JPH07204855A - Tip holder for submerged arc welding - Google Patents

Abstract

(57) [Summary] [Purpose] For simple welding with excellent electrical conductivity and wire feedability without melting the welding nozzle and welding tip during submerged arc welding with high current and high heat input. Provide a chip holder. [Structure] A welding tip is concentrically connected to the tip of a welding nozzle, and a split-type tip holder provided with a cooling member is closely attached to the tip of the nozzle and the outer circumference of the tip. A featured tip holder for submerged arc welding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tip holder for submerged arc welding (hereinafter referred to as a tip holder) capable of achieving stable welding in large heat input welding, especially in high current large heat input submerged arc welding.

[0002]

2. Description of the Related Art Generally, in the submerged arc welding method, a granular flux is piled up on the surface of a base material, a welding wire is fed through the flux, and a contact tip (hereinafter referred to as a tip) at the tip of a current-carrying nozzle is contacted to conduct electricity. And welding is performed.

In recent years, the construction of skyscrapers has become popular in urban areas. Along with this, thick steel plates are being used more and more as steel members for steel used in buildings. The steel frame is assembled into a box column by performing corner joint welding of four steel materials. Submerged arc welding is adopted for the corner joint welding in terms of efficiency. However, as the steel plate becomes thicker, the heat input is increasing more and more for the purpose of higher efficiency.

In the welding of thick plates, a large diameter wire is used to obtain a high welding amount with a high current and a high heat input, so that the welding tip and the welding nozzle are heated to a high temperature due to the heat generation resistance of the energization and the radiant heat of the welding, and the electric conductivity is Problems are likely to occur such as bad and poor feeding, and melting of the tip and tip holder to clog the wire to make welding impossible. As a countermeasure against this, JP-A-5-77048 proposes a method of cooling from inside or outside the nozzle.

[0005]

[Patent Document 1] Japanese Patent Application Laid-Open No. 5-77048
In the water-cooling method described in Japanese Patent Publication, the energizing nozzle is water-cooled from the inside or the outside, and the tip chip is cooled by heat conduction through the part connected by the screw part, but this is not efficient and the chip itself cools. It is hard to be done. In addition, if a water channel is provided in the chip itself, the cooling effect is great, but the structure is complicated, so that the processing cost is high, and it is a consumable item but expensive. Further, if the chips or the chip holders are burnt, it is necessary to remove the chips or the chip holders for replacement. However, since the chips are burned, the removal becomes extremely difficult, and in some cases it is necessary to replace the entire torch.

The present invention provides a simple welding tip holder capable of obtaining excellent electric conductivity and wire feedability without melting the welding nozzle and the welding tip during submerged arc welding with high current and high heat input. The purpose is to do.

[0007]

SUMMARY OF THE INVENTION The gist of the present invention is that a welding tip is concentrically connected to the tip of a welding nozzle, and a cooling member is provided at the tip of the nozzle and the outer periphery of the tip. The tip holder for submerged arc welding has a structure in which a split-type tip holder is closely attached.

[0008]

The present invention will be described below with reference to the drawings. FIG. 1 is an example of a perspective view of a tip holder 5 for submerged arc welding according to the present invention, in which 2 is a cooling pipe, 4 is a water cooling plate, and 6 is a welding tip. FIG. 2 is an example of a vertical cross-sectional view showing a state in which the tip holder 5 is attached to the welding nozzle 1. The tip portion 3 of the welding nozzle 1 has a protruding structure having the same outer diameter as the rear end outer diameter of the welding tip 6, A tip tightening protrusion 7 is attached in the middle of the tip portion 3.

As shown in FIG. 3, the tip holder 5 is of a split type and has a concave structure that matches the shapes of the convex portion of the welding nozzle 1 and the welding tip 6, and corresponds to the tip fastening projection 7 and is inclined. It has a formed groove 8 and a projection 7 is formed in the groove 8.
Is inserted and rotated to press the welding tip 6 against the tip of the welding nozzle 1.

The divided end portion of the chip holder 5 has a dovetail groove structure having a taper as shown in FIG. 4 (AA 'sectional view in FIG. 2), having the water channel 2 inside, and , Insert the water cooling plate 4 with the dovetail groove into the chip holder 5,
A tip holder 5 is tightened and attached to the welding nozzle 1 and the welding tip 6 so as to be in close contact with each other.

