JP2007136497A - Method of joining different kind of materials - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of joining different kinds of materials, a method having extensive welding conditions and making high strength welding possible, even in aluminum/iron spot welding. <P>SOLUTION: In lap resistance welding using aluminum and iron, an adhesive for joining different kinds of materials is interposed between the joining surfaces. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a dissimilar material joining method that is excellent in corrosion resistance even in the joining of dissimilar materials such as aluminum and iron that generate electrolytic corrosion.

  Conventionally, structural adhesives used for the body of automobiles and hemming parts of lids are mainly made of epoxy resin, and adhesives containing plasticizers, fillers (calcium carbonate, etc.) and other additives are used. (For example, refer to Patent Documents 1 to 5.) In spot welding of the same material such as iron and iron, or aluminum and aluminum, a well bond structure in which these adhesives are sandwiched between flanges is used, and by sandwiching the adhesive, strength, rigidity and Has improved corrosion resistance.

JP 05-156227 A Japanese Patent Laid-Open No. 06-108028 Japanese Patent Laid-Open No. 08-206845 JP 11-61072 A JP 2004-168928 A

  However, in the joining of dissimilar materials such as aluminum / iron, the flange portion where the contact of the dissimilar metal occurs with electric corrosion and crevice corrosion, and has a problem that the corrosion resistance is inferior to the welding of the same metal. It was. When such a dissimilar material bonding is used in an automobile or the like, the spot will be peeled off immediately by electrolytic corrosion, so that it is necessary to use a well bond structure in which an adhesive is applied to insulate the bonding portion.

  In addition, in spot welding of aluminum / iron dissimilar materials, when the flange is filled with the conventional spot welded adhesive, corrosion resistance can be ensured, but the welding mechanism is diffusion bonding, so the adhesive must be sandwiched. Has a great influence on weldability. Thereby, there existed a problem of causing the strength fall by generation | occurrence | production of joining failure, generation | occurrence | production of a sputter | spatter, a conduction failure, etc.

  Accordingly, the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a dissimilar material joining method that allows a wide range of welding conditions and high strength welding even in aluminum / iron spot welding.

  The dissimilar material joining method of the present invention is characterized in that an adhesive for dissimilar material joining is sandwiched at the interface of the joint in the overlap resistance welding using aluminum and iron. The adhesive for bonding dissimilar materials in the present invention is composed of an epoxy resin, a curing agent, and a filler, and in particular, the content of the filler is reduced from the conventional structural adhesive.

  According to the present invention, since the adhesive for dissimilar material bonding has not only the sealing performance but also the strength due to the bonding, by using this adhesive for bonding dissimilar materials, welding conditions can be obtained even in aluminum / iron spot welding. However, it is possible to perform high-strength welding that does not decrease the spot strength, and provides a sealing effect around the dissimilar material joint, thereby suppressing electrolytic corrosion. As described above, since high-strength welding is possible, the aluminum to be joined is not limited to the surface-treated one.

  As a result, even when dissimilar joints such as aluminum and iron are overlapped and resistance welded, it becomes possible to construct with general-purpose equipment, and in automobile manufacturing, the vehicle body can be partially replaced with aluminum material. It can be expected to significantly reduce the weight, improve fuel efficiency, and improve the performance of automobiles. Also, it can be easily applied to transportation fields such as railway vehicles, machine parts, home appliances, and household goods outside the automobile field. There is an effect.

Hereinafter, preferred embodiments of the dissimilar material joining method of the present invention will be described.
In the dissimilar material joining method of the present invention, overlap resistance welding is performed in a state where an adhesive for dissimilar material joining is sandwiched at the interface between aluminum and iron. Here, the adhesive for bonding dissimilar materials in the present invention is an adhesive composed of an epoxy resin, a curing agent, and a filler, and specifically, an adhesive obtained by reducing the filler from a conventional structural adhesive. It is done. The filler in the present invention includes calcium carbonate, calcium oxide, magnesium oxide, zinc oxide, lead oxide, silica, talc, carbon, anhydrous silicic acid, bentonite, metal powder, resin powder, glass powder, and glass fiber. The thing which consists of at least 1 or more is mentioned.

  Moreover, in this invention, it is preferable that 1-32 weight% of fillers are contained. When the content of the filler is less than 1% by weight, problems occur in the sag and hygroscopicity in the line. Silica is suitable for preventing dripping and calcium oxide is suitable for preventing moisture absorption. On the other hand, when the content of the filler exceeds 32% by weight, the bonding strength of the dissimilar material bonded structure decreases.

