JPS6012150B2 - Welding method and welding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a welding method and welding apparatus for synchronizing TIG welding using a non-consumable electrode and MIG welding using a consumable electrode on the same workpiece. .

Conventionally, DC TIG welding and DC pulsed T welding using non-consumable electrodes are different from other welding methods, including MIG welding using consumable electrodes, because wire feeding is independent of the arc state. Although it has the characteristic of being able to control
Melting efficiency (power efficiency) is low at 30-50%, and welding speed is slow.

Therefore, the TIC welding method is only used for thin plate welding and welding of specific metals, and it is not applicable to thick plate welding or automatic welding, which is considered optimal from the viewpoint of wire independent control. Currently, there are many deficiencies. This invention takes into consideration the above-mentioned problems, and makes T.
In IG welding, the arc from the non-consumable electrode and the arc from the feeding wire can be synchronized by supplying power to the welding wire that is fed into the arc that occurs between the non-consumable electrode and the workpiece. It generates a pulse arc,
This invention aims to improve welding speed by increasing melting efficiency. Next, this invention will be explained in detail with reference to drawings showing embodiments thereof.

First, FIG. 1, which shows a conventional pulse TIC welding apparatus, will be described.

In the figure, 1 is a DC power source composed of a three-phase full-wave rectifier circuit and a smoothing circuit, 2 is a non-consumable electrode made of tungsten or thorium-containing tungsten, 3 is the object to be welded, 4 is a welding feed wire, and 5 6 is a feeding roller for feeding wire 4;
is a switch circuit made of a semiconductor element, etc., and 7 is a current limiting element made of a resistor, etc. The switch circuit and current limiting element 7 are connected in series to the connection circuit between the DC power source 1 and the welding gap. The output is switched by the switch circuit 6, the value of the current limited by the current limiting element 7 is determined, and this constant current pulse current is supplied to the welding gap. The switch circuit 6 is switched according to the pulse width and period set by the pulse oscillation circuit 8 and drive circuit 9. The welding pulse current waveform resulting from this switching is shown in FIG. 2. 4 and 5 illustrate the welding apparatus and operating principle for carrying out this welding method.

As mentioned above, the TIC welding method has poor power efficiency and slow welding speed, so power is also supplied to the feed wire and TIG-MIG
When the simultaneous welding method is used, the welding speed is significantly improved.

However, this method is difficult to apply to low current welding such as thin plate welding using DC TIG and DC MIG, and short arcs may cause insufficient penetration or instability of the arc. Therefore, "This invention supplies constant current pulsed power to the non-consumable electrode, and also supplies constant voltage pulsed power to the feeding wire, and welds them in synchronization with each other as shown in Fig. 3. This is a pulse M to -T welding method.

In addition, Fig. 3 shows the welding gap current waveform, the shaded part is the current flowing through the feed wire by the constant voltage power source, and the white part is the current flowing through the non-consumable electrode by the constant current power source. be. Therefore, the welding method of the present invention not only exhibits a much faster welding speed than the conventional TIG welding method, but also achieves sufficient penetration even in low current welding such as thin plate welding, and prevents the generation of spray arcs. Stable welding can be performed. Further, since the welding is pulse welding, the melting efficiency is increased and the electromagnetic pinching force is significantly increased. As a result, magnetic blowing or arc interference can be prevented and the arc can be concentrated.
It can also be applied to thick plate welding, and has a wide range of uses as an automatic welding power source. Next, a welding device for carrying out the present invention will be explained.

As shown in FIG. 4, the device includes first and second DC power supplies 10 and 11. non-consumable electrode 1 through a first backflow blocking circuit 12 that blocks
3, and the other output terminal is connected to a transistor or SC
The welding gun is connected to the object to be welded 16 via a first switch circuit 4 made of a semiconductor such as R and a first current limiting element 15 made of a resistor or the like.

Further, one output terminal of the second DC power supply 18 is connected to the feed wire 18 via a second reverse current blocking circuit 17 that blocks inflow from the first DC power supply 10, and the other output terminal is , connected to the object to be welded 16 and between both output terminals,
A second switch circuit 89 using a semiconductor and a second switch circuit 89 using a resistor.
A short circuit configured by connecting current limiting elements 20 in series is connected. Here, "the backflow prevention circuits 12, 17
has the function of blocking the flow of current from each power source 1 and 0 and keeping the switching waveform unipolar when pulses are generated.

That is, when the feed wire 8 and the non-consumable electrode blade 3 come into contact due to a problem with the feeding mechanism of the feed wire 18, the current flow between the DC power sources 1 and 10 is prevented by the backflow prevention circuits 12 and 17. and furthermore, “
When pulses are generated due to switching, the pulse waveform is disturbed due to the inductance of the circuit, etc., and especially when the pulse is turned off, AC vibration occurs.
However, unipolarity is ensured by the backflow blocking circuits 2 and 1TI. Each of the switch circuits 14 and 19 switches according to the pulse width t and period T set by the pulse oscillation circuit 28, drive circuit 22, and sign inversion circuit 23.

The output signal Vp of the drive circuit 22 is directly input to the first switch circuit 14 , and the inverted signal Vj inverted by the sign inversion circuit 23 is input to the second switch circuit 19 . It goes without saying that even if the two are replaced, the operating principle remains the same. The feeding wire 18 is fed by the feeding roller 24.The operating principle is as shown in FIG. Inverted signal Vi of circuit 23
, and c is the switch operation O of the first switch circuit 14
d indicates ON-OFF of the switch operation of the second switch circuit 19.Here, when the first switch circuit 14 is ON, the non-consumable electrode 13
A constant current arc is generated in the welding gap between the wire and the workpiece 16, and a constant voltage arc is generated between the feed wire 18 and the workpiece 96 when the second switch circuit 19 is OFF. e and f indicate the respective current waveforms, and g is the welding gap current waveform obtained by combining both. In the above embodiment, the non-consumable electrode 13 and the consumable electrode feeding wire 18 have the same polarity, but it is also possible to reverse the polarity.

That is, the non-consumable electrode 13 has a positive polarity due to electrode consumption, but the consumable electrode may need to have a reverse polarity depending on the machine to be welded. As described above, according to the welding method of the present invention and the welding device for carrying out the same,
In addition to providing highly efficient pulse heat input, it can significantly improve the melting speed of the feeding wire and the workpiece, and can be applied to thick plate welding, as well as pulse welding and feeding to obtain sufficient penetration. Because the wire can be controlled independently, it provides a wide range of applications for all-position welding and automatic welding.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a TIG welding device, Fig. 2 is a pulse current waveform diagram of Fig. 1, Fig. 3 and the following drawings show embodiments of the present invention, and Fig. 3 is a welding current waveform diagram, Figure 4 is a block diagram of the welding device, and Figure 5 is a diagram of its operating principle, where a is the output signal of the drive circuit, b is the inverted signal of the sign inversion circuit, and c and d are the signals of the first and second switch circuits, respectively. In the operation diagram, e and f are current waveform diagrams from the first and second DC power sources, respectively, and g is a welding gap current waveform diagram combining e and f. 10,11...DC power supply, 12,17...
Backflow blocking circuit, 13... Non-consumable electrode, 14, 19...
・...Switch circuit, 15, 20... Current limiting element,
16... Work to be welded, 18... Feeding wire 21... Pulse oscillation circuit, 22...
...Drive circuit, 23... Sign inversion circuit. Mai〆zu fin Z diagram ※J zuzuzuzu blind

Claims (1)

[Scope of Claims] 1 Welding is performed by synchronizing pulsed TIG welding using a non-consumable electrode using DC constant current power and pulsed MIG welding using a consumable electrode using DC constant voltage power. Characteristic welding method. 2. A first DC power source that generates a welding arc between the non-consumable electrode and the workpiece, a first current limiting element connected in series to a connection circuit between the first DC power source and the welding gap, and a a second DC power source for generating a welding arc between a consumable electrode and the workpiece, and a second DC power source and a welding gear. A device comprising a second current-limiting element and a second switch circuit connected in parallel to a connection circuit and a second backflow prevention circuit connected in series, and the first and second switch circuits. A welding device comprising a pulse oscillation circuit that alternately switches and drives the welding device, a drive circuit, and a sign inversion circuit.