JPH0755385B2 - Method for manufacturing aluminum alloy welded can body - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of manufacturing a welded can body used for an aluminum alloy three-piece can, and particularly, to manufacture a welded can body at high speed while applying ultrasonic seam welding. It is about how to do it.

2. Description of the Related Art In manufacturing a three-piece can made of aluminum alloy, an aluminum alloy thin plate, which is a material for a can body, is curved and formed into a cylindrical shape, its ends are overlapped, and the overlapped portion is welded to form a welded can body. Further, it is usual that flanges are applied to both ends of the body of the welding can and then the lid is attached by caulking and joining. An ultrasonic seam welding method has been conventionally known as one of the welding methods for producing such a welding can body for a three-piece can. However, in the conventional ultrasonic seam welding method for aluminum alloy thin plates, the welding speed is only about 1 m / min at a plate thickness of 0.2 mm, for example,
Compared with other seam welding methods such as resistance seam welding for can body manufacturing using thin steel plates, the welding speed is significantly lower,
Therefore, since the welding work efficiency is remarkably low, there is a problem that the can manufacturing efficiency must be remarkably lowered when the ultrasonic seam welding method is applied to manufacture the aluminum alloy three-piece can.

Therefore, the present inventors have already disclosed in JP-A-62-270290,
As a method of increasing the welding speed when manufacturing the aluminum alloy welded can body by applying the ultrasonic seam welding method,
A method of forming a mash seam joint by keeping the overlap margin between the ends of the aluminum alloy sheets during ultrasonic seam welding within an appropriate range and increasing the deformation during ultrasonic welding of the overlap Is proposed.
That is, the method proposed above, the overlap margin of the end portions of the aluminum alloy sheet during ultrasonic seam welding is 0.5 to 4 mm.
It is a method of ultrasonic seam welding so that the deformation degree of the thickness is 20 to 50% while crushing the entire overlapping part within the range of, and by doing so, the seam welding speed is It has become possible to raise it to a level of 10 to 15 m / min, which is much higher than the above.

Problems to be Solved by the Invention According to the method proposed above, in the case of applying a conventional ultrasonic seam welding method to manufacture an aluminum alloy can body by applying ultrasonic seam welding, It is now possible to significantly increase the welding speed. However, in view of recent severe market competition, the method proposed above is not always sufficient, and it is strongly desired to develop a method capable of further increasing the welding speed to further improve the efficiency of can body manufacturing. .

By the way, recently, a laser welding method has been developed as a high-speed welding method, and it is considered that this laser welding method is applied to the production of an aluminum alloy can body. That is, it is conceivable that the aluminum alloy thin plate, which is the material for the can body, is curved and formed into a cylindrical shape, the ends thereof are overlapped, and the gap between the wedge-shaped interfaces of the overlapped portions is irradiated with a laser beam from the open side to perform seam welding. To be However, in the case of an aluminum alloy, since a strong oxide film is present on the surface, there is a problem that the weldability by a laser beam is poor and a welded portion having sufficient joint strength cannot be obtained. That is, even when the laser beam is irradiated under the condition of melting the aluminum alloy thin plate surface layer at the wedge-shaped interface of the overlapping portion, the oxide film on the surface remains in a block state in an unmelted state, and the unmelted block-shaped oxide film melts. There is a possibility that welding will be impeded by the hindrance of joining and sufficient joint strength may not be obtained. In addition, solidification cracking easily occurs in the case of aluminum alloys because resolidification after melting with a laser beam is rapid cooling. On the other hand, in order to avoid this problem, the energy of the laser beam is controlled to a small value and the aluminum alloy sheet surface layer Under conditions that do not melt,
It is possible to perform high temperature solid pressure welding, but in this case as well, the presence of an oxide film on the surface of the aluminum alloy inevitably deteriorates the pressure welding property. However, in this case, the plate thickness of the joint is extremely thin, and sufficient joint strength cannot be obtained. Therefore, for these reasons, it was considered impractical to apply laser welding to the manufacture of aluminum alloy can bodies.

