JP2023139940A - Method of joining dissimilar metals - Google Patents

Abstract

To join metals with sufficient strength.SOLUTION: A method of joining dissimilar metals is provided in which lower metal material 11 and upper metal material 12 formed with a vertically-penetrating hole 12c and having a melting point higher than that of the lower metal material 11 are joined in such a manner that the lower metal material 11 and the upper metal material 12 overlap each other. The joining method includes the steps of: vertically overlapping the lower metal material 11 and the upper metal material 12; melting an alloy member 13 including the same metal as the lower metal material 11 and filling the melted members in the hole portion 12c; and curing the alloy member 13 filled in the hole portion 12c thereby joining the lower metal material 11 and the upper metal material 12.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a method for joining dissimilar metals.

In recent years, methods of welding dissimilar metals have become known. For example, copper is used in stators and the like used in vehicles, but due to concerns about the rising price of copper, it is conceivable to replace it with alternatives such as aluminum.

Since aluminum has a higher electrical resistance than copper, it is important to select the most suitable material, such as forming high current and voltage parts such as power lines with pure copper, and forming low current parts such as bus bars with aluminum. Should.

Patent Document 1 discloses a dissimilar electric member such as a bus bar in which copper and aluminum are butted together and laser welded.

JP2017-123318A

In the generation of dissimilar electrically powered members by laser welding disclosed in Patent Document 1, when copper and aluminum are simultaneously welded, an alloy of copper and aluminum is generated. This alloy is ideal in terms of strength if it is made of the same volume of copper and aluminum, but it is brittle whether it is an alloy that contains a large amount of aluminum or an alloy that contains a large amount of copper. In particular, copper and aluminum have different melting points, so if you try to weld them at the same time, the aluminum will melt first, and if you weld them as is, you will end up with an alloy that contains a lot of aluminum, which has a low melting point. Therefore, unless the bonding conditions are set strictly, an alloy of the same volume cannot be produced, and copper and aluminum often cannot be bonded with sufficient strength.

The present disclosure has been made in view of the problems described above, and provides a method for joining dissimilar metals by joining metals with sufficient strength.

A method for joining dissimilar metals according to the present disclosure includes stacking and joining a lower metal material and an upper metal material having a vertically penetrating hole and having a higher melting point than the lower metal material. The joining method includes a step of stacking the lower metal material and the upper metal material vertically, and a step of melting an alloy member containing the same metal as the lower metal material and filling the hole. The method includes a step of hardening the alloy member filled in the hole to join the lower metal material and the upper metal material.
This allows joining without producing brittle alloys due to welding.

According to the present disclosure, it is possible to provide a method for joining dissimilar metals that joins metals with sufficient strength.

1 is a perspective view of a metal joined body according to a first embodiment; FIG. FIG. 2 is a cross-sectional view of the metal joined body according to the first embodiment. FIG. 3 is a diagram showing a flow for forming a metal bonded body according to the first embodiment. FIG. 3 is a cross-sectional view showing states of each process of forming a metal bonded body according to the first embodiment. FIG. 3 is a cross-sectional view showing an example in which the shape of the hole according to the first embodiment is changed. FIG. 3 is a cross-sectional view showing an example in which the extending direction of the hole according to the first embodiment is changed.

Embodiment 1
Hereinafter, a method for joining dissimilar metals according to the present embodiment will be described with reference to the drawings. FIG. 1 is a perspective view showing a state in which dissimilar metals to be joined are stacked one above the other.

As shown in FIG. 1, the metal joined body 1 includes a lower metal material 11 and an upper metal material 12. Here, the description will be made assuming that the lower metal material 11 is aluminum and the upper metal material 12 is copper. Here, terms such as "upper" and "lower" used in the following explanation are used for convenience of explanation, and do not limit the orientation of the metal bonded body 1.

