JP3948323B2 - Method of joining aluminum or aluminum alloy sheet - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a joining method in which a pair of aluminum or aluminum alloy (hereinafter simply referred to as aluminum alloy) plate materials having different plate thicknesses, and particularly, a rolled and formed plate material are joined in a butt state along respective end surfaces.
[0002]
[Prior art]
In recent years, friction stir welding that can easily join metal materials to each other as compared with arc welding or the like has attracted attention. In this friction stir welding, as shown in FIGS. 8A and 8B, a tool 22 that rotates along a butt surface between a pair of aluminum alloy plate materials 20 and 21 whose end surfaces butt and restrain each other. It is given by moving while pressing. The tool 22 is made of a material having a higher hardness and softening temperature than the material to be joined, a rotating cylindrical bobbin 24, a surface restraining portion 26 that is a concave bottom surface, and a friction pin 28 that hangs coaxially from the center thereof. Consists of.
[0003]
Then, as shown in FIG. 8B, the tool 22 is moved in the horizontal (left) direction while being slightly inclined along the abutting surface, and a vertical pushing force is applied. On the peripheral surface of the friction pin 28, a screw-like friction stirrer blade is formed along a horizontal direction (not shown) to facilitate generation of frictional heat and stirring of the softened material.
In addition, the length of the friction part of the normal friction pin 28 is 3 to 10 mm, its diameter is 3 to 10 mm, and the diameter of the surface restraining part 26 is 6 to 25 mm. Further, in this case, the rotational speed of the tool 22 is 500 to 15000 rpm, the feed speed is 0.05 to 2 m / min, and the axial pushing force applied to the tool 22 is within the range of 1 kN to 20 kN, and the thickness of the plate to be joined It is selected according to the material.
[0004]
As the friction pin 28 rotates and moves, the aluminum alloy in the vicinity of the abutting surfaces of the plate members 20 and 21 is heated and plasticized by frictional heat, and the plate members 20 and 21 are sandwiched between the abutting surfaces. In between, it is fluidized and stirred in the horizontal and vertical directions. In addition, the surface restraining portion 26 suppresses the vertical movement of the fluidized aluminum alloy to generate frictional heat, and stirs the fluidized aluminum alloy by the surface restraining portion 26 and the friction pin 28. As a result, as shown in FIG. 8C, the aluminum alloy is solidified to form a joining line W having a certain width and depth. Therefore, there is no raised welding beat like arc welding, and post-processing becomes easy.
[0005]
[Problems to be Solved by the Invention]
However, due to the stirring of the fluidized aluminum alloy and the pressing of the surface restraining portion 26, the plate thickness in the vicinity of the joint portion of the plate members 20 and 21 is reduced, and as shown in FIG. A concave groove Wa is formed. There is a problem that the bonding strength between at least the pair of plate members 20 and 21 is reduced by the depth d of the concave groove Wa. The problem of the concave groove Wa becomes more conspicuous as the thickness of the aluminum alloy sheet becomes thinner. That is, when thick plate members are joined together, the depth of the recessed groove Wa formed even if the joining line W is formed deeply does not change so much, so that the required joining strength can be maintained. Further, the pair of protrusions We formed at both ends of the surface of the concave groove Wa are burrs protruding from the surface SF of the plate members 20 and 21 as a result of frictional stirring, and this may not be formed.
[0006]
On the other hand, as shown in FIG. 8D, when joining a pair of extruded profiles 30, 31 of aluminum alloy, it corresponds to the depth d of the groove Wa along the end faces of the profiles 30, 31. The ridges 32, 32 having thick portions can be integrally formed in advance.
Therefore, when a deep joining line W is formed by friction stir welding between the end faces of the respective shapes 30 and 31, as shown in FIG. It is possible to absorb the thickness reduction corresponding to the depth d of the groove Wa.
However, in the case where it is difficult to integrally form the ridges 32 with the extruded shape member 30 or the like, such as when the member to be joined is a rolled molded material, it is shown in FIGS. 8D and 8E. A joining method cannot be applied, and friction stir welding between plate members having different plate thicknesses has never been known so far.
