JPS59179274A - Method and device for welding using hot wire - Google Patents

Abstract

PURPOSE:To decrease generation of an arc in a hot wire and to improve reliability in welding by performing welding at the no-load charge between a base metal and the hot wire which is decreased with respect to the no-load voltage between the base metal and a torch. CONSTITUTION:The output from a transformer 8 is rectified and smoothed to a no-load voltage 70V, the cathode of which is connected via switching transistors 12, 11 to a torch 4 and the chip 5 of a hot wire 6 and the anode to a base metal 7, respectively. TIG current is then made variable by a current control potentiometer 26; on the other hand, the no-load voltage on a hot wire side is set at about <=70V, for example, about 23V by the regulation of a voltage setting potentiometer 25, and the current is made variable by a current control potentiometer 24. The device is further so constituted that pulses are alternately generated from the two output terminals by a pulse oscillator 27. The generation of the arc at the hot wire is thus decreased and the reliability in welding is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a welding method using a hot wire and an apparatus therefor.

[Prior art]

For example, in the hot wire switching welding method, current is alternately applied between the TIG electrode and the base metal and between the hot wire and the base metal in order to prevent arc interference between the TIG electrode and the hot wire. A conventional device for supplying information is constructed as shown in FIG.

In the figure, there is a DC welding power source 1, the cathode of which is connected via a switching transistor 2 to a chip 5 supporting a hot wire 6. Similarly, the cathode is connected to a TIG electrode 4 via a switching transistor 3. Furthermore, the anode of the DC welding power source 1 is connected to the base material 7 to be welded. The switching transistors 2 and 3 are controlled to turn on and off alternately so that J? 9.For this reason, base material 7.TIG
What is the TIG current that flows through the transistors 1 and 4 and the switching transistor 3 as shown in Figure 2 (a)? Danger, again
Base material 7, hot wire 6, switching transistor 2
The hot wire current flowing throughout flows as shown in FIG. 2(b). In addition, in this welding, taking into account that welding in all positions or 6-way welding with Uranami control, the hot wire 6 is not fed to the tip 5 in order to prevent the I@ deposited metal from dripping. 2 as shown in Figure 2 (C).
It is carried out according to purpose.

However, in order to maintain stable arc generation in TIG, conventional devices are designed with no load and a voltage (open circuit voltage) of 70 to 80 cm, taking into consideration the effects of radiation on the human body.
'A < However, the hot wire 6 is shown in Fig. 3(a).
As shown in Fig. 3(b) K
If they are separated as shown, an arc will often occur between the base material 7 and the hot wire 6. For this reason, as shown in FIG. 3(C), the chip 5 was damaged by fire and vines were also generated, making welding impossible.

[Purpose of the invention]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a welding method using a hot wire and an apparatus therefor, which reduces arc generation in the hot wire and thereby improves welding reliability.

[Summary of the invention]

In order to achieve this further object, the present invention arranges a torch and a hot wire on a base material, and supplies power between the base material and the torch and between the base material and the hot wire to perform welding. In the welding method using a hot wire, the no-load voltage between the base material and the hot wire is made smaller than the no-load voltage between the base material and the torch.

In addition, the devices used in carrying out such a method include a power supply device that supplies power between the base material and the torch, and a power supply device that supplies power between the base material and the base material via an I voltage adjustment mechanism. a hot wire to which power is supplied; a voltage detector that detects a voltage between the hot wire and the base material; 71
[Pressure arbitrary setting section and this? an amplifier that compares the output of the voltage arbitrary setting section with the output of the voltage detector and uses the output to vary the output voltage of the voltage adjustment mechanism to a value smaller than the no-load voltage between the base material and the torch; It is something to be prepared for.

For example, in a conventional hot wire cutting device that supplies AC current between the TIG electrode and the base metal and between the hot wire and the base metal, when the hot wire is short-circuited and pulled up from the base metal, the base metal and the hot The generation and persistence of arcs between wires was investigated. In this case, the occurrence and continuation of the arc means that the arc discharge has an apparent appearance of 0.5S1
30. switching frequency 100)
FIG. 4 shows a graph in which the pulse peak current is plotted on the horizontal axis and the /<Rusbeak voltage is plotted on the vertical axis when IZ is used.

According to this figure, it can be seen that the arc radiation limit no-load torque decreases as the current increases, and becomes about 23V when the current decreases to 300A or less.

As a result, by making the no-load voltage between the base metal and the hot wire smaller than that between the base metal and the torch, it is possible to reduce arcs occurring in the hot wire more than in the past.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail using Examples.

FIG. 5 is a block diagram showing an embodiment of an apparatus to which the welding method using hot wire according to the present invention is applied. In the figure, there is a transformer 8, and the output of the transformer 8 is rectified by a diode 9 and smoothed by a capacitor 10. The voltage after smoothing, that is, the no-load voltage, is 70V, and the switching transistor 12, whose cathode is connected to the TiG electrode 4 via the switching transistor 12, is turned on when a signal is applied to its base via LA. It looks like this,
Further, a resistor 28 is connected between the emitter and the collector to stabilize the arc of TI(). Further, the smoothed side cathode is connected to the chip 5 supporting the hot wire 6 via the switching transistor 11.

The switching transistor 11 is turned on when a signal is supplied to its base, and a series body of a resistor 29 and a switch 30 is connected between the emitter and the collector, and when the switch 30 is switched, the i 'I
The G electrode 4 can be replaced with an M or IQ electrode. Further, the anode on the side smoothed by the capacitor 10 is connected to the base I7 to be welded. on the other hand,
TIG' dual flow control potentiometer 26, the output of which is input to one end of the input terminal of the amplifier 19 via the switch 23. The output from the current detector 14 provided on the collector side of the switching transistor 12, that is, on the TIG' electrode 4 side, is input to the other end of the input terminal of the amplifier 190.

