JP2001334377A - Method of butt welding using laser beam and arc - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of a butt welding using a laser beam by which a working time is shortened while keeping a high welding quality in a butt welding where the laser beam and an arc are used. SOLUTION: In the present invention, an attention is paid to the fact that the opening part on the heat input side of a cut part becomes larger than the opening part of an opposing side face and a Y-shape is almost formed in the cross section when a plate is cut by using a gas or the like. End faces 7a1 and 7b1 on the heat input side are butted to each other when members to be welded 7a and 7b are cut by using a gas or the like, and the end faces of the butted faces are butted with a Y-shaped gap, as shown in (A) in Fig. 1. As shown in (B) and (C) in Fig. 1, the face side where the gap of the members to be welded 7a and 7b is larger is irradiated with the laser beam 1 and the arc and the butt welding is performed. As shown in (D) in Fig. 1, the welding is performed by jointly using the laser beam and the arc, where a laser beam induced plasma 6 introduces an arc plasma 8 into the deep bottom of the groove, the plasma is generated in the deep position and a deep penetration is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butt welding method in which a material to be welded and a material to be welded are butt welded to each other using a laser and an arc.

[0002]

2. Description of the Related Art Lasers have a high energy density and are excellent as a means for thermal processing. However, large output lasers capable of obtaining a deep penetration of 10 mm or more are still unreliable and expensive.

On the other hand, arc welding is inexpensive and can be handled relatively easily. However, in order to obtain deep penetration, the amount of heat input becomes large, causing problems such as distortion.

In recent years, in butt welding,
Laser welding and arc welding are used in combination, and a method for obtaining deep penetration by sharing heat input between the laser and the arc has been attempted, but in order to effectively combine the laser and the arc, Various attempts have been made.

[0005] For example, in a butt welding method using both a laser and an arc disclosed in Japanese Patent Application Laid-Open No. 10-216972, a distance between a laser irradiation position and a target position of a welding wire of the arc is set. The welding material and the material to be welded are separated from each other without being brought into close contact with each other, and a root gap is provided.

By setting this root gap to be equal to or more than 10% of the thickness of the material to be welded and equal to or less than the laser beam diameter, butt welding of a thick plate can be performed at high speed.

However, simply providing a root gap as in the method disclosed in Japanese Patent Application Laid-Open No. Hei 10-216972 does not allow the arc to enter the inner surface of the root if the root gap is relatively narrow. An arc is generated on the surface of the welding material.

[0008] The arc generated on the surface of the material becomes a plasma state in which metal vapor and gas molecules are dissociated into cations and electrons, and the laser is absorbed and scattered by the plasma.

Therefore, the energy loss of the laser is large and it is difficult to obtain deep penetration.

Further, when the root gap is increased in order to cause the arc to enter the inner surface of the route, a laser beam passing through a widely formed root gap is characterized in that a focal point having a diameter of 1 mm or less is minute. As a result, the effect of the laser is lost and the penetration depth becomes about the same as the arc alone, so that deep penetration cannot be obtained.

Further, since the penetration is obtained by melting the material to be welded in the thickness direction, the ability to melt the material to be welded with a deep penetration depends on the laser output. Therefore, the limit thickness at which butt welding is possible is determined by the output of the laser, and it is difficult to perform butt welding of a thick plate having a laser output or more.

In order to obtain a deeper penetration than the limit of the laser output, Japanese Patent Laid-Open No. 7-32338 discloses a conventional technique.
No. 6 is disclosed.

In the technique described in this publication, a Y groove is provided at the time of butt welding, that is, the end of the material to be welded is processed so that the opening on the laser heat input side is wide and narrow toward the opposite side. When a predetermined width is reached, a straight portion is formed at the interval, and the butted portion is processed so as to have a Y-shape.

The Y-shaped butt portion can be divided into a V-shaped portion and an I-shaped portion, that is, a straight portion.
This is a method of filling the groove of the mold by arc welding.

[0015] With this arrangement, the thick plate can be butted with high quality by using the laser and the arc.

