JP6148136B2 - Manufacturing method of dissimilar material joined body - Google Patents

Description

The present invention relates to a method of manufacturing a dissimilar materials bonded body. More specifically, the present invention relates to a technique of a dissimilar material joined body that joins a steel material and a light alloy material or the like and is used as a structure such as an automobile or a railway vehicle.

  In recent years, from the viewpoint of environment and fuel consumption, weight reduction is required for structural members of automobiles, structures for railway vehicles, ships, aircraft, building structures, etc., and aluminum materials, magnesium materials, CFRP, etc. are used. ing. On the other hand, compared to these materials, steel materials are characterized by low cost and good workability, and therefore, development of joints of dissimilar materials combining the two has been performed.

For example, when producing a dissimilar joint using an aluminum material and a steel material, Fe ₂ Al ₅ is formed as a binary intermetallic compound at the interface of the weld. In joining different kinds of metal materials, it is necessary to suppress the formation of brittle intermetallic compounds in order to obtain a structure with high joint strength. Therefore, a technique has been proposed in which the rivet shaft portion of a steel rivet is inserted through a member such as an aluminum material, the tip portion of the shaft portion is brought into contact with the steel material, and the vicinity of the contact portion between the steel materials is spot welded and joined. Yes.

  As a method of inserting the shaft portion of the rivet into the aluminum material or the like, a piercing method in which the shaft portion of the rivet is inserted by being pushed into an aluminum material or the like having no hole, or a hole is formed in advance in the aluminum material or the like. For example, a pilot hole system in which the shaft portion of the rivet is inserted into the hole can be used. For example, Patent Documents 1 and 2 disclose a technique in which a steel rivet is perforated and attached to an aluminum material, and the tip of the steel rivet is spot-welded to a mating steel material. According to this technique, since a rivet made of the same material and a steel material are joined, it is possible to prevent the formation of an intermetallic compound.

  Patent Document 3 discloses a dissimilar material joining technique in which a rivet is pressed against a material to be joined with an electrode at the time of spot welding, punched, and welded as it is. Furthermore, in Patent Document 4, a hole having a cross-sectional area larger than the axis of the rivet is formed in advance in the material to be joined, the rivet softened after spot welding is installed, the rivet is plastically deformed, and the material to be joined is formed. A dissimilar material joining technique for caulking is also disclosed.

JP 2009-285678 A JP 2010-207898 A JP-A-7-214338 Special table 2008-538232 gazette

  In the techniques described in Patent Documents 1 and 2, by making the shaft portion of the rivet widen toward the tip, the material to be joined such as an aluminum material can be plastically flowed, and the rivet is not easily detached from the aluminum material. can do. However, since it is difficult to forge a rivet having such a shape that spreads at the tip of the shaft, there is a problem in that it is necessary to make the rivet by cutting and the manufacturing cost of the rivet increases.

  Further, in the technique described in Patent Document 3, since the caulking is not performed on the materials to be joined, sufficient joining strength between different materials cannot be obtained. Furthermore, in the technique described in Patent Document 4, since the hole diameter through which the shaft portion of the rivet passes is large, it is necessary to align the shaft center of the rivet and the hole before welding. There is a problem that the caulking becomes uneven. As described above, the conventional method for manufacturing a joined body of different materials is not sufficient in terms of increasing the bonding strength.

Then, this invention sets it as the main objective to provide the manufacturing method of the dissimilar-material joined body which improved the dissimilar-material joining strength.

