JP2006224147A - Method for joining different materials and filler metal therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for joining different materials, by which method, aluminum or an aluminum alloy material can be easily joined with a steel material at a low cost, and a joint having an high joining strength can be obtained, and to provide a filler metal therefor. <P>SOLUTION: The aluminum based material 2 is overlapped on the steel material 1 having aluminum based coating layers 4 composed of aluminum or an aluminum alloy on the surface of the steel material 1 at their edge portions in such a manner that the surface having the aluminum based coating layers 4 formed thereon comes on the side of the aluminum based material 2. In this case, the aluminum based material 2 is arranged so as to come on the side of a torch 5. Then, the overlapped portion is welded by the overlapped fillet welding by the AC metal inert gas (MIG) arc welding using the filler metal 6 containing 1.5 to 6.0 mass% of Si and the balance being Al with unavoidable impurities. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a different material joining filler material used when welding aluminum or an aluminum alloy material and a steel material, and a dissimilar material joining method using this filler material, and in particular, an aluminum surface having aluminum or an aluminum alloy. The present invention relates to a different material joining filler material and a different material joining method used when welding a coated steel material on which a system coating layer is formed.

Recently, in order to reduce the weight of various structural materials of automobiles, instead of steel materials conventionally used, some of them are made of aluminum or aluminum alloy materials (hereinafter collectively referred to as aluminum-based materials). A composite structure using the same is also used. In order to obtain such a composite structure material, it is necessary to join a steel material and an aluminum-based material, but in the dissimilar material joining of the aluminum-based material and the steel material, suppressing the formation of brittle intermetallic compounds, It is difficult to stably weld the steel material so as not to melt it. For example, when a fusion welding method such as Tungsten Inert Gas (TIG) welding or laser welding, which is generally used as a method for joining the same kind of materials, is applied to the joining of an aluminum material and a steel material, the aluminum material Brittle Al—Fe-based intermetallic compounds such as FeAl ₃ and Fe ₂ Al ₅ are formed at the interface between the steel and the steel, thereby significantly reducing the bonding strength between the aluminum-based and the steel. Thus, it is difficult to apply a general joining method used when joining the same kind of materials to the joining of metal materials of mutually different materials. For this reason, an aluminum-based material and a steel material are combined. There is a demand for the development of a method for joining dissimilar materials that can be satisfactorily joined.

  Conventionally, as a dissimilar material joining method between an aluminum-based material and a steel material, brazing using an aluminum-based brazing material is generally used (see, for example, Patent Documents 1 and 2 and Non-Patent Document 1). In the brazing method described in Patent Document 1, a brazing material having a melting point between the melting point of the aluminum-based material and the melting point of the steel material is used, and the steel material and the brazing material are heated to a temperature equal to or higher than the melting point of the brazing material, The parts other than the vicinity of the bonding interface in the aluminum-based material are brazed while being kept below the melting point of the aluminum-based material. Moreover, in the joining method described in Patent Document 2, a flux-containing brazing material composed of a compacted body of a brazing material component and a flux component is used to braze the aluminum-based material and the steel material. Further, Non-Patent Document 1 discloses a brazing method by laser brazing using a semiconductor laser.

  There is also a method of joining an aluminum-based material and a steel material by spot welding or MIG (Metal Inert Gas; MIG) welding instead of brazing (see Non-Patent Document 2, for example). In the dissimilar material joining method described in Non-Patent Document 2, a pure aluminum plate and a coating layer are formed by MIG welding using a flux cored wire having an effect of removing an oxide film as an electrode wire and using a DC pulse power source. Not joined with bare steel plate.

  Furthermore, a different material joining method using a laser roll has also been proposed (see Patent Document 3). In the dissimilar material joining method described in Patent Document 3, after heating only the first metal plate by laser irradiation, the heating portion of the first metal plate is pressed and brought into close contact with the second metal plate by a pressure roller, and plastic deformation is performed. By giving, metal plates of different materials are joined to each other.

JP 7-148571 A JP 10-314933 A Japanese Patent No. 3535152 Yu Uo, 3 others, “Fundamental examination of weldability with aluminum brazing-Dissimilar joining of aluminum alloy and steel material by laser brazing (1st report)”, Journal of the Japan Welding Society, 2004, Vol. 22, No. 2, p. 315-322 Osaka University Institute of Bonding Science, Dissimilar Materials Joining Study Group, “Survey Research on Molten Process Aluminum / Steel Dissimilar Materials Joining Technology,” FY 2002 Results Report, March 2003, p. 75-93

  However, the conventional techniques described above have the following problems. First, the dissimilar material joining method by brazing as described in Patent Documents 1 and 2 and Non-Patent Document 1 requires that a brazing material be inserted between the aluminum-based material and the steel material. There is a problem that it becomes high.

  Further, since spot welding is not line bonding but point bonding, when different materials are bonded by this method, a gap is formed in the portion between the bonding points so that liquid or gas can pass therethrough. There is a problem that it cannot be sealed. In addition, since spot welding cannot be performed from one side, electrodes must be arranged on both sides of the overlapped portion of the materials to be joined, i.e., both sides to be joined. is there.

  Furthermore, the dissimilar material joining method by DC pulsed MIG welding as described in Non-Patent Document 2 generally has a DC reverse polarity in which the electrode is positive (+) and the base material is negative (-). In order to suppress melting into the material, the current must be squeezed, which makes the arc unstable, makes it easier for spatter to occur, and reduces the cleaning action to remove the oxide film. There is a problem. Among these problems, the latter cleaning action can be improved by using a flux cored wire. However, when using a flux cored wire, the construction condition range is narrower than using a solid wire. Therefore, there is a limit to the effect of suppressing the occurrence of the former spatter. In addition, the flux cored wire is a special wire for joining aluminum-based materials, and is expensive, so that there is a problem that the manufacturing cost increases.

