JP3861719B2 - Friction stir welding method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a friction stir welding method in which a non-plastic fluid material such as a steel material is joined using a joining member made of a plastic fluid material such as metal or resin.
[0002]
[Prior art]
Generally, the friction stir welding method for joining two joining members arranged in a butted state or a superposed state is one of solid phase joining methods, and is rotated to a butted portion or a superposed portion of the joined member. A probe is inserted, while the contact portion with the probe is softened by frictional heat and stirred, the probe is cooled and solidified while being moved along the abutting portion or the overlapping portion, and both are joined. That is, as the probe moves, the softened stirring portion receives the pressure of the probe and is received by the probe passage groove, that is, plastically flows around the probe in the direction of travel, and then rapidly loses frictional heat. To cool and solidify. This phenomenon is sequentially repeated with the movement of the probe, and finally, both the joining members are joined and integrated at the butting portion or the overlapping portion.
[0003]
Since such a friction stir welding method is solid phase bonding, it is not limited by the type of material of the joining member, or due to thermal distortion at the time of joining compared to fusion welding methods such as MIG, TIG, laser welding, etc. There are advantages such as less deformation.
[0004]
As such a prior art, a friction stir welding method according to Japanese Patent No. 2794233 is known. In this method, one probe pin that rotates in the same direction is pressed against a joint portion of a joining member, and the material of the contact portion is joined by plastic flow stirring by frictional heat. This is an epoch-making joining method in which the joining member is diffusion-bonded in a solid state without melting. However, the application range of the material of the joining member is limited to a material that easily plastically flows at a low temperature, such as Al and Cu, and application to a hardly plastic fluid material such as a steel material is limited.
[0005]
[Problems to be solved by the invention]
The present invention has been made in view of the above problems, and its purpose is to enable friction stir welding in a hardly plastic fluid material such as a steel material, and a combination of materials that cannot be realized by conventional welding techniques. It is an object to provide a friction stir welding method that makes it possible to perform welding.
[0006]
[Means for Solving the Problems]
The present invention provides the friction stir welding method according to each of the claims as means for solving the above-mentioned problems.
In the friction stir welding method according to claim 1, one joining member is made of a hardly plastic flow material, and the other joining member is made of a material that is easy to plastically flow. In order to assist, the first recess is formed in a trapezoidal shape with a short side on the open side, and at a predetermined interval along the joint, and the cross-sectional shape is the thickness direction of one joining member. A second concave portion having a V-shaped cross section is formed on the other, and the probe of the tool is brought into contact with the other joining member side so as to move relatively along the joining portion. Thereby, the other joining member of the material which is easy to plastic flow plastically flows along the shape of the first and second recesses of the one joining member of the hardly plastic fluid material, and thus it is possible to realize a firm joint between them. In addition, this makes it possible to join materials that cannot be performed by the conventional technology. Further, it is possible to obtain a strong bond that does not easily break even if stress is applied in any direction in the three dimensions.
[0008]
The friction stir welding method according to claim 2 is such that the joining member of the hardly plastic material is arranged so as to sandwich the joining member of the material that easily plastically flows from both sides, and thereby, via the joining member of the material that easily plastically flows. Thus, it becomes possible to join the joining members of the hardly plastic material.
In the friction stir welding method according to claim 3 , the probe of the tool is brought into contact with both side portions of the joining member made of a material that is easy to plastically flow close to the joining portion, and is relatively moved along the joining portion. , It becomes possible to join the two with higher reliability.
[0009]
In the friction stir welding method according to claim 4 , an opening having a convex portion is formed on the inner side surface of two superposed joining members made of a hardly plastic fluid material, and a joining member made of a material that easily plastically flows is formed. Inserting into the opening and abutting and rotating the probe of the tool at one point joins two joining members, thereby enabling point joining of two joining members of hardly plastic flow material It is a thing.
The friction stir welding method according to claim 5 is a method in which the probe of the tool is not moved to a single point and is relatively moved radially around the opening, whereby the opening area of the opening has a certain size. Even if it has, the two joining members of a hardly plastic fluid material can be joined firmly.
[0010]
In the friction stir welding method according to the sixth aspect of the invention, the shape of the opening portion is a drum shape, and the shape of the joining member made of a material that easily plastically flows is specified as a cylindrical shape.