[0016]

However, in the prior art for forming the Y-groove described above, the end of the material to be welded is brought into contact with the ends of the material to be welded.
Processing must be performed by a milling machine or the like so as to form a Y-shape, and there is a disadvantage that the entire working time is lengthened by this processing step.

[0017] For this reason, the processing step for making the material to be welded into a Y-shape has become a hindrance to shortening the working time in butt welding of thick plates using a laser and an arc.

An object of the present invention is to realize a butt welding method using a laser capable of shortening the working time while maintaining high quality welding in a butt welding using a laser and an arc. It is.

[0019]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. When a plate material is cut by using gas, laser or plasma, the cut portion is inserted. The attention is paid to the fact that the opening on the heat side is larger than the opening on the surface on the opposite side, and the cross section is substantially Y-shaped.

In order to achieve the above object, the present invention is configured as follows. (1) In a butt welding method using a laser and an arc, cutting is performed using a gas, plasma, or a laser.
The two materials to be welded are joined together with their cut end faces facing each other such that the surface on the heat input side at the time of cutting is one surface side and the surface on the heat input side is the other surface side. Heat input is started by a laser and an arc from one surface side, which is the surface on the heat input side at the time of the cutting, of the cut end surfaces of the two materials to be opposed to each other, and butt welding of the materials to be welded is performed.

Since the cut end faces of the two materials to be cut, which are cut by using gas, plasma or laser, have a substantially Y-shape, the cut end faces of the materials to be welded are opposed to each other, butted and inserted. If butt welding is performed by laser and arc from one side which is the hot side,
Deep penetration welding can be performed without performing beveling, and the beveling process can be omitted.

Therefore, in butt welding using a laser and an arc, while maintaining high quality welding,
A butt welding method using a laser and an arc that can shorten the operation time can be realized.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an explanatory view of a butt welding method using a laser and an arc according to an embodiment of the present invention. FIGS. 2 and 3 show a case where a plate material is cut using a gas, a laser, or a plasma. It is explanatory drawing of a cut surface.

In FIG. 2, the plate 4 to be cut is cut into one member 4a and the other member 4b by the gas, laser or plasma. 4a1 is one member 4
a cutting opening end surface of the heat input side surface at the time of cutting a,
4b1 is a cutting opening end face on the heat input side surface when the other member 4b is cut.

Reference numeral 4a2 denotes a cutting opening end face on the side opposite to the heat input side when one of the members 4a is cut;
Reference numeral 4b2 denotes a cut opening end face on the side opposite to the heat input side when the other member 4b is cut.

As shown in FIG. 2, the distance between the opening end faces 4a1 and 4b1 on the heat input side is larger than the distance between the opening end faces 4a2 and 4b2 on the side opposite to the heat input side, and When viewed from above, it has a substantially Y-shape.

As shown in FIG. 3, the cut surface 4a3 of the member 4a has a plurality of grooves formed from the open end surfaces 4a1 to 4a2.

Therefore, when butt welding is performed on a plate material cut using gas, laser or plasma, if the heat input side surfaces at the time of the cut are arranged so as to be the same surface, the butt portion can be obtained. The end face of
They are opposed to each other with a character-shaped gap.

Thus, when the plate-like members having the Y-shaped gaps formed and arranged as described above are heated by a laser and an arc from a large direction, these plates can be melted together with deep penetration. , Good welding can be performed.

Next, a butt welding method using a laser and an arc according to an embodiment of the present invention will be described with reference to FIG.

First, in FIG. 1A, the workpieces 7a and 7b cut by using a gas, a laser, or a plasma.
Between the heat input side end faces 7a1 and 7b1 when these materials 7a and 7b are cut, and the end face 7 opposite to the heat input side.
a2 and 7b2 are arranged so as to face each other.

The end faces of the butted portions of the workpieces 7a and 7b face each other with a Y-shaped gap.

Next, as shown in FIGS. 1 (B) and 1 (C), the laser 1 is irradiated from the surface side where the gap between the workpieces 7a and 7b butted against each other is large, that is, from the heat input side at the time of cutting. And an arc is given to start butt welding.

