JP2002066758A - Thin member and its joining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin member and its joining method capable of joining to the depth more than the member thickness. SOLUTION: A thin member 1 consisting of aluminum, magnesium, copper or alloy of these, is joined by a friction agitation joining method inserting a rotating tool 6 and the thin member 1 is arranged a projecting object at the joining part of the inserted side and the opposite side of the rotating tool 6. There is provided a projection 9 at the opposite side of the inserted side of the rotating tool 6, while this projection is joined by inserting the rotating tool 6 from the opposite side of the inserted part of the rotating tool 6, the inserted depth is made bigger than the flat part of the non-joining part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel thin member made of aluminum, magnesium, copper or an alloy thereof and a joining method thereof, and in particular, to an electronic device part, a precision machine part, a housing, etc. which require a thin plate structure. The present invention relates to a joining structure of thin members and a joining method thereof.

[0002]

2. Description of the Related Art Conventional friction stir welding is intended for large structures having a thickness of more than 1 mm and is disclosed in Japanese Patent Application No. 7-505.
As described in No. 090, a rotary tool made of a material substantially harder than the workpiece is inserted into the joint of the workpiece, and the rotary tool is moved while being rotated, so that the rotary tool is continuous in the joining line direction. Low strain bonding becomes possible. Furthermore, Japanese Patent Application Laid-Open No. H11-226575 describes a method of allowing a joint to be further strained by a coolant in a joint structure of the same scale. These conventional friction stir welding methods have a diameter of 10 mm.
This is carried out by using the above-mentioned rotating tool. Further, for joining thin materials other than friction stir welding, laser welding with low heat input (JP-A-11-104866), micro-arc welding (JP-A-9-192838), or a so-called soldering or brazing method is generally used. ing.

Japanese Patent Application Laid-Open No. 2000-158154 discloses a method in which aluminum alloys having a thickness of 1 to 3 mm are butt-stirred and joined by bending both ends of each other so that their projections are on the rotating tool side. It is shown.

[0004]

However, even if the friction stir welding method applied to the large-sized structure is applied to the joining of thin-walled materials, the tool pushing force is excessive at the thin plate portion of the work, and the work is difficult to be performed when the work is constructed. Deformation occurs, and the joining operation in which the volume of the friction stirrer is large and becomes a substantially minute region cannot be performed. Since laser and arc welding are performed once in a process of melting a part of the workpiece, deformation of the workpiece after welding is inevitable. The method of soldering and brazing exposes the entire workpiece to a high temperature, so that there arises a problem that the material of the workpiece changes and the joining operation is complicated.

In the conventional joining of thin plates, no consideration is given to the back surface of the joining.

An object of the present invention is to provide a thin member in which the entire thickness of the member is joined without any unjoined portions on the back side of the joint, and a joining method thereof.

[0007]

According to the present invention, a thin member made of aluminum, magnesium, copper or an alloy thereof is joined by a friction stir welding method by inserting a rotary tool, and the thin member is connected to the rotating portion of the joint. A bead of a desired width is formed on the side opposite to the insertion side of the tool; the thin-walled member is provided with a projection on the side opposite to the insertion side of the rotary tool at the joint, and The thickness of the thin member is greater than the thickness of the flat surface of the non-joined portion; the thin member has a projection formed by inserting the rotary tool on the opposite side of the joined portion to the insertion side of the rotary tool. In the member.

Further, according to the present invention, the thickness of aluminum, magnesium, copper or an alloy thereof is 0.1 to 1 m.
The thin members of m are joined by the friction stir welding method described above by inserting a rotating tool.

[0009] The present invention relates to aluminum, magnesium,
In a joining method of a thin member made of a thin member of copper or an alloy thereof and joined by a friction stir welding method by inserting a rotating tool, the thin member is installed on a surface plate, and a portion corresponding to a joint of the surface plate A groove having a width smaller than the diameter of the rotary tool is provided, and the joining is performed while filling a part of the member in the groove; Having a projection formed by inserting a rotary tool; the thin member is provided with a projection on a surface opposite to the insertion side of the rotary tool of the joining portion, and inserting the rotary tool on a surface opposite to the projection; And the insertion depth is made larger than the thickness of the flat portion at the non-joined portion.

