WO2022113436A1

WO2022113436A1 - Bonded member and method for manufacturing same

Info

Publication number: WO2022113436A1
Application number: PCT/JP2021/029804
Authority: WO
Inventors: 将視尾尻; 諒吉田
Original assignee: 日本軽金属株式会社
Priority date: 2020-11-25
Filing date: 2021-08-13
Publication date: 2022-06-02
Also published as: JP2022083869A

Abstract

Provided are: a bonded member (10) which has superior bonding strength and excellent airtightness and watertightness; and a method for manufacturing the same. The bonded member (10) comprises: a first metal member (12) having a first primary surface and a second primary surface; and a second metal member (14) that is disposed on the second primary surface side of the first metal member (12), and that is bonded to at least part of the first metal member (12) via a laser welded section (20). The bonded member (10) is provided with a sheet-shaped brazing material (16) on the second primary surface side of the first metal member (12). The laser welded section (20) includes: a base molten portion (22) that is constituted by a molten integrated body of the first metal member (12), the second metal member (14), and the sheet-shaped brazing material (16); and a brazing material molten portion (24) constituted by a molten body of the sheet-shaped brazing material (16). The base molten portion (22) penetrates from the first primary surface to the second primary surface of the first metal member (12), and is formed continuously to at least a certain degree of the thickness of the second metal member (14). The brazing material molten portion (24) is closely adhered to the first metal member (12), the second metal member (14), and the base molten portion (22).

Description

Joining member and its manufacturing method

The present invention relates to a joining member and a method for manufacturing the same.

In various fields such as medical equipment, electronic parts, chemical plants, etc., including transportation equipment such as automobiles, railways, and aircraft, it is widely practiced to join multiple metal parts to manufacture large structural parts. Welding, pressure welding, brazing, and mechanical joining methods are known as methods for joining metal members.

Of these, brazing is a method of melting a brazing material made of an alloy having a melting point lower than that of the material to be joined (base material) and using this as an adhesive to join the member to be joined without melting it. Techniques such as in-fire brazing and torch brazing are used to melt the brazing material. Brazing in a furnace is a method of putting parts in a furnace and heating the whole to perform brazing, and torch brazing method is a method of locally heating parts using a gas torch and brazing. Is.

In recent years, in the brazing method, laser brazing that performs brazing using laser light has been proposed. In laser brazing, the joining portion of the member to be joined is irradiated with laser light and heated, whereby the brazing material is melted and the members are joined to each other. For example, Patent Document 1 describes a brazing step of brazing a plurality of metal members by laser brazing using a flux and a brazing material, and a high frequency of removing the flux remaining on the surface of the brazed portion. A method for manufacturing a metal bonding member having a laser pulse irradiation step and a chemical conversion treatment step of performing a chemical conversion treatment including a brazed portion is disclosed (claim 1 of Patent Document 1).

Further, in the welding method, laser welding using laser light is known. Laser welding is a method of irradiating a joint portion of a member to be joined with high-energy laser light to melt-join the member, and is different from brazing in that the member to be joined itself is melted. Laser welding is characterized by being capable of high-speed welding and having little thermal deformation, and is used, for example, when joining aluminum alloy members to manufacture automobile members and battery cases.

Patent Document 2 describes a method of joining an aluminum-based welded material and an iron-based welded material having a zinc-based coating layer on the surface to different materials by laser welding without using a brazing material. (Claim 1 and [0013] of Patent Document 2). Further, Patent Document 3 describes that an aluminum alloy plate for a battery case containing Fe, Mn, Ti and Zr is laser-welded by irradiating it with a pulsed laser (claim 1, [Patent Document 3]. 0009] and [0040]).

Japanese Unexamined Patent Publication No. 2013-176785 Japanese Unexamined Patent Publication No. 2008-023562 Japanese Patent No. 5725344

In this way, although conventional methods such as brazing and laser welding have been used to join metal members, there have been problems. In the brazing method, for example, in the case of brazing in a furnace or torch brazing, when a member made of a material having high thermal conductivity such as aluminum is brazed, the member is heated to a high temperature over a wide range. Therefore, there is a problem that the joint strength is lowered and the productivity is lowered. Further, in the laser brazing method, it is necessary to accurately feed the wire-shaped brazing material to a narrow melting range, and the brazing material lowers the temperature of the molten pool, so that there is a problem that the brazing speed becomes slow. Therefore, there were many problems in terms of production technology.

Further, in the laser welding method, there is a problem that a defect occurs in the welded portion (joint portion) and the joining characteristics deteriorate. That is, in laser welding, defects such as solidification cracks and porosity may occur in the welded portion depending on the material of the member to be joined. Solidification cracks are cracks that occur along the grain boundaries, which significantly reduce the mechanical properties of the joint. In addition, since air and moisture infiltrate the inside along the cracks, the airtightness and watertightness may be significantly deteriorated.

The present inventors have conducted diligent studies in view of such conventional problems. As a result, when joining metal members, if a sheet-like brazing material is placed between the plates and then laser welding is performed so that a predetermined structure can be obtained, it has excellent joining strength, as well as airtightness and watertightness. It was found that an excellent joining member can be obtained.

