JPS6113902B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an arc welding device that stabilizes the pulsed arc so that the arc does not break.

The first DC power supply A (also referred to as a back ground power supply) maintains a relatively small current arc that does not cause spray transfer between the workpiece and the electrode by itself, and the Pulse arc welding is a method of arc welding in which a second DC power source B (also referred to as a pulse generating power source) that periodically generates a sufficient pulsed current is connected in parallel to the arc as shown in Figure 1. This is called a welding method, and in FIG. 1, 1 and 11 are inductances, 2 is an electrode, 3 is an arc, and 4 is an object to be welded. The function of the inductance 1 in FIG. 1 is to smooth out the current ripples during the conduction of the back ground current _IB , and to maintain a stable pilot arc without arc breakage, etc., even when the arc length fluctuates. Therefore, the inductance 1 is required to have a value greater than a certain value, and if the value is small, arc instability such as arc breakage will occur. The function of the inductance 11 is to obtain an appropriate pulse current, and if this value is too small, the pulse current will become excessive, causing problems such as increased spatter, arc breakage, and uneven weld bead. On the other hand, if it is too large, it will not be possible to obtain the pulse current necessary to transfer the droplets. Therefore, inductance 1 is required to have a sufficiently large value to stabilize the arc when background current is applied, and inductance 11 is required to have an appropriate value. In a conventional pulse arc welding machine (see Figure 1), the flow of the pulse current I _P and the back ground current I _B is as shown in Figure 3 A, as shown in Figure 3 A. The rise is delayed by the large inductance 1, resulting in a drop in arc current as shown at 10 in FIG. 3B.

At this time, there were problems such as arc breakage and increased spatter due to arc instability.

This invention eliminates the drawbacks of the conventional method, and the current is smoothed during the back-ground current application period, preventing arc breakage and arc instability, and making it possible to achieve extremely stable pulse welding in both small and large current ranges. The purpose is to obtain equipment.

Embodiments of the invention will be described based on the drawings.

FIG. 2 shows an apparatus according to an embodiment of the invention.

The same reference numerals as in FIG. 1 indicate the same parts. 5 is the core, 6 is connected to the back ground power supply, and the core 5
The inductance 7 is wound around the inductance, and the inductance 7 is connected to the pulse generation power source. A closed loop is formed in the order of the first DC power supply A, the electrode 2, the arc 3, and the workpiece 4, and on the second DC power supply B side, a closed loop is formed in the order of the inductance 7, the electrode 2, the arc 3, and the workpiece 4. . Both inductances 6 and 7 are magnetically coupled by the core 5 or the like, and when a current flows through the inductances 6 or 7, for example from the electrode 2 in the direction of the workpiece 4, the direction of the magnetic flux formed in the core 5 is as follows: Configure windings 6 and 7 so that they are in the same direction (for example, 8).

Next, the operation of this device will be explained.

During the background current period, a current flows through the inductance 6, thereby forming magnetic velocities in, for example, eight directions, and the core 5 is magnetized. Next, when the pulse current I _P begins to flow through the inductance 7, the core 5 is excited compared to the conventional example shown in Fig. 1, so the pulse current I _P rises and rises as shown in Fig. 4 A. becomes steeper. At this time, the background current I _B decreases and becomes zero when the pulse current I _P reaches its peak value. Next, when the pulse current I _P starts to decrease, the background current I _B starts flowing again, but since the core 5 is sufficiently excited by the pulse current I _P , the inductance 6 at this time is as if its value is It acts as a small inductance, and therefore the rise of the background current is much steeper than that flowing through the conventional inductance 11 shown in FIG. As a result, as shown in Fig. 4 (b), there was no decrease in the arc current as shown in 10 in Fig. 3 (b), and therefore, extremely good pulse arc generation was achieved without arc breakage or arc instability. realizable.

Then, while the background current is flowing thereafter, this inductance 6 acts as a large inductance that does not cause arc instability.

That is, according to this embodiment, the pulse current I _P
The inductance 6 can be formed to set the background current so that the inductance value becomes small during the period when the current flows.When the normal background current flows, the inductance value becomes large, and when the pulse current flows, the inductance becomes small. By forming this, extremely stable pulsed arc welding is possible. The characteristics of the background power source and the pulse generating power source used in this device are not particularly limited, whether they are constant voltage characteristics or drooping characteristics, and any combination is effective. It is also effective, of course, for a so-called integrated pulse power source (the first DC power source A and the second DC power source B are composed of the same transformer) that utilizes unbalanced impedance.

According to the present invention, as described above,
By winding and coupling the inductances of the first DC current and the second DC power source so that the magnetic flux formation direction is the same, (1) In the case of pulsed arc welding with a small arc current (in this case, of course, (2) Even if the background current is narrowed down to a small value, arc breakage or arc instability will not occur due to the rapid recovery of the background current after pulsed current is applied. (3) As explained in the explanation of the operation, the rise of the pulse current itself is extremely steep, so even with a large diameter wire, extremely smooth spray transfer is possible. (4) An extremely stable arc with no arc breakage or arc instability can be obtained from a small current of 20A to a large current of 400A. (5) The bead itself is uniform and smooth, and does not respond to changes in wire protrusion length. It produces extremely excellent effects in pulse welding, such as showing good adaptability to various types of welding.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of a conventional arc welding device, Figure 2 is a circuit diagram of a conventional arc welding device.
The figure is a circuit diagram of an arc welding device showing an embodiment of the present invention, FIG. 3 is a current waveform diagram of the conventional device shown in FIG. 1, and FIG. 4 is a current waveform diagram of the embodiment device shown in FIG. 2. It is a diagram. A...First DC power supply, B...Second DC power supply,
1, 11...Inductance, 2...Electrode, 3...
...Arc, 4...Workpiece, 5...Core, 6...
First DC power supply side inductance, 7... Second DC power supply side inductance, 8... Magnetic flux formation direction, 1
0...Decrease part of arc current.

Claims (1)

[Claims] 1 A first DC power source that maintains a relatively small current arc between the workpiece and the electrode that does not cause spray transfer by itself, and a second DC power source that periodically generates a pulsed current sufficient to cause spray transfer. In the arc welding apparatus, a power source is provided in parallel with the welding arc, and inductances are arranged in the first DC power source in series with the arc load and in the second DC power source in series with the arc load, each of the inductances being arranged in the same core. An arc welding device characterized by winding and coupling so that magnetic flux is formed in the same direction.