In addition, both the lower metal material 11 and the upper metal material 12 are plate-shaped, and both have a wide upper and lower surface, and the plate surfaces are arranged parallel to the horizontal plane. shall be. Note that the upper surface and lower surface of the lower metal material 11 are referred to as an upper surface 11a and the lower surface 11b, and the upper surface and lower surface of the upper metal material 12 are referred to as an upper surface 12a and a lower surface 12b.

The upper metal material 12 is stacked vertically with the lower surface 12b of the upper metal material 12 in contact with the upper surface 11a of the lower metal material 11.

FIG. 2 is an example of a cross-sectional view of the metal bonded body 1 at the location indicated by the dashed line shown in FIG. As shown in FIG. 2, the upper metal material 12 is formed with a plurality of holes 12c penetrating from the upper surface 12a to the lower surface 12b. For example, the hole 12c is formed to have a substantially constant diameter from the upper surface 12a to the lower surface 12b. Further, inside the upper metal material 12, the direction in which the hole 12c extends is the up-down direction.

Note that the plurality of holes 12c can have a shape obtained by cutting out a columnar shape in the upper metal material 12, but the shape is not limited to this. Moreover, the lengths of the plurality of holes 12c in the radial direction may be different from each other.

Next, a flow for joining the lower metal material 11 and the upper metal material 12 will be described with reference to the flowchart shown in FIG. 3. Furthermore, FIGS. 4(a) to 4(c) are cross-sectional views showing the states of each process of forming the metal bonded body 1.

First, as a preliminary preparation, a plurality of holes 12c are provided in the upper metal material 12 (step S1).

As shown in FIG. 4(a), the upper metal material 12 is placed over the lower metal material 11 (step S2). That is, the lower surface 12b of the upper metal material 12 is mounted on the upper surface 11a of the lower metal material 11, facing the upper surface 11a.

As shown in FIG. 4(b), the hole 12c of the upper metal material 12 is melted and filled with an alloy member 13 containing the same metal as the lower metal material 11 (step S3). That is, the alloy member 13 here is an aluminum alloy containing aluminum as a main component. Specifically, laser build-up is performed in which the alloy member 13 is melted by irradiation with the laser 14 and poured into the hole 12c of the upper metal material 12.

Typically, the laser 14 heats the alloy member 13 to a temperature that melts the alloy member 13 but does not melt the upper metal material 12.

As shown in FIG. 4(c), the hole 12c of the upper metal material 12 is sufficiently filled with the melted alloy member 13, and a part of the alloy member 13 is disposed above the upper surface 12a, and a portion of the upper surface 12a is When the area is covered, filling with the alloy member 13 is finished.

Thereafter, the lower metal material 11 and the upper metal material 12 are joined by hardening the melted alloy member 13 (step S4). In other words, as shown in FIG. 4(c), the copper that is the upper metal material 12 is caulked in the vertical direction by the cooling contraction force of the aluminum alloy that is the alloy member 13.

As a result, aluminum, which is the lower metal material 11, and copper, which is the upper metal material 12, are not melted, so that they can be joined to each other without producing a brittle alloy.

Here, since the alloy member 13 and the lower metal material 11 are joined to each other by aluminum, a good joining is achieved. Furthermore, since the lower metal material 11 and the upper metal material 12 are joined using the strong alloy member 13, the lower metal material 11 and the upper metal material 12 can be joined with sufficient strength.

The metal bonded body 1 thus formed is used in a vehicle motor, etc., with the upper metal material 12 used as a low-resistance copper power line through which a relatively high current flows, and the lower metal material 11 used as a low-resistance copper power line through which a relatively low current flows. It can be used as, but not limited to, a flowing aluminum busbar. For example, the metal bonded body 1 can also be used in a battery.

Modifications of the present disclosure will be described below. For example, the shape of the hole 12c can be changed depending on, for example, the intended use of the metal bonded body 1.

FIG. 5 is a sectional view showing an example of a hole 12d in which the shape of the hole 12c is changed. As shown in FIG. 5, the shape of the hole 12d may be a wedge shape in which the upper surface 12a side is wider and the lower surface 12b side is narrower.

