JP2012130965A - Insert chip and plasma torch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insert chip having high cooling capacity, which can perform welding free from high temperature cracks and undercuts at higher speed with a stable arc, and a plasma torch using the same.SOLUTION: The insert chip includes: two electrode arrangement spaces; two nozzles communicating with each electrode arrangement space, respectively; and a V-type cooling water passage present at a plane crossing a plane where the two nozzles are distributed at the intermediate point of the two nozzles, and at which cooling water turns. The plasma torch includes two electrodes in which the respective tip parts are inserted into each electrode arrangement space thereof.

Description

  The present invention relates to a plasma torch insert tip and a plasma torch using the insert tip.

  Patent Document 1 describes a nozzle shape that improves the cross-sectional shape of a keyhole by plasma keyhole welding. Patent Document 2 describes simultaneous tanning welding by each torch in which two arc welding torches are arranged so that the arrangement of electrode tips is orthogonal to the welding line direction so as to form one molten pool. Has been. Patent Document 3 describes a composite welding method in which keyhole welding is performed by irradiating a molten pool of 0 to 2 mm ahead of the arc welding target position with laser (FIGS. 4, 0024, 0025). Patent Document 4 describes a laser welding method in which non-penetrating welding is performed with a preceding first laser beam, and through-hole (keyhole) welding is performed with a second laser beam while focusing on a hole opening formed thereby.

JP-A-8-10957 JP-A-6-155018 JP 2004-298896 A JP 2008-126315 A Japanese Patent Application No. 2009-201304

The cross section of the plasma arc of the conventional plasma arc welding by 1 torch is substantially circular as shown to Fig.8 (a). Since keyhole welding by plasma arc is impossible if the plate thickness is less than 3 mm, tanning welding (heat conduction type welding) is adopted.
B) Undercut occurs,
B) Hot cracking due to wide beads is likely to occur. In high-speed welding, the current is a high current and a wide arc, so a wide, shallow bead shape is formed, and high temperature cracking is likely to occur during solidification.

  In conventional plasma arc welding with one torch, if the speed of keyhole welding is increased at a plate thickness of 3 to 10 mm, the bead shape can be raised with a convex shape with a raised central part and an undercut with a lowered edge, which increases the speed. Is difficult. Although there is a one-pool speedup with two torches, torches must be tilted greatly to make a one-pool, and the arc is easily disturbed and unstable due to the attracting arc force and magnetic blown by tilting.

  Therefore, the present invention and the like provided an insert tip capable of realizing high-speed welding without a hot crack and undercut with a stable arc, and a plasma torch using the insert tip (Patent Document 5).

  These are insert tips each including two electrode arrangement spaces and two nozzles that are distributed on the same diameter line and communicate with each electrode arrangement space and face each other in parallel with the welding line. And a plasma torch equipped with the chip and having each electrode inserted into each electrode arrangement space.

  According to the plasma torch equipped with this insert tip, one pool two arc welding can be performed in which one arc is formed by two arcs. Since the cross section of the plasma arc is a heat source that is long and thin in the welding progress direction (y), the bead width (x direction) with respect to the amount of heat is kept narrow, and hot cracking does not occur even if the speed is increased. Moreover, a front bead can be made flat by setting it as one pool 2 arc. Although a somewhat similar effect can be obtained by parallel welding using two plasma torches separated by a certain distance, the arc distance in the welding direction is widened, so a workpiece with a short welding length (base material: material to be welded) ) Cannot be welded in the same pass, requires two-pass welding, and high speed is difficult. Further, since the arc interval is wide, the succeeding arc must remelt the bead once solidified, and high heat input is required for the subsequent welding. According to the one-pool two-arc welding using the insert tip provided with two nozzles per tip presented in Patent Document 5, the nozzle interval is short, so these problems are solved.

  By the way, in two arc plasma welding with one insert tip, the heat load applied to the insert tip becomes large. In order to increase the speed, it is necessary to improve the cooling capacity of the insert tip.

  An object of the present invention is to provide an insert tip having a high cooling capability and a plasma torch using the same, which can perform welding without hot cracking and undercut at a high speed with a stable arc.

  (1) Two electrode arrangement spaces (2a, 2b), two nozzles (3a, 3b) respectively communicating with each electrode arrangement space (2a, 2b), and an intermediate point between the two nozzles A V-shaped cooling water flow path in which the cooling water folds in a plane (III-III cutting plane: FIG. 3 paper plane) intersecting the plane (II-II cutting plane: FIG. 2 paper plane) where the two nozzles are distributed. (4a, 4b) and an insert tip (1).

