JPH10156532A - Multiple electrode gas shielded metal arc welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of high-temperature cracks, to reduce the generated quantity of the spatter, and to provide excellent bead appearance even when the welding speed is as high as 100 through 300cm/min. SOLUTION: A cold wire 4 of large diameter and circular section is arranged in a part 3 to be welded of a joint to be formed by arranging two plates 1 and 2 opposite to each other in V-shape, and the welding is performed by two or more electrodes regarding a contact part of the cold wire 4 with the plate 1 and a contact part of the cold wire 4 with the plate 2 as secondary groove parts 5a, 5b. A first electrode 6 is set with a contact part (the secondary groove part 5a) of the cold wire 4 with the plate 1 as the target position, and the second electrode 7 is set with a contact part (the secondary groove part 5b) of the cold wire 4 with the plate 2 as the target position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method in which a first member and a second member are connected to each other, such as a flared joint in which the first member and the second member are curved surfaces and curved surfaces, curved surfaces and flat surfaces, or flat and flat surfaces. The present invention relates to a multi-electrode gas shielded arc welding method suitable for application to welds that cross at an acute angle, and particularly to a gas shielded arc welding method suitable for partial penetration welding of a steel pipe sheet pile, such as a P-type joint. About.

[0002]

2. Description of the Related Art FIG. 7 is a schematic view showing a conventional welding method for a steel pipe sheet pile P-type joint. As shown in FIG.
When the groove portion of the mold joint is enlarged, the base material 31 and the base material 32 form a V groove. In such welding of a steel pipe sheet pile P-type joint, generally, after filling a groove with a cut wire 34 or the like before welding, an electrode is used to secure a welding amount and improve welding efficiency. 36 is often welded with a tandem two electrode, and the joint is welded by bridging the weld metal 35 between the base material 31 and the base material 32.

In this case, a part of the cut wire 34 at the top of the groove is melted by arc heat or the heat of the molten pool to form a weld metal 35. However, it is not always necessary to melt. The first reason for this is that in order to melt all of the cut wires 34 that are filled, an extremely large heat capacity is required, so that welding efficiency is reduced. Second, it is preferable that only the effect of preventing leakage of the weld metal be obtained by the cut wire at the deep groove.
Therefore, in order to perform such partial penetration welding,
It is necessary to select appropriate welding conditions.

[0004]

However, when the filler (cut wire 34 or the like) is partially penetrated, the weld metal 35 bridged is cooled mainly from both sides of the groove, so that the welding speed is increased. Then, for example, 100 (cm
If the welding is performed at a high speed of more than (/ min), the dendrite is likely to meet at the center of the weld metal, cracks 37 are likely to occur at the center of the weld metal 35, and the amount of spatter generated is increased.

The present invention has been made in view of such a problem, and has a welding speed of 100 to 300 (cm / min).
Multi-electrode gas shielded arc welding method that can prevent the occurrence of hot cracks and reduce the amount of spatters even when high-speed welding of The purpose is to provide.

[0006]

According to a multi-electrode gas shielded arc welding method according to the present invention, a welding portion between a first member and a second member uses two or more electrodes having a first electrode and a second electrode. In the multi-electrode gas shielded arc welding method of performing welding, a cold wire is arranged in the welded portion so that a longitudinal direction thereof coincides with a welding line, and the first electrode is provided on the surface of the first member and the cold wire. The second electrode is welded with the contact portion between the second member and the cold wire as the wire target position.

When the cold wire has a circular cross section, the wire diameter is preferably 5 to 15 mm. Also, the cold wire may have an elliptical or polygonal cross-sectional shape, and if the cross-sectional shape is elliptical,
The value of (major axis + minor axis) / 2 is preferably 5 to 15 mm, and in the case of a polygon, the diameter of the circumscribed circle is preferably 5 to 15 mm.

Further, it is preferable to use a solid wire as a wire of the first electrode and the second electrode forming the first layer weld metal, and to use a third electrode or more electrodes for the second and subsequent layers. It is desirable to use one of the wires selected from the group consisting of the solid wire and the flux-cored wire as the wires after the third electrode forming the weld metal and forming the second and subsequent layers. Furthermore, the welding speed is preferably set to 100 to 300 (cm / min).

