JP2003181653A - Method for friction stir welding of material having decorative surface, structure produced by the method, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for friction stir welding of materials having decorative surfaces with good appearance capable of keeping the welding strength enough. <P>SOLUTION: The first sheet material S1 and the second sheet material S2 are butt welded and a rotation tool 1 is inserted into a butt part T from decorative surfaces S1a and S2a and friction stir welded, a backing metal 4 is arranged to the decorative surfaces S1a and S2a, a rotation tool 3 is inserted into the butt part T from nondecorative surfaces S1b and S2b and friction stir welded to practically flatten the decorative surfaces S1a and S2a of the butt part T. Preferably, after friction stir welding from the decorative surfaces S1a and S2a, flash Ba is cut before friction stir welding from the nondecorative surfaces S1b and S2b. The backing metal 4 is a material having lower heat conductivity than that of sheets S1 and S2, and the rotation tool 3 is leaned backward in the advance direction preferably. <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 decorative surface (a surface which is used as an outer surface of a product and can be finally visually recognized).
The present invention relates to a method of friction stir welding members having plate materials constituting the above. The present invention also relates to a method for manufacturing a structure using the method and a structure manufactured by the method.

[0002]

2. Description of the Related Art Butt plates having a decorative surface are butted against each other,
As a conventional technique for friction stir welding the butt portion, there is one disclosed in Japanese Patent No. 3152420. This is because the first plate material and the second plate material are placed in abutment with each other, the rotary tool is inserted from only one surface of both plate materials, and the abutting portions are friction stir welded, and the other surface of both plate materials is abutted. This is a method of applying makeup. In friction stir welding, generally, dents and burrs due to the pressing of the shoulder portion of the rotary tool are inevitably formed on the surface of the plate material on the side where the rotary tool is inserted, but according to the above method, the rotary tool is inserted. Since the surface of the plate material on the side is used as the non-decorative surface (the surface that is the back surface of the decorative surface and is not finally visible from the outside), the surface of the plate material on which the rotary tool is not inserted is used as the decorative surface. Can improve the appearance of the product.

[0003]

However, in the above method, the abutting portion may remain unbonded on the surface side (cosmetic surface side) where the rotary tool is not inserted.
Therefore, the butt line of both plate materials appears as a streak on the decorative surface, and the appearance of the decorative surface deteriorates. In addition, since the unbonded portion remains, sufficient bonding strength between the plate materials cannot be obtained.

In view of such circumstances, the present invention provides a friction stir welding method for a member having a decorative surface (hereinafter, simply referred to as "friction stir welding method"), which has a good appearance and a sufficient bonding strength. ) Etc. are proposed.

[0005]

The invention according to claim 1 is
A first member having a plate material forming a decorative surface and a second member having a plate material forming a decorative surface are abutted with each other at their ends, and the decorative surface side of the plate material is rotated to the abutting portion. After inserting the tool and friction stir welding, place the backing on the decorative surface side of the plate material, and insert the rotating tool from the non-cosmetic surface side, which is the back surface of the decorative surface side of the plate material, into the butt section. The friction stir welding method for a member having a decorative surface is characterized in that the decorative surface side of the butted portion of the plate material is substantially flattened by friction stir welding.

In this friction stir welding method, the abutting portion is friction stir welded not only from the non-decorative surface side but also from the decorative surface side, so that the decorative surface side of the abutting portion is also completely joined. Therefore, no streak-shaped butt line is left on the decorative surface side of the butt portion, and sufficient joining strength can be obtained. Also, since the friction stir welding is performed from the non-decorative surface side after the friction stir welding from the decorative surface side, the metal around the recess of the butt portion caused by the friction stir welding from the decorative surface side is not rubbed from the non-cosmetic surface side. The depressions can be filled by raising the temperature at the time of stir welding to stir and fluidize and press with a rotating tool. Therefore, the decorative surface side surface of the abutting portion can be corrected to be substantially flat so that the cosmetic surface has a good appearance.

According to a second aspect of the present invention, in the friction stir welding method according to the first aspect, after the friction stir welding from the decorative surface side and before the friction stir welding from the non-cosmetic surface side, the decorative surface of the abutting portion is formed. The feature is that the burr generated on the side is removed.

[0008] In such a friction stir welding method, before the friction stir welding from the non-decorative surface side, the burrs produced by the friction stir welding from the decorative surface side are cut off, so that the friction stir welding from the non-cosmetic surface side is performed. It is possible to prevent the burr generated on the decorative surface side from remaining in a buried state and enhance the effect of correcting the dent on the decorative surface side.

According to a third aspect of the present invention, in the friction stir welding method according to the first or second aspect, the backing is made of a material having a lower thermal conductivity than both plate materials.

In this friction stir welding method, a backing made of a material having a lower thermal conductivity than both plate materials is arranged on the decorative surface side, and friction stir welding is performed from the non-decorative surface side. It is possible to prevent a local temperature drop at the backing contact portion during stir welding. Therefore, it is possible to enhance the effect of correcting the dent on the decorative surface side by friction stir welding from the non-cosmetic surface side, and to increase the moving speed of the rotary tool in the direction along the butt line for efficient welding. it can.

According to a fourth aspect of the present invention, in the friction stir welding method according to any one of the first to third aspects, the rotating tool for performing the friction stir welding from the non-decorative surface side has a moving direction. It is characterized by tilting backward so as to be oriented.

In such a friction stir welding method, the rotary tool for friction stir welding is tilted rearward from the non-decorative surface side so as to be oriented in the traveling direction, so that the rear portion of the shoulder portion of the rotary tool in the welding direction is not contacted. Since it is strongly pressed against the decorative surface, it is possible to enhance the effect of correcting the dent on the decorative surface side by friction stir welding from the non-cosmetic surface side, and also to prevent defects such as cavities on the decorative surface side of the butted part. You can

The invention according to claim 5 is a method of manufacturing a structure by the friction stir welding method according to any one of claims 1 to 4, and the invention according to claim 6 is A method of manufacturing a vehicle body structure by the friction stir welding method according to any one of claims 4 to 4.

According to the method for manufacturing a structure or vehicle structure, it is possible to efficiently manufacture a structure or vehicle structure that is good in appearance and has a high bonding strength between the plate materials at low cost.

The invention according to claim 7 is the structure manufactured by the friction stir welding method according to any one of claims 1 to 4, and the invention according to claim 8 is the structure according to claim 1. A vehicle structure manufactured by the friction stir welding method according to claim 4.

Such a structure or vehicle structure has a good appearance, has a high joint strength between the plate materials, and can be efficiently manufactured at a low cost.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the description, the same elements will be denoted by the same reference symbols, without redundant description.

FIG. 1 is a procedure explanatory view showing an embodiment of a friction stir welding method according to the present invention, and FIG. 2 is a procedure explanatory view following FIG. In this friction stir welding method, first, referring to FIG.
As shown in (a), the end of the plate material S1 which is the first member and the end of the plate material S2 which is the second member are butted against each other,
The rotary tool 1 is inserted into the abutting portion T from the decorative surfaces S1a and S2a of the two plate materials S1 and S2, and friction stir welding is performed.

