JP5441156B2 - Insert tip, plasma torch and plasma processing equipment - Google Patents

Description

  The present invention relates to an insert tip of a plasma torch, a plasma torch using the insert tip, and a plasma processing apparatus using the plasma torch.

  There are various types of plasma torches depending on the type of high heat processing such as welding, overlaying and cutting. In Patent Document 1, a wire 16 is fed from the side just below the tip of the electrode rod 10, and the base material (material to be processed) below the tip of the electrode rod is plasma welded, plasma welding in the form of a hot wire, or plasma MIG. A method of welding or plasma wire overlaying is described. In Patent Document 2, a wire 153 is fed vertically from a central wire feed hole of an insert tip 111 to a lower base material, and an electrode rod 126 arranged in parallel to the wire on the side of the wire, A plasma MIG welding torch is described in which plasma is injected into a plasma hole 113 at the bottom where the wire passage hole is opened to melt the wire tip. Patent Document 3 describes a hot-wire-type plasma welding method and a plasma wire build-up method in which a wire 3 is fed from the side below a plasma nozzle of an insert tip 1 in which an electrode rod is arranged at the center position. In Patent Document 4, plasma MIG welding in which a wire 39 as a consumable electrode is fed from the side of the plasma torch toward a pool formed by plasma of a plasma torch in which an electrode rod is disposed at the center position of the insert tip 33. Is described. In Patent Document 5, a bottom base material that is a center hole of a bottomed cylindrical plasma electrode 8 disposed above and in the center of a plasma injection nozzle of an insert tip 9 and a lower base material through a nozzle plasma injection nozzle below the center hole. Describes a plasma MIG welding method in which a wire is fed perpendicularly and the wire is melted by plasma generated by a plasma electrode 8.

Japanese Examined Patent Publication No. 39-15267 JP 52-138038 A JP-A-53-31544 JP-T-2006-519103 JP 2008-229641 A.

  In any of the welding methods and plasma torches of Patent Documents 1 to 4, an electrode rod / base material is formed into a plasma flow formed between the electrode rod and a base material using one electrode bar and a single wire. Since the wires are fed and energized from the sides between them, magnetic imbalance occurs due to the interaction between the magnetic flux generated by the wire current and the magnetic flux generated by the plasma current. That is, the plasma arc state is different between the upper side of the wire (insert chip side) and the lower side of the wire (base metal side), and the plasma on the upper side of the wire receives an arc force in a direction away from the wire, The plasma receives an arc force in a direction approaching the wire. The plasma arc is unstable because the plasma action position on the base material fluctuates as the wire tip melts. In Patent Document 5, since the arc concentrates on the circumferential edge of the bottom hole of the bottomed cylindrical plasma electrode 8 and the concentration point moves in the circumferential direction, the plasma is still shaken, and the bottom hole of the plasma electrode 8 is circled. The peripheral edge and the nozzle edge of the insert tip 9 are worn and the molten wire adheres to the plasma electrode 8 and the plasma nozzle 9 so that stable welding cannot be maintained for a long time.

  The present invention provides an insert tip having high stability that does not cause arc turbulence due to magnetic blowing even in a method of supplying electricity to a wire by supplying a molten material to a plasma arc and a coaxial central portion with high efficiency and good workability. The second object is to provide a plasma torch and a plasma processing apparatus with high plasma stability.

(1) A central hole (5), which is a through hole, and a plasma gas distributed at an equiangular pitch parallel to the central hole (5) or on a circumference centered on the central axis of the central hole with a certain inclination angle There plurality of electrodes disposed space (1a, 1b) that will be supplied, communicates with the electrode arrangement space (1a, 1b), a plurality of nozzles which are distributed at equal angular pitch on a circumference around the central axis ( 4a, 4b), and an insert tip comprising:
Each nozzle of the plurality of nozzles (4a, 4b) is processed with each electrode (2a, 2b) inserted into the electrode arrangement space (1a, 1b) with respect to the central axis of the central hole (5) Each plasma arc current flowing between the material (16) through the plurality of nozzles (4a, 4b) is inclined at an angle at which the insert tip joins before and after the tip surface facing the workpiece (16). Insert tip (1).

