JP3297845B2 - Aluminum member joining method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for joining aluminum members, and more particularly to a method for joining aluminum members by friction stir welding.

[0002]

2. Description of the Related Art In recent years, there has been a strong demand for weight reduction of transport equipment from the viewpoint of environmental protection, and therefore aluminum has been increasingly used. For example, as one of measures for reducing the weight of automobiles, a space frame structure in which an aluminum alloy profile is formed and assembled to stretch a body panel is proposed.

[0003] In this method, a shape is formed by bending or the like and joined, and the joining is usually performed by MIG or TIG.
Arc welding has been applied. However, when a 6000 series aluminum alloy, which is frequently used for transportation equipment, is subjected to arc welding, there is a problem that the heat input during welding softens the heat affected zone by welding and the strength of the profile is greatly reduced.

[0004] Similar problems have arisen in vehicles other than automobiles since 6000 series aluminum alloys are often used. Further, in arc welding, distortion due to heat input tends to increase, and distortion correction is often required as a post-process, and improvement is desired.

[0005] In particular, an aluminum honeycomb panel in which aluminum face plates are brazed and joined to both surfaces of an aluminum honeycomb core has attracted attention as a component of a high-speed vehicle structure. When connecting honeycomb panels by arc welding of materials, there is a problem that the welded part is deformed due to thermal distortion and removal of excess metal and the appearance of the vehicle is damaged, and blow holes and solidification cracks peculiar to arc welding Such defects often occur, and a large number of man-hours are required for rework, and the appearance is further impaired. 6 as shape material
When the 000 series alloy is used, there is also a disadvantage that the heat input during welding is softened by the heat input during welding as described above, and the strength of the profile is greatly reduced.

[0006] Friction welding, laser welding, mechanical joining, bonding and the like are also known as joining methods of aluminum instead of inert gas welding such as TIG and MIG, but they are applicable in terms of workability, reliability or cost. Limited. Of these, friction welding involves rotating the materials to be joined at relatively high speeds and rubbing them together, and when the joints become hot due to frictional heat, presses the materials to stop rotation and joins the materials. Recently, a technique has been developed in which friction welding is applied to joining of butt portions.

In this method, a material to be joined is butt-constrained on a hard backing, and a hard non-consumable pin type probe is pressed against the butt while rotating at a high speed, and the butt is caused by frictional heat. As plasticity is possible, a pin-type probe is inserted into a butt portion and moved along the butt portion while rotating at high speed, which is also called friction stir welding. (U.S. Patent No. 5,460,317, Japanese Patent Application Laid-Open No. 7-505090, Japanese Patent Application No. 9-508073, etc.)

According to the friction stir welding, since the welded portion does not melt, a decrease in strength of the welded portion is small, a problem of a surface state such as an oxide film can be avoided, a flat welded surface can be obtained, and the depth of the welded portion can be reduced. There are excellent advantages such as controllability. On the other hand, since a hard backing is required in the joining operation, there is a problem when joining a hollow material or the like whose backing cannot be removed after joining.

For example, as shown in FIG. 8, an aluminum honeycomb panel HP obtained by joining an aluminum face plate P to both surfaces of an aluminum honeycomb core HC by brazing or the like is disposed at an end of the honeycomb panel HP. When joining through a frame member F made of extruded aluminum material, the frame members F are joined so as to form a square shape,
A pair of wedge-shaped steel jigs S ₁ and S ₂ as shown in FIG. 9 are inserted into the square-shaped opening of the butted portion, and these are used as a backing. It has also been proposed to perform friction stir welding using the probe 3 provided with the pin 5 to form a joint W, and then pull out the wedge-shaped steel jigs S ₁ and S ₂ .

However, in this method, adjustment for inserting the wedge-shaped steel jig and pressing it against the frame material is not always easy, and there are many cases where a sound joint cannot be obtained. Wedge-shaped steel jigs are heavy and difficult to handle. The joining operation process is troublesome because it involves insertion and removal of the jig. If the square-shaped opening is small, there are many problems such as difficulty in inserting the jig.

[0011]

SUMMARY OF THE INVENTION The present invention relates to a method of frictionally joining aluminum (including an aluminum alloy, the same applies hereinafter) members by butt-bonding, particularly to aluminum members, such as hollow materials, whose backing cannot be removed after joining. The purpose of the present invention is to solve the conventional problems in the case of the stir welding, and the purpose is to leave a backing that has been friction stir welded together with the joining portion inside the aluminum member to join hollow materials and the like. It is an object of the present invention to provide a method for joining aluminum members, which enables the formation of a joint with reduced strength reduction and without deformation of the joint due to thermal strain or excess.

[0012]

According to a first aspect of the present invention, there is provided a method of joining aluminum members, the method comprising joining aluminum hollow members in a longitudinal direction by butt joining. Inside the butted part of
Along the inner peripheral surface of the butting portion, the inner peripheral surface is 0.5 mm
A backing made of the same material as the hollow member having the following gap and having a tapered taper in the longitudinal direction of the hollow member from the butt portion is provided, and the butt portion is friction stir welded together with the backing. It is characterized by.

According to a second aspect of the present invention, there is provided a method of joining aluminum members by butt-joining the aluminum tubular members so as to form a cross joint with the aluminum tubular members. The second square tubular member abuts on the inner surface of the second square tubular member at the abutting portion, the inner circumferential surface of the abutting portion has a gap of 0.5 mm or less, and A backing made of the same material as that of the square tubular member having a tapered taper toward the square tubular member is provided, and the contact portion is friction stir welded together with the backing.

According to a third aspect of the present invention, there is provided a method for bonding an aluminum member according to the second aspect, wherein the second square tubular member is brought into contact with the side surface of the first square tubular member, and the side surface of the first square tubular member is connected to the second square tubular member. A triangular prism member is fitted to a corner formed by the square tubular member, and the corner is friction stir welded together with the triangular prism member.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a shape member having an opening which is continuous in the longitudinal direction when an aluminum member is joined to a hollow member such as a hollow tube or a hollow shape in the longitudinal direction. It is suitably used when butt-joining shaped members in the longitudinal direction. In the method in which the hollow members are butt-joined in the longitudinal direction, a backing made of the same material as that of the hollow members is provided inside the butt portion of the hollow member along the inner peripheral surface of the butt portion.

[0016] When joining a hollow tube of aluminum in the longitudinal direction, as shown in FIG. 1, the interior of the hollow tube T ₁ and hollow tube butt section 1 of T _2, the hollow tube T ₁ , disposing the backing 2 of the same material as the T _2. For example, the backing 2 is formed into an annular shape from an extruded material, a drawn material, or a rolled material. The gap c between the inner surfaces of the hollow tubes T ₁ and T ₂ of the butting portion 1 and the backing is preferably 0.5 mm or less, and the gap c is 0.5 m or less.
If it exceeds m, defects such as formation of a tunnel-like hole at the junction are likely to occur. The backing 2 is preferably provided with a slight taper T as shown in FIG.

The friction stir welding of the butting portion 1 is performed by rotating a non-consumable steel probe 3 composed of a rotating cylindrical body 4 and a pin 5 provided at the tip of the rotating cylindrical body 4 at a high speed. This is performed by inserting the pin 5 into 2 and moving it horizontally along the butting portion 1 while rotating at high speed, and joining the butting portion 1 together with the backing 2. Pin 5
Is preferably 1 t to 2 t with respect to the thickness t of the hollow tube, and the width of the backing 2 is preferably 1 t to 5 t.

When joining aluminum hollow rectangular sections in the longitudinal direction, as in the case of joining hollow tubes, as shown in FIG. 2, butted portions of hollow sections E ₁ and E ₂ to be joined are used. Inside ₁ , a backing 2 made of the same material as the hollow members E ₁ and E ₂ is provided. Hollow sections E ₁ , E _{2 of} butt ₁
It is preferable that the gap (not shown in FIG. 2) between the inner surface and the backing 2 is 0.5 mm or less, as in the case of joining the hollow tubes. The backing 2 is preferably provided with a slight taper T as shown in FIG.

The friction stir welding of the butting portion 1 is performed in the same manner as in FIG. Before joining, the tabs 6, 6 are arranged on the side surfaces of the hollow section of the butted portion so that the joining start end and the end end do not remain at the joining portion W, and the start end and the end end of the friction stir welding are the tab materials. 6, so that it is on 6.

An embodiment in which the aluminum member is a square tubular member and the square tubular members are butt-joined to form an intersecting joint will be described. As shown in FIG. The second square tubular members E ₆ , E ₇ abut against the side surface of the _fifth member ₅ , and a backing 2 made of the same material as the square tubular member is provided inside the second square tubular members E ₆ , E _{7 at} the contact portions 7, 7. 2 and the contact portion 7 is friction stir welded together with the backing 2 to form a joint W.

As shown in FIG. 4, the first square tubular member E ₅
The second rectangular tubular members E ₆ and E ₇ are in contact with the side surfaces of the first rectangular tubular member E ₅ , and a triangular prism is formed at the corner formed by the side surface of the first rectangular tubular member E ₅ and the second rectangular tubular members E ₆ and E _7. The member 8 is fitted, and FIG.
As shown in FIG. 7, a step of friction stir welding the corners together with the triangular prism member 8 can be used together. The triangular prism member 8 can also serve as a tab material for locating the start end and the end end of the friction stir welding. As shown in FIG. 6, the upper end of the triangular prism member 7 may be used as a tab material, and the upper end may be cut off after joining.

[0022]

Hereinafter, examples of the present invention will be described in comparison with comparative examples. Example 1 2024 alloy pipe (T6) having an outer diameter of 400 mm and a thickness of 5 mm
As shown in FIG. 1, a 20 mm wide backing 2 made of the same material and having a taper of 1/50 is applied to the butt portion of the butt material 1 by 10 mm on both sides of the butt portion 1 to form a gap c. It was inserted so as to be 0.1 mm or less and fixed.

A steel probe having a pin length of 6.5 mm, a pin diameter of 6 mm, and a rotating cylindrical body diameter of 16 mm is inserted into the butt while rotating at 1500 rpm, and the tube is rotated at a speed of 300 mm / min to pull out the pin. As a result, a smooth joint without excess was formed. The hardness of the joint was 75% of the base metal at the portion where the softening was the largest.

EXAMPLE 2 As shown in FIG. 2, a 1/50 taper was provided at the abutting portion of a 6N01 square hollow member (T5 material) having a length of 20 mm, a width of 30 mm and a thickness of 2.5 mm. A backing 2 having a width of 10 mm is inserted into the shape material on both sides of the butting portion 5 by 5 mm and the gap c is 0.1 mm or less, and the same material as the shape material is formed on both sides of the butting portion 1. 15mm x 15mm
A × 20 mm tab material was provided, and these were fixed on a steel base.

While rotating a steel probe having a pin length of 4 mm, a pin diameter of 4 mm, and a rotating cylindrical body diameter of 10 mm at 3500 rpm, insert the pin until the rotating cylindrical body hits the tab material, and move up to 500 mm / mm to the opposite tab material. When it was moved horizontally at the speed of one minute and pulled out, a smooth joint without any excess was formed. The hardness of the joint was 75% of the base metal at the portion where the softening was the largest. The tab material was easily removed by folding after joining.

Comparative Example 1 Friction stir welding was performed in the same manner as in Example 1 except that the gap c was changed to 0.6 mm. Tunnel-like defects having a width of 0.5 mm or more in the longitudinal direction of the joint were found. occured.

Comparative Example 2 In Example 2, friction stir welding was performed in the same manner as in Example 2 except that the gap c was changed to 0.7 mm, and a tunnel-like defect having a width of 0.5 mm or more in the longitudinal direction of the joint was found. occured.

EXAMPLE 3 As shown in FIG. 3, a rectangular hollow material of the same material and dimensions as shown in FIG. 3 was placed on the side of a 6N01 alloy (T5 material) rectangular hollow material having a length of 25 mm, a width of 30 mm and a thickness of 2.5 mm. 2) having a 1/100 taper inside the hollow profile at the abutting part
A backing 2 of 0 mm × 25 mm × 5 mm was provided, and a tab material 6 of 6N01 alloy (T5 material) was arranged and fixed at a corner.

A steel probe having a pin length of 3.5 mm, a pin diameter of 3 mm, and a rotating cylindrical body diameter of 10 mm was inserted into the tab material while rotating at 1500 rpm, and was horizontally moved at a feed speed of 300 mm / min. When a line extending from the surface to the backing side by 1 mm was joined and pulled out to the opposing tab material, a smooth joint without excess was formed. Observation of the cross section of the joint showed no defect. After joining, the tab material could be easily removed.

EXAMPLE 4 As shown in FIG. 4, a rectangular hollow material of the same material and dimensions as shown in FIG. 4 was placed on the side of a 6N01 alloy (T5 material) rectangular hollow material having a length of 25 mm, a width of 30 mm and a thickness of 2.5 mm. 2) having a 1/100 taper inside the hollow profile at the abutting part
A backing 2 of 0 mm × 25 mm × 5 mm was provided, and a triangular prism-shaped member 8 of 6082 alloy (T1 material) was arranged and fixed at a corner.

A steel probe having a pin length of 3.5 mm, a pin diameter of 3 mm, and a rotating cylindrical body diameter of 10 mm is inserted into the tab material while rotating at 1500 rpm, and is horizontally moved at a feed speed of 300 mm / min. When a line extending from the surface to the backing side by 1 mm was joined and pulled out to the opposing tab material, a smooth joint without excess was formed. Observation of the cross section of the joint showed no defect. Further, the corner portion is pin-length 7 m from above the triangular prism-shaped member 8.
m, pin width 5 mm, rotating cylinder body diameter 10 mm, rotation speed 1500 rpm, feed speed 300 m
When bonding was performed under the condition of m / min, a sound bonded portion was obtained.

Comparative Example 3 In Example 4, friction stir welding was carried out without using a backing.
A tunnel-like defect having a width of 0.5 mm or more occurred at the joint.

Example 5 As shown in FIG. 7, a face plate of a 6951 alloy having a thickness of 1 mm,
A core of 6951 alloy having a thickness of 0.3 mm and a cell size of 20 mm, a height of 28 mm, a width of 44 mm, and a thickness of 2.5 mm 6
A brazed honeycomb panel (width 1000 mm, length 300
0 mm) H ₃ and H ₄ are juxtaposed in the width direction,
20 were abutted and fixed on a steel platen. As can be seen in FIG.
The ends of the buttings are in a form in which the openings 21, 21 of the square hollow members 20, 20 abut.

A backing 2 (width 10 mm) of a 6N01 alloy having a taper T of 1/50 at the end of the butted portion at the back side of the butted portion is joined to the butted hollow-shaped hollow material 2.
The mounting was performed so that the gap c was 0 mm or less and the gap c was 0.1 mm or less.

The pin length is 3.5 mm, the pin diameter is 3.5 mm,
A probe with a rotating cylindrical body diameter of 12 mm was rotated at 1500 r.
Insert the pin into the butt while rotating at
It was moved horizontally at a speed of mm / min to perform friction stir welding.
As a result, a smooth and healthy joint without any excess was formed.

[0036]

According to the present invention, it is possible to obtain a joint having a small reduction in strength of the joint and a small amount of distortion without distortion, which can be effectively applied to joining of a space frame for an automobile and a vehicle structure. Significant weight reduction is possible.

[Brief description of the drawings]

FIG. 1 is a partial perspective view showing a case where the present invention is applied to joining of a pipe material.

FIG. 2 is a partial perspective view showing a case where the present invention is applied to joining of an extruded hollow material.

FIG. 3 is a partial perspective view showing a case where the present invention is applied to manufacturing of a cross joint of a hollow profile.

FIG. 4 is a partial perspective view showing another embodiment of FIG. 3;

FIG. 5 is a partial cross-sectional view showing the joining of the triangular prism members arranged at the corners in FIG.

FIG. 6 is a partial perspective view showing another embodiment of the joining of the triangular prism-shaped members arranged at the corners in FIG.

FIG. 7 is an explanatory view showing still another embodiment in the case where the present invention is applied to the joining of aluminum honeycomb panels.

FIG. 8 is a partial cross-sectional perspective view showing a conventional example in which aluminum honeycomb panels are joined by friction stir welding.

FIG. 9 is a perspective view showing a wedge-shaped steel jig inserted into the butting opening in FIG. 8;

[Explanation of symbols]

1 butt section 2 backing 3 probe 4 rotating cylinder 5 pin 6 tab member 7 abutting portion 8 triangular prism member 19 hollow member 20 hollow shape member 21 opening H ₄ honeycomb panel H ₅ honeycomb panel T tapered c gap W junction HC Honeycomb core HP Honeycomb panel P Face plate F Frame S ₁ Wedge-shaped steel jig S ₂ Wedge-shaped steel jig

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-9-309164 (JP, A) JP-A-10-76375 (JP, A) JP-A-11-192564 (JP, A) JP-A-11-192 47957 (JP, A) JP 10-52772 (JP, A) U.S. Pat. TWI, February 13, 1995, Vol. 63, No. 1, p. 13-14, 16, NDL accepted on February 13, 1995 (58) Field surveyed (Int. Cl. ⁷ , DB name) B23K 20/12

Claims (3)

(57) [Claims] 1. A method for joining aluminum hollow members in the longitudinal direction by butt joining, wherein an inner peripheral surface of the hollow member is connected to the inner peripheral surface along the inner peripheral surface of the butt portion. A backing made of the same material as that of the hollow member having a gap of 0.5 mm or less and having a taper from the abutting portion toward the longitudinal direction of the hollow member is provided, and the abutting portion is friction stir welded together with the backing. A method for joining aluminum members. 2. A method for butt-joining aluminum tubular members to form an intersecting joint with the aluminum tubular members, wherein a second square tubular member is applied to a side surface of the first square tubular member. In contact with the inside of the second square tubular member at the contact portion, the inner circumferential surface of the contact portion has a gap of 0.5 mm or less, and a taper that tapers from the contact portion toward the second square tubular member. A method for joining aluminum members, comprising: providing a backing made of the same material as that of the square tubular member provided with the backing; 3. A second rectangular tubular member abuts on a side surface of the first rectangular tubular member, and a triangular prism member is formed on a corner formed by the side surface of the first rectangular tubular member and the second rectangular tubular member. And fit
3. The method for joining aluminum members according to claim 2, wherein the corner portions are friction stir welded together with the triangular prism members.