  Furthermore, the dissimilar material joining method using a laser roll described in Patent Document 3 has a problem in that a material to be joined, that is, an aluminum-based material and a steel material must be pressed by a roll, and a large-scale apparatus is required.

  The present invention has been made in view of such problems, and can join aluminum or an aluminum alloy material and a steel material easily and at low cost, and can be used for joining different materials that can provide a joint with excellent bonding strength. It aims at providing the filler material and the dissimilar material joining method.

  The filler material for joining different materials according to the first invention of the present application is a filler used for joining different materials for welding aluminum or an aluminum alloy material and a steel material provided with an aluminum-based coating layer made of aluminum or aluminum alloy on the surface. The material is characterized by containing Si: 1.5 to 6.0% by mass and the balance being made of Al and inevitable impurities.

  In the present invention, similar to the case of welding aluminum-based materials, since the filler metal can be in the form of a solid wire, no special consideration and new equipment are required during welding. Is transferred as droplets as a consumable electrode, so there is no need to insert a brazing material. Thereby, an aluminum-type material and a steel material can be joined easily and at low cost. In addition, since the filler material of the present invention has added Si and optimized the content thereof, the melting point is low, and it is difficult to produce an intermetallic compound that lowers the bonding strength. Good compatibility with ductility. As a result, a joint with excellent bonding strength can be obtained.

  This filler material may further contain Mg: 0.1 to 0.3% by mass. Thereby, while being able to suppress the growth of the intermetallic compound at the time of joining, the weld metal part can be further strengthened.

  The filler material for joining different materials according to the second invention of the present application is a filler used for joining different materials for welding aluminum or an aluminum alloy material and a steel material provided with an aluminum-based coating layer made of aluminum or aluminum alloy on the surface. The material is characterized by containing Mg: 2.0 to 3.5% by mass, the balance being made of Al and inevitable impurities.

  In the present invention, since the filler material can be in the form of a solid wire, special consideration at the time of welding, such as a flux cored wire, and the introduction of a new device are not required. Further, the filler material of the present invention has both functions of a brazing material and an electrode, and transitions into droplets during welding, so there is no need to insert a brazing material. As a result, aluminum or an aluminum alloy material and a steel material can be joined easily and at low cost. In addition, since the filler material of the present invention is added with Mg and the content thereof is optimized, the intermetallic compound that decreases the bonding strength despite the addition of Mg that is easily diffused. It is difficult to grow, and the compatibility between the strength and ductility of the weld metal part is good. As a result, a joint with excellent bonding strength can be obtained.

  Further, the above-mentioned filler material for joining different materials further comprises Mn: 0.1 to 0.3% by mass, Cr: 0.05 to 0.20% by mass and Zr: 0.1 to 0.2% by mass. One kind of element selected from the group may be contained. Thereby, since the intensity | strength and / or ductility of a weld metal part can further be improved, the joint strength can further be heightened.

  The dissimilar material joining method according to the third invention of this application uses Si: 1.5 to 6.0% by mass, the balance is made of Al and unavoidable impurities, and an aluminum or aluminum alloy material is used on the surface. It is characterized by welding a steel material provided with an aluminum-based coating layer made of aluminum or an aluminum alloy.

  In the present invention, since an aluminum-based material is welded to a steel material having an aluminum-based coating layer on the surface using an Al-Si-based filler material, an aluminum-based material that forms a molten metal, Both the aluminum-based coating layer and the filler material are formed of aluminum or an aluminum alloy, and the affinity between molten metals is excellent. In addition, since the Si content of the filler metal is optimized, the melting point of the filler metal is lowered, intermetallic compounds are less likely to be formed at the joint, and both the strength and ductility at the weld metal are favorable. Become. As a result, a joint having excellent bonding strength can be obtained. Furthermore, since the filler material has the functions of both a brazing material and an electrode, it is not necessary to insert a brazing material separately. Thereby, an aluminum-type material and a steel material can be joined easily and at low cost.

  In this dissimilar material joining method, in addition to the above-mentioned components, a filler material containing Mg: 0.1 to 0.3% by mass may be used. Thereby, since melting | fusing point of a filler material can be made lower, and also it can make it difficult to produce | generate an intermetallic compound in a junction part, and since it can make a weld metal part high-strength, joining strength is high. A particularly excellent joint can be obtained.

  The dissimilar material joining method according to the fourth invention of the present application uses Mg: 2.0 to 3.5% by mass, the balance is made of Al and inevitable impurities, the aluminum or aluminum alloy material, and the surface. It is characterized by welding a steel material provided with an aluminum-based coating layer made of aluminum or an aluminum alloy.

  In the present invention, an Al-Mg-based filler material is used to weld a steel material and an aluminum-based material provided with an aluminum-based coating layer on the surface, so that an aluminum-based material that forms a molten metal, Both the aluminum-based coating layer and the filler material are formed of aluminum or an aluminum alloy, and the affinity between molten metals is improved. In addition, since the Mg content of the Al-Mg-based filler material is optimized, it is difficult to grow to an intermetallic compound that lowers the bonding strength despite the addition of Mg that is easy to diffuse. In addition, the strength and ductility of the weld metal part can be improved in a well-balanced manner. As a result, a joint with excellent bonding strength can be obtained. In addition, since the filler material causes the brazing filler metal component to be transferred as a consumable electrode, there is no need to insert a separate brazing filler metal. Therefore, the aluminum-based material and the steel material can be joined easily and at low cost. be able to.