The present invention has been completed based on such findings, and an object of the present invention is to provide a joining member having high joining strength and excellent airtightness and watertightness, and a method for manufacturing the same.

The present invention includes the following aspects (1) to (8). In the present specification, the expression "-" includes the numerical values at both ends thereof. That is, "X to Y" is synonymous with "X or more and Y or less".

(1) A first metal member having a first main surface and a second main surface, and at least a part of the first metal member arranged on the second main surface side of the first metal member and via a laser welded portion. A joining member comprising a second metal member joined to the
The joining member includes a sheet-shaped brazing material on the second main surface side of the first metal member.
The laser welded portion will be composed of a base metal melt portion composed of a first metal member, a second metal member, and a melt-integrated material of the sheet-shaped brazing material, and a melt of the sheet-shaped brazing material. With a material melting part,
The base metal melting portion penetrates from the first main surface to the second main surface of the first metal member and is continuously formed up to at least a part of the thickness of the second metal member.
A joining member in which the brazing filler metal melted portion is in close contact with the first metal member, the second metal member, and the base metal melted portion.

(2) The joining member according to (1) above, wherein the first metal member and the second metal member are joined by forming a lap joint.

(3) The joining member according to (1) above, wherein the first metal member and the second metal member are joined by forming a T joint.

(4) The joining member according to any one of (1) to (3) above, wherein the first metal member and the second metal member are made of the same material.

(5) The joining member according to any one of (1) to (3) above, wherein the first metal member and the second metal member are made of different materials.

(6) The joining member according to any one of (1) to (5) above, wherein one or both of the first metal member and the second metal member are made of an aluminum-based metal.

(7) The method for manufacturing a joining member according to any one of (1) to (6) above, wherein the following steps;
A step of preparing a first metal member having a first main surface and a second main surface, a second metal member, and a sheet-shaped brazing material.
A step of producing a laminated body in which the sheet-shaped brazing material and the second metal member are arranged in this order on the second main surface side of the prepared first metal member, and a first metal member constituting the laminated body. The first main surface thereof is irradiated with a laser beam, and the second metal member is laser-welded to at least a part of the first metal member through the bonding interface.
In the laser welding step, the first metal member, the second metal member, and a part of the sheet-shaped brazing material are melt-integrated to form a base metal melting portion penetrating the joining interface of the laser welding portion. At the same time, a method of melting a sheet-shaped brazing material around the bonding interface to form a brazing material melting portion.

(8) The method according to (7) above, wherein as the first metal member and the sheet-shaped brazing material, a clad material obtained by rolling and joining the first metal member and the sheet-shaped brazing material is prepared.

According to the present invention, there is provided a joining member having excellent joining strength and excellent airtightness and watertightness, and a method for manufacturing the same.

It is a cross-sectional schematic diagram of a joining member. It is sectional drawing which shows an example of the joining member which forms a lap joint. It is sectional drawing which shows an example of the joining member which forms a T-shaped joint. It is a drawing which provides the explanation of the laser welding process. It is sectional drawing which shows an example of the joining member which forms a cross joint. It is sectional drawing which shows another example of the joining member which forms a cross joint. It is sectional drawing which shows another example of the joining member which forms a cross joint. It is sectional drawing which shows an example of the joining member which forms a square joint. It is sectional drawing which shows an example of the joining member which forms the scarf joint. It is sectional drawing which shows an example of the joining member which forms the edge joint. It is sectional drawing which shows an example of the joining member which forms the sewage joint. It is sectional drawing which shows another example of the joining member which forms the sewage joint. It is sectional drawing which shows the other example of the joining member which forms the sewage joint. It is sectional drawing which shows the other example of the joining member which forms the sewage joint. It is sectional drawing which shows an example of the joining member which forms the flare joint. It is sectional drawing which shows another example of the joining member which forms the flare joint. It is sectional drawing which shows an example of the joining member which forms a backing plate joint. It is sectional drawing which shows another example of the joining member which forms a backing plate joint. It is sectional drawing which shows an example of the joining member which forms the lap fillet joint. It is a figure which shows the layer structure of the laminated body in Example 1. FIG. It is a drawing which shows the mode of laser welding in Example 1. FIG. It is a figure which shows the layer structure of the laminated body in Example 2. It is a drawing which shows the mode of laser welding in Example 2. It is a figure which shows the layer structure of the laminated body in Example 3. FIG. It is a drawing which shows the mode of laser welding in Example 3. It is a figure which shows the layer structure of the laminated body in Example 4. It is a drawing which shows the mode of laser welding in Example 4. FIG. It is an optical microscope image of the cross section of the joining member in Example 1. It is an optical microscope image of the cross section of the joining member in Example 1. It is an optical microscope image of the cross section of the joining member in Example 2. It is an optical microscope image of the cross section of the joining member in Example 2. It is an optical microscope image of the cross section of the joining member in Example 3. It is an optical microscope image of the cross section of the joining member in Example 3. It is an optical microscope image of the cross section of the joining member in Example 4. It is an optical microscope image of the cross section of the joining member in Example 4.