The present invention has been made in view of the above circumstances, and in manufacturing an aluminum alloy welded can body by applying ultrasonic seam welding as described above, even if the welding speed is remarkably faster than the conventional joint, It is an object of the present invention to provide a method capable of obtaining a welded portion having excellent performance so that the manufacturing efficiency of a can body can be greatly improved as compared with the conventional method.

Means for Solving the Problems In the present invention, the above-mentioned problem is basically solved by using a laser welding method together with ultrasonic seam welding and utilizing the synergistic effect of both.

Specifically, the method for producing a body of an aluminum alloy welded can of the present invention is a method of bending a material aluminum alloy thin plate into a cylindrical shape so that both ends are overlapped with each other, and a laser beam is applied from a release side to a gap in a wedge-shaped interface of the overlapping part. It is characterized in that the overlapping portion is ultrasonically seam welded while irradiating the beam.

Action In the method of the present invention, as shown in FIGS. 1 and 2, for example, the aluminum alloy thin plate 1 of the can body material is curved and formed into a cylindrical shape, and both end edges 1A and 1B thereof are overlapped. At this time, in the overlapping portion 2, both edge portions 1A and 1B of the raw material aluminum alloy thin plate 1 are not closely adhered to each other without a gap, but a gap 3 forming a wedge-shaped interface is formed. Therefore, while irradiating the laser beam 4 from the open side to the gap 3 forming the wedge-shaped interface of the overlapping portion 2 to heat the surfaces of the aluminum alloy thin plates on both sides of the gap 3, the ultrasonic seam welding machine 5 moves the overlapping portion 2 Ultrasonic seam welding is performed to form the welded portion 6.

By using laser welding together with ultrasonic seam welding in this way, the welding speed can be increased and a welded portion having excellent joint performance can be obtained. The reason is considered as follows.

That is, generally, in ultrasonic seam welding, only the bonding interface is rubbed by ultrasonic vibration, and as a result, the new interface is exposed and the temperature is raised due to the destruction of the oxide film at the interface, and at the same time, the warm pressure welding is performed by applying pressure. Done.
Therefore, it is desirable that the temperature of the interface is high in order to increase the bondability, but there is a limit to the ability of the welding machine to give ultrasonic vibrations for friction, and the temperature of the bonding interface is normal in a normal ultrasonic seam welder. Only half of the melting temperature of the raw material aluminum alloy was reached, and therefore high-speed welding unavoidably caused a decrease in pressure contact.

On the other hand, in laser welding, only the very surface layer of the bonding interface is heated by laser beam irradiation, and the surface layer is melted or heated to a temperature close to the melting temperature and pressure is applied. Poor bondability due to lack of ability to remove unique strong oxide film.

On the other hand, according to the method of the present invention, the joining interface can be heated to a high temperature by the irradiation of the laser beam, and the strong oxide film at the joining interface can be destroyed and removed by the friction caused by the ultrasonic vibration. It is possible to obtain a welded portion with excellent joint performance even when the weld strength is significantly increased. In other words, in the case of the method of the present invention, the advantages and disadvantages of the ultrasonic seam welding method and the laser welding method are complemented to enable high-speed welding with excellent joint performance.

Here, the type of laser beam used in the method of the present invention includes a carbon dioxide gas laser and a YAG laser, but is not particularly limited.

Also, the condition of the bonding interface due to the irradiation of the laser beam is either in a molten state or an unmelted high temperature heating state,
Usually, the unmelted high temperature heating state is preferable, but it is not limited thereto. That is, in both the molten state and the unmelted high-temperature heating state, when laser welding is applied alone, a strong oxide film on the joint interface surface causes a decrease in jointability, though there is a difference in degree. By using ultrasonic seam welding together with this, the bondability can be improved in any case. The angle of the gap of the wedge-shaped interface that irradiates the laser beam in the overlapping portion is not particularly limited as long as there is a spatial margin that allows the laser beam to be incident.

