KR100770748B1 - Wire heating apparatus for metal inert gas welding - Google Patents

Abstract

A wire heating apparatus for metal inert gas welding is provided to improve welding efficiency and welding productivity by metal inert gas welding. A wire heating apparatus for metal inert gas welding includes a torch(30), a welding tip, a nozzle, a heating tip, a wire feeding unit(20) and a heating power supply(40). The torch applies electricity to a wire with using inert gas as protective gas. The wire passes through the torch. The welding tip covers the wire in a front part of the torch. The heating tip covers the wire in a rear part of the torch. The nozzle covers the welding tip and heating tip. The wire feeding unit is installed on the rear part of the torch and consecutively feeds the wire inside the torch. The heating power supply is connected to the welding tip and the heating tip. One electrode of the heating power supply is connected to the welding tip. Another electrode of the heating power supply is connected to the heating tip.

Description

Wire heating apparatus for mig welding {Wire heating apparatus for Metal Inert Gas welding}

1 is a conceptual diagram schematically showing a general MIG welding apparatus,

Figure 2 is a partial cutaway cross-sectional view showing an enlarged torch tip in a general MIG welding apparatus,

3 is a graph showing the relationship between current and arc pressure in a general MIG welding method;

4 is a conceptual view schematically showing a wire heating device for mig welding according to the present invention;

5 is a schematic diagram showing an enlarged portion of a welding tip and a heating tip in a wire heating device for mig welding according to the present invention;

6A and 6B are cross-sectional views schematically illustrating penetration and bead shapes, respectively, through the general MIG welding method and the MIG welding method of the present invention.

* Description of Major Symbols in Drawings *

10: welding power source 20: wire feeder

25: wire 30: torch

31: nozzle 32: welding tip

33: heating tip 40: heating power

M: Base material

The present invention relates to a mig welding device, and more particularly, to a wire heating device for mig welding, in which a heating device capable of heating the wire is installed on the mig welding device to increase the hardfacing effect and improve welding efficiency and productivity. It is about.

In general, arc welding is one of welding methods for generating an electric arc and melting the base metal with a heat source to perform welding.

As described above, inert gas arc welding among various arc welding methods is a method of welding while inert gas is supplied from a torch to a welding part through a nozzle in order to weld a special welded part with air. Here, argon or helium is used as the inert gas, and tungsten rod or metal rod is used as the electrode.

This inert gas arc welding method is also called shielded arc welding, and is classified into two methods of using a heat source by tungsten arc in an inert gas atmosphere and a heat source by metal arc. In other words, there are non-consumable and non-melting types that do not melt depending on the electrode used as the heat source.

Here, the non-consumable type is referred to as shielded inert gas tungsten arc welding or TIG welding because it uses a tungsten electrode, and the consumption type uses inert gas arc welding or MIG since a long core wire filler metal is used. (MIG) is called welding method.

1 and 2 show a conventional MIG welding apparatus used in the MIG welding method described above, and include a torch 30, a wire feeding device 20, and a welding power supply 10.

In other words, one electrode of the welding power supply 10 is connected to the base material M by the welding cable, and the other electrode is connected to the welding tip 32 provided at the tip of the torch 30 to weld the center of the welding tip 32. Apply electricity to the wire 25 penetrating the. That is, the torch 30 can generate an arc between the base material M and the wire 25 by applying electricity to the wire 25 while using an inert gas as a protective gas. At this time, the wire 25 made of a material similar to the base material M is alloyed while filling the molten portion, thereby performing welding.

In addition, the wire 25 is continuously supplied into the torch 30 by a wire feeding device 20 including a wire spool 21, a feeding motor, a roller, and the like. In addition, the torch 30 has a nozzle 31 formed at a tip thereof, a welding tip 32 is built in the center of the nozzle 31, and a wire 25 is transferred to the center of the welding tip 32. .

The MIG welding apparatus configured as described above supplies the wire 25 at room temperature in a normal cold-wire form. At this time, the electrical contact with the wire 25 occurs at the end of the welding tip 32, the heat for melting the wire 25 is received from the arc, the end of the melting from the end of the welding tip 32 There are two forms of heat received while energizing the current while going.

Therefore, in order to cause a large amount of melting, a large amount of current must be flowed, and the increase in the arc current causes an increase in the arc pressure, thereby increasing the penetration depth at the weld section. Figure 3 is a graph showing the relationship between the current and the arc pressure, it can be seen that the wire feed rate and the magnitude of the welding current has a linear relationship.

However, the welding process for hardfacing (surface hardening) requires properties different from those of the arc welding described above. That is, in order to increase the hardfacing effect, the melting of the base material M is minimized in the cross section of the weld to minimize dilution, thereby increasing the stacking amount and reducing the penetration.

Thus, in order to enhance the hardfacing effect described above, a TIG welding method for supplying a wire in a hot-wire form has been used. However, the TIG welding method is an arc welding method using a tungsten rod as an electrode. 21 ~ 48%) and welding productivity was significantly lower than the welding efficiency (66 ~ 85%) and welding productivity of MIG welding.

The present invention has been made to solve the conventional problems as described above, by installing a heating power source and a heating tip that can heat the wire in the MIG welding apparatus to increase the hardfacing effect and at the same time improve the welding efficiency and productivity To provide a MIG welded wire heating device.