A specific embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described. The present invention is not limited to the following embodiments, and various modifications can be made without changing the gist of the present invention.

1. 1. Joining member The joining member of the present embodiment is arranged on the second main surface side of the first metal member having the first main surface and the second main surface, and the first metal member via the laser welded portion. A second metal member joined to at least a part of the metal member is provided. Further, the joining member includes a sheet-shaped brazing material on the second main surface side of the first metal member. The laser welded portion includes a base metal melting portion composed of a first metal member, a second metal member, and a molten material of a sheet-shaped brazing material, and a brazing material melting portion composed of a molten material of a sheet-shaped brazing material. To prepare for. The base metal melting portion penetrates from the first main surface to the second main surface of the first metal member, and is continuously formed up to at least a part of the thickness of the second metal member. The brazing filler metal melted portion is in close contact with the first metal member, the second metal member, and the base metal melted portion.

<Metal member>
The joining member of the present embodiment is arranged on the second main surface side of the first metal member having the first main surface and the second main surface, and the first metal member via the laser welded portion. A second metal member joined to at least a part of the above. That is, the first metal member and the second metal member are joined via the laser joining portion. The shapes of the first metal member and the second metal member are not limited as long as they can form a joining member. It may be a plate material, an extruded material, or a bar material, or may have another shape.

Further, the materials of the first metal member and the second metal member are not limited as long as they can be laser welded. For example, aluminum (Al), iron (Fe), copper (Cu), titanium (Ti), nickel (Ni), or alloys containing these metals are exemplified. Further, the combination of the materials of the first metal member and the second metal member is not limited. The first metal member and the second metal member may be made of the same kind of material, or may be made of different materials.

Preferably, one or both of the first metal member and the second metal member are made of an aluminum-based metal. The aluminum-based metal is pure aluminum or an aluminum alloy. Examples of pure aluminum include 1000 series. As aluminum alloys, 2000 series (Al-Cu series) alloys, 3000 series (Al-Mn series) alloys, 4000 series (Al-Si series) alloys, 5000 series (Al-Mg series) alloys, and 6000 series (Al-) series. Examples thereof include Mg—Si based alloys and 7000 based (Al—Zn—Mg based) alloys. Particularly preferably, the first metal member is made of a 1000 series or 3000 series alloy.

<Blazed material>
The joining member of the present embodiment includes a sheet-shaped brazing material on the second main surface side of the first metal member. That is, the sheet-shaped brazing material is arranged on the second main surface side of the first metal member, in the gap with the second metal member, or around the second metal member. The sheet-shaped brazing filler metal is a component that assists in joining the first metal member and the second metal member during laser welding, and its melting point is lower than the melting points of the first metal member and the second metal member. This brazing filler metal forms a base metal melting portion together with the first metal member and the second metal member, and spreads around the bonding interface to form the brazing filler metal melting portion.

The form of the brazing material is not limited as long as it is in the form of a sheet. For example, it may be a clad material joined to the second main surface of the first metal member. Further, it may be a clad material joined to the main surface of the second metal member. The clad material is a member obtained by clad rolling (crimping) a core material and a brazing material in a hot rolling process, and is also called a brazing sheet. Here, the first metal member and / or the second metal member corresponds to the core material. The clad material may be a single-sided clad having a brazing material on one side of the core material, or a double-sided clad having a brazing material on both sides. However, the brazing material is not limited to the clad material. For example, it may be a coating film formed on at least one main surface of the first metal member and / or the second metal member. The film-forming brazing material (16) may be formed by a known thick film or thin film forming method such as plating, sputtering, vapor deposition, or chemical vapor deposition. Further, the brazing material may be a self-standing sheet separate from the metal member, for example, a foil.

The thickness of the brazing material is not limited. However, if the brazing filler metal is excessively thin, the amount of brazing filler metal required for laser welding is reduced, which may lead to poor joining. The thickness of the brazing filler metal is preferably 5 μm or more.

Since the material of the brazing material depends on the material of the first metal member and the second metal member, it cannot be unconditionally determined. When at least one of the first metal member and the second metal member is made of an aluminum-based metal, 4000-based (Al—Si-based) alloys, Al—Cu—Si-based, Al—Zn-based, and the like can be mentioned. A 4000 series alloy is suitable. The 4000 series alloy has high fluidity. The highly fluid alloy spreads thinly in the gap between the first metal member and the second metal member during laser welding to form a brazing filler metal melted portion. Therefore, the effect of improving the airtightness and the watertightness is excellent, and the stress relaxation effect of the joint can be expected.

<Laser weld>
The laser welded portion corresponds to a portion where at least a part of the first metal member and at least a part of the second metal member are joined. The laser welded portion is composed of a base metal molten portion and a brazing filler metal fused portion. Here, each of the base metal melting portion and the brazing filler metal melting portion is also referred to as a weld bead and a fillet.