The present invention has been completed as a result of intensive studies by the present inventors in order to solve the above-described problems, and is composed of a shaft portion and a plate-shaped head, and has an axial cross section having a substantially T-shape. The shaft portion of the rivet is inserted into the first material to be joined from the tip side of the shaft portion of the rivet, and the head portion of the rivet is positioned on the surface of the first material to be joined. A step of exposing a front end surface of the first bonded material to a lower surface of the first bonded material, a step of plastically flowing the first bonded material toward the head portion of the rivet and caulking and fastening the rivet, and caulking the rivet. and entered into the first material to be joined, a step of the first material to be joined and grades to form a different second lap joint overlap and welded material, while pressing the head of the rivet at electrode By energizing the second material to be joined and the rivet, While welding with the tip of the Kijiku portion and the second material to be joined, a step of spreading by plastically deformed toward the outer edge direction distal region of the shaft portion from the shaft center, a method for manufacturing a dissimilar materials bonded body comprising provide.
In this method of manufacturing a joined body of different materials, after the rivet is caulked and fastened to the first material to be joined, the tip of the shaft portion of the rivet spreads from the center of the shaft toward the outer edge during welding. As the tip of the rivet spreads, the first material to be joined and the rivet tip are brought into engagement with each other, and the rivet is difficult to come off from the first material to be joined.
In this method of manufacturing the dissimilar material bonded body, the surface of the rivet that contacts the first material to be bonded may be covered with a coating film having a higher resistivity than that of the second material to be bonded.
Moreover, in this method for manufacturing the dissimilar material joined body, an annular groove may be provided around the base end region of the shaft portion on the surface in contact with the first material to be joined.
Moreover, in this manufacturing method of the dissimilar material joined body, a gap portion may be formed between the tip end portion of the shaft portion and the first material to be joined.
Further, in this method of manufacturing the dissimilar material joined body, a protrusion that extends from the center side toward the outer edge side is formed on the surface of the head of the rivet that contacts the first material to be joined. Good.
The second material to be bonded may have a melting point higher than that of the first material to be bonded.
In this method of manufacturing the dissimilar material joined body, the rivet may be inserted by drilling the shaft portion.
Further, in this method of manufacturing the dissimilar material joined body, the rivet may be inserted after a prepared hole is formed in the first material to be joined.
Moreover, in this manufacturing method of a dissimilar material assembly, the energization may be performed by setting the pressure of the electrode to 0.3 to 10 kN, the welding current to 2 to 200 kA, and the energization time to 5 to 1000 msec.

  According to the present invention, the dissimilar material bonding strength can be improved.

It is an axial sectional view of the dissimilar material joined body 100 of the embodiment of the present invention. It is a perspective view of the rivet 1 of the dissimilar-materials joined body 100 of the embodiment. It is an axial sectional view of the rivet 1 of the dissimilar material joined body 100 of the embodiment. FIG. 3 is an axial vertical sectional view of a shaft portion 2A of the rivet 1. 2 is an axial vertical sectional view of a shaft portion 2B of the rivet 1. FIG. FIG. 3 is an axial vertical sectional view of a shaft portion 2C of the rivet 1. It is an axis perpendicular sectional view of axis part 2D of rivet 1. It is an axis perpendicular sectional view of shaft part 2E of rivet 1. 2 is a plan view of the rivet 1. FIG. 2 is a plan view of the rivet 1. FIG. 2 is a plan view of the rivet 1. FIG. 2 is a plan view of the rivet 1. FIG. It is the bottom view and front view of rivet 1A used for the dissimilar-materials joined body of the modification of the embodiment. It is the bottom view and front view of rivet 1B which are used for the dissimilar material zygote of the modification of the embodiment. It is explanatory drawing which shows the manufacturing process of the dissimilar-material joined body 100 of the embodiment. It is explanatory drawing which shows the manufacturing process of the dissimilar-material joined body 100 of the embodiment. It is explanatory drawing which shows the manufacturing process of the dissimilar-material joined body 100 of the embodiment. It is explanatory drawing which shows the state which the rivet 1 deform | transforms in the manufacturing process of the dissimilar-material joined body 100 of the embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described in detail. Note that the present invention is not limited to the embodiments described below.

<Dissimilar material joined body 100>
First, the dissimilar material joined body 100 of the embodiment of the present invention will be described. FIG. 1 is a cross-sectional view in the axial direction of a dissimilar material assembly 100 of the present embodiment.

  The dissimilar material joined body 100 of this embodiment includes a rivet 1, a first material to be joined 10 in which the shaft portion 2 of the rivet 1 is inserted, and a second material to be joined 20 welded to the shaft portion 2. In the dissimilar material joined body 100 of the present embodiment, the tip end of the shaft portion 2 of the rivet 1 is plastically deformed by spot welding, and the tip of the shape gradually spreads from the shaft center toward the outer edge direction toward the second workpiece 20 side. Part 4 is formed. When the shaft portion 2 has a cylindrical shape, the distal end portion 4 has a shape that spreads in a flare from the proximal end portion 21 (see FIG. 2A) toward the distal end side. Hereinafter, the case where the shaft portion 2 has a cylindrical shape will be mainly described as an example. In FIG. 1, symbol A indicates a melted part (nugget).

