JPH0790364B2 - Consumable electrode arc welding method - Google Patents

Description

The present invention relates to a consumable electrode type arm welding method applied to metal consumable electrode type arc welding.

[Prior Art] FIG. 4, which is a conventional example, shows a gas shield arc welding method which is a typical example of a consumable electrode type arm welding method using one welding wire. 01 is a welding power source and 025 is a welding power source. The conduit 018 guides the shielding gas 019 and the welding arc 02
2 and a shield nozzle for protecting the weld metal 023 from the atmosphere, 025a is a guide of a good conductor which has a through hole at its center for guiding the welding wire 010 to the welding portion, and which guides the welding current, and 024 is the welding wire 010. Power and welding wire
A contact tip for guiding 010 to the welding portion, 016 is a coiled wire reel, 017 is a regulator for changing the voltage or current of the welding power source 01, 021 is the object to be welded, 026 is the welding wire 010. The motors 014 and 015 for feeding the welding wire are composed of feeding rollers for the welding wire 010.

As shown in FIG. 4, one contact tip 024 feeds one welding wire 010 to generate a welding arc 022, which is a one-chip one-arc method. When performing high-speed welding, the welding wire is fed. It is necessary to increase the feed rate and perform welding at a high current, that is, at a high current density, with respect to the diameter of the welding wire used, and as a result, the arc force becomes large and undercut beads or irregular beads are likely to occur.

Furthermore, if the welding wire feed rate is increased to increase the amount of deposition, the welding arc becomes unstable and a good welding bead cannot be formed, so the upper limit of the welding speed becomes lower with a single welding arc, for example, fillet welding. At
Welding speed 800 ~ 900mm / mi with 1.2mm welding wire
n is the upper limit.

[Problems to be solved by the invention]

In consumable electrode type arc welding, when trying to increase the welding speed, it is necessary to increase the welding wire feed rate, that is, the welding current, in order to secure the required amount of deposited metal per unit length. However, as the welding current increases, the arc force becomes stronger, and the molten metal immediately below the welding arc is dug deeper and the flow of the molten metal becomes irregular.As a result, undercut beads or irregularities occur in high-speed welding. There are problems such as the formation of beads.

[Means for solving problems]

In order to solve the above problems, the present invention provides a welding wire feeding speed from welding wire feeding holes which are opened concentrically and concentrically on the same circumference in a cross section of a power feeding contact tip attached to a welding torch. This is a welding method in which the pulse is changed and a phase difference is provided in the pulse feeding. That is, in a consumable electrode type arc welding apparatus for feeding and welding a welding wire, a system for feeding a plurality of welding wires and a plurality of the welding wires concentrically on the same circumference in a cross section and concentrically. Through a welding torch that integrates a power feeding contact tip having a feed hole, into a welding arc space, pulse feeding is performed by a system that feeds a plurality of the welding wires, and each pulse feeding is performed. It is intended to provide a consumable electrode type arc welding method characterized in that welding is carried out by providing a phase difference in the feeding of a welding wire.

[Work]

Since the consumable electrode type arc welding method of the present invention is the above-described welding method, the electrodes made of the welding wire are arranged substantially equidistantly and concentrically on the same circumference so that the heat input and the arc force by the welding arc are generated. In parallel arcs with the same power source, the current flowing through the electrodes consisting of each welding wire is approximately proportional to the welding wire feed amount, so that the electromagnetic force acting between the welding arcs of each electrode is reduced. The electrode made of a welding wire is pulse-fed, and the pulse-fed electrode is provided with a phase difference to suppress the spatter that is generated in large quantities by welding, forming undercut beads and irregular beads during high-speed welding. It is possible to prevent it.

〔Example〕

Hereinafter, the present invention will be specifically described based on the embodiments shown in the drawings. FIG. 1 is a perspective view showing a welding state in which a consumable electrode type arc welding apparatus according to an embodiment of the present invention is applied, and FIG. 2 is incorporated in a welding torch of the consumable electrode type arc welding apparatus according to the present embodiment. The contact chip (a) is a perspective view,
FIG. 6B is a sectional view taken along the line DD ′ of FIG. 3A, and FIG. 3 is a waveform diagram example of the motor speed phase control according to the present embodiment.

As an example of the present invention, a method of using a three-pole welding wire arranged on the same circumference was shown, but the present invention is not limited to this, and one welding at the center and three weldings on the concentric circumference, or more The method of arranging the wires is also included in the present invention.

In FIG. 1, reference numeral 1 is a welding power source, 2 is a welding torch, and is composed of the following parts.

Reference numeral 3 is a tube of a good conductor of electricity, to which a tube 18 for guiding a shield gas 19 and a terminal 20 for connecting a cable from the welding power source 1 are attached. Reference numeral 4 is a pipe of an electrically insulating material for attaching the welding torch 2 to a supporting metal fitting of a traveling carriage (not shown), and a pipe 3, a shield nozzle 5 and a pipe 4
And are screwed together. As a result, the shield nozzle 5 is electrically insulated from the positive electrode of the welding power source 1. 6 is a pipe for guiding the welding wire 10 and electrically connecting the terminal 20 and the contact tip 7, and 8 is a nut for connecting the pipe 6 and the tip 7. The nut 8 and the pipe 6 are screwed. I am fit.

The welding torch 2 is a generic term for the objects configured by the above respective parts. Reference numeral 9 denotes a conduit cable through which the welding wire 10 passes when the wire reel 16 wound in a coil shape by the motors 11, 12, 13 and the rollers 14, 15 is fed to the welding torch 2. 17 is the voltage or current regulator of the welding power source 1, 21 is the object to be welded, 22 is the welding arc, 23 is the weld metal, and 24 is the motor 1
The rotation speeds of 1, 12, and 13, that is, the feeding speed controller of the welding wire 10. In FIG. 1, A, B, C are motors 11, 1
A consumable electrode type arc welding apparatus is constructed by showing that the reference numerals 2, 13 and the controller 24 are connected by their respective symbols.

In FIG. 2, inside the welding torch 2, a three-pole welding wire 10 is coaxially guided through a small hole E, and a terminal 20 is attached to the welding wire 10 via an electric conduit 3 attached to the outer periphery.
A contact tip 7 integrally attached by matching the small holes E of the three poles with a tube 6 and a nut that conduct electricity to
A motor in which the welding wire 10 is phase-controlled from each of the small holes E
It also serves as a guide for the welding wire 10 which is fed to the upper surface of the object to be welded 21 by 11, 12, 13 and emits a welding arc 22 for welding.

FIG. 3 shows output signals from the controller 24 to the motors 11, 12, and 13, and Hi and Li (i = 1, 2, 3) are speed levels of the respective motors.

Hi represents high level and Li represents low level. T ₁₁ is motor 1
1 high level period, T ₁₂ is motor 12 high level period,
T ₁₃ is the high level period of the motor 13, and T ₁₁ ≈ T ₁₂ ≈ T ₁₃
Is. Further, T ₁₁ + T ₁₂ + T ₁₃ = T, and T is a pulse period.

Next, the application example will be described in detail. The three welding wires 10 are formed by winding the coiled wire reel 16 to the motors 11, 12,
It passes through the conduit cable 9 by 13 and rollers 14 and 15 and is guided to the welding torch 2, and then reaches the welding arc 22 after passing through the pipe 6 and the contact tip 7. The three welding wires do not have to be of the same type, and the type of welding wire and the diameter of the welding wire are selected according to the welding procedure.

Electric power is supplied from the welding power source 1 to the three welding arcs 22. Since the contact tip 7 shown in FIG. 2 also has three small holes E formed at substantially equal intervals on the same circumference,
The welding arc 22 is generated between the tip of the welding wire 10 and the object to be welded 21 in the same arrangement as the small hole E formed in the contact tip 7.

If the feed rate of the welding wire 10 is the same for each electrode, the welding current flowing through each electrode will be about the same. At this time, since the directions of the currents flowing through the respective electrodes are the same, each welding arc is always subjected to a large force toward the center. This is one of the causes of spatter generation in the parallel welding arc.

As shown in FIG. 3, when the rotational speeds of the motors 11, 12, 13 for feeding the welding wire 10 to each electrode are changed, the welding current flowing to each electrode also changes in the same manner. At this time,
The Hi and Li (i = 1 to 3) levels of each motor are selected so that the average speed is the speed when no pulse is fed. As a result of the above, when the welding current of one electrode is at high level, the other two are at low level, so the electromagnetic force acting on the arcs of each electrode is small on average, resulting in electromagnetic force. Spatter is reduced.

Next, when comparing the case where the same current is applied to the three welding arcs as a single welding arc, the individual welding arcs of the multiple welding arcs (three in the example) are more than the currents of the single welding arc. Because it is small, the melting part is dug down by the arc force,
Also, the action on the molten metal is reduced.

Further, when the electrode arrangement is appropriately selected, the three welding arcs are regarded as a large single welding arc. From this result, a substantial increase in the cross-sectional area of the welding arc column and a decrease in the agitation of the molten metal facilitate the formation of regular weld beads that do not cause undercut even in high speed welding. In this way, when comparing the arc force of a single welding arc and multiple welding arcs at the same current, the multiple welding arc is smaller, and the multiple welding arc forms a softer welding arc than the single welding arc. Therefore, a weld bead that does not cause welding defects in high-speed welding can be obtained.

〔The invention's effect〕

As described above, according to the present invention, defective beads such as irregular beads and undercut beads do not occur even at high speed welding of 1.5 to 2 m / min. Further, since a plurality of welding wires can be fed to each in a flexible conduit cable, the welding torch and welding wire feeding mechanism required for robot welding can be configured in a flexible manner and the welding wire feeding can be performed. By using pulse phase control, spatter generated in parallel welding arcs can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing a welding state in which a consumable electrode type arc welding apparatus according to an embodiment of the present invention is applied, and FIG. 2 is incorporated in a welding torch of the consumable electrode type arc welding apparatus according to the present embodiment. The contact chip (a) is a perspective view and the contact chip (b) is the same.
FIG. 3A is a sectional view taken along the arrow D-D 'in FIG. 3A, FIG. 3 is an example of a motor speed phase control diagram according to this embodiment, and FIG. 4 is a perspective view showing a conventional welding state. 1 ... Welding power source, 2 ... Welding torch, 3 ... Electric conduit, 4
...... Electrical insulation tube, 5 ...... Shield nozzle, 6 ...... Tube, 7
...... Contact tip, 8 ... Nut, 9 ... Conduit cable, 10 ... Welding wire, 11,12,13 ... Motor, 14,15 ... Feeding roller, 16 ... Wire reel, 17 ...
… Current regulator, 18 …… Conduit, 19 …… Shield gas, 20…
… Terminal, 21 …… Welding object, 22 …… Welding arc, 23
…… Welding metal, 24 …… Motor speed controller.

Claims (1)

[Claims] 1. A consumable electrode type arc welding apparatus for feeding and welding a welding wire, comprising: a system for feeding a plurality of welding wires; Through a welding torch that integrates the power feeding contact tip having the welding wire feeding hole, into a welding arc space, while performing pulse feeding in a system that feeds a plurality of the welding wires, the pulse feeding is performed. Is a consumable electrode type arc welding method in which welding is performed by providing a phase difference in the feeding of each welding wire.