TWI696512B - Butt joint laser welding method of plate and laser welding parts - Google Patents

Abstract

A laser welding method of a steel plate, which does not use a filler and causes the laser (2) to irradiate the butt portion (4) of the butt jointing two plates (1) in a spiral or serpentine shape, and in the laser welding method, the plates The thickness is 1~6mm; the laser trajectory is drawn in a specific cycle so that the welding part of the two plates butted and welded periodically changes along the welding direction; the specific cycle is performed by performing a tensile test It is set so that the welded part is not broken but the base material is broken; the laser output system is 2~7kW, and the welding speed is 0.5~3m/min; and the butt interval G is greater than 0 and less than 2.0mm, and is relative to the welding line. The laser amplitude W is within the range of the following formula (1), G/2≦W≦G/2+2.0... (1)

Among them, W: laser amplitude (mm)

G: docking interval (mm).

Description

Butt joint laser welding method of plate and laser welding parts

The invention relates to a butt laser welding method and a laser welding component of a plate with excellent welding strength.

Due to the high energy density heat source of the laser system, it is used in various fields. Especially in welding, it is high-speed and low heat input welding, so it has the characteristics of less thermal deformation and thermal deterioration, and is used for the assembly of industrial machines or structural bodies such as automobile parts.

Among laser welding methods, welding joints such as lap fillet weld joints, T-shaped joints, butt joints, etc. are used in the same manner as other arc welding methods. In the case of the laser welding method in which the laser is irradiated from the vertical direction of the welding surface, the aiming position and the docking interval must be strictly controlled. Although the laser beam diameter varies depending on the laser oscillation method, lens, etc., it is generally as small as 0.5 mm or less. Therefore, when the aiming position is shifted, a penetration defect occurs. In addition, if a gap is formed in the butt joint portion and the butt spacing is wider than the laser beam diameter, the laser beam may pass through and welding cannot be performed.

For example, as shown in FIG. 1, if the focal position of the laser 2 is shifted to the side of the plate 1-a, the plate 1-a will be melted to form a molten portion 3, and the plate 1-b will be caused by insufficient heat input. Non-melting welding defects. In addition, when the material to be welded is cut by a cutting method such as shearing, it is difficult to cut the cut surface into a straight line and is perpendicular to the welded surface system, and also sags and deforms. Therefore, as shown in FIG. 2, the butting portion 4 becomes wider than the diameter of the laser beam 2, causing the laser 2 to pass between the plate 1-a and the plate 1-b to cause welding defects. In order to prevent this situation, mechanical grinding and trimming must be applied to the cut surface to reduce the butting interval; or fillers are used to fill the gaps, which results in increased costs.

Due to the above-mentioned problems in laser welding of the butt joints, Patent Document 1 discloses a method that uses laser-welded steel plates as a material to manufacture automotive panels, and cuts the burrs of the thin steel plates after cutting The same direction is used for butting, and the filler is supplied on the sagging side for laser welding to produce a pressed material. However, as described above, the cut end surface of the plate after shearing and cutting is not perpendicular to the welding surface, so it is difficult to perform laser welding by butting two plates precisely as in Patent Document 1. In addition, laser welding is sometimes required without fillers.

In order to solve such a butt laser welding method, Patent Documents 2 and 3 disclose a current scanning type butt laser welding method in which a current scanner irradiates a laser in a spiral or serpentine shape. As shown in FIG. 3, this method is to irradiate the two sheets 1, 1 in such a way that the helical trajectory 5 (FIG. 3a) or the serpentine trajectory 6 (FIG. 3b) of the laser 2 is drawn by the current scanner. Laser welding method of the butt joint 4.

[Prior Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Published Patent Gazette "Japanese Patent Laid-Open No. 5-84585"

[Patent Document 2] Japanese Published Patent Gazette "Japanese Patent Laid-Open No. 54-116356"

[Patent Document 3] Japanese Published Patent Gazette "Japanese Patent Laid-Open No. 8-192286"

However, even with the current-scanning butt laser welding method, if the butt spacing of the plates and the amplitude of the laser 2 are not controlled within an appropriate range, insufficient melting may occur and the molten metal may drip. This leads to a decrease in welding strength. Since the patent documents 2 and 3 only describe that the docking interval is somewhat widened, or the irradiation position of the laser beam is somewhat shifted, it still does not hinder. In fact, there are still current-scanning docking lasers of conventional technology. In the welding method, the problem of stable welding strength cannot be obtained. In view of the present situation, the present invention aims to provide a plate butt laser welding method and a laser welding component that can obtain stable and excellent welding strength.

As a result of detailed investigation by the inventors, the following insights were obtained, and the present invention was further completed. That is, in the current scanner laser welding method in which a spiral or snake-shaped trajectory is drawn with a current scanner to irradiate the butt portion 4 of the two plates 1, 1 with laser light, If the shot amplitude is controlled within an appropriate range, stable and excellent welding strength can be obtained.

That is to say, in the laser welding method of an embodiment of the present invention, the filler is not used, so that the laser irradiates the butt portion of the butt jointing the two plates in a spiral or serpentine shape, and in the laser welding method, the plate The thickness is 1~6mm; the laser trajectory is drawn in a specific cycle so that the welding part of the two plates butted and welded periodically changes along the welding direction; the specific cycle is performed by performing a tensile test It is set so that the welded part is not broken but the base material is broken; the laser output system is 2~7kW, and the welding speed is 0.5~3m/min; and the butt interval G is greater than 0 and less than 2.0mm, and is relative to the welding line. The laser amplitude W is within the range of the following formula (1), G/2≦W≦G/2+2.0 (1), where W: laser amplitude (mm)

G: docking interval (mm).

In addition, in an embodiment of the present invention, a laser welded component welded by a laser welding method, wherein the laser welding method is such that the filler is not used and the laser is irradiated in a spiral or serpentine shape to butt the two plates Butt joint, and in the laser welding method, the thickness of the plate is 1~6mm; the laser trace is drawn at a specific cycle so that the welded parts of the two plates are butted and welded periodically along the welding direction Variation; the specific period is set by conducting a tensile test so that the welded part is not broken but the base material is broken; the laser output is 2~7kW, and the welding speed is 0.5~3m/min; and the docking interval G is greater than 0 and 2.0 mm or less, and the laser amplitude W with respect to the welding line is within the range of the following formula (2), G/2≦W≦G/2+2.0 (2)

Among them, W: laser amplitude (mm)

G: docking interval (mm).

According to the present invention, it is possible to provide a butt laser welding method and a laser welding component which are stable and excellent in welding strength.

1: Sheet

1-a: board

1-b: board

2: laser

3: melting section

4: Docking Department

5: Track

6: Track

7: Laser oscillator

8-1: Motor

8-2: Motor

9-1: Current mirror

9-2: Current mirror

10: Condenser lens

11: end (plate)

G: docking interval

W: amplitude

[FIG. 1] is a schematic diagram of the cross section of the docking portion when the laser aiming position is shifted.

[FIG. 2] is a schematic view of the cross section of the butt joint when the butt spacing is wide.

[FIG. 3] is a schematic diagram of a current scanner laser welding method. The laser welding method irradiates the butt joints of two plates in such a way that the current scanner draws a spiral or snake-shaped trajectory.

[Figure 4] Schematic diagram of a current scanning head type laser processing machine.

[FIG. 5] A graph defining the docking interval and laser amplitude of the present invention.

The butt-weld laser welding method of the steel plate and the laser-welded component welded by the laser welding method in the present invention will be described in detail. In addition, in this specification, the notation A~B (A and B are arbitrary numbers) means A or more and B or less. First, FIG. 4 schematically shows a current scanner laser processing machine. The laser 2 generated by the laser oscillator 7 is reflected by a current mirror (Galvano mirror) 9-1, 9-2 mounted on the motor 8-1, 8-2, and is irradiated to two plates through a condenser lens 10 1,1的对接部4。 4. The butt joint portion 4. The current mirrors 9-1, 9-2, motors 8-1, 8-2, and condenser lens 10 are collectively referred to as current scanning heads. The current scanning head is based on instructions from a control device not shown, and the current mirrors 9-1, 9-2 are shaken at specific speeds and angles by the motors 8-1, 8-2, and can be Combining this shaking and the conveying speed of the sheets 1, 1 makes the laser 2 draw a spiral track 5 (Figure 3a) or a serpentine track 6 (Figure 3b) as shown in FIG. The following describes the butt laser welding conditions in the laser welding method of the present invention.

5 is a diagram for explaining the present invention, and the butt portion 4 of the two plates 1, 1 is viewed from the cross-sectional direction. In the present invention, as shown in FIG. 5, the laser scanner irradiates the laser 2 to the butt portion 4 of the two plates 1, 1. The laser 2 is irradiated while drawing a spiral or snake-shaped locus 5, 6 as shown in FIG. 3 with an amplitude W equal to or greater than the docking interval G of the docking portion 4, thereby making it even to the docking portion 4 The existence of the gap can still make the two plates 1,1 penetrate through. In addition, even if the aiming position of the laser 2 is not strictly controlled, the penetration can be stably performed.

In the present invention, the butt portion 4 of the two plates 1 and 1 is melted for welding without filler, but in the present invention, the butt interval G of the butt portion 4 is greater than 0 and 2.0 mm. under. If the butt gap G is greater than 2.0 mm, the volume of the sheet material 1 that can be melted by the laser 2 becomes smaller, the thickness of the welded portion becomes thinner, the joint strength becomes lower, and the molten metal sags.

The amplitude W of the laser 2 with respect to the welding line is within the range of the following formula (1). G/2 refers to the distance from the center of the butt portion 4 shown by a chain line to the end portion 11 of the plate in FIG. 5. In addition, G/2+2.0 refers to the 2.0 mm position on the plate side from the end 11 of the plate. That is to say, in the present invention, the amplitude W of the laser 2 is limited to the distance from the center of the butting portion 4 to the distance from the end 11 of the plate to the distance not less than 2.0 mm from the end 11 of the plate. In addition, although the end portion 11 of the plate is drawn as a straight line in the schematic diagram in FIG. 5, in fact, minute irregularities are formed by the cutting method shown in FIGS. Therefore, in the present invention, the distance G between the butt joints refers to the distance between the end 11 of the sheet material and the most protruding portion of the butt joint 4.

G/2≦W≦G/2+2.0... (1) where W: laser amplitude (mm)

G: docking interval (mm).

If the amplitude W of the laser 2 is smaller than G/2, the laser 2 will pass through the docking portion 4. In addition, if the amplitude W of the laser 2 is equal to or greater than G/2+2.0, the end portion 11 of the sheet 1 will be insufficiently melted. Therefore, in the present invention, the amplitude W of the laser 2 is limited to the range of the above formula (1). In addition, the amplitude W of the laser 2 is controlled within the range of the formula (1) at the angle at which the current mirrors 9-1 and 9-2 swing.

The type of laser 2 in the present invention is not particularly limited. Carbon dioxide gas laser with relatively large output, yttrium aluminum garnet (YAG) laser, optical fiber laser, flake laser, etc. can be used. Among them, the optical fiber laser and the sheet laser are transmitted by optical fibers, and the quality of the laser beam is good, so it is preferable. In addition, The laser output is 2~7kW, and the laser beam diameter can be appropriately selected according to the type and thickness of the plates to be welded.

The laser 2 draws the trajectory of the laser 2 at a specific cycle, so that the welded portion of the two plates 1, 1 butted and welded periodically changes along the welding direction. The trajectory of the laser 2 may be, for example, a spiral shape or a serpentine shape. If it is a periodic shape, the shape of the trajectory of the laser 2 may not be particularly limited.

The flatness of the spiral, the spiral pitch, or the meandering pitch may not be particularly limited. For example, as the trajectory period of the laser 2, whether it is a spiral shape or a snake shape, it can be set to more than once per 1 cm welding direction. That is to say, every 1cm welding direction corresponds to laser two round trips between two plates 1,1 more than once. The upper limit of this period depends on the performance of the current mirrors 9-1, 9-2, and may be, for example, 100 times or less. The specific period for marking out the laser 2 can be set by a tensile test so that the welded part does not break and the base material breaks.

The welding speed (moving speed of the material to be welded) may be, for example, 0.5 to 3 m/min. The above welding conditions can be appropriately selected according to the type and thickness of the material to be welded. The amplitude, the flatness of the spiral, and the distance between the trajectories are controlled by the shaking angle, shaking speed, and welding speed (moving speed of the material to be welded) of the current mirrors 9-1 and 9-2.

In the present invention, the types of materials to be welded are not particularly limited. For example, low carbon steel, stainless steel, or these steel materials may be coated with Zn-based coating, Al-based coating, Zn-Al-based coating, Al-Si-based alloy coating, Zn-Al-Si-based alloy coating, Zn- Al-Mg-based alloy coating, Zn-Al-Mg-Si-based alloy coating, etc. In addition, the invention is not limited to steel materials, but non-ferrous metals such as Al and laser welding of steel materials and non-ferrous metals can also be applied. In addition, the method of cutting the material to be welded is not limited. General cutting methods such as shearing can be used. In addition, it can also be trimmed by mechanical grinding after cutting.

In the present invention, the thickness of the board 1 may be, for example, 1 to 6 mm. It is not limited to a plate shape, and may be a block shape. In addition, the two sheets are not limited to materials of the same thickness, but can also be materials of different thicknesses.

[Example]

的最大輸出7kW的光纖雷射焊接機來進行對接雷射焊接。 As shown in Table 1: low carbon steel; molten Zn-6 mass% Al-3 mass% Mg plated steel plate with a coating amount of 90 g/m ² per one-sided coating; SUS304; Al plate, etc. for testing Material, using the current scanning head as shown in Figure 4, and the laser beam diameter is 0.5mm

The optical fiber laser welding machine with a maximum output of 7kW is used for butt laser welding.

Laser welding was performed on the butt joints of the test materials as shown in Table 1, and the butt gap G was 2.0 mm or less of the present invention; and 2.0 mm or more for comparison. Laser welding is to install a master device directly in front of the current scanning head to detect the center position of the butt joint 4 and the butt gap G, and control the amplitude of the laser 2 within the scope of the present invention to perform butt welding. In addition, for comparison, butt welding is performed when the amplitude W of the laser 2 is outside the scope of the present invention. From the samples after butt welding, a sample for a tensile test with a width of 30 mm was sampled and subjected to a tensile test. In the tensile test, if the base material is broken, the evaluation side is ○, and if the welded part is broken, the evaluation side is ×.

The laser welding conditions and tensile test results are shown in Table 2.

[Table 2]

As shown in Nos. 1 to 20 of Table 2, in the examples of the present invention, the base material was broken, and excellent weld strength was obtained.

On the other hand, in Comparative Examples No. 21 and 22 in which the butt gap G is greater than the scope of the present invention, since the laser 2 passes through the butt portion 4 and cannot be welded, a tensile test was not performed. In Comparative Examples No. 23, 25, 27, and 29, the amplitude W of the laser 2 is lower than the range of the present invention, and the laser 2 cannot be welded through the butt portion 4, so the tensile test was not performed. In Comparative Examples No. 24, 26, 28, and 30, the amplitude W of the laser 2 is larger than the range of the present invention, so the penetration is insufficient, and the welded part is broken in the tensile test.

[Industry utilization]

The present invention can be applied to the method of welding sheets 1 and 1 by welding sheets 1 and 1 while they are butt welded to each other, even if a gap occurs in the butt portion 4 and the sheets 1 are melted to fill the gap. The present invention is also suitable for joining parts in the automobile field or industrial machine field.

1: Sheet

2: laser

4: Docking Department

11: end (plate)

G: docking interval

W: amplitude

Claims (2)

A laser welding method for steel plates, which uses no fillers to irradiate the butt joints of the two plates in a spiral or serpentine shape, and in the laser welding method, the thickness of the plates is 1 to 6 mm; The laser trajectory is drawn at a specific cycle so that the welded part of the two plates that are butted and welded periodically changes along the welding direction; the specific cycle is set by performing a tensile test so that the welded part does not The base material is broken; the laser output is 2~7kW, and the welding speed is 1~2m/min; and the butt interval G is greater than 0 and less than 2.0mm, and the laser amplitude W relative to the welding line is Within the range of the following formula (1), G/2≦W≦G/2+2.0 (1) Among them, W: laser amplitude (mm) G: docking interval (mm). A laser welding part welded by a laser welding method, wherein the laser welding method is such that the filler is not used, and the laser irradiates the butt portion of the butt jointing two plates in a spiral or serpentine shape, and the laser welding method Among them, the thickness of the plate is 1~6mm; the laser trajectory is drawn in a specific cycle so that the welding part of the two plates butted and welded periodically changes along the welding direction; The specific period is set by conducting a tensile test so that the welded part is not broken and the base material is broken; the laser output is 2~7kW, and the welding speed is 1~2m/min; and the docking interval G is greater than 0 and It is 2.0 mm or less, and the laser amplitude W relative to the welding line is within the range of the following formula (2), G/2≦W≦G/2+2.0 (2) where W: laser amplitude ( mm)G: docking interval (mm).

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