JPH03207578A - Hot wire tig welding equipment - Google Patents

Abstract

PURPOSE:To furnish the hot wire TIG welding equipment with high reliability by connecting one end of a capacitor to one end of an AC power source for heating a wire, connecting an electrode for heating to the other end of the capacitor and connecting the other end of the AC power source to base metals. CONSTITUTION:A power source 1 for welding is connected to a nonconsumable electrode 2 and the base metals 3. Filler metal 5 is supplied by a motor 7 for feeding the wire and feeding rollers 6. The electrode 8 for heating is provided in the vicinity of the tip of the filler metal 5. The AC power source 9 for heating the wire and the capacitor 12 are connected to the electrode 8 for heating and the base metals 3. The one end of the capacitor 12 is connected to the one end of the AC power source 9 for heating the wire. The electrode 8 for heating is connected to the other end of the capacitor 12. The other end of the AC power source 9 is connected to the base metals 3. By this method, a breakdown such as burning of a transformer in the power source for heating can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a hot wire type arc welding method that performs arc welding while supplying a current to a welding part and a filler metal (hereinafter referred to as a wire) that has been preheated by resistance heating. This relates to TIG welding equipment.

Conventional technology The TTG welding method, which performs welding by generating an arc between a non-consumable electrode such as a tungsten electrode rod and the base metal in an inert gas atmosphere, has the advantage of achieving high welding quality, but has the disadvantage of slow welding speed. It has the disadvantages of being slow and having low wire welding efficiency. As a means of improving the welding speed and welding efficiency of TIG welding, a hot wire TIG welding method is used in which the wire supplied to the welding area is preheated.

The principle of the hot wire TIG welding method will be explained below with reference to FIG. In FIG. 2, reference numeral 1 denotes a welding power source, and a power source with direct current constant voltage characteristics is generally used.

2 is a non-consumable electrode, and 3 is a base material. The positive output of the welding power source 1 is connected to the base metal 3, and the negative output is connected to the non-consumable electrode 2, and a TIG welding current is passed between the base metal 3 and the non-consumable electrode 2 to create a TIG welding arc (hereinafter referred to as TIG). (referred to as an arc) 4 continues. On the other hand, the wire 5 is supplied to the welding part within the TIG arc by rotating the feed port 6 with a wire feeding electric motor (hereinafter referred to as electric motor) 7. The AC power source for wire heating (hereinafter referred to as heating power source) 9 is:
An alternating current heating current is passed between the heating electrode 8 provided near the tip of the wire 5 and the base material 3 to preheat the wire 5. The heating power source 9 includes an interval switching circuit 9a that performs switching control on DC input to obtain an arbitrary AC output;
A transformer 9b is connected to the load side of the inverter switching circuit 9a and performs voltage conversion and insulation. Further, the rotational speed of the electric motor 7 is controlled by a motor control circuit 13.

In this way, conventional welding equipment attempts to improve the welding speed and efficiency of TIG welding by feeding the wire 5 heated by AC power to the welding part in the TIG arc 4 using the electric motor 7 and the feeding roller 6. It is something to do.

Problems to be Solved by the Invention However, in such a conventional welding device, the rotational speed of the electric motor 7 is adjusted so that the tip of the wire 5 is supplied to the welding part while stably contacting the surface of the base body 33 in a solid state. The problem is that the setting tolerance for the rotational speed is extremely narrow, and it is often impossible to maintain a stable insertion state due to variations in the arc length of the TIG arc 4 or changes in the wire insertion position due to the curl of the wire 5. was there. In other words, if the arc length becomes long or the tip of the wire enters the center of the TIG arc 4 too much due to the winding of the wire, the wire will become over-molten and will migrate to the base metal 3 in the form of droplets. The tip of the wire separates from the base material 3. When the tip of the wire separates from the base material 3 in this way,
The wire melts irregularly, which is unfavorable from the viewpoint of welding quality.

Moreover, this is also a factor that causes a failure of the heating power source 9, as described below.

The part of the wire tip away from the base material 3 is a TIG arc 4
floats in the plasma air, and its potential is intermediate between the base metal 3, which is the anode, and the non-consumable electrode 2, which is the cathode.At this time, the TIG output from the welding power source 1
A part of the welding current is shunted to the heating current side. This situation will be explained in detail with reference to FIG. In Figure 3, 1, 2, 3, 4, 5, 8
, 9, 9a, and 9b are the same as those shown in FIG. When the wire tip 5a is in a solid state and in stable contact with the base metal 3, the TI flowing out from the positive terminal 1a of the welding power source l
The G welding current 10 passes through the base metal 3, the TIG arc 4, and the non-consumable electrode 2 in this order to the negative terminal 1b of the welding power source 1.
Returning to , when the wire tip 5a is floating in the plasma of the TIG arc 4, a portion 11 of the TIG welding current 10
is the base metal 3, the output terminal in the heating power source 9 -@9c1, the secondary winding of the transformer 9b, the other end 9d of the output terminal of the heating power source 9, and then the heating electrode 8, the wire tip 5a, and the TIG arc 4. ,
The flow is divided through the non-consumable electrodes 2 in turn. Through such a path, the DC output current of the welding power source 1 is shunted to the secondary winding of the transformer 9b in the heating power source 9, so that the transformer 9b is DC excited, but the amount of DC excitation is within the permissible limit. When the value exceeds 1, the transformer 9b becomes magnetically saturated, and the primary current increases abnormally, and its value may become several times as much as the normal value. Such an abnormal increase in the primary current of the transformer 9b often caused malfunctions of the heating power source 9, such as burnout of the transformer 9b in the heating power source 9 and damage to the inverter switching circuit 9a.

