JP2021035692A - Hybrid joining method for metallic member and joining structure of the member - Google Patents

Abstract

To provide a hybrid joining method for a metallic member capable of stably joining the metallic members on which a plating coat is applied, and to provide a joining structure.SOLUTION: A hybrid joining method includes: a mechanical joint process of flattening outward an end face periphery of a protrusion in a joining member by pressurizing a metallic joining member 1 and a joined member 2 in a direction compressing both members in such a state as fitting a protrusion 1c of the member 1 in a recess 2a of the member 2 to form an undercut part 1ca and to join both members integrally; and a diffusion joining process of generating a diffusion layer in the joint part of both members by charging both members joined in the mechanical joint process in a heating furnace to heat at a prescribed temperature for a prescribed time. In the mechanical joint process, diffusion joint is performed after flattening outward the end face periphery of the protrusion until the plating coat on the upper end face 10 of the protrusion in the joining member or an oxide coat breaks off.SELECTED DRAWING: Figure 1

Description

The present invention relates to a technique for joining metal members by a plurality of joining methods, and more particularly to a hybrid joining method and a joining structure of metal members in which mechanical joining and diffusion joining are combined.

Conventionally, when a composite member is manufactured by joining a joint member made of a metal material and a member to be joined, a high degree of adhesion is required at the joint portion depending on the use of the composite member. For example, in the case of a lithium battery, since a lead wire or the like is attached to the electrode terminal by welding or the like, a copper member having high conductivity and an aluminum member having high corrosion resistance are adhered to the electrode terminal so as not to increase the electrical resistance. There is a demand for a composite member that is joined by increasing the height. As a method for joining metal members in response to this kind of request, the diffusion joining method described in Japanese Patent Publication No. 59-52031 (Patent Document 1), Japanese Patent Publication No. 64-4581 (Patent Document 2) and the like is optimal. Known as the method.

Special Publication No. 59-52031 Special Publication No. 64-4581

However, in diffusion bonding, when oxide films and impurities are attached to the bonding interface, they cannot be removed, so there is a problem that diffusion bonding cannot be performed. Similarly, when one of these members is coated with a metal plating film that is difficult to diffuse-bond, the plating film remains at the joints of both members without being peeled off in the general integral joining method. There was a problem that diffusion bonding was not possible.

The present invention has been invented to solve the above problems, and an object of the present invention is to provide a hybrid joining method and a joining structure of a metal member capable of stably joining a metal member coated with a plating film. ..

The above problem is to outward the outer periphery of the end face of the convex portion of the joining member by applying pressure in the direction of compressing both members in a state where the concave portion of the metal joining member is fitted to the convex portion of the metal joining member. A mechanical joining process in which both members are integrally joined by flattening them into an undercut portion, and both members joined by the mechanical joining step are put into a heating furnace and heated at a predetermined temperature for a predetermined time. This can be solved by a hybrid joining method of metal members having a diffusion joining step of forming a diffusion layer at the joining portion of both members.

In the mechanical joining step, it is preferable to flatten the outer periphery of the end face of the convex portion outward until the plating film on the end face of the convex portion of the joining member is torn.

The diffusion bonding step is preferably a liquid phase diffusion bonding.

Further, the above-mentioned problems are a metal joining member having a convex portion, a metal joint member having a concave portion into which the convex portion of the joint member can be inserted, and a concave portion of the joint member having a convex portion of the joint member. By compressing the member to be joined in the state of being inserted into, the end face of the convex portion of the joint member is plastically processed, and the surplus wall of the member to be fastened is wrapped around to join both members in a non-detachable undercut portion. This can be solved by a hybrid joining structure of a metal member having a diffusion layer formed at the joining interface between the convex portion of the joining member and the concave portion of the member to be joined.

It is preferable that the diffusion layer is formed only on the upper surface of the undercut portion.

According to the present invention described above, even if both members are covered with an oxide film, a metal plating film that is difficult to diffuse-bond, etc., the oxide film and the plating film are formed by stretching both members by a mechanical joining process. Etc. are broken or separated, and then diffusion bonding is performed. Therefore, a sufficient diffusion layer can be generated at the bonding interface, and a solid solution-reinforced composite member with high adhesion can be provided.

It is a figure which shows the hybrid joining method of the metal member which concerns on embodiment of this invention, (a) is a mechanical joining process diagram, and (b) is a diffusion joining process diagram. The explanatory view which shows the mechanical joining process of the hybrid joining method of the metal member which concerns on embodiment of this invention in the order of steps. The vertical sectional view which shows the hybrid bonding structure of the metal member which concerns on embodiment of this invention.

Hereinafter, the hybrid joining method and the joining structure of the metal member according to the present invention will be described with reference to the drawings. The first joining method includes a mechanical joining step shown in FIGS. 1 (a) and 2 (a), (b), and (c), and a diffusion joining step shown in FIG. 1 (b).

In the mechanical joining step, a joining member 1 made of a copper material having a shaft portion 1a, a brim portion 1b, and a convex portion 1c, and a concave portion 2a that fits into the convex portion 1c while contacting the brim portion 1b are formed. It has a member 2 to be joined made of a columnar aluminum alloy material, and a receiving die 3 and a pressing die 4 in which both members can be pressurized, and the member to be joined 2 is joined by the pressurization of the pressing die 4. It is configured to be integrally joined to the member 1 to form a composite member CC.

The receiving mold 3 has an expansion hole 3a that guides a part of the member 2 to be joined and a positioning hole 3b that communicates with the opening hole 3a to position the shaft portion 1a of the joint member 1. A knockout pin 5 extending on the concentric axis thereof is arranged so as to protrude in the positioning hole 3b, and the end surface of the knockout pin 5 is configured to close the bottom of the positioning hole 3b. Further, the knockout pin 5 is configured to be positioned in the expansion hole 3a of the receiving die 3 by receiving the brim portion 1b of the joining member 1 in the positioning hole 3b and to be exposed from the receiving die 3 by the convex portion 1c of the joining member 1. Has been done. Further, when the knockout pin 5 protrudes into the positioning hole 3b after the push die 4 is retracted, the shaft portion 1a of the joining member 1 located in the positioning hole 3b is integrally joined with the joint member 2 from the receiving die 3. It is configured to be taken out.

The mechanical joining step preferably has a premolding mold 6 having premolding holes 6a as shown in FIG. 2A. The premolding die 6 is configured to premold the member 2 to be joined, which fits into the convex portion 1c of the joining member 1, into the pan head-like molding portion 2b. The premolding hole 6a of the premolding die 6 enables the surplus thickness of the member 2 to be joined to extend in a direction intersecting the pressurizing direction. Further, the premolding mold 6 is molded into a shape along the expansion hole 3a of the die 3 by receiving a part of the member 2 to be joined that fits into the convex portion 1c of the joining member 1 at the time of preforming the member 2 to be joined. At the same time, it is configured to be brought into close contact with the brim portion 1b of the joining member 1.

As shown in FIGS. 2 (b) and 2 (c), the stamp 4 plastically deforms the preformed pan head-like molded portion 2b into a flat plate-like head 2d having a predetermined thickness after the pre-molding of the member 2 to be joined. It is configured so that both members are integrally joined. Further, like the premolding die 6, the stamping die 4 increases the hardness of the bonded member 2 having a low hardness during work hardening while processing and hardening the bonded member 2, and has a high hardness through the inner wall of the recess 2a. The structure is such that the convex portion 1c of the joining member 1 is pressed.

Although the joining member 1 is made of a copper material, it may be made of a metal material having a higher hardness such as an iron material.

As shown in FIG. 1B, the heating furnace 7 in the diffusion joining step may have a structure for heating the composite member CC to be put into the furnace, and this may be eutectic of copper and aluminum in an atmospheric atmosphere. It is heated at 550 ° C., which is a point, for 2 hours or more, preferably about 4 hours. As a result, a eutectic reaction is generated at the joint portion of the composite member CC to form a diffusion layer on the new surface. Since the composite member to be charged into the heating furnace 7 can be diffusion-bonded only by being heated, a large number of composite member CCs can be charged into the heating furnace 7.

The diffusion bonding method is not limited to the liquid phase diffusion bonding described above, and may be a solid phase diffusion bonding. Further, it is preferable to heat at a eutectic point and a heating time according to the material of the joining member and the member to be joined.

As shown in FIG. 3, in the hybrid joining structure CC formed by the above hybrid joining method, in the mechanical joining step, as shown in FIG. 3, the end surface of the convex portion 1c of the joining member 1, that is, the upper end surface 10 is added. While plastically deforming so as to extend in a direction intersecting the compression direction, the outer periphery of the upper end thereof is flattened outward to form an undercut portion 1ca. Along with this, the member 2 to be joined is also plastically deformed, so that the surplus thickness wraps around the back surface 11 of the undercut portion 1ca, and the member 2 to be joined is brought into close contact with the entire surface of the undercut portion 1ca. The member 1 and the member 2 to be joined are mechanically joined to produce a composite member CC. At this time, with respect to the plating film covering the joining member 1, the plating film on the upper surface of the undercut portion 1ca is flattened outward and thus is destroyed and removed. On the other hand, on the back surface of the undercut portion 1ca, the plating film is compressed to increase the thickness.

After that, in the diffusion joining step, the composite member CC formed in the mechanical joining step is put into the heating furnace 7 in the heating step and heated at a predetermined temperature. At this time, the plating film is removed from the upper end surface 10 of the undercut portion 1ca of the joining member 1, the joining member 1 and the member to be joined 2 are in close contact with each other, and there is no air layer at the joining portion of both members. Also, the air does not sneak into the joint. Therefore, the new oxide film does not cover the new surface formed on both members constituting the joint portion, and the adhesion between the two members is very high, which is sufficient as shown on the new surface. A thick diffusion layer is created. As a result, it is possible to manufacture a composite member CC that is solid-solved and reinforced and joined at a joint portion having high adhesion.

On the other hand, the bonding interface between the joining member 1 and the member 2 to be joined becomes a barrier because the plating film is compressed and thickened in the process of the mechanical joining process except for the upper surface 10 of the undercut portion 1ca. No eutectic reaction occurs. Since the diffusion layer is inferior in durability, the fact that the diffusion layer is not formed in the portion P where the bonding interface is in contact with the external environment leads to improvement in quality.

The specific configuration of each part of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

CC ... Composite member 1 Joining member
1a Shaft
1b Brim part 1c Convex part 1ca Undercut part 2 Joined member,
2a recess 3 receiving type
4 push mold

Claims (5)

By applying pressure in the direction of compressing both members in a state where the concave portion of the metal joint member is fitted to the convex portion of the metal joint member, the outer periphery of the end face of the convex portion of the joint member is flattened outward. A mechanical joining process in which the undercut part is molded and both members are joined together.
A diffusion joining step of forming a diffusion layer at a joining portion of both members by putting both members joined by a mechanical joining step into a heating furnace and heating them at a predetermined temperature for a predetermined time.
A method for hybrid bonding of metal members, which comprises. The metal member according to claim 1, wherein in the mechanical joining step, the outer periphery of the end face of the convex portion is flattened outward until the plating film or the oxide film on the end face of the convex portion of the joining member is torn. Hybrid joining method. The hybrid bonding method for metal members according to claim 1 or 2, wherein the diffusion bonding step is a liquid phase diffusion bonding. A metal joint member with a convex part and
A metal joint member having a concave portion into which a convex portion of the joint member can be inserted,
By compressing the member to be joined with the convex portion of the joint member inserted into the concave portion of the member to be joined, the end face of the convex portion of the joint member is plastically processed and the surplus thickness of the member to be joined is wrapped around both of them. An undercut part that joins the members together so that they cannot be removed,
A diffusion layer formed at the joining interface between the convex portion of the joining member and the concave portion of the member to be joined,
A hybrid joint structure of metal members characterized by having. The hybrid bonding structure of a metal member according to claim 4, wherein the diffusion layer is formed only on the upper surface of the undercut portion.

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