Since the welding nozzle 1 and the welding tip 6 are closely attached to the tip holder 5 which is fastened by the water cooling plate 4, the welding nozzle 1 and the welding tip 1 are used even in the welding of large current and large heat input. The chip 6 is cooled, and the conductivity is not deteriorated by the heat generation resistance of the energization and the radiant heat of welding, and the chip 6 is not melted. Therefore, excellent electrical conductivity and wire feedability can be obtained. Furthermore, since it is a split type structure, it is easy to attach and detach.

The structure of the chip holder 5 is as follows.
As shown in FIG. 5, one side has an open / close type split structure, and the water cooling plate 4 with a dovetail groove is attached to only one side for water cooling, or as shown in FIG. 6, one side or both sides may be screwed. . For water cooling, a water channel may be provided in the chip holder 5 as shown in FIG. 6, or a water cooling pipe may be directly brazed to the outside of the chip holder.

Further, as the structure for tightening the tip 6, the welding tip 6 and the welding nozzle 1 are not seized or melted, so that the inside of the tip 3 of the welding nozzle and the tip holder 5 may be of a screw type. The material of the chip holder 5 and the water cooling plate 4 is preferably copper or copper alloy having good thermal conductivity.

[0014]

EXAMPLE A groove-shaped SM490B steel shown in FIG. 7 (plate thickness t50 mm, groove angle θ35 °, root face a2 mm,
Iron flux bond flux (grain size 12) corresponding to FS-BT1 specified in JIS Z3352 for a length of 3000 mm)
× 100 mesh) and YS-specified by JISZ3351
A wire corresponding to S1 (wire diameter: 6.4 mm) was combined and repeatedly welded 3 times under the following conditions. L pole 1900A 36V 20cm / min T pole 1500A 50V Here, the L pole is a leading electrode and the T pole is a trailing electrode.

The stability of the arc during welding and the presence or absence of melting of the welding tip and the welding nozzle were examined. The results are shown in Table 1.

[0016]

[Table 1]

In the table, No. 1 and No. 2 is an example of the present invention,
No. No. 1 shows the welding nozzle and welding tip of FIG. 1 with a water channel inside, and a water-cooled copper plate having a dovetail groove to which a tip holder is closely attached and water-cooled. In FIG. 2, the other side of the tip holder having a split structure of one side of FIG. 6 is tightened with a screw so as to be in close contact with the welding tip and the welding nozzle,
Water cooling is an example implemented by providing a water channel in the chip holder. In all of these cases, excellent electrical conductivity was obtained during welding, the arc was stable, and the welding nozzle and welding tip were not melted.

In the comparative example, No. No. 3 had a structure in which the inside of the nozzle was water-cooled, so the tip of the tip became red hot and the arc became slightly unstable, and the tip melted once. No. Since No. 4 was not water-cooled, the welding tip and the welding nozzle were heated to a high temperature due to the heat generation of the electric resistance and the radiant heat of the welding, and the electric conductivity was deteriorated and the arc became unstable. Also, the welding tip melted three times and welding was interrupted.

[0019]

According to the tip holder for submerged arc welding of the present invention, the welding nozzle and the welding tip are cooled even in the welding of a large current and a large heat input, so that the energization is caused by the heat generation resistance or the radiant heat of the welding. It does not deteriorate and does not dissolve. Therefore, excellent electrical conductivity and wire feedability can be obtained. Furthermore, since it is a split type structure, it is easy to attach and detach.

[Brief description of drawings]

FIG. 1 is an example of a perspective view of a tip holder for submerged arc welding according to an example of the present invention.

FIG. 2 is a cross-sectional view of the tip holder of FIG. 1 mounted on a welding nozzle.

FIG. 3 is a front view in which the chip holder of FIG. 1 is divided.

FIG. 4 is a sectional view taken along the line AA ′ of FIG.

FIG. 5 is a perspective view showing another tip holder for submerged arc welding according to the present invention.

FIG. 6 is a perspective view showing another tip holder for submerged arc welding of the present invention.

FIG. 7 is a cross-sectional view showing a groove shape of a test plate used in an example of the present invention.

[Explanation of symbols]

 1 Welding Nozzle 2 Cooling Pipe 3 Welding Nozzle Tip 4 Water Cooling Plate 5 Tip Holder 6 Welding Tip 7 Projection 8 Groove 9 Projection Structure t Plate Thickness a Route Face θ Groove Angle W Wire

Claims (1)

[Claims] 1. A structure in which a welding tip is concentrically connected to the tip of a welding energizing nozzle, and a split tip holder provided with a cooling member is closely attached to the tip of the nozzle and the outer circumference of the tip. A tip holder for submerged arc welding, which is characterized by