JP7114029B2 - metal joining method - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act Toyama Prefectural Industrial Technology Center Research Report No. 31 2017 Published on July 28, 2017, page 6-7

Article 30, Paragraph 2 of the Patent Act applies General Incorporated Association Welding Society National Conference Lecture Outline Vol.

The present invention relates to a metal joining method for joining different or similar metal materials in a solid state.

2. Description of the Related Art In recent years, for example, in the field of automobiles, compounding of metal components has been promoted in order to reduce vehicle weight, reduce transportation energy, and the like. In particular, various proposals have been made on the utilization of light metal materials, mainly aluminum alloys, as lightweight and high-performance materials, and on the materials and methods in which a plurality of metals are integrated using these materials.

Conventionally, as a method for joining metal materials, fusion welding is generally used to heat the material above its melting point. There is also the problem that joining itself with practical strength is difficult. For example, one of the joining methods most used in automobiles is resistance welding. This melts and welds the joining interface with Joule heat. However, this method cannot be applied to dissimilar materials due to the problem of the formation of intermetallic compounds, and even when joining similar materials, for example, aluminum, which has low electrical resistance, requires a high current. The problem is that the electrodes wear out quickly and are difficult to apply.

For this reason, as the need for dissimilar metal joining technology increases, especially in automobiles, new joining methods such as solid state joining methods to suppress the formation of intermetallic compounds are required. However, it is extremely difficult to apply the conventional solid phase bonding method to actual production. For example, in diffusion bonding, in order to remove the oxide film that greatly affects the bondability, the bonding surface must be sufficiently polished, and an atmosphere such as an inert gas is required to prevent oxidation during bonding. Long-term retention is required, and mass productivity is extremely poor. In addition, pressure welding using friction stir welding (FSW) or rolling does not only provide low strength, but also severely restricts the restraint jig and applicable shape. For example, FSW is basically limited to line or point bonding, and rolling is limited to planar bonding. With these methods, it is difficult to respond to high-cycle processing with a high degree of freedom in the applied shape and a cycle time of several seconds or less, such as point joining in space, which is performed by conventional resistance welding.

Therefore, as a solid phase bonding technique with relatively high productivity, Patent Documents 1 and 2 disclose a caulking method and materials for mechanically bonding metal materials such as aluminum. In caulking, a material is plastically deformed by a punch and a die, and members are brought into pressure contact with each other and mechanically joined by engagement of deformed portions. Further, as disclosed in Patent Document 3, there is a sheet metal joining method for joining sheet metals by pressure welding, in which a first sheet metal and a second sheet metal are superimposed and a pin is locally formed from the first sheet metal side. A sheet metal joining method has also been proposed in which the sheet metals are pressed by the expansion portion and mechanically joined by the expansion portion.

Further, as disclosed in Patent Document 4, as a material in which dissimilar metals are joined, an aluminum alloy plate material, a nickel alloy or titanium alloy plate material, and a magnesium alloy plate material are laminated, rolled and integrated. There is also a clad material formed by

In addition, as disclosed in Patent Document 5, the inventors of the present application have developed a joint member of dissimilar materials and a manufacturing method thereof using a hydraulic press device in a combination of an aluminum alloy and a magnesium alloy under static load application. developed. This connecting member uses pure titanium as the insert material, which has almost no mutual solubility with magnesium but has good reactivity with the aluminum component in the magnesium alloy, and applies high pressure to the aluminum alloy and magnesium alloy by a hydraulic system. It is a joint.

JP 2009-90354 A JP 2010-279961 A JP 2016-165760 A Japanese Unexamined Patent Application Publication No. 2015-202680 Japanese Patent No. 5830727

However, the joint structures described in Patent Documents 1, 2, and 3 are all mechanically joined, not by a metallurgical reaction, and are low in joint strength and reliability, resulting in peeling at the interface. is likely to occur. In addition, the clad material disclosed in Patent Document 4 is metallurgical bonding in a solid phase state, but due to the rolling process, the degree of freedom in the applicable shape is extremely low, and the bonding strength is low. Alternative application of conventional resistance welding used for welding is impossible. Similarly, the joining member disclosed in Patent Document 5 is also statically pressurized and joined by a hydraulic press device, and the load holding time is 20 seconds, one process is several tens of seconds or more, and the joining process It took a long time, and there was a problem in productivity when using it in the production line of automobile vehicles.

The present invention has been made in view of the above-mentioned background art, and is capable of joining metal materials in an arbitrary joining shape in a solid state at high speed and high strength, regardless of whether they are the same or different materials. An object of the present invention is to provide a metal joining method excellent in

In the present invention, a predetermined impact load is applied to a state in which the metal materials in a solid state are superimposed and mechanically pressurized to cause plastic flow at the interface where the metal materials are in contact with each other, and to increase the area of the interface. and forming a diffusion layer in which atoms of the other metal material are diffused into at least one of the metal materials at the interface to integrally bond the metal materials .

The metal material is preferably pressurized while being heated to a temperature that facilitates the plastic flow of the metal material and that does not cause a liquid phase during the pressurization. Furthermore, when the metal materials are different metals, an appropriate insert material may be interposed between the metal materials, and the pressure may be applied to join the metal materials via an intermediate layer.

The metal materials are aluminum or an aluminum alloy and magnesium or a magnesium alloy. Alternatively, the metal materials may be aluminum or aluminum alloys, or magnesium or magnesium alloys. In joining these dissimilar materials, it is preferable to interpose sheet-like or particulate titanium as an insert material. The insert material may be omitted in the joining of similar materials.

The pressing and holding time is 3 seconds or less, and it is preferable to apply an instantaneous impact load (100 mm/s or more as a speed at the time of contact with the material) when applying the load.

In addition, the present invention provides a support portion that supports the metal materials in a state where the metal materials in a solid state are superimposed on each other and allows plastic deformation of the metal materials, and the metal material held by the support portion. A diffusion layer in which atoms of at least one of the metal materials are diffused into at least one of the metal materials at the interface by applying a predetermined impact load to cause plastic flow at the interface where the metal materials are in contact with each other to increase the area of the interface. It uses a metal bonding device with a mechanical pressure device that forms a

The mechanical pressurizing device has a movable part that reciprocates and a driving part that applies force to the movable part to perform a pressurizing operation. The speed at the time of material contact is 100 mm/s or more, and the pressing operation is performed on the metal material by the support part and the movable part while sandwiching the metal material. In particular, the mechanical pressure device is a robot (robot gun) such as a C-frame having a single-axis actuator such as a hydraulic, pneumatic or electric motor capable of high-speed operation, or a mechanical press driven by a servo motor or the like. A device is preferred.

In addition, the present invention provides a support portion that supports the metal materials in a state where the metal materials in a solid state are superimposed on each other and allows plastic deformation of the metal materials, and the metal material held by the support portion. A diffusion layer in which atoms of at least one of the metal materials are diffused into at least one of the metal materials at the interface by applying a predetermined impact load to cause plastic flow at the interface where the metal materials are in contact with each other to increase the area of the interface. A metal member supply device for overlapping metal members to be joined and supplying them to the metal bonding device, and a metal joined by the mechanical pressure device It can be used in a metal member joining system provided with a metal member unloading device for unloading a member from the metal bonding device.

The metal bonding apparatus is arranged in a manufacturing line of metal products. In particular, the metal bonding apparatus is provided in a robot driven by a predetermined control device.

Further, a plurality of the metal bonding apparatuses are arranged in a metal product manufacturing line, and the metal members can be sequentially carried in and out of the plurality of metal bonding apparatuses by the metal member supply device and the metal member unloading device. It was established.

According to the metal joining method of the present invention, aluminum members, magnesium members, alloys such as iron and copper, and various other metal materials can be joined in a solid phase state efficiently and with high strength in a short time. This causes plastic flow by instantaneous impact load, removes the oxide film on the surface, forms an extremely thin diffusion layer by holding the load for an extremely short time, and generates a brittle intermetallic compound phase on the order of nanometers. by suppressing to Moreover, the shape of the metal to be joined does not matter, and the method can be applied to many metal products. Furthermore, when dissimilar metal materials are joined together, interposing an appropriate intermediate layer of an insert material enables higher strength joining.

In addition, according to the present invention, it is possible to replace conventional line equipment such as resistance welding and general-purpose press machines, and it is easy to introduce, and in particular, the resistance welding method that is most utilized in automobile vehicle production lines. As an alternative, it can be used to join aluminum alloys or combinations of dissimilar metals, which has been difficult until now, and enables high-strength joining with high productivity.