The present invention solves the problems in the prior art described above, does not cause a reduction in the plate thickness at the joint, while maintaining the required strength between relatively thin aluminum alloy plate materials having different plate thicknesses, It is an object of the present invention to provide a method for joining aluminum alloy sheets that can be reliably and easily subjected to friction stir welding.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention sandwiches a vertical piece of a bonding material having a substantially T-shaped cross section between the end surfaces of a pair of aluminum alloy plate materials, and contacts the horizontal piece of the bonding material to the surface of each plate material. Thus, the idea is to compensate for the plate thickness of each plate material by simultaneously performing friction stir welding of the three members of the pair of plate material and the bonding material.
[0008]
That is, according to the method for joining aluminum or aluminum alloy sheets of the present invention (Claim 1), a vertical piece of joining material having a substantially T-shaped cross section is sandwiched between the end faces of a pair of aluminum or aluminum alloy sheets having different thicknesses. and a step of the bottom surface of the stepped in the horizontal strip of the joining material in contact with the front surface of the sheet from the surface side between the pair of aluminum or aluminum alloy sheet, the bonding material on the surface restraining portion of the bobbin bottom rotating Pressing the inclined upper surface of the horizontal piece, penetrating from the center of the surface holding part and rotating at the same time with the surface holding part, the friction pin passes through the horizontal piece of the bonding material, and between the vertical piece and the end faces of the plate members friction stir together to and enters a predetermined depth in oblique, it is moved along the longitudinal direction between the end surface of the plate member to each other while rotating the bobbin and friction pins to Includes a step of performing focus, and to form a joining line where the surface is inclined in the longitudinal direction between said pair of plate members,
It is characterized by that.
[0009]
According to this, by the horizontal piece of the joining material that is plasticized and fluidized together with a pair of plate materials having different thicknesses, it is possible to compensate for the reduction in the thickness of the joining portion straddling between the respective plate materials, and the thin wall by friction stir welding However, it is possible to reliably perform the butt joining between the plate members with the required strength. In addition, the bonding material can be fixed simply by sandwiching the vertical piece between the pair of plate members, and can be easily performed by a normal plate member restraining method.
[0010]
Furthermore , according to a pair of board | plate materials from which board thickness differs, the horizontal piece which has the inclined upper surface of a joining material can be arrange | positioned, and the board thickness reduction | decrease by friction stir welding can also be prevented effectively.
[0011]
Furthermore, the joining method (Claim 2 ) of the aluminum or aluminum alloy plate material in which the bobbin and the friction pin are used while being inclined so as to be orthogonal to the inclined upper surface of the horizontal piece of the joining material is also included.
According to this, it is possible to more reliably perform the friction stir welding while a pair of plate materials having different plate thicknesses are brought into contact with each other. The bobbin and the friction pin are included in a tool described later.
[0012]
In addition, the bonding material, the aluminum or the same or different composition of aluminum or an aluminum alloy extruded shape of aluminum alloy sheet, method of joining an aluminum alloy sheet (claim 3) are also included.
According to this, Ki de be subjected to friction stir welding more reliably, and for using the bonding material of the extruded profile, its preparation easy in extrusion molding, with the design of the cross-sectional shape is also easy, plate They can be positioned easily .
[0013]
DETAILED DESCRIPTION OF THE INVENTION
In the following, preferred embodiments of the present invention will be described with reference to the drawings.
FIGS. 1-6 is related with the friction stir welding method of the reference form used as the premise of this invention.
FIG. 1 (A) shows a cross section of a pair of aluminum alloy sheets 1a and 1b to be joined and a joining material 2 interposed therebetween. The aluminum alloys of the plate materials 1a and 1b include pure Al (for example, JIS: A1080, A1100), Al-Mn (for example, JIS: A3003), Al-Mg (for example, JIS: A5052, A5457), Al-Mg. -Si type (for example, JIS: A6061) or the like is used. The bonding material 2 has a substantially T-shaped cross section integrally including a horizontal piece 4 and a vertical piece 6 extending at a right angle from the center thereof, and is formed of an extruded shape made of an aluminum alloy. For the aluminum alloy of the shape member 2, for example, Al-Mg-Si JIS: A6061-T5, A6063-T5, T6, 6N01-T5, or the like is used. Any material may be used as the material of the plate materials 1a and 1b and the alloy composition of the bonding material 2, but an appropriate material may be selected in consideration of the strength after bonding. The plate thickness of the plate materials 1a and 1b is about 3 to 12 mm.
