JPH05131288A - Nozzle for side shielding of laser welding - Google Patents

Abstract

PURPOSE:To enable efficient side shielding at a low flow rate by constituting the nozzle adequate for use at the time of supplying a shielding gas to a part irradiated with a laser by a side shielding system in laser welding in such a manner that the shielding gas is forcibly blown to the part irradiated with the laser. CONSTITUTION:This nozzle has a tubular gas suction part 5 which is formed at the front end of the nozzle 3A and successfully introduces the shielding to a weld zone, a hood part 6 which is communicated and connected with and to this gas suction part and covers the weld zone, and a discharge part 7 which is expanded and formed outward in order to discharge the shielding gas past this hood part 6 to the outside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to laser welding in
The present invention relates to a nozzle suitable for use in supplying a shield gas to a laser irradiation section by a side shield method.

[0002]

2. Description of the Related Art Conventionally, lap welding is performed by a laser in which steel plates are welded by irradiating a laser beam in a T-shaped or horizontally arranged state (for example, JP-A-3-13).
288). At this time, a shield gas (for example, N ₂ gas) is usually supplied to the laser beam irradiation section.

As the shield system, a coaxial shield system for supplying a shield gas coaxially with the laser beam or a side shield system for spraying the shield gas from a side of the laser beam at a predetermined angle with respect to the laser beam. and so on.

By the way, in the conventional side shield system, as shown in FIG. 3, the gas nozzle 3 is arranged so as to form an appropriate angle with respect to the laser beam 2a emitted from the laser beam machine 2 toward the steel plate 1. The shielding gas is blown from the gas nozzle 3 toward the irradiation portion (welding portion) of the laser beam 2a.

When, for example, zinc plating or a coating film is applied to the interface of the steel sheet 1, decomposition of metal vapor (plasma) or oil and fat components generated by melting the zinc plating or coating film during laser welding. The gas due to the ascends in the molten metal, but by spraying the shield gas onto the welded portion as described above, the metal vapor and gas are blown away by the shield gas and removed.

[0006]

However, in such a conventional side shield system, as shown in FIG. 3, the gas nozzle 3 is brought close to the welding position to perform the shield, but the flow of the shield gas is the welded portion. Since the laser beam 2a spreads and spreads to the periphery, the way the gas hits the irradiated portion of the laser beam 2a is unstable, and it is necessary to increase the flow rate of the shield gas, resulting in poor efficiency.

The present invention is intended to solve such a problem, and provides a nozzle in which a shield gas is forcibly blown to a laser irradiation portion and a side shield can be efficiently performed with a small flow rate. The purpose is to

[0008]

In order to achieve the above object, the laser welding side shield nozzle of the present invention comprises:
A shield gas is provided for spraying a shield gas at a predetermined angle toward a welded portion by a laser, and a tubular gas suction portion formed at a tip portion thereof for guiding the shield gas to the weld portion and connected to the gas suction portion for communication. It is characterized in that it is provided with a hood portion covering the welded portion and an exhaust portion which is formed to expand outwardly so as to discharge the shield gas passing through the hood portion to the outside.

Further, a laser irradiation opening through which the laser may pass may be formed on the upper surface of the hood to irradiate the laser toward the weld.

[0010]

In the above laser welding side shield nozzle of the present invention, the shield gas is forcibly introduced into the hood portion covering the welded portion through the tubular gas suction portion and then discharged from the exhaust portion to the outside. Therefore, the shield gas can be reliably supplied to the welded portion without diffusing, and a sufficient shielding function can be obtained with a small flow rate of the shield gas.

Further, the welded portion is covered by the hood portion, but by forming a laser irradiation opening on the upper surface of the hood portion, laser can be radiated to the welded portion and laser welding can be performed without any trouble. It

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A side shield nozzle for laser welding as an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view thereof, and FIG. 2 is a perspective view showing a state of laser welding performed by applying the nozzle. It is a figure.

In this embodiment, as shown in FIGS. 1 and 2, the gas nozzle 3A for supplying the shield gas is irradiated from the laser beam machine 2 toward the horizontal steel plate 4a of the workpiece 4 to be welded, as in the conventional case. It is arranged so that the shield gas can be blown out at an appropriate angle with respect to the laser beam 2a. The tubular gas suction pipe guides the shield gas to the welded portion of the workpiece 4 to be welded at the tip of the gas nozzle 3A. A portion 5 is formed, and a hood portion 6 that covers the weld portion is connected to the gas intake portion 5 so as to communicate therewith.