  In addition, in order to facilitate understanding, in parentheses, the correspondence of the examples shown in the drawings and described later, or the symbols or corresponding matters of corresponding elements are added for reference. The same applies to the following.

  According to the plasma torch equipped with the insert tip (1), one pool two arc welding can be performed in which one melting pool is formed by two arcs. In this case, since the cross section of the plasma arc becomes a heat source that is long and thin in the welding progress direction (y), the bead width (x direction) with respect to the amount of heat is kept narrow, and hot cracking does not occur even if the speed is increased. Moreover, by setting it as one pool 2 arc, in plate | board thickness 3-10mm, a keyhole welding can be carried out by a preceding arc, and a wide tanning welding can be carried out by a subsequent arc, and a surface bead can be made flat. If the plate thickness is less than 3 mm, it is possible to carry out digging welding with a leading arc and flatten the front bead with a trailing arc.

  Although a somewhat similar effect can be obtained by parallel welding using two plasma torches separated by a certain distance, the arc interval in the welding progress direction becomes wide, so with a work with a short weld length (material to be welded) Welding in the same pass is impossible, and two-pass welding is required, and it is difficult to increase the speed. Further, since the arc interval is wide, the succeeding arc must remelt the bead once solidified, and high heat input is required for the subsequent welding. According to the one-pool two-arc welding using the insert tip of the present invention having two nozzles in one tip, these problems are solved because the nozzle interval is short.

  In addition, the insert tip (1) has a plane (Fig. 3 paper surface) that intersects the plane (Fig. 2 paper surface) where the two nozzles are distributed at the midpoint of the two nozzles (3a, 3b). Since it has a V-shaped cooling water flow path (4a, 4b), the cooling water smoothly turns back near the tip surface (base material facing surface) of the chip (1), and water or bubbles do not stay locally. Chip cooling capacity is high. V-shaped cooling water flow paths (4a, 4b) can be formed at low cost by making holes so as to be oblique to the end face of the chip and intersect at the tip. Therefore, welding can be performed at higher speed by increasing the welding power.

It is the top view which looked down at the inside of the outer cylinder of the plasma torch of the 1st example of the present invention. It is the II-II sectional view taken on the line of the plasma torch shown in FIG. It is the III-III sectional view taken on the line of the plasma torch shown in FIG. (A) is an enlarged sectional view of the insert tip of the second embodiment, (b) is an enlarged sectional view showing only the base 1a of the insert tip shown in (a), (c) is a nozzle member 20a to be mounted on the base, It is an expanded sectional view of 20b. (A) is an enlarged sectional view of the insert tip of the third embodiment, (b) is an enlarged sectional view showing only the base body 1b of the insert tip shown in (a), (c) is a nozzle member 20c attached to the base body, It is an expanded sectional view of 20d.

  (2) The insert tip has one electrode arrangement space (2a / 2b) and a pair of nozzle members (20a, 20b / 20c, 20d) in which one nozzle (3a / 3b) communicating with the electrode arrangement space is opened. ) And a chip base (1a / 1b) in which these nozzle members are coupled, and each nozzle member is detachable from the chip base (1a) (1), the insert tip (see FIG. 4). / Figure 5).

  According to this, when the nozzle part at the lower end of the nozzle member is deformed or damaged by high heat, the nozzle member can be replaced with a new one, and the chip base can be used as it is, so that the maintenance cost can be reduced.

  (3) The chip base (1a / 1b) has a female screw hole (19a, 19b) on the bottom end surface side of the base of the hole (18a, 18b / 18c, 18d) into which the nozzle member is inserted. The insert tip according to (2) above (FIG. 4 / FIG. 5), wherein a lower portion has a male screw that is screwed into the female screw hole.

  According to this, the nozzle member can be easily attached and detached without giving deformation to the chip base by screwing.

  (4) The tip base (1b) has a tapered inner peripheral surface (18c, 18d) of a lower diaphragm between the female screw hole (19a, 19b) and the upper end surface of the base, and the male screw of the nozzle member The insert tip according to (3), wherein there is a tapered outer peripheral surface (23a, 23b) of the lower diaphragm that contacts the tapered inner peripheral surface between the upper portion and the upper portion.

