JPH0570551B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an arc welding machine, and more particularly to an arc welding machine characterized by the structure of a welding wire that is projected onto a part to be welded and acts as a filler metal. It is related to.

[Prior art]

In a conventional arc welding machine, as shown in FIG. 3, a welding wire 6, which is a consumable electrode, protrudes from a power supply chip 4 of a welding torch 2, and the welding wire 6 and the material to be welded are arranged opposite each other. A power cable 12 (12A, 1
2B), the welding wire 6 and the base material 8
The generation of the arc 14 is maintained between the two parts, thereby forming a weld bead 9 along the seam 8A. The welding wire 6 is wound around a wire reel 16, passed through a conduit cable 18, and held so that its tip protrudes from the power supply tip 4 of the welding torch 2. The reference numeral 20 is a feed roller for feeding out the welding wire 6, and the reference numeral 22 is a correction roller for keeping the welding wire 6A protruding from the power supply chip 4 in a straight state.

[Problem to be solved by the invention]

In the above-mentioned conventional arc welding machine, the straightness of the protruding wire 6A protruding from the power supply chip 4 changes greatly due to slight curvature adjustment by the correction roller 22. adjustments were needed. Especially when the wire is unwound from the wire reel 16, the correction roller 2
Since the curvatures of the welding wires supplied to the welding wires 2 differ considerably, the amount of adjustment by the correction roller 22 naturally differs, and adjustments must be made taking this into consideration. Furthermore, the welding wire 6 is
Even if the curvature of the welding wire 6 is adjusted, the conduit cable 18 is often used in a bent state, and the welding wire 6 is deformed by passing through the conduit cable 18, and the power supply chip 4 The welding wire protruding from the conduit cable 18 becomes bent due to the deformation received from the conduit cable 18.
As shown in FIG. 4, there was a problem in that the protruding portion 6A of the wire did not match the seam 8A of the base material 8, making it impossible to perform accurate welding.

Furthermore, even if an attempt is made to increase the wire protrusion (WL) in order to increase the melting speed of the welding wire 6,
Since the amount of misalignment between the tip of the welding wire and the seam 8A increases accordingly, there is a natural limit to the melting speed, that is, the welding speed.

The present invention has been made in view of the problems of the prior art described above, and its purpose is to provide an arc welding machine capable of always keeping a welding wire protruding toward a part to be welded in a straight state. It's about doing.

[Means for solving problems]

An arc welding machine according to the present invention has a structure in which a welding wire protrudes from a part to be welded, and the welding wire has a shape memory treatment that takes a straight shape when the temperature reaches a predetermined temperature or higher. It is characterized by the fact that it has been

[Effect]

The welding wire protruding toward the part to be welded is heated by arc heat and regenerated into a straight shape stored in advance. Therefore, during welding work, the welding wire is always kept straight within the area affected by the arc heat. Therefore, it is easy to hold the tip of the welding wire in a position facing the seam of the base metal, and the tip of the welding wire does not come off significantly from the seam of the base metal.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

FIG. 1 shows an arc welding machine in which welding wire is used as a consumable electrode. In this figure, welding wire 2 wound around a wire reel 16 is shown.
6 is inserted into the conduit cable 18 and led to the welding torch 2, and its tip protrudes from the power supply chip 4, and is guided to a predetermined position by a feed roll 20 provided in the middle of the wire feed path. It is now being sent at a faster speed.

The welding wire 26 is a Fe-27Ni-0.4C alloy wire that has been subjected to shape memory treatment so that it assumes a straight shape when the temperature reaches a transformation temperature (400°C) or higher. The 27Ni-0.4C alloy wire is brought into a straight state and then wound around a wire reel 16 at a temperature below this transformation temperature.

As shown in FIG. 2, the tip of the welding torch 2 has a structure in which a welding wire 26 protrudes from a power supply chip 4, and a shielding gas as shown by arrow A is supplied to the outer periphery of the power supply chip 4. A gas nozzle 30 is formed for this purpose. Power supply chip 4
As shown in FIG. 2, the tip portion 4A of the gas nozzle 30 is formed at a position recessed inward from the lower end portion 30A of the gas nozzle 30, and the wire extension and wire protrusion amount (WL) are different from those of the conventional ones ( (see Fig. 4), and the welding wire 26 protrudes toward the seam 8A of the base material 8.
is sufficiently heated by the power generation resistance caused by the arc current to reach a temperature higher than the transformation temperature of the Fe-27Ni-0.4C alloy.