In the friction stir welding method according to claim 7 , the volume of the joining member made of a material that is easy to plastically flow is increased by a volume corresponding to a gap generated when both the joining members are set. After the members are joined, the reduction in the thickness direction of the joining member made of a material that easily plastically flows can be eliminated.
The friction stir welding method according to claim 8 is a method in which a press plate is installed beside the tool so that the softened material does not protrude from the upper surface of the joining member. The member softens and does not protrude from the upper surface of the joining member, and efficiently plastically flows into the gap between the joining members, thereby enabling reliable joining.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a friction stir welding method according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the joint shape of a joining member made of a hardly plastic flow material, and is an enlarged view for explaining the shape of a recess formed on the joining surface of the joining member of FIGS. 2, 3, and 1. FIG. 4 is a perspective view of a joining member (intermediate member) made of a material that easily plastically flows. FIG. 5 is a diagram for explaining a method of wire-joining both members by the friction stir welding method according to the first embodiment of the present invention by combining the joining members shown in FIGS. 1 and 4.
[0012]
Concave portions 12a and 12b are formed on the joining surfaces 11 of the joining members 1A and 1B made of a hardly plastic fluid material such as a steel material. FIG. 2 is an enlarged view of an embodiment of the first recess 12a. As shown in FIGS. 1 and 2, the first recess 12a is formed in a dovetail shape at a predetermined interval along the joint and in the thickness direction of the joining members 1A and 1B with the same length as the plate thickness. The cross-sectional shape thereof is a trapezoidal shape having a short side on the open side of the joint surface. As shown by an arrow E in FIG. 1, the first recess 12a is effective when the direction of the stress acts in parallel with the joint.
[0013]
FIG. 3 is an enlarged view of an embodiment of the second recess 12b formed on the joining surface 11 of the joining members 1A and 1B. The second recess 12b is formed in a V-shaped cross section in the thickness direction of the joining members 1A and 1B, and is formed on both ends of the joining surface 11 in the example shown in FIG. When the joining members 1A and 1B are joined, the second recess 12b has a shape in which the central portion in the thickness direction of the member is wide and the surface portion of the member is narrowed as shown in FIG. As indicated by F, it is effective when the direction of the stress acts in the thickness direction of the member (direction perpendicular to the joint).
In the embodiment shown in FIG. 1, the first recess 12a and the second recess 12b are formed together. However, only one recess may be used if necessary. 2 and 3 show only one example of the first and second recesses 12a and 12b, and the shape of the recess can be changed as appropriate.
[0014]
FIG. 4 shows an embodiment of a joining member (intermediate member) 2 made of a material that easily plastically flows, such as Al or Cu. In this case, the intermediate member 2 is formed in a rectangular parallelepiped.
[0015]
The friction stir welding method according to the first embodiment of the present invention is performed as shown in FIG. That is, the joining members 1A and 1B of the hardly plastic fluid material are arranged so as to sandwich the intermediate member 2 of the material that easily plastically flows so as to oppose the joining surface 11 to each other. To be clamped.
The tool 3 includes a columnar rotating body 31 and a small-diameter pin-like probe 32 protruding integrally on the end axis of the rotating body 31. The rotating body 31 and the probe 32 are integrally formed. It is designed to rotate. The rotating body 31 and the probe 32 are made of a heat-resistant material that is harder than the intermediate member 2 that is a joining member and can withstand frictional heat generated during joining.
[0016]
The probe 32 of the tool 3 configured in this way is pressed against the intermediate member 2 close to the joint, and the probe 32 is moved in the joining direction along the joint while rotating. In this case, as the movement position of the tool 3, as shown in FIG. 6, it may be moved along the center of the intermediate member 2, or it is displaced along both sides of the intermediate member 2 along the side. It may be moved. Although depending on the material of the intermediate member 2, when the width of the intermediate member 2 is relatively narrow, it is possible to join the joining members 1A and 1B only by moving the tool 3 along the center. In the case where the intermediate member 2 has a relatively large width and requires a highly reliable joint, the contact position of the probe 32 is shifted to the left and right positions of the intermediate member 2 along the side. It is preferable to move them.
