JPH10113783A - Laser beam welding method for plated steel plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure a satisfactory weld quality by irradiating with a laser beam while forming easily and stably a specific gap between both plates in the welding method welding the lap joint of a pair of the plated steel plates by a laser beam. SOLUTION: Surfaces on the one side of first and second plated plates 10, 20 are locally and successively pressured almost vertically by the steel sphere 41 of a local pressing device 40. And, the surfaces on the one side of the first and the second plated plates 10, 20 are successively irradiated almost vertically by the laser beam from a laser beam machine 30 in a position removed by a proscribed distance from this pressure part Thus, the lap joint of the first and the second plated plates 10 and 20 is welded with a satisfactory weld quality.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding method for welding a set of base materials by a laser beam, and more particularly, to a laser welding method for overlapping a set of plated steel sheets and performing lap joint welding.

[0002]

2. Description of the Related Art As a method of welding a plurality of base materials, a laser welding method of irradiating a laser beam with a laser beam in recent years has been adopted. When a plated steel sheet is used as the base material and a set of coated steel sheets is overlapped and laser-welded, there is a problem that the molten pool surface becomes rough and rough due to the presence of the plating layer at the contact portion between the two steel sheets. Was.

In order to address this problem and perform welding while maintaining a good molten pool surface shape without requiring a high-precision jig, the present applicant has disclosed in Japanese Patent Application Laid-Open No. 7-155974. As described above, at least a projection is formed on the first plated steel sheet, and the top of the projection is brought into contact with the surface of the second plated steel sheet, and the top of the projection is opposed to the first plated steel sheet from the side opposite to the top of the projection. A laser welding method for irradiating a laser beam and welding first and second plated steel sheets has been proposed.

[0004]

To solve the above problem, a shim plate is interposed between the first plated steel sheet and the second plated steel sheet so as to clamp the gap between the two steel sheets. (Voids) can be formed. Therefore, according to this method, the same effect as the method of forming and projecting the protrusions described in the above publication can be expected.

However, in any of the above methods,
Prior to the welding step, it is necessary to form a projection on the first plated steel sheet or to interpose a shim plate between the first plated steel sheet and the second plated steel sheet in advance, which is an extra step. Becomes Moreover, it is difficult to dispose and fix the shim plate by the method of clamping with the shim plate interposed therebetween, and there is a problem that the gap is not stable depending on the clamping method.

Accordingly, the present invention provides a welding method for welding a set of plated steel sheets by lap joint using a laser beam, by irradiating a laser beam while easily and stably forming a constant gap between the two steel sheets. It is an object to provide a laser welding method capable of securing welding quality.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a plating method comprising: laminating a set of base materials composed of first and second plated steel sheets and performing lap joint welding with a laser beam. In the laser welding method for a steel sheet, the first and second plated steel sheets are overlapped and locally and sequentially pressed substantially perpendicularly to one surface of the first and second plated steel sheets. The first and second plated steel sheets are welded by sequentially irradiating a laser beam substantially perpendicularly to the one surface at a position separated from the first steel sheet by a predetermined distance.

[0008] According to a second aspect of the present invention, the first type is provided.
And locally pressurizing sequentially from a direction inclined at a first predetermined angle with respect to an axis perpendicular to one surface of the second plated steel sheet, and the one surface is positioned at a predetermined distance from the pressing portion. It is preferable to sequentially irradiate a laser beam from a direction inclined by a second predetermined angle with respect to an axis perpendicular to the laser beam, so that the irradiation direction of the laser beam and the pressing direction form a third predetermined angle.

Alternatively, as described in claim 3, a pressing means for locally pressing substantially perpendicularly to one surface of the first and second plated steel sheets, and a predetermined pressing means for the pressing means. Laser beam irradiating means for irradiating a laser beam on the one surface substantially perpendicular to the one surface, the first and second plated steel sheets, the pressing means and the laser beam irradiating means, You may make it translate relatively.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first and second plated steel sheets 1 by a laser welding method according to an embodiment of the present invention.
The situation of laser welding a set of base materials consisting of 0, 20 is shown. In the present embodiment, the first and second plated steel sheets 10, which are formed in substantially the same container shape having a flange portion on the periphery,
20 are overlapped and lap joint welding is performed on the flange to form a fuel tank (indicated by FT in FIG. 4). First and second plated steel sheets 1 of the present embodiment
As shown in the enlarged view of FIG. 3, reference numerals 0 and 20 denote plating layers 12, 13 and 22, 2 on both surfaces of the steel plates 11 and 21, respectively.
3 is formed.