  The first material to be bonded 10 is not particularly limited, but may be a light alloy material, specifically, aluminum, aluminum alloy (JIS standard 2000 series, 3000 series, 4000 series, 5000 series, 6000 series or 7000 series), magnesium, magnesium alloys and the like. Further, the first bonded material 10 may be CFRP or the like. This 1st to-be-joined material 10 can be used as a plate material, a shape material, a die-cast material, a casting material, or a press molding product of a plate material or an extruded material.

  In the dissimilar-material joined body of this embodiment, it is preferable that the clearance part 11 is formed between the 1st to-be-joined material 10 and the front-end | tip part 4 which spread in the flare shape of the axial part 2 of the rivet 1. FIG. The gap portion 11 is formed when the first material to be joined 10 is caulked and fastened to the rivet 1, and the gap portion 11 is formed so that the tip that extends from the axial center of the shaft portion 2 toward the outer edge is formed. It becomes the shape where the part 4 and the caulked part of the 1st to-be-joined material 10 meshed. This makes it difficult for the rivet 1 to come off from the first material to be joined 10. Furthermore, since the heat transfer of the melting part A of the rivet 1 is blocked by the gap part 11, softening due to heat of the first bonded material 10 is suppressed.

  Moreover, the 2nd to-be-joined material 20 is comprised with the material kind different from the 1st to-be-joined material 10, and although it does not specifically limit, For example, it can be made into steel materials, Specifically, high-tensile steel materials, zinc Examples thereof include a plated steel plate and stainless steel. The second material to be bonded 20 can be a plate material, a shape material, a casting material, a press-formed product of a plate material, a hot stamp product, or the like.

  From the viewpoint of anticorrosiveness, the first bonded material 10 is overlapped with the second bonded material 20 from the viewpoint of anticorrosive properties, or is applied with an adhesive containing a thermosetting resin, or bonded. A resin tape may be provided.

  Further, in the dissimilar material joined body 100 of this embodiment, the shaft diameter d1 of the shaft portion 2 of the rivet 1 and the hole diameter d2 through which the dissimilar material joining rivet 1 of the first material 2 is inserted are substantially the same. Is preferred. Here, the shaft diameter d1 indicates the diameter of a circle of the cylindrical shaft portion 2. The hole diameter d2 indicates the diameter of a circular hole formed in the first material to be joined 200 through which the shaft portion 2 is inserted. Since the shaft diameter of the shaft portion 2 of the different material joining rivet 1 and the hole diameter of the first material to be joined 10 are substantially the same, the positioning of the different material joining rivet 1 with respect to the second material to be joined 20 can be accurately performed. This makes it possible to aim the electrode 400 at the time of spot welding more accurately. Moreover, it can caulk uniformly when the 1st to-be-joined material 10 is caulked.

(Rivet 1)
Next, the rivet 1 constituting the dissimilar material joined body 100 of the present embodiment will be described. FIG. 2A is a perspective view of the dissimilar material joining rivet 1 of the present embodiment. FIG. 2B is an axial sectional view of the rivet 1.

  As shown in FIGS. 2A and 2B, the rivet 1 includes a cylindrical shaft portion 2 and a disk-shaped head portion 3 provided at one end of the shaft portion 2, and the head portion 3 with respect to the shaft portion 2. The cross section in the axial direction (the Z-axis direction in FIG. 2A), which is the direction in which the is provided, has a substantially T-shape. In the rivet 1, the shaft portion 2 is inserted through the first material to be joined 10, and the tip region 5 (region opposite to the side on which the head 3 is provided) located on the tip side of the shaft portion 2 is the second workpiece. Spot welding is performed on the bonding material 20. As a result, the dissimilar material joined body 100 in which the first material to be joined 10 and the second material to be joined 20 are joined is manufactured. Further, in the rivet 1 used in the dissimilar material joined body 100 of the present embodiment, the shaft portion 2 is spot welded to the second material to be joined 20, and the tip region 5 of the shaft portion 2 is softened by the heat of spot welding and applied with an electrode. Expands into a flare when pressed. Thereby, the dissimilar material bonded body 100 has a shape in which the first bonded material 10 and the tip end portion 4 (see FIG. 1) formed by the tip region 5 of the rivet 1 spreading in a flared shape are engaged with each other. It becomes difficult to remove from the first material to be joined 10.