[0017]
In this way, the material of the intermediate member 2 is turned into the concave portions 12a and 12b of the joining surfaces of the joining members 1A and 1B by pressing and rotating and linearly moving the material on the intermediate member 2 of the material that easily plastically flows. In this way, strong plastic bonding is possible.
In the above description, the case where the intermediate member 2 is sandwiched and joined by the joining members 1A and 1B has been described. However, the intermediate member 2 is naturally used even when the intermediate member and one joining member are brought into contact with each other and joined. It is possible.
[0018]
7-9 is a figure explaining the friction stir welding method of 2nd Embodiment of this invention. In the first embodiment, the side surfaces of the two joining members 1A and 1B are line-joined using the intermediate member 2, but in the second embodiment, the two joining members 1A and 1B are overlapped in the middle. Point joining is performed using the member 2.
As shown in FIG. 7, two joining members 1A, 1B of a hardly plastic flow material are overlapped, and an opening 13 for point joining is formed in the overlapped joining members 1A, 1B. On the inner side surface of the opening 13, a convex portion 13a is formed in an annular shape. That is, the shape of the opening 13 has a drum shape in which the opening areas on the front and back sides of the joining members 1A and 1B are large and the central part is narrowed.
[0019]
FIG. 8 shows the intermediate member 2 made of a material that easily plastically flows, and the shape of the intermediate member 2 is a cylindrical body having an outer diameter through which the narrowed portion of the opening 13 can be inserted.
[0020]
As shown in FIG. 9, in the friction stir welding method of the second embodiment, the intermediate member 2 is inserted and set in the opening 13 formed in the two overlapping joining members 1A and 1B. . As in the first embodiment, the probe 32 of the tool 3 is pressed onto the intermediate member 2, and the probe 32 is rotated to frictionally stir the intermediate material (material that easily flows plastic), thereby opening the intermediate material into the opening. By causing the plastic flow to follow the 13 drum shapes, a strong point joining state between the joining members 1A and 1B can be realized.
[0021]
In the case of this point joining, in the case where the opening area of the opening 13 is small, that is, the outer diameter of the intermediate material 2 is small, it is sufficient to contact the probe 32 at one point of the intermediate member 2 and rotate it. Although it is possible to join, if the outer diameter of the intermediate member 2 is somewhat large, or if more reliable point joining is required, the probe 32 is attached to the intermediate member 2 as shown in FIG. By moving radially toward the outer peripheral edge (periphery of the opening), a stronger and more reliable point joining is possible.
[0022]
Normally, in the friction stir welding method, there is a demerit that the dimension in the thickness direction of the intermediate member 2 is reduced by plastic flow of the intermediate material. An example of the countermeasure is shown in FIG. That is, in order to eliminate the reduction in the plate thickness direction dimension of the intermediate member 2 after joining, the volume of the intermediate member 2 is previously increased, for example, higher than the plate thickness of the joining members 1A and 1B. The volume of this increase is preferably set to a volume corresponding to a gap g generated between the members 1A and 1B and the intermediate member 2 when they are set. However, if friction stirring is performed in this state, as shown in FIG. 11, the softened intermediate material protrudes from the upper surfaces of the joining members 1A and 1B, so that proper joining cannot be performed.
[0023]
Therefore, in the friction stir welding method of this embodiment, as shown in FIGS. 12 and 13, a pressing plate 4 that presses the softened intermediate material is installed beside the tool 3, and the friction stirring is performed while pressing the pressing plate 4 from the upper surface. By doing so, the softened intermediate material does not protrude from the upper surface of the joining members 1A and 1B, and efficiently plastically flows into the gap g formed between the joining members 1A and 1B and the intermediate member 2 and is reliable. Improvements have been made to enable strong bonding.
[0024]
In the case of the point joining shown in FIG. 12, the presser plate 4 has an annular shape in which a hole 41 into which the tool 3 can be inserted is formed. In this case, the radial movement of the tool 3 is restricted.
In the case of line joining in FIG. 13, by using a horseshoe-shaped presser plate 4 opened in the traveling direction (moving direction) of the tool 3, the presser plate 4 is moved at the same moving speed as the moving speed of the tool 3. In addition, the intermediate material can be efficiently plastically flowed into the gap g, so that highly reliable joining can be performed.
In addition, in the said embodiment, although demonstrated by fixing the joining member side and moving the tool side, you may make it fix the tool side and move the joining member side. The point is that the two need only move relatively.