It is a schematic front view (a) before joining processing and a schematic front view (b) after joining processing showing the concept of an embodiment of the metal joining method of the present invention. 1 is a schematic perspective view of an AC servo press device, which is a metal bonding device used in one embodiment of the present invention; FIG. 1 is a schematic view of a robot gun type press device, which is a metal bonding device used in one embodiment of the present invention; FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual diagram illustrating a metal member joining system that uses a plurality of metal joining apparatuses according to an embodiment of the present invention to jointly process a plurality of joints in parallel; BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual diagram illustrating a metal member joining system that uses a plurality of metal joining apparatuses according to an embodiment of the present invention to successively process a plurality of joining points; Fig. 2 is photographs showing (a) before joining treatment and (b) after joining treatment of a magnesium alloy member and an aluminum alloy member in an example of the metal joining method of the present invention. FIG. 2 shows a transmission electron microscope bright-field image (a) of a cross-section of the joint interface between a titanium and magnesium alloy member of an example according to the metal joining method of the present invention, and its enlarged image (b). Scanning electron microscope backscattered electron image (a) of a fracture surface after a tensile test (the fracture interface is between titanium and a magnesium alloy member, and the fracture surface on the titanium side) of an example according to the metal joining method of the present invention; Furthermore, it is the enlarged image (b). 4 is a graph showing the effect of the material preheating temperature on the tensile strength in the examples according to the metal joining method of the present invention. 4 is a graph showing the effect of the thickness of the titanium insert material on the tensile strength of the example according to the metal joining method of the present invention. 4 is a graph showing the effect of load retention time (bottom dead center retention time) on tensile strength in an example according to the metal joining method of the present invention. 4 is a graph showing the effect of polishing treatment of the joint interface on the tensile strength of the examples according to the metal joining method of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail. A metal-bonded member 10 of this embodiment is formed by joining a magnesium alloy member 12 made of a magnesium alloy and an aluminum alloy member 14 made of an aluminum alloy by a manufacturing method to be described later, as in the examples shown in FIGS. It is. Between the magnesium alloy member 12 and the aluminum alloy member 14, an intermediate layer 16a of an insert member 16 made of titanium sheet material is interposed.

The magnesium alloy member 12 is an alloy containing magnesium as a main component. Magnesium alloys include aluminum, zinc, calcium, lithium, etc. as additive elements. By adjusting the composition of these additive metals, the properties of the magnesium alloy can be changed. In particular, the additive metal is preferably aluminum or zinc because of its versatility.

The aluminum alloy member 14 is an alloy containing aluminum as a main component. Additive elements for aluminum alloys include copper, manganese, silicon, magnesium, zinc, and nickel. By adjusting the composition of these additive metals, the properties of the aluminum alloy can be changed. Examples of aluminum alloys include Al--Cu alloys (duralumin), Al--Mn alloys, Al--Si alloys, Al--Mg alloys, Al--Mg--Si alloys, Al--Zn--Mg alloys, Al -Zn-Mg-Cu alloys, etc.

The insert material 16 suppresses excessive formation of a brittle intermetallic compound phase at the joint interface and increases the solid phase joint strength of the magnesium alloy member 12 and the aluminum alloy member 14. In the case of this combination of base materials, , sheet-like or particulate titanium is preferred. Nickel or copper may be used, but titanium has the highest bonding strength. In the case of a sheet, the thickness of the insert material 16 before joining treatment may be in the range of 10 μm to 3 mm. In particular, when the thickness is in the range of 0.3 mm to 1 mm, it is readily available and inexpensive, and the pressure applied to the joint surfaces is uniform, so that the insert material 16 does not break during joining. If the thickness of the insert material 16 is less than 10 μm, the insert material 16 may break when pressurized, resulting in insufficient bonding and uneven bonding strength. On the other hand, if the thickness of the insert material 16 exceeds 3 mm, there is also the drawback that the excess mass increases and the cost increases.

As shown in the transmission electron microscope bright-field images shown in FIGS. 7(a) and 7(b) of the embodiment to be described later, the metal bonding member 10 is formed at the interface between the magnesium alloy member 12 and the titanium intermediate layer 16a formed by the insert material 16. , a first diffusion layer 17 made of magnesium alloy and titanium is formed. The joint interface between the titanium and the magnesium alloy member will be the fracture interface in the tensile test of the examples described later. Similarly, a second diffusion layer (not shown) made of an aluminum alloy and titanium is formed at the interface between the aluminum alloy member 14 and the intermediate layer 16a of the insert material 16. As shown in FIG.