  The material of the rivet 1 is preferably made of the same material type as the second material to be joined 20 in order to suppress the generation of brittle intermetallic compounds during spot welding and to prevent a reduction in joining strength. When the second bonded material 20 is a steel material such as SPCC, a galvanized steel plate, or a high-tensile steel plate, the rivet 1 is preferably a steel material such as mild steel or ordinary steel. Specifically, the rivet 1 is mainly composed of iron and may be appropriately added with alloy elements such as carbon, chromium, nickel, and molybdenum. The rivet 1 may be formed by cutting, but is more preferably forged from the viewpoint of productivity.

  Further, although not particularly limited, a projection that protrudes closer to the center with respect to the outer edge may be formed in the tip region 5 of the shaft portion 2. Furthermore, the corners of the head 3 of the rivet 1 may be chamfered.

  Further, as shown in FIGS. 2A and 2B, an annular groove 31 may be provided around the region of the proximal end portion 21 of the shaft portion 2 on the surface of the head portion 3 that contacts the first bonded material 10. . Since the annular groove 31 is provided in the base end portion 21 of the shaft portion 2 of the rivet 1, the first bonded material 10 can be plastically flowed in the groove portion, and the rivet 1 for different material bonding and the first bonded material can be joined. The caulking fastening force with the material 10 can be further improved.

  In the rivet 1 of the dissimilar material bonded body 100 of the present embodiment, at least a part of the surface of the head 3 that contacts the first material to be bonded 10 is covered with a film having a higher resistivity than the base material of the second material to be bonded 20. It may be broken. Specifically, the coating includes a rust preventive coating containing zinc, tin and / or aluminum, a polyester resin coating, a coating containing a silicone elastomer, an iron oxide coating (black skin), no Examples thereof include an electrolytic Ni-P plating film and other insulating films.

  Since such a coating is covered on the surface of the head 3 that is in contact with the first workpiece 10, the welding current flowing from the electrode to the second workpiece 20 via the rivet 1 is applied to the first workpiece. 10 can be prevented from being diverted. In this way, current concentrates and flows in the first material to be bonded 10, so that spot welding between the rivet 1 and the second material to be bonded 20 can be performed more efficiently. Note that the coating may be partially peeled as long as the welding current is not diverted.

  Moreover, in the rivet 1 used for the dissimilar material joined body 100 of the present embodiment, the shape of the shaft portion 2 is, for example, a substantially cylindrical shape, and the shape perpendicular to the axis is a circle. The sectional shape of the shaft is not particularly limited, but specific examples thereof will be described with reference to FIGS. 3A to 3E. 3A to 3E are examples of bottom views of the rivet 1. Here, the axis-perpendicular section refers to a section in the vertical direction in the above-described axial direction (Z-axis direction in FIG. 2).

  The axial vertical cross-sectional shape of the shaft portion 2A is, for example, a circle as shown in FIG. 3A. Moreover, the axial perpendicular cross-sectional shape of the axial part 2B is a petal shape, for example, as shown to FIG. 3B. Further, the axial vertical cross-sectional shape of the shaft portion 2C is, for example, a substantially triangular shape with three corners chamfered as shown in FIG. 3C. Further, the axial vertical cross-sectional shape of the shaft portion 2D may be a substantially square shape with four corners chamfered as shown in FIG. 3D. Further, the axial vertical cross-sectional shape of the shaft portion 2E may be elliptical as shown in FIG. 3E. For example, when the axial vertical cross-sectional shape of the shaft portion 2 is the shape shown in FIG. 3B, the rivet 1 is attached to the first bonded material 200 because a plurality of convex portions are provided on the circumference. When inserted, it is possible to prevent the rivet 1 from rotating. The same effect can be obtained even if the shaft portion 2 is provided with serrations.

  Further, in the rivet 1 of the dissimilar material joined body 100 of the present embodiment, the shape of the head 3 in plan view (the shape in plan view perpendicular to the Z-axis in FIG. 1) is not particularly limited. Description will be given with reference to FIG. 4A to 4D are examples of plan views of the rivet 1 for joining different materials.