  In these dissimilar material joining methods, in addition to the above-described components, Mn: 0.1 to 0.3% by mass, Cr: 0.05 to 0.20% by mass, and Zr: 0.1 to 0.2% A filler material containing one element selected from the group consisting of mass% can also be used. Thereby, the intensity | strength and / or ductility of a weld metal part can be improved more, and joint strength can further be raised.

  According to the present invention, since the filler material can be in the form of a solid wire, aluminum or aluminum alloy material and steel can be joined easily and at low cost, and the components of the filler material can be optimized. Therefore, it is possible to reduce the melting point of the filler metal and to suppress the formation of brittle intermetallic compounds at the joint, and to improve both the strength and ductility of the weld metal part. Therefore, the joint strength of the joint can be improved.

  Hereinafter, the filler material according to the embodiment of the present invention will be specifically described with reference to the accompanying drawings. First, the filler material according to the first embodiment of the present invention will be described. The filler material of this embodiment is a filler material for joining different materials used when welding aluminum or an aluminum alloy material and a steel material provided with an aluminum-based coating layer made of aluminum or an aluminum alloy on the surface. . And the composition contains 1.5 thru | or 6.0 mass% of Si, and the remainder is Al and an unavoidable impurity. Hereinafter, the reason for the numerical limitation in the filler material of the present embodiment will be described.

Si content: 1.5 to 6.0 mass%
In order to form a dissimilar material joint by welding materials to be welded different from each other, for example, in the case of arc welding, the temperature from the temperature at which the weld metal part becomes a completely solid phase to the room temperature at the high temperature of welding immediately after passing through the arc. It is necessary to absorb the difference in heat shrinkage between the weld metal part and the material to be welded by welding deformation and residual stress. For this reason, as the filler material used for dissimilar material joining, a material having a small difference between the temperature at which it becomes a completely solid phase and room temperature, that is, a material having a solidus temperature as low as possible is preferable. In the material, Si is added to lower the melting point. In addition, the Si-containing Al-Si-based alloy has a characteristic that the thermal expansion coefficient is small compared to other aluminum alloys, and the filler material made of this Al-Si-based alloy is made of an aluminum-based material, a steel material, and the like. By arrange | positioning between, the effect which absorbs the heat shrink difference between these is also acquired.

  However, when the Si content is less than 1.5% by mass, the melting point is not sufficiently lowered, and the melting point of the filler material becomes too high. On the other hand, when Si content exceeds 6.0 mass%, the bending performance of a weld metal part will fall. In a tensile shear test when evaluating a lap fillet joint that is frequently used for automobiles, an element of rotational bending enters due to an axial deviation. For this reason, when the bending performance of a weld metal part falls, the joint strength of a dissimilar material joined body, ie, joint strength, will fall. Therefore, the Si content is 1.5 to 6.0 mass%.

In addition, when a dissimilar material joined body is applied to an automobile material or the like, since a coating baking process or the like is performed in a subsequent process, the dissimilar material joined body is exposed to a temperature condition of about 175 to 200 ° C. When the filler material of this embodiment is used, it is considered that the growth of the intermetallic compound at the joint is not promoted under such temperature conditions. However, when Mg is contained in the aluminum-based material, a mixture of the filler material and the aluminum-based material generates a Mg ₂ Si compound, and further, when exposed to the above temperature condition, The growth of the Mg ₂ Si compound may be promoted. The brittle Mg 2 _Si compound junction to grow, there is a possibility that impair the ductility of the joint. In order to suppress the growth of the Mg ₂ Si compound in such a joint, it is desirable that the Si content of the filler material be 3.5% by mass or less.

  In the filler material of the present embodiment, since it can be in the form of a solid wire, similar to the filler material used when joining aluminum-based materials, special considerations and introduction of new equipment during welding are required. This filler material is not necessary, and can be used as a brazing material by dropping and transferring as a consumable electrode. Therefore, it is not necessary to insert a brazing material separately. For this reason, an aluminum material and a steel material can be joined easily and at low cost. Moreover, since the filler material of this embodiment has optimized the Si content, the melting point is low, and further, an intermetallic compound that lowers the bonding strength is not easily generated, and both the strength and ductility of the weld metal part are both produced. It is good. For this reason, a joint with excellent bonding strength can be obtained.

  Next, the filler material according to the second embodiment of the present invention will be described. The filler material of this embodiment is made of aluminum or an aluminum alloy material and a steel material provided with an aluminum-based coating layer made of aluminum or an aluminum alloy on the surface, like the filler material of the first embodiment described above. It is a filler metal for joining different materials used when welding. And the composition contains 2.0 to 3.5 mass% of Mg, and the balance is Al and inevitable impurities. Hereinafter, the reason for the numerical limitation in the filler material of the present embodiment will be described.

Mg: 2.0 to 3.5% by mass
In the filler material of this embodiment, Mg is added in order to achieve both the strength and ductility of the weld metal part and improve the joint strength. However, when the Mg content is less than 2.0% by mass, sufficient joint strength cannot be obtained. On the other hand, when the Mg content exceeds 3.5% by mass, the strength of the weld metal part is improved, but the growth of a brittle intermetallic compound layer formed between the steel materials is promoted, and the joint strength and ductility are reduced. To do. Therefore, the Mg content is set to 2.0 to 3.5% by mass.