  Furthermore, the dissimilar material joint structure of the present invention is characterized in that an adhesive for dissimilar material bonding is sandwiched at the interface of the joint in the overlap resistance welding using aluminum and iron. Moreover, in the dissimilar-material joining structure of this invention, it is preferable that the junction interface which overlap | superposed aluminum and iron forms the weld bond structure, and according to this, the further strength improvement is achieved.

Hereinafter, the dissimilar material joining method of the present invention will be specifically described with reference to Examples and Comparative Examples.
1. Preparation of Adhesive for Dissimilar Materials The structural adhesive (trade name: # 1085) manufactured by Sunstar Giken Co., Ltd. was used as the adhesive 7 for the comparative example, and as shown in Table 1, the blending amount of each filler was reduced. Were used as adhesives 1 to 6 for Examples. Contrary to the adhesive for the examples, the adhesive 8 for the comparative example was obtained by increasing the blending amount of the filler.

2. Manufacture of aluminum / iron dissimilar bonded structure 100 mm long, 40 mm wide, 1.0 mm thick alloyed hot dip galvanized (GA) steel plate (trade name: JAC270E, manufactured by Nippon Steel Corporation) or hot dip galvanized (GI) ) Apply each adhesive shown in Table 1 on a steel plate (trade name: SGCC-Z12, manufactured by Nippon Steel Co., Ltd.) to a thickness of 100 μm in a range of 40 × 40 mm ² , and sandwich this adhesive. In addition, a 5000 series aluminum member (trade name: A5182, manufactured by Nippon Steel Corporation) or a 6000 series aluminum member (trade name: 6K21, manufactured by Kobe Steel, Ltd.) having a length of 100 mm, a width of 40 mm, and a thickness of 1.0 mm. Using the pressurized AIR type inverter welding machine (trade name: YR-100CHJ120, manufactured by Matsushita Electric Industrial Co., Ltd., chip: DR6 type), the stacked laminate is added. : 150 kgf and the current value: perform overlay resistance welding at 10 kA, to prepare each aluminum / iron dissimilar materials bonded structure using dissimilar materials bonded method of Examples and Comparative Examples.

3. Evaluation For each aluminum / iron dissimilar bonded structure produced as described above, the bonding strength was measured at a pulling rate of 5 mm / min using an Instron 10 ton tensile tester in accordance with JIS 3136. . These results are shown in Table 2 and FIG.

  As is apparent from Table 2 and FIG. 1, it was shown that the aluminum / iron dissimilar material bonded structure using the dissimilar material bonding method of the present invention can ensure sufficient strength even with an adhesive interposed therebetween. On the other hand, in the aluminum / iron dissimilar material bonded structure using the dissimilar material bonding method of the comparative example when the filler content exceeds 32% by weight, the target fusion bonding strength may not be achieved. Indicated. In addition, although experimental data is not shown in the present specification, in the aluminum / iron dissimilar material bonded structure using the dissimilar material bonding method of the comparative example when the filler content is less than 1% by weight, the adhesive by moisture absorption It has become clear that the quality of the material has deteriorated, and the viscosity during construction is small, causing inconveniences such as dripping, poor handling (workability), and problems in industrial implementation. It was.

It is a diagram which shows the relationship between the amount of fillers, and joint strength in the aluminum / iron dissimilar material joining structure using the dissimilar material joining method of this invention.

Claims (4)

  In the overlap resistance welding using aluminum and iron, the dissimilar material joining method characterized by sandwiching the dissimilar material bonding adhesive at the joint interface.   The said different material joining adhesive agent consists of an epoxy resin, a hardening | curing agent, and a filler, The said filler is contained 1-32weight%, The different material joining method of Claim 1 characterized by the above-mentioned.   The filler is at least one of calcium carbonate, calcium oxide, magnesium oxide, zinc oxide, lead oxide, silica, talc, carbon, anhydrous silicic acid, bentonite, metal powder, resin powder, glass powder, and glass fiber. The dissimilar material joining method according to claim 2, wherein:   In the overlap resistance welding using aluminum and iron, a dissimilar material joint structure characterized by sandwiching a dissimilar material bonding adhesive at the joint interface.

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