In the metal joint member 10, a first diffusion layer 17 is formed by plastic flow during molding at the interface between the magnesium alloy member 12 and the intermediate layer 16a of the titanium insert member 16, and metallurgical integration is achieved by bonding metal atoms together. mechanically bonded and bonded with a mechanical anchoring effect. Similarly, at the interface between the aluminum alloy member 14 and the intermediate layer 16a of the titanium insert material 16, a second diffusion layer (not shown) is formed by plastic flow during molding, and metallurgical integration is achieved by joining metal atoms together. Bonded and bonded with an anchor effect.

Next, a method for manufacturing the metal joint member 10 will be described. The metal joint member 10 is made by laminating a magnesium alloy member 12 and an aluminum alloy member 14 with a titanium insert member 16 interposed therebetween, applying a predetermined amount of heat, and applying pressure with an impact load. As a result, the magnesium alloy member 12, the intermediate layer 16a of the insert material 16, and the aluminum alloy member 14 are integrally joined.

Each condition and the like in the manufacturing method of this embodiment will be described in detail below. On the surfaces of the magnesium alloy member 12, the insert member 16 and the aluminum alloy member 14, which are in contact with each other, the oxide film or the like is broken due to the increase in the joint area due to the plastic flow, and the new surface easily and satisfactorily forms a diffusion layer. Therefore, as will be described later in the examples, even materials that have not been polished can be satisfactorily joined. The surface of each material may be ground to an average arithmetic roughness (Ra, JIS B 0601) of 0.2 μm or less. Thereby, it can be joined with a higher strength.

The preheating temperature for each material during the joining process is 250° C. to 450° C., preferably 300° C. to 400° C., when joining an aluminum alloy and a magnesium alloy using titanium as an insert material. When the preheating temperature is 250° C. or less, the plastic flow becomes smaller than when the temperature is within the above range, and as a result, the bonding may become insufficient. Further, if the preheating temperature is 450° C. or higher, heat generated during processing may cause partial liquefaction, and burrs and cracks are likely to occur, which may cause problems in terms of appearance.

The applied pressure in this case is 100 MPa to 700 MPa, preferably 200 MPa to 300 MPa, and a lower pressure may be used if the required bonding strength is obtained. When the pressure is less than 100 MPa, bonding may be insufficient compared to when the pressure is within the above range, and when the pressure exceeds 700 MPa, compared to when the pressure is within the above range. , the plastic flow becomes too large, the insert material breaks, a brittle intermetallic compound phase is generated by direct reaction between magnesium alloy and aluminum alloy, and defects such as cracks and Kirkendall voids are generated in this intermetallic compound phase. Strength may decrease.

The pressurizing method may be any pressurizing device such as a general-purpose press or a single-axis actuator capable of obtaining a desired pressure. In this embodiment, the molding time to the bottom dead center is about 0.4 seconds, and as will be described later, it is preferable that the slide speed at the time of contact of the movable portion by the press is 100 mm/s or more. In addition, the pressurization time may be extremely short as in the examples described later, the pressurization time of 5 seconds or less by a press machine or the like is sufficient, and the load holding time at the bottom dead center may be 1 second or less. It is sufficient if the necessary impact load can be applied to Further, in the case of processing with a mechanical press that cannot control pressure, the bottom dead center holding time may be set to 0 seconds by adjusting the slide so that an appropriate load is applied.

The method of heating and pressurizing is not particularly limited, for example, it may be heated in advance in an electric furnace or the like and then joined in the same manner as hot forging, or may be pressurized by laser light, flame, current, electromagnetic induction, or the like. A method of locally heating the joint to a predetermined temperature may also be used. As for the heating environment, it is preferable to perform the heating under atmospheric pressure in terms of productivity and cost, but it may be performed in an inert gas atmosphere. Thereby, formation of an oxide film can be suppressed. Since the structure is annealed by heating, the strength of the aluminum alloy base material may be lower than the strength of the joint interface. Therefore, in order to increase the strength of the joint as a whole, solution treatment and aging treatment may be further performed after joining, depending on the type of aluminum alloy.

