JPH08257754A - Submerged arc welding power supply method - Google Patents

Abstract

PURPOSE: To execute stable welding having no wire feeding defect by supplying power while holding the upper part of L shaped jig for power supply to the upper part of a torch through an insulating support jig. CONSTITUTION: An insulating body is required to be interposed between a torch 4 and power supply point 7. The power supply point 7 is placed 50-100mm upward from the tip of a contact tip 5, a cab tire cable 9 is connected to the upper part of a jig for power supply 1. By connecting to the power supply point 7 through L shaped jig l for power supply, power supply is executed while holding the upper part of L shaped jig 1 for power supply to the upper part of a torch 4 through an insulating holding jig 2. The jig 1 for power supply is made of heat resistant conductive body, preferably copper. In consideration of safety, the jig for power supply is covered with heat resistant insulating material. By this method, short circuiting and seizure of wire in torch at large heat input welding is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to submerged arc welding, and more particularly, to a power feeding method for large heat input welding used for steel frames, bridges, shipbuilding, pipe building and the like.

[0002]

2. Description of the Related Art The submerged arc welding method can use a relatively large current, and has been widely used as a high efficiency welding in the field of welding steel structures such as steel frames, bridges, ships, marine structures and pipes. However, in recent years, the number of electrodes has been increased and the heat input has been increased for the purpose of further improving the welding efficiency, and in the large heat input welding such as box column corner joint welding, the current used is a large current and the wire feed rate is Since the speed is considerably higher than in the conventional case, the rotation of the wire feeding roller also becomes high, and the wire buckling as shown in FIG.
The contacts (hereinafter referred to as wires) are also frequently occurring.

Conventionally, in a power supply method of submerged arc welding, as shown in FIG. 3, a cabtire cable 9 and a torch 4 are connected via a connecting jig 6, and the torch 4 and a contact tip 5 (hereinafter referred to as a tip) are directly connected. It was connected and power was supplied to the wire 8 from the chip 5. In this case, the cabtire cable 9 and the torch 4 are connected above the torch 4 for the purpose of protecting the cabtire cable 9 from the high temperature radiant heat generated by welding. For this reason, when the wire 8 contacts the inner wall of the torch 4 between the feeding point 7 and the tip 5, a short circuit occurs, seizure occurs, and there is a problem that wire feeding failure is likely to occur.

Therefore, the present inventors have filed Japanese Patent Application No. 6-33032.
In No. 0, short-circuit and seizure in the torch in large heat input submerged arc welding by the feeding method in the vicinity of the contact tip insulated from the torch and the feeding method passed through the insulating jig to protect the cabtire cable from welding radiant heat. Proposed a method to prevent. However, as a result of extensive studies after that, in the above technique, since the cabtire cable is passed through the insulating jig and connected to the power feeding point, there is no problem if the welding electrode is welding with one electrode or two electrodes. In multi-electrode welding with three or more electrodes, it was found that the insulation jig passing through the cabtire cable may be a hindrance and proper construction conditions may not be obtained.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a power supply method in a large heat input submerged arc welding method for preventing short circuit and seizure in a torch to prevent defective wire feeding and realize stable welding. The purpose is to do.

[0006]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a feed method for submerged arc welding with large heat input, in which the feed point is connected to a torch via an insulator, and the feed point is the tip of a contact tip. From 50 to 100 mm above, the cabtire cable is connected above the L-shaped feeding jig, and is connected to the feeding point via the L-shaped feeding jig. In the submerged arc welding power feeding method, the power is fed while the upper part of the torch is held on the torch via an insulating support jig.

[0007]

The present invention will be described below with reference to the drawings. FIG. 2 is a schematic view of a high heat input submerged arc welding electrode of the present invention, and FIG. 1 is a sectional view thereof. In the present invention, first, it is necessary to interpose the insulator 3 between the torch 4 and the feeding point 7. As a result, the wire 8 fed at a high speed is buckled, and even if the wire 8 contacts the inner wall of the torch 4, the torch 4 is insulated, so that short circuit and seizure do not occur, and good wire feeding is performed.

Next, the feeding point 7 is located at the tip 5 of the chip 5.
The position is 50 to 100 mm above A. in this case,
If the distance between the feeding point 7 and the tip 5A of the chip is shorter than 50 mm, the radiant heat during welding is large, and the feeding connection jig is likely to deteriorate. On the other hand, if the length is longer than 100 mm, short-circuiting and seizure occur between the feeding point 7 and the tip 5 as in the conventional welding electrode, and wire feeding failure occurs. In this case, the feeding point 7 is 50-100 from the tip 5A of the chip 5.
As long as the position is above mm, it may be on the tip 5 or on a torch inserted between the insulator 3 and the tip 5.

Also, the cabtire cable 9 and the feeding point 7
The L-shaped power feeding jig 1 via the is required. The feed point 7 is preferably close to the tip 5 from the viewpoint of wire feeding, while the connection point of the cabtire cable 9 is preferably located away from the welded portion for the purpose of protecting it from welding radiant heat, in order to satisfy these conditions. A power supply jig is required. The shape of the power supply jig of the present invention is L-shaped for convenience,
The shape is not limited to the L-shape as long as it satisfies this function. Regarding the material of the power feeding jig, there is no problem as long as it is a heat resistant conductor such as metal, but it is desirable to use copper in consideration of electric conductivity. In addition, it is recommended to cover the power supply jig with a heat resistant insulator for safety reasons.

Further, an insulating support jig 2 for holding the L-shaped power feeding jig 1 is required. As described above, it is desirable to separate the cabtire cable 9 from the welded portion, and the cabtire cable 9 is attached to the upper portion of the L-shaped power feeding jig 1. However, considering the weight of the cabtire cable 9, the L-shaped power feeding jig 1 is supported. Is unstable at only one part of the power supply part.
A supporting jig 2 for holding the upper portion of the L-shaped power feeding jig 1 is also required in order to avoid contact with. At this time, the support jig 2 must be made of an insulating material in order to avoid energizing the torch 4.

There is no problem as long as the insulating support jig 2 and the insulator 3 are made of an insulating resin such as phenol resin or fluororesin, or a ceramic such as alumina, silica or zirconia that can be processed.

[0012]

EXAMPLE For the steel sheet shown in Table 1, the wires shown in Table 2 and Table 3 were used.
1-pass submerged arc welding was performed using the flux. The material of the L-type power supply jig used during welding in this example was copper, and the materials of the insulating support jig and the insulator were bakelite. The flux of Table 3 is 400 ° C. × 120 after the raw material powder is granulated using water glass.
After firing in a rotary kiln under the condition of min, 1
A bond flux that was sized with 2 × 100 mesh was used.

[0013]

[Table 1]

[0014]

[Table 2]

[0015]

[Table 3]

Table 4 shows welding conditions and results in the examples of the present invention. No. 1, which is an example of the present invention. Nos. 1 and 2 were able to perform good welding by the effect of the present invention,
On the other hand, in Comparative Example No. As for Nos. 3 to 5, satisfactory welding could not be performed as described in the column of welding result.

[0017]

[Table 4]

[0018]

EFFECTS OF THE INVENTION By using the submerged arc welding power feeding method of the present invention, it is possible to prevent short circuit and seizure of the wire in the torch during large heat input welding, and to perform stable welding without defective wire feeding. The effect is very large.

[Brief description of drawings]

FIG. 1 is a sectional view of a welding electrode according to the present invention.

FIG. 2 is a schematic diagram of a welding electrode according to the present invention.

FIG. 3 is a sectional view of a conventional welding electrode.

[Explanation of symbols] 1 L-type power supply jig 2 Insulation support jig 3 Insulator 4 Welding torch 5 Contact tip 5A Tip of contact tip 6 Feeding connection jig 7 Feeding point 8 Welding wire 9 Cabtyre cable

Claims (1)

[Claims] 1. A power feeding method for high heat input submerged arc welding, wherein a power feeding point is connected to a torch through an insulator,
The feeding point is 50 to 100 m from the tip of the contact tip
m above, the cabtire cable is connected above the L-shaped power feeding jig, connected to the power feeding point via the L-shaped power feeding jig, and the upper portion of the L-shaped power feeding jig is connected. A submerged arc welding power feeding method characterized in that power is fed while being held on the torch via an insulating support jig.