JPH0223274B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to copper or copper alloys or aluminum,
Alternatively, it relates to a MIG welding method using a so-called highly conductive electrode wire such as an aluminum alloy.

Conventionally, MIG welding has been performed using a curved torch as shown in FIG. 1 using a highly conductive electrode wire. That is, a tip 5 is provided at the free end of the torch neck 2, which is made up of a tubular conduit 3 and an insulating jacket 4, and a guide liner 22, which is made up of an electrically insulating liner 20 and a restraining member 21, is provided at the axial center of the torch neck. MIG welding was performed by electrically insulatingly guiding the electrode wire through the guide liner and supplying power to the chip through the tubular conduit. By the way, in this type of curved torch, the tip is a consumable part that needs to be replaced as needed, and the length of the tip is limited to a certain degree because it is necessary to ensure operability of the torch. Ta. In this way, the current-carrying part of the electrode wire by the chip is relatively short, and
The arc heat generated during MIG welding brings the chip into a high-temperature, softened state, which causes the surface of the inner hole drilled in the chip to wear out, making it difficult to conduct electricity to the electrode wire. As a result, welding becomes uncertain and good welding results cannot always be obtained. Furthermore, when the surface of the inner hole of the chip is worn out as described above, the electrode wire will be damaged at the worn part of the inner hole of the chip because the highly conductive electrode wire made of copper or copper alloy or aluminum or aluminum alloy is relatively soft. Chips of the electrode wire accumulate in the inner hole of the chip and obstruct the feeding of the electrode wire, resulting in a drawback that uniform welding results cannot be obtained. Furthermore, in the past, a guide liner was sometimes used in which a tube-shaped restraining member made of iron or stainless steel was arranged inside an electrically insulating tube as shown in FIG. However, there was a drawback that welding defects occurred due to poor current conduction and poor feeding of the electrode wire. In addition, at least at the curved portion of the curved torch, the electrode wire comes into contact with the wall of the inner hole of the restraint member, but as mentioned above, the restraint member is generally made of a so-called high-hardness material such as iron or stainless steel. As a result, the relatively soft electrode wire was plucked or scraped on the inside of the curved portion of the restraining member, causing damage to the surface of the electrode wire, further promoting failure of current flow to the electrode wire due to the chip. . Moreover, the chips of the electrode wire described above are transported in the restraining member of the wire guide along with the electrode wire toward the chip, but the chips of the electrode wire are deposited in the restraining member or the electrode wire feeding passage of the chip. prevents the feeding of the electrode wire,
Finally, the drawback was that it made it impossible to feed the electrode wire.

An object of the present invention is to provide a MIG welding method using a highly conductive electrode wire that eliminates the above-mentioned conventional drawbacks.

The welding method according to the present invention will be explained in detail below with reference to the illustrated embodiments. In Figure 2, 1
2 is a torch holder that is held by an operator; 2 is a torch neck composed of a tubular conduit 3 and an insulating jacket 4; the base of the torch neck 2 is supported by the torch holder 1; A chip 5 is detachably supported. 6 is a gas nozzle detachably supported on the free end side of the torch neck 2 via an insulating cylinder 7 so as to substantially cover the tip 5; 8 is a gas nozzle whose material has an electrical resistance of approximately 10 μΩ·cm;
It is a guide liner with good conductivity that does not exceed 200 mm, and is made of, for example, copper wire material arranged in a spiral shape with an appropriate distance between each other. That is, the inside and outside of the guide liner communicate with each other through a spiral space. 9
1 is a shielding gas nozzle, and the shielding gas appropriately introduced into the tubular conduit 3 through the torch holder 1 is supplied from the gas nozzle 9 to the welding position through the gas nozzle 6. Further, the welding current is appropriately applied to the tubular conduit 3 and the guide liner 8 through the torch holder 1.

In the above, for example, by operating the lever 10 of the torch holder 1, an electrode wire feeding device (not shown) is activated, and a highly conductive electrode wire, for example, an aluminum wire is fed to the tubular conduit 3 and the guide liner 8. Welding is performed while electricity is applied and shielding gas is supplied.

