JP3262161B2 - 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 extruded members such as aluminum and aluminum alloys, and an aluminum-based extruded member for friction stir welding.

[0002]

2. Description of the Related Art A butt welding method for extruded aluminum-based materials such as aluminum and aluminum alloys includes:
The TIG welding method or the MIG welding method is generally used. However, in these welding methods, since a large welding deformation occurs near the welded portion, the deformation is corrected after the welding is completed. As a method of reducing such welding deformation, there is a laser welding method. However, this method has a drawback that a defect is easily generated in a welded portion, and therefore its use has not been generalized.

[0003] As a method of solving the above problems,
A probe provided with a stirring pin protruding downward from the center of the concave or flat circular bottom is pressed while rotating the stirring pin into the member to be joined of the butting portion, and protrudes from the concave or flat circular bottom. The friction stir welding method for joining the members to be joined by rotating and moving the probe along the butting line while pressing against the upper surface of the members to be joined near the joining portion is disclosed in Japanese Patent Application Laid-Open No. Hei 7-5050.
No. 90 and Japanese Patent Publication No. 9-508073.

[0004]

According to the above-mentioned friction stir welding method, the above problem can be solved in the joining of a general aluminum-based material such as a flat plate material. In the butt joining in which the rib outer surfaces of an aluminum-based extruded section having a cross-sectional shape are butt-contacted with each other, a vertical pressing force applied by a friction stir welding probe to the upper surface of a member to be welded causes the vertical rib portion to be pressed. There has been a problem of deformation, buckling, or occurrence of a joint defect due to deformation of a rib near the joint, and it has been difficult to apply the friction stir welding method.

[0005] The present invention solves the above-mentioned problems of the prior art, and eliminates the occurrence of deformation or buckling of the rib minimum thickness portion or the occurrence of joint defects due to deformation of the rib near the joint. The first object of the present invention is to provide a method of friction stir welding of an aluminum-based extruded profile having a cross-sectional shape such as a C-shape or an L-shape, which is suitable for application of the friction stir welding method. Providing materials is a second issue.

[0006]

According to the present invention, in order to solve the above-mentioned first problem, the outer surfaces of ribs of an extruded aluminum material are joined to each other to form an abutting portion, and a concave or flat circular shape is formed. A probe having a stirring pin protruding downward from the center of the bottom surface, while rotating and pushing the stirring pin into the upper part of the extruded profile of the butting portion, and bringing the concave or flat circular bottom surface near the butting portion. While pressing against the upper surface of the extruded profile, the probe is rotated and moved along the butt line, whereby the friction stir welding method of the aluminum-based extruded profile that joins the extruded profile upper portion of the butt portion, maintaining a minimum distance w ₁ between the ribs in the peripheral surface of the outer surface and the push Degata material of the stirring pin is pushed into the extruded profile upper butt portions above 0.6 mm, Li of the extruded shape member
The friction stir welding is performed while cooling the inner peripheral surface of the bush .

[0007]

[0008]

In order to solve the above-mentioned second problem, the present invention forms an abutting portion by abutting the outer surfaces of ribs of an extruded aluminum-based material, and forms a butted portion from the center of a concave or flat circular bottom surface. The probe provided with a stirring pin protruding into the probe is rotated and pushed into the upper part of the extruded profile of the butted portion, and the concave or flat circular bottom is pressed against the upper surface of the extruded profile near the butted portion. while, by moving along the butting line while rotating the probe, the friction stir welding aluminum-based extruded profile for friction stir welding the extruded profile upper butt portions, extrusion of the abutting portion The shortest distance w ₁ between the outer surface of the agitating pin pushed into the upper part of the extruded profile of the butting portion and the inner peripheral surface of the rib of the extruded profile at the planned joining depth h (mm) of the upper profile. 0.6 mm or less Formed in advance so as to keep the front
Thickness of the minimum thickness of the extruded rib that forms the butted part
So that w ₂ satisfies the following equations 1 and 2
It is formed and configured. w ₂ ≧ w _2A = {(F × H) / (1439 × D)} ^3/2 / 2 Formula 1 w ₂ ≧ w _2B = F / (2 × D × σ _0.2 ) here equation 2, w _2A: first deformation and buckling limit thickness (mm) w _2B: second deformation and buckling limit thickness (mm) F; pressing force of the probe (kgf) D; probe lower end Diameter (mm) σ _0.2 ; Strength of extruded aluminum material (kgf / mm ² ) H; Vertical height of extruded material (vertical height of butt) (mm)