In the metal joint member 10 according to this embodiment, a magnesium alloy member 12 and an aluminum alloy member 14 are joined via an intermediate layer 16a of titanium. A second diffusion layer (not shown) is formed, and metallurgically and integrally joined with high strength together with an anchor effect due to plastic flow. With this metal joint member 10, it is possible to form a composite metal product that is lightweight and has high corrosion resistance and mechanical strength. Alternatively, it can also be used as a surface modification technology for coating the surface of lightweight aluminum alloys and magnesium alloys with titanium, which is more excellent in corrosion resistance and wear resistance. In this way, bonding and surface modification become possible as well as molding. As a result, it can be applied to the chassis and frame of automobiles, other various structural parts, and forged parts such as suspension parts. It is applicable to metal products.

Furthermore, according to the method of manufacturing the metal-bonded member 10 according to this embodiment, the magnesium alloy member 12 and the aluminum alloy member 14 are subjected to impact pressure through the titanium insert member 16 using a press machine, a single-axis actuator, or the like. Just by performing it, it is possible to join with high strength, it is easy to manufacture, it has high productivity like conventional resistance welding, and it can handle dissimilar materials. In particular, any pressing device or heating device can be used, and an appropriate pressing device, other pressure device, or heating device can be used in accordance with the metal product to be manufactured.

Next, an apparatus for carrying out the metal joining method of the present invention will be described below. The metal bonding apparatus of this embodiment is preferably a mechanical press apparatus such as an AC servo press apparatus, which is a mechanical pressure apparatus, and has good productivity. A metal bonding apparatus 20 using an AC servo press will be described below with reference to FIG. The metal bonding apparatus 20 has a bolster 22 which is a supporting portion structured to allow plastic deformation of the metal material and a supporting jig (not shown), and applies a predetermined impact to the metal material to be bonded which is set and held by the supporting portion. A mechanical stress that applies a load to cause plastic flow at the interface where the metal materials are in contact with each other, increases the area of the interface, and forms a diffusion layer in which atoms of at least one metal material on the interface diffuses from the other metal material. An AC servo press device 24 is provided as a pressure device. Further, the AC servo press device 24, which is a mechanical pressure device, includes a slide 26 which is a reciprocating movable portion, a pressure jig (not shown), and an AC (not shown) which applies force to the movable portion to perform a pressure operation. It has a drive part such as a servomotor, and the drive part operates the movable part, and the metal material to be joined is sandwiched between the support part and the movable part to apply pressure to the metal material, thereby joining the metal materials together. .

In the AC servo press device 24 shown in FIG. 2, a slide 26 is provided in the center of a body frame 21 so as to be vertically movable, and a bed 28 fixed to the body frame 21 is positioned below the slide 26 to face it. , a bolster 22 is installed on the bed 28 . A control panel 30 is provided on the front side of the body frame 21 , and a control device 32 connected to the control panel 30 is provided on the side of the body frame 21 .

In the AC servo press device 24, a slide 26 is driven up and down by an AC servo motor (not shown), and a pressing jig is attached to the lower end of the slide 26 to press the metal materials to be joined to generate plastic flow. A mechanism for driving the slide 26 by an AC servomotor is a known mechanical mechanism, and the descending speed of the slide 26 is preferably 100 mm/s or more, and presses with a desired impact force. The bolster 22 as a support portion and a support jig (not shown) and the slide 26 as a movable portion and a pressure jig (not shown) are configured to allow plastic deformation of the metal materials to be joined. A metal material is clamped by a tool and a pressurizing jig, and plastically deformed in the clamped state by an AC servo press device 24, which is a mechanical pressurizing device, to be joined together.

According to the metal bonding apparatus 20 of this embodiment, various metal materials such as aluminum members and magnesium members can be solid-phase bonded extremely efficiently, inexpensively, and with high strength as compared with welding or mechanical connection. can be done. The cycle time is equivalent to that of conventional resistance welding, and it can also be used to join various dissimilar materials, which were difficult with resistance welding, and to join aluminum with low electrical resistance. Moreover, the shape of the joining portion does not matter, and it can be applied to many metal products. Furthermore, it can also be applied to surface modification applications.

