JP3772731B2 - Lap joint structure using aluminum base metal and its welding method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a structure of a lap joint using an aluminum base material and a welding method thereof, and particularly to a structure of a lap joint formed by welding an aluminum base material by a MIG welding method and a welding method thereof.
[0002]
[Prior art and problems to be solved by the invention]
As shown in FIG. 3, for example, a so-called channel-shaped material 11, 12 having a U-shaped cross section is formed using a steel plate or the like, and then MIG welding is performed so that the two channel-shaped materials 11, 12 are welded joints. The structural members 10 having a rectangular closed cross-section structure are welded and joined to each other by fillet welding according to the method. A welded portion by fillet welding is denoted by reference numeral 13. In this case, if the dimension accuracy at the time of press forming is controlled in advance so that the gap dimension C is about 0 to 1.0 mm in consideration of the variation of the gap dimension C between the mating surfaces in the welded portion 13. Good welding is possible, and the welding strength as a structural member is not particularly problematic. Note that the structural member 10 having the above-described closed cross-sectional structure is used as a skeleton member of a car body of an automobile, for example.
[0003]
On the other hand, when the aluminum plate is used as a base material to form a structural member having a rectangular closed cross-sectional structure in the same form as in FIG. When managed so as to be about 1.0 mm, blowholes are prominent during welding particularly in the region where the gap dimension C is 0.5 mm or less, and the welding strength tends to be significantly reduced. This is presumed to be based on the fact that the gap C formed by the mating surfaces in the welded portion 13 is too small, and the penetration or welding in the gap formed by the mating surfaces becomes insufficient.
[0004]
Therefore, in order to maintain the welding strength as a structural member while suppressing the occurrence of blowholes on the premise that a channel-shaped material having an aluminum plate as a base material is used, the gap dimension C between the above-mentioned welded surfaces is set. However, when each channel-shaped material is formed by a normal press method, the gap dimension C including the above-described variation is 0.5 mm or more and 1.0 mm. It was impossible to maintain below.
[0005]
The present invention has been made paying attention to such a conventional problem, and when a welded joint is made by using an aluminum plate as a base material, a variation in gap dimension between mating surfaces to be welded portions is allowed to some extent. However, an object of the present invention is to provide a joint structure capable of improving and stabilizing the welding strength by suppressing the occurrence of blowholes and a welding method thereof.
[0006]
[Means for Solving the Problems]
The invention according to claim 1 is a structure of a lap joint in which a part of an aluminum base material is overlapped and then fillet welded by a MIG welding method, and any one of them is overlapped with each other. A concave groove that opens toward the region that should become a fillet is intermittently formed in advance along the welding direction on the mating surface.
[0007]
Further, the invention described in claim 2 is obtained from the manufacturing aspect of the invention described in claim 1 above, and a part of the aluminum base material is overlapped, and then the MIG welding method is used. When forming a lap joint by performing meat welding, a concave groove that opens toward the region that should become fillet is intermittently formed in advance along the welding direction on one of the mating surfaces to be overlapped with each other. In addition, fillet welding is performed so as to conceal the opening of the concave groove.
[0008]
Therefore, in the inventions according to claims 1 and 2, even if the gap dimension formed by the mating surfaces of the aluminum base materials varies, the grooves are intermittently formed in advance along the welding direction. Regardless of the size of the gap formed by the mating surfaces, at least a gap corresponding to the depth of the groove is intermittently secured in the welding direction. Therefore, while allowing variation in the gap size between the welded surfaces, the occurrence of blowholes when fillet welding is performed as continuous welding by MIG welding is suppressed, and the melting or welding of the mating surfaces is ensured. The necessary and sufficient welding strength can be secured.
[0009]
【The invention's effect】
According to the first and second aspects of the invention, when the aluminum base material is subjected to MIG welding to form a lap joint, a concave groove is intermittently formed in advance along the welding direction on one of the mating surfaces. Therefore, even if the gap dimension formed by the mating surfaces is not strictly managed, there is an effect that it is possible to ensure the necessary and sufficient welding strength by allowing the variation of the gap dimension and suppressing the occurrence of blowholes.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 are views showing a preferred embodiment of the present invention. In particular, FIG. 1A is a U-shaped cross-section that constitutes a structural member 10 having a closed cross-sectional structure similar to that shown in FIG. 1B is a perspective view of one of the channel-shaped materials, FIG. 2B is an enlarged view of a part in FIG. 1A, and FIG. 2 is a plan view of the main part in FIG. ing.
[0011]