[0010] In the present invention, the aluminum-based extruded section for friction stir welding is formed by extruding the extruded section of the butt section at a predetermined joining depth h (mm) above the extruded section of the butt section. The shortest distance w ₁ between the outer surface of the stirring pin pushed into the upper part and the inner peripheral surface of the rib of the extruded profile is set to 1.
It is preferable to form them in advance so as to keep them at 2 mm or more.

[0011]

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings and specific embodiments.

FIG. 1 is a cross-sectional view for explaining the outline of the friction stir welding method for an aluminum-based extruded profile according to the present invention and the definition of various dimensions used in the present invention. Aluminum extruded profiles (hereinafter simply referred to as extruded profiles) 1a and 1b each having a thickness t (mm) of the upper and lower plates and a vertical height H (mm) of the extruded profile.
Each rib 1ar whose minimum thickness is w ₂ (mm)
And the outer surfaces of the 1 br are butted and brought into contact with each other to form a butted portion 2. The probe 3 having a diameter D (mm) at the lower end provided with a stirring pin 4 having a diameter d (mm) projecting downward from the center of the concave or flat circular bottom surface 3b The concave or flat circular bottom surface 3b of the probe 3 is pushed into the upper portions of the extruded members 1a and 1b while rotating, and the upper surfaces 1af and 1bf of the extruded members 1a and 1b near the abutting portion 2 are pressed with a pressing force F ( kgf), while rotating the probe 3 while pressing, the butt line (extruded material 1a,
1b), the upper portions of the extruded sections 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 rib inner surfaces 1as, 1bs of the ribs 1ar, 1br of the extruded profiles 1a, 1b.
The shortest distance between The extruded members 1a, 1b
If the minimum thickness of the ribs 1ar and 1br is different,
The smaller thickness is used as w ₂ (mm).

1. Embodiment 1 FIG. 2 is a cross-sectional view showing the positional relationship between the shape and dimensions of a butt-extruded aluminum-based extruded member used for friction stir welding of the present embodiment and a stirring pin 4 for friction stir welding. In FIG. 2, a probe 3 having a diameter d = 4 mm and a lower end D = 15 mm provided with a stirring pin 4 chamfered at the lower end with a radius of curvature r = 4 mm is used. When the depth h (hereinafter, referred to as the planned joining depth) h of the stirring pin 4 is 3.0 mm, 4.0 mm, and 5.0 mm, the radius of curvature R of the inner circumferential surface of the rib is 8 mm. In this case, the shortest distance w ₁ (mm) between the outer surface of the stirring pin 4 and the inner circumferential surface 1bs of the rib is set on the right side of the butting portion 2 in the drawing, and the predetermined joining depth h is 4.0 mm and the inner circumferential surface of the rib is 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 inner circumferential surface 1as of the rib is shown on the left side of the butted portion 2 in the figure. The material used was an extruded aluminum alloy 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 planned joining depth h (mm) is changed by changing the height of the stirrer pin 4 and the stirrer pin is changed. The effect of the shortest distance w ₁ (mm) between the outer surface of _No. 4 and the inner peripheral surface of the rib on the quality of the friction stir weld was examined. Further, by fixing the planned joining depth h (mm) and changing the radius of curvature R of the inner peripheral surface of the rib, the shortest distance w ₁ (mm) between the outer surface of the stirring pin 4 and the inner peripheral surface of the rib is reduced. The effect on the quality of friction stir welds was investigated. The above investigation results are shown in Table 1 below.

[0016]

[Table 1]

As shown in Table 1, when w ₁ is 0.5 mm or less, a large hollow defect occurs at the bottom of the joint, and when w ₁ is 0.6 mm, a small dot that cannot be visually discriminated is formed. A state defect occurred. w ₁ it was totally obtained healthy joints without defects in 1.2mm or more.

2. Example 2 FIG. 3 shows the shape and dimensions of the extruded aluminum-based material used in this example. 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 an aluminum alloy extruded shape 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 butted portion of the extruded profile, the shortest distance w ₁ (mm) between the outer surface of the stirring pin 4 and the inner peripheral surface of the rib is changed by friction stirring. The effect on joint quality was investigated. The results of the investigation are shown in Table 2 below.

[0019]

[Table 2]

According to Table 2, when w ₁ is 0.4 mm or less, a large hollow defect is generated at the bottom of the joint, similarly to the case where w _{1 in} Example ₁ is 0.5 mm or less. _{When 1} was 0.8 mm, a small point defect that could not be visually identified was generated. w ₁ is healthy joints without defects was obtained by 1.2mm or more.

The results in Table 1 of Example 1 and Example 2 above
When the results of Table 2 are combined, 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,
Preferably, it should be at least 1.2 mm.

Further, at a predetermined joining depth h (mm) at the upper part of the extruded section at the butt section, the outer surface of the stirring pin pushed into the upper section of the extruded section at the butt section and the inside of the rib of the extruded section are formed. the shortest distance w ₁ between the peripheral surface so as to maintain the above 0.6 mm, be previously form the friction stir welding aluminum-based extruded profile, joints which can not be said visible as during the friction stir welding Since only defects occur, the friction stir welding material of the extruded aluminum-based material can sufficiently withstand use if it does not require very high mechanical strength.

Further, at a predetermined joining depth h (mm) at the upper part of the extruded profile of the butted portion, the outer surface of the stirring pin pushed into the upper part of the extruded profile of the butted portion and the outer surface of the extruded profile are formed. the shortest distance w ₁ a so as to maintain the above 1.2 mm, be previously form the friction stir welding aluminum-based extruded profile, the joint defect during the friction stir welding as in between the ribs in the peripheral surface Therefore, even if the use of the friction stir welding material of the aluminum-based extruded shape is a use requiring strict mechanical strength or the like, it can be sufficiently used.

By the way, the cause of the occurrence of the hollow defect generated at the bottom of the friction stir welding portion as described above, including observation during the experiment, is as follows. (1) If the shortest distance w ₁ between the outer surface and the ribs in the peripheral surface of the stirring pin 4 is 0.5mm or less, as shown in the left drawing of FIG. 4 (a), the stirring pin as described above The thin rib between the outer surface of the rib 4 and the inner peripheral surface of the rib is largely deformed so as to spread outward, and when the amount of deformation is large, the inner volume of the bottom of the joint near the lower part of the stirring pin 4 is increased. Is large enough to be seen. Therefore, as shown in the right side of FIG.
Insufficient metal replenishment due to plastic flow to the bottom causes a large amount of the shortage, resulting in a large hollow defect d _fl that can be visually identified at the bottom 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, FIG.
As shown in the figure on the left side of (b), the thin rib between the outer surface of the stirring pin 4 and the inner peripheral surface of the rib as described above may be deformed so as to slightly spread outward. Therefore, the expansion of the inner volume of the joint bottom near the lower portion of the stirring pin 4 is not so large as to be visible. Therefore, FIG.
As shown in the figure on the right side of (b), even if the replenishment of the metal by the plastic flow to the bottom is insufficient, the amount of the shortage is not so large, and as a result, the bottom of the joint cannot be visually discriminated. A point defect _dfs is generated. (3) When the shortest distance w ₁ between the ribs in the circumferential surface of the outer surface of the stirring pin 4 is sufficiently thick and 1.2mm or more, as shown in the left drawing of FIG. 4 (C), the above (1) As described in the section (2), the ribs are not deformed so as to spread outward, so that there is no shortage of metal replenishment due to plastic flow, and the rib on the right side of FIG. As shown, there is no occurrence of a hollow or point-like defect at the bottom of the joint as described above.