Reference numeral 2 denotes a MIG torch, and reference numeral 3 denotes a shielding gas. The shield gas 3 is injected coaxially from the MIG torch 2 to the workpieces 7a and 7b.

As shown in FIG. 1 (D), as a phenomenon when the laser and the arc are used in combination, the arc plasma 8 is formed by the rigidity of the arc (the force that causes the arc to come straight out of the electrode). The laser beam is applied to the molten pool that descends below the surfaces of the workpieces 7a and 7b and sinks below the surfaces of the workpieces 7a and 7b generated there.

Then, the laser plasma 6 of the laser 1 guides the arc plasma 8 to the bottom of the groove and generates plasma at a deep position inside the groove, whereby the keyhole 5 is formed and deep penetration is obtained. Can be

In this case, even if the thickness of the materials 7a and 7b to be welded is large, the laser 1 guides the arc plasma 8 deep inside the groove, so that penetration into the groove bottom is obtained. Further, the focus position of the laser 1 is changed to the laser 1
Is formed inside the groove so as not to interfere with the openings of the materials 7a and 7b to be welded, so that a concentrated heat source is injected into the groove, thereby obtaining deep penetration.

As described above, the cut surface of the plate material cut by the gas, laser, or plasma is not vertical, but naturally becomes tapered, and the tapered cut surfaces are used as grooves of the butted surfaces. By utilizing and welding, deep penetration welding can be performed without performing groove processing.

Therefore, according to one embodiment of the present invention, in butt welding using a laser and an arc, a laser and an arc that can shorten the working time while maintaining high-quality welding are used. The butt welding method used can be realized.

It should be noted that the above-described examples are based on the work pieces 7a and 7b.
Is an example in which the sheet thicknesses are substantially equal to each other, but the present invention is also applicable to butt welding of materials to be welded having different sheet thicknesses.

That is, as shown in FIG.
a, 7b, the heat input side end faces when cut, and the heat input side opposite end faces are arranged so as to face each other,
If butt welding is performed by applying a laser and an arc from the surface side (heat input side during cutting) where the gap between the workpieces 7a and 7b butted to each other is large, the workpieces having different plate thicknesses are provided. It is also applicable to butt welding of 7a and 7b, and the same effect as described above can be obtained.

[0042]

According to the present invention, attention is paid to the fact that the end face of the plate material cut by gas, plasma or laser is a tapered end face in that state. The heat-side end faces are arranged so that the end faces on the side opposite to the heat input side face each other, and the face side where the gap between the materials to be welded to each other is large, that is, the heat input side at the time of cutting Butt welding is performed by giving a laser and an arc.

Therefore, there is no need for beveling,
In a butt welding using a laser and an arc, a butt welding method using a laser and an arc that can shorten the operation time while maintaining high-quality welding can be realized.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a butt welding method using a laser according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a cut surface when a plate material is cut using gas, laser, or plasma.

FIG. 3 is an explanatory diagram of a cut surface when a plate material is cut by using gas, laser, or plasma.

FIG. 4 is an explanatory diagram in a case where the present invention is applied to welding of plate materials having different plate thicknesses.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser 2 MIG torch 3 Shield gas 4a, 4b Welded material 4a1, 4b1 Heat input side end surface 4b1, 4b2 Opposite end surface 5 Keyhole 6 Laser plasma 7a, 7b Welded material 7a1, 7b1 Heat input side end surface 7a2, 7b2 Opposite Side end face 8 Arc plasma

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Naoki Miyanagi 650, Kandate-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. Tsuchiura Plant (72) Inventor Yutaka Takano 650, Kandate-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery F-term in Tsuchiura Plant (reference) 4E001 AA03 BB08 BB12 4E068 BC01 BE00 BE03 DA14

Claims (1)

[Claims] 1. A butt welding method using a laser and an arc, wherein two pieces to be welded cut by using gas, plasma, or laser are heat-input side surfaces at the time of cutting are connected to one surface side. Then, the cut end faces of the two materials to be welded are opposed to each other so that the face on the heat input side is the other face side. A butt welding method using a laser and an arc, wherein heat input is started by a laser and an arc from one side of the surface, and the butt welding of the material to be welded is performed.