In the ultrasonic seam welding according to the method of the present invention, as shown in FIG. 3, when the both end edges 1A, 1B of the aluminum alloy thin plate 1 of the can body material formed into a cylindrical shape are overlapped, The overlapping margin L is preferably within the range of 0.1 to 2.0 mm. Then, the degree of deformation of the overlapping portion 2, that is, the total thickness before welding is t ₀ , and the thickness after welding is t ₁ , the deformation represented by {(t ₀ −t ₁ ) / t ₀ } × 100 (%) Ultrasonic seam welding may be performed while crushing the entire overlapped portion 2 so that the degree is within the range of 20 to 50% to form a welded portion (lap joint portion) 6 as shown in FIG. desirable.

Here, as described above, seam welding is performed while crushing the entire overlapping portion 2 with a high degree of deformation of 20 to 50%, as shown in FIG. Not only the upper edge of the plate is crushed, but also the lower edge of the plate is almost symmetrically crushed to form a nearly flat lap joint, that is, a so-called mash seam joint. Means

Further, as the aluminum alloy used in the present invention, usually 5182 alloy, 5082 alloy, 5052 alloy, 3004 alloy,
There are 3003 alloy, 3005 alloy, 1100 alloy, 6061 alloy, etc.,
It is not particularly limited to these.

Example [Example 1] As a test material, an aluminum alloy thin plate of JIS 5182 alloy H38 with a thickness of 0.23 mm was used to form a cylindrical shape with a diameter of 50 mm and a length of 120 mm. As shown in the figure, ultrasonic seam welding is performed while irradiating the laser beam 4 from the open side to the gap 3 forming the wedge-shaped interface of the overlapping portion 2 (overlap margin 1.0 mm) of the both edge portions 1A and 1B of the aluminum alloy thin plate 1. Ultrasonic seam welding was performed by the machine 5 under the conditions shown in Table 1. As the laser beam 4, a YAG laser was used, and irradiation was performed under the conditions of an output of 600 w, continuous oscillation, and a shielding gas Ar60 / min. For ultrasonic seam welding, the welding machine output 12
00w, amplitude 19 μm, frequency 19 kHz, applied pressure 80 kg. The welding results are shown in Table 1. In Table 1, the weldability was judged to be good by giving 180 ° bending to the weld joint and preventing the weld from peeling. For comparison, the welding results were similarly examined in the case where only the ultrasonic seam welding was performed (the conditions were the same) without irradiating the laser beam, which is also shown in Table 1.

As shown in Table 1, in the example of the present invention in which ultrasonic welding was used in combination with laser beam irradiation, peeling of the welded portion did not occur at 180 ° bending even when the welding speed was increased to 100 m / min.
On the other hand, in the comparative example in which only ultrasonic welding was performed without laser irradiation, when the welding speed was 20 m / min, peeling of the weld occurred at 180 ° bending. Therefore, according to the method of the present invention, it is apparent that the welding speed can be significantly increased as compared with the case of only ultrasonic welding.

EFFECTS OF THE INVENTION As is apparent from the above-described embodiments, according to the method for manufacturing a welded can body made of aluminum alloy of the present invention, joint seam welding is performed by using laser beam irradiation in combination with ultrasonic seam welding when welding the can body. It is possible to obtain a superior welded part at a welding speed that is significantly faster than before.
Therefore, the manufacturing efficiency of the body of the welding can can be remarkably improved as compared with the conventional case.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an example of a situation in which the method of the present invention is carried out, FIG. 2 is a cross-sectional view at the laser beam irradiation position in FIG. 1, and FIG. 3 is just before ultrasonic seam welding. FIG. 4 is a schematic cross-sectional view showing the condition of the overlapping portion, and FIG. 4 is a schematic cross-sectional view showing the condition of the welded portion after ultrasonic seam welding. 1 ... Aluminum alloy thin plate, 2 ... Overlapping part, 3 ...
… Gap, 4 …… Laser beam, 5 …… Ultrasonic seam welder, 6 …… Welding area.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-62-270290 (JP, A) JP-A-57-146492 (JP, A)

Claims (1)

[Claims] 1. A material aluminum alloy thin plate is bent into a cylindrical shape so that both ends thereof are overlapped with each other, and the overlapped portion is ultrasonically seam-welded while irradiating a laser beam from the open side into a gap between wedge-shaped interfaces of the overlapped portion. A method for manufacturing a body of an aluminum alloy welded can, which is characterized by the above.