As a result, the amplifier 19 amplifies the difference voltage between the signal from the TIG current r>IL control potentiometer 26 and the signal from the I[j current detector 14, inputs the output to the base of the switching transistor 12, and inputs the output to the base of the switching transistor 12. The switching transistor 12 is controlled. In addition, there is a true wire voltage setting potentiometer 25, and if and, the setting potentiometer 25 is the T
I G 'tj'z4≧No-load voltage 7 between trap 4 and base material 7
It is possible to change the value by 17J to a value below 0V. The output of the voltage setting potentiometer 25 is inputted to one end of the input terminal of the amplifier 190 via the switch 22, and the output from the voltage detector 15 provided between the base material 7 and the chip 5 is inputted to the other end. It has become. As a result, the amplifier 17 amplifies the difference voltage between the signal from the heavy pressure control potentiometer 25 and the voltage detector 15, and outputs the amplified signal. This output is further input to one input terminal of an amplifier 18. There is also a hot wire current control potentiometer 24 that can be controlled within the voltage range set by the hot wire voltage setting potentiometer 25.
The signal is input to one terminal of the amplifier 16 via the switch 21. The output from the current detector 13 provided on the chip 6 side is input to the capacity terminal of the amplifier 16.

As a result, the front iI2 amplifier 16 is IIJ, flow:! ii from control potentiometer 24 and current detector 13
Amplifies the voltage difference between the signal from the 70" wide output (
No. 6 is input to the other input terminal of the amplifier 18. This amplifier 18 amplifies and outputs the pressure difference rJi between the outputs of the amplifiers 17 and 1G, and inputs the pressure to the base of the digital transformer 11. .Furthermore, there is a pulse oscillation circuit 27, and this pulse oscillation circuit 27
is constructed so that a pulse is generated from both output terminals, and the front delta switch 23 is repeatedly turned on and off by a pulse from one of the output terminals. Further, the switches 22 and 21 are repeatedly turned on and off by a pulse from the other output terminal.

In this way, in the pot wire switching welding device which has been formed with )R, the base metal 7 and 'f' IQ? jjlC
The no-load voltage of A41t-t can be set to 70V at 17^4), and the TIG current can be varied by the TIG current control potentiometer 26.In addition, the TIG current can be varied by the TIG current control potentiometer 26. No load F for 6
b. The voltage can be arbitrarily set below 70V by adjusting the voltage H constant potentiometer 25, and the hot wire current can be varied by the hot wire current control potentiometer 24.

Using this hot wire switching welding equipment, except when welding a base material with a thickness of 10 mm, the bevel angle of the base material is 25°.
, root gap 1, dissolution rate gold 400mm/ari
a, TIG average current 20OA, hot wire average current -1250A, wire feeding speed 2.5m/j"I
When the continuous wire feeding cycle was set to 2l-IZ and the hot wire no-load voltage was set to 23V, arcing from the hot wire was hardly observed, and therefore no chip burnout or slat ivy occurred. There wasn't. In addition,
The relationship between TIG current and hot wire current in this case is shown in FIG.

In the above embodiment, a hot wire switching welding device that alternately supplies current between the TIG electrode and the base metal and between the hot wire and the base metal is described. It goes without saying that the present invention can also be applied to devices that supply '1 sources between the phase and the torch, and between the base material and the hot wire.

Further, in the above-described embodiment, a TIG electrode was used as the torch, but a MIG electrode would have the same effect.

Further, in the above-described embodiment, a switching element made of a bipolar transistor was used to control the welding current, but it may also be replaced with another half-2.9 element made of an FET, for example. Although it is controlled in an analog manner, a switch blowfish regulator or the like may also be used.

〔Effect of the invention〕

As described above, according to the welding method using a hot wire and its apparatus according to the present invention, the generation of arc in the hot wire can be reduced, thereby improving the reliability of bath welding.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an example of a conventional hot wire switching welding device, FIGS. 2(a), (b), and (C) are timing charts showing the operation in the circuit diagram, and FIG. ), (b), and (C) are explanatory diagrams showing the drawbacks of the conventional device, Fig. 4 is an experimental graph that led to the idea of the present invention, and Fig. 5 is a welding method using a hot wire according to the present invention. FIG. 6 is a timing chart showing the operation of the device shown in FIG. 5. 4...TIG electrode, 6...hot wire, 7...
Base material, 8...trans, lO...ko/ten-! I+
-111,12... switching transistor, 15
...71 pressure detector, 16-18... amplifier, 24 river hot wire current control potentiometer, 25... hot wire voltage setting potentiometer, 26...T
I () 'Ni flow control both the first mouth l! Fig. 12 Fig. 40 1 Solsu Tori 4L glue Fig. S Fig. 29 Fig. 6 Time

Claims (1)

[Claims] 1. Arranging a torch and a hot wire on a base material,
In a welding method using a hot wire in which power is supplied between the base metal and the torch and between the base metal and the hot wire to perform welding, the base metal and the hot wire are A welding method using a hot wire characterized by reducing the no-load voltage between the hot wires. 2. A power supply device that supplies power between the base material and the torch, and a voltage adjustment mechanism from this power supply device to the base material.
A hot wire to which pressure is supplied, a voltage detector that detects the pressure between the hot wire and the base metal, a voltage arbitrary setting section, an output of the r:λ pressure arbitrary setting section, and the voltage detection. and an amplifier that compares the output of the voltage regulator and adjusts the output voltage of the voltage adjustment mechanism to a value smaller than the no-load voltage between the base material and the torch according to the output. Welding equipment.