3. Third Embodiment Next, in the first and second embodiments, the condition in which a joint defect (point defect) to the extent that it cannot be visually discriminated was generated, that is, the difference between the outer surface of the stirring pin and the inner peripheral surface of the rib of the profile was found. when the shortest distance w ₁ between is less than 1.2mm or 0.6 mm, the rib inner peripheral surface, (1) no cooling (natural cooling),
(2) compressed air spray cooling, (3) cooling water spray cooling,
The friction stir welding was performed while cooling at the three cooling levels, and the effect of the cooling level on the quality of the friction stir weld was investigated. The results of the investigation are shown in Table 3 below.

[0026]

[Table 3]

According to Table 3, 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) In the same manner as in Tables 1 and 2, occurrence of joint defects (point-like defects) to the extent that they could not be visually discriminated was recognized, but (2) compressed air spray cooling and (3) cooling water spray cooling. In this case, there was no occurrence of a joint defect (point defect) to the extent that it could not be visually discriminated, and good friction stir welding quality could be obtained.
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 a compressed air spray cooling method or a cooling water spray cooling method. It is preferable to perform active cooling by the method described above in order to prevent occurrence of joint defects and improve joint quality.

4. Example 4 The aluminum alloy extruded profiles 6N01-T5 and 6N01-T1 specified in "JIS H 4100" were formed into rectangular hollow sections having the shapes and dimensions as shown in FIG. the outer surface between the 1 _r by butt-contact, was longitudinal friction stir welding (direction perpendicular to the plane of FIG. 5). Depth of the joint at this time (depth from the upper surface of the profile to the lower end of the outer periphery 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 pressing force F = 25
Under a constant condition of 0 kgf, the height H of the extruded profile is 50
Stepwise varied between ～400Mm, alter the above formula 1 of the deformation and buckling limit thickness w _2A (mm) and the deformation and buckling limit thickness w _2B of the formula 2 (mm), these w _2A , w _2B and rib 1
the magnitude relationship between the thickness w ₂ of the minimum thickness of the r was investigated the influence of the junction quality. The results of the investigation are shown in Table 4 below.

[0029]

[Table 4]

The following can be said from Table 4 above. (1) 6N01-T5 material (proof stress σ _0.2 = 225 N / mm ² )
In the thickness w ₂ of the minimum thickness portion of the ribs in case of 1 mm, there was no occurrence of defects in the joint portion. At this time, w ₂ > w _2B and w ₂ > w _2A in any case where the height H of the extruded profile was 50 to 400 mm. (2) When the same material as in the above item (1) is used and the thickness w ₂ of the minimum thickness portion of the rib is 0.75 mm, w ₂ > w in all cases.
The condition of _2B was satisfied. When the height H of the extruded profile was 100 mm, that is, when w ₂ > w _2A, no joint defect occurred. Extruded profile height H = 200m
In the case of m, that is, when w ₂ = w _2A , a defect occurred to such an extent that it could not be visually identified. Extruded profile height H = 300mm
(W ₂ <w _2A ), a heavy defect occurs and the rib height H = 4
When the thickness was 00 mm (w ₂ << w _2A ), joining was impossible. (3) In 6N01-T1 material (proof stress ^{_{σ 0.2 = 90N / mm 2)}} , the thickness w ₂ of the minimum thickness portion of the ribs in case of 1 mm, the height H of the extrusions even when a 100mm or less, the junction A defect has occurred. At this time, w ₂ > w _2A , but w ₂ <w
_2B . (4) With the same material as in (3) above, when the thickness w ₂ of the minimum thickness portion of the rib is increased to 1.5 mm, w ₂ > W _2B , and
w _2> becomes w _2A, healthy joints without defects was obtained.

