JPH05293664A - Multi-electrode gas shield arc welding method - Google Patents

Abstract

(57) [Abstract] [Purpose] Multi-electrode 1 for overlay welding of high alloys
A wide range of beads can be formed by the pool-type gas shield arc welding method, and a decrease in the amount of alloy due to dilution of the overlay layer can be suppressed. [Structure] It consists of two or more torch bodies and a shield cup, and the shield cup has an opening on the side of the work. The torch body is fitted to the inner ceiling opposite to the work, along with through holes for shielding gas discharge. A torch body holding block made of an insulating material is provided above the ceramic plate with a through hole for matching, and the torch body is insulated from each other by gas shield arc welding, and each torch body has its own AC welding power source. Or use an inverter DC welding power source.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal arc welding method, and more particularly, by multi-electrode gas shielded arc welding, particularly in welding of high alloy steel, reduction of alloy amount due to dilution of weld metal can be suppressed as much as possible. Further, the present invention relates to a method of performing high quality and high efficiency welding capable of increasing the amount of deposition per pass in the welding of low alloy steel.

[0002]

2. Description of the Related Art Conventionally, as a gas shielded arc welding method for relatively high-quality metal, a consumable electrode and an inert gas M
IG welding is widely used. Attempts have also been made to perform high-efficiency welding by twinning the MIG arc (Japanese Patent Laid-Open No. 64-87072). Further, in overlay welding of high alloy layers or butt welding of high alloy clad steels, a welding method that reduces the dilution ratio of the ordinary steel base material to suppress the decrease in the alloy amount of the high alloy buffer layer or clad layer weld metal as much as possible. T is a necessary and conventional technology for that.
The IG method, the PLASMA method, and those described in Japanese Patent Application Laid-Open No. 2-6058 by the present inventors.

However, these conventional techniques have limitations in improving efficiency and quality. That is, the former had a problem of workability in which it was difficult to perform welding for a long time because the nozzle in the gas shield box was clogged with spatter. In the latter case, if the welding speed is increased or the bead width is increased, it is necessary to increase the oscillating speed, so large spatters are generated and the spatter adheres to the end of the weld bead and grinds the surface of the weld. There was a problem that it took time to finish.

[0004]

DISCLOSURE OF THE INVENTION The present invention can suppress the decrease in the alloy amount due to the dilution of the weld metal as much as possible particularly in the welding of high alloy steel, and increase the deposition amount per pass in the welding of low alloy steel. High-quality and high-efficiency welding that can be done, and high-quality and high-efficiency welding that can increase the amount of deposition per pass in welding low-alloy steel, and a gas shield box with a small amount of shielding gas An object of the present invention is to provide a multi-electrode gas shield arc welding method in which the nozzle inside the (shield cup) is less likely to be clogged with spatter.

[0005]

Means for Solving the Problems As a result of earnest studies on specific means for solving the above-mentioned problems, the present inventors have developed a new torch for multi-electrode gas shielded arc welding consisting of a torch body and a shield cup. The present invention has been completed on the finding that the above-mentioned object can be achieved by the welding method developed in.

That is, the gist of the present invention is to use a multi-electrode gas shielded arc welding torch comprising two or more torch bodies each having a cooling body passage therein and a shield cup in the multi-electrode gas shielded arc welding method. ,
The shield cup has a plurality of through-holes for discharging shield gas perpendicularly to the plate surface and two through-holes for fitting the torch body on the inner ceiling opposite to the work-side opening.
A detachable ceramics plate provided at least one piece and an airtight torch holding block made of an insulating material are provided above the ceiling part, and the shield gas is discharged downward from the through hole of the ceramics plate to the tip of the torch body. The multi-electrode gas shielded arc welding method is characterized in that the arc atmosphere is protected from the atmosphere.

Also, preferably, the two or more water-cooled torch electrodes have contact tip tilted pedestals accumulated at their respective tips to keep the distance between the tips of the consumable electrode wires from 1 to 5.
0 mm variable type, and the two or more water-cooled torch electrodes can slide up and down through the through holes of the ceramic plate, and the tip of the contact tip is 1 mm from the bottom of the shield cup 20 mm.
It is fixed by the torch holding block within the range below 00 mm, and a shield gas is discharged from the lower end of the shield cup opening wall to form a double shield type, and further a multi-electrode composed of the torch body and the shield cup. A multi-electrode gas shield arc welding method using a torch for gas shield arc welding, which is characterized in that an AC welding power source or an inverter DC welding power source is used.

[0008]

The present invention will be described in detail below. In FIG. 1, 1 is a gas shield torch for multi-electrode arc welding used in the present invention, and the main parts are a torch body 2 and a shield cup 3. The torch body and the shield cup are made of a copper alloy and have a cooling fluid passage 4 inside, and the shield cup 3 has an opening 5 on the side of a work 11 (material to be welded), and an inner ceiling portion opposite to the work. As shown in FIG. 2, a plurality of through holes 10 for emitting shield gas and two or more through holes 13 for fitting the torch body are provided perpendicularly to the plate surface, and the removable ceramic plate 6 is insulated above the ceiling. A torch holding block 7 made of a material and having an airtightness is provided, and a shield gas 8 is discharged downward from the through hole 10 of the ceramic plate 6 and a laminar flow shield gas is applied at the tip of the torch body at the shield cup opening. The atmosphere of the arc 9 and the molten pool as well as the hot parts of the weld bead 12 can be protected from the atmosphere.

The periphery of the ceramic plate 6 and the torch holding block 7 made of an insulating material are in close contact with the inner wall of the shield cup 3, and the outer walls of the torch body are in close contact with two or more through holes 10 in the central portion. Since the temperature is kept below about 100 ° C even after performing gas shield arc welding for a long time,
Each of the two or more torch bodies can be electrically well insulated.

As shown in FIG. 3, an independent welding power source 16, wire feeder 17 and welding condition controller 20 are used for these torch bodies 2, and each torch body insulated between the torches is welded. The current and arc voltage can be set independently, and a very stable twin arc (in the case of two torch bodies) can be obtained. Further, since the temperature of the ceramic plate does not rise, the shield gas discharge hole 10 of the ceramic plate does not become clogged with spatter, so that it is possible to carry out multi-electrode gas shield arc welding for a long time and to shield gas. The flow rate can be reduced.

Next, the two or more torch main bodies can be provided with contact tip inclined pedestals 14 accumulated at their respective tips, and their inclination angles or wire extensions (distance from the tip of the contact tip to the arc generation point). The inter-electrode distance 18 (distance between the tip of the consumable electrode wire or the arc generation point) can be changed by changing

The cross section of the torch body, which is in contact with the through hole of the ceramic plate and the torch holding block of the insulating material, is circular so that it can rotate at any angle and can move in the vertical direction as well. On the other hand, the height of the tip of the contact tip fixed to the torch body with respect to the lower end of the shield cup can be freely changed and fixed with a fixing screw (not shown) of the torch holding block.

The reason why the distance between the electrodes of the torch body is limited to the range of 1 to 50 mm is as follows. The lower limit of 1 mm is because the consumable electrode wire used in the present invention is a so-called small-diameter wire having a diameter of 1 to 2 mm, and the distance between the two wires having a diameter of 1 mm is 1 mm when the wires are closest to each other. 50 mm
Is the maximum distance between two 2mm diameter wires and high current welding 1
This is because it is the limit of pooling.

The height of the tip of the contact tip fixed to the torch body relative to the lower end of the shield cup is set to 20
The reason for limiting to 100 mm to 100 mm below is that the tip of the contact tip should be retracted from the bottom of the shield cup when welding the surface layer bead at the top of the groove, but if it is retracted more than 20 mm, the wire extension becomes too long and the arc becomes unstable. Therefore, the upper limit is set to 20 mm, and the groove depth capable of gas shielding by the shield torch of the present invention is about 100 mm, so the lower limit is limited to 100 mm.

Further, as shown in FIG. 1, a double shield type torch can be obtained by discharging the shield gas from the outer nozzle shield gas discharge hole 15 at the lower end of the shield cup opening wall.

The reason why the welding power source in which the torch for multi-electrode gas shielded arc welding composed of the torch body and the shield cup is combined is limited to the AC welding power source or the inverter DC welding power source is the other power sources, that is, the more general power sources. This is because, when performing twin arc welding with a thyristor DC welding power source, it is necessary to set the distance between the electrodes to 35 mm or more in order to prevent arc breakage due to arc interference. In practice, it is effective to perform twin arc welding with a gap between the electrodes of 5 to 20 mm, because it is necessary to use an AC welding power source or an inverter DC welding power source in which the adverse effects of arc interference can be almost ignored. ..

[0017]

EXAMPLE A gas shield torch for multi-electrode arc welding having the structure shown in FIG.
After welding for a minute, the welding performance was compared with the conventional example. The results are shown in Table 2.

[0018]

[Table 1]

[0019]

[Table 2]

[0020]

As described above, according to the welding method of the present invention,
High-quality and high-efficiency multi-electrode gas shield arc welding can be performed, a wide range of beads can be formed, and reduction of the alloy amount due to dilution of the build-up layer can be suppressed.

[Brief description of drawings]

FIG. 1 is a schematic view of a cross section of a gas shield torch for multi-electrode arc welding according to the present invention.

FIG. 2 is a schematic view showing the shape of a ceramic plate used in the torch of the present invention.

FIG. 3 is a schematic view showing the constitution of the welding method of the present invention.

[Explanation of symbols]

 1 Gas Shield Torch of the Present Invention 2 Torch Main Body 3 Shield Cup 4 Cooling Fluid Passage 5 Shield Cup Opening 6 Ceramic Plate 7 Torch Holding Block 8 Shield Gas 9 Arc 10 Inner Nozzle Shield Gas Release Port 11 Workpiece (Workpiece) 12 Weld bead cross section 13 Torch body through hole 14 Contact tip inclined pedestal 15 Outer nozzle shield gas discharge port 16 Welding power source 17 Wire feeding device 18 Electrode distance 19 Consumable electrode wire 20 Welding condition control device

Claims (5)

[Claims] 1. In a multi-electrode gas shielded arc welding method, a multi-electrode gas shielded arc welding torch consisting of two or more torch bodies each having a cooling medium passage therein and a shield cup is used, and the shield cup is A detachable ceramics plate provided with two or more through-holes for emitting shield gas perpendicularly to the plate surface and two or more through-holes for fitting the torch body on the inner ceiling opposite to the work-side opening. An airtight torch holding block made of an insulating material is provided above the ceiling part, and shield gas is emitted downward from the through hole of the ceramic plate to protect the arc atmosphere at the tip of the torch body from the atmosphere. Characteristic multi-electrode gas shield arc welding method. 2. A contact tip tilted pedestal is integrated at each tip of two or more water-cooled torch electrodes, and the distance between the tips of consumable electrode wires is variable within a range of 1 to 50 mm. The multi-electrode gas shield arc welding method according to claim 1. 3. Two or more water-cooled torch electrodes are vertically slidable in the through holes of the ceramic plate, and the tip of the contact tip is fixed by the torch holding block within a range of 20 mm above and 100 mm below the lower end of the shield cup. The multi-electrode gas shielded arc welding method according to claim 1 or 2. 4. The multi-electrode gas shield arc welding method according to claim 1, wherein the shield gas is discharged from the lower end of the shield cup opening wall to form a double shield type. .. 5. A multi-electrode gas shield arc welding method using a multi-electrode gas shield arc welding torch comprising two or more torch bodies and a shield cup, wherein an AC welding power source or an inverter DC welding power source is used. The multi-electrode gas shielded arc welding method according to any one of claims 1 to 4.