In the present invention, a large-diameter cold wire is disposed at a crossing portion of a joint consisting of a first member and a second member as a welding base material, that is, a welding portion, and formed on both sides of the cold wire. A contact portion with each base material is regarded as a secondary groove portion, and welding is performed with this as a target position. Since this secondary groove becomes substantially V-shaped and the dendrite grows obliquely upward, even if the dendrite grows from both sides of the base metal side and the cold wire side, it will meet at the center of the weld metal. It becomes difficult. Therefore, generation of cracks in the weld metal can be prevented.

[0010] Further, by welding the secondary groove, welding metal is required for bridging compared to a conventional case where a joint weld is welded without disposing a cold wire. Certain weld cross-sections can be extremely small. Therefore, the first electrode sets the contact portion between the cold wire and one base material (first member) as a target position,
By setting the contact portion between the cold wire and the other base material (the second member) as the target position, the welding speed can be increased as compared with the conventional welding method.

Further, when a solid wire is used as the wire forming the first layer of the weld metal, impurities contained in the weld metal in the first layer which affect the hot crack can be reduced, and the occurrence of the hot crack can be reduced. Can be prevented.
Furthermore, as a wire forming the second and subsequent layers of the weld metal,
For example, when a flux-cored wire is used, a good bead appearance can be obtained.

In the present invention, the first layer is defined as a portion between the first electrode and the cold wire and the other base material (second member) aiming at a contact portion between the cold wire and one base material (first member). It is the weld metal formed by the second electrode aiming at the contact portion. In the present invention, when three or more electrodes are used, the third and subsequent third and subsequent electrodes can be aimed at the joint crossing portion as in the related art.

Hereinafter, the diameter and welding speed of the cold wire used in the method of the present invention will be further described.

Cold wire diameter: 5 to 15 mm In the present invention, a cold wire is arranged at the welded portion of a welding base material so that the longitudinal direction thereof coincides with the welding line, and two cold wires are formed on both sides of the cold wire. Weld the next groove. As the cross-sectional shape of the cold wire, a circle, an ellipse, or a polygonal shape can be applied. When a cold wire having a circular cross-sectional shape is used, the diameter of the cold wire is 5 m.
If it is less than m, the secondary groove is too small to allow a wire to enter, and it is difficult to aim the groove with a wire. On the other hand, if the diameter of the cold wire exceeds 15 mm, the secondary groove becomes too large, so that it is difficult to bridge the weld metal with only one electrode. Therefore,
When using a cold wire having a circular cross section, the wire diameter is preferably 5 to 15 mm.

Welding speed: 100 to 300 (cm / min) Since the amount of welding required for bridging of the weld metal is not so large, the present invention is not applied when the welding speed is less than 100 (cm / min). No need to apply. On the other hand, if the welding speed exceeds 300 (cm / min), the humping of the first layer bead becomes excessive, which adversely affects the bead appearance of the final layer. Therefore, the welding speed is 100 to 300.
(Cm / min).

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the method of the present invention will be specifically described below with reference to the accompanying drawings.

FIG. 1 is a sectional view showing a multi-electrode gas shielded arc welding method according to an embodiment of the present invention. As a welding base material, two plate materials (a first member and a second member) 1 and 2
And a joint is formed by arranging them in a V-shape with their surfaces facing each other. In the present invention, the plate 1
A large-diameter cold wire 4 having a circular cross-sectional shape is arranged at the welded portion 3 of the joint consisting of the first and second joints 2, and a contact portion between the cold wire 4 and the plate material 1 and a contact portion between the cold wire 4 and the plate material 2 are formed. These are regarded as secondary grooves 5a and 5b. That is, the first electrode 6 sets the contact portion (secondary groove 5a) between the cold wire 4 and the plate 1 as a target position, and the second electrode 7 sets the contact portion (secondary groove) between the cold wire 4 and the plate 2. The groove 5b) is set as a target position, and welding is performed with two or more electrodes.

As described above, the first electrode 6 and the second electrode 7
However, by welding the secondary groove portions 5a and 5b, respectively, to obtain the first layer weld metal, it is necessary for the weld metal to bridge compared to the case where the original joint weld portion 3 is welded. The welding cross-sectional area can be made extremely small. Accordingly, the welding speed can be increased as compared with the conventional welding method.

