JPH0352768A - Hot wire welding equipment - Google Patents

Abstract

PURPOSE:To suppress a blowhole and segregation by a vibrational effect of a molten pool by providing a wire heating power source on hot wire welding equipment and carrying a pulse current synchronized with current phase of an AC TIG arc to a wire from the reverse polarity of the AC TIG arc to a positive electrode. CONSTITUTION:An arc current 9 and a wire current 10 are carried to a TIG torch 11 and a wire torch 14, respectively and the arc is generated from the TIG torch 11 and the wire is heated by the applied current. With this current impressed on the wire, in a period of time when the arc current is changed from the positive electrode to a negative electrode, the arc current is detected by a current detector 6 and the current is applied to the wire by a wire current synchronization controller 7. Accordingly, the vibrational effect of the molten pool can be utilized positively and the blowhole and segregation can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hot wire welding device, and particularly to a welding device that is effective in reducing blowholes and unevenness in weld metal.

[Conventional technology]

Aluminum and argonium alloys often exhibit blowholes because the solubility of hydrogen in molten metal changes significantly as the temperature changes. On the other hand, when TIG welding aluminum alloys, the presence of an oxide film makes welding difficult, so we use an alternating current arc and set a period in which the cathode point of the arc is formed on the base metal side. The most common method is to use the cleaning effect of ion bombardment to destroy oxides on the surface of the base metal, and perform welding while removing the oxide film.

FIG. 3 shows an outline of a welding device conventionally used for hot wire TIG welding of aluminum ξ alloy. AC arc power supply 16, TIG torch 19, base material 1
At step 8, an alternating current arc is formed, and the additive wire 23 is supplied thereto using a wire feeding device 25. At this time, the wire heating power source 17 was used to apply a pulsed current to the wire, avoiding the cleaning period, to perform stable hot wire welding.

In the figure, 15 is a welding power source, 20 is a tungsten electrode, 21
is an arc, 22 is a bead, and 24 is a contact tip.

Figure 4 shows the arc current waveform (a) when using an AC TIG power supply that switches DC current and outputs a square wave AC current as an arc power supply, and the pulsed current waveform (b) that is used when current is passed through a conventional wire. ) indicates the timing of energization.

It is already known that when pulse current is applied to a wire, the arc current flowing through the molten pool and the strong magnetic field generated around the wire act to vibrate the molten pool. It was also effective in preventing blowholes and segregation, which tend to be problems during welding and overlay welding of copper alloy to aluminum alloy.

Figure 5 shows the force acting on the molten pool when pulse current is applied to the wire. In the figure, 26 is a TIG}-chi, 27 is a tungsten electrode, 28 is a base metal, 29 is an arc current, 30 is a weld pool,
31 is a Lorento force, 32 is an additive wire, and 33 is a wire torch.

[Problem to be solved by the invention]

As shown in FIG. 5, conventional hot wire welding has a problem in that the Loren force acting on the molten pool only acts in one direction. This is because the energization of the additive wire is synchronized with the opposite polarity of the arc current.

For this reason, it has the disadvantage that blowholes and segregation are likely to occur.

An object of the present invention is to apply a current to the wire when the polarity of the current is positive or reverse, without impeding the arc cleaning effect, and to greatly reduce the vibration of the molten pool and the deflection of the arc.

[Means to solve the problem]

According to the present invention, the above object is achieved by using an AC arc welding power source, a TI
In an AC TIG arc welding device equipped with a G-arc torch, an additive wire, and a wire feeding device, a wire heating power source is provided, and a pulsed current synchronized with the current phase of the AC TIG arc is applied to the wire. T.I.G.
This is achieved by passing a pulsed wire heating current from the opposite polarity of the arc to the positive polarity.

[Effect]

Thus, by applying current to the additive wire when the arc current reverses between positive and reverse polarity, the deflection of the arc and the roller acting on the molten pool are reversed. By minimizing the time during which the additive wire is energized during the reverse polarity of the arc current, the cleaning action of the base metal by the arc is not hindered.

(Embodiment of the Invention) An embodiment of the present invention is shown in FIG. Hot wire T
The IG power supply unit W1 includes a rectifier 2 that rectifies alternating current, transistors 3 and 3' that control arc current and wire current, respectively, wire current synchronous controller 7, high frequency transformers 4 and 4', and a rectifier 5 that rectifies output current. and 5', and current detectors 6 and 6' for detecting the output current and feeding it back to the wire current synchronous controller 7.

The arc current 9 is passed through the TIG}-chi 11, and the wire current lO is passed through the wire torch 14, each forming a closed circuit. An arc is generated from the TIGI chip 11, and the wire is heated by the current.

As shown in Figure 2, the current applied to this wire is determined by detecting the arc current with a current detector consisting of a Hall element during the period when the arc current changes from positive to reverse, and applying current to the wire by a wire current synchronous controller. energize. The boundary between positive and reverse polarity when the arc current value becomes 0 is detected, and a timer is used to control when to apply current to the wire. By minimizing the period during which the wire is energized when the arc is of positive polarity, hot wire TIG welding is possible without interfering with the cleaning effect of the arc on the base material.

〔Effect of the invention〕

According to the present invention, it is possible to actively utilize the vibration effect of the molten pool, and it is possible to suppress blowholes and segregation that tend to cause problems when welding aluminum alloys or dissimilar materials. Further, since arc deflection can also be controlled, unmelted portions of the open end can be prevented.

[Brief explanation of drawings]

FIG. 1 shows a hot wire TIG? according to an embodiment of the present invention. 8
Block diagram of the connection device, Fig. 2(a). (b) is an output waveform diagram of the welding current in the welding device, FIG. 3 is an explanatory diagram of the conventional hot wire TIG welding device, and FIG. 4 (a)
, (b) is an output waveform diagram of the welding current in the welding device, and FIG. 5 is an explanatory diagram showing the force acting on the molten pool when pulse current is applied to the wire. DESCRIPTION OF SYMBOLS 1... Welding power source, 6... Current detector, 7... Wire current synchronous circuit, 8... Current setting device, 9... Arc current path, 10... Wire current path, 11... ...TIG torch, 12...tungsten electrode, 13...arc, 14...wire torch. no! −Sakimata

Claims (1)

[Claims] In a hot wire welding device equipped with an AC arc welding power source, a TIG arc torch, additive wire, and a wire supply device, a wire heating power source is provided, and a pulse current synchronized with the current phase of the AC TIG arc is applied to the hot wire welding device. A hot wire welding device characterized in that it is configured to energize an additive wire to flow a pulsed wire heating current from the reverse polarity to the positive polarity of an AC TIG arc.