  Since the filler material of the present embodiment can be in the form of a solid wire, there is no need for special consideration and introduction of a new device at the time of welding unlike a rack scored wire, and both the brazing material and the electrode are used. Because of this function, brazing material is not necessary. As a result, the aluminum-based material and the steel material can be joined easily and at low cost. In addition, since the filler material of the present embodiment optimizes the Mg content, it suppresses the formation of intermetallic compounds that reduce the bonding strength despite the addition of Mg that is easy to diffuse. In addition, both the strength and ductility of the weld metal part can be improved. As a result, a joint with excellent bonding strength can be obtained.

  Next, a filler material according to a third embodiment of the present invention will be described. The filler material of this embodiment is provided with an aluminum or aluminum alloy material and an aluminum-based coating layer made of aluminum or an aluminum alloy on the surface, like the filler materials of the first and second embodiments described above. This is a filler metal for joining different materials used when welding steel materials. And the composition contains Si: 1.5 to 6.0 mass% and Mg: 0.1 to 0.3 mass%, with the balance being Al and inevitable impurities.

The filler material of this embodiment is obtained by adding Mg to the filler material of the first embodiment described above, and the reason for adding Si and the reason for limiting the numerical values are the same as those of the first embodiment described above. . In addition, since the Al—Si—Mg based filler material such as the filler material of the present embodiment causes a Mg ₂ Si or Mg ₂ Si—Si based eutectic reaction when the weld metal part melts and solidifies. Furthermore, the Al—Si based filler material such as the filler material of the first embodiment described above and the Al—Mg based filler material such as the filler material of the aforementioned second embodiment are more solid. The phase line temperature is low, and in order to produce moderate Mg ₂ Si, the joint strength is higher than that of the Al—Si based filler and Al—Mg based filler, and the strength after baking is also high. However, when the contents of Mg and Si increase, the growth of the Mg ₂ Si compound in the welded portion is promoted, and the ductility of the joint is impaired. Therefore, in the filler material of this embodiment, the upper limit of the Mg content is set to 0.3% by mass. Moreover, the addition effect mentioned above is not acquired as Mg content is less than 0.1 mass%. Therefore, the lower limit of the Mg content is 0.1% by mass.

In the filler material of the present embodiment, since it can be in the form of a solid wire, similar to the filler material used when joining aluminum-based materials, special considerations and introduction of new equipment during welding are required. It is not necessary, and it can be used as a brazing material by transferring to a drop as a consumable electrode. Therefore, a brazing material is also unnecessary, and an aluminum-based material and a steel material can be joined easily and at low cost. it can. Moreover, since both the Si and Mg are added to the filler material of the present embodiment, the melting point is lower than that of the filler material to which only one of them is added, and the bonding strength after baking is further increased. In addition, an appropriate amount of Mg ₂ Si can be generated in the weld metal part. As a result, it is possible to obtain an excellent joint that has high joint strength at the time of welding and that does not decrease the joint strength even after baking.

  Next, a filler material according to a fourth embodiment of the present invention will be described. The filler material of this embodiment is provided with an aluminum or aluminum alloy material and an aluminum-based coating layer made of aluminum or aluminum alloy on the surface, like the filler materials of the first to third embodiments described above. This is a filler metal for joining different materials used when welding steel materials. And the composition contains Si: 1.5 thru | or 6.0 mass% and Mn: 0.1 thru | or 0.3 mass%, and remainder is Al and an unavoidable impurity. The filler material of this embodiment is obtained by adding Mn to the filler material of the first embodiment described above. The reason for adding Si and the reason for limiting the numerical values are the same as those of the first embodiment described above. . Hereinafter, the reason for limiting the numerical value of the Mn content in the filler material of the present embodiment will be described.

Mn: 0.1 to 0.3% by mass
Mn has the effect of improving joint strength by solid solution strengthening. However, when the Mn content is less than 0.1% by mass, there is little solid solution strengthening and the effect of improving the joint strength cannot be obtained. On the other hand, if the Mn content exceeds 0.3% by mass, the bending characteristics of the weld metal part begin to deteriorate, and the tensile shear strength of the lap joint part decreases. Therefore, the Mn content is 0.1 to 0.3% by mass.

  Since the filler material of the present embodiment is added with an appropriate amount of Mn in addition to Si, the joint strength is further improved as compared with the filler material of the first embodiment in which only Si is added. Can do. The effects of the filler material of this embodiment other than those described above are the same as those of the filler material of the first embodiment described above.

  Next, a filler material according to a fifth embodiment of the present invention will be described. The filler material of the present embodiment is provided with an aluminum or aluminum alloy material and an aluminum-based coating layer made of aluminum or aluminum alloy on the surface, like the filler materials of the first to fourth embodiments described above. This is a filler metal for joining different materials used when welding steel materials. And the composition contains Mg: 2.0 to 3.5 mass% and Mn: 0.1 to 0.3 mass%, with the balance being Al and inevitable impurities. The filler material of this embodiment is obtained by adding Mn to the filler material of the above-described second embodiment, and the reason for adding Mg and the reason for limiting the numerical values are the same as those of the above-described second embodiment. The reason for adding Mn and the reason for limiting the numerical values are the same as in the fourth embodiment.