<Melting part of base metal>
The base metal melting portion is composed of a first metal member, a second metal member, and a molten and integrated product of a sheet-shaped brazing material. That is, during laser welding, heat is generated on the first main surface irradiated with the laser beam of the first metal member, and this heat is transferred to the brazing material and the second metal member. In the vicinity of the region irradiated with the laser beam, the first metal member, the brazing material and the second metal member reach high temperatures, and as a result, melt to form a molten metal. Inside the molten metal, the components diffuse and mix due to heat convection. As the laser beam irradiation site moves, the molten metal cools and solidifies to form a base metal melting portion. Therefore, the base metal melting portion is a solidified product containing components derived from the first metal member, the second metal member, and the brazing material. Each component in the base metal melted portion may be uniformly distributed or may be unevenly distributed. For example, the base metal melting portion may contain a large amount of a component derived from the first metal member or may contain a large amount of a component derived from the second metal member depending on the location. Further, the joint portion may contain a large amount of components derived from the brazing material.

The base metal melting portion penetrates from the first main surface to the second main surface of the first metal member, and is continuously formed up to at least a part of the thickness of the second metal member. That is, the base metal melting portion exists in the region near the laser welded portion over the entire thickness direction of the first metal member, and further exists over a part or the entire thickness direction of the second metal member. It can also be said that the base metal melting portion is formed so as to straddle the first metal member and the second metal member and penetrate the interface between the two. In this way, the laser joint is composed of the base metal melt, which is a melt-integrated product, and is further formed so as to penetrate the interface between the first metal member and the second metal member, thereby increasing the strength at the joint. It will be possible to make it excellent. In this respect, it can be said that the base metal melting portion functions as the main joint portion.

The shape of the base metal melting part is not particularly limited. Typically, the cross section decreases from the upper surface (first main surface) of the first metal member toward the lower surface of the second metal member. As such a shape, a rotating body (cone) in which a triangle is rotated around the central axis, a rotating body (conical table) in which a trapezoid is rotated around the central axis, and a rotating body (parous line rotating body) in which a parabolic wire is rotated. And so on. In any case, the shape is not limited as long as it is a shape formed by laser welding.

<Blazed material melted part>
The brazing filler metal melt portion is composed of a sheet-shaped brazing filler metal melt. At the time of laser welding, the first metal member and the second metal member do not reach a high temperature enough to be melted around the molten metal which becomes the base metal melting portion. On the other hand, the brazing filler metal has a low melting point and therefore melts. The melted brazing filler metal cools and solidifies to form a brazing filler metal melted portion. Therefore, the brazing filler metal melted portion is a solidified product mainly containing components derived from the brazing filler metal. Even if a component derived from the first metal member or the second metal member is contained, the amount thereof is small. By examining the composition and structure, it is possible to discriminate the brazing filler metal melted portion from the base metal melted portion.

The brazing filler metal melted portion is in close contact with the first metal member, the second metal member, and the base metal melted portion. During laser welding, the brazing filler metal is melted by heat transfer from the first metal member, the second metal member, and the base metal melting portion, and the brazing filler metal melting portion is formed. At this time, the brazing filler metal melted portion is formed so as to be tightly bonded to the first metal member, the second metal member, and the base metal melted portion.

By providing the brazing material melting part, the joining strength of the joining member can be further improved. That is, the brazing filler metal melted portion is tightly joined to the first metal member and the second metal member around the base metal melted portion. The width of the joint is substantially widened, and the joint strength is increased. In this respect, it can be said that the brazing filler metal melted portion functions as an auxiliary joint portion.

Further, by providing the brazing material melting portion, it becomes possible to improve the airtightness and watertightness of the joint portion. This point will be described with reference to FIGS. 1 (a) and 1 (b). FIG. 1A is a cross-sectional view of a joining member having no brazing material and a brazing material melting portion, and FIG. 1B is a cross-sectional view of a joining member provided with a brazing material and a brazing material melting portion. .. When there is no brazing filler metal melted portion (FIG. 1 (a)), the first metal member (12) and the second metal member (14) are joined via only the base metal melted portion (22). In this case, air or moisture infiltrates through the gaps between the metal members (12, 14). Further, as described above, solidification cracks (26) may occur in the base metal melting portion (22) which is the laser welded portion. Solidification cracks (26) are a type of cracks. When a solidification crack (26) occurs in the base metal melting portion (22), air or moisture penetrates into the upper part of the metal member (12) through the solidification crack (26). Therefore, the airtightness and watertightness of the joint cannot be ensured. On the other hand, in the case of providing the brazing filler metal melted portion (FIG. 1 (b)), the periphery of the base metal melted portion (22) is sealed by the brazing filler metal (16) and the molten metal melted portion (24). ing. Therefore, even if solidification cracking (26) occurs, airtightness and watertightness are surely ensured.

<Solder form>
The type of joining of the first metal member and the second metal member is not limited as long as both are joined via the laser joining portion. Known types of joints include lap joints, T joints, cross joints, square joints, scarf joints, helicopter joints, shaving joints, flare joints, backing plate joints, and lap fillet joints. May be good.