5. In the same two materials as Example 5 Example 4, a rectangular cross-section hollow extruded shape member of the shape and dimensions as shown in the same FIG. 5 as in Example 4, in each of the material between the outer surface of the rib 1 _r They were butted and contacted, and friction stir welding was performed in the longitudinal direction (the direction perpendicular to the paper surface of FIG. 5). At this time, the joint depth h =
4mm, shortest distance w between the outer surface of the stirring pin and the inner peripheral surface of the rib
The vertical height H of the extruded profile is varied stepwise between 50 and 400 _mm under the constant conditions of ₁ = 5 _mm , probe bottom diameter D = 15 _mm , probe pressing force F = 400 kgf. Te, the formula 1 with the deformation and buckling limit thickness w _2A changing the deformation and buckling limit thickness w _2B of the formula 2, the minimum thickness portion of these variations and buckling limit thickness w _2A, w _2B rib 1r Thickness w ₂
The effect of the size relationship on the joint quality was investigated. The results of the investigation are shown in Table 5 below.

[0032]

[Table 5]

The following can be said from Table 5 above. (1) 6N01-T5 material (proof stress σ _0.2 = 225 N / mm ² )
In the case the thickness w ₂ of the minimum thickness of the ribs is 1 mm, the height H of the extruded material is in the case of 50~300mm was not the occurrence of defects 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 >
_w2B . However, the height of the extruded material H = 400 mm
In the case of (w ₂ ≒ w _2A , and w ₂ > w _2B ), a defect which cannot be visually discriminated occurred at the joint. (2) above (1) and of the same material, if the thickness w ₂ of the minimum thickness of the ribs is 0.75 mm, in the case of all w _2> w _2B
That was the condition. And the height H of the extruded profile
Was less than 100 mm, that is, when w ₂ > w _2A, no joint defect occurred. Extruded profile height H = 200-3
In the case of 00 mm, that is, when w ₂ <w _2A , a joint defect occurred. Extruded profile height H = 400 mm (w ₂ << w _2A )
Could not be joined. (3) In the 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 when the height H of the extruded profile is 50 mm, the joint defect is not generated. 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 with the same material as in (3) above, w ₂ > w _2A and w ₂ = w _2B , and cannot be visually discriminated. A joint defect 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 in (3) above, w ₂ > w _2A and w ₂ > w _2B , resulting in a sound without defects. A good joint was obtained.

The findings from Table 4 in Example 4 and Table 5 in Example 5 are summarized as follows. (1) Even when the thickness w ₂ (mm) of the minimum thickness portion of the rib of the extruded aluminum-based material is equal to or greater than the first deformation / buckling limit thickness w _2A (mm) defined by the above-mentioned formula 1, When the thickness is smaller than the second deformation / buckling limit thickness w _2B (mm) defined by the equation 2, a joint defect occurs or the joint becomes impossible, and w ₂ (m
When m) is equal to w _2B (mm), a defect that cannot be visually recognized is generated. For this reason, 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 equal to the first buckling limit thickness w defined by the above equation (1).
If _2A less than joint defect occurs, w ₂ is the w
When it is equal to _2A , a defect that cannot be visually identified is generated. For this reason, 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.

Accordingly, the shortest distance w ₁ between the outer surface of the stirring pin and the inner peripheral surface of the rib is maintained at 0.6 mm or more, assuming that the occurrence of a defect that cannot be visually recognized in the friction stir welding portion is allowed. In addition, the aluminum-based extruded section for friction stir welding is formed in advance so that the thickness w ₂ (mm) of the minimum thickness portion of the rib forming the butted portion satisfies the following formulas 1 and 2. Is desirable. _{= w 2 ≧ w 2A {(} F × H) / (1439 × D)} 3/2 / 2 ──── Formula _{1 w 2 ≧ w 2B = F} / (2 × D × σ 0.2) ──── Equation 2 Here, w _2A : first deformation / buckling limit thickness (mm) w _2B : second deformation / buckling limit thickness (mm) F: probe pressing force (kgf) D: lower end of probe Diameter (mm) σ _0.2 ; Strength of extruded aluminum material (kgf / mm ² ) H; Vertical height of extruded material (vertical height of butt) (m
m)

Further, when the friction stir welding section is used for severe applications in which the generation of defects that cannot be visually discriminated is unacceptable, while maintaining the shortest distance w ₁ at 1.2 mm or more, It is preferable to form an aluminum-based extruded profile for friction stir welding in advance such that the thickness w ₂ (mm) of the minimum thickness portion of the rib forming the following satisfies the following formulas 1 ′ and 2 ′. w ₂ > w _2A = {(F × H) / (1439 × D)} ^3/2 / 2 {Formula 1 ′ w ₂ > w _2B = F / (2 × D × σ _0.2 )} Formula 2 '

