JPH07132386A - Method for butt welding of sheets of different thickness - Google Patents

Abstract

PURPOSE:To provide an excellent weld joint with high efficiency without executing the machining to the end surface to be welded of a sheet or using a filler wire in executing the butt welding of the sheets of different thickness by a high density energy heat source such as the laser beam and the electron beam. CONSTITUTION:Sheets 1 and 2 are irradiated with the high density energy heat source 3 such as the laser beam and the electron beam by setting the irradiation angle theta relative to the butt surfaces 1a, 2a of both sheets 1 and 2 by 10-45 deg. toward the thicker sheet 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to two different plate thicknesses.
The present invention relates to a butt welding method used for butt welding a single plate material.

[0002]

2. Description of the Related Art Conventionally, when two plate materials having different plate thicknesses are butt-welded by a high-density energy heat source such as a laser beam or an electron beam, one plate material (thick plate) 1 as shown in FIG. The end faces 1a and 2a to be welded of the other plate material (thin plate) 2 are butted against each other, and the laser beam 3 is irradiated to the butted portion from the vertical direction, and the welding is performed by scanning along the butted surface. .

In such butt welding, the beam diameter of the welding laser beam 3 at the welding point varies depending on the type of processing machine and welding conditions, but is generally 150 to 6.
Since the size is 00 μm, it is necessary to control the gap G when the plates 1 and 2 are butted to each other to be equal to or smaller than the beam diameter.

That is, as shown in FIG. 4 (a), when a gap G exceeding the beam diameter is opened at the abutting portion between the plate members 1 and 2, the laser beam 3 is used as the plate member. Since the laser beam 3 escapes downward without hitting 1 or 2, a part of the energy of the laser beam 3 is lost, the melting amount of the plate material 1 or 2 is reduced, and penetration failure occurs in the welded portion. Even if the gap G is successfully controlled, as shown in FIG. 4B, when the welded end faces 1a and 2a of the plate materials 1 and 2 are not cut at right angles, the amount of molten metal is insufficient. Then
As shown in Fig. 5, unevenness and dents occur on the weld surface,
Such steps and dents have a great adverse effect not only on the appearance of the welded portion, but also on the strength of the welded joint, especially on the fatigue strength.

Therefore, only by shearing with a cutting machine, the cross-sectional shape after cutting is not constant due to wear of the cutting edge, the linearity of the cutting surface is impaired, and burrs are generated to cut at a right angle to the plate surface. Since it becomes impossible, after cutting the plate materials 1 and 2 by shearing, the welded end faces 1a and 2 of the plate materials 1 and 2 are cut.
The gap G is made small by subjecting a to a machining finish, or a filler wire is used for welding in order to secure the amount of molten metal.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In order to give the machined finish to the welded end faces 1a and 2a of No. 2 and No. 2, a machining process is added during the production process, so that there is a problem that the production cost greatly increases. When using, not only the material cost rises according to the amount of filler wire used, but also energy is needed to melt the filler wire, the welding speed decreases, and the productivity drops. However, the solution of these problems has been one of the problems for improving the efficiency of the butt welding of the plate materials having different plate thicknesses by the high-density energy heat source and rationalizing the welding process.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems in butt welding of plate materials having different plate thicknesses by a high-density energy heat source such as a laser beam or an electron beam. Butt welding that does not require machining of the welded end surface of the plate material or the use of filler wire at the time of welding, and can obtain a good welded joint with no steps or recesses in the welded portion with high efficiency It is intended to provide a way.

[0008]

According to the butt welding method of plate materials having different plate thicknesses according to the present invention, when the high density energy heat source is applied to the butting portions of the plate materials having different plate thicknesses for welding, the high density energy heat source is used. Is configured to irradiate the butt surface of the plate material by inclining it to the thick plate side of 10 to 45 °, and a means for solving the above-mentioned conventional problems in the structure of such a butt welding method. I am trying.

In the butt welding method according to the present invention,
The irradiation angle of the high-density energy heat source with respect to the abutting surfaces of both plate materials is defined in the range of 10 to 45 ° because the irradiation angle is 10
If it is less than °, the substantial effect of irradiating the energy heat source with inclination cannot be obtained, the melting amount of the plate material on the thick plate side decreases, the molten metal amount becomes insufficient, and the welded part has a step difference. Or due to the formation of concave portions. On the contrary, when the irradiation angle exceeds 45 °, the high-density energy heat source is directed in the width direction of the plate material, and as a result, a penetration defect D occurs in the welded portion as shown in FIG.

In order to further enhance the effect by utilizing the features of the butt welding method for the plate materials having different plate thicknesses according to the present invention, the butt welding method is applied so that the plate thickness of the thick plate side plate material is 6 mm. Below, it is desirable to apply to a welded joint in which the plate thickness ratio of the thin plate to the thick plate is 7/8 or less.