A schematic cross-sectional view of a joining member provided with a lap joint is shown in FIGS. 2 (a) and 2 (b). FIG. 2A is an overall view of the joint member, and FIG. 2B is an enlarged view showing the vicinity of the joint portion. In this joining member (10), the first metal member (12) and the second metal member (14) form a lap joint. That is, a part of the second main surface of the first metal member (12) and a part of the main surface of the second metal member (14) are laser-bonded via the joint portion (20). Further, a sheet-shaped brazing material (16) is arranged on the second main surface of the first metal member (12), that is, between the first metal member (12) and the second metal member (14). .. Further, a base metal melting portion (22) and a brazing filler metal melting portion (24) existing around the base metal melting portion (22) are formed in the joint portion (20).

Schematic cross-sectional views of the joining member provided with the T-joint are shown in FIGS. 3 (a) and 3 (b). FIG. 3A is an overall view of the joint member, and FIG. 3B is an enlarged view showing the vicinity of the joint portion. In this joining member (10), the first metal member (12) and the second metal member (14) form a T joint and are joined. That is, a part of the second main surface of the first metal member (12) and the end surface of the second metal member (14) are laser-bonded via the joint portion (20). Further, a sheet-shaped brazing material (16) is arranged on the second main surface of the first metal member. Further, a base metal melting portion (22) and a brazing filler metal melting portion (24) existing around the base metal melting portion (22) are formed in the joint portion (20).

2. 2. Method of manufacturing a joining member The method of manufacturing a joining member of the present embodiment is as follows: a step of preparing a first metal member having a first main surface and a second main surface, a second metal member, and a sheet-shaped brazing material. (Preparation step), a step of producing a laminate in which a sheet-shaped brazing material and a second metal member are arranged in this order on the second main surface side of the prepared first metal member (lamination step), and a laminate. A step of irradiating a first main surface of the first metal member to be laser-welded to at least a part of the first metal member via a bonding interface (laser welding step) is provided. Further, in the process of laser welding, a part of the first metal member, the second metal member and the sheet-shaped brazing material are melted and integrated to form a base metal melting portion penetrating the joining interface of the laser welding portion, and the above-mentioned The sheet-like brazing material around the bonding interface is melted to form a brazing material melting portion. Details of each step will be described below.

<Preparation process>
In the preparatory step, a first metal member having a first main surface and a second main surface, a second metal member, and a sheet-shaped brazing material are prepared. The first metal member, the second metal member, and the sheet-shaped brazing material are as described above. For example, as the first metal member and the sheet-shaped brazing material, a clad material obtained by rolling and joining them can be used, and in that case, the first metal member and the sheet-shaped brazing material can be prepared as an integrated product. can. Further, as the second metal member and the sheet-shaped brazing material, a clad material obtained by rolling and joining them can be used. In that case, the second metal member and the sheet-shaped brazing material can be prepared as an integrated product. can. Further, a foil-shaped brazing material that is a self-supporting sheet can be used, and in that case, a first metal member, a second metal member, and a sheet-shaped brazing material may be prepared separately.

<Laminating process>
In the laminating step, a laminated body is produced in which the sheet-shaped brazing material and the second metal member are arranged in this order on the second main surface side of the prepared first metal member. At this time, preferably, a flux is arranged together with the sheet-shaped brazing material between the first metal member and the second metal member. Flux is a component that promotes bonding between a metal member and a brazing material. A natural oxide film may be formed on the surface of the metal member. Such an oxide film may hinder metal contact between the metal member and the brazing material and cause poor bonding. When a flux having a melting point lower than that of the brazing material is used, this flux wets the surface of the metal member during welding and destroys the surface oxide film. Therefore, poor joining can be suppressed.

The flux is not limited as long as it has a lower melting point than the brazing material and can destroy the surface oxide film of the metal member. Examples of such a flux include a non-corrosive fluoride-based flux and a corrosive chloride flux, and a non-corrosive flux is suitable. The non-corrosive flux does not corrode metal parts or brazing materials. In addition, it is not necessary to clean the joined member after welding to remove the flux, which leads to a reduction in manufacturing cost. Examples of the non-corrosive flux include NOCOLOK (registered trademark).

The procedure for producing the laminated body is not particularly limited. When a clad material obtained by rolling and joining a first metal member and a sheet-shaped brazing material is used, a flux may be applied to the surface of the brazing material of the clad material, and the second metal member may be placed on the flux. When a clad material obtained by rolling and joining a second metal member and a sheet-shaped brazing material is used, a flux may be applied to the surface of the brazing material of the clad material, and the first metal member may be placed on the flux. When a foil-like brazing material as a self-supporting sheet is used, the first metal member, the brazing material, and the second metal material may be placed in this order after applying flux to the surface of the brazing material. Alternatively, a flux may be applied to the main surfaces of the first metal member and the second metal material, and a foil-like brazing material may be placed between the applied fluxes. Further, a means of forming a film-like brazing material on the surface of the first metal member by using a known thin film forming method, applying a flux to the surface of the film-like brazing material, and then placing the second metal member on the surface is also conceivable. ..

