JPH06198437A - Horizontal butt arc welding method for metallic materials having different thickness - Google Patents

Abstract

PURPOSE:To easily and surely perform horizontal butt arc welding of metallic materials having different thickness without causing weld defects such as defective welding, weld cracks and blowholes by constituting so that a welding torch is inclined in a limited angle. CONSTITUTION:When the rears of metallic materials to be welded are abutted on each other on the same horizontal surface and the difference in level of the upper surface of the metallic materials to be welded on a weld zone is made into >=0.1mm, the welding torch 4 is inclined to the metallic material side 2 to be welded having the smaller thickness at an angle of >=45 to <=87 deg. for the horizontal surface decided on the rears of the metallic materials to be welded to perform welding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal butt arc welding method for metal materials of different thicknesses, which are metal tubes, metal plates, metal strips and other metal structural materials having different wall thicknesses, which are horizontally butted and arc welded. Regarding the method.

[0002]

2. Description of the Related Art When metal parts to be welded having different wall thicknesses are abutted with each other and horizontal butt arc welding is performed with a step on the upper surface, the melting of the lower part of the metal part to be welded, which is particularly thick, is poor. There was a problem that welding defects such as welding cracks, non-welding, and blowholes were often generated.

In order to deal with this kind of problem, the following method and apparatus have been disclosed. (1) Japanese Patent Application Laid-Open No. 52-92841 discloses an arc welding method for a metal body of different thickness by disposing an intermediate thick body. (2) Japanese Patent Application Laid-Open No. 60-6273 discloses a welding method for a metal body of different thickness in which the trailing end of the leading coil and the leading end of the trailing coil are made uniform by press working and then welded. (3) Japanese Patent Application Laid-Open No. 61-176490 discloses a laser welding method for a metal material of different thickness in which a strip having a larger thickness is diagonally processed to eliminate a step and then welded. . (4) Japanese Patent Application Laid-Open No. 54-29855 discloses an arc welding method and apparatus for metal materials of different thickness by swing arc welding.

[0004]

In the methods (1), (2) and (3) described above, it is necessary to specially process the abutting portion or to insert an intermediate thick body, and the special processing is required. This requires equipment and processing steps, increases equipment costs, requires extra time for processing, and increases the number of welded parts when an intermediate thick body is interposed.

Further, the method and device of the above (4) is not only a complicated and expensive device, but also a technique that cannot sufficiently solve the above-mentioned problems when the step (difference in wall thickness) is large. . The present invention provides a simple horizontal butt arc welding method for different-thickness metal materials that can solve the problems of the above-described conventional techniques and prevent the occurrence of the above-described welding defects. It is an issue.

[0006]

DISCLOSURE OF THE INVENTION The present invention is a horizontal butt arc welding method for different thickness metal materials in which metal materials to be welded having different wall thicknesses are arc-welded to each other in a horizontal butt arc welding method. When the step difference between the upper surfaces of the metal materials to be welded at the welded portions is 0.1 mm or more,
The above-mentioned problem is solved by inclining the welding torch at an angle of 45 degrees or more and 87 degrees or less with respect to the horizontal plane determined by the back surface of the metal material to be welded and welding it to the thin metal material side to be welded. Is.

[0007]

The operation of the present invention will be described with reference to FIG. 1, which shows the apparatus used in the experiments of Examples and Comparative Examples. According to the present invention, by tilting the welding torch of the arc welding machine to the side of the thin metal material to be welded when the step difference between the upper surfaces of the metal materials to be welded in the welded portion is 0.1 mm or more. The softening of thin metal to be welded is easier than that of thick metal to be welded, and the thin metal to be welded and the thick metal to be welded are evenly melted. Can be obtained. This seems to be due to changes in the current distribution and the like.

In this case, the angle θ formed by the welding torch 4 and the horizontal plane S determined by the back surface of the metal material to be welded is limited to the range of 45 degrees or more and 87 degrees or less as shown in FIG. If this angle θ exceeds 87 degrees, the effect due to the inclination of the welding torch 4 cannot be obtained, and if it is 45 degrees or less, the welding torch 4 hits the clamp device 3 or the material to be welded in a normal arc welding machine. , Welding becomes impossible. Therefore, the welding torch 4 and the horizontal plane S that can obtain the effect of uniform welding are obtained.
The range of the angle θ formed by is 45 degrees or more and 87 degrees or less.

When the step difference H between the upper surfaces of the metal materials to be welded at the welded portion is smaller than 0.1 mm, the effect of uniform welding can be obtained without applying the present invention.