FIG. 2 is an enlarged schematic view showing the state of the weld metal after welding by the method of the present embodiment. When welding is performed by the method of this embodiment, the cold wire 4 and the plate 1
And the secondary groove 5b formed by the cold wire 4 and the plate 2 are substantially V-shaped.
The groove 5a and 5b have a weld metal 2
1 and 22 are formed. When the weld metals 21 and 22 are cooled, the dendrites
, The dendrite hardly associates in the weld metal. Therefore, according to the method of the present embodiment, the occurrence of cracks in the weld metals 21 and 22 can be prevented.

In the embodiment shown in FIG. 1, two plates 1 and 2 are used as welding base materials, and an example of welding a joint consisting of flat surfaces has been described. Is not limited to this.

FIG. 3 is a sectional view showing examples of various joint shapes to which the method of the present invention is applied. For example, the joint shown in FIG. 3A includes a tubular member 8 having a curved surface and a plate-like member 9 having a plane arranged perpendicular to a tangent to the curved surface. Welded part 1 between member 9
0 is formed. The joint shown in FIG. 3 (b) is obtained by bringing the curved surfaces of two tubular members 11 and 12 having curved surfaces into contact with each other, and forms a weld 13 between the two. Further, the joint shown in FIG. 3C is a tubular member 1 having a curved surface.
4 and a plate-like member 15 arranged in contact with the curved surface
And a welded portion 16 is formed between the tubular member 14 and the plate-shaped member 15.

In the present invention, by arranging cold wires at the welds 10, 13, and 16 of the various joints thus formed, welding can be performed in the same manner as the welding method shown in FIG. .

In FIG. 1, the cold wire 4
Although an example of welding using a circular cross section has been described above, the cold wire that can be used in the method of the present invention is not limited to this.

FIG. 4 is a sectional view showing an example of the shape of a cold wire that can be used in the present invention. In the present invention, for example, a cold wire 4a having a hexagonal cross section as shown in FIG. 4A or a weld wire 3 formed between the plate material 1 and the plate material 2 or FIG. The secondary grooves 17 and 18 are formed by disposing the cold wire 4b or the like having an elliptical cross section as shown in FIG. As described above, according to the present invention, the cold wire and the plate 1 in contact with both sides thereof are provided.
And 2 can be used as long as a secondary groove is formed between them.

Further, FIG. 1 shows an example of two-electrode welding, but in the present invention, three or more electrodes can be used for welding. In this case, the third electrode (third electrode) and thereafter are used. The center of the cold wire 4 can be aimed at.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the multi-electrode gas shielded arc welding method according to the present invention will be specifically described below in comparison with comparative examples.

FIG. 5 is a sectional view showing the sizes of the plate members (first and second members) 1 and 2 used in this embodiment, and FIG. 6 is a perspective view showing the target positions of the electrodes used in this embodiment. FIG. As shown in FIG. 5 and FIG.
And 2 are arranged in a V-shape with their surfaces facing each other to form a joint, cold wires 4 of various diameters are arranged in a welded portion 3, and welding is performed with four electrodes. , Hot cracking and bead appearance were evaluated.

In this embodiment, the plate members 1 and 2 have a plate thickness of 12 mm and a plate width orthogonal to the welding line of 75 m.
m, a SM490 steel plate having a length in the welding line direction of 1000 mm was used, and the distance between the plate material 1 and the plate material 2 at the uppermost end of the welded portion 3 was 35 mm. The first electrode (L) 6 is 2
The second electrode (T1) 7 aims at the secondary groove 5b, and the third electrode (T2) 19 and the fourth electrode (T3) 20 aim at the center of the cold wire 4 at the next groove 5a. Welded.

The conditions used in each Example and Comparative Example are shown in Table 1 below, and the changed conditions are shown in Tables 2 and 3 below.
The evaluation results are shown in Tables 4 and 5 below.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

[0033]

[Table 4]

[0034]

[Table 5]

As shown in Tables 2 to 5, the embodiment N
o. In Nos. 1 to 18, the diameter of the cold wire used as the filler is within the preferable range of the present invention, and therefore, the spatter generation amount is reduced at any welding speed in the range of 100 to 300 (cm / min). Thus, the occurrence of hot cracks could be suppressed and a weld bead having an excellent appearance could be obtained.

