JP3478337B2 - Friction stir welding method of aluminum-based extruded profile and aluminum-based extruded profile for friction-stir welding - Google Patents

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 for aluminum-based extrusion profiles such as aluminum and aluminum alloys, and an aluminum-based extrusion profile for friction stir welding.

[0002]

2. Description of the Related Art As a butt welding method for aluminum-based extruded profile materials such as aluminum and aluminum alloys,
The TIG welding method or the MIG welding method is generally used. However, in these welding methods, since large welding deformation occurs near the welded portion, the deformation is corrected after the welding is completed. There is a laser welding method as a method for reducing such welding deformation, but since this method has a drawback that defects are likely to occur in a welded part, its use has not been generalized.

As a method for solving the above problems,
A probe equipped with a stirring pin protruding downward from the central portion of the concave or flat circular bottom surface is pushed while rotating the stirring pin into the member to be joined in the abutting portion to project the concave or flat circular bottom surface. A friction stir welding method for joining the members to be joined by pressing the upper surface of the members to be joined near the mating portion while moving the probe along the butt line while rotating the probe is disclosed in Japanese Patent Publication No. 7-5050.
It is proposed in Japanese Patent Publication No. 90 and Japanese Patent Publication No. 9-508073.

[0004]

According to the friction stir welding method described above, the above problems can be solved when joining general aluminum-based materials such as flat plate materials, but hollow, C-shaped, L-shaped, etc. In the butt joining performed by abutting and contacting the outer surfaces of ribs of aluminum-based extruded profiles of cross-sectional shape with each other, in the vicinity of the joint due to the vertical pressing force applied by the friction stir welding probe on the upper surface of the member to be joined . Since there is a problem that a joint portion defect is generated due to the deformation of the ribs, it is difficult to apply the friction stir welding method.

The present invention solves the above problems of the prior art.
However, it is also necessary to provide a friction stir welding method for an aluminum-based extruded profile having a hollow, C-shaped, L-shaped, or other cross-sectional shape that does not cause defects such as joint defects due to deformation of ribs near the joint . A second problem is to provide an aluminum-based extruded profile for friction stir welding suitable for application of the friction stir welding method.

[0006]

In order to solve the above-mentioned first problem, the present invention forms a butt portion by abutting the outer surfaces of the ribs of a pair of aluminum-based extruded shape members to form a concave or flat surface. Of a probe equipped with a stirring pin projecting downward from the center of the circular bottom surface of the
Push it into the upper part of both extruded profiles while rotating it, and put the concave or flat circular bottom surface on both extruded profiles near the abutting part.
While pressing on the surface, by moving the probe along the butting line while rotating, the abutting portion both
A friction stir welding method of an aluminum-based extruded profile for joining the upper part of the extruded profile with an outer surface of the stirring pin and an inner peripheral surface of a rib of the extruded profile that are pushed into both upper parts of the extruded profile of the butted portion. The shortest distance w ₁ between them is maintained at 0.6 mm or more and 1.8 mm or less.

In the above invention, the shortest distance w ₁ between the outer surface of the stirring pin and the inner peripheral surface of the rib of the extruded profile , which is pushed into the upper parts of both extruded profiles of the butt section,
It is preferable to keep the distance between 1.2 mm and 1.8 mm.

In order to solve the above-mentioned second problem, the present invention forms a butt portion by abutting the outer surfaces of a pair of ribs of an aluminum-based extruded shape member, and forms a concave portion or a central portion of a flat circular bottom surface. Of the probe provided with a stirring pin projecting downward from the stirring pin while rotating the stirring pin into the upper portions of both extruded shape members of the abutting portion, and the concave or flat circular bottom surface of the extruding type in the vicinity of the abutting portion. While pressing the upper surface of the material , while moving the probe along the butt line while rotating, the aluminum extruded profile for friction stir welding that friction stir welds the upper parts of both extruded profiles of the butt section Planned joint depth h above both extruded profiles at the mating part
In (mm), the shortest distance w ₁ between the outer surface of the stirring pin pushed into the upper portions of both extruded profiles of the abutting portion and the rib inner peripheral surface of the extruded profile is 0.6 mm or more and 1.8 mm. It is formed in advance so as to be kept below.