Furthermore, FIG. 6 is a sectional view showing an example of a hole 12e in which the extending direction of the hole 12c is changed. As shown in FIG. 6, when the metal bonded body 1 is used in an environment where force such as centrifugal force is applied, the extending direction of the hole 12e is adjusted from the top and bottom so that the bond is difficult to come out. It can be formed in an inclined state.

In this way, by making the shape of the hole formed in the upper metal material 12 into a wedge shape or by making the extending direction of the hole sloped, the alloy member 13 is formed in the upper metal material 12. Even if the upper surface 12a of the lower metal material 11 and the upper metal material 12 are not covered, the movement of the lower metal material 11 and the upper metal material 12 in the vertical direction can be restricted and the bonded state can be achieved.

Note that the amount of the alloy member 13 filled in the hole formed in the upper metal material 12 is increased so that the amount sufficiently covers the upper surface 12a of the upper metal material 12 regardless of the shape of the hole. can be filled.

Further, although the explanation has been made assuming that aluminum is used for the lower metal material 11 and copper is used for the upper metal material 12, the present invention is not limited to this, and the metals used for the lower metal material 11 and the upper metal material 12 as base materials can be changed arbitrarily.

Further, the alloy member 13 may be made of any material as long as it can be laminated on the lower metal material 11 and has a melting point lower than that of the upper metal material 12. That is, any material that can be joined by melting and solidifying the alloy member 13 and the lower metal material 11 without melting the upper metal material 12 may be used.

Further, the alloy member 13 can be supplied in the form of powder or wire and melted by the laser 14 to fill the hole 12c. That is, the method of supplying the alloy member 13 to the hole 12c of the upper metal material 12 can be changed arbitrarily.

Further, the method for melting the alloy member 13 is not limited to the laser 14, but may be heating using a burner or the like, and the heating method can be changed arbitrarily.

The plurality of holes 12c provided in the upper metal material 12 can be formed at predetermined intervals from each other. That is, the lower metal material 11 and the upper metal material 12 can be joined by spot welding.

Further, when melting the alloy member 13, the melting can be performed while monitoring the temperature. For this temperature monitoring, a radiation thermometer that measures infrared rays etc. emitted from the object can be used, but the method is not limited to this, and any temperature measurement method can be used to manage the welding conditions.

Note that the present invention is not limited to the above embodiments, and can be modified as appropriate without departing from the spirit. That is, the above description has been omitted and simplified as appropriate for clarity of explanation, and those skilled in the art can easily change, add, or convert each element of the embodiments within the scope of the present invention. Is possible.

For example, the lower metal material 11 and the upper metal material 12 include oxygen-free copper (alloy number: C1020, chemical symbol: OFCu), tough pitch copper (C1100, TCu), phosphorus deoxidized copper (C1220, DCu), brass 2 Species (C2700, Bs2), brass (C2801, Bs3), free-cutting brass (C2604, BsBM), chrome copper (C3234, CrCu), phosphor bronze (C5191, PB), aluminum bronze (C6191, ABB2), beryllium copper 25 alloy (equivalent to C1720, BeCu25), beryllium copper 50 alloy (equivalent to Z3234, BeCu50), nickel silver (C7521, NS), nickel silver for springs (C7521, NSS), free-cutting nickel silver (C7941, PbNS), gun metal (chemical symbol :BC6) can be used, but is not limited to this.

1 Metal joined body 11 Lower metal material 11a Upper surface 11b Lower surface 12 Upper metal material 12a Upper surface 12b Lower surface 12c Hole 12d Hole 12e Hole 13 Alloy member 14 Laser

Claims (1)

A method for joining dissimilar metals, in which a lower metal material and an upper metal material having a vertically penetrating hole formed therein and having a higher melting point than the lower metal material are stacked and joined together,
stacking the lower metal material and the upper metal material vertically;
melting an alloy member containing the same metal as the lower metal material and filling the hole;
a step of hardening the alloy member filled in the hole to join the lower metal material and the upper metal material;
A method for joining dissimilar metals.

Images