The configuration of the present invention for achieving the above object, while continuously feeding the wire to the welding tip provided at the tip of the torch by a wire feeding device, between the wire and the base material by connecting a welding power source to the welding tip and the base material, respectively In welding by generating an arc, a heating tip through which a wire passes is mounted inside the rear of the torch, and one electrode of a heating power source is connected to the heating tip to heat the wire passing through the torch, and the welding is performed. It is characterized by connecting the other electrode of the heating power source to the tip.

When described in detail with reference to the accompanying drawings a preferred embodiment of the present invention. Here, the technical configuration of the present invention is the same as or similar to the MIG welding apparatus described in the above-described prior art configuration for the same reference numerals are applied to the description and shown that it has been shown in advance.

4 to 6B illustrate a wire heating apparatus for mig welding according to the present invention, and includes a torch 30, a wire feeding device 20, a welding power source 10, and a heating power source 40.

4 and 5, the torch 30 serves to apply electricity to the wire 25 while using an inert gas as a protective gas, and the torch 30 is connected to the gas container 22. Injecting an inert gas such as helium or argon gas. Although not shown in the drawings, when the torch 30 is water-cooled, a cooling hose for cooling the torch 30 may be further connected.

This, the torch 30 in the front inside the wire 25 is provided through the center, the welding tip 32 is covered on the outside of the wire 25, the nozzle 31 outside the welding tip 32 Is covered. In addition, the inside of the rear of the torch 30 is also provided with a wire 25 penetrating through the center thereof, a heating tip 33 is covered outside the wire 25, and a nozzle 31 outside the heating tip 33. Is covered.

At this time, the distance between the heating tip 33 and the welding tip 32 is as close as possible to solve the problem of lowering the wire 25 feedability due to the heating of the wire 25.

In addition, a wire feeding device 20 is installed at the rear of the torch 30 so that the wire 25 can be continuously supplied into the torch 30. In the wire feeding device 20, the wire 25 is wound around the wire spool 21, and the wire 25 is pushed or held by a roller (not shown) driven by a feeding motor (not shown). Pull to feed torch (30). At this time, the wire feeding device 20 is selected and applied to any one of the push (push), pull (pull) and push-pull (push-pull) according to the feeding method.

The welding tip 32 and the base material (M) as described above connects a welding power source 10 to apply electricity to the wire 25. That is, one electrode of the welding power source 10 is connected to the base material M, and the other electrode of the welding power source 10 is connected to the welding tip 32.

In addition, a heating power source 40 is connected to the welding tip 32 and the heating tip 33 to heat the wire 25. That is, one electrode of the heating power supply 40 is connected to the welding tip 32, and the other electrode of the heating power supply 40 is connected to the heating tip 33.

Referring to the operation and effects of the present invention configured as described above in detail.

In order to perform mig welding for hardfacing through the wire heating device for mig welding of the present invention, the heating power source 40 is supplied while continuously supplying the wire 25 to the torch 30 through the wire feeding device 20. The wire 25 is driven to heat the wire 25 passing through the heating tip 33, and the welding power source 10 is driven to apply electricity to the wire 25 passing through the welding tip 32.

In this case, while the contact between the wire 25 and the welding tip 32 occurs, an arc is generated between the base material M and the wire 25, and the wire is formed in the melting part while melting the base material M due to the arc. 25) is filled and welded.

Here, the present invention is capable of heating the wire 25 through the configuration of the heating power source 40 and the heating tip 33 as described above, thereby minimizing the melting of the base material (M) in the cross section of the weld portion Therefore, the dilution rate can be minimized to increase the hardfacing effect.

That is, since the wire 25 used for welding is heated in advance before being supplied to the welding tip 32, supply of a large amount of current is not required for heating the wire 25. Therefore, since the penetration depth of the weld section is not increased, the material of the hard facing does not mix deeply with the base material M, and the lamination amount at the weld is increased to minimize the dilution rate, thereby increasing the hard facing effect. It is.

In order to describe this in more detail, the dilution rate described above may be defined by the following equation through the following figure.

In other words, it can be seen that as the Ap (infiltration) decreases and the Ar (lamination amount) increases, the dilution rate decreases.

Thus, referring to the drawings shown in Figures 6a and 6b of the accompanying drawings, Figure 6a schematically shows the shape of the weld and the bead welded through a general MIG welding method, Figure 6b is a MIG using the wire heating apparatus of the present invention The shape of the weld and the bead welded by the welding method is schematically shown, and the welding method of FIG. 6B (the present invention), in which the penetration is small and the lamination amount is high and the height of the beads is high, is a more suitable process for hardfacing.

Furthermore, the present invention can further improve the welding efficiency and the welding productivity by welding through the MIG welding method using a wire heating device rather than the TIG welding method.

On the other hand, the present invention has been described in detail only with respect to the specific examples described above it is obvious to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, it is obvious that such variations and modifications belong to the appended claims. will be.

As described above, the present invention, by applying the MIG welding method by heating the wire, the dilution rate is very useful in the hardfacing process is advantageous, it is possible to improve the welding efficiency and welding productivity through the MIG welding There is also an effect.

Claims (1)

In the continuous supply of the wire to the welding tip provided at the tip of the torch by a wire feeding device, by connecting a welding power source to the welding tip and the base material, by generating an arc between the wire and the base material for welding, A heating power source is mounted on the heating tip 33 to mount a heating tip 33 through which the wire 25 passes inside the rear of the torch 30, and to heat the wire 25 passing through the torch 30. Mig welding wire heating device, characterized in that one electrode of the (40) is connected, and the other electrode of the heating power source (40) is connected to the welding tip (32).

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