Next, another type of metal bonding apparatus for carrying out the metal bonding method of the present invention will be described with reference to FIG. The metal bonding apparatus 30 of this embodiment performs metal bonding using a robot gun type press device 32 which is a mechanical pressure device. The press device 32 includes a fixed pin 34, which is a supporting portion structured to allow plastic deformation of the metal material, and a support frame 36 to which the fixed pin 34 is fixed at one end. The support frame 36 is formed in a C-shape, and has a movable pin 38 at the other end for pressing against the fixed pin 34 . The movable pin 38 is provided so as to be able to reciprocate, and a driving section 40 that applies a pressure force to the movable pin 38 to perform a pressurizing operation is provided above the support frame 36 . The drive unit 40 reciprocates the movable pin 38 with a motor, hydraulic pressure, or air pressure. The drive unit 40 actuates the movable pin 38 in a protruding direction to face the fixed pin 36, which is a support portion, with the metal material to be joined sandwiched therebetween, and applies a predetermined impact load to the metal material to be joined, thereby joining the metal materials together. plastic flow is generated at the interface.

A robot gun type press device 32 shown in FIG. 3 has a support frame 36 provided with a fixed pin 34 and a movable pin 38 attached to an arm 44 of an articulated robot 50 via a pivot shaft 42 . The articulated robot 50 has an arm 44 and an arm 46 , the arms 44 and 46 are connected by a pivot shaft 48 , and the base end of the arm 48 is connected to the robot main body drive section 54 via a pivot shaft 52 . installed. The arm 46 is provided so as to be swingable by the robot main body driving section 54 . Further, a driving motor 56 is provided on the rotating shaft 42 of the multi-joint robot 50, and a driving motor 58 is provided on the rotating shaft 48, and the supporting frame 36 and the arm 44 are respectively formed to be able to swing. there is

According to the metal bonding apparatus 30 of this embodiment, it can be used in place of a gun-type spot welding robot or the like similar to the conventional resistance welding method, and can more easily bond metal materials. In addition, while increasing the area of the joint interface between the metal materials , at least one of the metal materials at the interface forms a diffusion layer in which the atoms of the other metal material are diffused to join the metal materials. It is possible to carry out construction with the same joint strength at a reduced cost. Furthermore, various metal materials such as aluminum members and magnesium members can be easily joined.

Next, a metal member joining system that implements the metal joining method of the present invention will be described below with reference to FIGS. 4 and 5. FIG. In the metal member joining system 60 of this embodiment, solid-phase metal materials composed of the magnesium alloy member 12, the aluminum alloy member 14, and the titanium insert member 16 are superimposed on each other, and the above-described metal joining apparatuses 20, 30 and the like are used. As a pre-process, a metal member supply device 62 is provided for supplying the magnesium alloy member 12, the aluminum alloy member 14, and the titanium insert material 16 to be joined to the metal joining devices 20 and 30. . The metal member supply device 62 can be appropriately selected from a transport conveyor, an automatic machine, a supply robot, and the like. Further, a metal member unloading device 64 is provided for unloading the metal bonding members bonded by the AC servo press device 24 or the robot gun type press device 32, which is a mechanical pressure device of the metal bonding devices 20 and 30. be. The metal member carry-out device 64 can also be appropriately selected from a carry-out conveyor, an automatic machine, a carry-out robot, and the like.

This metal member joining system 60 is installed in a manufacturing line for metal products such as aluminum and magnesium. may be used. For example, the welding part of a conventional resistance welding robot may be replaced with this metal joining apparatus. A preheating device 66 is provided beside the mechanical pressure devices 20 and 30 . The preheating device 66 may be one that heats by laser light, electromagnetic induction, flame, or the like, for example.

Further, a plurality of this metal bonding apparatus may be arranged in a manufacturing line of metal products, and metal members may be sequentially carried in and out of the plurality of metal bonding apparatuses by a metal member supply device and a metal member unloading device. good. For example, as shown in FIG. 5, a preheating device 66, a metal member supply device 62, metal bonding devices 20 and 30, and a metal member unloading device 64 may be provided in series to sequentially perform predetermined processing.

According to the metal member joining system of this embodiment, it is possible to replace conventional joining of various metal materials by welding, etc., for example, with a cycle time equivalent to that of conventional resistance welding, and it was difficult with resistance welding. It can also be applied to the joining of various dissimilar materials and the joining of aluminum with low electric resistance. In the manufacturing process of various products, the joining process of metal members can be performed with a simple apparatus and energy saving, and the space can be saved and the cost can be greatly reduced.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. The metal joint member 10 is formed by joining a magnesium alloy member 12 and an aluminum alloy member 14 through an intermediate layer 16a made of a titanium insert material 16 under heating. Alternatively, depending on the metals to be joined and the application, the joining process may be performed without using the insert material 16 . Further, as the insert material, particulate titanium may be used instead of the sheet form.