In addition, the aforementioned aluminum, magnesium,
Copper or an alloy thereof is characterized in that thin members having a thickness of 0.1 to 1 mm are joined to each other by the above-described friction stir welding method by inserting a rotary tool.

In the friction stir welding method, it is preferable to perform the joining while forcibly cooling the inside of the coolant of any of water, oil or inert gas, or the vicinity of the joint while applying the above-mentioned coolant.

Aluminum, magnesium, copper, or alloys based on these materials are easily melted at a temperature below the melting point by frictional heat generated when a rotary tool made of a hard metal rotating at a high speed is pressed into a portion to be joined and inserted. When the temperature rises, plastic flow occurs and the metal parts on both sides are agitated and joined. Further, by moving the tool along the joining line, a joined structure can be produced. The tool has a two-step shape having a small diameter at a tip portion pushed into a material to be joined and a large diameter at a portion in contact with a joining surface. In the conventional friction stir welding method, the rotary tool shape has a large diameter portion (corresponding to the welding width on the surface of the friction stir welding portion) having a diameter of 10 mm or more,
The small diameter portion has a diameter of about 3 to 5 mm. However, it is necessary to reduce the size of the stirring tool in the conventional friction stir welding method for a thin member, and a thin plate member having a thickness of 0.1 to 1 mm can be joined under a lower pushing load. That is, in butt joining, it is possible to produce a structure in which the thickness of the butt portion is the same and plate components having a thickness of 0.1 to 1 mm are joined. When using a large-sized tool to join such thin plates, higher pressing force and moving force are applied to the workpiece, and the workpiece is deformed during the welding, and a substantially high-quality welding is performed. I can't get it. Therefore, in joining the thin plates having a thickness in the range of 0.1 to 1 mm, the size of the large-diameter portion of the tool depends on t so that the materials on both sides can be sufficiently stirred without generating defects. It is considered that a diameter within the range of 5 mm is preferable for obtaining a good joint.

In the present invention, since the thickness t of the thin plate is considered to be 1 mm or less, the insertion depth of the rotary tool cannot be practically sufficiently inserted to the joining depth. A groove smaller than the diameter of the rotating tool is provided in the groove, and the molten material is buried in the groove to form a projection; joining is performed in advance. By forming the stir welded portion deeper than the thickness of the portion, the stir welded portion becomes a minute area, and when viewed in a cross section perpendicular to the joining line, the stirrer depth can be set to t or more, and as a result, a good joined portion can be obtained. Such a low-load, small-area joining method is called a “micro friction stir welding method”.
It can be said.

Further, the projection at the joint can be removed as it is or by grinding or cutting after joining, so that a joint having the same thickness as the member can be obtained.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

Example 1 Table 1 shows the chemical composition of a sample subjected to a friction stir welding test according to the present invention.

[0016]

[Table 1] Here, the butt joining of each thin plate sample is performed. A
Injection molded Z91D 0.7mm thick, 50m long
m, a 100 mm wide sample was prepared, and the rest were all the same in length and width as the Mg-based alloy, with a plate thickness of 0.2 mm and 0.5 mm.
mm and 1 mm were prepared. In the present embodiment, one having the projection 9 and one having the projection 9 were prepared. Each of the protrusions 9 has a width of 0.4 mm and a thickness of 0.2 mm, but may be changed according to the plate thickness. At the time of extrusion, the projection 9 can be formed by plastic working at right angles from a flat plate and crushing the end face.

In this embodiment, as shown in FIG. 1, a plate material sample 1 of two workpieces is placed on an iron platen 2, and a plate material And the jig 5. A projection 9 is provided on the joint 3 between the two plate materials 1 on the side opposite to the insertion side of the rotary tool 6. The surface plate 2 is provided with a groove having a shape corresponding to the protrusion 9 formed on the workpiece or a groove having a shape corresponding to the shape of the protrusion 9 formed by inserting the rotary tool 6. Used depending on the joint. According to this embodiment, it is easy to align the workpiece along the joining line.