  According to this, the taper outer peripheral surface (23a, 23b) of the nozzle member is screwed into the taper inner peripheral surface (18c, 18d) of the chip base (1b) by screwing the nozzle member (20c, 20d) into the chip base (1b). The pressure contact is made by surface contact, the heat transfer resistance from the nozzle member (20c, 20d) to the chip base (1b) is low, and the cooling capacity of the nozzle member (20c, 20d) is high.

  (5) The insert tip according to any one of (1) to (4) above, and two electrodes (12a, 12b) each having a tip inserted into each electrode arrangement space (2a, 2b) of the insert tip And a plasma torch (FIG. 2).

  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 the inside of the outer cylinder 14 of the plasma torch according to the first embodiment, that is, the plasma arc torch of the first embodiment as viewed from above, and FIG. 2 shows a longitudinal section in the direction of II-II line in FIG. Show the surface. The plasma arc torch of the first embodiment is of a form that performs plasma welding. Referring to FIG. 2, the insert chip 1 is fixed to the chip base 5 by screwing the insert cap 6 to the chip base 5. The chip base 5 is fixed to the insulating body 7, and the electrode bases 10 a and 10 b and the insulating spacer 11 are fixed to the insulating body 7.

  The shield cap 8 is fixed to the insulating body 7. The first electrode base 10a and the second electrode base 10b separated in the diameter direction of the outer cylinder 14 by two are separated by an insulating spacer 11.

  In the insert chip 1 of this embodiment, two electrodes are distributed on the same diameter line orthogonal to the central axis (z) of the chip 1 and are equidistant from the central axis and extend parallel to the central axis (z). Arrangement spaces 2a and 2b, and two nozzles 3a and 3b that communicate with each of the spaces 2a and 2b and open at the front end surface (lower end surface) facing the base material (not shown) are provided. In the present embodiment, these nozzles 3a and 3b are also distributed on the same diameter line perpendicular to the central axis (z) of the tip (outer cylinder 14), and are parallel to and equidistant from the central axis.

  The tip portions of the first electrode 12a and the second electrode 12b that pass through the insulating body 7 and are fixed to the electrode bases 10a and 10b with screws 13a and 13b are inserted into the electrode arrangement spaces 2a and 2b, respectively. Centering stones 9a and 9b are positioned at the axial center positions of the spaces 2a and 2b. Nozzles 3a and 3b connected to the respective electrode arrangement spaces 2a and 2b are opened at the front end surface (lower end surface) of the insert tip 1 facing the base material (not shown). The direction in which the straight line connecting the nozzles 3a and 3b extends is the welding direction. The chip 1 is wide in the welding direction because the two electrode arrangement spaces 2a and 2b are arranged in the welding direction.

  FIG. 3 shows a longitudinal section in the direction of line III-III in FIG. The tip 1 has a narrow width in a direction crossing the welding direction, and V-shaped cooling water flow paths 4a and 4b are formed in the narrow width direction. The cooling water flow paths 4a and 4b are planes (III-III) intersecting with a plane (II-II cut surface: paper surface of FIG. 2) where the two nozzles are distributed at an intermediate point between the two nozzles 3a and 3b. (Cut surface: paper surface of FIG. 3). As shown in FIG. 3, the water flow paths 4a and 4b are made to flow by making two holes 4a and 4b obliquely from the upper end toward the same point on the lower end side and intersecting at the bottom of the hole.

  The cooling water injected into the water flow pipe 16a passes through the water flow paths of the electrode base 10a, the insulating body 7 and the chip base 5 and enters one flow path 4a of the V-shaped water flow path of the chip 1 to reach the hole bottom. Enters the other flow path 4b, flows through the water flow paths of the chip base 5, the insulating body 7 and the electrode base 10b to the water flow pipe 16b and flows out of the torch. While the cooling water flows through the V-shaped water flow paths 4 a and 4 b of the chip 1, heat is extracted from the chip 1. That is, the chip 1 is cooled. Since the cooling water hits the slope of the flow path 4a when entering one flow path 4a, there is no turbulence (vortex or the like) of the water flow. Similarly, the cooling water flowing from one flow path 4a to the other flow path 4b is flow path 4b. The water flow is not disturbed and is smooth and does not cause stagnation of cooling water or bubbles, so that the cooling capacity of the chip is high.