<Laser welding process>
In the laser welding step, the first main surface of the first metal member constituting the laminated body is irradiated with laser light, and the second metal member is laser welded to at least a part of the first metal member via the bonding interface.
In this step, a part of the first metal member, the second metal member, and the sheet-shaped brazing material are melt-integrated to form a base metal melting portion penetrating the joining interface of the laser welded portion, and the periphery of the joining interface. The sheet-shaped brazing filler metal is melted to form a brazing filler metal melted portion.

The laser welding process will be described with reference to FIG. In this step, the first main surface (upper surface in the drawing) of the first metal member (12) constituting the laminated body is irradiated with the laser beam (28) to cover at least a part of the first metal member (12). The second metal member (14) is laser welded. The laser beam (28) moves in the direction indicated by the arrow in the figure. In this step, a part of the first metal member (12), the second metal member (14), and the sheet-shaped brazing material (16) are melt-integrated to form a base metal melting portion (22), and the surroundings thereof are formed. The sheet-shaped brazing material (16) is melted to form a brazing material melting portion (24).

When the main surface of a metal member is irradiated with laser light, a part of the laser energy is absorbed by the plate material, and the surface is rapidly heated. The generated heat is transferred to the inside of the plate by conduction. In addition, the surface of the plate material is instantly melted and vaporized to form a molten pool, and components with high vapor pressure are ejected as evaporation to form dents on the surface of the molten pool. The laser beam radiated to the depression is absorbed by the molten pool, and repeatedly melts, vaporizes, and ejects evaporation to form a deep hole (key hole) in the center of the molten pool. The keyhole moves with the movement of the laser beam. In addition, the molten pool is rapidly cooled and solidified. A molten pool that has been cooled and solidified is called a weld or a weld bead. The depth of the molten part is called the melting depth.

By adjusting the laser irradiation conditions, the penetration depth can be made larger than the thickness of the first metal member. In this case, the molten pool penetrates the first metal member and the brazing material and reaches the inside of the second metal member. That is, a part of the first metal member, the second metal member, and the brazing material can be melted, and as a result, the first metal member and the second metal member can be overlapped and welded. The molten metal in the molten pool is convected, and this convection mixes the metal members constituting the molten metal with the components of the brazing material. When the molten pool is cooled and solidified, a base metal molten portion containing each component of the metal member and the brazing filler metal is formed. Since the base metal melting portion is formed straddling the first metal member and the second metal member, a joint portion is formed at the interface between the first metal member and the second metal member. The interface on which this joint is formed is the joint interface.

During laser welding, the metal members around the molten pool are affected by heat, but do not melt. On the other hand, brazing filler metal with a low melting point melts. That is, heat is transferred to the brazing material and the flux by using the molten portion formed by laser welding as a heat bridge, and the brazing material and the flux are melted and wetted and spread to be brazed. When the lap joint is manufactured, the brazing material wets and spreads so as to fill the gap between the first metal member and the second metal member. The wet and spread brazing filler metal is cooled to form a brazing filler metal melted portion.

The regions of the base metal melting part and the brazing material melting part can be investigated by observing the structure and analyzing the composition in the cross section of the joined member. For example, the composition of the base metal melting portion is different from that of the first metal member, the second metal member, and the brazing material. Also, because it is rapidly cooled, its tissue is different from other parts. Therefore, by examining the structure and composition, the regions of the base metal melting portion and the brazing filler metal melting portion can be determined.

The conditions of laser welding are not particularly limited as long as the joining member of the present embodiment can be manufactured. As the laser source, a known laser such as a CO ₂ laser, a YAG laser, a semiconductor laser, an LD-pumped solid-state laser, or a fiber laser can be used. Further, the laser oscillation may be continuous oscillation or pulse oscillation. Further, conditions such as laser output, focal length, and welding speed are not limited as long as the joining member of the present embodiment can be obtained.

The optimum conditions for laser welding depend on the material and thickness of the metal member and brazing material, so this cannot be unequivocally determined. For example, the welding speed may be set to 0.5 to 5 m / min, but the welding speed is not limited to this.

If necessary, a cleaning step may be provided to clean the joined member that has undergone laser welding. In particular, when a corrosive flux is used, it is desirable to perform a cleaning treatment to remove the residual flux. On the other hand, when a non-corrosive flux is used, the cleaning treatment may not be performed.

In this way, the joining member of the present embodiment can be obtained. Since the joint member after production includes both a base metal melting portion and a brazing filler metal melting portion, the strength at the joining portion is excellent. In addition, airtightness and watertightness at the joint are ensured.

An example of a joint member forming a cross joint, a square joint, a scarf joint, a helicopter joint, a shaving joint, a flare joint, a backing plate joint, and a lap fillet joint, and laser irradiation when manufacturing these joint members. The direction of laser incident in the method of performing the above is shown in FIGS. 5 to 19.

The present invention will be described in more detail with reference to the following examples and comparative examples. However, the present invention is not limited to the following examples.