In this way, the welding wire 26 is heated to a temperature higher than the transformation temperature of the Fe-27Ni-0.4C alloy by the resistance heat generated within the power supply chip 4 and the heat transferred from the power supply chip 4, and is regenerated into a straight shape. The welding wire protrusion 26A that has come out of the welding wire 4 is in a straight state, and its tip is always aligned with the seam 8A of the base material 8.

According to this embodiment, the following effects can be obtained.

Since the welding wire protrusion 26A protruding from the power supply chip 4 can always be kept straight, if the welding torch 2 is accurately positioned with respect to the seam 8A, the tip of the welding wire protrusion 26A can always be kept straight. It can be positioned directly above the seam 8A, thereby making it possible to perform highly reliable welding.

Since no straightening rolls (see FIG. 3) are installed on the wire feeding path that feeds the welding wire to the welding torch 2, the number of work steps can be reduced and the length of the wire feeding path can be shortened.
Note that even if the straightening roll is installed in the middle of the wire feeding path, the straightening roll is not connected to the wire protrusion 2.
Since it can be used only for smooth feeding of the welding wire 26 within the conduit cable 18 without being used to correct the bend of the wire 6A,
There is no need to perform precise and complicated roll fine adjustment, and the adjustment work becomes easier.

Even if the conduit cable 18 is arranged in a complicated shape, the welding wire protrusion 26A is always in a straight state, so that the conduit cable 1
The restrictions on the arrangement shape of 8 are significantly relaxed.

Since the wire protrusion amount (WL) is large, a large amount of melting can be ensured, thereby increasing the melting speed of the welding wire 26 and dramatically improving welding efficiency. Furthermore, the adhesion of welding spatter to the power supply chip 4 is reduced, and the frequency of replacement of the power supply chip 4 is reduced.

Since the power supply chip 4 is located inward from the tip of the nozzle 30 that spouts the shielding gas, the flow of the shielding gas jetted from the nozzle 30 is smooth, and the occurrence of welding defects such as blowholes is suppressed.

In the above embodiment, the welding wire 26 is a Fe-27Ni-0.4C alloy that has been subjected to shape memory treatment. However, any material that can be subjected to shape memory treatment and can be used as a welding wire It is not limited to Fe-27Ni-0.4C alloy. Examples of this include e.g. Ti
−50Ni (transformation temperature 60 to 78℃), Ti−Ni−Cu (transformation temperature 80℃)
~85℃), Cu−13.5Zn−8Al (146℃), Au−
Examples include 29Cu−45Zn (at 57℃) and Fe−33Ni−10Co−4Ti.

In addition, although the case where the welding wire 26 is used as an electrode was explained in the said Example, it is clear that this invention can be applied also when a welding wire is used simply as a filler metal like TIG welding.

〔effect〕

As is clear from the above description, according to the present invention, it is possible to make the tip of the welding wire protrude accurately to a desired position, thereby making it possible to perform highly reliable welding.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of an embodiment of the present invention, Fig. 2 is a sectional view of the main part of the tip of the welding torch, Fig. 3 is an overall configuration diagram of a conventional arc welding machine, and Fig. 4 is the welding torch. FIG. 3 is a cross-sectional view of the main part of the tip. 2...Welding torch, 4...Power supply chip, 8...
Base metal, 8A... Seam, 10... Welding power source, 16...
...Wire reel, 18...Conduit cable,
20... Feeding roll, 26... Welding wire, 26
A...Welding wire protrusion, 30...Gas nozzle.

Claims (1)

[Claims] 1. An arc welding machine having a structure in which a welding wire protrudes from a part to be welded, characterized in that the welding wire is subjected to shape memory treatment so that it assumes a straight shape when it reaches a predetermined temperature or higher. arc welding machine.