  Referring again to FIGS. 1 and 2, the pilot gas enters the electrode arrangement spaces 2a and 2b through the pilot gas pipes 15a and 15b and the electrode insertion space, becomes plasma at the electrode tip, and passes through the nozzles 3a and 3b. Erupt from the tip of the torch. The shield gas passes through the shield gas pipe 17 and enters the cylindrical space between the inner cap 7 and the shield cap 8 and is ejected from the tip of the torch toward a base material (not shown).

  A pilot arc is generated between each electrode 12a, 12b and the tip 1 by each pilot power source, and a plasma arc current is passed between the electrodes 12a, 12b and the base material so that the electrode side is negative and the base material side is positive. A welding arc (plasma arc) is generated by a plasma power source (for welding or preheating) that feeds the preceding electrode 12a in the direction and a plasma power source (for tanning welding or main welding) that feeds the subsequent electrode 12b in the welding direction Then, a plasma arc current flows between each electrode 12a, 12b and the base material, and 1 pool 2 arc welding is realized. In this welding mode, welding or preheating by the plasma arc of the electrode 12a and tanning welding or main welding by the electrode 12b are performed. That is, a plasma pool of tanning welding or main welding hits the molten pool generated by welding or preheating with the preceding electrode 12a and the subsequent electrode 12b, and sends the molten pool formed by, for example, keyhole welding backward, Subsequent tanning welding levels the molten bead formed by keyhole welding. Thereby, it becomes a tanning weld bead smoothly connected to the base material surface. In the case of a thin plate of less than 3 mm, since keyhole welding is impossible, a bead is formed by preceding welding or preheating, and this is changed to a smooth bead by subsequent tanning welding. Unlike conventional high-current one-pool wide welding, high-speed welding with a narrow bead width can be performed with the lowest necessary minimum current by dividing the functions into the preceding and following functions. The speed can also be increased by using the leading arc as preheating and performing the main welding with the trailing arc. In any case, by using the tip 1 in which the V-shaped cooling water channels 4a and 4b having a high cooling capacity are used, welding power can be increased and welding can be performed at a higher speed.

-Second Example-
FIG. 4A shows a second embodiment of the insert tip of the present invention. This is used in place of the insert tip 1 of the plasma torch shown in FIGS. In the insert chip of the second embodiment, a pair of nozzle members 20a and 20b made of a metal having high thermal conductivity, for example, copper or a copper alloy, is similarly used for the chip base 1a made of metal having high thermal conductivity. Inserted into the insertion holes 18a and 18b and integrated with the chip base 1a by screwing the male screws 22a and 22b at the lower ends of the nozzle members 20a and 20b into the female screw holes 19a and 19b at the lower ends of the insertion holes 18a and 18b. It is. A pair of nozzle members 20a and 20b is removed from the insert chip. FIG. 4B shows the chip base 1a, and FIG. 4C shows a pair of nozzle members 20a and 20b.

  Each nozzle member 20a, 20b is provided with electrode arrangement spaces 2a, 2b and two nozzles 3a, 3b opened at the front end surfaces (lower end surfaces) communicating with the spaces 2a, 2b. The holes 21a and 21b into which the lower ends of the centering stones 9a and 9b (FIG. 2) are inserted on the upper ends of the electrode arrangement spaces 2a and 2b are hexagonal holes into which hexagonal drivers are inserted. Male screws 22a and 22b are engraved on the outer peripheral surface of the lower end side of 2b.

  The chip base 1a to which such nozzle members 20a and 20b are mounted is distributed on the same diameter line perpendicular to the central axis (z) of the chip base 1a, and is equidistant from the central axis and has a central axis (z ) There are two nozzle member insertion holes 18a, 18b extending in parallel. Male screws 19a and 19b are engraved on the inner peripheral surface on the lower end side of the insertion holes 18a and 18b. Moreover, since the V-shaped water flow path having the same shape as the V-shaped water flow paths 4a and 4b (FIG. 3) of the insert chip 1 of the first embodiment is formed in the same position on the chip base 1a, the second The cooling ability of the insert chip of the embodiment is high.

  A pair of nozzle members 20a and 20b shown in FIG. 4C is inserted into the insertion holes 18a and 18b of the chip base 1a shown in FIG. 4B, and a hexagonal hole on the upper end side of the nozzle members 20a and 20b. The insert tip shown in FIG. 4 (a) is completed by inserting the hexagonal columnar tip of the hexagon driver into 21a and 21b and screwing it around. When the periphery of the nozzles 3a, 3b of the insert chip is deformed or melted by the plasma arc, the nozzle members 20a, 20b are removed from the chip base 1a using a hexagonal screwdriver, and a new nozzle member is mounted on the chip base 1a. Thus, the nozzle substrate 1a can be used for a long time.

-Third Example-
FIG. 5A shows a third embodiment of the insert tip of the present invention. This is also used in place of the insert tip 1 of the plasma torch shown in FIGS. As in the second embodiment, the insert tip of the third embodiment is a pair of nozzle members 20c, 20d made of a metal having a high thermal conductivity, and a chip base 1b made of a metal having a high thermal conductivity. The male screws 22a and 22b at the lower ends of the nozzle members 20c and 20d are screwed into the female screw holes 19a and 19b at the lower ends of the insertion holes 18c and 18d to be integrated with the chip base 1b. Is. A pair of nozzle members 20c and 20d is removed from the insert tip, and FIG. 5B shows a chip base 1b and FIG. 5C shows a pair of nozzle members 20c and 20d.

  The nozzle members 20c, 20d of the third embodiment are different from those of the second embodiment in that the outer peripheral surfaces between the male screws 22a, 22b and the upper portion are tapered outer peripheral surfaces 23a, 23b of the lower diaphragm. Correspondingly, in the chip base 1b of the third embodiment, the tapered inner peripheral surface 18c of the lower diaphragm aligned with the tapered outer peripheral surfaces 23a, 23b is provided between the female screw holes 19a, 19b and the upper end surface side. There is 18d. Other insert tip structures are the same as in the second embodiment.

  In the insert chip of the third embodiment, the nozzle members 20c and 20d are screwed into the chip base 1b so that the taper outer peripheral surfaces 23a and 23b of the nozzle member are in pressure contact with the taper inner peripheral surfaces 18c and 18d of the chip base 1b. The heat transfer resistance between the nozzle members 20c, 20d / chip base 1b is low, and the cooling capacity of the nozzle members 20c, 20d is further high.

  In the nozzle members of the second and third embodiments, the hexagonal holes 21a and 21b may be round holes with a groove for receiving the tip of a minus or plus driver on the tip surface of the nozzle member.

1: Insert chip 1a, 1b: Chip base 2a, 2b: Electrode arrangement space 3a, 3b: Nozzle 4a, 4b: Water flow path 5: Chip base 6: Inner cap 7: Insulation body 8: Shield cap 9a, 9b: Centering stone 10a, 10b: electrode base 11: insulating spacers 12a, 12b: electrodes 13a, 13b: cap screw 14: outer cylinder 15a, 15b: pilot gas pipe 16a, 16b: water flow pipe 17: shield gas pipe 18a, 18b: nozzle member insertion Holes 18c, 18d: Tapered inner peripheral surfaces 19a, 19b: Female screw holes 20a, 20b: Nozzle members 20c, 20d: Nozzle members 21a, 21b: Hexagonal holes 22a, 22b: Male screws 23a, 23b: Tapered outer peripheral surfaces

Claims (5)

  Two electrode arrangement spaces, two nozzles respectively communicating with each electrode arrangement space, and a plane intersecting with a plane where the two nozzles are distributed at an intermediate point between the two nozzles An insert chip comprising: a V-shaped cooling water flow path where the cooling water is turned back.   The insert chip is composed of one electrode arrangement space, a pair of nozzle members in which one nozzle communicating with the electrode arrangement space is opened, and a chip base body in which these nozzle members are coupled. The insert chip according to claim 1, wherein the insert chip is removable.   The insert according to claim 2, wherein the chip base has a female screw hole on a lower end surface side of the base of a hole into which the nozzle member is inserted, and a male screw that is screwed into the female screw hole on a lower portion of the nozzle member. Chip.   The chip base has a tapered inner peripheral surface of a lower diaphragm between the female screw hole and the upper end surface side of the base, and a lower diaphragm that abuts the tapered inner peripheral surface between the male screw and the upper portion of the nozzle member. The insert tip according to claim 3, which has a tapered outer peripheral surface.   A plasma torch comprising: the insert tip according to any one of claims 1 to 4; and two electrodes each having a tip portion inserted into each electrode arrangement space of the insert tip.

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