  The planar view shape of the head 3A is, for example, a circle as shown in FIG. 4A. Moreover, the planar view shape of the head 3B is a substantially rectangular shape with four corners chamfered, for example, as shown in FIG. 4B. Moreover, the planar view shape of the head 3C may be an ellipse as shown in FIG. 4C. Furthermore, the plan view shape of the head 3D may be a petal shape as shown in FIG. 4D.

  Next, a modified example of the rivet used for the dissimilar material joined body of the modified example of the present embodiment will be described with reference to FIGS. 5A and 5B. 5A and 5B are a bottom view (see FIGS. 5A-a and 5B-a) and a front view (FIGS. 5A-b and 5B) of the rivets 1A and 1B used in the dissimilar material joined body of the modified example of the present embodiment. -B).

  As shown in FIG. 5A, a protrusion 6 extending from the center side toward the outer edge side may be formed on the surface of the head 3 of the rivet 1 </ b> A that contacts the first material to be joined. By providing the protruding portion 6, it is possible to prevent the rivet from rotating after the rivet 1 </ b> A is caulked and fixed to the first workpiece 10. Thereby, for example, it is possible to prevent loosening of the caulked and fastened parts due to vibrations or the like generated when using the dissimilar material joined body.

  5A shows an example in which four protrusions 6 are formed at equal intervals, the number and arrangement of the protrusions 6 are not particularly limited. For example, as shown in FIG. 5B, the rivet 1B may have a configuration in which four pairs of protrusions 7 arranged in parallel are formed.

<Method for producing dissimilar material assembly>
Next, the manufacturing method of the dissimilar material joined body 100 of this embodiment is demonstrated. FIG. 6 is an explanatory view showing an example (piercing method) of a manufacturing process of the dissimilar material joined body 100 of the present embodiment.

  First, as shown in FIG. 6 a, the first bonded material 10 is placed on a cylindrical counter punch 200, and the rivet 1 is held so that the rivet 1 and the counter punch 200 sandwich the first bonded material 10. Is disposed on the first workpiece 10. The dissimilar material joining rivet 1 is driven by the punch 300 toward the first material to be joined 10. The rivet for dissimilar material bonding 1 can also be disposed by, for example, a cassette type rivet supply guide (not shown) disposed before or after the pressing process or at a predetermined position of the mold during the press molding.

  Thus, by drilling the first material to be bonded 10 by the piercing method, the shaft diameter of the rivet 1 and the hole diameter of the first material to be bonded 10 can be made substantially the same. In addition, the caulking, which will be described later, can also cause the first bonded material 10 to plastically flow in the vicinity of the shaft portion 2 of the rivet 1, and the caulking strength can be improved. Furthermore, the accuracy of the position where the rivet 1 is inserted through the first material to be joined 10 can be improved.

  Next, as shown in FIG. 6 b, when the punch 300 is lowered and the rivet 1 is pushed into the first material to be bonded 10, a part of the first material to be bonded 10 is punched out by the shaft portion 2. The part 15 falls into the counter punch 200. Since the rivet 1 is pressed by the punch 300 toward the first workpiece 10, when the annular groove 31 is formed in the head 3, the head 3 of the first workpiece 10 and the counter punch 200. The portion sandwiched between and is pushed into the annular groove 31 formed around the shaft portion 2 of the head 3 by plastic flow.

  As a result, the shaft portion 2 penetrates the first material to be bonded 10, the first material to be bonded 10 is perforated, and the head portion 3 is positioned on the surface of the first material to be bonded 10. Is exposed on the lower surface of the first material to be joined 10 (see FIG. 6c). In addition, as shown in FIG. 6 c, the first workpiece 10 enters the annular groove 31, and the rivet 1 is caulked and fastened to the first workpiece 10. At this time, the first material to be joined 10 is caulked and fastened so as to flow toward the head 3 side of the rivet 1. In addition, since the caulking is performed in a state where the position of the shaft portion 2 of the rivet 1 in the hole through which the first material to be joined 10 is kept constant, variation in the caulking and fastening state in the axial circumferential direction is suppressed. .