FIG. 2 shows an example in which projections 9 are provided at both ends of both members of the plate material sample 1 and butt-joined. Tokiwa 2
Is provided with a groove corresponding to the projection 9. Rotation tool 6
Has a diameter D of the large diameter portion of 1.5 mm, a diameter d of the small diameter portion of 0.7 mm, and the length of the small diameter portion is 5 to 10% of the plate thickness.
It is short and threaded. In this embodiment, the tool rotation speed is 18000 rpm and the welding speed is 1200 mm / mim. By moving the rotary tool 6 along the welding line, the surface trace 7 of the friction stir welding area 8 remains at a width equivalent to the tool diameter D as shown in FIG. 2, and the protrusion 9 is deeper than the plate thickness. Joining is performed, and sound joining can be performed without forming an unjoined portion on the back surface. The rotary tool 6 is
So that it does not come into contact with, and is floated according to the thickness of the joint in the range of 0.05 to 0.2 mm,
The thickness of the projection 9 is set accordingly. In the present embodiment, since the projections 9 are formed, sufficient bonding is always performed up to the back surface, so that very good bonding with no unbonded on the back side can be obtained.

This result is the same even when water cooling is performed at the time of joining, and the deformation after joining is extremely small. In the friction stir welding method, defects are likely to occur at the start and end portions of the joint. Therefore, it is desirable that the start and end portions of the joint are substantially removed from the actual joint portion 3 for joining. No defect such as non-joining is found in the cross-sectional structure of the joint.

Table 2 shows the Vickers hardness of the friction stir welding material (the base material and the center of the welding) and the tensile properties of the 0.5 mm thick plate.

[0021]

[Table 2] The tensile test was performed by cutting out a strip-shaped sample. Each of the Vickers hardnesses is low at the joint, and is higher than that of the annealing comparative material. However, the aging-conditioned comparative materials of 5083-0 and 6N01-T5 do not show a clear general tendency. The results of the tensile tests all show sufficient elongation, the proof stress is higher than that of the annealed and tempered comparative material, and the fracture occurs in the heat-affected zone. The fracture position is a portion that has been heated and softened because the base metal of the joint has been rolled. Therefore, a structure in which a thin plate is partially formed and the thin plates are joined can be provided by using a sufficient supporting method of the joining portion and the joining method.

FIG. 3 shows a cross section after the protrusion 9 has been ground after bonding in FIG. Since the rotating tool 6 is inserted deeper than the thickness of the flat surface of the non-joined portion of the plate material sample 1,
The backwash is formed in a desired width. Although a center line is shown in each of the joints in FIG. 2 and FIG. 3, it is simply shown to indicate the joint.

FIG. 4 is a sectional view of the stationary plate 2 using the above-described workpiece.
3 shows a cross section obtained by providing a groove corresponding to the projection 9 formed by insertion of the rotary tool 6 and joining. The protrusion 9 has a width and a depth sufficient for bonding the joining interface on the back surface, and has a width of 0.4 mm and a thickness of 0.2 mm, and can be formed smaller than the protrusion 9 shown in FIG. I can do it. Further, since there is no need to provide a projection on the workpiece in advance, the production is easy.

[0024]

Example 2 In this example, the friction stir welding method was used to obtain the results shown in Table 1.
The suitable joining condition range and the load applied to the joining material from the tool when two thin plates having dimensions of 0.5 × 50 × 300 mm having no protrusions were joined by using the 1085 aluminum material described in “1. The diameter D of the large diameter portion of the tool used for joining was 3.0 mm, and the diameter d of the small diameter portion was 1.5 mm. FIG. 5 shows appropriate joining speeds and tool rotation speeds. In the proper condition range 24 shown in FIG. 5, no defect is found in the joint, and the joining can be performed reliably. In addition, as shown in FIG. 6, the load became 600 N or less, and a so-called micro-FSW joining technique was developed as originally planned. In FIG. 6, the horizontal axis represents the rotation pitch obtained by dividing the welding speed (mm / min) by the tool rotation speed (rpm).

Similarly, the range of appropriate joining conditions and the load applied to the joining material from the tool when performing 7-joining were examined. The tool shape and joining conditions were all the same as in Example 6, but an auxiliary heating device 25 as shown in FIG. 9 was arranged near the tip of the tool. At this time, the tool 6 is previously heated to 300 ° C. by the auxiliary heating device 25 of the resistance heating type. FIG. 8 shows proper bonding conditions in such a case. FIG.
In the appropriate condition range 26 shown in FIG. 5, the rotational speed of the tool is shifted to a lower rotational speed side as compared with the appropriate condition range 24 shown in FIG. This is probably because the amount of heat supplied to the joint 3 by the auxiliary heating device 24 increases.

By performing the above-mentioned bonding conditions in accordance with the first embodiment, more excellent bonding can be obtained.

[0027]

According to the present invention, in joining thin members, a sufficient joining depth can be obtained with respect to the back surface, and a highly reliable joining of thin members with little distortion and little deterioration of material properties can be obtained. The structure and its friction stir welding method are obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of FIG.

FIG. 3 is a cross-sectional view of a joint showing an embodiment of the present invention.

FIG. 4 is a sectional view of a joint showing another embodiment of the present invention.

FIG. 5 is a diagram illustrating a relationship between a welding speed and a tool rotation speed.

FIG. 6 is a diagram illustrating a relationship between a vertical load and a rotation pitch.

FIG. 7 is a cross-sectional view of a joint showing an embodiment of the present invention.

FIG. 8 is a diagram illustrating a relationship between a welding speed and a tool rotation speed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Plate material sample of a workpiece, 2 ... Surface plate, 3 ... Joint part, 4 ...
Pressing plate, 5: jig, 6: rotating tool, 7: trace of stirring part surface, 8: friction stir welding area, 9: protrusion.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masayuki Doi 7-1-1, Omikacho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Hisanobu Okamura 7-chome Omikacho, Hitachi City, Ibaraki Prefecture No. 1-1 Inside Hitachi, Ltd. Hitachi Research Laboratory (72) Kinya Aota Inventor 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture F-term in Hitachi, Ltd. Hitachi Research Laboratory F-term (reference) 4E067 AA05 AA06 AA07 BG00 CA03

Claims (9)

[Claims] 1. A thin-walled member made of aluminum, magnesium, copper or an alloy thereof is joined by a friction stir welding method by inserting a rotary tool, and the thin-walled member is connected to a surface of the joint opposite to the insertion side of the rotary tool. A thin member having a bead having a desired width formed on a side thereof. 2. A thin member made of aluminum, magnesium, copper, or an alloy thereof is joined by a friction stir welding method by inserting a rotating tool, and the thin member is a surface opposite to a side of the joining portion where the rotating tool is inserted. A thin member provided with a projection on a side thereof, wherein the depth of the joined portion is larger than the thickness of the flat surface of the non-joined portion. 3. A thin-walled member made of aluminum, magnesium, copper or an alloy thereof is joined by a friction stir welding method by inserting a rotary tool, and the thin-walled member has a surface opposite to a side where the rotary tool is inserted. A thin member having a projection formed on a side thereof by inserting the rotating tool. 4. A friction stirrer according to claim 1, wherein said aluminum, magnesium, copper or an alloy thereof has a thickness of 0.1 to 1 mm between thin members by inserting said rotary tool. A thin member which is joined by a joining method. 5. A manufacturing method of a thin member made of a thin member of aluminum, magnesium, copper or an alloy thereof and joined by a friction stir welding method by inserting a rotating tool, wherein the thin member is a joint of the rotating tool. A method for joining thin members, wherein a projection is provided on a surface opposite to the insertion side, and the projection is removed after the rotary tool is inserted and joined on the surface opposite to the projection. 6. A manufacturing method of a thin member made of a thin member of aluminum, magnesium, copper or an alloy thereof and joined by a friction stir welding method by inserting a rotating tool, wherein the thin member is a joint of the rotating tool. A projection is provided on the side opposite to the insertion side, and the rotating tool is inserted on the side opposite to the projection and joined together, and the insertion depth is larger than the thickness of the flat part of the non-joined part. A method for joining thin members. 7. A method for manufacturing a thin member in which a thin member made of aluminum, magnesium, copper or an alloy thereof is joined by a friction stir welding method by inserting a rotary tool, wherein the thin member is set on a surface plate. A groove having a width smaller than the diameter of the rotating tool is provided in a portion corresponding to the joint of
A method of joining thin members, wherein the joining is performed while filling a part of the member in the groove. 8. A friction stirrer according to claim 5, wherein said aluminum, magnesium, copper or an alloy thereof is formed by inserting thin members having a thickness of 0.1 to 1 mm into each other by inserting said rotary tool. A joining method of a thin member, wherein the joining is performed by a joining method. 9. The method according to claim 5, wherein the joining by the friction stir welding method is carried out in a coolant of water, oil, or an inert gas or in the vicinity of a joint by the coolant. A method of joining thin-walled members, characterized in that they are joined while being cooled down.