It is considered that a 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 occurs as follows. That is, (1) the thickness w ₂ of the minimum thickness portion of the rib is such that the ribs opposed to the pressing force F (kgf) of the probe 3 deflect as shown in FIG. Alternatively, when the deformation or buckling limit thickness that does not cause buckling is less than w _2A given by the above formula 1 and w _2B given by the above formula 2, the outer surfaces are separated from each other as shown in FIG. Is deformed and buckled such that a gap 2g is formed between the ribs 1ar and 1br that contact each other, and the resulting gap 2g extends to the upper joint portion of the extruded sections 1a and 1b to be joined and is continuous in the joining direction. In such a case, a cavity defect may occur, or in a severe case, it may not be possible to join. (2) The thickness w ₂ of the minimum thickness portion of the ribs, the sufficiently larger than one value of w _2A and w _2B, when approximately equal to the other one of the values, the deformation and the The degree of buckling is not too great, and the resulting gap 2g can be relatively narrow, and the to-be-joined section 1a of this gap 2g
If the effect of the first and second parts on the upper joint is not so large, it is considered that a defect that cannot be visually identified can be generated.

Although the embodiments of the present invention have been described based on specific embodiments, the present invention is not limited to these embodiments, and other embodiments may be implemented without departing from the spirit of the invention. It does not need to be construed that the invention also includes the embodiment described above. For example, in the above-described embodiment, a specific material of an aluminum alloy extruded shape was used, and the test material mainly including a hollow shape having a rectangular cross section was described. It can also be applied to the butt friction stir welding method in which the outer surfaces of ribs of aluminum-based extruded profiles of hollow, C-shaped or L-shaped cross-sections other than square cross-sections are butt-contacted. Also, the present invention can be applied to an aluminum-based extruded member used for such friction stir welding.

[0039]

The present invention has the following excellent effects. According to the friction stir welding method for an aluminum-based extruded profile of the present invention and the aluminum extruded profile for friction-stir-welding of the present invention , the butt joints are used in the butt joining of the outer surfaces of the ribs. As a result of allowing hollow defects at the bottom of the joint that cannot be visually discriminated due to small deformation of the upper rib, the quality of the friction stir joint that can sufficiently cope with applications where the joint strength is not so strictly required is obtained. (2) According to the method of friction stir welding of an aluminum extruded profile of the present invention and the aluminum extruded profile of friction stir welding of the present invention , the upper portion of the butt portion is butt-jointed when the outer surfaces of the ribs are butted together. The occurrence of hollow defects at the bottom of the joint due to the deformation of the ribs can be prevented, and the quality of the friction stir welded portion can be obtained that can sufficiently cope with applications requiring relatively strict joint strength. (3) According to the extruded aluminum-based material of the present invention , at the time of butt friction stir welding in which the outer surfaces of the ribs are butted against each other, the occurrence of hollow defects at the bottom of the joint due to deformation of the ribs at the top of the butt is suppressed. A gap is created between the outer surfaces of both ribs due to deformation and buckling of the minimum thickness portion of the rib, and the influence of the gap extends to the joint at the upper part of the butt portion. It is possible to suppress and prevent the hollow defects that occur. Therefore, friction stir welding conditions are determined in advance, and when designing and manufacturing an aluminum-based extruded section to be subjected to friction stir welding under such conditions, the distance between the outer surface of the stirring pin of the probe for friction stir welding and the inner peripheral surface of the rib is determined. Shortest distance w ₁ (mm) and thickness w ₂ (mm) of the minimum thickness of the rib
Is set appropriately according to the required level of joint quality, the quality of friction stir welded joints, which can sufficiently cope with applications where joint strength is not so demanding, and the joint strength can be compared It is possible to selectively obtain the quality of a friction stir welded portion that can sufficiently cope with applications that are strictly required.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating parameters of a cross-sectional dimension of a probe for friction stir welding used in Embodiment 1 of the present invention, a cross-sectional dimension of an extruded member using the probe, and a radius of curvature of a rib inner peripheral surface.
FIG. 4 is a cross-sectional view showing a relationship between a welding depth h at the time of friction stir welding and a shortest distance w ₁ between a tip of an outer peripheral surface of a stirring pin and an inner peripheral surface of a rib.