In the present invention described above, the aluminum-based extruded profile for friction stir welding is pressed on both sides of the abutting portion.
In Dekatachizai top plan junction depth h (mm), the shortest distance w between the ribs in the peripheral surface of the outer surface and the push Degata material of the stirring pin is pushed into both extruded profile over the abutting portion It is preferable to preliminarily form _{1 such} that ₁ is kept at 1.2 mm or more and 1.8 mm or less.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings and specific embodiments.

FIG. 1 is a sectional view for explaining an outline of a friction stir welding method for an aluminum-based extruded shape material according to the present invention and a definition of various dimensions used in the present invention. Extruded profile vertical height H (mm) of aluminum-based extruded profile (hereinafter simply referred to as extruded profile) 1a and 1b with upper and lower plate thickness t (mm)
Each rib 1ar having a minimum thickness of w ₂ (mm)
And the outer surface of 1br are butted and brought into contact with each other to form the butted portion 2. A probe 3 having a diameter D (mm) at the lower end portion provided with a stirring pin 4 having a diameter d (mm) protruding downward from the central portion of a concave or plane circular bottom surface 3b, It is pushed into the upper parts of the extruded profiles 1a and 1b while being rotated, and the concave or flat circular bottom surface 3b of the probe 3 is pressed against the upper surfaces 1af and 1bf of the extruded profiles 1a and 1b in the vicinity of the butting portion 2 by pressing force F ( While pressing with kgf), the probe 3 is rotated while the butt line (extruded profile 1a,
By moving along the longitudinal direction (1b), the upper portions of the extruded profiles 1a and 1b of the butted portion 2 are friction stir welded. In addition, w ₁ (mm) is the outer surface of the stirring pin 4 and the ribs 1ar of the extruded profiles 1a, 1b, and the rib inner peripheral surfaces 1as, 1bs of the 1br.
Shows the shortest distance between. The extruded shape members 1a and 1b
If the ribs 1ar and 1br have different minimum thicknesses,
The smaller thickness is used as w ₂ (mm).

1. Example 1 FIG. 2 is a cross-sectional view showing the positional relationship between the shape and dimensions of the butt-aluminum-based extruded shape member used for friction stir welding of this example and the stirring pin 4 for friction stir welding. In FIG. 2, a probe 3 having a lower end diameter D = 15 mm equipped with a stirring pin 4 whose diameter is d = 4 mm and whose lower end is chamfered with a radius of curvature r = 4 mm is used. To the lower end of the outer peripheral surface of the stirring pin 4 (hereinafter referred to as the planned joining depth) h of 3.0 mm, 4.0 mm and 5.0 mm respectively, the radius of curvature R of the inner peripheral surface of the rib is 8 mm. In the case, the shortest distance w ₁ (mm) between the outer surface of the stirring pin 4 and the rib inner peripheral surface 1bs is on the right side of the abutting portion 2 in the figure, and the rib inner circumference is at the predetermined joining depth h of 4.0 mm. Radius of curvature R of surface 1as
= 8 mm and R = 6 mm, the shortest distance w ₁ (mm) between the outer surface of the stirring pin 4 and the rib inner peripheral surface ₁ as is shown on the left side of the abutting portion 2 in the figure. The material used is aluminum alloy extruded shape material 6063-T5 material shown in "JIS H 4100".

As shown in FIG. 2, when the radius of curvature R of the inner peripheral surface of the rib is 8 mm, the height of the stirring pin 4 is changed to change the planned joining depth h (mm), and the stirring pin 4 is changed. The effect of the shortest distance w ₁ (mm) between the outer surface and the inner peripheral surface of the rib of _{No. 4} on the quality of the friction stir welding part was investigated. Also, by fixing the planned joining depth h (mm) and changing the radius of curvature R of the rib inner peripheral surface, the shortest distance w ₁ (mm) between the outer surface of the stirring pin 4 and the rib inner peripheral surface is The effect on friction stir weld quality was investigated. The above survey results are shown in Table 1 below.

[0014]

[Table 1]

As shown in Table 1, when w ₁ is 0.5 mm or less, large hollow defects occur at the bottom of the joint, and when w ₁ is 0.6 mm, small points that cannot be visually identified. Defects occurred. When w ₁ was 1.2 mm or more, a sound joint having no defect was obtained.

2. Example 2 The shape and dimensions of the extruded aluminum base material used in this example are shown in FIG. The shapes and dimensions of the probe 3 and the stirring pin 4 are the same as those used in the first embodiment. The material used is aluminum alloy extruded shape material 6N01-T5 material shown in "JIS H 4100". By changing the depth h (mm) of the stirring pin 4 pushed into the upper part of the butt of the extruded shape, the shortest distance w ₁ (mm) between the outer surface of the stirring pin 4 and the inner peripheral surface of the rib is friction stir. The effect on the quality of the joint was investigated. The results of the investigation are shown in Table 2 below.

[0017]

[Table 2]

According to Table 2 above, when w ₁ is 0.4 mm or less, a large hollow defect is generated at the bottom of the joint, as in the case of w ₁ of 0.5 mm or less in the _first embodiment. _{When 1} was 0.8 mm, small dot defects which could not be visually identified occurred. When w ₁ was 1.2 mm or more, a sound joint having no defect was obtained.

The results of Table 1 of Example 1 above and Example 2 above
Combining with the results of Table 2 in Table _1, the shortest distance w ₁ between the outer surface of the stirring pin and the inner peripheral surface of the rib is at least 0.6 mm or more,
It is preferable that the thickness is 1.2 mm or more.

Further, at the predetermined joining depth h (mm) above the extruded profile of the butt section, the outer surface of the stirring pin pushed into the upper section of the extruded profile of the butt section and the rib of the extruded profile. If the aluminum-based extruded profile for friction stir welding is formed in advance so that the shortest distance w ₁ to the peripheral surface is maintained at 0.6 mm or more, the joint portion will not be visible as described above during friction stir welding. Since only defects are generated, the friction stir welding material of the aluminum-based extruded profile can be used sufficiently if it is not required to have mechanical strength.

Further, at a predetermined joining depth h (mm) above the extruded profile of the butt section, the outer surface of the stirring pin pushed into the upper section of the extruded profile of the butt section and the extruded profile of the extruded profile. If an aluminum-based extruded profile for friction stir welding is formed in advance so that the shortest distance w ₁ between the rib inner peripheral surface is 1.2 mm or more, as described above, defects in the joint during friction stir welding will occur. Since it does not occur at all, even if the friction stir welding material of the aluminum-based extruded shape material is required to have severe mechanical strength, it can be sufficiently used.

By the way, the cause of the above-mentioned hollow defects generated at the bottom of the friction stir welded part will be considered as follows, including observations during experiments. (1) When the shortest distance w ₁ between the outer surface of the stirring pin 4 and the inner circumferential surface of the rib is 0.5 mm or less, as shown in the diagram on the left side of FIG. When the thin rib between the outer surface of No. 4 and the inner peripheral surface of the rib of the profile is greatly deformed so as to spread to the outside, and the deformation amount is large, the inner volume of the bottom portion of the joint near the lower portion of the stirring pin 4 is increased. Is so large that it can be visually observed. Therefore, as shown in the diagram on the right side of FIG.
Metal supplementation to the bottom portion due to plastic flow is insufficient, and the insufficient amount is large, resulting in large visually recognizable hollow defects d _fl at the bottom portion of the joint. (2) On the other hand, when the shortest distance w ₁ between the outer surface of the stirring pin 4 and the inner peripheral surface of the rib is 0.6 mm or more and less than 1.2 mm,
As shown in the diagram on the left side of (b), the thin rib between the outer surface of the stirring pin 4 and the rib inner peripheral surface as described above may be deformed so as to slightly spread to the outside. Is small, and therefore the expansion of the internal volume of the bottom of the joint near the lower part of the stirring pin 4 is not so large that it can be visually observed. Therefore, FIG.
As shown in the diagram on the right side of (b), even if the metal supplementation to the bottom portion due to plastic flow is insufficient, the insufficient amount is not so large, and as a result, the bottom portion of the joint cannot be visually identified. Point-like defects d _fs occur. (3) When the shortest distance w ₁ between the outer surface of the stirring pin 4 and the inner peripheral surface of the rib becomes 1.2 mm or more, which is sufficiently thick, as shown in the left side diagram of FIG. As described in the item (2), the rib is never deformed so as to expand to the outside. Therefore, there is no shortage of metal replenishment due to plastic flow, and the right side of FIG. As shown in the figure, the above-described hollow or dot-like defects at the bottom of the joint do not occur.

3. Example 3 Next, in Examples 1 and 2 described above, a condition in which a joint defect (dot-like defect) that could not be visually discriminated was generated, that is, between the outer surface of the stirring pin and the inner peripheral surface of the rib of the profile. When the shortest distance w ₁ between them is 0.6 mm or more and less than 1.2 mm, the rib inner peripheral surface is (1) without cooling (natural cooling),
(2) Compressed air blowing cooling, (3) Cooling water spray cooling,
Friction stir welding was performed while cooling at three cooling levels, and the effect of the cooling level on the quality of the friction stir welding part was investigated. The results of the investigation are shown in Table 3 below.

[0024]

[Table 3]

According to Table 3 above, when the shortest distance w ₁ between the outer surface of the stirring pin and the inner peripheral surface of the rib is 0.6 mm or more and less than 1.2 mm, (1) without cooling (natural cooling) As in Tables 1 and 2, the occurrence of joint defects (dot defects) that could not be visually discriminated was observed. However, (2) compressed air blowing cooling and (3) cooling water spray cooling In this case, a good quality of the friction stir welded portion could be obtained without the occurrence of a welded portion defect (dot defect) that could not be visually discriminated.
Therefore, when the shortest distance w ₁ between the outer surface of the stirring pin and the inner peripheral surface of the rib is 0.6 mm or more and less than 1.2 mm, the inner peripheral surface of the rib is cooled by blowing with compressed air or a cooling water spray cooling method. It is preferable that the positive cooling is performed to prevent the occurrence of defects in the joint and improve the quality of the joint.

4. Example 4 FIG. 5 of the aluminum alloy extruded shape members 6N01-T5 and 6N01-T1 specified in “JIS H 4100”.
The rectangular cross-section shape and shape as shown in Fig. 4 are friction stir welded in the longitudinal direction (direction perpendicular to the paper surface of Fig. 5) by abutting and contacting the outer surfaces of the ribs 1r with each other. I went. At this time, the joint depth (depth from the top surface of the profile to the lower end of the outer circumference of the stirring pin) h = 2 mm, the shortest distance w ₁ = 5 mm between the outer surface of the stirring pin and the inner peripheral surface of the rib, and the lower end of the probe. Diameter D = 10mm, probe pressure F = 250
Under a constant condition of kgf, the height H of the extruded profile is 50 to
Deformation of the above formula 1 by gradually changing it between 400 mm
The buckling limit thickness w _2A (mm) and the deformation / buckling limit thickness w _2B (mm) of the above formula 2 are changed, and these w _2A , w _2B and rib 1r are changed.
The influence of the magnitude relation with the minimum thickness w ₂ on the joint quality was investigated. The results of the investigation are shown in Table 4 below.

[0027]

[Table 4]

The following can be said from Table 4 above. (1) 6N01-T5 material (proof stress σ _0.2 = 225 N / mm ² )
Then, when the thickness w ₂ of the minimum thickness portion of the rib was 1 mm, no defect was generated in the joint portion. At this time, w ₂ > w _2B and w ₂ > w _2A were satisfied in all cases where the height H of the extruded profile was 50 to 400 mm. (2) With the same material as in (1) above, when the minimum thickness w ₂ of the rib is 0.75 mm, w ₂ > w in all cases
_It met the condition of _2B . Then, when the height H of the extruded profile was up to 100 mm, that is, when w ₂ > w _2A, no joint defect occurred. Height of extruded shape H = 200m
In the case of m, that is, w ₂ = w _2A , defects that could not be visually identified occurred. Height of extruded shape H = 300mm
In (w ₂ <w _2A ), a heavy defect occurs, and the rib height H = 4.
It was impossible to bond with 00 mm (w ₂ << w _2A ). (3) In 6N01-T1 material (proof stress σ _0.2 = 90 N / mm ² ), when the thickness w ₂ of the minimum thickness portion of the rib is 1 mm, even if the height H of the extruded profile is 100 mm or less, A defect has occurred. At this time, w ₂ > w _2A , but w ₂ <w
It was _2B . (4) With the same material as in (3) above, when the thickness w ₂ of the minimum thickness part of the rib is increased to 1.5 mm, w ₂ > W _2B , and
Since w ₂ > w _2A , a sound joint having no defects was obtained.

5. Example 5 The same two types of materials as in Example 4 were used, and the same rectangular cross-section hollow extruded shape as shown in FIG. 5 as in Example 4 was used. Were butt-contacted with each other and friction stir welding was performed in the longitudinal direction (direction perpendicular to the paper surface of FIG. 5). Joint depth at this time h =
4 mm, the shortest distance w between the outer surface of the stirring pin and the inner peripheral surface of the rib
₁ = 5 mm, the diameter D of the lower end of the probe D = 15 mm, and the pressing force F of the probe F = 400 kgf under constant conditions, the vertical height H of the extruded profile is changed stepwise between 50 and 400 mm, formula varied first and deformation-buckling limit thickness w _2A deformed or buckling limit thickness w _2B of the formula 2, the thickness of the thinnest portion of these variations and buckling limit thickness w _2A, w _2B rib 1r w ₂
The effect of the magnitude relation between the and the relationship on the joint quality was investigated. The results of the investigation are shown in Table 5 below.

[0030]

[Table 5]

The following can be said from Table 5 above. (1) 6N01-T5 material (proof stress σ _0.2 = 225 N / mm ² )
Then, when the thickness w ₂ of the minimum thickness portion of the rib was 1 mm and the height H of the extruded profile was 50 to 300 mm, no defect was generated in the joint portion. At this time, the height H of the extruded profile is 50 to
In any case of 300 mm, w ₂ > w _2A and w ₂ >
It was w _2B . However, the height of the extruded shape H = 400 mm
In the case of (w ₂ ≈w _2A and w ₂ > w _2B ), a defect that could not be visually identified occurred at the joint. (2) When the thickness w ₂ of the minimum thickness part of the rib is 0.75 mm with the same material as in (1) above, w ₂ > w _{2B in} all cases
Was satisfied. And the height H of the extruded profile
Up to 100 mm, that is, when w ₂ > w _2A, no joint defect occurred. Height of extruded shape H = 200-3
When it was 00 mm, that is, when w ₂ <w _2A , a joint defect occurred. Height of extruded profile H = 400mm (w ₂ << w _2A )
It was impossible to join. (3) In 6N01-T1 material (proof stress σ _0.2 = 90 N / mm ² ), when the thickness w ₂ of the minimum thickness portion of the rib is 1 mm, the joint defect is caused even when the height H of the extruded profile is 50 mm. There has occurred. At this time, w ₂ > w _2A , but w ₂ <w _2B . (4) When the thickness of the minimum thickness portion of the rib is increased to w ₂ = 1.5 mm using the same material as in (3) above, w ₂ > w _2A and w ₂ = w _2B , which cannot be visually determined. A joint defect has occurred. (5) When the thickness of the minimum thickness portion of the rib is increased to w ₂ = 2.0 mm with the same material as (3) above, w ₂ > w _2A and w ₂ > w _2B , and there is no defect and soundness. A good joint was obtained.

The findings from Table 4 of Example 4 and Table 5 of Example 5 are summarized as follows. (1) Even when the thickness w ₂ (mm) of the minimum thickness portion of the rib of the aluminum-based extruded profile is equal to or more than the first deformation / buckling limit thickness w _2A (mm) defined by the above formula 1, If the thickness is smaller than the second deformation / buckling limit thickness w _2B (mm) defined by Equation 2, a joint defect occurs or joining becomes impossible, and w ₂ (m
When m) is equal to w _2B (mm), defects that cannot be visually discerned occur. From this, it is necessary to satisfy w ₂ ≧ w _2A and w ₂ ≧ w _2B in order to allow the occurrence of defects that cannot be visually discriminated and to prevent the occurrence of joint defects. (2) Even if the condition of w ₂ ≧ w _2B is satisfied as described above, w ₂ is the first buckling limit thickness w defined by the above formula 1.
If it is less than _{2 A, a} joint defect occurs and w ₂ is the above w.
If it is equal to _{2 A} , defects that cannot be visually discerned will occur. From this, it is necessary to satisfy w ₂ ≧ w _2A and w ₂ ≧ w _2B in order to allow the occurrence of defects that cannot be visually discriminated and to prevent the occurrence of joint defects.

Therefore, in order to allow the occurrence of defects that cannot be visually discerned in the friction stir welding portion, the shortest distance w ₁ between the outer surface of the stirring pin and the inner peripheral surface of the rib is kept at 0.6 mm or more. At the same time, the aluminum-based extruded profile for friction stir welding should be formed in advance so that the thickness w ₂ (mm) of the minimum thickness part of the rib forming the abutting part satisfies the following formulas 1 and 2. Is desirable. w ₂ ≧ w _2A = {(F × H) / (1439 × D)} ^3/2/2 ………… Equation 1 w ₂ ≧ w _2B = F / (2 × D × σ _0.2 ) ………… Formula 2 Here, w _2A : first deformation / buckling limit thickness (mm) w _2B : second deformation / buckling limit thickness (mm) F; probe pressing force (kgf) D; probe lower end Diameter (mm) σ _0.2 ； Proof strength of aluminum extruded profile (kgf / mm ² ) H ； Vertical height of extruded profile (vertical height of butt section) (mm)

Further, when the friction stir welding part is used in a severe application where the occurrence of defects that cannot be visually discerned cannot be tolerated, the abutting surface is maintained while keeping the shortest distance w ₁ at 1.2 mm or more. It is preferable to preliminarily form the aluminum-based extruded profile for friction stir welding so that the thickness w ₂ (mm) of the minimum thickness portion of the rib that forms the above formula satisfies the following formula 1 ′ and the following formula 2 ′. w ₂ > w _2A = {(F × H) / (1439 × D)} ^3/2/2 ………… Equation 1 ′ w ₂ > w _2B = F / (2 × D × σ _0.2 ) ……… ... Equation 2 '

It is considered that the joint defect that occurs when the thickness w ₂ of the minimum thickness portion of the rib forming the abutting surface does not satisfy the above condition is as follows. That is, (1) The thickness w ₂ of the minimum thickness portion of the rib is such that the ribs facing each other as shown in FIG. 6 with respect to the pressing force F (kgf) of the probe 3 are bent toward the inner surface side of each profile. Alternatively, when either of w _2A given by the above formula 1 and w _2B given by the above formula 2 as the deformation / buckling limit thickness that does not cause buckling becomes less than or equal to each other, as shown in FIG. Deformation and buckling occur such that a gap 2g is generated between the ribs 1ar and 1br that are in contact with each other, and the gap 2g thus generated extends to the upper joint between the extruded profiles 1a and 1b to be joined and continues in the joining direction. If a hollow defect occurs, or in extreme cases, it becomes impossible to join. (2) When the thickness w ₂ of the minimum thickness portion of the rib is sufficiently larger than one of the values of w _2A and w _2B and is substantially equal to the other one of the values, the deformation The degree of buckling does not increase so much, and the resulting gap 2g is relatively narrow.
When the effect on the upper joints of 1 and 1b is not so large, it is considered that the occurrence of defects that cannot be visually discerned will suffice.

Although the embodiment of the present invention has been described based on the specific embodiment, the present invention is not limited to this, and other embodiments are possible within the scope of the gist of the invention. It goes without saying that it also includes the aspect of. For example, in the above-mentioned embodiment, the specific material of the aluminum alloy extruded shape is used, and the test material mainly including the hollow shape having the square cross section is described. It is also applicable to the butt friction stir welding method in which the outer surface of the rib of an aluminum-based extruded shape having a hollow shape other than a rectangular cross section or a C-shaped or L-shaped cross-section is abutted and contacted. In addition, the present invention can also be applied to an aluminum-based extruded profile used for such friction stir welding.

[0037]

The present invention has the following excellent effects. That is, according to (1) the friction stir welding method for an aluminum-based extruded shape material of the present invention and the aluminum-based extruded shape material for a friction stir welding according to the present invention, a butt portion is formed when the outer surfaces of the ribs are butted. The quality of the friction stir welded joint can be obtained which is sufficiently acceptable even for applications where the joint strength is not so demanding, as it allows a hollow defect at the bottom of the joint that cannot be visually discerned due to a small deformation of the upper rib. (2) According to the friction stir welding method for an aluminum extruded profile of the present invention and the aluminum extruded profile for friction stir welding of the present invention, when the outer surfaces of the ribs are butted, the upper part of the butted portion is joined. It is possible to prevent the occurrence of hollow defects at the bottom of the joint due to the deformation of the ribs, and to obtain the quality of the friction stir welded joint that is sufficiently compatible with the use where the joint strength is relatively strict .