[0014]
First, as shown in FIGS. 1A and 1B, the vertical piece 6 of the bonding material 2 is inserted between the end surfaces of the pair of plate materials 1a and 1b, and the left and right halves of the horizontal piece 4 are respectively placed on the plate materials 1a and 1b. The plate members 1a and 1b are restrained by a jig (not shown) in a state where they are in contact with each of the surfaces. Thereby, the joining material 2 is fixed while the vertical piece 6 is sandwiched between the end faces of the plate materials 1a and 1b. In addition, the length of the vertical piece 6 in the bonding material 2 is the same as the plate thickness of the plate materials 1a and 1b.
Next, as shown in FIG. 1B, the friction stir welding tool 10 is brought close to the outside of the restrained plate members 1a and 1b and near the center of the horizontal piece 4 of the bonding material 2. The tool 10 has a cylindrical bobbin 12, a gently curving and concave surface restraining part 14 that forms the bottom surface thereof, and a friction pin 16 that hangs down coaxially with the bobbin 12 from the center thereof. A screw-shaped horizontal friction stirrer blade (not shown) is formed on the surface of the pin 16.
[0015]
In addition, the length of the friction pin 16 is 3 to 10 mm, the diameter is 2 to 10 mm, and the diameter of the surface holding portion 14 is 6 to 25 mm. The rotation speed of the tool 10 is 500 to 15000 rpm, the feed speed is 0.05 to 2 m / min, the pushing force applied in the axial direction of the tool 10 is about 1 kN to 20 kN, and the thickness, material, and dimensions of the bonding material Select an appropriate value according to the material.
Then, as shown in FIG. 1 (C), the friction pin 16 of the rotating tool 10 passes through the horizontal piece 4 of the bonding material 2 and enters the vicinity of the lower part of the vertical piece 6. At the same time, the surface holding portion 14 of the tool 10 presses the horizontal piece 4 of the bonding material 2 from above. In this state, by moving (feeding) the tool 10 toward the front in the drawing, the friction stir welding of the reference form can be performed.
[0016]
Here, the relationship between the plate materials 1a and 1b and the bonding material 2 will be described with reference to FIG.
The height f of the vertical piece 6 of the bonding material 2 is preferably the same as the thickness t of the plate materials 1a and 1b but slightly different. Thereby, the space between the end surfaces of the plate materials 1a and 1b is occupied by the vertical piece 6, and a healthy joining line W by the tool 10 described later can be formed in the entire cross section.
Further, the thickness g of the horizontal piece 4 of the bonding material 2 is preferably 0.2 to 1.0 times the plate thickness t of the plate materials 1a and 1b. As a result, the plate thickness in the vicinity of the end surfaces of the relatively thin plate materials 1a and 1b can be increased, and even when friction stir welding is performed, the strength is prevented from lowering and the required bonding strength can be easily obtained. If the thickness is less than 0.2 times, the plate thickness does not increase, and a portion thinner than the plate thickness t of the plate members 1a and 1b is formed in the bonded portion after bonding, so that the bonding strength may be insufficient. On the other hand, if it exceeds 1.0 times, the size of the bonding material 2 becomes large, the time required for the processing increases, and the friction pin 16 hardly enters between the end faces of the plate materials 1a and 1b.
[0017]
Further, the relationship between the bonding material 2 and the tool 10 will be described with reference to FIGS.
The width X of the horizontal piece 4 of the bonding material 2 is desirably 0.8 to 1.0 times the outer diameter P of the bobbin bottom surface 12 (that is, the diameter of the surface restraining portion 14) of the tool 10. Thereby, the surface restraining portion 14 on the bottom surface of the bobbin 12 can press the substantially entire horizontal piece 4 downward, and can prevent the plasticized and fluidized aluminum alloy from being scattered outside.
