality of the joint is better and surface defects and internal defects are better than those of the conventional tilt tool 3 and scroll tool 20. Never happens,
The appearance, corrosion resistance and strength can be improved. Further, since the reduction in the plate thickness of the joint can be suppressed, the joint having the required strength can be obtained. In addition, the standard scroll tool of the third stage in Table 1 has the outermost periphery of the tool body that does not contact the surface of the material to be welded, and the fourth conventional scroll tool has the outermost periphery of the tool body that has the outermost periphery of the tool body to be welded. It is buried from the surface of.

[0033]

Example 2 As materials to be joined, materials made of JIS A6063-T5 having a plate thickness of 6 mm and having an oxide film layer of 9 μm formed on the surface were butted against each other, and the butted joints were friction stir welded. In the friction stir welding, the tool 36 of the present invention shown in FIG.
Friction stir welding was performed using the conventional tilt tool 3 shown in FIGS. 5 and 6 and the conventional scroll tool 20 shown in FIGS. 7 and 8 in the same manner as in Example 1 described above. The tool rotation speed and welding speed are 900 rpm and 3 respectively.
It is 00 mm / min. The results are shown in Table 2.

[0034]

[Table 2]

As can be seen from Table 2, when the scroll tool 36 with peeling strips is used, the quality of the joint is higher than that of the conventional tilt tool 3 and scroll tool 20 as in the first embodiment. It is good and does not cause surface defects or internal defects, and can improve appearance, corrosion resistance and strength. Further, since the reduction in the plate thickness of the joint can be suppressed, the joint having the required strength can be obtained.

In the above-described embodiment, the case where the skin layer of the joint portion is the Zn layer and the oxide film layer has been described, but the present invention is not limited to this, and an oxide film is formed by alumite treatment. A coating film may be formed on it, and any metal member may be used as long as it has a skin layer unsuitable for friction stir welding. Further, in the first embodiment, the friction stir tool 36
The example in which the stirring projection 36C projectingly provided on the bottom surface 37 of the tool main body 36A is composed of two large and small ring-shaped projections formed of concentric circles is shown, but the invention is not limited to this. It may be a body or the spiral projecting body 20C shown in FIG.

[0037]

As described above, according to the friction stir welding method and the friction stir tool used in the method according to the present invention, an oxide film layer, a dissimilar metal layer, which is present on the surface of the joint portion and is not suitable for friction stir welding, Since the skin layer such as the paint layer can be stripped by the outermost peripheral surface on the front side in the moving direction of the tool, the stripped skin layer is not mixed in the plasticized metal. Therefore, the appearance and corrosion resistance and strength of the joint can be improved without causing defects on the surface or inside of the joint. Further, the pushing amount of the outermost peripheral surface of the friction stir tool into the material to be welded is 0.05 to 0.5.
Since the thickness is set to mm, friction stir welding can be performed reliably, and the amount of reduction in the plate thickness of the materials to be welded is small, and a welded portion having the required strength can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view showing a friction stir welding method according to a first invention.

FIG. 2 is a sectional view showing a usage state of the friction stir tool.

FIG. 3 is a plan view showing a friction stir welding method according to a second invention.

FIG. 4 is a cross-sectional view showing a usage state of the friction stir tool.

FIG. 5 is a perspective view showing a state of friction stir welding using a conventional tilting tool.

FIG. 6 is a cross-sectional view showing a usage state of the tilt tool.

FIG. 7 is a perspective view showing a state of friction stir welding by a conventional scroll tool.

FIG. 8 is a cross-sectional view showing a usage state of a scroll tool.

[Explanation of symbols]

1, 2 ... Joining material, 3 ... Inclined tool, 5 ... Joined part, 6 ... Joined surface, 7 ... Zn layer, 20 ... Scroll tool, 30, 3
1 ... Bonding material, 32 ... Bonding part, 32A ... Bonding surface, 34 ... Backing, 36 ... Friction stirring tool, 36A ... Tool body, 3
6B ... Stirring pin, 36C ... Stirring ridge body, 36D ... Peeling ridge body, 37 ... Bottom surface, 40 ... Friction stirring tool, 40A
... Tool body, 40B ... Stirring pin, 40C ... Stirring ridge body, 41 ... Bottom surface.

Continued front page    (72) Inventor Motoji Hotta             1-34-1 Kambara, Kambara Town, Anbara District, Shizuoka Prefecture Japan             Light Metal Co., Ltd. Group Technology Center F-term (reference) 4E067 AA05 BG00 CA01 CA04 DC07

Claims (4)

[Claims] 1. A friction stir tool is rotated and moved along the joint portion of a material to be joined in which a skin layer such as an oxide film layer, a dissimilar metal layer, or a paint layer is formed on the surface of the joint portion. A method of friction stir welding a joint, wherein the friction stir tool is inserted substantially perpendicular to the joint,
A friction stir welding method wherein the joint portion is friction stir welded while peeling off the skin layer covering the front surface of the joint portion in the traveling direction of the tool at the outermost peripheral surface. 2. A friction stir tool is rotated and moved along the joint portion of a material to be joined in which a skin layer such as an oxide film layer, a dissimilar metal layer, and a paint layer is formed on the surface of the joint portion. A method of friction stir welding of a welding part, wherein the friction stir tool comprises a columnar tool body, a stirring pin protruding from a bottom surface of the tool body, and a spiral shape on the bottom surface so as to surround the stirring pin. The stirring pin and the stirring pin, which has a height lower than that of the stirring protrusion and is provided on the outer peripheral edge of the bottom surface. , The skin in which the stirring ridges and the peeling ridges are inserted substantially vertically into the joint, and the outer peripheral surface of the peeling ridge covers the front surface of the joint in the advancing direction of the tool. Special feature is friction stir welding of the joint while peeling off the layers. Friction stir welding method according to. 3. The friction stir tool is rotated and moved along the joint portion of the material to be joined in which a skin layer such as an oxide film layer, a dissimilar metal layer or a paint layer is formed on the surface of the joint portion. A method of friction stir welding of a welding part, wherein the friction stir tool comprises a columnar tool body, a stirring pin protruding from a bottom surface of the tool body, and a spiral shape on the bottom surface so as to surround the stirring pin. The stirring pin, the stirring protrusion, and the stirring protrusion and the lower portion of the tool main body are inserted substantially vertically into the joint, and are inserted into the joint of the tool main body. The friction stir welding method, wherein the joint portion is friction stir welded while stripping off the skin layer covering the front surface of the joint portion in the traveling direction of the tool with the outer peripheral surface of the lower end portion. 4. The friction stir welding method according to claim 1, 2, or 3, wherein the amount of pushing of the outermost peripheral surface of the friction stir tool into the material to be welded is 0.
The friction stir welding method is characterized in that it is from 05 to 0.5 mm.