Moreover, the metal bonding apparatus of this embodiment may bond aluminum or aluminum alloys by the same process and apparatus as described above. In this case, no insert material is required. For example, even aluminum alloys can be applied to the joining of various members such as the space frame structure of automobiles made of various different members such as rolled materials, extruded materials, cast materials and forged materials that have different compositions and mechanical properties. .

Furthermore, the metal bonding apparatus of this embodiment may bond iron and other metals as other materials by the same process and apparatus as described above. For example, it can be applied to join structural steel materials and aluminum alloy extruded materials in space frames of automobiles and the like.

In addition, the metal bonding apparatus and the metal member bonding system can be of any suitable type as long as they are capable of carrying out the above-described metal-made convenient method, and the method of driving the apparatus does not matter.

EXAMPLES Examples of the present invention will be described below together with drawings showing measurement results. Here, a magnesium alloy member 12 having a shape shown in FIG. It was joined by the manufacturing method of As a result, the magnesium alloy member 12 and the aluminum alloy member 14 were integrally joined at the joint interface through the intermediate layer 16a. The dimensions of the magnesium alloy member 12 and the aluminum alloy member 14 shown in FIG. 6 in this embodiment are cylindrical members each having a diameter of 50 mm and a height of 50 mm in the state shown in FIG. 6(a) before pressing. board. The insert material 16 is a pure titanium sheet material having a diameter of 50 mm and a thickness of 1 mm. In the following examples, the dimensions after the joining process are plastically deformed into the shape shown in FIG.

The bonding processing conditions of this example were carried out at a preheating temperature of 380°C. In addition, pressurization is performed by impact using an AC servo press device, which is a mechanical press device (formation takes about 0.4 seconds from the start of deformation to the bottom dead center), and the holding pressure at the bottom dead center is 200 MPa. The time was set to 1 second. The cycle time (top dead center→bottom dead center→top dead center) in this case is about 2.8 seconds.

As shown in FIGS. 7(a) and 7(b), the produced metal-bonded member 10 has an oxide film removed by plastic flow at the interface between the magnesium alloy member 12 and the pure titanium insert material 16, and the metal material is removed on the new surface. A first diffusion layer 17 in which atoms are well diffused is formed, and a high-strength bond is formed through an intermediate layer 16a of pure titanium. The thickness t1 of the first diffusion layer 17 at this time is formed as an extremely thin metal reaction layer of about 5 nm. Similarly, at the interface between the aluminum alloy member 14 and the pure titanium insert material 16, the oxide film is removed by plastic flow, and a second diffusion layer (not shown) is formed by diffusing atoms of the metal material on the new surface, forming an intermediate layer of pure titanium. It is joined with high strength via 16a. The thickness of the second diffusion layer (not shown) at this time is also formed as a thin metal reaction layer on the order of nanometers.

In the metal-bonded member 10 of this embodiment, the portion to be fractured by the tensile test is the interface portion between the magnesium alloy member 12 and the pure titanium intermediate layer 16a. FIG. 8(a) shows a scanning electron microscope compositional image of the fracture surface on the pure titanium side. At the bonding interface, the white-looking pure titanium intermediate layer 16a of the first diffusion layer 17 intervenes with the black-looking magnesium of the magnesium alloy member 12, and it can be seen that the two materials are joined with high strength. As shown in the enlarged scanning electron microscope composition image of FIG. 8(b), dimples, which are evidence of ductile fracture, are formed in the white-looking pure titanium intermediate layer 16a of the first diffusion layer 17. It can be seen that good materials are joined with high strength.

FIG. 9 shows the results of a test on the effect of preheating temperature conditions on the tensile strength of the metal joint member 10 of this example. The columnar members of the magnesium alloy member 12 and the aluminum alloy member 14 were jointed at four preheating temperatures of 250°C, 320°C, 380°C and 420°C via a pure titanium insert material 16 (thickness 1 mm). . Pressurization was performed using an AC servo press machine, which is a mechanical press device that operates at high speed, and was carried out with a bottom dead center holding time of 1 second under pressure control of 200 MPa. From this, it was found that the preheating temperature of the joining material should be 300° C. or more when joining the magnesium alloy member 12 and the aluminum alloy member 14 . In particular, considering appearance quality, it was found that it is desirable to process at a temperature of about 380° C. where burrs and cracks do not occur.