Further, the hood portion 6 has the hood portion 6
In order to discharge the shield gas that has passed through the
Are formed to expand outward.

Further, on the upper surface of the hood portion 6, a laser irradiation opening 6a through which the laser beam 2a can pass in order to irradiate the laser beam 2a from the laser processing machine 2 toward the welding portion.
Are formed.

The gas intake part 5, hood part 6, and exhaust part 7 as shown in FIGS. 1 and 2 are made of a heat-resistant metal such as copper. Since this copper reflects the laser beam, it has excellent durability in use.

The laser welding conditions of the laser processing machine 2 are, for example, a laser output of 5 kW, a ring mode, and a focus position of -3 mm, and N ₂ gas having a flow rate of 30 liter / min is used as a shield gas.

Further, in the present embodiment, a case is shown in which the horizontal steel plate 4a and the vertical steel plate 4b are T-shaped through welded by the laser beam 2a to form the workpiece 4 to be welded. The thickness is 2.5 mm, the thickness of the vertical steel plate 4b is 6 mm, the welding is performed at the processing speed of 2.5 m / min under the above-mentioned laser welding conditions, and the penetration depth of about 6 mm is obtained. In addition, in FIG. 2, 8 is a bead formed by laser welding.

With the above structure, the shield gas supplied through the gas nozzle 3A is forcibly introduced into the hood portion 6 covering the welded portion through the tubular gas suction portion 5. At this time, the metal vapor (plasma) generated by melting the galvanization or coating film accompanying laser welding and the gas due to the decomposition of the oil and fat components rise in the molten metal, but these metal vapor and gas are The shielding gas that passes through the hood portion 6 blows it off and removes it. And the hood section 6
The shield gas that has passed through is discharged from the exhaust unit 7 to the outside together with metal vapor and the like.

As described above, by using the nozzle of this embodiment, the shield gas can be surely supplied to the weld portion without diffusing, and all the supplied gas can be used for the shield, and the flow rate is small. A sufficient shielding function can be obtained with the shielding gas, and the efficiency is extremely improved.

Further, in the present embodiment, the welding portion of the workpiece 4 to be welded is covered with the hood portion 6, but the laser irradiation opening 6a is formed on the upper surface of the hood portion 6 and the laser beam is passed through this opening 6a. It is possible to irradiate the welded portion with 2a, and laser welding can be performed without any trouble.

The present invention is not limited to the above-mentioned embodiments, and is included in the scope of the present invention even if there are design changes and the like within the scope of the present invention. For example, the case where the steel plates 4a and 4b are T-shaped reflux welded has been described, but the nozzle of the present invention is not limited to this, and can be similarly applied to a welded portion in which steel plates are horizontally stacked and arranged. The same effect as that of the above embodiment can be obtained.

[0023]

As described above in detail, according to the side shield nozzle for laser welding of the present invention, the shield gas is forcibly introduced into the hood portion covering the welded portion through the gas suction portion and then the exhaust portion. Since it is discharged from the outside to the outside, the shielding gas can be reliably supplied to the welded part without diffusing.
It has the effect of efficiently shielding with a small amount of shielding gas.

Further, by forming a laser irradiation opening on the upper surface of the hood that covers the welded portion, it is possible to irradiate the laser to the welded portion, and laser welding can be performed without any trouble.

[Brief description of drawings]

FIG. 1 is a perspective view showing a side shield nozzle for laser welding as an embodiment of the present invention.

FIG. 2 is a perspective view showing a laser welding state in which the nozzle of this embodiment is applied.

FIG. 3 is a side view showing a conventional side shield system.

[Explanation of symbols]

 2 Laser processing machine 2a Laser beam 3A Gas nozzle 4 Work to be welded 4a Horizontal steel plate 4b Vertical steel plate 5 Gas intake part 6 Hood part 6a Laser irradiation opening 7 Exhaust part 8 Bead

Claims (2)

[Claims] 1. A side shield nozzle provided for spraying a shield gas toward a welded portion by a laser at a predetermined angle, and a tubular gas suction portion formed at a tip portion of the nozzle to guide the shield gas to the welded portion. And a hood portion which is connected to the gas intake portion and covers the welded portion, and an exhaust portion which is formed to expand outward so as to discharge the shield gas passing through the hood portion to the outside. Nozzle for side shield of laser welding, which is characterized. 2. The laser according to claim 1, wherein a laser irradiation opening through which the laser passes so as to irradiate the laser toward the welded portion is formed on an upper surface of the hood portion. Welding side shield nozzle.