As shown in FIGS. 1 and 2, one channel-shaped material 1 having an aluminum plate as a base material is formed in advance in a U-shaped cross-section together with the other channel-shaped material 2. For the material 1, a large number of concave grooves 3, 3... Are formed in advance along the longitudinal direction on the inner side surfaces of the flange portions 1b, 1b formed upright on both sides of the web 1a.
[0012]
More specifically, on the inner surface of the front end of each flange portion 1b, 1b of the channel-shaped material 1 and the portion overlapped with the flange portions 2b, 2b of the other channel-shaped material 2 on the other side, Concave grooves 3 that gradually decrease in groove depth d are formed intermittently or intermittently at equal pitches along the longitudinal direction (welding direction) of the flange portions 1b and 1b. The plurality of concave grooves 3, 3... Are formed, for example, by printing with a press at the stage of the flat plate before the channel-shaped material 1 or at the stage of being pressed into a channel shape. Therefore, the front inner surface of each flange portion 1b, 1b of the channel-shaped material 1 is formed as an irregular mating surface 4 having regularity as shown in FIG.
[0013]
Therefore, according to the present embodiment, the inner surface of the flange portion 1b of one of the channel-shaped materials 1 is arranged so that the openings of the two channel-shaped materials 1 and 2 face each other in the same manner as shown in FIG. And the outer surface of the flange portion 2b of the other channel-shaped material 2 are positioned relative to each other, and in the form of fillet welding, each groove is formed along the front end surface 1c of the flange portions 1b and 1b. Continuous welding by MIG welding is performed so as to conceal the openings of 3, 3.
[0014]
In addition, the clearance dimension C (refer FIG. 1) in the mating surface 4 which should become a welding part of both channel-shaped raw materials 1 and 2 is a thing within the range of 0-1.0 mm including dispersion | variation similarly to the past. It is managed to become.
[0015]
In this case, since the numerous concave grooves 3, 3... Formed on the inner side surfaces of the flange portions 1b, 1b are previously opened in a region that should be filled with weld overlay, As described above, even if the gap C between the mating surfaces of the two channel-shaped materials 1 and 2 varies, the gap between the mating surfaces 4 and 4 is not affected by the degree of variation. A gap corresponding to the depth d of at least the concave grooves 3, 3... Is surely secured. That is, even if the gap dimension C formed between the mating surfaces 4 and 4 of the two channel-shaped materials 1... 2 varies and partially becomes zero, the concave groove 3 adjacent to the portion may be zero. In the portion 3..., At least a gap corresponding to the groove depth d of the concave grooves 3, 3.
[0016]
As a result, when continuous welding by MIG welding is performed as described above, the gap corresponding to the depth d of the concave grooves 3, 3... Is intermittently formed along the direction in the welding direction. Regardless of the size of the gap dimension C, the welding or welding between the mating surfaces 4 and 4 is reliably performed, and the welding strength becomes necessary and sufficient.
[0017]
Here, in the present embodiment, the concave grooves 3, 3... Are formed on the inner surface of the flange portion 1b in one channel-shaped material 1, but instead of this, the outside of the flange portion 2b in the other channel-shaped material 2 is formed. The same effect can be obtained by forming the concave grooves 3, 3. Moreover, although the example in the case of forming the structural member 10 of a closed cross-sectional shape by butting together the channel-shaped raw materials 1 and 2 and performing MIG welding in the previous example was shown, other than the form of a lap joint, It goes without saying that the present invention can also be applied to welded joints.
[Brief description of the drawings]
FIG. 1 is a view showing a preferred embodiment of the present invention, in which (A) is a perspective view of a channel-shaped material formed by bending an aluminum plate into a U-shaped cross section, and (B) is shown in FIG. The a section enlarged view at the time of setting it as a lap joint using a channel-shaped raw material.
FIG. 2 is an enlarged plan view of a main part in FIG.
3A is a perspective view showing a structural member having a rectangular closed cross section as an example of a lap joint using a channel-shaped material, and FIG. 3B is an enlarged view of a portion b in FIG. 3A.
[Explanation of symbols]
1 ... Channel material (aluminum base material)
1b ... Flange 3 ... Groove 2 ... Channel material (aluminum base material)
4 ... mating surface 10 ... structural member

Claims (2)

A structure of a lap joint in which a part of an aluminum base material is overlapped and fillet welded by MIG welding method,
An aluminum base material characterized in that, on either one of the mating surfaces to be overlapped with each other, a concave groove that opens toward the region to be filled is intermittently formed in advance along the welding direction. The lap joint structure used. In making a lap joint by performing fillet welding by MIG welding method after overlapping a part of aluminum base material,
On either one of the mating surfaces that are to be overlapped with each other, a concave groove that opens toward the region that should become fillet is intermittently formed in advance along the welding direction,
A welding method for a lap joint using an aluminum base material, wherein fillet welding is performed so as to conceal the opening of the concave groove.

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