Next, FIG. 10 shows the results of a test on the effect of the thickness of the insert material 16 before processing (pressurization) on the tensile strength of the metal joint member 10 of this example. From the test results, when the insert material 16 was not used (0 mm), the magnesium alloy member 12 and the aluminum alloy member 14 could not be joined. In both cases, it was found that the metal joining member 10 has sufficient tensile strength. The fracture surface at this time was the interface portion between the magnesium alloy member 12 and the pure titanium intermediate layer 16a regardless of the thickness of the insert material 16 . Therefore, it was found that the insert material 16 of 1.0 mm or less, especially 0.3 mm, which is highly productive from the viewpoint of cost, etc., can provide good bonding strength.

Next, FIG. 11 shows the results of a test on the effect of pressure holding time at the bottom dead center on the tensile strength of the metal joining member 10 of this example. From the test results, it was found that the tensile strength tends to increase if the pressurization holding time at the bottom dead center is lengthened, but sufficient tensile strength can be obtained even with 0.1 second. It was found that this joining process can be efficiently performed in a sufficiently short cycle time equivalent to conventional resistance welding by using a mechanical press such as a servo press or a single-axis actuator.

Next, FIG. 12 shows the test result of the pretreatment of the joint surface of the metal joint member 10 of this example. This is the effect of the bonding surface polishing treatment before bonding on the tensile strength. From this test result, although the tensile strength at the joint member interface shows a tendency to improve when the joint surface is polished, all of the magnesium alloy member 12, the pure titanium insert member 16, and the aluminum alloy member 14 It was found that even if unpolished, the tensile strength was almost the same as that of the pre-polished one without a significant decrease in strength. This is because the plastic flow at the joint interface due to the impact load increases the area of the interface, breaks the oxide film at the interface, and creates a new surface. It is thought that this is because a very thin reaction phase with high strength was generated because the retention time of was extremely short. Therefore, although it is a diffusion reaction, pre-polishing treatment for the bonding process is basically unnecessary for each base material and insert material. higher. In particular, in this field, it is thought that this method can be used as a high-speed solid-phase joining method that can be used to join dissimilar materials, which will become more necessary in the future, in place of conventional resistance welding.

10 metal bonding member 12 magnesium alloy member 14 aluminum alloy member 16 insert material 16a intermediate layer 17 first diffusion layer 18 second diffusion layer 20 metal bonding device 21 body frame 22 bolster 24 servo press device 26 slide 28 bed

Claims (10)

A mechanical pressure device is used to apply a predetermined impact load to the metal materials in a solid phase that are superimposed on each other and mechanically pressurized to cause plastic flow at the interfaces where the metal materials are in contact with each other. and forming a diffusion layer in which atoms of the other metal material are diffused into at least one of the metal materials at the interface to integrally join the metal materials ,
The metal material is a state in which materials are used in which the bonding surface is not polished, and the metal material is heated to a temperature that facilitates the plastic flow of the metal material and does not generate a liquid phase even during the pressurization. At, the pressurization is performed,
The holding time of the pressurization is 3 seconds or less,
The pressurization causes the surfaces of the metal materials to contact each other, the oxide film is broken by plastic flow, and a new surface appears on the joint surface, and the joint area between the surfaces increases to form the diffusion layer, A metal joining method, characterized in that the metal materials are joined together. The metal joining method according to claim 1 , wherein the temperature that facilitates plastic flow is 250°C to 450°C . 3. The metal joining method according to claim 2 , wherein the pressurization pressure is 100 MPa to 700 MPa . 2. The method of joining metals according to claim 1 , wherein said diffusion layer is on the order of nanometers . 4. The metal joining method according to claim 2 , wherein said metal materials are different metals . 5. The metal joining method according to claim 4 , wherein the metal material is a forged material to which forging is applied . 5. The method of joining metals according to claim 3 , wherein the pressure is maintained for 1 second or less . 6. The metal joining method according to claim 5, wherein said metal materials are aluminum or an aluminum alloy and magnesium or a magnesium alloy. 4. The metal joining method according to claim 2, wherein the metal material is aluminum or an aluminum alloy. 4. The metal joining method according to claim 2, wherein the metal materials are magnesium or magnesium alloys.

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