FIG. 4 shows an entire apparatus for performing the laser welding method according to the present embodiment. A support 2 is fixed on a base 1a, and a support beam 1c is set substantially horizontally via a support leg 1b. It is laid down. Moving devices 3 and 4 are horizontally movably supported by the support beam 1c, and a laser device 30 and a local pressurizing device 40 are fixed to each of them. On the other hand, a support 2a is fixed on the support 2, and the first and second plated steel sheets 10,
Each of the flange portions 20 is supported substantially horizontally in a superposed state. That is, the first supported at a predetermined position on the support base 2
The moving devices 3 and 4 movably supported by the support beam 1c move parallel to the second plated steel plates 10 and 20 along the flange portion while maintaining a predetermined positional relationship with each other. Is configured.

The local pressurizing device 40 has a steel ball 4
1 (for example, a diameter of 10 to 15 mm) is rotatably supported, and the steel ball 41 is pressed toward the member to be welded by the pressing cylinder 42. On the other hand, although the overall configuration of the laser device 30 is omitted, as shown in FIG. 3, a laser beam LA output from a laser generator (not shown) is supplied to a lens 32 held by a lens holder 31. And irradiates the first and second plated steel sheets 10 and 20 as minute spots with high energy density.

The laser device 30 and the local pressurizing device 40
Are held in a predetermined positional relationship shown in FIG. That is, the local pressurizing device 40 is configured to use the first and second plated steel sheets 1.
It is arranged to apply pressure locally in a direction inclined by a first predetermined angle (α) with respect to an axis perpendicular to one of the surfaces 0, 20. Then, the laser device 30 emits a laser beam in a direction inclined by a second predetermined angle (β) with respect to an axis perpendicular to the one surface at a position separated by a predetermined distance (D) from the pressurizing section. Is arranged. As a result, the irradiation direction of the laser beam and the pressing direction are the third predetermined angle (γ).
The laser device 30 and the local pressurizing device 40 are respectively fixed to the moving devices 3 and 4 in FIG. The first predetermined angle (α), the second predetermined angle (β), and the predetermined distance (D) are set according to the thickness of the first and second plated steel sheets 10 and 20, and the like.

The local pressurizing device 40 and the laser device 30 arranged as described above move synchronously on one of the flange portions of the first and second plated steel plates 10 and 20. When the first and second plated steel plates 10 and 20 are sequentially pressed by the steel balls 41 in the direction of the arrow indicated by P in FIG.
As the reaction, the first and second plated steel sheets 10, 20
As shown in FIG. 2, a minute gap h is formed between both steel plates. This gap h is formed sequentially with the movement of the steel ball 41, but the first and second plated steel sheets 10,
A constant value (for example, 10 to 100 μm) over the entire circumference of a 20 (for example, 0.8 to 1.2 mm thick) flange portion
Becomes

Subsequently, a predetermined distance (D) from the pressing portion of the local pressing device 40 against the first and second plated steel plates 10 and 20 by the steel balls 41 is applied from the laser device 30 to FIG.
When the laser beam LA is sequentially irradiated as shown by a broken line, the first and second plated steel sheets 10 and 20 are seam-welded. That is, first, the first plated steel sheet 10 and then the second
Of the coated steel sheet 10 is melted to form a molten pool (not shown). At this time, the plating layers 12, 13, 2
2 and 23 are also melted and metal vapor is generated, but the metal vapor generated at the joint between the first and second plated steel sheets 10 and 20 is released to the atmosphere through the gap h, so that bubbles are generated in the molten pool. Does not remain, and the surface of the first plated steel sheet 10 becomes a smooth surface.

As described above, according to the laser welding method of the present embodiment, the trajectory where the gap h is sequentially formed coincides with the trajectory to be irradiated with the laser beam, and the metal vapor is discharged to the atmosphere via the gap h. Since no bubbles remain in the molten pool, lap joint welding can be performed while maintaining a good surface shape, and good fastening strength can be obtained. In particular, since the gap h sequentially formed between the first and second steel plates 10 and 20 is substantially constant, there is no variation between products, and stable welding quality (fastening strength, airtightness, etc.) is ensured. Can be.