Further, the diameter p of the friction pin 16 in the tool 10 is desirably 1.2 times or more the thickness x of the vertical piece 6 of the bonding material 2. As a result, the friction pin 16 also enters the vicinity of the end face of the vertical piece 6 and the plate materials 1a and 2a on both sides thereof, and a joining line W having a sound stirring portion by plasticizing and fluidizing each aluminum alloy between these three members is formed. Can be formed. The upper limit of the diameter p is preferably about 2.0 times the thickness x.
Furthermore, the length S of the friction pin 16 is preferably 0.05 to 0.4 mm shorter than the sum of the thickness t of the plate material 1a (1b) and the thickness g of the horizontal piece 4 of the bonding material 2. . Thereby, the joining line W which has a healthy stirring part can be formed in the whole cross section of a junction part.
[0018]
FIG. 3 relates to a friction stir welding process which is a reference embodiment of the present invention.
FIG. 3A shows a state in which the tool 10 rotating at 500 to 15000 rpm is slightly inclined in the longitudinal direction of the joint portion with respect to the plate materials 1a and 1b in which the joint material 2 is fixed between the end faces. As shown in FIG. 3B, the tool 10 advances the tip of the friction pin 16 to the vicinity of the lower portion of the vertical piece 6 of the bonding material 2 and presses the surface holding portion 14 to the entire horizontal piece 4. The pushing force applied in the axial direction of the tool 10 at this time is about 1 kN to 20 kN. In this state, the tool 10 is sent to the left side in the figure. The feeding speed is 0.05 to 2 m / min.
Accordingly, as shown in FIG. 3C, the aluminum alloy of the horizontal and vertical pieces 4 and 6 of the joining material 2 and the vicinity of the end surfaces of the plate materials 1a and 1b as the friction pin 16 rotates and moves. Is plasticized by heating with frictional heat, and fluidized in the horizontal and vertical directions between the plate members 1a and 1b with the vertical piece 6 interposed therebetween. Further, the surface restraining portion 14 suppresses the vertical movement of the fluidized aluminum alloy and stirs the aluminum alloy fluidized by the friction pin 16.
[0019]
As a result, as shown in FIG. 3 (D), the aluminum alloy is solidified in the solid state, and a joining line W having a constant width and depth is formed in the trace that the tool 10 has passed. The On the surface of the joining line W, a very shallow groove Wa is formed at the center, and a pair of low protrusions Wb are formed on both sides thereof. Since both the concave groove Wa and the convex portion Wb are located outward from the respective surfaces of the plate members 1a and 1b, no thin portion is formed by the joining line W than the plate thickness of the plate members 1a and 1b. . Further, the bottom Wc of the joining line W reaches the back surface on the opposite side of each of the plate materials 1a and 1b. By forming such a joining line W, sound joining can be performed without reducing the joining strength between the plate members 1a and 1b. In addition, when each convex part Wb is excised to the position of the concave groove Wa, the appearance is also preferable. Moreover, in order to prevent the strength reduction of the joint portion, the dimensions of the joint material 2 may be set so that the minimum thickness of the joint portion is larger than the plate thickness of the plate materials 1a and 1b if there is no problem in appearance.
[0020]
FIG. 4A shows the friction stir welding under the condition that the width X of the horizontal piece 4 of the bonding material 2 fixed between the plate materials 1a and 1b is 1.0 times the outer diameter P of the bobbin 12 in the tool 10. The cross section of the joining line W obtained by this is shown. In this case, since the diameter p of the surface restraining portion 14 on the bottom surface of the bobbin 12 and the width X of the horizontal piece 4 are the same, as shown in the figure, convex portions protruding obliquely in a burr form on both sides of the surface of the joining line W. A pair of Wb is formed almost symmetrically. Therefore, it is necessary to cut each convex portion Wb to the position of the concave groove Wa.
FIG. 4B shows that the thickness t of the plate members 1a and 1b is set to a minimum of 3 mm, the thickness g of the horizontal piece 4 is 0.4 times between them, and the width X of the horizontal piece 4 is set to the bobbin 12. The cross section of the joining line W obtained by fixing the joining material 2 as 0.8 times the outer diameter P and performing friction stir welding is shown. In this case, the joining line W has a relatively flat cross-sectional shape, but the concave grooves Wa and the convex portions Wb on the surface thereof are both located outward from the surfaces of the plate members 1a and 1b.
[0021]
FIG. 4C shows a bonding material 2 ′ of a different reference form. This joining material 2 'is formed by bending a long and rectangular aluminum alloy plate material into a U-shaped section 6 at the center along its longitudinal direction, and bending both left and right ends 90 degrees opposite to each other. A horizontal piece 4 is formed. In this case, since the thickness of the horizontal piece 4 is about half that of the vertical piece 6, it is necessary to consider the conditions of the plate members 1a and 1b and the respective parts of the tool 10 with this in mind. It should be noted that even if some gaps remain in the vertical piece 6 having a U-shaped cross section, it can be eliminated by pressing strongly when sandwiched between the end faces of the plate members 1a and 1b, and the horizontal piece 4 is inclined slightly upward. However, it is possible to use for friction stir welding by the axial pressing force of the tool 10 by the bobbin 12.
[0022]
FIG. 5 relates to a joining method of different reference forms.
FIG. 5A shows plate members 1a and 1b having a thickness t of about 14 to 25 mm, which is thicker than that of the above embodiment, and a pair of bonding materials 2 and 2 fixed between them. As shown in FIG. 5 (A), each joining member 2 is sandwiched and fixed by inserting the vertical pieces 6 so as to approach each other from both sides of the end faces of the plate members 1a and 1b. In this case, the total height f of the two vertical pieces 6 is substantially the same as or slightly longer than the plate thicknesses t of the plate members 1a and 1b.
Next, by using the tool 10, friction stir welding is performed together with the bonding material 2 located on one surface of the plate materials 1a and 1b to form the same joining line W as described above. Furthermore, the friction stir welding is performed together with the bonding material 2 located on the back surface from the other front (back) surface of the plate materials 1a and 1b to form a similar bonding line W.
[0023]
As a result, as shown in FIG. 5B, the pair of joining lines W are positioned symmetrically, and the bottom portions Wc overlap each other. In addition, the shallow concave grooves Wa and the convex portions Wb on the surface of each joint line W are both located outward from the front and back surfaces of the plate materials 1a and 1b, and a bond with high strength can be obtained.
[0024]
In the state shown in FIG. 5A, the pair of joining materials 2 and 2 are not used, and as shown in FIG. It is also possible to use an extruded shape 2 ″ having a letter shape. The height f of the vertical piece 6 of the extruded shape 2 ″ having a substantially E-shaped cross section is slightly larger than the thickness of the plates 1a and 1b to be joined. Just keep it. This extruded section 2 ″ having a substantially E-shaped cross section is inserted along the longitudinal direction between the end faces of the adjacent plates 1a and 1b. This reduces the thickness of about 20 mm thick aluminum alloy plates. With the bonding material, the friction stir welding can be surely performed while facilitating positioning.
FIG. 6B relates to a bonding material of a different reference form.
As shown in FIG. 6 (B), a pair of bonding materials 2a, 2a having a cross-sectional channel shape can be sandwiched and fixed between the end faces of the pair of aluminum alloy sheets 1a, 1b. In this embodiment, the pair of bonding materials 2a and 2a becomes the bonding material of the present invention.
[0025]
FIG. 7 relates to an embodiment of the joining method of the present invention.
As shown in FIG. 7 (A), the plate thicknesses of the pair of aluminum alloy plates 1a and 1b to be joined are different. At this time, as shown in FIG. 7 (B), the vertical piece 6 of the bonding material 2b of cross section T-shaped having a water Tairahen 4b and the vertical piece 6, fixed by sandwiching between the plate members 1a, 1b. The horizontal piece 4b has an inclined upper surface 4c and uneven bottom surfaces 4d and 4e, and the bottom surfaces 4d and 4e are brought into contact with the surfaces of the plate members 1a and 1b during the fixing .
Next, the tool 10 is similarly inclined so that friction stir welding is performed so that the friction pins 16 are orthogonal to the inclined upper surface 4c of the horizontal piece 4b . At this time, the friction pin 16 is vertical piece 6 and the plate member 1a, to inter-1b, while rotating in a state of entering obliquely rear direction in FIG. 7 (B), i.e., plate 1a, in the longitudinal direction between 1b Move along .
As a result, as shown in FIG. 7 (C), a joining line W having an inclined surface including the concave groove Wa and the pair of convex portions Wb is formed between the plate members 1a and 1b following the horizontal piece 4b and the tool 10. Can be joined together.
[0026]
In addition, it is also possible to form a chamfer at the outer corner portion of the horizontal piece of the joining material having a substantially T-shaped or substantially E-shaped cross section, or to use an extruded profile having a cross-sectional shape with a curved surface that is loosely curved on the surface of the horizontal piece. Is possible.
[0027]
【The invention's effect】
According to the joining method of the present invention (Claim 1), the horizontal piece of joining material that is plasticized and fluidized together with a pair of aluminum or aluminum alloy plate materials having different plate thicknesses compensates for the reduction in plate thickness between the respective plate materials. It is possible to butt-join thin-walled plates by friction stir welding with a required strength. In addition, the bonding material can be fixed simply by sandwiching the vertical piece between the pair of plate members, and can be easily performed by a normal plate member restraining method.
Moreover, according to the joining method of Claim 2, it becomes possible to more reliably perform the butt | joint joining by the friction stir welding of board | plate materials from which board thickness differs and thin.
[Brief description of the drawings]
FIGS. 1A to 1C are partial schematic views showing steps of a joining method according to a reference embodiment.
FIG. 2A is a schematic diagram for explaining the relationship between a plate material and a bonding material in a reference embodiment, and FIG. 2B is a schematic diagram for explaining the relationship between the bonding material and a tool in such a configuration.
FIGS. 3A to 3D are partial schematic views showing respective steps of a joining method according to a reference embodiment. FIGS.
FIGS. 4A and 4B are partial schematic views showing each joint obtained by the joining method of the reference form, and FIG. 4C is a partial schematic view of a process using a joining material of a different reference form.
FIGS. 5A and 5B are partial schematic views showing respective steps of a joining method of different reference forms. FIGS.
FIGS. 6A and 6B are partial schematic views showing a joining method of still another reference embodiment.
FIGS. 7A to 7C are partial schematic views showing each step of a bonding method according to an embodiment of the present invention.
FIGS. 8A to 8C are schematic views showing steps of conventional friction stir welding, and FIGS. 8D and 9E are partial schematic views showing steps of friction stir welding between extruded shapes.
[Explanation of symbols]
1a, 1b ... Aluminum alloy plate 2b ………… Joint 4b ………… Horizontal piece
4c ………… Top surface
4d, 4e ... bottom surface 6 ......... vertical piece 12 ......... bobbin 14 ......... surface restraint 16 ......... friction pin W ............... joining line

Claims (3)

Between the end surfaces of the pair of aluminum or aluminum alloy sheet thickness are different, clamp the vertical piece of the bonding material of a substantially T-shaped, and contact the bottom surface of the stepped in the horizontal plate of the bonding material on the front surface of the plate member A process of
From the surface side of the pair of aluminum or aluminum alloy plate members, press the inclined upper surface of the horizontal piece of the bonding material with the surface restraining portion on the bottom surface of the rotating bobbin, and hang down from the center of the surface restraining portion and the surface restraining portion. The friction pins that rotate simultaneously penetrate through the horizontal piece of the joining material, and enter the slant and a predetermined depth between the vertical piece and the end faces of the plate materials , and the plate material while rotating the bobbin and the friction pins. And a step of performing friction stir welding by moving along the longitudinal direction between the end faces of each other,
Forming a joining line whose surface is inclined along the longitudinal direction between the pair of plate members;
A method for joining aluminum or aluminum alloy sheets. The bobbin and the friction pin are used while being inclined so as to be orthogonal to the inclined upper surface of the horizontal piece of the bonding material ,
The method for joining aluminum or aluminum alloy sheets according to claim 1. The bonding material is an extruded shape made of aluminum or aluminum alloy having the same composition as or different from the aluminum or aluminum alloy plate .
The method for joining aluminum or aluminum alloy sheets according to claim 1 or 2.

Images