[Brief description of drawings]

FIG. 1 is a cross-sectional view for explaining an outline of a friction stir welding method for an aluminum-based extruded shape material according to the present invention and a definition of various dimensions used in the present invention.

FIG. 2 is a sectional view of a probe for friction stir welding used in Example 1 of the present invention, a sectional size of an extruded profile using the probe, and a radius of curvature of a rib inner peripheral surface as parameters.
FIG. 6 is a cross-sectional view showing the relationship between the welding depth h and the shortest distance w ₁ between the tip of the outer peripheral surface of the stirring pin and the inner peripheral surface of the rib during friction stir welding.

FIG. 3 is a cross-sectional view showing cross-sectional dimensions of an aluminum-based extruded profile and a probe used in Example 2 of the present invention.

FIG. 4 is a cross-sectional view showing a mechanism of generation of a hollow defect at a bottom portion of a joint portion due to deformation of a rib at an upper portion of a butt portion of an aluminum-based extruded shape member.

FIG. 5 is a cross-sectional view that defines and shows the cross-sectional dimensions of the extruded profiles used in Examples 4 and 5 of the present invention.

FIG. 6 is a cross-sectional view showing a mechanism of generation of a joint defect due to deformation / buckling of a minimum thickness portion of a rib of an aluminum-based extruded shape member.

[Explanation of symbols]

1, 1a, 1b Extruded profile 1r, 1ar, 1br rib 1as, 1bs rib inner peripheral surface 2 Butt 2g gap 3 probes 4 stirring pins 5 joints

Continuation of the front page (56) Reference JP-A-9-309164 (JP, A) JP-A-10-286682 (JP, A) JP-A-11-58036 (JP, A) JP-A-10-328856 (JP , A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B23K 20/12

Claims (4)

(57) [Claims] 1. A probe provided with a stirring pin, which is formed by abutting outer surfaces of a pair of ribs of an aluminum-based extruded profile with each other to form a butted portion, and which projects downward from a central portion of a concave or flat circular bottom surface. both extrusion butt portion of the stirring pin
By pushing while rotating into the upper part of the profile, pressing the concave or flat circular bottom surface against the upper surface of both extruded profiles near the abutting part, while moving the probe along the abutting line while rotating , Butt extruded type
In a friction stir welding method of an aluminum-based extruded profile for joining upper parts of a material , in the outer surface of the stirring pin pushed into the upper parts of both extruded profiles of the abutting portion and the rib inner peripheral surface of the extruded profile . A friction stir welding method for extruded aluminum-based profiles, characterized in that the shortest distance w ₁ between them is maintained at 0.6 mm or more and 1.8 mm or less. 2. The shortest distance w ₁ between the outer surface of the stirring pin and the inner peripheral surface of the rib of the extruded profile , which is pushed into the upper parts of both extruded profiles of the butted portion, is 1.2 mm or more. The method for friction stir welding of an aluminum-based extruded profile according to claim 1, wherein the method is maintained at 1.8 mm or less. 3. A probe having a stirrer pin formed by abutting the outer surfaces of a pair of ribs of an aluminum-based extruded profile with each other to form a butt portion and projecting downward from a central portion of a concave or flat circular bottom surface. both extrusion butt portion of the stirring pin
By pushing while rotating into the upper part of the profile, pressing the concave or flat circular bottom surface against the upper surface of both extruded profiles near the abutting part, while moving the probe along the abutting line while rotating , Butt extruded type
An aluminum-based extruded shape member for friction stir welding, which joins the upper parts of the members by friction welding, in the upper part of both extruded shape members of the abutting part at a predetermined joining depth h of the upper part of both extruded shape members of the abutting part . The friction is characterized in that it is formed in advance so as to keep the shortest distance w ₁ between the outer surface of the stirring pin to be pushed into and the inner peripheral surface of the rib of the extruded profile to be 0.6 mm or more and 1.8 mm or less. Aluminum extruded profile for stir welding. In 4. expected junction depth h of both extruded profile above the abutting portion, wherein the rib inner peripheral surface of the outer surface and the push Degata material of the stirring pin is pushed into both extruded profile The aluminum-based extruded profile for friction stir welding according to claim 3, which is formed in advance so as to keep the shortest distance w ₁ between 1.2 mm and 1.8 mm.