On the other hand, in Comparative Example No. In No. 19, since the diameter of the cold wire used as the filler was less than the lower limit of the preferred range of the present invention, the amount of spatters increased and the bead appearance was poor. Some hot cracking also occurred. Also, in Comparative Example No. In Nos. 20 to 22, since the diameter of the cold wire exceeded the upper limit of the preferable range of the present invention, the amount of spatters could not be sufficiently reduced, high-temperature cracking occurred, and the bead appearance was poor. .

[0037]

As described in detail above, according to the present invention,
A cold wire is arranged at a joint of a joint so that a longitudinal direction thereof coincides with a welding line, and base materials (a first member and a second member) on both sides of the cold wire by a first electrode and a second electrode.
The welding speed is 1
Even with high-speed welding of 00 to 300 (cm / min), generation of hot cracks can be prevented and the amount of spatter generated can be reduced. Cold wires having various cross-sectional shapes can be used, and when the diameter is appropriately defined, high-temperature cracking and spatter generation can be sufficiently reduced, and a weld bead having a good appearance can be obtained. .

When a solid wire is used as the wire forming the first layer, the occurrence of hot cracking can be further suppressed. When a flux-cored wire is used as the wire forming the second and subsequent layers, the use of a solid wire is further improved. The bead appearance can be improved. When the welding speed is set appropriately, the bead appearance is further improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a multi-electrode gas shielded arc welding method according to an embodiment of the present invention.

FIG. 2 is an enlarged schematic view showing a state of a weld metal after welding by the method of the embodiment.

FIG. 3 is a sectional view showing examples of various joint shapes to which the method of the present invention is applied.

FIG. 4 is a cross-sectional view showing an example of a shape of a cold wire that can be used in the present invention.

FIG. 5 is a sectional view showing the sizes of plate materials (first and second members) 1 and 2 used in the present embodiment.

FIG. 6 is a perspective view showing a target position of an electrode used in the present embodiment.

FIG. 7 is a schematic view showing a conventional welding method for a steel pipe sheet pile P-type joint.

[Explanation of symbols]

 1, 2; plate material 3, 10, 13, 16, 17, 18; welded portion 5a, 5b; groove portion 4, 4a, 4b; cold wire 6; first electrode 7; 14; tubular member 9, 15; plate-like member 19; third electrode 20; fourth electrode 21, 22, 35; weld metal 31, 32; base metal 34; cut wire 36;

Continued on the front page (72) Inventor Masaharu Sato 100-1 Urakawachi, Miyama-shi, Fujisawa-shi, Kanagawa Prefecture Inside Fujisawa Works of Kobe Steel (72) Inventor Hajime Uchiyama 100-1 Urakawachi, Miyama-shi, Fujisawa-shi, Kanagawa Prefecture (72) Inventor Tomokazu Morimoto 100-1 Urakawachi, Miyamae, Fujisawa-shi, Kanagawa

Claims (7)

[Claims] 1. A welding part between a first member and a second member is formed by a first member.
In a multi-electrode gas shielded arc welding method for welding using two or more electrodes having an electrode and a second electrode, a cold wire is arranged in the welded portion such that a longitudinal direction thereof coincides with a welding line, The electrode is welded with a contact portion between the surface of the first member and the cold wire as a wire target position, and the second electrode is welded with a contact portion between the second member and the cold wire as a wire target position. Multi-electrode gas shielded arc welding method. 2. The multi-electrode gas shielded arc welding method according to claim 1, wherein when the cross section of the cold wire is circular, the wire diameter is 5 to 15 mm. 3. The multi-electrode gas shielded arc welding method according to claim 1, wherein the cold wire has an elliptical cross section. 4. The multi-electrode gas shielded arc welding method according to claim 1, wherein the cold wire has a polygonal cross section. 5. The multi-electrode gas according to claim 1, wherein solid wires are used as the wires of the first electrode and the second electrode forming the first-layer weld metal. Shield arc welding method. 6. A solid wire and a flux-cored wire using a third electrode or more electrodes to form a weld metal of the second and subsequent layers, and as the wires of the third and subsequent electrodes forming the second and subsequent layers. The multi-electrode gas shielded arc welding method according to any one of claims 1 to 5, wherein one of the wires selected from the group consisting of: 7. A welding speed of 100 to 300 (cm /
The multi-electrode gas shielded arc welding method according to any one of claims 1 to 6, wherein: