JPH0342183A - Method and equipment for multiple electrode welding - Google Patents

Abstract

PURPOSE:To perform welding with high precision by bringing the tips of two wires close to each other while feeding these wires at the same time, concentrating arcs on one point to perform welding at the time of root running, separating the tips of the two wires from each other, directing the arcs to the wall side of a groove to perform welding at the time of welding remaining layers. CONSTITUTION:At the time of root running, respective torches 1a and 1b are rotated and the tips of both wires 3 are brought close to each other so that the feed direction of the wires 3 from contact chips 2 is concentrated on one point. Since the arcs can be concentrated on one point, root running can be performed while feeding the two wires and a back bead can be formed. In addition, at the time of welding the remaining layers, since the rotational positions of both torches 1a and 1b are changed and the feed direction of both wires 3 is turned to the groove wall side, the arcs can be directed to the groove wall and it is prevented that only the central part is built up. By this method, root running with high efficiency can be performed and even a narrow gap where oscillation cannot be carried out can be subjected to welding work with high precision.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a multi-electrode welding method and apparatus used for performing high-efficiency welding from first layer welding to remaining layer welding within a groove using multiple electrodes.

[Prior Art] As schematically shown in FIG. 4, for example, a groove e formed for butt welding a base material C2d is guided through two torches a and b and fed. A so-called consumable electrode type multi-electrode welding device that melts the wire f to fill the groove e has been used in the past. A conventional multi-electrode welding device, as shown in FIG.
The main wire f is fed in parallel to weld. When welding a groove e as shown in Fig. 4 with such a conventional multi-electrode welding device, the two wires f are fed in parallel with the conventional multi-electrode welding device, so that the directions of the arcs are also parallel. Because of this, in the first layer welding, one wire r
An arc is generated from a chisel.The initial layer (6) welding is performed with a spoon, and for residual layer welding, an arc is generated from two wires to perform residual layer welding.

[Problems to be Solved by the Invention] However, when welding the groove e using the conventional multi-electrode welding device described above, two torches a are used.

Since the two wires f are fed in parallel from b, the arc force during residual layer welding is strong and it is possible to work efficiently on joints with a large groove angle, but on the other hand, when welding the first layer, two If two wires f are simultaneously fed to generate an arc, it is expected that an excessively convex bead will be formed in the center.

If the next layer is welded under such conditions, harmful defects such as poor fusion are likely to occur, so initial β welding is performed using only one wire f, but the arc force is weak and There is a problem that makes it difficult to make waves.

Also, during residual layer welding, when working in a narrow gap where it is not possible to oscillate torches a and b from side to side,
Since the method uses a method in which the main wire r is fed in parallel, the arc is always directed downward, making it difficult to ensure stable penetration of the wall side of the groove e, as well as causing poor fusion and undercuts. Cheap.

On the other hand, in a single electrode welding device, in order to perform fillet welding, as shown in FIG.
There is a device in which the wire f can be turned by rotating the torch a at high speed (Japanese Patent Application Laid-open No. 249667/1983). If this single-electrode welding device is used for groove welding as described above, the same result as oscillating the wire "left and right by rotating the torch a" can be obtained, but the feeding direction of the wire "f" can be directed toward the wall. Not only is it unsuitable for welding the remaining layers, but since it is a single electrode, it is difficult to produce back waves when welding the first layer, and
There is a problem that work efficiency is not good when residual layer welding is performed. Furthermore, in the case of this single electrode welding device, during welding work,
Since the wire f rotates at high speed on the molten pool i having the shape shown in Fig. 7, the protrusion length of the wire f constantly changes in each direction, as shown by the dimension j, and the arc becomes unstable. There is a problem. k indicates the height of the bead. Generally, in consumable electrode type welding, when the wire protrusion length changes, the self-holding property of the power supply has the effect of keeping the wire protrusion length constant. However, in the consumable electrode type welding method that rotates at high speed as shown in Fig. 7, the wire f
The self-holding characteristics of the power supply do not follow changes in the protrusion length.

That is, the arc becomes unstable with each rotation cycle, making it impossible to maintain a healthy droplet transfer system, resulting in problems such as an increase in the occurrence of spatter.

Therefore, the present invention provides the following advantages when welding a groove using multiple electrodes.
A multi-electrode welding method and device capable of performing welding with high precision and efficiency by forming a good back wave during initial layer welding and preventing build-up only in the center during residual layer welding. This is what we are trying to provide.

[Means for Solving the Problems] In order to solve the above problems, the present invention, during initial welding, simultaneously feeds two wires and brings their tips close together to concentrate the arc at one point to perform welding ( When welding the remaining layer, separate the tips of the two wires and apply the arc to the groove wall 111.
A multi-electrode welding method and device characterized by performing welding toward.

[Operation] When welding the first layer, the arc can be concentrated at one point by rotating each torch and bringing the tips of both wires close together so that the feeding direction of the wire from the contact tip is concentrated at one point. Therefore, the first layer can be welded while feeding two wires, and a back wave can be formed. Also, when welding the remaining layer, the rotational positions of both torches are changed so that the feeding direction of both wires is directed toward the groove wall, so that the arc can be directed toward the groove wall, and only the central part is welded. There will be no more situations where you will be left with too much meat.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 shows one row 051 of the multi-electro welding device of the present invention, each of which is equipped with a contact tip 2 suitably curved so as to change the feeding direction of the wire 3 at the tip (lower end). Two torches la, Ib are arranged in parallel at a required interval, and their base ends (upper ends) are rotatably supported by the torch holder 4, and both torches la,
As a power transmission device for transmitting rotational force to ib, gears 5.6 are attached to torches 1a and lb, respectively, and an idler gear 7 meshing with gear 6 is provided, and a motor 9 is provided as a drive device for imparting rotational force. torch holder 4
A drive gear 8 installed at the motor 9 and attached to the output shaft of the motor 9.
and the idler gear 7, and the driving force of the motor 9 is transmitted to the idler gear 7 and the power transmission gears 5 and 6 via the drive gear 8, thereby allowing both torches 1a to be connected to each other.

1b is rotated and the tips of both contact tips 2 are moved closer or farther apart, so that the feeding direction of the wire 3, that is, the direction of the arc, is concentrated at one point, or the tip of the contact tip 2 is moved toward the wall side of the groove. To be able to be directed to. Note that the welding power sources for each of the torches la and Ib may be shared or separate.

Using the multi-electrode welding device of the present invention having the above configuration,
For example, when performing welding work on a groove 12 formed by base materials 10 and 11 as shown in FIG. 9 to rotate both torches la and lb to adjust the orientation of the tips of the contact tips 2 in a direction in which they are concentrated at one point, and in this state the rotational positions of both torches la and ib are fixed. In this state, welding current is applied to both torches la and lb while simultaneously feeding the two wires 10. As a result, the two wires 3 pass through the curved contact tip 2 and the torch la,
Since the direction is changed from the axial direction of the lb and is fed in a direction where it is concentrated at one point, it is possible to weld by concentrating the arc generated from both wires 3 at one point, which increases the force of the arc. be able to. Therefore, by moving the entire welding device so that this concentrated arc follows the abutting surfaces of the base metals 10 and 11, the abutting surfaces of the base metals 1011 are sufficiently penetrated, and the initial layer welding is performed. It is possible to form a back wave in the process, and it is possible to perform first layer welding with high efficiency.

When welding the middle layer after the first layer welding is completed,
As shown in FIG. 3, the torches la and ib are rotated by the motor 9 so that the tips of the contact tips 2 are separated from each other and are directed toward the wall of the groove 12. As a result, the feeding direction of the two wires 3 is directed to the wall side of the groove 13, so if welding work is performed in this state, the wall side will be sufficiently heated and melted, so that the compatibility of the molten metal will be reduced. This is a second improvement, and it is no longer possible to overfill only the central portion as in the past. Thereafter, by sequentially moving the build-up position upward in the same state, the groove 12 can be efficiently welded.

In this way, in the present invention, during initial welding, the feeding direction of the two wires 3 is adjusted by rotating the contact tip 2 so as to concentrate the arc at one point, and during residual layer welding, the direction of feeding of the two wires 3 is adjusted. Since the contact tip 2 is rotated so as to face the wall and the wire feeding direction is changed, even in narrow gaps where oscillation cannot be performed, welding can be done in the same condition as oscillation. can.

In addition, as shown in FIG. 2, the width of the groove 12 increases as it goes upward, and if it is in a state where it can be oscillated,
that oscillation operations may be used together;
In addition, during the remaining layer welding work, the arc may be concentrated at one point to perform build-up work at the center if necessary, and furthermore, in the embodiment, the feeding direction of the wire 3 is changed. In addition, only the hole through which the wire 3 is passed may be curved or inclined, and various changes may be made without departing from the gist of the invention. Of course.

[Effects of the Invention] As described above, according to the present invention, when welding a groove,
The two wires are fed at the same time, and the direction of feed of the two wires is changed so that the arc is concentrated at one point when welding the first layer, and the arc is directed toward the wall when welding the remaining layer. Even when welding layers, it is possible to always form a stable underwave, allowing for highly efficient welding of the first layer, and when welding remaining layers, it is possible to build up the weld toward the wall side, so that only the center part is built up. This has the excellent effect of eliminating welding, making it possible to perform welding work with high accuracy even in narrow gaps where oscillation cannot be performed.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the multi-electrode welding device of the present invention, FIGS. 2 and 3 are schematic diagrams showing a state in which a groove is welded by the multi-electrode welding device of the present invention, Fig. 4 is a diagram showing an overview of groove welding using a conventional multi-electrode welding device, Fig. 5 is a schematic diagram of a conventional multi-electrode welding device, and Fig. 6 is an example of a conventional single-electrode welding device. FIG. 7 is a schematic diagram showing a state in which welding is performed using the single electrode welding apparatus shown in FIG. 6. la, lb...torch, 2...contact tip,
3...Wire, 4...Torch holder, 5,6...
・Gear (power transmission device), 7...Idler gear (power transmission device), 8...Drive gear, 9...'E-ta (drive device), 10.11...Base material, 12.・Bevel.

Claims (2)

[Claims] (1) During initial welding, welding is performed by feeding two wires simultaneously and bringing their tips close together to concentrate the arc on one point. During residual layer welding, the tips of the two wires are separated and the arc is opened. A multi-electrode welding method characterized by welding toward the wall side. (2) Two torches each having a contact tip at the tip configured to change the feeding direction of the wire are arranged in parallel and rotatably supported by a torch holder,
Each electrode welding device is characterized in that the torch holder is equipped with a power transmission device that transmits rotational force to both torches, and a drive device that provides rotational force.