  Since the filler material of the present embodiment is added with an appropriate amount of Mn in addition to Mg, the joint strength can be improved as compared with the filler material of the second embodiment in which only Mg is added. . The effects of the filler material of this embodiment other than those described above are the same as those of the filler material of the second embodiment described above.

  Next, a filler material according to a sixth embodiment of the present invention will be described. The filler material of this embodiment is provided with an aluminum or aluminum alloy material and an aluminum-based coating layer made of aluminum or an aluminum alloy on the surface, like the filler materials of the first to fifth embodiments described above. This is a filler metal for joining different materials used when welding steel materials. And the composition contains Si: 1.5 to 6.0 mass%, Mg: 2.0 to 3.5 mass%, and Mn: 0.1 to 0.3 mass%, with the balance being Al and inevitable Impurities. The filler material of this embodiment is obtained by adding Mn to the filler material of the above-described third embodiment. The reason for adding Si and Mg and the reason for limiting the numerical values are the same as those of the above-described third embodiment. The reason for adding Mn and the reason for limiting the numerical value are the same as in the fourth embodiment.

  Since the filler material of this embodiment has added an appropriate amount of Mn in addition to Si and Mg, the joint is superior to the filler material of the third embodiment to which Si and Mg are added. Strength is obtained. The effects of the filler material of this embodiment other than those described above are the same as those of the filler material of the third embodiment described above.

  In the filler materials of the above-described fourth to sixth embodiments, Mn is added to the filler materials of the above-described first to third embodiments, respectively. You may add Cr or Zr further to the filler material of the 1st thru | or 3rd embodiment. Cr and Zr have the effect of refining crystal grains to improve the strength and ductility of the weld metal part and improve joint strength. However, when adding these, it is desirable that the content in the filler metal is Cr: 0.05 to 0.20 mass%, Zr: 0.1 to 0.2 mass%. When the Cr content is less than 0.05% by mass or the Zr content is less than 0.1% by mass, the effect of addition may not be obtained. On the other hand, when the Cr content exceeds 0.20% by mass or the Zr content exceeds 0.2% by mass, coarse recrystallization or coarse crystallized product is generated, resulting in a decrease in ductility, and the joint characteristics are reduced. May deteriorate.

  Moreover, as an unavoidable impurity contained in the filler metal of the first to sixth embodiments described above, for example, there are Fe and Cu.

  The shape of the filler material of the first to sixth embodiments is generally a wire shape or a rod shape, but the present invention is not limited to these, and is appropriately selected according to the welding method. be able to. Also, the welding method is not particularly limited as long as it uses a filler material, and is effective in various types of MIG welding such as DC MIG welding, DC pulse MIG welding, AC MIG welding, AC pulse MIG welding, and short-circuit transfer type MIG welding. can get. Furthermore, it is applicable not only to MIG welding but also to TIG welding, laser welding, and hybrid welding using these in combination.

  Next, as a seventh embodiment of the present invention, a method of joining an aluminum-based material and a steel material differently using the filler material of the first embodiment described above will be described. FIG. 1 is a perspective view showing a dissimilar material joining method according to the present embodiment, and FIG. 2 is a cross-sectional view showing a joint portion of a joint joined by dissimilar materials by the method shown in FIG. As shown in FIGS. 1 and 2, the dissimilar material joining method of this embodiment includes a steel material 1 and an aluminum-based material 2 containing 1.5 to 6.0 mass% of Si, with the balance being Al and inevitable. This is a method of joining by using, for example, MIG arc welding or the like using a filler material made of impurities.

  As the steel material 1 to be joined by the dissimilar material joining method of the present embodiment, for example, a mild steel material, a high-tensile steel material, a stainless steel material, or the like can be applied. Further, an aluminum-based coating layer 4 made of pure aluminum or an aluminum alloy is formed on the front and back surfaces of the steel material 1. Since such a coated steel material is manufactured by, for example, forming the aluminum-based coating layer 4 on both surfaces of the steel material 1 by hot dipping or thermal spraying, and then cutting out necessary portions by shearing or the like, The aluminum-based coating layer 4 is not formed.

  In the dissimilar material joining method of the present embodiment, first, the aluminum-based material 2 is disposed on the torch 5 side, that is, above the steel material 1, and its end portion is overlapped on the end portion of the steel material 1, and the overlap portion 3 is overlapped with the corner Construct a meat joint. After that, in this overlap portion 3, an AC arc is generated between the filler material fed from the torch 5, that is, the welding wire 6, and the material to be welded (steel material 1 and aluminum-based material 2). Thereby, in the cycle in which the welding wire 6 as the electrode wire serves as an anode, the surface oxide film of the aluminum-based coating layer 4 is removed by the arc cleaning action, and further, the aluminum-based coating layer 4 and the aluminum-based material are generated by arc heat. The two ends melt. Then, the overlapping portion 3 is overlapped and welded by moving the torch 5 along the ends of the steel material 1 and the aluminum-based material 2 while generating an arc.

  Thus, in the dissimilar material joining method of this embodiment, since the aluminum-based coating layer 4 from which the oxide film has been removed by the cleaning action is melted by arc heat, the molten metal formed by the aluminum-based coating layer 4 Is sufficiently wet and spreads on the surface of the steel material 1. Moreover, in the dissimilar material welding method of this embodiment, the Al-Si type filler material is used as the welding wire 6, and the aluminum type material 2, the welding wire 6, and the aluminum type coating layer 4 are all the same kind of metals. It is made of material. For this reason, the molten metal formed by melting the end portion of the aluminum-based material 2 and the molten metal formed by melting the welding wire 6, and the molten metal of the aluminum-based coating layer 4 wetted and spread on the surface of the steel material 1 The aluminum material 2 and the steel material 1 can be satisfactorily bonded with a wide area.

Moreover, in the dissimilar material joining method of this embodiment, since the aluminum-type coating layer 4 is formed on the surface of the steel material 1, the molten metal and the welding wire 6 formed by melting the end part of the aluminum-type material 2 include The molten metal formed by melting and the steel material 1 are not directly mixed. Thereby, it is possible to prevent the formation of hard and brittle intermetallic compounds such as Fe ₂ Al ₅ and FeAl ₃ in the joint, that is, the weld metal 7. However, when the steel material 1 is melted during welding, the melt of the steel material 1 comes into contact with a molten metal made of an aluminum alloy, and an intermetallic compound that reduces the joint strength of the joint is easily generated. For this reason, in the dissimilar material joining method of this embodiment, it is preferable to weld on the conditions which the steel materials 1 do not fuse | melt.

  In the dissimilar material joining method of the present embodiment, MIG arc welding is performed using the filler material of the first embodiment described above, but the present invention is not limited to this, and the second embodiment described above. The same effect can be obtained even when the filler material of the sixth embodiment is used. The welding method is not limited to MIG arc welding, and any welding method using a filler material such as TIG welding, arc welding, laser welding, and hybrid welding using both an arc and a laser can be applied.

  Furthermore, in the dissimilar material joining method of the present embodiment, the steel material 1 having the aluminum-based coating layer 4 provided on the front and back surfaces is used. However, the present invention is not limited to this, and the aluminum-based coating layer is used. 4 should just be provided in the location required for joining, and may be formed locally. Specifically, it should just be provided in the area | region where the arc of the surface which the arc hits in the steel material 1 hits at least, and also being formed also in the part overlapped with the aluminum-type material 2 in the surface of the steel material 1. Is preferred.

  Furthermore, in the dissimilar material joining method of the present embodiment, the plate-shaped steel material 1 and the aluminum-based material 2 are used as the materials to be welded. It does not have to be plate-shaped, and the portions overlapped with each other only need to be plate-shaped, and can be applied to various shapes and castings.

Hereinafter, the effect of the Example of this invention is demonstrated compared with the comparative example which remove | deviates from the scope of the present invention. First, as a first embodiment of the present invention, an Al—Si based filler material or an Al—Mg based filler material having the composition shown in Table 1 below is used, and the thickness is determined by the method shown in FIGS. An aluminum alloy plate made of JIS standard A5182P-O material at 1.0 mm or an aluminum alloy plate made of 6022-T4 material defined by AA (Aluminum Association) standard, and a thickness of 1.0 mm A coated steel sheet having a total weight per unit area of 50 g / m ² , 100 g / m ² or 200 g / m ² on the front and back surfaces of a general cold-rolled steel sheet SPCC, or a thickness of 2 0.0 mm of general cold-rolled steel sheet SPCC for general use and the coated steel sheet on which the aluminum plating layer with a total weight of 100 g / m ² is formed on both the front and back surfaces is overlapped by various MIG welding The joints of Examples 1 to 20 and Comparative Examples 1 to 6 were prepared by welding. The aluminum alloy plate and the coated steel plate used for each joint, and the welding method for each joint are also shown in Table 1 below.

And about the lap fillet joint of the Example and comparative example which were welded by the above-mentioned method, it processed into the test piece as described in JIS standard Z2201-5, the tensile test was done, and the tensile fracture strength was evaluated. Moreover, in order to evaluate baking characteristics, after processing the joint of the above-mentioned Example and the comparative example into a test piece described in JIS standard Z2201-5, heat treatment was performed at 200 ° C. for 30 minutes. The tensile test was conducted in the same manner and conditions. These results are summarized in Table 3 below. In addition, evaluation about the intensity | strength before baking shown in following Table 3 is (circle), the case where it is 180 N / mm or more and less than 240 N / mm when the tensile fracture strength is 240 N / mm or more, and 160 N / mm or more and 200 N / mm. The case of less than Δ is Δ, and the case of less than 160 N / mm is ×. In addition, in the evaluation of the improvement rate by baking, the case where the improvement rate was 100% or more was evaluated as ◯, the case where it was 90% or more and less than 100% was evaluated as Δ, and the case where it was less than 90% was evaluated as ×. Furthermore, comprehensive evaluation was performed based on Table 2 below. At that time, the absolute value of the elongation before baking and after baking and the change in elongation due to baking were taken into consideration, and particularly when both strength and elongation decreased, it was judged that the material was brittle and the evaluation was lowered.

  As shown in Table 3 above, the joints of Comparative Examples 1 and 2 using an Al-Si filler metal whose Si content exceeds the range of the present invention have low strength, and the joint strength is reduced by baking. did. In addition, the joints of Comparative Examples 3 and 4 had low joint strength because the Si content in the Al—Si filler metal was less than the range of the present invention. Furthermore, the joint of the comparative example 5 which uses Al-Mg type | system | group filler material with less Mg content of the filler material than the range of this invention, and the filler material whose Mg content exceeds the range of this invention. All the joints of Comparative Example 6 used had low joint strength. On the other hand, the joints of Examples 1 to 19, which were welded using a filler metal having a composition within the scope of the present invention, all had excellent strength.