Further, the gap h is the steel ball 4 of the local pressurizing device 40.
Since it is formed in accordance with the pressurizing operation by No. 1, there is no need for a protrusion or a shim plate for maintaining the gap h. In addition, since the member to be welded is sequentially pressed by the local pressurizing device 40 prior to welding, the conventional method does not require the entire circumference clamp required for holding the member to be welded. Therefore,
The unit cost of the product can be further reduced as compared with the conventional method, and generalization is easy.

FIG. 5 relates to another embodiment of the laser welding method of the present invention, in which a laser device 30 and a local pressurizing device 40 are fixed to a support leg 5 and a support 2 a is attached to the tip of an arm 101 of a robot device 100. Fuel tank F to be welded
T (the first and second steel plates 10 and 20 are superposed) is configured to move in parallel. Thus, since the laser device 30 and the local pressurizing device 40 relatively move in parallel along the flange portion of the fuel tank FT, the same effects as in the above-described embodiment can be obtained.

[0019]

Since the present invention is configured as described above, the following effects can be obtained. That is, according to the laser welding method for a plated steel sheet of the present invention, the first and the second plated steel sheets are overlapped and locally and sequentially pressed substantially perpendicularly to one of these surfaces, and from the pressed portion. The first and second plated steel sheets are welded by sequentially irradiating a laser beam substantially perpendicularly to one surface at a position separated by a predetermined distance, so that a certain distance is provided between the first and second plated steel sheets. The laser beam can be sequentially emitted while easily and stably forming the air gap, so that good welding quality can be ensured and lap joint welding can be reliably performed. Particularly, by setting the pressing direction and the irradiating direction according to the second aspect according to the first and second plated steel sheets as the members to be welded, optimum welding quality can be secured.

Further, as set forth in claim 3, a pressing means for locally pressing substantially perpendicularly to one surface of the first and second plated steel sheets, and a predetermined pressing means for the pressing means. A laser beam irradiating means for irradiating a laser beam substantially perpendicularly to the one surface, and relatively moving the first and second plated steel sheets, the pressing means and the laser beam irradiating means in parallel with each other In other words, the welding can be performed as described above by driving either one side, so that various types of apparatuses can be configured as necessary.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional front view showing a situation where first and second plated steel sheets are welded by a laser welding method according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state where first and second plated steel sheets are welded by a laser welding method according to an embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view illustrating a state where first and second plated steel sheets are welded by a laser welding method according to an embodiment of the present invention.

FIG. 4 is a front view showing an apparatus for welding first and second plated steel sheets by a laser welding method according to one embodiment of the present invention.

FIG. 5 is a front view showing an apparatus for welding first and second plated steel sheets by a laser welding method according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 1st plating steel plate 11 Steel plate 12, 13 plating layer 20 2nd plating steel plate 21 Steel plate 22, 23 plating layer 30 Laser device 40 Local pressurization device

Claims (3)

[Claims] 1. A laser welding method for a plated steel sheet, comprising laminating a set of base materials made of first and second plated steel sheets and performing lap joint welding with a laser beam. Are superimposed and locally sequentially pressed substantially perpendicularly to one surface of the first and second plated steel sheets, and substantially perpendicularly to the one surface at a predetermined distance from the pressed portion. A laser welding method for a plated steel sheet, comprising sequentially irradiating a laser beam to weld the first and second plated steel sheets. 2. A local pressure is sequentially applied from a direction inclined at a first predetermined angle with respect to an axis perpendicular to one surface of the first and second plated steel sheets, and a predetermined distance from the pressing unit. Laser beams are sequentially irradiated at a distance from a direction inclined at a second predetermined angle with respect to an axis perpendicular to the one surface, and the irradiation direction of the laser beam and the pressing direction are changed to a third direction.
2. The apparatus according to claim 1, wherein the predetermined angle is formed.
The laser welding method for the coated steel sheet described in the above. 3. A pressing means for locally pressing substantially perpendicularly to one surface of the first and second plated steel sheets, and the one surface disposed at a predetermined position with respect to the pressing means. A laser beam irradiating means for irradiating a laser beam substantially perpendicular to the first and second plated steel sheets, and the pressing means and the laser beam irradiating means are relatively moved in parallel. The method for laser welding a plated steel sheet according to claim 1, wherein: