Non-consumable electrode type welding device and non-consumable electrode type welding method

Abstract

To reduce a heat load applied to a non-consumable electrode in a non-consumable electrode type welding in which a hot wire is used.SOLUTION: A non-consumable electrode type welding device 1 performs hot wire welding and is provided with a welding torch 10, a power supply unit 34 which supplies electric power to a welding wire 21 fed between the welding torch 10 and a base material 2; a first power source 40 for generating an arc between the welding torch 10 and the base material 2; and a second power source 41 for heating the welding wire 21. The welding torch 10 has: a non-consumable electrode 11; and a conductor 12 which is disposed around the non-consumable electrode 11, spaced apart from the non-consumable electrode 11. The first power source 40 is configured to be electrically connected to the base material 2 and the non-consumable electrode 11. The second power source 41 is configured to be electrically connected to the power supply unit 34 and the conductor 12.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a non-consumable electrode type welding apparatus and a non-consumable electrode type welding method.

Background Art

[0002] In recent years, in build-up welding, high efficiency and high quality are required while considering environmental resistance. Among various known welding methods, the consumable electrode type welding method is advantageous from the viewpoint of high efficiency. On the other hand, from the viewpoints of environmental resistance such as CO2 emissions, fumes, and slag disposal, and high quality such as a beautiful bead appearance and a low dilution rate, the non-consumable electrode type welding method is advantageous. Further, in the non-consumable electrode type welding method that is advantageous from the viewpoint of such high quality, as a method for ensuring a welding amount comparable to various consumable electrode type welding methods, a hot wire type welding method in which a wire heated by energization is fed toward a molten pool on the surface portion of the base material to perform welding is known.

[0003] As a welding apparatus for performing hot wire type welding, Patent Document 1 discloses a welding apparatus provided with a welding power source for generating an arc between a welding torch and a base material, and a hot wire power source for heating a welding wire. In this welding apparatus, the base material is connected to the positive electrode side of the welding power source, and the non-consumable electrode of the welding torch is connected to the negative electrode side of the welding power source. Further, in this welding apparatus, the welding wire is connected to the positive electrode side of the hot wire power source, and the non-consumable electrode is connected to the negative electrode side of the hot wire power source.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the welding apparatus described in Patent Document 1, both a plasma welding power source and a hot wire power source are connected to the non-consumable electrode of the welding torch. Therefore, during energization, current flows from the two power sources to the non-consumable electrode, and a large thermal load is applied to the non-consumable electrode. And the life of the non-consumable electrode is shortened by the thermal load that increases according to the magnitude of the flowing current. Therefore, the larger the current flowing through the non-consumable electrode becomes (higher deposition amount and higher efficiency), the more necessary it is to perform maintenance work to replace the non-consumable electrode in a short time operation. During the maintenance work, the welding apparatus has to be stopped, so the production efficiency will decrease.

[0006] In order to reduce the consumption of the non-consumable electrode as described above, there is also a measure to adopt a torch structure that directly or indirectly cools the non-consumable electrode, but the effect is not sufficient, and it also causes an increase in the cost and size of the welding torch.

[0007] Therefore, in non-consumable electrode welding using a hot wire, in order to avoid a decrease in production efficiency associated with the implementation of maintenance work on the non-consumable electrode and to avoid an increase in the cost and size of the welding torch, a new power supply structure for reducing the thermal load on the non-consumable electrode is required. This problem does not occur only when performing build-up welding, but also occurs when performing other weldings such as butt welding, overlap welding, and fillet welding.

[0008] The present invention has been made in view of the above circumstances, and an object thereof is to reduce the thermal load on the non-consumable electrode in non-consumable electrode welding using a hot wire.

Means for Solving the Problem

[0009] The present invention for solving the above problems is a non-consumable electrode type welding apparatus that performs hot wire welding, comprising a welding torch, a power supply unit that supplies power to a welding wire fed between the welding torch and a base material, a first power source for generating an arc between the welding torch and the base material, and a second power source for heating the welding wire, wherein the welding torch has a non-consumable electrode and a conductor disposed at a distance from the non-consumable electrode around the non-consumable electrode, the first power source is configured to be electrically connected to the base material and the non-consumable electrode, and the second power source is configured to be electrically connected to the power supply unit and the conductor.

[0010] According to another aspect, the present invention is a non-consumable electrode type welding method for performing hot wire welding, which uses a welding torch having a non-consumable electrode and a conductor disposed at a distance from the non-consumable electrode around the non-consumable electrode, energizes between the base material and the non-consumable electrode with a first power source to generate an arc, and energizes between the welding wire and the conductor with a second power source to heat the welding wire and perform welding.

Advantages of the Invention

[0011] In non-consumable electrode type welding using a hot wire, the heat load on the non-consumable electrode can be reduced.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

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Figure 8

Figure 9

Figure 10

Figure 11

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Figure 14

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each of the embodiments described below, a plasma welding apparatus is exemplified as a non-consumable electrode type welding apparatus. However, the non-consumable electrode type welding apparatus is not limited to the plasma welding apparatus, and may be other welding apparatuses classified as non-consumable electrode type, such as a TIG welding apparatus. In the present specification and drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

[0014] <First Embodiment> FIG. 1 is a diagram showing a schematic configuration of a hot wire type plasma welding apparatus 1 according to the first embodiment. FIG. 2 is a diagram further schematizing the plasma welding apparatus 1 of FIG. 1 and is a diagram for explaining the power supply structure of the welding torch and the welding wire.

[0015] The plasma welding apparatus 1 includes a welding torch 10, a wire feeder 20 that feeds a welding wire 21, and a wire feeding path 30 for feeding the welding wire 21 between a base material 2 to be welded and the welding torch 10.

[0016] The welding torch 10 has a tungsten electrode 11 which is an example of a non-consumable electrode, an insert chip 12 made of a conductor surrounding the tip of the tungsten electrode 11, and a shield cap 13 surrounding the insert chip 12.

[0017] Between the tungsten electrode 11 and the inner peripheral surface of the insert chip 12, a flow path is formed for supplying an inert gas such as argon gas or helium gas as a pilot gas, or a gas mainly composed of an inert gas and mixed with an active gas such as hydrogen gas. Similarly, between the outer peripheral surface of the insert chip 12 and the inner peripheral surface of the shield cap 13, a flow path is formed for supplying an inert gas such as argon gas or helium gas as a shield gas, or a gas mainly composed of these inert gases and mixed with an active gas such as hydrogen gas.

[0018] The insert chip 12 is formed of a metal material such as copper or a copper alloy (such as copper tungsten). As shown in FIG. 2, a cooling water flow path 14 through which cooling water circulates is formed inside the insert chip 12, and the insert chip 12 is cooled by the cooling water flowing through the cooling water flow path 14 during welding. An arc ejection hole 15 from which an arc 3 ejects is formed at the tip of the insert chip 12. Since the welding apparatus in this embodiment is a plasma welding apparatus, the arc 3 ejected from the arc ejection hole 15 is a plasma arc.

[0019] As shown in FIG. 1, the wire feeder 20 has a wire spool 22 around which the welding wire 21 is wound, a pair of feeding rollers 23 that send the welding wire 21 sent out from the wire spool 22 to the welding torch 10 side, and a motor 24 that is a rotational drive source of the feeding rollers 23.

[0020] The wire feeding path 30 is a feeding path for sending the welding wire 21 sent out from the wire feeder 20 to the vicinity of the tip of the welding torch 10, and is composed of a single part or a combination of multiple parts. The wire feeding path 30 according to the present embodiment is composed of a housing 31, a conduit liner 32, and a wire nozzle 33.

[0021] The housing 31 is provided in the middle part of the wire feeding path 30 and is arranged between the conduit liner 32 and the wire nozzle 33. A rod-shaped power supply electrode 34 is fixed to the housing 31 as a power supply part for heating the welding wire 21 by supplying power. The lower end of this power supply electrode 34 is always in contact with the welding wire 21 passing through the housing 31 by means of a spring (not shown).

[0022] The conduit liner 32 is arranged between the wire feeder 20 and the housing 31. One end of the conduit liner 32 is connected to the wire feeder 20, and the other end is connected to the housing 31. The welding wire 21 sent out from the wire feeder 20 passes through the inside of the conduit liner 32 and is sent to the housing 31.

[0023] The wire nozzle 33 extends from the housing 31 to the vicinity of the tip of the welding torch 10, and the portion in contact with the welding wire 21 inside the wire nozzle 33 is formed of an insulating material. The welding wire 21 passing through the housing 31 passes through the inside of the wire nozzle 33 and reaches the plasma arc 3 generated between the tungsten electrode 11 of the welding torch 10 and the base material 2.

[0024] The plasma welding apparatus 1 includes a plasma welding power source 40 as a first power source for generating a plasma arc between the welding torch 10 and the base material 2, and a hot wire power source 41 as a second power source for heating the welding wire 21.

[0025] As shown in FIG. 2, the plasma welding power source 40 is connected to the base material 2 and the tungsten electrode 11 of the welding torch 10. Specifically, the base material 2 is connected to the positive electrode side of the plasma welding power source 40, and the tungsten electrode 11 is connected to the negative electrode side of the plasma welding power source 40. Although not shown in the figure, in a normal plasma welding apparatus, a pilot arc with a relatively small current is passed between the tungsten electrode 11 and the insert tip 12 in advance so that the plasma arc 3 can be easily ignited, and a high-temperature gas flow (conductive gas flow) is discharged from the arc ejection hole 15. When welding, the base material 2, the pilot arc flame, and the tungsten electrode 11 are electrically connected by the plasma welding power source 40, whereby the plasma arc 3 is generated and the plasma arc current flows. That is, the plasma welding power source 40 has a configuration in which it is electrically connected to the base material 2 and the tungsten electrode 11.

[0026] The hot wire power source 41 is connected to the welding wire 21 and the insert tip 12. Specifically, the welding wire 21 is connected to the positive electrode side of the hot wire power source 41, and the insert tip 12 is connected to the negative electrode side of the hot wire power source 41. During welding, when the welding wire 21 fed toward the tip of the welding torch 10 contacts the plasma arc 3, the hot wire power source 41, the welding wire 21, and the insert tip 12 are electrically connected through the plasma arc 3 and the hot wire current flows. That is, the hot wire power source 41 has a configuration in which it is electrically connected to the welding wire 21 and the insert tip 12.

[0027] In this specification, for convenience of explanation, there may be a description to the effect that the hot wire power source 41 and the welding wire 21 are electrically connected. However, the state in which the hot wire power source 41 and the welding wire 21 are electrically connected means a state in which the hot wire power source 41 and the power supply electrode 34 shown in FIG. 1 are connected.

[0028] The schematic configuration of the plasma welding apparatus 1 according to the first embodiment has been described above. In this plasma welding apparatus 1, while the plasma welding power source 40 is connected to the tungsten electrode 11 of the welding torch 10, the hot wire power source 41 is connected to the insert chip 12 without being connected to the tungsten electrode 11.

[0029] Therefore, the plasma welding apparatus 1 according to the present embodiment can reduce the current flowing through the tungsten electrode 11 as compared with the welding apparatus described in Patent Document 1 in which both the plasma welding power source and the hot wire power source are connected to the non-consumable electrode. As a result, the heat load on the tungsten electrode 11 during welding can be reduced, so that the consumption due to overheating of the tungsten electrode 11 is suppressed, and the frequency of maintenance work such as electrode replacement associated with the consumption of the tungsten electrode 11 can be decreased. As a result, the operating time of the plasma welding apparatus 1 can be ensured to be longer, and the production efficiency of welded products can be improved.

[0030] In addition, in the plasma welding apparatus 1 according to the present embodiment, since the heat generation of the tungsten electrode 11 during welding can be suppressed, it is possible to perform desired welding even with a torch structure that does not have a water cooling structure for the tungsten electrode 11. That is, since the number of components constituting the welding torch 10 can be made smaller than the number of components of the electrode water-cooled torch, an economical plasma welding apparatus 1 can be configured, and the welding torch 10 can also be miniaturized.

[0031] Furthermore, when performing build-up welding with the plasma welding apparatus 1 according to the present embodiment, it is possible to ensure a deposition amount equal to or greater than that of the welding apparatus described in Patent Document 1, which is excellent in terms of the deposition amount. That is, the plasma welding apparatus 1 according to the present embodiment can improve the production efficiency by suppressing the consumption of the tungsten electrode 11 while maintaining excellent performance in terms of the deposition amount, and thus is particularly useful when performing build-up welding.

[0032] Incidentally, as a method of connecting the welding wire 21 and the insert chip 12 to the hot wire power source 41, for example, the welding wire 21 may be connected to the negative electrode side of the hot wire power source 41, and the insert chip 12 may be connected to the positive electrode side of the hot wire power source 41. However, considering the magnetic field formed by the current flowing through the welding wire 21 and the direction of the electromagnetic force determined by the direction of the magnetic field and the direction of the current, it is preferable that the welding wire 21 is connected to the positive electrode side of the hot wire power source 41 and the insert chip 12 is connected to the negative electrode side of the hot wire power source 41 as in the present embodiment.

[0033] As a result, the direction of the electromagnetic force acting on the tip of the welding wire 21 is the direction toward the center of the plasma arc 3. Therefore, even if droplets are generated by melting the tip of the welding wire 21, the droplets scatter toward the center of the plasma arc 3. Then, the droplets that have reached the center of the plasma arc 3 are more likely to fall into the molten pool formed on the surface of the base material 2 by receiving the downward force due to the arc force and the air flow. That is, by connecting the welding wire 21 to the positive electrode side of the hot wire power source 41 and the insert chip 12 to the negative electrode side of the hot wire power source 41, spatter adhesion to the outside of the molten pool can be suppressed, and the welding quality can be improved.

[0034] <Second Embodiment> Next, the plasma welding apparatus 1 according to the second embodiment will be described. The schematic configuration of the plasma welding apparatus 1 according to the second embodiment is the same as that of the plasma welding apparatus 1 according to the first embodiment except for the structure of the tip of the insert chip 12 described below. Therefore, in the following description, descriptions overlapping with those of the plasma welding apparatus 1 according to the first embodiment will be omitted.

[0035] FIG. 3 is a diagram corresponding to FIG. 2 and shows a schematic configuration of the plasma welding apparatus 1 according to the second embodiment. FIG. 4 is a diagram for explaining the tip structure of the insert chip 12.

[0036] As shown in FIG. 3, the insert chip 12 according to the present embodiment includes a chip body 12a made of a conductor, an arc ejection hole 15 from which an arc ejects, and a tungsten ring 16 attached to the tip of the chip body 12a.

[0037] The tungsten ring 16 is an annular member formed of tungsten or a tungsten alloy (an alloy such as lanthanum, cerium, or yttrium, which has a high melting point and enhances electron emission properties). In the present embodiment, since copper is used as the material of the chip body 12a, the tungsten ring 16 is an annular member made of a material having a higher melting point and better electron emission properties than the chip body 12a.

[0038] Note that the electron emission property is an index indicating the ease of electron emission from a member. For example, "member A has better electron emission properties than member B" means that member A has a higher melting point than member B, or the work function (physical property of the difficulty of electron emission) of member A is lower than that of member B, or it has both of the above two conditions. When electron emission occurs, the substance on the side that emits electrons loses particles that move violently, so collisions between particles are less likely to occur and the temperature of the substance decreases. That is, the member where electron emission occurs provides a cooling effect on other members around it. Therefore, since the tungsten ring 16 described above has better electron emission properties than the chip body 12a, the chip body 12a can be cooled by the cooling effect due to electron emission.

[0039] As shown in FIG. 4(a), a recess 17 is formed at the tip of the chip body 12a. This recess 17 is a disk-shaped depression and serves as a receiving portion for the tungsten ring 16. The insert chip 12 according to the present embodiment is configured by attaching the tungsten ring 16 to the above-described recess 17 as shown in FIG. 4(b).

[0040] As a method for attaching the tungsten ring 16 to the chip body 12a, for example, methods such as brazing, press-fitting, and screwing can be applied. As the brazing material when brazing is performed, for example, silver brazing or copper brazing is used. Note that the method for attaching the tungsten ring 16 to the chip body 12a may be any other method as long as the tungsten ring 16 does not fall off from the chip body 12a during welding and the chip body 12a and the tungsten ring 16 are in close contact with each other.

[0041] Also, as described above, the tungsten ring 16 is a component separate from the chip body 12a and is attached to the chip body 12a as a product. That is, the insert chip 12 according to the present embodiment is different from a casting of an insert chip in which a tungsten ring is embedded, which is obtained by casting, for example, with the tungsten ring set in a mold.

[0042] The inner region of the tungsten ring 16 attached to the tip of the chip body 12a functions as the arc ejection hole 15. Therefore, the arc ejection hole 15 in the present embodiment is constituted by the inner peripheral surface of the tip opening of the chip body 12a and the inner peripheral surface of the tungsten ring 16. In other words, at least a part of the wall surface around the arc ejection hole 15 is constituted by the inner peripheral surface of the tungsten ring 16.

[0043] As shown in FIG. 3, in the present embodiment, the chip body 12a is connected to the negative electrode side of the hot wire power source 41, and the welding wire 21 is connected to the positive electrode side of the hot wire power source 41. That is, similar to the first embodiment described above, also in the plasma welding apparatus 1 according to the present embodiment, the hot wire power source 41 is not connected to the tungsten electrode 11 of the welding torch 10. Therefore, the current flowing through the tungsten electrode 11 can be reduced, and the thermal load on the tungsten electrode 11 during welding can be reduced.

[0044] Incidentally, the temperature of the wall surface around the arc ejection hole 15 during welding rises due to resistive heating caused by the flow of current through the tip body 12a and heat transfer from the plasma arc 3. At this time, if the insert tip 12 has a structure without tungsten ring 16, depending on the material of the tip body 12a and the water-cooling structure of the tip body 12a, the tip of the tip body 12a that forms the wall surface around the arc ejection hole 15 may melt and wear out.

[0045] On the other hand, in the insert tip 12 according to the present embodiment, a tungsten ring 16 having a melting point higher than that of the tip body 12a and good electron emission properties is attached to the tip of the tip body 12a. That is, a tungsten ring 16 having a high melting point and a cooling effect due to electron emission is attached to a location where thermal conditions are severe during welding, thereby suppressing the melting and wear of the wall surface around the arc ejection hole 15. In addition, due to the cooling effect of the electron emission of the tungsten ring 16, it is also possible to cool the tip body 12a in the vicinity of the arc ejection hole 15.

[0046] Furthermore, since the tungsten ring 16 is a member with better electron emission than the tip body 12a, current is more likely to flow through the tungsten ring 16 than through the tip body 12a in the vicinity of the arc ejection hole 15. As a result, it is possible to suppress the resistive heating of the tip body 12a in the vicinity of the arc ejection hole 15 and suppress the temperature rise of the tip body 12a.

[0047] Therefore, by using the insert tip 12 according to the present embodiment, even if there is a risk of melting and wear occurring only in the tip body 12a, the durability of the insert tip 12 against the heat load can be improved, and the melting and wear of the tip of the insert tip can be suppressed.

[0048] In addition, it is also possible to increase the available current within the range where the tungsten ring 16 does not undergo melting loss, and it is possible to increase the amount of welding during build-up welding. Therefore, from the perspective of obtaining these operational effects, it is preferable to attach the tungsten ring 16 to the tip of the chip body 12a.

[0049] Note that in this embodiment, the welding torch 10 in which the hot wire power source 41 is electrically connected to the welding wire 21 and the chip body 12a is exemplified to explain the advantages of providing the tungsten ring 16. However, the effect that the durability against the heat load is improved by attaching the tungsten ring 16 to the tip of the chip body 12a is not an effect that occurs only when the power supply structure in this embodiment is adopted.

[0050] For example, general plasma welding has a problem that the welding speed is slower than that of consumable electrode welding. As one of the countermeasures, there is an increase in the magnitude of the current flowing through the welding torch. However, such an increase in the magnitude of the current will increase the heat load on the tip of the insert chip. In a conventional insert chip without the tungsten ring 16, there is a concern that the tip of the chip will undergo melting loss due to an increase in the amount of resistance heat generation caused by the large current. For this reason, in a conventional insert chip, there is a limitation on the available current during welding, and there is a problem from the perspective of increasing the welding speed of plasma welding.

[0051] The above problems are common problems in general plasma welding apparatuses and are not problems that occur only in the plasma welding apparatus 1 having a structure in which the hot wire power source 41 is connected to the chip body 12a and the welding wire 21. Therefore, it can be said that the invention regarding the insert chip with the tungsten ring 16 attached to the tip of the chip body 12a is also an invention that solves the problems described in the above paragraph. And it can be said that the invention of such an insert chip for a plasma welding torch is an invention that improves the durability against the heat load at the tip of the insert chip during welding and enables an increase in the available current during welding.

[0052] (Other Structural Examples of the Tip of the Insert Chip) Here, other structural examples of the insert chip 12 with a tungsten member attached to the tip of the chip body 12a will be described with reference to FIGS. 5 to 8. Note that FIGS. 5(a), 6(a), and 7(a) show cross-sectional views of the insert chip 12, and FIGS. 5(b), 6(b), and 7(b) show views of the insert chip 12 as seen from the tip side. Also, FIG. 8(a) shows a side view of the insert chip 12, and FIG. 8(b) shows a view of the insert chip 12 as seen from the tip side.

[0053] In the chip body 12a in the example of FIG. 5, a cylindrical wall portion 18 is formed on the tip surface, and an arc ejection hole 15 is formed on the inner peripheral surface of the cylindrical wall portion 18. The tungsten ring 16 in this example is attached to the outside of the cylindrical wall portion 18. More specifically, the inner diameter of the tungsten ring 16 is larger than the outer diameter of the cylindrical wall portion 18, and the inner peripheral surface of the tungsten ring 16 is in contact with the outer peripheral surface of the cylindrical wall portion 18.

[0054] Since the tungsten ring 16 is a member with better electron emission properties than the copper chip body 12a, the chip body 12a can be cooled by the cooling effect due to the electron emission of the tungsten ring 16. Further, in the vicinity of the arc ejection hole 15, current flows preferentially through the tungsten ring 16 rather than the chip body 12a, so that the resistive heating of the chip body 12a can be suppressed.

[0055] Therefore, also in the insert chip 12 as shown in FIG. 5, since the tungsten ring 16 is attached to the tip of the chip body 12a, the temperature rise of the chip body 12a can be suppressed as compared with the case where the insert chip 12 is composed only of the chip body 12a. That is, the effect of suppressing the melting and wear of the tip of the insert chip 12 can be obtained.

[0056] As an example of the structure of the insert chip 12 that can achieve the same effect, there is also a structure shown in FIG. 6, for example. In the example shown in FIG. 6, similar to the example shown in FIG. 5, tungsten ring 16 is attached to the outside of the cylindrical wall portion 18 of the chip body 12a. However, different from the example shown in FIG. 5, the outer peripheral surface of the tungsten ring 16 is not exposed to the outside of the insert chip 12. The tungsten ring 16 is inserted, for example, from an annular groove (not shown) formed on the tip surface of the chip body 12a and fixed to the chip body 12a. Only the lower surface (the surface on the chip tip side) of the tungsten ring 16 is exposed to the outside of the insert chip 12. Even in the insert chip 12 having such a structure, the effect of suppressing the melting loss of the tip portion can be obtained.

[0057] In the above description, the annular tungsten ring 16 is exemplified as the tungsten member attached to the tip portion of the chip body 12a. However, the tungsten member is not limited to an annular shape. For example, as shown in FIG. 7, the tungsten member may be a rod-shaped tungsten bar 19 extending toward the tip side of the chip body 12a on the side of the arc ejection hole 15.

[0058] In this example, as shown in FIG. 7(a), a plurality of tungsten bars 19 are provided, and each tungsten bar 19 is arranged so as to be parallel to the central axis (the dashed-dotted line in the figure) of the insert chip 12. Further, as shown in FIG. 7(b), the plurality of tungsten bars 19 are arranged at intervals in the circumferential direction of the arc ejection hole 15. For example, the plurality of tungsten bars 19 are arranged at equal intervals along the circumferential direction of the arc ejection hole 15, and are arranged such that the center of the circle passing through the center of each tungsten bar 19 when viewed from the tip side of the chip body 12a coincides with the center of the arc ejection hole 15.

[0059] For example, as shown in FIG. 8, the tungsten rod 19 may be attached to the tapered surface at the tip of the chip body 12a. Also in the example shown in FIG. 8, each tungsten rod 19 is arranged so as to extend toward the tip side of the chip body 12a. As shown in FIG. 8(b), when viewed from the tip side of the chip body 12a, the tungsten rods 19 are arranged at intervals in the circumferential direction of the arc ejection holes 15. Further, as shown in FIG. 8(b), the tungsten rods 19 are arranged radially such that, when the chip body 12a is viewed from the tip side, the extension lines of the tungsten rods 19 intersect at the center of the arc ejection holes 15.

[0060] Even in the insert chip 12 having the structures as shown in FIGS. 7 and 8 above, the effect of suppressing the melting and wear at the tip can be obtained. Note that the tungsten rod 19, which is an example of the rod-shaped member, may be a round rod or a square rod.

[0061] In the above description, a plurality of structural examples of the insert chip 12 are shown. However, from the viewpoint of suppressing the melting and wear at the tip of the insert chip 12, it is most preferable that the inner peripheral surface of the arc ejection hole 15, which will be in continuous contact with the arc during arc generation, be formed of a tungsten ring 16 as shown in FIG. 4.

[0062] Also, in the above description, a tungsten member (tungsten ring 16 or tungsten rod 19) is exemplified as a member having a melting point higher than that of the chip body 12a and good electron emissivity. However, the member having a melting point higher than that of the chip body 12a and good electron emissivity is not limited to the above-mentioned tungsten member.

[0063] <Third Embodiment> Next, the plasma welding apparatus 1 according to the third embodiment will be described. The plasma welding apparatus 1 according to the third embodiment has the same configuration as the plasma welding apparatus 1 according to the first embodiment, except that a plurality of welding wires 21 can be fed toward the tip of the welding torch 10.

[0064] In FIG. 9, a plasma welding apparatus 1 that feeds two welding wires 21a and 21b is illustrated. In this example, a first wire nozzle 33a and a second wire nozzle 33b are provided as wire nozzles 33 that feed the welding wire 21. Also, a first hot wire power source 41a for heating a first welding wire 21a passing through the inside of the first wire nozzle 33a and a second hot wire power source 41b for heating a second welding wire 21b passing through the inside of the second wire nozzle 33b are also provided.

[0065] And both of the two hot wire power sources 41a and 41b are connected to the insert chip 12 instead of the tungsten electrode 11. For this reason, also in the plasma welding apparatus 1 shown in FIG. 9, compared with the conventional apparatus in which the hot wire power source is connected to the tungsten electrode 11, the thermal load on the tungsten electrode 11 during welding can be reduced.

[0066] Note that, as shown in FIG. 10, also in the plasma welding apparatus 1 capable of feeding a plurality of welding wires 21a and 21b, a tungsten ring 16 may be attached to the tip of the chip body 12a. Thereby, the durability against the thermal load at the tip of the insert chip 12 is improved, and the melting loss at the tip of the insert chip 12 during welding can be suppressed. In a structure in which a plurality of hot wire power sources 41a and 41b are connected to the insert chip 12, since the amount of heat generated by resistance increases as the current flowing through the insert chip 12 increases, it is particularly useful to attach the tungsten ring 16 to the chip body 12a.

[0067] Next, an example of the arrangement of the wire nozzles 33 when feeding a plurality of welding wires 21 will be described with reference to FIGS. 11 to 14. Note that FIGS. 11 to 14 illustrate the arrangement of the wire nozzles 33 when viewed from the tip side of the welding torch 10.

[0068] (Arrangement example of two wire nozzles) In the example shown in FIG. 11, two wire nozzles 33a and 33b are provided. These first wire nozzle 33a and second wire nozzle 33b are arranged to face each other with the center 15a of the arc ejection hole of the welding torch interposed therebetween. More specifically, the center lines of the two wire nozzles 33a and 33b are on the same straight line and pass through the center 15a of the arc ejection hole.

[0069] As described in the foregoing first embodiment, when the welding wire 21 is connected to the positive electrode side of the hot wire power source 41, the direction of the electromagnetic force acting on the molten droplet becomes a direction approaching the center side of the plasma arc 3. On the other hand, when only one welding wire 21 is fed, when an excessive electromagnetic force acts on the molten droplet, the scattered molten droplet may pass through the center of the plasma arc 3 and fall as spatter outside the molten pool of the base material 2.

[0070] In contrast, when two wire nozzles 33a and 33b are arranged to face each other as shown in FIG. 11, the direction of the electromagnetic force generated by energizing the welding wire 21a passing through the first wire nozzle 33a and the direction of the electromagnetic force generated by energizing the welding wire 21b passing through the second wire nozzle 33b are opposite to each other. That is, the electromagnetic forces directed toward the center of the plasma arc generated by energizing each of the welding wires 21a and 21b cancel each other out at the center of the plasma arc.

[0071] As a result, the molten droplets of the first welding wire 21a and the molten droplets of the second welding wire 21b scatter in the direction toward the center of the plasma arc, respectively, but for each molten droplet, an electromagnetic force sufficient to scatter through the center of the plasma arc to the outside of the plasma arc does not act. For this reason, the molten droplets of each of the welding wires 21a and 21b are likely to fall into the molten pool of the base material.

[0072] Furthermore, the cancellation of electromagnetic forces also has the effect of suppressing the bending of the arc due to electromagnetic forces (arc deflection by magnetic blow). When the electromagnetic forces are cancelled out, the shape of the arc becomes a straight line along the extension line of the central axis of the welding torch. As a result, a stable welding bead can be formed directly below the arc, and a highly reproducible welding result can be obtained. Therefore, from the viewpoint of suppressing spatter adhesion to the welded product and improving the welding quality, it is preferable to arrange a plurality of wire nozzles 33 so as to face each other.

[0073] (Arrangement example of three wire nozzles) In FIG. 12, an example in which three wire nozzles 33a to 33c are arranged is shown. In this example, the wire nozzles 33a to 33c are arranged such that the angles formed by the center lines of the first wire nozzle 33a, the second wire nozzle 33b, and the third wire nozzle 33c are all equal. Even when the wire nozzles 33a to 33c are arranged in this way, the spatter suppression effect and the arc bending suppression effect due to the cancellation of electromagnetic forces can be obtained in the same manner as in the case of the arrangement example of the two wire nozzles described above.

[0074] (Arrangement example of four wire nozzles) In FIG. 13, an example in which four wire nozzles 33a to 33d are arranged is shown. In this example, the first wire nozzle 33a and the second wire nozzle 33b are arranged to face each other in the same manner as in FIG. 11, and further, the third wire nozzle 33c and the fourth wire nozzle 33d are also arranged to face each other with the center 15a of the arc ejection hole in between. Also, the wire nozzles 33a to 33d are arranged such that the angle A formed by the center line of the first wire nozzle 33a and the center line of the third wire nozzle 33c is equal to the angle B formed by the center line of the second wire nozzle 33b and the center line of the fourth wire nozzle 33d.

[0075] Such an arrangement of the wire nozzles 33a to 33d is also a preferable arrangement from the viewpoint that the cancellation of electromagnetic forces occurs. Further, an arrangement in which the above angles A and B are 90°, that is, an arrangement in which the angles formed by the center lines of two adjacent wire nozzles in the circumferential direction are all equal as shown in FIG. 14 is an even more preferable arrangement.

[0076] As described above, as embodiments of the present invention, the first to third embodiments have been illustrated and described by way of example.

[0077] In the first to third embodiments, a plasma welding apparatus is cited as an example of a non-consumable electrode type welding apparatus. However, the non-consumable electrode type welding apparatus may be, for example, a TIG welding apparatus. In the case of a TIG welding apparatus, for example, a hot wire power source is connected to a nozzle composed of a conductor disposed around a tungsten electrode and a welding wire, whereby the heat load on the tungsten electrode can be reduced.

[0078] That is, from the viewpoint of reducing the heat load on the non-consumable electrode, the hot wire power source may have a configuration in which a power supply unit for heating the welding wire is electrically connected to a conductor disposed at a distance from the non-consumable electrode around the non-consumable electrode.

[0079] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to such examples. It is obvious that those skilled in the art can conceive of various modification examples or correction examples within the scope of the technical idea described in the claims, and it is naturally understood that those also belong to the technical scope of the present invention.

[0080] For example, the constituent elements of the above embodiments can be arbitrarily combined. From such an arbitrary combination, the actions and effects of each constituent element related to the combination can be naturally obtained, and other actions and other effects obvious to those skilled in the art from the description of this specification can be obtained.

[0081] In addition, the effects described in this specification are merely illustrative or exemplary and not restrictive. That is, the technology according to the present disclosure can exhibit other effects obvious to those skilled in the art from the description of this specification together with or instead of the above effects.

[0082] Note that the following configuration examples also belong to the technical scope of the present disclosure. (1) A non-consumable electrode type welding apparatus that performs welding by the hot wire method, a welding torch, a power supply unit that supplies power to a welding wire fed between the welding torch and a base material, a first power source for generating an arc between the welding torch and the base material, and a second power source for heating the welding wire, and is provided with, the welding torch has a non-consumable electrode, and a conductor disposed at a distance from the non-consumable electrode around the non-consumable electrode, the first power source has a configuration electrically connected to the base material and the non-consumable electrode, the second power source has a configuration electrically connected to the power supply unit and the conductor, a non-consumable electrode type welding apparatus. (2) The welding torch is a torch for plasma welding, the conductor is an insert chip attached to the tip of the welding torch, the non-consumable electrode type welding apparatus according to (1). (3) The insert chip has a chip body made of a conductor, an arc ejection hole from which the arc ejects, and a member made of a material having a higher melting point and better electron emissivity than the chip body, attached to the tip of the chip body, the non-consumable electrode type welding apparatus according to (2). (4) The member is an annular member, the arc ejection hole is located inside the annular member, the non-consumable electrode type welding apparatus according to (3). (5) At least a part of the wall surface around the arc ejection hole is constituted by the inner peripheral surface of the annular member, the non-consumable electrode type welding apparatus according to (4). (6) The member is a rod-shaped member extending toward the tip side of the chip body on the side of the arc ejection hole, The non-consumable electrode type welding apparatus according to (3), characterized in that a plurality of the rod-shaped members are provided at intervals in the circumferential direction of the arc ejection holes when viewed from the tip side of the chip body. (7) The power supply unit is connected to the positive electrode side of the second power source, The non-consumable electrode type welding apparatus according to any one of (1) to (6), characterized in that the conductor is connected to the negative electrode side of the second power source. (8) It has two wire nozzles for feeding the welding wire to the tip of the welding torch, When the welding torch is viewed from the tip side of the welding torch, the first wire nozzle and the second wire nozzle are arranged to face each other with the center of the arc ejection hole of the welding torch interposed therebetween. The non-consumable electrode type welding apparatus according to any one of (1) to (7). (9) It has three wire nozzles for feeding the welding wire to the tip of the welding torch, When the welding torch is viewed from the tip side of the welding torch, the angles formed by the center lines of the respective wire nozzles are all equal. The non-consumable electrode type welding apparatus according to any one of (1) to (7). (10) It further has two wire nozzles, When the welding torch is viewed from the tip side of the welding torch, The third wire nozzle and the fourth wire nozzle are arranged to face each other with the center of the arc ejection hole of the welding torch interposed therebetween, The non-consumable electrode type welding apparatus according to (8), characterized in that an angle A formed by the center line of the first wire nozzle and the center line of the third wire nozzle and an angle B formed by the center line of the second wire nozzle and the center line of the fourth wire nozzle are equal to each other. (11) The non-consumable electrode type welding apparatus according to (10), characterized in that the angle A and the angle B are 90°.