(1) Preparation of joining member [Example 1]
In Example 1, a clad material to which the first metal member and the brazing material were joined and a clad material to which the second metal member and the brazing material were joined were laser-welded to prepare a joined member. The joining member was manufactured by the following procedure.

<Preparation process>
As the upper material, a plate-shaped clad material in which A3003 material (Al—Mn-based alloy) and A4343 material (Al—Si-based alloy) were joined by hot rolling was prepared. The total thickness of this clad material was 1.6 mm, and the thickness of the A4343 material was about 7% of the total thickness. Also, as the lower material, the same clad material as the upper material was prepared. The upper material (clad material) A3003 material corresponds to the first metal member, and the A4343 material corresponds to the brazing material. Further, the lower material (clad material) A3003 material corresponds to the second metal member, and the A4343 material corresponds to the brazing material.

<Laminating process>
The upper material and the lower material were laminated via a flux as shown in FIG. Specifically, NOCOLOK flux was applied to the surface of the brazing material of the upper material. Next, the upper material and the lower material were laminated so that the surface of the upper material coated with the flux and the surface of the brazing material of the lower material faced each other. From the top to the bottom, the obtained laminated body has an upper material [A3003 (first metal member) / A4343 (wazing material)] / flux / lower material [A4343 (wazing material) / A3003 (second metal member)). ] Had a layered structure.

<Laser welding process>
As shown in FIG. 21, the laminated body was irradiated with a laser to join the upper material and the lower material. Specifically, the laser beam was irradiated while scanning the substantially central portion of the surface of the upper material constituting the laminated body. Irradiation was performed under the condition of a laser output of 2.0 kW. As a result, a joining member in which the upper material and the lower material were joined by the laser irradiation portion was obtained.

[Example 2]
In Example 2, the clad material to which the first metal member and the brazing material were bonded and the second metal member were laser welded to prepare a bonded member. The joining member was manufactured by the following procedure.

<Preparation process>
As the upper material, a plate-shaped clad material in which A3003 material and A4343 material were joined by hot rolling was prepared. The total thickness of this clad material was 2.0 mm, and the thickness of the A4343 material was about 7% of the total thickness. In addition, A6063 extruded material was prepared as a lower material. The upper material (clad material) A3003 material corresponds to the first metal member, and the A4343 material corresponds to the brazing material. Further, the lower material (A6063 extruded material) corresponds to the second metal member.

<Laminating process>
The upper material and the lower material were laminated via a flux as shown in FIG. Specifically, NOCOLOK flux was applied to the surface of the brazing material of the upper material. Next, the upper material and the lower material were laminated so that the surface of the upper material coated with the flux and the surface of the lower material face each other. The obtained laminate has a layer structure of upper material [A3003 (first metal member) / A4343 (wax material)] / flux / lower material [A6003 (second metal member)] from top to bottom. Was.

<Laser welding process>
The laminated body was irradiated with a laser as shown in FIG. 23 to join the upper material and the lower material. Irradiation was performed under the condition of laser output of 2.6 kW. As a result, a joining member in which the upper material and the lower material were joined by the laser irradiation portion was obtained.

[Example 3]
In Example 3, the first metal member and the second metal member were laser-welded via a foil-like brazing material. The joining member was manufactured by the following procedure.

<Preparation process>
An A3003 plate (thickness 2.0 mm) was prepared as the upper material, and an A6063 extruded material (thickness 2.0 mm) was prepared as the lower material. The A3003 plate material (upper material) corresponds to the first metal member, and the A6063 extruded material (lower material) corresponds to the second metal member. Further, an A4045 foil material (thickness 0.06 mm) was prepared as a brazing material.

<Laminating process>
As shown in FIG. 24, the upper material and the lower material were laminated via a brazing material and a flux. Specifically, NOCOLOK flux was applied to the respective surfaces of the upper material and the brazing material. The upper material and the brazing material are laminated so that the surface of the upper material coated with the flux and the surface of the brazing material not coated with the flux face each other, and further, the surface of the brazing material coated with the flux and the surface of the lower material face each other. A flux material and a lower material were laminated on the surface. From the top to the bottom, the obtained laminated body has an upper material [A3003 plate material (first metal member)] / flux / A4045 foil material (wax material) / flux / lower material [A6063 extruded material (second metal member). )] Had a layered structure.

<Laser welding process>
The laminated body was irradiated with a laser as shown in FIG. 25 to join the upper material and the lower material. Irradiation was performed under the condition of laser output of 2.4 kW. As a result, a joining member in which the upper material and the lower material were joined by the laser irradiation portion was obtained.

[Example 4 (comparison)]
In Example 4, the first metal member and the second metal member were laser welded without using any brazing material or flux. The joining member was manufactured by the following procedure.

<Preparation process>
An A3003 plate (thickness 2.0 mm) was prepared as the upper material, and an A6063 extruded material (thickness 2.0 mm) was prepared as the lower material. The A3003 plate material (upper material) corresponds to the first metal member, and the A6063 extruded material (lower material) corresponds to the second metal member.