The present invention solves these conventional problems,
Pot wire type T that can prevent the heating power supply transformer from burning out and the inverter switching circuit from being destroyed.
The purpose is to provide an IG welding device.

Means for Solving the Problems In order to achieve the above objects, the present invention provides a welding power source connected to a non-consumable electrode and a base material, and a filler material supplied by a wire feeding electric motor and a feeding roller. , a heating electrode provided near the tip of the filler metal, a wire heating AC power source and a condenser connected to the heating electrode and the base metal, and a capacitor at one end of the output end of the wire heating AC power source. One end of the capacitor is connected to the wire, the other end of the capacitor is connected to the heating electrode, and the other end of the output end of the AC power supply for wire heating is connected to the base material.

The impedance Z of the capacitor connected to the output side of the power supply for action heating can be expressed as Z=1/2πfC (Ω) (1). However, in equation (1), f is the frequency of the voltage applied to the capacitor, C is the capacitance of the capacitor, and n is the constant of pi. (As shown in equation 1, the capacitor acts as a very large impedance for DC voltage components and blocks the current, but for AC voltage components, depending on the frequency f, ( 1) Allow current to pass while having an impedance of a value calculated by the formula.

The hot wire type TIG welding device of the present invention has the structure described in 11f, in which the AC heating current output from the heating power source is smoothly passed while blocking the DC current that is shunted from the welding power source to the heating power source using a capacitor. Magnetic saturation of the transformer in the power supply and the resulting failure of the heating power supply can be prevented.

Embodiment 7 FIG. 1 shows the configuration of an embodiment of the present invention, and the only difference from the conventional example shown in FIG. 2 is that a capacitor 12 is connected to one end of the output side of the heating AC power source 9. The same structural parts will be described with the same reference numerals.

Reference numeral 1 denotes a welding power source, and a power source with direct current constant voltage characteristics is generally used. 2 is a non-consumable electrode and 3 is a base material. 4 is a TIG arc generated between the base material 3 and the non-consumable electrode 2. 5 is a wire which is a filler material, 6 is a feeding roller,
7 is a wire feeding electric motor, and 8 is a heating electrode provided near the tip of the wire 5. Reference numeral 9 denotes an AC power supply for wire heating, which includes an interval switching circuit 9a for controlling switching of DC input to obtain an arbitrary AC output, and a transformer connected to the load side of this inharter switching circuit 9a for voltage conversion and insulation. 9b. A capacitor 12 is connected between the heating electrode 8 and the transformer 9b. 13 is a motor control circuit.

Next, the operation of the above embodiment will be explained. Welding 8 The positive side output of the power supply 1 for welding is connected to the base metal 3, and the negative side output is connected to the non-consumable electrode 2, and by flowing TIG welding current between the base metal 3 and the non-consumable electrode 2, TIG arc 4
continues to occur. The wire heating AC current a9 preheats the wire 5 by passing an AC heating current between the heating electrode 8 provided near the tip of the wire 5 and the base material 3. The DC current branched from the welding power source 1 to the heating AC power source 9 is blocked by the capacitor 12, and the AC heating current output from the heating AC power source 9 flows smoothly. The wire 5 is supplied to the welding part in the TIG'7-k 4 by rotating a feeding roller 6 by a wire feeding electric motor 7. The rotational speed of the electric motor 7 is controlled by a motor control circuit 13.

In this way, according to the embodiment, the heating AC power source is removed from the welding power source 1 by the action of the capacitor 12 connected between one end of the transformer 9b on the output side of the heating AC power source 9 and the heating electrode 8. This allows the AC heating current output from the heating AC power source 9 to flow smoothly while blocking the DC current branched into the heating AC power source 9, thereby preventing magnetic saturation of the transformer 9b in the heating AC power source 9 and the resulting heating. This has the effect of being able to prevent failures of the AC power supply 9 for use.

Effects of the Invention As described above, according to the present invention, it is possible to prevent the direct current component of the TIG current from flowing in a shunted manner into the heating power supply.
This prevents equipment failures such as burnout of the transformer in the heating power supply and destruction of the inverter switching circuit.
A highly reliable Hot Y A1 type i'lG welding device can be realized.

[Brief explanation of drawings]

FIG. 1 shows a hot wire type TIG according to an embodiment of the present invention.
Figure 2 is a schematic diagram of the welding device; Figure 2 is a schematic diagram of a conventional hot wire TIG welding equipment; Figure 3 is a diagram to explain that the TAG welding current is divided into the heating power source via the TIG arc. FIG. 2 is a schematic configuration diagram similar to FIG. 2; 1. Welding power source, 2. Non-consumable electrode, 3. Base material,
5. Melting filler jvA (wire), 6... Feeding roller, 71
0... Electric motor for wire feeding, 8... Heating electrode, 9... AC power source for wire heating (heating power source), 1 2... Capacitor.

Claims (1)

[Claims] a welding power source connected to a non-consumable electrode and a base metal; a filler metal supplied by a wire feed motor and a feed roller; a heating electrode provided near the tip of the filler metal; comprising an AC power source for wire heating and a capacitor connected to the heating electrode and the base material, one end of the capacitor being connected to one end of an output end of the AC power source for wire heating;
A hot wire type TIG welding device, wherein the other end of the capacitor is connected to the heating electrode, and the other end of the output end of the wire heating AC power source is connected to the base material.