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

FIG. 4 is a cross-sectional view showing a mechanism of occurrence of a hollow defect at the bottom of a joint caused by deformation of a rib at an upper portion of a butted portion of an aluminum-based extruded profile.

FIG. 5 is a sectional view defining and showing the sectional dimensions of the extruded profile used in Examples 4 and 5 of the present invention.

FIG. 6 is a cross-sectional view showing a mechanism of occurrence of a joint defect caused by deformation and buckling of a minimum thickness portion of a rib of an aluminum-based extruded profile.

[Explanation of symbols]

 1, 1a, 1b Extruded profile 1r, 1ar, 1br Rib 1as, 1bs Rib inner peripheral surface 2 Butt 2g Gap 3 Probe 4 Stirring pin 5 Joint

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-11-58036 (JP, A) JP-A-10-328856 (JP, A) JP-A 10-286682 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B23K 20/12

Claims (3)

(57) [Claims] 1. A stirrer comprising: a probe having a stirrer pin formed by abutting outer surfaces of ribs of an extruded aluminum material with each other to form a butted portion and projecting downward from a central portion of a concave or flat circular bottom surface. While rotating and pushing the pin into the upper part of the extruded profile of the butted portion, pressing the concave or flat circular bottom surface against the upper surface of the extruded profile near the butted portion, rotating the probe into the butted line. In the method of friction stir welding of an aluminum-based extruded profile for joining the extruded profile upper part of the butt portion by moving along the outer surface of the agitating pin pushed into the extruded profile upper part of the butt portion the shortest distance w ₁ is kept above 0.6 mm, the friction stir welding while cooling ribs inner peripheral surface of the extruded shape member between the ribs in the peripheral surface of the push Degata material and
Performing friction stir welding of an aluminum extruded profile. 2. The stirrer according to claim 1, wherein the stirrer includes a stirrer pin formed by abutting the outer surfaces of the ribs of the extruded aluminum-based member with each other to form a butted portion and projecting downward from the center of the concave or flat circular bottom surface. While rotating and pushing the pin into the upper part of the extruded profile of the butted portion, pressing the concave or flat circular bottom surface against the upper surface of the extruded profile near the butted portion, rotating the probe into the butted line. By moving along the extruded section of the butt portion, the aluminum-based extruded section for friction stir welding for friction stir welding of the upper section of the extruded section, at a predetermined joining depth h of the upper section of the extruded section of the butt section, preformed of a shortest distance w ₁ so as to keep the above 0.6mm between the ribs in the peripheral surface of the outer surface and the push Degata material of the stirring pin is pushed into the extruded profile over the abutting portion
Of the minimum thickness of the extruded profile ribs forming the butted portion.
The thickness w ₂ is set so as to satisfy the following equations (1) and (2).
An aluminum-based extruded section for friction stir welding, characterized in that it is formed . w ₂ ≧ w _2A = {(F × H) / (1439 × D)} ^3/2 / 2 Formula 1 w ₂ ≧ w _2B = F / (2 × D × σ _0.2 ) here equation 2, w _2A: first deformation and buckling limit thickness (mm) w _2B: second deformation and buckling limit thickness (mm) F; pressing force of the probe (kgf) D; probe lower end Diameter (mm) σ _0.2 ; Strength of extruded aluminum material (kgf / mm ² ) H; Vertical height of extruded material (vertical height of butt) (mm) 3. A method according to claim 1, wherein a predetermined joining depth h at an upper part of the extruded profile of the butted portion is between an outer surface of the stirring pin pushed into the extruded profile and an inner peripheral surface of a rib of the extruded profile. friction stir welding aluminum-based extruded profile of claim 2, characterized in that, which is previously formed so as to keep the shortest distance w ₁ than 1.2 mm.