[0010]

FIG. 1 is a vertical sectional side view showing a horizontal butt arc welding machine for a metal material of different thickness by MIG welding used in the embodiments of the present invention and comparative examples. That is, in FIG. 1, 1 is a thick metal material to be welded, 2 is a thin metal material to be welded, 3 is a clamping device for the material to be welded, 4 is a welding torch, and 5 is a pinch roll for welding wire supply. , 6 is a filler wire coil, 7 is a welding power supply device, θ is an inclination angle of the welding torch with respect to the horizontal plane S, and H is a step difference between the thick welded metal material 1 and the thin welded metal material 2. ,
S indicates a horizontal plane determined by the back surfaces of the metal material 1 to be welded with a large wall thickness and the metal material 2 to be welded with a thin wall thickness.

Using the apparatus shown in FIG. 1, a hot-rolled sheet of SUS-304 austenitic stainless steel having a plate thickness of 8 mm was used as the metal material 1 to be welded with a large thickness, and a metal material 2 to be welded with a thin thickness was used as the welded metal material 2. Was subjected to horizontal butt arc welding using a hot rolled plate of the same steel type having a plate thickness of 6 mm. That is,
(A) An embodiment of the present invention in which the angle θ of the welding torch with respect to the horizontal plane S is 85 degrees and the step H between the two is 2 mm.
(B) A comparative example in which the angle θ of the welding torch with respect to the horizontal plane S was 90 degrees and the step H between the two was 2 mm, and M in an Ar gas atmosphere under the welding conditions shown in Table 1 was used.
After performing IG welding, the structure of the cross section in the direction perpendicular to the welding beat and the welding defect inspection result by die check of the cross section were compared.

[0012]

[Table 1]

As a result, as schematically shown in FIGS. 3 and 4, the thickness θ in the case of the embodiment (A) in which the angle θ of the welding torch with respect to the horizontal plane S was 85 degrees and the step H between them was 2 mm Sufficient penetration and welding are observed up to the lower part in the direction, and no welding defect is found in the welded portion 8. (Fig. 3) On the other hand, the angle of the welding torch with respect to the horizontal plane S is set to 9
In the comparative example (B) in which the degree is 0 degree, the lower part in the sheet thickness direction is not sufficiently melted, and unwelded defects are present in the welded portion 8 extending from the back side of the thick 8 mm hot rolled sheet to approximately 1/3 of the sheet thickness. Part 9 is visible. (FIG. 4) Although the MIG welding apparatus was used in the example (A) and the comparative example (B), the method of the present invention can obtain good results by TIG welding or other arc welding.
It is not limited to IG welding.

[0014]

According to the method of the present invention, since the welding torch is configured to be tilted within a limited angle, horizontal butt arc welding of metal materials of different thickness can be performed easily, reliably, and with poor welding. It became possible to carry out without occurrence of welding defects such as welding cracks and blow holes.

Further, in the conventional horizontal butt arc welding of different-thickness metal plates, it was necessary to weld by increasing the output, but it becomes possible to weld at a low output, and H in the heat affected zone is achieved.
The effect of preventing AZ cracking is also obtained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view of a MIG welding machine provided with a tilting device for a welding torch used in an example.

FIG. 2 is a diagram showing a range in which a uniform welding effect can be obtained by using a step H (mm) on an upper surface of a metal material to be welded and an angle θ formed by the welding torch 4 and a horizontal plane S as variables.

FIG. 3 is a diagram schematically showing a cross section (there is no unwelded defect portion 9) of the welded portion of Example (A).

FIG. 4 is a view schematically showing a cross section (there is an unwelded defect portion 9) of a welded portion of Comparative Example (B).

[Explanation of symbols]

1 Thick metal material to be welded 2 Thin metal material to be welded 3 Clamping device for material to be welded 4 Welding torch 5 Pinch roll 6 Filler wire coil 7 Welding power supply device 8 Welded portion 9 Unwelded defect part θ Welding torch 4 between the horizontal plane S and the upper surface of the thick metal to be welded metal 1 and the thin metal to be welded metal 2 S The thick metal to be welded metal 1 and the thin metal to be welded Horizontal plane determined by the back surface of material 2

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Ryoichi Yamamoto 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Co., Ltd. Chiba Works (72) Inventor Nio Yokozawa 1 Kawasaki-cho, Chuo-ku, Chiba-shi Kawasaki Steel Co., Ltd. Chiba Steel Works (72) Inventor Yuji Sato 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Co., Ltd. Chiba Steel Works

Claims (1)

[Claims] 1. A horizontal butting arc welding method for metal materials of different thicknesses, which arc-welds metal materials to be welded having different wall thicknesses, wherein the back surfaces of the metal materials to be welded are abutted on the same horizontal surface to be welded at a welded portion. When the step difference between the upper surfaces of the metal materials is 0.1 mm or more, the welding torch is 45 degrees or more with respect to the horizontal plane determined by the back surface of the metal material to be welded, 87
A horizontal butt arc welding method for different-thickness metal materials, which is performed by inclining to a thin metal material to be welded at an angle of not more than 100 degrees and performing welding.