This is because when the plate thickness on the thick plate side exceeds 6 mm, it becomes difficult to set the welding conditions, and defects such as poor penetration easily occur at the welded portion, and thus the plate thickness ratio of the thin plate to the thick plate is increased. If it exceeds 7/8, there is no substantial difference in plate thickness between the thick plate and the thin plate, and even if the difference in plate thickness between the thick plate and the thin plate is melted, the processing accuracy of the end face to be welded will be poor. This is because it becomes impossible to compensate for the shortage of the molten metal amount based on the above.

[0012]

In the butt welding method for plate materials having different plate thicknesses according to the present invention, a high-density energy heat source such as a laser beam or an electron beam is applied to the butt surface of the plate materials having different plate thickness by 10 to 45 ° Since the high-density energy heat source is first irradiated to the thick plate side of the plate material, even if there is a gap in the abutting portion between the plate materials, the energy is lost due to this. Instead, the energy of the high-density energy heat source is absorbed in the thick plate side of both plate materials, and the difference in plate thickness between the thin plate and the thin plate is melted at an angle, so the step difference due to the difference in plate thickness is eliminated, and the filler Since the amount of molten metal increases without using a wire, even if there is a gap in the butt part due to poor processing accuracy of the welded end faces of both plate materials, the filler wire is also used. Is sufficient molten metal amount not secured, sound welds without such depressions will be formed.

[0013]

EXAMPLES The present invention will be specifically described below based on examples.

A plate material 1 (plate thickness t ₁ = 1.2) made of a cold rolled steel plate SPCEN material specified in JIS G 3141.
mm) and a plate material 2 made of the same kind of steel plate (plate thickness t ₂ = 0.6
mm) is prepared, and as shown in FIG.
A and 2a were butted and set in a laser welding machine equipped with a CO ₂ laser oscillator having an output of 5 kW. It should be noted that the welded end faces 1a and 2a of both the plate materials 1 and 2 are both cut by shearing,
As a result of actual measurement, a maximum gap of 0.8 mm was formed between the end faces 1a and 2a to be welded.

The laser beam 3 for the abutting surface
Butt welding was performed under the conditions of a beam diameter of 580 μm at the welding point, a processing output of 3.5 kW, and a welding speed of 3.5 m / min after adjusting the irradiation angle θ of No. 2 to 27 °.

As a result, as shown in FIG. 1 (b), a sound welded portion having a good external shape that gently inclines from the thick plate 1 side to the thin plate 2 side and having no internal defects is provided. It was confirmed that the butt-welded joint had good productivity and could be easily obtained.

[0017]

As described above, the butt welding method for plate materials having different plate thicknesses according to the present invention has the above-mentioned configuration, that is, a high-density energy heat source such as a laser beam is 10 to 45 ° with respect to the butt surfaces of both plate materials. Since the irradiation is performed by inclining to the thick plate side, the plate thickness difference part of the plate material on the thick plate side, especially with the thin plate, will be melted intensively,
Since it is possible to compensate for the shortage of molten metal amount due to poor processing accuracy of the welded end surface, the appearance and strength can be improved without machining the welded end surface of both plate materials and without using filler wire. It has an extremely excellent effect that a sound welded joint having no problem can be obtained.

[Brief description of drawings]

FIG. 1 (a) is an explanatory view showing a welding procedure according to an embodiment of a butt welding method for plate materials having different plate thicknesses according to the present invention. (B) It is a copy drawing which shows the cross section of the welded joint welded by the point shown in FIG. 1 (a).

FIG. 2 is an explanatory diagram showing a cross-sectional shape of a welded joint when an irradiation angle of a high-density energy heat source exceeds 45 °.

FIG. 3 is a perspective explanatory view showing a conventional example of butt welding of plate materials having different plate thicknesses by a high-density energy heat source.

4 (a) and 4 (b) are explanatory views showing an example of the shape of an end face to be welded, which is inferior in processing accuracy.

FIG. 5 is a copy diagram showing a cross section of a welded joint according to a conventional welding method.

[Explanation of symbols]

 1 plate material (thick plate) 2 plate material (thin plate) 3 laser beam (high-density energy heat source)

[Procedure amendment]

[Submission date] November 12, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

FIG. 1 (a) is an explanatory view showing a welding procedure according to an embodiment of a butt welding method for plate materials having different plate thicknesses according to the present invention. (B) It is a photograph showing a metallographic structure in a cross section of a welded joint welded by the procedure shown in FIG.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

FIG. 5 is a photograph showing a metallographic structure in a cross section of a welded joint produced by a conventional welding method.

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5]

Claims (2)

[Claims] 1. When irradiating and welding a butt portion of plate materials having different plate thicknesses with a high-density energy heat source, the high-density energy heat source is 10 to 45 ° with respect to the butt surface of the plate material.
A butt welding method for plate materials having different plate thicknesses, which comprises irradiating while inclining to the thick plate side. 2. The plate thickness different according to claim 1, wherein among the plate materials, a thick plate has a plate thickness of 6 mm or less, and a ratio of the thin plate to the thick plate is 7/8 or less. Butt welding method for plate materials.