  Further, it is preferable that a gap portion 11 is formed between the tip region 5 located on the tip side of the shaft portion 2 and the first bonded material 10. By forming the gap portion 11, the tip region 5 extends from the center of the shaft portion 2 toward the outer edge direction by spot welding, which will be described later, and the tip portion 4 is formed and caulked with the tip portion 4. A meshing state is formed with the material to be joined 10. In addition, a gap is provided between the first material to be bonded 10 and the second material to be bonded 20, and heat generated by welding the second material to be bonded 20 and the rivet 1 is generated in the first material to be bonded 10. Since it becomes difficult to transmit, the fall of the joint strength by the softening of the 1st to-be-joined material 10 can be suppressed.

  Such caulking and fastening of the rivet 1 to the first workpiece 10 can be performed by other methods. FIG. 7 is an explanatory view showing another example (preparation method) of the manufacturing process of the dissimilar material joined body 100 of the present embodiment.

  First, as shown in FIG. 7 a, the first bonded material 10 is placed on a die 302 having a cylindrical hole, and the punch 301 is placed above the hole of the die 302. This punch 301 is driven into the first workpiece 10.

  Next, as shown in FIG. 7 b, the punch 301 is lowered, a part of the first bonded material 10 is punched, and the punched part 16 falls into the die 302. Then, the rivet 1 is inserted so as to be fitted into the punched hole, and the rivet 1 is caulked and fastened to the first workpiece 10 in the same manner as described with reference to FIG.

  Thus, the rivet 1 can be easily inserted into the first material to be joined 10 by adopting a pilot hole method in which a pilot hole is opened in advance.

  FIG. 8 is an example of a manufacturing process of the dissimilar material bonded body 100 of the present embodiment, and describes a process of spot welding the rivet 1 that is caulked and fastened to the first bonded material 10 and the second bonded material 20. FIG.

  As shown in FIG. 8a, the first material to be joined 10 that has been caulked and fixed to the rivet 1 is carried into a resistance spot welding apparatus and is superimposed on the second material to be joined 20 to form a lap joint. At this time, the first bonded material 10 and the second bonded material 20 are arranged so that the rivet 1 is positioned between the spot electrodes 400 and 500.

  Next, as shown in FIG. 8b, the upper and lower electrodes 400, 500 are driven to approach each other. Further, a clamping force acts between the first material to be bonded 10 and the second material to be bonded 20, and a welding current is applied between the electrodes 400 and 500, whereby the different material bonding rivet 1 and the second material are bonded. The material to be joined 20 is resistance spot welded. In this way, the dissimilar material joined body 100 is obtained. At this time, the tip region 5 is plastically flowed and spreads in a flare shape by the pressure F applied by the electrodes 400 and 500, and the tip portion 4 is formed. As a result, even if a force is applied to the rivet 1 in the direction in which the rivet 1 is pulled out from the first bonded material 10, the tip 4 is caught by the first bonded material 10, so that the rivet 1 is difficult to be pulled out from the first bonded material 10.

  In the rivet 1, it is preferable that at least a part of the surface of the head 3 that contacts the first material to be bonded 10 is covered with a coating having a higher resistivity than the base material of the second material to be bonded 20. Thereby, it is possible to prevent the welding current flowing from the electrode through the rivet 1 to the second material to be bonded 20 from being shunted to the first material to be bonded 10, and the current flows in a concentrated manner in the first material to be bonded 10. In addition, spot welding between the rivet 1 and the second workpiece 20 can be performed more efficiently.

  As welding conditions, it is preferable that the applied pressure of the electrodes 400 and 500 is 0.3 to 10 kN and the welding current is 2 to 10 kA. The energization time is preferably 5 to 1000 msec. By performing welding in this range, the tip region 5 of the shaft portion 2 is easily spread in a flare shape.

  FIG. 9 is a diagram illustrating a process in which the rivet 1 used in the dissimilar material joined body 100 of the present embodiment is deformed by resistance spot welding. As shown in FIG. 9 a, the tip region 5 is melted and pressurized in the shaft portion 2 that was cylindrical before welding. Then, as shown in FIG. 9b, the tip region 5 plastically flows away from the shaft center (in the direction of arrow α in the figure), and the tip portion 4 having a flare-shaped cross section in the axial direction at the tip of the shaft portion 2. Is formed.