Here, each of the plate materials S1 and S2 is made of an aluminum alloy and has a decorative surface S1a or S2a.
With the non-decorative surface S1b, S2b facing down, the backing 2
Fixed on. The rotary tool 1 includes a tool body 1a having a large diameter and a stirring pin 1b having a small diameter that coaxially protrudes from the tip surface of the tool body 1a.
A shoulder portion 1c is formed around the tip surface of the.
Then, from the side of the decorative surfaces S1a, S2a of the plate materials S1, S2, the stirring pin 1b of the rotary tool 1 which rotates at high speed around the central axis is inserted into the abutting portion T, and the shoulder portion 1c is slightly attached to the decorative surfaces S1a, S2a. In the pressed state,
By moving the rotary tool 1 in the direction orthogonal to the plane of the drawing along the butt line of the plate materials S1 and S2,
The abutting portion T is friction stir welded from the side of the two decorative surfaces S1a and S2a. Therefore, the decorative surfaces S1a and S2a of the abutting portion T of the plate materials S1 and S2 are completely joined, and the abutting line does not occur. The length of the stirring pin 1b may be at least enough to join at least the decorative surfaces S1a and S2a of the plate materials S1 and S2.

At this time, as shown in FIG. 3 (a), the rotary tool 1 is tilted backward by θ (for example, about 3 °) so as to direct the traveling direction. That is, the rotary tool 1 is moved along the abutting portion T in a state where the central axis CL of the rotary tool 1 is tilted backward about 3 ° with respect to the orthogonal axis P of the decorative surfaces S1a and S2a of the plate materials S1 and S2. By doing so, the rear portion of the shoulder portion 1c of the rotary tool 1 is strongly pressed against the decorative surfaces S1a and S2a, and the metal of the plate materials S1 and S2 that stirs and flows is appropriately pressed, so that the decorative surface S1a of the abutting portion T is pressed. , S2a side is less likely to cause defects such as cavities.

FIG. 1B shows a state after the rotary tool 1 is inserted into the abutting portion T from the side of the decorative surfaces S1a, S2a and friction stir welding is performed in this way. Reference numeral Ka in FIG.
This is a friction stirrer in which the metal of the plate materials S1 and S2 is frictionally stirred by the rotary tool 1. The friction stirrer Ka is formed in a region around the stirring pin 1b and the shoulder 1c of the rotary tool 1. Further, on the decorative surfaces S1a, S2a side of the abutting portion T of the plate materials S1, S2, a dent Ha resulting from the pressing of the shoulder portion 1c of the rotary tool 1 is inevitably generated,
Burrs Ba and Ba are formed on both sides of the depression Ha. The non-decorative surfaces S1b and S2b of the abutting portion T are left unbonded.

Subsequently, the decorative surfaces S1a of the plate materials S1 and S2,
The burrs Ba and Ba generated on the S2a side are cut off. Excision
An appropriate tool such as an end mill, a ball end mill, or a stainless brush is used to perform processing so that the depression Ha has a gentle groove shape as shown in FIG. 1 (c).

Next, as shown in FIG. 2A, the decorative surface S
The plate materials S1 and S2 are arranged upside down so that the lamina S1a and S2a face down and the non-decorative surfaces S1b and S2b face up, and fixed on the backing 4. Then, the butting portion T is friction stir welded by the rotary tool 3 from the non-decorative surfaces S1b, S2b side.

At this time, the diameter w ₂ of the stirring pin 3b of the rotary tool 3 is larger than 0.5 times the diameter w ₁ of the shoulder portion 1c of the rotary tool 1 (w ₂ > 0.5w ₁ ). .
At this time, the friction stirrer Ka frictionally stirred by the rotary tool 1 is substantially included in the frictional stirrer Kb frictionally stirred by the rotary tool 3. As a result, the non-cosmetic surface S1
b, S2b side, when the butt joint T is friction stir welded by the rotary tool 3, by the friction stir action of the metal by the stirring pin 3b and the shoulder portion 3c and the pressing action on the non-decorative surfaces S1b, S2b by the shoulder portion 3c. The metal of the abutting portion T is sufficiently agitated and fluidized, the recesses Ha are filled, and the decorative surfaces S1a and S2a are substantially flattened. In addition,
When the abutting portion T is friction stir welded from the non-decorative surface S1b, S2b side, the stirring pin 3b of the rotary tool 3 is particularly close to the recess Ha, so that the diameter w ₂ of the stirring pin 3b of the rotary tool 3 is set to the rotary tool 1's. If the diameter is larger than the diameter w ₁ of the shoulder portion 1c (w ₂ > w ₁ ), the stirring flow of the metal is further promoted, and the effect of correcting the depression Ha is enhanced.