[0025]
As described above, the friction stir welding method of the present invention enables friction stir welding of difficult-to-plastic flow materials such as steel materials, which was impossible in the past, and further, Combination bonding is also possible.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a joint shape of a joint portion of a joining member in line joining.
FIG. 2 is an enlarged view of a first concave portion that is one embodiment formed on a joining surface of a joining member.
FIG. 3 is an enlarged view of a second concave portion that is one embodiment formed on the joining surface of the joining member, and shows an A portion of FIG. 1 in an enlarged manner.
FIG. 4 is a perspective view of an intermediate member in line joining.
FIG. 5 is a diagram illustrating a friction stir welding method according to the first embodiment of the present invention.
FIG. 6 is a diagram for explaining a movement position of a tool in line joining.
FIG. 7 is a diagram illustrating a joint shape of a joining member in point joining.
FIG. 8 is a perspective view of an intermediate member in point joining.
FIG. 9 is a diagram illustrating a friction stir welding method according to a second embodiment of the present invention.
FIG. 10 is a diagram illustrating a countermeasure against a decrease in dimension in the plate thickness direction of the intermediate member after joining.
FIG. 11 is a diagram for explaining a protrusion phenomenon of a softened intermediate material.
FIG. 12 is a view showing an example of a pressing plate in point joining.
FIG. 13 is a view showing an example of a pressing plate in line joining.
[Explanation of symbols]
1A, 1B ... Joining member (joining member of non-plastic flow material)
DESCRIPTION OF SYMBOLS 11 ... Joining surface 12a, 12b ... 1st, 2nd recessed part 13 ... Opening part 13a ... Convex part 2 ... Intermediate member (joining member of the material which is easy to carry out plastic flow)
3 ... Tool 32 ... Probe 4 ... Holding plate

Claims (8)

By contacting the probe of the rotating tool in the vicinity of the joint part of both joint members, softening the contact part with the probe with friction heat and moving the probe relatively along the joint part in a contact state while stirring, In the friction stir welding method to join the joints,
One joining member is made of a hardly plastic fluid material, and the other joining member is made of a material that easily plastically flows, and the joining surface of the one joining member is provided with a first recess so as to assist the coupling between the two. a second recess be formed,
A plurality of the first concave portions are formed at predetermined intervals along the joint portion, and the cross-sectional shape thereof is a trapezoidal shape having a short side on the open side, and
The shape of the second recess is formed in a V-shaped cross section in the thickness direction of the one joining member,
A friction stir welding method characterized in that a probe of a tool abuts against the other joining member side and moves relatively along the joining portion. FSW method as claimed in claim 1, wherein the one of the joining members, characterized in that it is arranged in a manner to sandwich the other of the joining members from both sides. 3. The friction stir welding method according to claim 2 , wherein the probe of the tool is brought into contact with both side portions of the other joining member adjacent to the joint portion and relatively moved along the joint portion. Friction stir welding method in which two joining members are spot-joined while overlapping the two joining members and abutting the probe of the rotating tool in the vicinity of the joining portion and softening and stirring the contact portion with the probe by frictional heat In
The two joining members are made of a hardly plastic flow material, and an opening having a convex portion is formed on the inner side surface of the two joining members, and a joining member made of a material that is easy to plastically flow is formed. A friction stir welding method comprising inserting the two probe members into the opening portion and causing the probe of the tool to contact and rotate at one point with the joining member that is easy to plastically flow.   The friction stir welding method according to claim 4, wherein the probe of the tool is relatively moved radially toward the periphery of the opening without being fixed at one point.   The shape of the opening portion is a drum shape in which the opening area on the front side and the back side of the two overlapping joining members is large and the middle portion is narrowed, and the shape of the joining member made of the material that is easy to plastically flow is The friction stir welding method according to claim 4 or 5, wherein the friction stir welding method has a cylindrical shape.   The volume of the joining member of the material that is easy to plastically flow is increased by the volume of the gap generated when the joining member of the hardly plastic fluidic material and the joining member of the material that easily flows plastically are set. The friction stir welding method according to any one of claims 1 to 6.   The friction stir welding method according to claim 7, wherein a press plate is installed beside the tool so that the softened material does not protrude from the upper surface of the joining member.

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