In this case, since the aluminum wire contacts the inner surface of the guide liner 8 over a considerable length at least at the curved portion of the curved torch, power is supplied for welding at the corresponding contact portion, and power is also supplied to the tip portion in the same manner. It will be done.

According to experiments conducted by the inventor of the present application, if a material with an electrical resistance of approximately 10 μΩ・cm is selected as the material for the guide liner 8, the voltage drop between the wire contact part inside the guide liner and the chip is small, and the voltage drop between the two is approximately Power is supplied with a similar probability, and it has been confirmed that if the material has a high electrical resistance, arcing will occur frequently even at the guide liner abutting part, making it impractical. Note that when the spirally formed guide liner with good conductivity contacts the inner surface of the tubular conduit 3 near the curved part of the curved torch as shown in FIG. When a current is supplied, the current also flows through the guide liner 8 from the contact portion between the tubular conduit 3 and the guide liner 8, so that the tubular conduit 3 and the guide roller 8
The situation is the same as when welding current is supplied to both. Note that if the guide liner is formed in a spiral shape, the guide liner itself has flexibility, so even if it is a curved torch, the guide liner can be replaced easily and quickly due to its bendability. .

In FIG. 4, reference numeral 11 denotes a guide liner formed by bending a highly conductive member, such as a steel pipe, and this guide liner 11 is suitably provided with communication holes 12 in the radial direction so that the inside and outside communicate with each other. has been done. Further, the shielding gas is supplied to the inner space 13 of the guide liner 11 or the tubular conduit 3 and the guide liner 1.
1 from the space 14 formed between the two. 15
Reference numeral 17 indicates a chip which is removably attached to the end of the torch neck 2 by means of a cap nut 16, and 17 is a chip which is arranged at the free end of the torch neck 2 by means of a cap nut 16, for example.
A refractory member, for example, tungsten or a sintered alloy whose main component is tungsten, is integrally supported by the refractory member. When performing MIG welding using a highly conductive wire with the above configuration, since the poorly soluble member 17 is provided, arc heat is blocked by the hardly soluble member 17, resulting in a thermal influence on the chip 15, the tubular conduit 13, etc. Even when the so-called arc length between the electrode wire and the object to be welded becomes long, the chip 15 will not be burnt out due to the provision of the poorly soluble member 17. In addition, in FIG. 4, although it is disadvantageous in some respects, it is also possible to omit the provision of the radial communication hole 12 that communicates the inside and outside of the guide liner 11. The guide liner can also be formed into a honeycomb spiral shape, although this is somewhat disadvantageous in FIGS. 2 and 3.

In FIGS. 2, 3, and 4, the guide liner can be constructed of various steel materials and a highly conductive member disposed at least on the inner surface of the steel materials. In this case, a plating layer or a coating layer made of gold, silver, copper, etc. can be used as the highly conductive material, but there is a concern that the processing work required to manufacture the guide liner will be increased, and therefore copper, copper alloy, or aluminum may be used. Alternatively, it is preferable to form the guide liner from an aluminum alloy. In addition, considering the durability against friction between the guide liner and the electrode wire, the ability to maintain the shape of the guide liner itself, the conductivity of welding current, and the economy of manufacturing the guide liner, it is recommended that the guide liner be made of copper or a copper alloy. It is best to form it by

As shown in FIGS. 2, 3, and 4, if the guide liner has a radial communication path that communicates between the inside and outside, the shielding gas will flow into or out of the guide liner, and the electrode In order to reduce the friction between the wire and the guide liner, if air is mixed into the guide liner as the electrode wire is fed, the air will be disturbed by the flow of shielding gas inside and outside the guide liner as described above and will be guided to the welding position. The amount of air lost is extremely reduced, making it possible to obtain good welds. Furthermore, a very small amount of chips are generated due to the contact between the electrode wire and the guide liner, but the fact that the guide liner has a radial communication path that communicates with the inside and outside, and the shielding gas flows through the guide liner. To flow into or out of
Most of the small amount of chips mentioned above comes off from the electrode wire feeding path, so there is no risk of chips accumulating in the electrode wire feeding path and obstructing the electrode wire feeding, resulting in a good welded area. can be obtained.

As explained above, it is preferable to feed power to the electrode wire from both the guide liner and the tip because the power can be fed more reliably, but it is also possible to omit the power feeding tip at the tip of the curved torch.

It is possible to form the guide liner only from steel material, but in this case, as mentioned above, the surface of the soft and highly conductive electrode wire may be damaged, resulting in poor conduction, or chips may be generated, causing the electrode wire to become damaged. Moreover, due to the electrical resistance of the steel itself, it becomes red hot due to heat generated by so-called I ² R, which is undesirable, and the current transmission efficiency to the electrode wire is not as good as that of a guide liner made of steel material. It is not possible to perform good welding.

Although various embodiments of the present invention have been shown above, the present invention is not limited to these embodiments, and can be modified by appropriately combining each part of the above embodiments or replacing them with equivalent members. Various modifications can be made.

As described above, according to the present invention, power is supplied to the electrode wire over a considerable period of time, and at least the guide liner that contacts the electrode wire is formed of a highly conductive material, so that the electrode wire The welding current can be reliably transferred to and from the wire, and good MIG welding using highly conductive wire can be reliably performed. Furthermore, since the inner surface of the guide liner that the electrode wire comes into contact with is made of at least a relatively soft and highly conductive material, the surface of the highly conductive electrode wire is almost never scratched or scraped. Therefore, a highly conductive electrode wire can be used without causing problems such as poor current flow to the electrode wire or poor feeding of the electrode wire due to accumulation of chips in the electrode wire feeding path. Can perform good MIG welding.

[Brief explanation of drawings]

FIG. 1 is a front sectional view of the main part of a device used for conventional MIG welding, FIG. 2 is a front sectional view of the main part of a device suitable for carrying out the method of the present invention, and FIGS. The figures are diagrams showing other embodiments corresponding to FIG. 2, respectively. 2... torch neck, 3... tubular conduit, 5,
15...chip, 8,11...guideliner.

Claims (1)

[Scope of Claims] 1. A highly conductive electrode that is provided with a highly conductive guide liner that can come into contact with the electrode wire at least at the curved portion of the curved torch, and that is welded while supplying current to the electrode wire through at least the guide liner. MIG welding method using wire. 2. The MIG welding method using a highly conductive electrode wire according to claim 1, wherein the guide liner communicates with the inside and outside through a radial communication path. 3. The MIG welding method using a highly conductive electrode wire according to claim 1 or 2, wherein the guide liner is made of copper or a copper alloy. 4. The guide liner uses a highly conductive electrode wire according to claim 1 or 2, in which a highly conductive member is disposed at least on the inner surface.
MIG welding method. 5. The MIG welding method using a highly conductive electrode wire according to claim 4, wherein the highly conductive member disposed on at least the inner surface of the guide liner is a plating layer or a coating layer. 6. The MIG welding method using a highly conductive electrode wire according to any one of claims 1 to 5, wherein the guide liner is a flexible long wire wound around the guide liner. 7. MIG using the highly conductive electrode wire according to any one of claims 1 to 6, wherein the highly conductive electrode wire is made of copper or a copper alloy.
Welding method. 8. The MIG welding method using a highly conductive electrode wire according to any one of claims 1 to 6, wherein the highly conductive electrode wire is made of aluminum or an aluminum alloy. 9. A tip is provided at the free end of the curved torch, and the electrode wire is welded while being energized from the tip. MIG welding method. 10. Using the highly conductive electrode wire according to any one of claims 1 to 9, the curved torch is provided with a poorly soluble member having a perforated hole substantially in the axial center at the free end of the curved torch. MIG welding method. 11. The MIG welding method using a highly conductive electrode wire according to claim 10, wherein the hardly soluble member is ceramic. 12. The MIG welding method using a highly conductive electrode wire according to claim 10, wherein the hardly soluble member is tungsten or a sintered alloy containing tungsten as a main component. 13. The MIG welding method using a highly conductive electrode wire according to claim 10, wherein the hardly soluble member is carbon or graphite.