  As described above in detail, in the dissimilar material bonded body 100 of the present embodiment, after the rivet 1 is caulked and fixed to the first material to be bonded 10, the tip region 5 of the shaft portion 2 plastically flows, and the tip of the shaft portion 2. In addition, the tip portion 4 having a flare-shaped axial cross section is formed. Therefore, the rivet 1 in which the shaft portion 2 has a flare shape is not easily removed from the first material to be joined 10 while being firmly caulked and fastened, so that the joining strength can be improved.

  An aluminum alloy plate (AA6022) having a thickness of 1.2 mm was used as the first material to be joined, and a steel plate (SPCC) having a thickness of 1.0 mm was used as the second material to be joined. As the rivet, a head having a circular shape with a diameter of 10 mm, a cylindrical shape with a thickness of 1 mm, and a shaft portion with a length of 1 mm was used.

  The welding conditions were chromium copper alloy (diameter 16 mm, radius type) electrodes, a pressure of 1.96 kN, a welding current of 7 kA, and an energization time of 10 cycles. About the dissimilar material joined body manufactured in this way, the second material to be joined is removed, and a load of 100 N is applied from the shaft portion of the rivet toward the head (push out) to check whether or not the rivet has been removed. As a result of the confirmation, it was confirmed that the dissimilar material joined body produced by the method for producing a dissimilar material joined body according to the present invention did not come off and was excellent in joining strength.

DESCRIPTION OF SYMBOLS 1 Rivet for dissimilar materials 2 Shaft part 3 Head part 31 Annular groove 4 Tip part 5 Tip area (projection)
6, 7 Protrusions 10 First material to be bonded 20 Second material to be bonded 100 Dissimilar material bonded body 200 Counter punch 300, 301 Punch 302 Die 400, 500 Electrode

Claims (9)

A shaft portion and a plate-shaped head portion, and an axial section of the rivet having a substantially T-shape is inserted into the first material to be joined from the distal end side of the shaft portion, and the head portion of the rivet is Exposing a tip end surface of the shaft portion of the rivet to a lower surface of the first bonded material in a state of being located on a surface of the first bonded material ;
A step of plastically flowing the first material to be joined and caulking and fastening to the rivet;
A step of forming a lap joint by stacking the first material to be joined that has been caulked with the rivet and a second material to be joined that is different from the first material to be joined;
By energizing the second material to be joined and the rivet while pressing the head of the rivet with an electrode, the tip of the shaft and the second material to be joined are welded to each other. And a step of plastically deforming and expanding the tip region from the axial center toward the outer edge direction.   The manufacturing method of the dissimilar-materials joined body of Claim 1 with which the surface which contact | connects the said 1st to-be-joined material of the said rivet is covered with the coating film with a higher resistivity than the said 2nd to-be-joined material.   The manufacturing method of the dissimilar-materials joined body of Claim 1 or 2 in which the annular groove is provided in the circumference | surroundings of the base end part area | region of the said axial part in the surface which contact | connects the said 1st to-be-joined material of the said rivet.   The manufacturing method of the dissimilar-materials joined body of any one of Claims 1-3 in which the clearance gap part is formed between the front-end | tip part of the said axial part, and a said 1st to-be-joined material.   The manufacturing method of the dissimilar-material joined body of any one of Claims 1-4 with which the projection part is extended toward the outer edge side from the center side in the surface which contact | connects the said 1st to-be-joined material of the said head. Method.   The said 2nd to-be-joined material is a manufacturing method of the dissimilar-materials joined body of any one of Claims 1-5 whose melting | fusing point is higher than a said 1st to-be-joined material.   The dissimilar material joined body according to any one of claims 1 to 6, wherein the energization is performed with a pressing force of the electrode of 0.3 to 10 kN, a welding current of 2 to 200 kA, and an energization time of 5 to 1000 msec. Manufacturing method.   The manufacturing method of the dissimilar material joined body according to any one of claims 1 to 7, wherein the insertion of the rivet is performed by perforating the first material to be joined by the shaft portion.   The manufacturing method of the dissimilar-materials joined body of any one of Claims 1-7 which inserts the said axial part, after opening a prepared hole in the said 1st to-be-joined material.

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