JPS61255784A - Laser welding method - Google Patents

Abstract

PURPOSE:To stir forcibly a molten pool and to make possible the removal of foam by inverting the polarities of electromagnets disposed to sandwich the molten pool at every prescribed time. CONSTITUTION:A laser beam 2 is irradiated to the line to be welded of materials 1, 1 to be welded and a filler wire 10 is inserted into the molten pool 8 formed in the above-mentioned manner. Power supply devices 7, 12 are then started. The temp. of the wire 10 is increased by the current flowing between the wire 10 and the materials 1 and the wire is supplied at a prescribed rate in an arrow 13 direction. The electromagnets 3, 4 facing each other with the molten pool 8 in-between are excited upon starting of the power supply device 12 and the force acting in the prescribed direction corresponding to the direction of the current is generated. The polarities of the magnets 3, 4 are inverted by the device 12 at every prescribed time and therefore the oscillations corresponding to the repeating frequencies of which the polarities are inverted are generated in the energized part of the pool 8.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] This invention is a book relating to a laser welding method for welding materials to be welded with a laser beam while supplying a filler wire to a wire to be welded.

[Conventional technology]

FIG. 7 is a diagram showing a conventional laser welding method.

In the figure, (1) is a pair of welded materials placed with their ends in contact with each other, and (2) is the welded material (1) (1)
a laser beam irradiated to the line of contact, that is, the line to be welded,
(5) is a wire feeding device, (e) Vi filler wire αO
(7) is a power supply device, (6) is a wire reel wound with
is a holder that supports the filler wire αO so that it can be supplied to the irradiation point of the laser beam (2), and can be energized.

In such a welding device, the material to be welded (1) and the holder (b) are connected to a power supply device (7), and a laser beam (
A current is passed between the molten pool (8) formed on the wire to be welded by the irradiation in step 2) and the holder α force, and the Joule heat generated by the electrical resistance of the filler wire αO increases the temperature of the filler wire αO, causing the molten pool to rise. The supply speed of the filler wire αO to (8) is increased to improve the welding speed. In this way, by moving the irradiation position of the laser beam (2), the welding part (9
) is formed.

[Problem that the invention seeks to solve]

The conventional laser welding method is performed as described above, and it is expected that the gas bubbles (porosity) generated in the molten pool will be floated and evaporated by the natural convection of the molten pool. Therefore, there is a problem that pores may remain in the welded portion.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a laser welding method that can prevent the formation of pores by stirring the molten pool.

[Means for solving problems]

In the laser welding method according to the present invention, electromagnets are arranged on both sides of the molten pool parallel to the line to be welded, so that the polarity of the magnetic field passing through the molten pool is reversed at predetermined time intervals.

[Effect]

In the laser welding method of the present invention, the direction of the magnetic field passing through the molten pool is reversed by an electromagnet whose polarity is reversed at predetermined intervals, and the molten pool is stirred.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In Figures and Figure 2, (1), (2), (5
) to αO are the same as the conventional ones. (3) , (4
) is a pair of electromagnets arranged to move along the welding line in cooperation with the laser beam (2), and (2) is a pair of electromagnets (3) and (4) whose polarity is reversed at predetermined intervals. This is a power supply device that can supply power.

Next, the operation will be explained. In the state shown in the figure, the laser beam (2) is irradiated to the weld line of the welded material (1) (1), the filler wire α0 is inserted into the formed molten pool (8), and the power supply device t (7) is inserted. (2) Start. As a result, the temperature of the filler wire αO increases due to the current flowing between the filler wire αO and the material to be welded (1), and the supply speed can be increased, and the filler wire αO is supplied at a predetermined speed in the direction of the arrow (to) shown in the figure. On the other hand, each electromagnet (3) facing each other across the molten pool (8) when the power supply device (a) starts.
.

(4) is excited, and a force is generated that operates in a predetermined direction centered on the direction of the current, as shown in FIG. In the figure, a conductor α fathom is placed between opposing electromagnets (3) and (4), and the opposing parts of electromagnets (3) and (4) are N pole and 5FjA.
When a current is passed through the conductor α in the direction of the arrow shown in the figure, the conductor α operates as shown by the thick arrow in the figure according to Fleming's left hand rule. Therefore, when the polarities of the electromagnets (3) and (4) are reversed, the direction of operation of the conductor α is also reversed. For this reason, the polarity of each electromagnet (3) and (4) is adjusted by the power supply (a) at predetermined intervals as shown in Figures 4 and 5.
Since the polarity is reversed as shown in the figure, vibrations corresponding to the repetition frequency at which the polarity is reversed are generated in the current-carrying portion of the molten pool (8).

FIG. 6 shows another embodiment, in which an electromagnet (3) is shown.

By arranging (4) on both sides of the materials to be welded (1) and (2), it is expected that the vibration directions of the molten pool (8) will be diversified due to magnetic field interference. In the above example, the filler wire was inserted from the front in the direction of welding progress.
Even when inserted from the rear, almost the same operation can be expected.0 [Effect] As described above, according to the present invention, by reversing the polarity of the electromagnets placed between the molten pool at predetermined intervals, the molten pool Since vibration is generated, the molten pool is strongly agitated and air bubbles are removed.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the configuration of a laser beam welding method according to an embodiment of the present invention, FIG. 2 is a front view, FIG. 3 is a front view showing the principle, FIGS. 4 and 5 are operation diagrams, FIG. 6 is a front view showing another embodiment, and FIG. 7 is a perspective view showing the configuration of a conventional laser beam welding method. In the figure, (1)
is the material to be welded, (2) is the laser beam, (3), (4
) is an electromagnet, (8) is a molten pool, and αO is a filler wire. In addition, in the middle of each figure, the symbol 8Vi indicates the same or the equivalent part.

Claims (3)

[Claims] (1) A wire to be welded which is in contact with a pair of materials to be welded is melted by a laser beam to form a molten pool, and a filler wire in which a direct current is passed is supplied to this molten pool and welded along the welded wire. In the laser welding method, electromagnets that are capable of forming a predetermined magnetic field when energized are placed facing the molten pool at predetermined intervals along the welding line, and the direction of the magnetic field of the electromagnet is changed for a predetermined period of time. A laser welding method characterized by reversing each time. (2) Laser welding according to claim 1, characterized in that an electromagnet is disposed on either one of one side where the laser beam is irradiated and the other side where the laser beam penetrates the line to be welded. Method. (3) The laser welding method according to claim 1, wherein electromagnets are arranged on one side where the laser beam is irradiated and on the other side where the laser beam penetrates the line to be welded.