Industrial Applicability

[0083] The present invention can be applied to a non-consumable electrode type welding apparatus of a hot wire method.

Explanation of Signs

[0084] 1 Plasma welding device 2 Base material 3 Plasma arc 10 Welding torch 11 Tungsten electrode 12 Insert chip 12a Chip body 13 Shield cap 14 Cooling water flow path 15 Arc ejection hole 16 Tungsten ring 17 Recess 18 Cylindrical wall portion 19 Tungsten rod 20 Wire feeder 21 Welding wire 21a - 21d Welding wire 22 Wire spool 23 Feeding roller 24 Motor 30 Wire feeding path 31 Housing 32 Consit liner 33 Wire nozzle 33a - 33d Wire nozzle 34 Power supply electrode 40 Plasma welding power source 41 Hot wire power source 41a, 41b Hot wire power source

Claims

1. A non-consumable electrode type welding apparatus that performs welding by the hot wire method, comprising: a welding torch; a power supply unit that supplies power to a welding wire fed between the welding torch and a base material; a first power source for generating an arc between the welding torch and the base material; a second power source for heating the welding wire, wherein the welding torch has a non-consumable electrode, and a conductor disposed at a distance from the non-consumable electrode around the non-consumable electrode, the first power source is configured to be electrically connected to the base material and the non-consumable electrode, and the second power source is configured to be electrically connected to the power supply unit and the conductor. A non-consumable electrode type welding apparatus characterized by this.

2. The welding torch is a torch for plasma welding, and the conductor is an insert chip attached to the tip of the welding torch. The non-consumable electrode type welding apparatus according to claim 1, characterized by this.

3. The insert chip has a chip body made of a conductor, an arc ejection hole through which the arc ejects, and a member made of a material having a melting point higher than that of the chip body and good electron emission property, attached to the tip of the chip body. The non-consumable electrode type welding apparatus according to claim 2, characterized by this.

4. The member is an annular member, and the arc ejection hole is located inside the annular member. The non-consumable electrode type welding apparatus according to claim 3, characterized by this.

5. At least a part of the wall surface around the arc ejection hole is constituted by the inner peripheral surface of the annular member. The non-consumable electrode type welding apparatus according to claim 4, characterized by this.

6. The member is a rod-shaped member extending toward the tip side of the chip body on the side of the arc ejection hole, and a plurality of the rod-shaped members are provided at intervals in the circumferential direction of the arc ejection hole when viewed from the tip side of the chip body. The non-consumable electrode type welding apparatus according to claim 3, characterized by this.

7. The power supply unit is connected to the positive electrode side of the second power source, and the conductor is connected to the negative electrode side of the second power source. The non-consumable electrode type welding apparatus according to any one of claims 1 to 6, characterized by this.

8. It has two wire nozzles for feeding the welding wire to the tip of the welding torch, The non-consumable electrode type welding apparatus according to any one of claims 1 to 6, wherein when the welding torch is viewed from the tip side of the welding torch, the first wire nozzle and the second wire nozzle are arranged to face each other with the center of the arc ejection hole of the welding torch therebetween.

9. having three wire nozzles for feeding the welding wire to the tip of the welding torch, The non-consumable electrode type welding apparatus according to any one of claims 1 to 6, wherein when the welding torch is viewed from the tip side of the welding torch, all the angles formed by the center lines of the respective wire nozzles are equal.

10. further having two wire nozzles, when the welding torch is viewed from the tip side of the welding torch, the third wire nozzle and the fourth wire nozzle are arranged to face each other with the center of the arc ejection hole of the welding torch therebetween, The non-consumable electrode type welding apparatus according to claim 8, wherein an angle A formed by the center line of the first wire nozzle and the center line of the third wire nozzle and an angle B formed by the center line of the second wire nozzle and the center line of the fourth wire nozzle are equal to each other.

11. The non-consumable electrode type welding apparatus according to claim 10, wherein the angle A and the angle B are 90°.

12. A non-consumable electrode type welding method for performing hot wire welding, a non-consumable electrode, using a welding torch having a conductor arranged at a distance from the non-consumable electrode around the non-consumable electrode, energizing between the base material and the non-consumable electrode with a first power source to generate an arc, A non-consumable electrode type welding method characterized in that welding is performed by energizing between the welding wire and the conductor with a second power source to heat the welding wire.

13. the welding torch is a torch for plasma welding, The non-consumable electrode type welding method according to claim 12, wherein the conductor is an insert chip attached to the tip of the welding torch.

14. The insert chip is a chip body made of a conductor, an arc ejection hole from which the arc ejects, The non-consumable electrode type welding method according to claim 13, further comprising a member made of a material having a melting point higher than that of the chip body and good electron emission property, attached to the tip of the chip body.

15. the member is an annular member, The non-consumable electrode type welding method according to claim 14, wherein the arc ejection hole is located inside the annular member.

16. The non-consumable electrode type welding method according to claim 15, wherein at least a part of the wall surface around the arc ejection hole is constituted by the inner peripheral surface of the annular member.

17. The member is a rod-shaped member extending toward the tip side of the tip body on the side of the arc ejection hole, The non-consumable electrode type welding method according to claim 14, wherein a plurality of the rod-shaped members are provided at intervals in the circumferential direction of the arc ejection hole when viewed from the tip side of the tip body.

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