JPH04157079A - Laser beam welding method - Google Patents

Abstract

PURPOSE:To prevent sticking of a welding wire and the occurrence of internal defects based on this by heating the welding wire by using Joule heat and supplying it in the opposite direction to the welding direction at an acute angle with respect to the previous weld surface. CONSTITUTION:DC or AC electricity is supplied between the welding wire 3 and base metals 8 to be welded from a wire heating power source 9 via a feeder 11 and a feeding chip 10. The welding wire 3 supplied with electricity is sent into a molten pool 17 via a feed nozzle 12 by feed rollers 6. In order to obtain effect of sticking prevention and heating of the welding wire 5 and increase the quantity of deposition, the welding wire 5 is sent into the front part of the molten pool 17 at a low elevation angle from the supporting direction of the welding direction 16.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a laser welding method.

[Conventional technology]

Conventionally, in laser welding while adding welding wire,
As shown in the longitudinal cross-sectional view of FIG. A method is employed in which welding is performed by feeding the welding wire 3 fed through the feed roller 6 and feed nozzle 4 at an acute angle to the welding wire 5 .

At this time, in order to ensure the amount of welding, the welding wire 3 is fed into the molten pool 17 directly below the optical axis 5 at an acute angle to the optical axis 5 of the laser beam 1 to form a weld bead. As shown in Figure 5 (A> Longitudinal sectional view), if the base metal welding surface 19 of the welding base material 8 in the first layer of laminated feel welding is a flat surface due to mechanical processing, the set focus blur amount can be maintained and stabilized as long as the welding wire 3 is fed.

[Problem to be solved by the invention]

However, as shown in Figure (B), in the second and subsequent layers, unevenness is formed on the front layer welding surface 19a of the front layer welding bead 18a, and the plasma 20 (
Bloom child may also be indicated. ) overlap, the initially set defocus amount changes due to the unevenness of the front layer welding surface 19a, and the amount of irradiated energy reaches a change, and accordingly, energy is absorbed by the plasma 20 and the melting capacity decreases. decreases.

As a result, the penetration of the molten pool 17 decreases, and the welding wire 3 that is being fed in a stationary manner reaches the bottom of the molten pool 17 unmelted, causing the sticking phenomenon 21 and the occurrence of inherent defects 22. This inherent defect 22 degrades joint performance. Here, 6 is a feed roller that feeds the welding wire 3, and 16 indicates the welding direction.

The present invention was proposed in view of the above circumstances, and it prevents welding wire sticking and the occurrence of inherent defects due to this, and enables laser welding with a wide range of cloud cover + welding wire feeding and large welding amount. The purpose is to provide a laser welding method that enables.

[Means to solve the problem]

To this end, the present invention provides a method in which laser light is focused through a condensing lens and irradiated onto the welding base material, and welding is performed while adding a welding wire, in which the welding wire is heated using Joule heat of I''R. It is also characterized in that it is supplied at an acute angle to the welding surface of the previous layer in a direction opposite to the welding direction.

[Effect]

According to this method, the wire is fed along the welding surface of the base metal at an acute angle to the welding surface of the base metal and passes directly under the laser beam.

At this time, since a current of t is supplied from the wire heating power source between the welding wire and the welding base metal, the welding wire is heated by the Joule heat of I''R.

As a result, the welding wire will not reach the bottom of the molten pool in an unmolten state, and sticking will no longer occur, and it will be possible to perform laser welding with a large amount of welding using the welding wire of a wide range of welding properties.

〔Example〕

An embodiment of the present invention will be explained with reference to the drawings. FIG. 1 is a longitudinal cross-sectional view thereof, FIG. 2 is a cross-sectional view taken along the line -■ in FIG. 1, and FIG. 3 is a cross-sectional view of FIG. 1.

In the above figure, a laser beam 1 is focused by a condensing lens 2 and irradiated onto a welding base material 8, melting it, and feeding a welding wire 3 into it to perform laser welding. In order to carry out lamination welding 15 using the tip 14, etc., a power supply line 1 is connected between the welding wire 3 and the welding base material 8 from the wire heating power source 9.
1. Supply DC or AC power via the power supply chip 10.

Here, the powered welding wire 3 is fed into the molten pool 17 via the feeding nozzle 12 by the feeding roller 6. These are insulated from the others by a tip 13 for attaching the feed nozzle 12. The welding wire 3 is fed into the molten pool 17 at a small angle of attack from the opposite direction of the welding direction 16 to the front part of the molten pool 17 in order to prevent sticking and increase the effect of heating the welding wire 3 and increase the amount of welding. send it in.

Note that 7 indicates a gas inlet.

According to this type of laser welding, by heating the welding wire, it is possible to perform laser welding by adding a more stable amount of welding wire to the welding surface, reducing the angle of attack of the welding wire to the molten pool, and depositing a large amount of welding wire on the welding surface. By feeding the welding wire at an acute angle and heating the welding wire, it is possible to prevent the occurrence of inherent defects due to sticking.

In addition, in laser welding, there was conventionally a limit to the diameter of the welding wire that can be used, but in the present invention, since the laser beam is focused and irradiated with an extremely small diameter, it becomes possible to use a wide range of welding wire diameters.

〔Effect of the invention〕

In short, according to the present invention, in the method of welding by focusing a laser beam through a condensing lens and irradiating it onto a welding base material and adding a welding wire, the welding wire is heated using I2R Joule heat and By feeding this at an acute angle to the welding surface of the previous layer in the opposite direction to the welding direction, welding wire sticking and the occurrence of inherent defects due to this can be prevented, and welding wires of a wide range of wire diameters can be fed. The present invention is industrially extremely useful because it provides a laser welding method that enables laser welding of a large amount of welding.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line ■--■ in FIG. 1, and FIG. 3 is a cross-sectional view of FIG. 1. Fig. 4 is a longitudinal sectional view showing a known laser welding method;
Each figure is a sectional view showing the weld bead of FIG. 4. DESCRIPTION OF SYMBOLS 1... Laser light, 2... Condensing lens, 3... Welding wire, 4... Feeding nozzle, 5... Optical axis, 6...
・Feeding roller, 7... Gas inlet, 8... Welding base material, 9... Heating ms, 10... Power feeding tip, 11.
... Feed line, 12... Feeding nozzle tip, 13...
Insulating chip, ]4... Groove, 15... Welding, 16.
... Welding direction, 17... Molten pool, 18... Weld bead, 18a... Front layer weld bead, 18b... Next layer weld bead, 19... Welding surface, 19a... Front layer Welding surface, 19b...Next layer welding surface, 20...Plasma, 21
...Steph King, 22...Inherent defects, Agent: Patent attorney Masa Tsukamoto Figure 1

Claims (1)

[Claims] In this method, laser light is focused through a condensing lens and irradiated onto the welding base material, and welding is performed while adding welding wire, in which the welding wire is heated using Joule heat of I^2R and this is used for front layer welding. A laser welding method characterized by supplying at an acute angle to the surface in the opposite direction to the welding direction.