Next, as a second embodiment of the present invention, a filler material in which Mg, Mn, Cr, or Zr is added to an Al—Si based filler material is used, and the thickness shown in FIG. Aluminum having a basis weight of 100 g / m ² with a total surface of both sides of an aluminum alloy plate made of JIS standard A5182P-O material and a cold-rolled steel plate for general use having a thickness of 1.0 mm. The coated steel sheet on which the plating layer was formed was overlapped and fillet welded by AC MIG welding to produce joints of Examples 20 to 27 and Comparative Examples 7 to 18. Table 4 below shows the composition of each filler material, the aluminum alloy plate and coated steel plate used for each joint, and the welding method for each joint.

  And about the lap fillet joint of the Example and comparative example which were welded by the above-mentioned method, the tensile fracture strength before and behind baking was evaluated on the same method and conditions as the above-mentioned 1st Example. The results are shown in Table 5 below.

  As shown in Table 5 above, the joint of Comparative Example 7 using the filler material having an Mg content of less than 0.1% by mass is the joint of Example 5 using the filler material to which no Mg was added. The strength was the same, and the effect of adding Mg was not obtained. Further, the strength of the joint of Comparative Example 8 using a filler material having an Mg content exceeding 0.3% by mass significantly decreased after baking. Furthermore, the strength of the joint of Comparative Example 9 using a filler metal having a Mg content within the range of the present invention but having a Si content of less than 1.5% by mass significantly decreased after baking. Furthermore, the joint of Comparative Example 10 using the filler material having the Mg content within the scope of the present invention but having the Si content exceeding 6.0% by mass had low strength before baking.

  The joint of Comparative Example 11 using a filler material having an Mn content of less than 0.1% by mass is equivalent in strength to the joint of Example 5 in which Mn is not added, and the effect of adding Mn is obtained. I couldn't. Further, the strength of the joint of Comparative Example 12 using a filler material having a Mn content exceeding 0.3% by mass was significantly reduced after baking. Furthermore, the joint of Comparative Example 8 using a filler metal having a Mn content within the range of the present invention but having a Si content of less than 1.5% by mass significantly decreased in strength after baking. Furthermore, the joint of Comparative Example 14 using the filler material having the Mn content within the range of the present invention but having the Si content exceeding 6.0% by mass had low strength before baking.

  The joint of Comparative Example 15 using the filler material having a Cr content of less than 0.05% by mass can obtain only the same strength as the joint of Example 5 to which Cr is not added, and the effect of adding Cr There was no. Further, the joint of Comparative Example 16 using the filler material having a Cr content exceeding 0.20 mass% had low strength both before baking and after baking. The joint of Comparative Example 17 using the filler material having a Zr content of less than 0.1% by mass can obtain only the same strength as the joint of Example 5 to which Zr is not added, and the effect of adding Zr. There was no. Further, the joint of Comparative Example 18 using the filler material having a Zr content exceeding 0.2% by mass had low strength both before and after baking.

  On the other hand, all of the joints of Examples 20 to 27 using the filler material in which Mg, Mn, Cr, or Zr was added to the Al—Si based filler material within the scope of the present invention added these elements. The strength was improved as compared with the joint of Example 5 which was welded using a filler metal that was not used.

Next, as a third embodiment of the present invention, a filler material in which Mn, Cr or Zr is added to an Al—Mg-based filler material is used, and the thickness is increased by the method shown in FIGS. An aluminum plating layer having a total weight per unit area of 100 g / m ² on both the front and back surfaces of a 1.0 mm thick aluminum alloy plate made of JIS standard A5182P-O material and a 1.0 mm thick cold rolled steel sheet for general use The coated steel sheet on which the metal plate is formed is overlapped and welded by AC MIG welding to produce joints of Examples 28 to 33 and Comparative Examples 19 to 26. Table 6 below shows the composition of each filler material, the aluminum alloy plate and the coated steel plate used for each joint, and the welding method for each joint.

  And about the lap fillet joint of the Example and comparative example which were welded by the above-mentioned method, the tensile fracture strength before and behind baking was evaluated on the same method and conditions as the above-mentioned 1st Example. The results are shown in Table 7 below.

  As shown in Table 7 above, the strength of the joint of Comparative Example 19 using a filler material having a Mn content of less than 0.1% by mass uses an Al—Mg-based filler material to which Mn is not added. The effect of adding Mn was not obtained. Further, the strength of the joint of Comparative Example 20 using a filler metal having a Mn content exceeding 0.3% by mass was significantly reduced after baking. Furthermore, the joint of Comparative Example 21 using a filler metal whose Mn content is within the scope of the present invention but whose Mg content is less than 2.0% by mass has low strength before baking, and further strength after baking. Decreased. Furthermore, the joint of Comparative Example 22 using a filler metal whose Mn content is within the scope of the present invention but whose Mg content exceeds 3.5% by mass is any strength before baking and after baking. Was also low.

  The joint of Comparative Example 23 using the filler material having a Cr content of less than 0.05% by mass can obtain only the same strength as the joint using the Al—Mg based filler material to which no Cr is added. There was no effect of adding Cr. Further, the joint of Comparative Example 24 using a filler material having a Cr content exceeding 0.20% by mass decreased in strength after baking. The joint of Comparative Example 25 using the filler material having a Zr content of less than 0.1% by mass can obtain only the same strength as the joint using the Al—Mg based filler material not containing Zr. There was no effect of adding Zr. Further, the joint of Comparative Example 26 using the filler material having a Zr content exceeding 0.2% by mass had low strength both before baking and after baking.