<Laminating process>
The upper material and the lower material were laminated as shown in FIG. 26. The obtained laminate had a layer structure of an upper material [A3003 plate material (first metal member)] / lower material [A6063 extruded material (second metal member)] from top to bottom.

<Laser welding process>
The laminated body was irradiated with a laser as shown in FIG. 27 to join the upper material and the lower material. Irradiation was performed under the condition of laser output of 2.2 kW. As a result, a joining member in which the upper material and the lower material were joined by the laser irradiation portion was obtained.

For Examples 1 to 4, Tables 1 and 2 show the members used for manufacturing the joining members and the chemical components of the aluminum alloy.

(2) Evaluation of joint members The cross sections of the joints of the joint members obtained in Examples 1 to 4 were observed. First, using a wet grindstone cutting machine, the joining member was cut in a direction perpendicular to the joining surface and then polished to prepare a sample for observing the joining portion. The cut surface of this sample was observed using an optical microscope.

(3) Evaluation Results Optical microscope images of the cross section of the joining member of Example 1 are shown in FIGS. 28 and 29. FIG. 28 shows the entire joint member, and FIG. 29 shows the vicinity of the joint portion. Similarly, the optical microscope image of the cross section of the joining member of Example 2 is shown in FIGS. 30 and 31, the optical microscope image of the cross section of the joining member of Example 3 is shown in FIGS. 32 and 33, and the optics of the cross section of the joining member of Example 4 is shown. Microscopic images are shown in FIGS. 34 and 35.

As shown in FIGS. 28 and 29, in the joint member of Example 1, a base metal melted portion in which a core material (A3003 material) and a skin material (A4343 material) were melted and solidified was formed at the joint portion. This base metal melting portion was firmly joined so as to integrate the core material of the upper plate and the lower plate. Further, a brazing material melting portion in which the skin material (A4343) was melted and solidified was formed around the base metal melting portion. This brazing filler metal melted portion sealed the base metal melted portion. The same results as in Example 1 were obtained for the joining members of Examples 2 and 3, and the base metal melting portion and the brazing filler metal melting portion that seals the periphery thereof were formed in the joining portion.

On the other hand, in the joint member of Example 4 in which the brazing filler metal and the flux were not used, a structure similar to that of the base metal melted portion in which the metal member was melted and solidified was observed in the joint portion, but the brazing filler metal melted portion was observed around the joint portion. Was not seen. Therefore, the structure similar to the melted part of the base metal was not sealed and was exposed to the atmosphere.

From the above results, it is understood that according to the present embodiment, a joining member having excellent joining strength and excellent airtightness and watertightness can be obtained.

10 Joining member 12 1st metal member 14 2nd metal member 16 Sheet-shaped brazing material 18 Joining interface 20 Laser welding part 22 Base metal melting part 24 Brazing material melting part 26 Solidification crack 28 Laser light

Claims

The first metal member having the first main surface and the second main surface was arranged on the second main surface side of the first metal member and joined to at least a part of the first metal member via a laser welded portion. A joining member comprising a second metal member.
The joining member includes a sheet-shaped brazing material on the second main surface side of the first metal member.
The laser welded portion will be composed of a base metal melt portion composed of a first metal member, a second metal member, and a melt-integrated material of the sheet-shaped brazing material, and a melt of the sheet-shaped brazing material. With a material melting part,
The base metal melting portion penetrates from the first main surface to the second main surface of the first metal member and is continuously formed up to at least a part of the thickness of the second metal member.
A joining member in which the brazing filler metal melted portion is in close contact with the first metal member, the second metal member, and the base metal melted portion.
The joining member according to claim 1, wherein the first metal member and the second metal member form a lap joint and are joined.
The joining member according to claim 1, wherein the first metal member and the second metal member are joined by forming a T joint.
The joining member according to any one of claims 1 to 3, wherein the first metal member and the second metal member are made of the same material.
The joining member according to any one of claims 1 to 3, wherein the first metal member and the second metal member are made of different materials.
The joining member according to any one of claims 1 to 5, wherein one or both of the first metal member and the second metal member are made of an aluminum-based metal.
The method for manufacturing a joining member according to any one of claims 1 to 6, wherein the following steps;
A step of preparing a first metal member having a first main surface and a second main surface, a second metal member, and a sheet-shaped brazing material.
A step of producing a laminated body in which the sheet-shaped brazing material and the second metal member are arranged in this order on the second main surface side of the prepared first metal member, and a first metal member constituting the laminated body. The first main surface thereof is irradiated with a laser beam, and the second metal member is laser-welded to at least a part of the first metal member through the bonding interface.
In the laser welding step, the first metal member, the second metal member, and a part of the sheet-shaped brazing material are melt-integrated to form a base metal melting portion penetrating the joining interface of the laser welding portion. At the same time, a method of melting a sheet-shaped brazing material around the bonding interface to form a brazing material melting portion.
The method according to claim 7, wherein as the first metal member and the sheet-shaped brazing material, a clad material obtained by rolling and joining the first metal member and the sheet-shaped brazing material is prepared.