  In addition, in order to make an understanding easy, the code | symbol of the corresponding element or the equivalent element of the Example which is shown in drawing and mentions later in parentheses is attached for reference by reference. The same applies to the following.

  According to this, it passes between each electrode (2a, 2b) inserted in electrode arrangement space (1a, 1b) and a workpiece (16) through each nozzle (4a, 4b: FIG. 5). Since the upper portions of the magnetic fluxes Ma and Mb induced by each arc current cancel each other, the lower portion acts and an upward force expressed by Fleming's left-hand rule acts, and the arcs attract each other. It becomes a symmetric shape with a slightly bent shape upward. Moreover, due to the equiangular pitch distribution on the circumference of the nozzle (4a, 4b) centered on the central axis of the central hole (5), each force is also a circumference centered on the central axis of the central hole (5). Since it is distributed at an equiangular pitch, the stability of the plasma is high. That is, no arc wobbling due to magnetic blowing occurs. In the vicinity of the material to be processed (16), each arc current is added in the same direction and induces the composite magnetic flux Mc, so that the magnetic pinch force for constricting the arc is strong and the heat convergence effect (energy) on the material to be processed (16) Density) and the working position does not fluctuate.

It is a longitudinal cross-sectional view of the plasma torch of the first embodiment of the present invention. (A) is a longitudinal cross-sectional view which shows only the plasma torch of FIG. 1, (b) is the bottom view seen from the plasma injection end part side. 1 is an enlarged view of the insert chip 1 shown in FIG. 1, wherein (a) is a front view, (b) is a longitudinal sectional view taken along line 2b-2b in (c), and (c) is a bottom view. 1 shows a cooling water passage 9w, a pilot gas passage 9p, and a shield gas passage 9s of the plasma torch shown in FIG. 1, wherein (a) is a longitudinal sectional view showing the cooling water passage 9w, and (b) is a longitudinal sectional view showing the pilot gas passage 9p. (C) is a longitudinal sectional view taken along line 4b-4b, (c) is a transverse sectional view taken along line 4c-4c, and (d) is a longitudinal sectional view showing shield gas passage 9s. (E) is a longitudinal sectional view taken along line 4d-4d, and (e) is a transverse sectional view taken along line 4e-4e in (d). FIG. 4 is an enlarged longitudinal sectional view of the insert tip 1 corresponding to FIG. 3B, and shows magnetic fluxes Ma and Mb and composite magnetic flux Mc induced by arcs generated by the first electrode 2 a and the second electrode 2 b. Show. It is a longitudinal cross-sectional view of the plasma torch of the second embodiment of the present invention. It is a longitudinal cross-sectional view of the plasma torch of the 3rd example of the present invention. It is a longitudinal cross-sectional view of the plasma torch of the 4th example of the present invention. It is a longitudinal cross-sectional view of the plasma torch of 5th Example of this invention. It is a longitudinal cross-sectional view of the plasma torch of 6th Example of this invention. It is a longitudinal cross-sectional view of the plasma torch of the seventh embodiment of the present invention.

(2) insert the chip (1) further, the central opening (5) to continuously open to the front end face the central opening (5) larger port cone shape flared diameter larger than (1d), the The insert tip according to claim 1, wherein the nozzle (4a, 4b) is open to the enlarged opening (1d) inside the tip end surface.

  According to this, each arc current flowing between each electrode (2a, 2b) inserted into the electrode arrangement space (1a, 1b) and the material to be processed (16) becomes the tip surface of the insert tip (expansion port 1d). Since the plasma arcs can be joined at a distance close to the shortest distance, the change in arc bending due to mutual magnetic interference can be reduced, and the machining accuracy is improved with a stable arc.

  (3) The insert tip (1) according to (1) or (2) above, and a wire guide (13, 6) for guiding the wire (15) into the central hole (5) of the insert tip (1) A plurality of electrodes (2a, 2b) having tips inserted into the electrode arrangement spaces (1a, 1b) of the insert tip (1), and a cooling water channel (9w) for cooling the insert tip (1) And a pilot gas channel (9p) for supplying pilot gas to each electrode arrangement space (1a, 1b) (FIG. 2).

  (4) A power source for passing a plasma arc current between the plasma torch described in (3) above and the plurality of electrodes (2a, 2b) and the workpiece (16) with a negative electrode side and a positive workpiece arc side (17, 18) and a plasma welding apparatus (FIG. 1).

  (5) Furthermore, a hot wire power source (21) is provided between the wire (15) and the material to be processed (16), and the wire side is negative and the material to be processed side supplies a positive current. The plasma welding apparatus of a hot wire form (FIG. 6).

  (6) A power supply for passing a plasma arc current between the plasma torch described in (3) above and the plurality of electrodes (2a, 2b) and the workpiece (16) with a positive electrode side and a negative workpiece side A plasma MIG welding apparatus comprising a MIG welding power source (22) between the wires (17, 18) and the wire (15) and the material to be processed (16) for flowing a positive current on the wire side and a negative current on the material to be processed side (FIG. 7).

  (7) A power source for passing a plasma arc current between the plasma torch described in (3) above and the plurality of electrodes (2a, 2b) and the workpiece (16) with a negative electrode side and a positive workpiece arc side (17, 18), and a hot wire power source (21a, 21b) for passing a current that is positive on the wire side and negative on the electrode side, between the wire (15) and each electrode (2a, 2b). Assembling device (FIG. 8).

  (8) The insert tip (1) according to (1) or (2) above, and a powder guide (6) for guiding the powder (23) to the central hole (5) of the insert tip (1) A plurality of electrodes (2a, 2b) having tips inserted into the electrode arrangement spaces (1a, 1b) of the insert tip (1), and a cooling water channel (9w) for cooling the insert tip (1) And a pilot gas flow path (9p) for supplying pilot gas to each electrode arrangement space (1a, 1b) (FIG. 9).

  (9) The plasma powder build-up torch according to (8) above and a plasma arc between the plurality of electrodes (2a, 2b) and the workpiece (16) having a negative electrode side and a positive workpiece side A plasma powder overlaying apparatus (FIG. 9) comprising a power source (17, 18) for supplying an electric current and means (24, 25) for feeding powder to the powder guide (6).

  (10) The insert tip (1) according to (1) or (2) above, and a gas guide (6) for guiding the keyhole gas (26) to the central hole (5) of the insert tip (1) A plurality of electrodes (2a, 2b) having tips inserted into the electrode arrangement spaces (1a, 1b) of the insert tip (1), and a cooling water channel (9w) for cooling the insert tip (1) And a pilot gas flow path (9p) for supplying pilot gas to each electrode arrangement space (1a, 1b) (FIG. 10).

  (11) Between the plasma keyhole welding torch according to (10) above and the plurality of electrodes (2a, 2b) and the workpiece (16), the plasma arc current is negative on the electrode side and positive on the workpiece side And a plasma keyhole welding device (FIG. 10).

  (12) The insert tip (1) according to (1) or (2) above, a gas guide (6) for guiding the cutting gas (27) to the central hole (5) of the insert tip (1), A plurality of electrodes (2a, 2b) having tips inserted into each electrode arrangement space (1a, 1b) of the insert tip (1), and a cooling water flow path (9w) for cooling the insert tip (1) A plasma cutting torch (FIG. 11) comprising a pilot gas flow path (9p) for supplying pilot gas to each electrode arrangement space (1a, 1b).

  (13) Between the plasma cutting torch according to (12) above and the plurality of electrodes (2a, 2b) and the workpiece (16), a negative plasma arc current and a positive plasma arc current on the workpiece side are passed. And a plasma cutting device (FIG. 11).

  In any of the above aspects (3) to (13), the effect (1), that is, the “effect of the invention” can be obtained.

  Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

-1st Example-
FIG. 1 shows a plasma welding apparatus according to the first embodiment, FIG. 2 (a) shows only the plasma torch shown in FIG. 1, ie, the plasma welding torch of the first embodiment, and FIG. Indicates the tip of the torch. The plasma welding torch according to the first embodiment is configured to perform plasma welding. The insert chip 1 is fixed to the insulating base 9 by screwing the insert cap 7 to the insulating base 9. The shield cap 8 is fixed to the insulating table 9 by screwing. The first electrode 11 and the second electrode 12 ((c) and (e) of FIG. 4) separated in the x direction by being divided into two are inside an outer case 30 made of an insulator. The space between the first electrode 11 and the second electrode 12 is passed through the hollow cylindrical stem of the insulating body 14, and the male screw (not shown) at the tip of the stem is at the center of the insulating base 9. Screwed into a female screw hole (not shown), the electrode bases 11 and 12 are tightened so as to be compressed in the vertical direction, and the insulating base 9, the electrode bases 11 and 12 and the insulating main body 14 are integrally coupled. Yes.

  There is a central hole 5 in the axial center of the insert chip 1, and there are guide holes (wire guide holes in this embodiment) coaxial with the central hole 5 in the axial centers of the insulating base 9 and the insulating body 14. A wire guide 6 is inserted into the central hole 5 of the insert chip 1, and a wire guide 13 is also inserted into a guide hole in the axial center of the insulating body 14. The welding wire 15 inserted into the head of the insulating body 14 is fed into the insert tip 1 through the wire guides 13 and 6.

  The insert chip 1 has two electrode arrangement spaces 1a and 1b that are distributed at an equiangular pitch of 180 degrees on the circumference centered on the central axis of the central hole 5 and are positioned parallel to the central hole 5. The tip portions of the first electrode 2a and the second electrode 2b that pass through the insulating table 9 and are fixed to the electrode tables 11 and 12 with screws 10a and 10b are inserted into the electrode arrangement spaces, respectively. The centering stone 3 is positioned at the center position. The tip of the insert tip 1 facing the base material 16 is concentric with the central hole 5 but has an enlarged opening 1d having a diameter larger than that of the central hole 5 and connected to the electrode arrangement spaces 1a and 1b. 4 (4a, 4b) is open to the large-diameter opening 1d.

  FIG. 3 shows the insert chip 1 in an enlarged manner. The insert tip 1 of the present embodiment includes a central hole 5 that is a through-hole, and an enlarged opening 1d that has a diameter larger than that of the central hole 5 that is continuous with the central hole 5 and that is open at the front end surface facing the base material 16. The two electrode arrangement spaces 1a and 1b, which are distributed at a pitch of 180 degrees on the circumference centered on the central axis of the central hole 5 and are located in parallel with the central hole 5, and communicate with the electrode arrangement spaces 1a and 1b. And two nozzles 4a and 4b distributed at a pitch of 180 degrees on the circumference centered on the central axis of the central hole 5 opened to the enlarged opening 1d, and the nozzles 4a and 4b are insert tips. 1 is open to the enlargement port 1d on the inner side of the tip surface facing the base material 16.

  In this embodiment, the insert tip of the plasma torch equipped with a pair (two) of electrodes 2a and 2b is used. However, in the insert tip of the plasma torch using a plurality of electrodes such as three or four, A plurality of electrode arrangement spaces distributed in equiangular pitches on the circumference centered on the central axis of the hole 5 and located parallel to the central hole 5; A plurality of nozzles distributed at equiangular pitches on a circumference centered on the central axis of the central hole 5 are provided. For example, an insert tip of a plasma torch having three electrodes has three electrode arrangement spaces that are distributed in parallel with the central hole 5 and distributed at a pitch of 120 degrees on the circumference centered on the central axis of the central hole 5. Three nozzles distributed at a 120-degree pitch are provided on the circumference centering on the central axis of the central hole 5 that communicates with each electrode arrangement space and opens at the expansion port 1d. In addition, the insert tip of the plasma torch having four electrodes is distributed on the circumference centered on the central axis of the central hole 5 at a 90-degree pitch, and four electrode arrangement spaces located in parallel with the central hole 5. And four nozzles distributed in a 90-degree pitch on the circumference centered on the central axis of the central hole 5 that communicates with each electrode arrangement space and opens in the expansion port 1d.

  Moreover, the enlarged opening 1d can be omitted, and the lower end opening of the center hole 5 and the nozzle nozzles 4a and 4b can be used as the flat lower end surface of the chip 1. In addition, the electrode arrangement spaces 1 a and 1 b (and the electrodes 2 a and 2 b provided therein) can be not only parallel to the central hole 5 but also in an oblique posture with a certain inclination angle with respect to the central hole 5.

  FIG. 4 shows a cooling water passage 9w, a pilot gas passage 9p, and a shield gas passage 9s of the plasma torch shown in FIG. The cooling water enters the space between the outer peripheral surface of the insert tip 1 and the inner peripheral surface of the insert cap 7 through the cooling water supply channel 9wi shown in FIG. Go out of the torch through road 9wo. One pilot gas enters the electrode arrangement space 1a through the gas flow path 9pa and the electrode insertion space shown in FIGS. 4B and 4C, becomes plasma at the tip of the electrode, passes through the nozzle 4a, and expands. It ejects from the front end surface of the torch through the mouth 1d. The other pilot gas enters the electrode arrangement space 1b through the gas flow path 9pb and the electrode insertion space, becomes plasma at the electrode tip, passes through the nozzle 4b, and is ejected from the tip of the torch through the expansion port 1d. . The shield gas enters the cylindrical space between the insert cap 7 and the shield cap 8 through the shield gas flow path 9s shown in FIGS. 4D and 4E, and is ejected from the tip of the torch. .

  As shown in FIG. 1, when an arc is generated between the electrodes 2a, 2b and the base material 16 by the plasma power sources 17, 18 that flow a plasma arc current that is negative on the electrode side and positive on the base material side, A plasma arc current flows between each electrode 2a, 2b and the base material 16, and 1 pool 2 arc welding is implement | achieved. Since the wire 15 is fed to the plasma arc 19 and the electrodes 2a and 2b and the nozzles 4 (4a and 4b) are positioned symmetrically with respect to the wire 15, the plasma is stabilized with respect to the wire 15. That is, referring to FIG. 5, each arc current flowing through each nozzle 4a, 4b is induced between each electrode 2a, 2b inserted in the electrode arrangement space 1a, 1b and the base material 16, respectively. The upward (or downward: z) force expressed by Fleming's left-hand rule acts between the magnetic fluxes Ma and Mb, and they are in the same direction, and the central axis of the central hole 5 of the nozzles 4a and 4b. Due to the distribution of equiangular pitches on the circumference centered at the center, each force is also distributed at equiangular pitches on the circumference centered on the central axis of the central hole 5, so that the magnetic balance is achieved, High stability. That is, no arc wobbling due to magnetic blowing occurs. In the vicinity of the base material 16, each arc current is added in the same direction to induce the composite magnetic flux Mc, so that the magnetic pinch force for constricting the arc is strong, the heat convergence effect (energy density) on the base material 16 is high, and the action The position does not fluctuate. In addition, the wire 15 receives heat from the arc until it enters from the upper end of the plasma arc 19 and reaches the molten pool 20, which acts as an effective preheating effect, increases the welding efficiency of the wire, and high-speed welding. And high-efficiency welding. In the case of the conventional wire feeding from the side, since the wire enters almost at right angles to the plasma arc, it must be melted into the molten pool at a short distance from the plasma arc. There is no preheating effect. For this reason, the welding efficiency is low and the welding speed is also slow.

  In addition, according to the first embodiment, since the wire is inserted from the center, there is no insertion directionality of the wire, and control for rotating the torch is not necessary even in curve welding. Conventionally, since the wire is inserted from the direction of travel of the torch, a device for controlling the rotation of the torch or the wire relative to the curve is necessary during curve welding.

-Second Example-
FIG. 6 shows a plasma welding apparatus in the form of a hot wire, which is a second embodiment. The plasma torch is a hot wire type plasma welding torch having the same structure as that of the first embodiment, and the insert tip 1 has the same configuration as that of the first embodiment shown in FIG. In this embodiment, as shown in FIG. 6, plasma power sources 17 and 18 are provided between the electrodes 2 a and 2 b and the base material 16 to flow a plasma arc current that is negative on the electrode side and positive on the base material side. Although this point is the same as that of the first embodiment, a hot wire power source 21 is further provided between the wire 15 and the base material 16 to flow a current that is negative on the wire side and positive on the base material side. The electric current from the hot wire power source 21 passes through the guide 13 in the torch, and the wire is energized from the vicinity of the tip of the guide 13, the wire is heated by Joule heat in the insulating guide 6, and the plasma 19 generates the current from the electrodes 2 a and 2 b. It merges with the plasma arc and flows into the base material 16. At this time, since the Joule heat of the hot wire current is maximized (concentrated) in the plasma region, the welding heat input is large, the welding amount is high, the efficiency is high, and high-speed welding is possible. In addition, since the hot wire current and the plasma arc current from the electrodes 2a and 2b are symmetrical and coaxial, the magnetic balance is achieved and no arc wobbling due to magnetic blowing occurs. Other functions and operational effects are the same as in the first embodiment.

-Third Example-
FIG. 7 shows a plasma MIG welding apparatus according to the third embodiment. The plasma torch is a plasma MIG welding torch having the same structure as that of the first embodiment, and the insert tip 1 has the same configuration as that of the first embodiment shown in FIG. In this embodiment, as shown in FIG. 7, a plasma power source for passing a plasma arc current between the electrodes 2 a and 2 b and the base material 16, contrary to the case of the first embodiment, the electrode side is positive and the base material side is negative. 17 and 18 are provided. Further, an MIG welding power source (constant voltage welding power source) 22 is provided between the wire 15 and the base material 16 to flow a welding current positive on the wire side and negative on the base material side. The shielding gas is Ar or Ar + CO ₂ or CO ₂ or Ar + H ₂ . This plasma MIG welding apparatus has the characteristics of high efficiency and deep penetration that are the characteristics of MIG, and is capable of welding without sputtering. Furthermore, welding is possible in an Ar atmosphere, and the generation of oxides in the weld metal is extremely small, making it suitable for high weight and high tension materials. In addition, it is possible to prevent a welding failure at the start portion in aluminum welding or repair a welding failure. Other functions and operational effects are the same as in the first embodiment.

-Fourth embodiment-
FIG. 8 shows a plasma wire cladding apparatus according to the fourth embodiment. The plasma torch is a plasma wire build-up torch having the same structure as that of the first embodiment, and the insert tip 1 has the same configuration as that of the first embodiment shown in FIG. In this embodiment, as shown in FIG. 8, between the electrodes 2a and 2b and the base material 16, plasma power sources 17 and 18 for passing a plasma arc current that is negative on the electrode side and positive on the base material side, the wire 15, and each electrode 2a , 2b are provided with hot wire power supplies 21a, 21b for flowing a positive current on the wire side and a negative current on the electrode side. Although the wire 15 is heated by the Joule heat of the current from the hot wire power supplies 21a and 21b, since the wire current does not flow through the base material 16, the amount of the base material 16 to be melted is small and low dilution overlay welding can be performed. . Since the wire 15 is fed perpendicularly to the base material 16, the build-up amount is stabilized without directivity even in the build-up welding while oscillating. Further, overlay welding on a vertical surface or an inclined surface is also possible. High welding using a thick wire can be performed with a stable build-up amount. Since the hot wire current flows from the electrodes 2a and 2b through the nozzles 4a and 4b and flows into the wire 15, the hot wire current is symmetrical with respect to the torch axis and is magnetically balanced in the same way as the plasma current. Stable build-up welding without magnetic blowing phenomenon can be achieved. Other functions and operational effects are the same as in the first embodiment.

-Fifth embodiment-
FIG. 9 shows a plasma powder cladding apparatus according to the fifth embodiment. The plasma torch is a plasma powder build-up torch equipped with a powder guide 6 instead of a wire guide. Other structures are the same as those of the first embodiment, and the insert tip 1 has the same configuration as that of the first embodiment shown in FIG. A powder feeder 25 feeds the powder in the powder tank 24 to the powder guide 6 at a constant speed. The plasma power sources 17 and 18 cause a plasma arc current to flow between the electrodes 2a and 2b and the base material 16 with a negative electrode side and a positive base material side. Since the powder flow is fed vertically to the base material, the yield of the powder is better than the conventional example in which the powder is fed from the side to the plasma arc, and the powder is less likely to adhere to the nozzle. Since the powder passage in the torch can be made thick and straight, it is possible to use cutting powder with poor feedability. Since symmetric plasma arcs join and collide with each other directly above the base material 16, the downward plasma flow to the base material 16 becomes weak, so that low-dilution powder overlaying is possible. Other functions and operational effects are the same as in the first embodiment.

-Sixth Example-
FIG. 10 shows a plasma keyhole welding apparatus according to the sixth embodiment. The plasma torch is a plasma keyhole welding torch equipped with a keyhole gas guide 6 instead of a wire guide. Other structures are the same as those of the first embodiment, and the insert tip 1 has the same configuration as that of the first embodiment shown in FIG. As in the case of the first embodiment, the plasma power sources 17 and 18 cause a plasma arc current to flow between the electrodes 2a and 2b and the base material 16 with a negative electrode side and a positive base material side. The keyhole gas is Ar or He or Ar + H ₂ or Ar + O ₂ or Ar + He. By injecting a small-diameter high-speed gas flow for the keyhole by the keyhole gas guide 6, it is possible to perform keyhole welding of a thick plate or low heat input deep penetration welding. Since the keyhole gas is a different route from the pilot gas (plasma gas) passing through the electrodes 2a and 2b, the electrode is not oxidized and consumed, so that an oxidizing gas can be used as the keyhole gas. Further, since the gas injection hole for the keyhole can be made small regardless of the magnitude of the plasma current, the keyhole hole can be made small and thick plate welding can be performed. Other functions and operational effects are the same as in the first embodiment.

-Seventh Example-
FIG. 11 shows a plasma cutting apparatus according to the seventh embodiment. The plasma torch is a plasma cutting torch equipped with a cutting gas guide 6 instead of the wire guide. Other structures are the same as those of the first embodiment, and the insert tip 1 has the same configuration as that of the first embodiment shown in FIG. As in the case of the first embodiment, the plasma power sources 17 and 18 cause a plasma arc current to flow between the electrodes 2a and 2b and the base material 16 with a negative electrode side and a positive base material side. The cutting gas is Ar or O ₂ or N ₂ or Ar + H ₂ . A narrow cut can be made by injecting a cutting small-diameter high-speed gas flow with the cutting gas guide 6. If the electrodes 2a and 2b are tungsten electrodes, powerful plasma cutting using O ₂ as a cutting gas can be performed without using an expensive hafnium electrode. Other functions and operational effects are the same as in the first embodiment.

1: Insert tip 1a, 1b: Electrode arrangement space 1d: Expansion port 2 (2a, 2b): Electrode 2a: First electrode 2b: Second electrode 3: Centering stone 4 (4a, 4b): Nozzle 5: Center hole 6 : Guide 7: Insert cap 8: Shield cap 9: Insulating base 9w: Cooling water passage 9p: Pilot gas passage 9s: Shield gas passage 10 (10a, 10b): Electrode fixing screw 11: First electrode base 12: Second electrode base 13: Guide 14: Insulation body 15: Wire 16: Base material 17, 18: Power source 19: Plasma 20: Pool Ma: Induced magnetic flux Mb of the first arc Mb: Induced magnetic flux Mc of the second arc Mc: Synthetic magnetic flux 21, 21a, 21b : Hot wire power supply 22: MIG welding power supply 24: Powder tank 25: Powder feeder 26: Keyhole gas 27: Cutting gas 30: Outer case

Claims (13)

A central hole is through hole, said central hole parallel to or more electrodes arranged space distributed plasma gas at equal angular pitch on a circumference Ru is supplied around the central axis of the central bore with a certain inclination angle And a plurality of nozzles communicating with each electrode arrangement space and distributed at equiangular pitches on a circumference centered on the central axis ,
Each nozzle of the plurality of nozzles receives each plasma arc current flowing through the plurality of nozzles between the electrode inserted into the electrode arrangement space and the material to be processed with respect to the central axis of the central hole. An insert tip that is inclined at an angle that merges before and after the tip surface of the tip facing the workpiece . The insert tip further includes a conical expansion port that opens to a front end surface that is continuous with the central port and faces the workpiece, and has a larger diameter than the central port, and the nozzle extends from the front surface. The insert tip according to claim 1, which is also open to the enlarged opening inside.   The insert tip according to claim 1, a wire guide for guiding a wire to the central hole of the insert tip, a plurality of electrodes having tip portions inserted into respective electrode arrangement spaces of the insert tip, and the insert tip A plasma torch comprising: a cooling water channel for cooling the gas; and a pilot gas channel for supplying pilot gas to each electrode arrangement space.   A plasma welding apparatus comprising: the plasma torch according to claim 3; and a power source for passing a plasma arc current that is negative on the electrode side and positive on the workpiece side between the plurality of electrodes and the workpiece.   Furthermore, the hot-wire-type plasma welding apparatus of Claim 4 provided with the hot wire power supply which sends a positive electric current between the said wire and a workpiece material negatively on the wire side and a workpiece target side.   The plasma torch according to claim 3, a power source for passing a plasma arc current that is positive on the electrode side and negative on the workpiece side between the plurality of electrodes and the workpiece material, and between the wire and the workpiece material A plasma MIG welding apparatus comprising a MIG welding power source for passing a positive current on the wire side and a negative current on the workpiece side.   Between the plasma torch according to claim 3, between the plurality of electrodes and the workpiece, a power source for passing a plasma arc current that is negative on the electrode side and positive on the workpiece side, and between the wire and each electrode, A plasma wire build-up device comprising a hot wire power source for flowing a positive current on the wire side and a negative current on the electrode side.   The insert tip according to claim 1, a powder guide for guiding powder to the central hole of the insert tip, a plurality of electrodes having tip portions inserted into each electrode arrangement space of the insert tip, A plasma powder build-up torch comprising a cooling water channel for cooling an insert tip and a pilot gas channel for supplying pilot gas to each electrode arrangement space.   9. A plasma powder build-up torch according to claim 8, a power source for passing a plasma arc current that is negative on the electrode side and positive on the workpiece side, between the plurality of electrodes and the workpiece material; And a means for feeding the body.   The insert tip according to claim 1, a gas guide that guides a keyhole gas to the central hole of the insert tip, a plurality of electrodes having tip portions inserted into the electrode arrangement spaces of the insert tip, A plasma keyhole welding torch comprising: a cooling water channel for cooling an insert tip; and a pilot gas channel for supplying pilot gas to each electrode arrangement space.   A plasma keyhole welding apparatus comprising: the plasma keyhole welding torch according to claim 10; and a power source for passing a plasma arc current that is negative on the electrode side and positive on the workpiece side between the plurality of electrodes and the workpiece. .   The insert tip according to claim 1, a gas guide for guiding a cutting gas to the central hole of the insert tip, a plurality of electrodes having tip portions inserted into respective electrode arrangement spaces of the insert tip, and the insert A plasma cutting torch comprising: a cooling water channel for cooling a chip; and a pilot gas channel for supplying pilot gas to each electrode arrangement space.   13. A plasma cutting device comprising: the plasma cutting torch according to claim 12; and a power source for passing a plasma arc current that is negative on the electrode side and positive on the workpiece side between the plurality of electrodes and the workpiece.

Images