The correction effect of the depression Ha is also affected by the thermal conductivity of the backing 4. For example, a material having a thermal conductivity higher than the thermal conductivity of the plate materials S1 and S2 (thermal conductivity of aluminum at 20 ° C .: 0.31 to 0.52 (cal / ° C. · cm · sec)) (for example, heat Conductivity about 0.9
When a backing 4 made of copper (3) is used, frictional heat at the time of friction stir welding by the rotary tool 3 easily escapes via the backing 4, so the moving speed of the rotary tool 3 in the direction along the butt portion T is high. Is large, the stirring flow of the metal at the abutting portion T becomes insufficient. Therefore, in this case, it is necessary to make the moving speed of the rotary tool 3 in the direction along the abutting portion T relatively low. On the other hand, when the backing 4 made of a material having a thermal conductivity smaller than that of the plate materials S1 and S2 (for example, iron having a thermal conductivity of 0.04 to 0.17) is used, friction stir welding by the rotary tool 3 is performed. Since the frictional heat at that time is less likely to escape via the backing 4, the metal around the depression Ha is kept at a high temperature for a relatively long time. Therefore, even if the moving speed of the rotary tool 3 in the direction along the abutting portion T is high, the metal of the abutting portion T is sufficiently agitated and fluidized, and the effect of correcting the depression Ha is enhanced. The friction stir welding can be efficiently performed at high speed by increasing the moving speed in the direction along the butt portion T.

Further, as shown in FIG. 3B, the rotary tool 3 is tilted backward by θ (for example, about 3 °) so as to direct the traveling direction. That is, the central axis C of the rotary tool 3
In a state where L is tilted rearward by about 3 ° with respect to the orthogonal axis P of the non-decorative surfaces S1b and S2b of the plate materials S1 and S2, the rotary tool 3
Is moved along the abutting portion T. If you do this,
The rear portion of the shoulder portion 3c of the rotating tool 3 is a non-decorative surface S
Plate material S that is strongly pressed against 1b and S2b and stirs and flows
The metals 1 and S2 are appropriately pressed, and defects such as cavities are less likely to occur on the non-decorative surfaces S1b and S2b of the abutting portion T.

As described above, the non-decorative surfaces S1b and S2b
FIG. 2B shows a state after the rotary tool 3 is inserted into the butt portion T from the side and friction stir welding is performed. As shown in the figure, the recess Ha is filled by friction stir welding from the non-decorative surfaces S1b, S2b side, and the decorative surfaces S1a, S2a are substantially flattened. In addition, the decorative surface S1a, S2a does not have a conventional streak-shaped butt line,
The appearance is beautiful and the decorative surfaces S1a and S2 of the abutting portion T are
Since the a side is also completely joined, the joining strength is also high. Therefore, it is preferable to use the decorative surfaces S1a and S2a so as to be arranged toward the outer surfaces of various structures. In addition,
On the non-decorative surface S1b, S2b side of the abutting portion T, a depression Hb and burrs Bb, Bb are formed due to the pressing of the shoulder portion 3c of the rotary tool 3, but the non-decorative surface is not visible from the outside. There is no problem with using.

The burr B as shown in FIG.
When the cutting process of a and Ba is omitted, the metal of the burr Ba and Ba which is left without being removed is the non-decorative surface S1.
b and S2b do not stir and flow at the time of friction stir welding, and due to the pressing action of the shoulder portion 3c of the rotary tool 3 at the time of friction stir welding from the non-decorative surfaces S1b and S2b, as shown in FIG. A groove-shaped defect portion M in which Ba is embedded in the decorative surfaces S1a and S2a is formed, which may not be suitable for use as a product.

The friction stir welding method as described above is
It can be applied to various products. For example, the railcar structure shown in FIG. 5 has plate materials S3 and S4 made of aluminum alloy,
S5 and S6, and S7 and S8 are manufactured by being bonded by the friction stir welding method of the present invention. According to the friction stir welding method of the present invention, it is possible to efficiently manufacture a vehicle body structure that looks good and has a high joint strength between plate materials at low cost. Of course, the friction stir welding method of the present invention can be applied not only to the vehicle body structure but also to any other structure body.

In the above description, the first member and the second member to be friction stir welded are both entirely plate-shaped, but the present invention is not limited to this. . The first member and the second member according to the present invention may be those in which at least the portion to which friction stir welding is applied is a plate member that constitutes a decorative surface.

For example, in the example shown in FIG. 6, the first member S9 is a double-skin structure panel having a plate material S9 'forming a decorative surface, and the second member S10 is a plate material forming a decorative surface. It is a double skin structure panel having S10 '. The plate material S9 ″ facing the plate material S9 ′ in the first member S9 and the plate material S10 ″ facing the plate material S10 ′ in the second member S10 are plate materials that do not form a decorative surface. Such friction stir welding of the first member S9 and the second member S10 is also performed in the same manner as the method already described. That is, first, as shown in FIG. 6A, the end of the plate member S9 ′ of the first member S9 and the second member S9.
10 and the end of the plate material S10 ', but the plate material S
A rotating tool is inserted into the abutting portion T from the decorative surfaces S9a, S10a of 9 ', S10' to perform friction stir welding. next,
As shown in FIG. 6 (b), the first member S9 and the second member S10 are turned upside down to arrange the backing 4 on the decorative surfaces S9a, S10a of the plate materials S9 ′, S10 ′.
By inserting a rotary tool from the non-decorated surfaces S9b, S10b side of 9 ', S10' into the abutting portion T and performing friction stir welding, the decorative surface S9 of the abutting portion T of the plate materials S9 ', S10'.
The a and S10a sides may be made substantially flat. Here, the end portions of the plate material S9 ″ of the first member S9 and the end portions of the plate material S10 ″ of the second member S10 are referred to as plate materials S9 ′, S1.
The friction stir welding is performed at the same time as the friction stir welding from the non-decorative surfaces S9b and S10b of 0 ', but the plate materials S9' and S1
Friction stir welding or welding may be performed before or after the friction stir welding from the 0 ′ non-decorative surface S9b, S10b side.

Further, in the example shown in FIG. 7, the end portions of the plate material S9 'of the first member S9 and the end portions of the plate material S10' of the second member S10 are more than the end portions of the plate materials S9 "and S10", respectively. Although it is different from the example of FIG. 6 in that it protrudes for a long time, the other points are similar to the example of FIG. 6. In this case, the end of the plate material S9 ″ of the first member S9 and the end of the plate material S10 ″ of the second member S10 are not joined. Then, first, as shown in FIG. 7A, the end portions of the plate material S9 ′ of the first member S9 and the end portions of the plate material S10 ′ of the second member S10 are abutted to each other so that the plate materials S9 ′, S10 ′ A rotary tool is inserted into the abutting portion T from the side of the decorative surfaces S9a and S10a to perform friction stir welding, and then the first member S9 and the second member S10 are turned upside down as shown in FIG. 7B. The backing 4 is arranged on the decorative surfaces S9a and S10a of the plate materials S9 ′ and S10 ′, and the plate material S
By inserting a rotary tool from the non-decorated surfaces S9b, S10b side of 9 ', S10' into the abutting portion T and performing friction stir welding, the decorative surface S9 of the abutting portion T of the plate materials S9 ', S10'.
The a and S10a sides may be made substantially flat.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to this, and it should be understood that the present invention should be implemented with appropriate modifications according to the spirit of the invention. Needless to say.

[0034]

<Example 1> The shape of a rotary tool for friction stir welding from the decorative surface side, the shape of a rotary tool for friction stir welding from the non-cosmetic side, and the backing for friction stir welding from the non-cosmetic side In order to study the interrelationship of materials, various combinations of these were actually used for friction stir welding. The test material (plate material) has a thickness of 4 mm, a width of 200 mm, and a length of 200.
A 0 mm aluminum alloy 6N01-T5 was used. In addition, the diameter of the stirring pin of the rotary tool for friction stir welding from the decorative surface side is set to 2.5 mm and the length is set to 1.5 mm, and the rotary tool is rotated around the central axis at 3600 rpm, and along the abutting portion. It was moved at a speed of 1000 mm / min. On the other hand, the diameter of the shoulder part of the rotating tool for friction stir welding from the non-decorative surface side is set to 15 mm, and the length of the stirring pin is set to 3.5 mm.
While rotating at 800 rpm, 400 along the butt
It was moved at a speed of mm / min. The results are shown in Table 1.

[0035]

[Table 1]

From Table 1, the following has become clear. (1) The backing for friction stir welding from the non-decorative side is made of a material having a thermal conductivity larger than that of the plate material (C
In the case of u), if the diameter of the stirring pin of the rotary tool for friction stir welding from the non-decorative side is made larger than the shoulder diameter of the rotary tool for friction stir welding from the decorative side,
The dent on the face side can be corrected flat. (2) When the friction stir welding is performed from the non-decorative surface side, the backing is made of a material having a thermal conductivity smaller than that of the plate material (F
In case of e), if the diameter of the stirring pin of the rotary tool for friction stir welding from the non-decorative side is made larger than 0.5 times the shoulder diameter of the rotary tool for friction stir welding from the decorative side, The dent on the side can be corrected flat. (3) When the friction stir welding is performed from the non-decorative surface side, the backing is made of a material having a thermal conductivity larger than that of the plate material (C
When the material (Fe) having a thermal conductivity smaller than that of the plate material is used, the diameter of the stirring pin of the rotary tool for friction stir welding from the non-decorative surface side can be made smaller than the case of u). This is because the friction stirrer can be kept at a high temperature for a relatively long time by using a backing made of a material having a thermal conductivity smaller than that of the plate material, as described above. It is thought that this is because the effect of correcting the dents is increased.

<Embodiment 2> In order to study the relationship between the material of the backing and the welding speed of the rotary tool when friction stir welding is performed from the non-decorative surface side, various combinations of these are used for actual friction stir welding. went. The thickness of the test material (plate material) is 4
The aluminum alloy 6N01-T5 having a size of 200 mm, a width of 200 mm, and a length of 2000 mm was used. In addition, the diameter of the shoulder part of the rotary tool for friction stir welding from the decorative surface side is 6 mm,
The diameter of the stirring pin was set to 2.5 mm and the length was set to 1.5 mm, and the rotating tool was moved at a speed of 1000 mm / min along the abutting portion while rotating the rotating tool around the central axis at 3600 rpm. On the other hand, the diameter of the shoulder portion of the rotary tool for friction stir welding from the non-decorative surface side was 15 mm, the diameter of the stirring pin was 6 mm, and the length was 3.5 mm. The results are shown in Table 2.

[0038]

[Table 2]

From Table 2, it can be seen that the thermal conductivity of the plate material is higher than that of the material (Cu) having a thermal conductivity larger than that of the plate material as the backing when the friction stir welding is performed from the non-decorative surface side. It can be seen that when the material (Fe) having a smaller thermal conductivity is used, the moving speed in the direction along the butt portion of the rotary tool for friction stir welding from the non-decorative surface side can be increased. This is because the friction stirrer can be kept at a high temperature for a relatively long time by using a backing made of a material having a thermal conductivity smaller than that of the plate material, as described above. It is thought that this is because the effect of correcting the dents is increased.

[0040]

As described above, according to the first aspect of the present invention, the decorative surface side of the butt portion is completely joined and no streak-shaped butt line is left, and sufficient joining strength is obtained. To be Further, since the recesses of the abutting portion caused by the friction stir welding from the decorative surface side are filled by the friction stir welding from the non-decorative surface side, a good-looking decorative surface can be obtained.

According to the invention of claim 2, it is possible to enhance the effect of correcting the dent on the decorative surface side of the abutting portion by friction stir welding from the non-cosmetic surface side.

According to the invention of claim 3, it is possible to enhance the effect of correcting the dent on the decorative surface side of the butt portion by friction stir welding from the non-decorative surface side, and the direction along the butt line of the rotary tool. It is possible to increase the moving speed of the and to bond them efficiently.

According to the invention of claim 4, it is possible to enhance the effect of correcting the dent on the decorative surface side of the abutting portion by friction stir welding from the non-decorative surface side, and to make a cavity or the like on the decorative surface side of the abutting portion. Is less likely to occur.

According to the fifth to eighth aspects of the present invention, it is possible to efficiently manufacture a structure or a vehicle structure having a good appearance and a high joint strength between the plate materials at a low cost.

[Brief description of drawings]

FIG. 1 is a procedure explanatory view showing an embodiment of a friction stir welding method according to the present invention.

FIG. 2 is an explanatory diagram of a procedure following FIG.

3A is a side view of FIG. 1A, and FIG.
It is a side view of (a).

FIG. 4 is a view corresponding to FIG. 2B when the burr excision step of FIG. 1C is omitted.

FIG. 5 is a perspective view showing an embodiment of a vehicle structure manufactured by the friction stir welding method according to the present invention.

FIG. 6 is a sectional view for explaining another embodiment of the friction stir welding method according to the present invention.

FIG. 7 is a sectional view for explaining another embodiment of the friction stir welding method according to the present invention.

[Explanation of symbols]

1… Rotating tool 1a ... Tool body 1b ... Stirring pin 1c ... Shoulder 2… Backing 3… Rotation tool 3b ... Stirring pin 3c ... Shoulder 4… Backing Ba, Bb ... Bali Ha, Hb ... Recess Ka, Kb ... Friction stirrer M ... Groove defect S1, S2 ... Plate material S1a, S2a ... Makeup surface S1b, S2b ... Non-cosmetic surface T… Butt

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Claims (8)

[Claims] 1. A decorative surface side of the plate material, wherein a first member having a plate material forming a decorative surface and a second member having a plate material forming a decorative surface are butted against each other at their ends. After inserting the rotary tool into the abutting portion and performing friction stir welding, arrange a backing on the decorative surface side of the plate material, and from the non-decorative surface side that is the back surface of the decorative surface side of the plate material to the abutting portion. By inserting a rotary tool and performing friction stir welding, the decorative surface side of the butt portion of the plate material is made substantially flat.
A friction stir welding method for a member having a decorative surface. 2. After friction stir welding from the decorative surface side,
The friction stir welding method for a member having a decorative surface according to claim 1, wherein burrs formed on the decorative surface side of the butted portion are removed before the friction stir welding from the non-decorative surface side. 3. The friction stir welding method for a member having a decorative surface according to claim 1 or 2, wherein the backing is made of a material having a lower thermal conductivity than the both plate materials. 4. The rotary tool for friction stir welding from the non-decorative surface side is tilted backward so as to direct the traveling direction, according to any one of claims 1 to 3. A friction stir welding method for a member having the decorative surface described above. 5. A method of manufacturing a structure by the friction stir welding method for a member having a decorative surface according to claim 1. Description: 6. A method of manufacturing a vehicle structure by a friction stir welding method for a member having a decorative surface according to claim 1. Description: 7. A structure manufactured by the friction stir welding method for a member having a decorative surface according to any one of claims 1 to 4. 8. A vehicle structure manufactured by the friction stir welding method for a member having a decorative surface according to any one of claims 1 to 4.