  On the other hand, the joints of Examples 28 to 33 using the filler material in which Mn, Cr or Zr was added to the Al—Mg-based filler material within the scope of the present invention were compared with the joints of the comparative examples 19 to 26 described above. Also, the strength was excellent, and the strength was improved as compared with the joint using the filler material to which these elements were not added.

Next, as a fourth embodiment of the present invention, a filler material in which Mn, Cr or Zr is added to an Al—Si—Mg based filler material is used, and the thickness is increased by the method shown in FIGS. The basis weight of 100 g / m ² is the total weight of both sides of the aluminum alloy plate made of JIS standard A5182P-O material and the general cold-rolled steel plate SPCC having a thickness of 1.0 mm. The coated steel sheet on which the aluminum plating layer was formed was overlapped and welded by AC MIG welding to produce joints of Examples 34 to 39 and Comparative Examples 27 to 36. Table 8 below shows the composition of each filler material, the aluminum alloy plate and coated steel plate used for each joint, and the welding method for each joint.

  And about the lap fillet joint of the Example and comparative example which were welded by the above-mentioned method, the tensile fracture strength before and behind baking was evaluated on the same method and conditions as the above-mentioned 1st Example. The results are shown in Table 9 below.

  As shown in Table 9 above, the joint of Comparative Example 27 using a filler material having a Mn content of less than 0.1% by mass, and a filler material having a Mn content exceeding 0.3% by mass. The joint of Comparative Example 28 used was equivalent in strength to a joint using an Al—Si—Mg based filler material to which Mn was not added, and the effect of adding Mn was not obtained. In addition, the joint of Comparative Example 29 using a filler metal whose Mn content and Mg content are within the scope of the present invention but whose Si content is less than 1.5 mass% is the strength before baking and after baking. The joint of Comparative Example 30 having a low Si content and a Si content exceeding 6.0% by mass significantly decreased in strength after baking. Further, the joint of Comparative Example 31 using the filler material having the Mn content and the Si content within the scope of the present invention but the Mg content being less than 0.1% by mass is an Al—Si based filler material. The joint of Comparative Example 32 using a filler material having a Mg content exceeding 0.3% by mass is obtained only before and after baking. The strength slightly decreased.

  The joint of Comparative Example 33 using the filler material having a Cr content of less than 0.05% by mass obtained only the same strength as the joint using the Al—Si—Mg based filler material to which no Cr was added. No effect was obtained by adding Cr. Moreover, the joint of the comparative example 34 using the filler material in which Cr content exceeds 0.20 mass% had low strength both before baking and after baking. The joint of Comparative Example 35 using the filler material having a Zr content of less than 0.1% by mass obtained only the same strength as the joint using the Al—Si—Mg based filler material not containing Zr. There was no effect of adding Zr. Further, the joint of Comparative Example 36 using the filler material having a Zr content exceeding 0.2% by mass had low strength both before baking and after baking.

  On the other hand, the joints of Examples 34 to 39 using a filler material in which Mn, Cr or Zr is added to the Al—Mg-based filler material within the scope of the present invention are more suitable than the joints of Comparative Examples 27 to 36 described above. Also, the strength was excellent, and the strength was improved as compared with the joint using the filler material to which these elements were not added.

  INDUSTRIAL APPLICABILITY The present invention is suitable for manufacturing composite structural materials used for various structural materials of automobiles by welding aluminum-based materials and iron-based materials.

It is a perspective view which shows the different material joining method. It is sectional drawing which shows the junction part of the joint joined by different materials.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Steel material 2; Aluminum-type material 3; Overlapping part 4; Aluminium-type coating layer 5; Torch 6; Welding wire 7; Weld metal

Claims (8)

In a filler material used for joining different materials for welding aluminum or an aluminum alloy material and a steel material provided with an aluminum-based coating layer made of aluminum or an aluminum alloy on its surface, Si: 1.5 to 6.0% by mass A filler material for joining dissimilar materials, wherein the balance is made of Al and inevitable impurities. Furthermore, Mg: 0.1 thru | or 0.3 mass% is contained, The filler material for different material joining of Claim 1 characterized by the above-mentioned. In a filler material used for joining different materials for welding aluminum or an aluminum alloy material and a steel material having an aluminum-based coating layer made of aluminum or an aluminum alloy on its surface, Mg: 2.0 to 3.5% by mass A filler material for joining dissimilar materials, wherein the balance is made of Al and inevitable impurities. Further, it contains one element selected from the group consisting of Mn: 0.1 to 0.3% by mass, Cr: 0.05 to 0.20% by mass, and Zr: 0.1 to 0.2% by mass. The filler material for dissimilar material joining according to any one of claims 1 to 3, wherein: Si: containing 1.5 to 6.0% by mass, the balance is made of a filler material made of Al and inevitable impurities, and an aluminum or aluminum alloy material and an aluminum-based coating layer made of aluminum or an aluminum alloy on the surface A dissimilar material joining method characterized by welding a provided steel material. The dissimilar material joining method according to claim 5, wherein the filler material further contains Mg: 0.1 to 0.3 mass%. Mg: containing 2.0 to 3.5% by mass, the balance is made of Al and an inevitable impurity filler metal, aluminum or aluminum alloy material, and aluminum-based coating layer made of aluminum or aluminum alloy on the surface A dissimilar material joining method characterized by welding a provided steel material. The filler material is further selected from the group consisting of Mn: 0.1 to 0.3% by mass, Cr: 0.05 to 0.20% by mass, and Zr: 0.1 to 0.2% by mass. The dissimilar material joining method according to any one of claims 5 to 7, comprising one kind of element.

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