JPH09201687A - Narrow gap laser beam welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accomplish a narrow gap of joining part by irradiating a filler wire through narrow gap width with supplying a filler wire and executing build up welding from an inner part toward an outer part. SOLUTION: For example, when a thick plate 1 is butt welded, a narrow gap width 7 of a part to be welded is set narrower. A filler wire 9 is inserted into a welding part in the gap 7a. The filler wire part 9 is irradiated with a laser beam from a torch 2 through a gap 7a and a weld metal 4 is formed. Further, while the filler wire 9 is supplied to an irradiating part, a layer is formed with moving the torch 2 in the vertical direction. By repeating this, a multi-layer welding is quickly executed while building up one by one layer. Thus, the gap width 7 is made smaller as a result, welding deformation is turned to smaller, good welding is made possible and cost is reduced as well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a narrow groove laser welding method for efficiently performing welding.

[0002]

_2. Description of the Related Art In butt welding with a CO ₂ laser or a YAG laser, as shown in FIG. 2, there is a restriction on the penetration, so that a filler wire is not added to the material 01 to be welded having a plate thickness of about 5 mm. It is general to form the weld metal 04 on the.

When welding a thick plate having a plate thickness of about 50 mm with a narrow groove and welding without swinging the energy source (heat source),
TIG (tungsten inert gas) as shown in FIG.
Welding is commonly used.

In this case, the tungsten electrode 05 as the energy source is projected from the TIG torch 06 and the groove width 07 is provided.
Inserted in the groove that has the
7a is melted, a filler wire 09 is fed to the molten metal 7a, and the weld metal 04 is laminated one layer at a time to perform multi-layer welding.

[0005]

In the conventional TIG welding method, it is necessary to insert the tungsten electrode into the groove,
The energy source, or heat input, required to melt the groove depends on the diameter of the tungsten electrode.

In order to weld a thick plate with high productivity and high efficiency, the groove width is preferably as small as possible, so that the groove cross-sectional area is small.
It goes without saying that the number of welding steps can be reduced.

However, in the case of the TIG welding method, it is necessary to enlarge the electrode system in order to melt the groove, and there is a problem that the groove width is determined by the diameter of the tungsten electrode.

On the other hand, in the welding method using a CO ₂ laser or a YAG laser, it is not possible to perform welding while supplying a filler wire as in the electron beam welding.

[0009]

The present invention employs the following means to solve the above-mentioned problems.

That is, as a narrow groove laser welding method,
The welded part is set to a narrow groove width and the filler wire is supplied, while the laser torch irradiates the portion of the filler wire with the laser beam through the narrow groove width to form a layer from the inside of the narrow groove width to the front. And layer welding.

In the above, the laser beam is radiated to the tip end of the filler wire, that is, the welding location, through the space having the groove width. Since the filler wire portion is melted, the filler wire is continuously supplied, the laser beam moves, and the welding layer is formed. This is repeated, the welding layers are sequentially formed from the back to the front, and the laminated welding is performed.

In this way, the joint to be joined can be narrowed, so that the productivity is dramatically improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIG. For example, when the thick plate 1 is butt-welded, the groove width 7 of the welded portion is set to a narrow groove width. Then, the filler tube 9 is inserted into the welding location in the groove 7a. A laser beam 3 is radiated from a torch 2 arranged in front of the welding site to a filler tube 9 through a groove 7a to form a weld metal 4. Then, while supplying the filler tube 9 from the reel (not shown) to the irradiation unit, the torch 2 is moved in the direction perpendicular to the plane of the drawing to form a layer. By repeating this process, the multi-layer welding is quickly performed while laminating the layers one by one.

In this embodiment, the laser beam 3 of the YAG laser is used.
Was used. The thick plate 1 was SS400 of carbon steel plate having a plate thickness t = 50 mm.

The focus of the condenser lens in the laser torch 2 is 2.
A long focal point of 00 mm and a distance h to the irradiation unit of 20 to 3
It was set to 0 mm.

The dimension d of the groove width 7 is 2 ± 0.5 mm, which is impossible by TIG welding, and the filler wire 9 has a diameter of 1.
A 2 mm TGS-50 was used.

Although not shown, the laser oscillator employs a high-brightness slab type Nd: YAG laser and has a welding speed of 1
It was in the range of 0 to 30 cm / min.

As described above, the groove width is ⅓ of the conventional one.
It is possible to make it narrower than the following, and even if it is a thick plate, the groove cross-sectional area becomes small. As a result, the consumption of filler wire is small and it is economical, and welding man-hours can be done with 1/3 or less of the conventional Becomes Also, due to the ultra narrow groove, welding deformation is small.

[0019]

As described above, according to the present invention, since the groove width can be narrowed, the number of steps can be reduced. In addition, due to the ultra-narrow groove, welding deformation is reduced and good welding becomes possible.

[Brief description of drawings]

FIG. 1 is a system diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a conventional laser welding method.

FIG. 3 is an explanatory diagram of a conventional TIG welding method.

[Explanation of symbols]

 1 Welding material 2 Laser torch 3 Laser beam 7 Opening width 9 Filler wire

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hozumi Gota 5-717-1, Fukahori-cho, Nagasaki City Mitsubishi Heavy Industries Ltd. Nagasaki Research Institute

Claims (1)

[Claims] 1. A layer to be welded from a depth of the narrow groove width by irradiating a portion of the filler wire with a laser beam from a laser torch through the narrow groove width while supplying a filler wire with a narrow groove width of a welded portion. A narrow groove laser welding method, characterized in that the layer is welded to the front while forming a groove.