JPH11320103A - Torch for plasma build up welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out a smooth and sure welding by connecting a body and a nozzle part by means of a connecting pipe and by separating the nozzle part from the body so as to make a contact interference difficult between a work and the body. SOLUTION: A screw part 47a formed at a base end part of a connecting pipe 47 is screwed in a screw hole 42a formed at a tip end inside part of an inner tube part 42 of a body 40. A plasma gas connecting route 48 and two material connecting routes 49 are formed inside the connecting pipe 47. A screw part 50a formed on a base end part of a tip 50 is screwed in a screw hole 47b formed at a chip end inside of the connecting pipe 47. A plasma arc injection hole 51 and four powder jetting holes 52 are formed on the chip 50. A material route 44, the material connection routes 49 and the powder jetting holes 52 are smoothly connected by means of grooves 47c, 50b formed on a body 40 side end face of the connecting pipe 47 and on a connecting pipe 47 side end face of the chip 50. Further, it is so designed that the screw part 50a of the chip 50 can be screwed in the screw hole 42a of the body 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma welding overlay torch.

[0002]

2. Description of the Related Art In recent years, as a method of welding alloys or the like which are difficult to form into small diameter wires or the like which are difficult to process, a powder overlay welding method using these alloys or the like as powder has been widely applied. It has become. The structure of a plasma overlay welding torch used in this type of powder overlay welding method will be described with reference to FIG.

[0003] The plasma overlay welding torch T0 has a cylindrical body 10, which has an inner cylinder 12 having a plasma gas supply path 11 for supplying a plasma gas PG and an inner cylinder 12. An outer cylinder 15 is provided around the inner cylinder 12 and has a plurality of material passages 14 therein for introducing the welding powder 13 by the powder supply gas CG. A shield tube 16 is mounted outside the outer tube 15, and a gap between the outer tube 15 and the shield tube 16 is a shield gas supply path 17 for supplying a shield gas SG. .

At the lower ends of the outer cylinder 15 and the inner cylinder 12, a chip 20 is arranged. The chip 20 has a plasma arc injection hole 21 communicating with the plasma gas supply passage 11, and a chip 20 provided around the plasma arc injection hole 21. And a powder ejection hole 22 communicating with the material passage 14. Chip 20
Plays the role of a nozzle part, and the powder ejection holes 2
2 is formed toward the plasma arc injection hole 21 so that the welding powder 13 to be injected is supplied to the plasma arc P injected from the plasma arc injection hole 21.

Further, the plasma gas supply path 11 of the inner cylinder 12 is
Is provided with a rod-shaped electrode 30 for generating an arc A between itself and the tip 20. A high voltage is applied between the rod-shaped electrode 30 and the chip 20 below the inner cylinder 12 by a pilot arc power supply (not shown). Is applied. A high voltage is applied between the rod-shaped electrode 30 and the work by a transferred arc power supply (not shown).

[0006] In the case of performing the overlay welding on the periphery of a work (workpiece) using the plasma overlay welding torch T0 having the above configuration, first, the rod-shaped electrode 30 of the plasma overlay welding torch T0 is connected to the welding electrode. An arc A is generated by a pilot arc power supply between the chip 20 below the inner cylinder 12 and the plasma gas PG and the shield gas SG to the plasma gas supply path 11 and the shield gas supply path 17, respectively.

When a high voltage is applied between the rod-shaped electrode 30 and the work by the transferred arc power supply, the plasma gas PG passes through the arc A and the tip 20
Of the rod-shaped electrode 3
A plasma arc P is generated between 0 and the work. Further, the powder supply gas CG including the welding powder 13 is supplied to the material passage 14, and the welding powder 13 is ejected from the powder ejection hole 22 of the chip 20 into the plasma arc P.

The ejected welding powder 13 is melted by the plasma arc P and is overlaid on the periphery of the work.
Weld beads are formed. Then, by rotating the work, the processing of one work is completed by forming a weld bead in a closed ring over the entire periphery of the periphery of the work, and the transfer arc power supply and the pilot arc power supply are turned off and the plasma gas is turned off. PG,
The supply of the powder supply gas CG and the shield gas SG is stopped.

[0009]

However, for example, in a stepped shaft for supplying a cooling medium of an ice making machine as shown in FIG. 3, HCl is contained in the cooling medium, and wear is caused in a low-temperature environment. In order to keep the life as long as possible by holding down as much as possible, it is necessary to form the hardfacing portion 1 on the stepped portion.
In this case, depending on the dimensions of the stepped shaft for supplying the cooling medium (for example, the large-diameter portion D1 = 60 mm and the small-diameter portion D2 = 15 mm), the workpiece and the above-mentioned conventional plasma overlay welding torch interfere with each other. Therefore, there is a problem that a region where the build-up welding cannot be performed is formed at the base of the stepped portion.

This problem also occurs in the finned shaft (screw) shown in FIG. That is, in this finned shaft, it is necessary to form the hardfacing portion 3 on the entire fin 2, but there is an area where the buildup welding cannot be performed at the root of the fin 2.

The present invention has been made in view of the above circumstances, and an object of the present invention is to prevent a contact interference with a work beforehand, and to smoothly and surely build up the surface. An object of the present invention is to provide a welding torch for a plasma overlay which can be welded.

[0012]

According to a first aspect of the present invention, there is provided a material passage in which a plasma gas supply path is formed at the center, and a welding powder is introduced around the plasma gas supply path by a powder supply gas. A plasma arc injection hole provided at one end of the body and communicating with the plasma gas supply path, and a powder injection hole provided around the plasma arc injection hole and communicating with the material passage. A nozzle provided with a rod-shaped electrode disposed in a plasma gas supply path of the body for igniting an arc, wherein a plasma arc is generated by a plasma gas passing through the arc, and the welding is performed during the plasma arc. In a plasma overlay welding torch for supplying powder for welding and overlay welding on the powder for welding, the above-mentioned bob is inserted between the body and a nozzle having a smaller diameter than the body. Diameter of the connecting tube is provided from the I,
The connecting pipe is configured to allow the plasma gas supply passage and the material passage of the body to communicate with the plasma arc injection hole and the powder injection hole of the nozzle portion, respectively. According to the first aspect, the body and the nozzle portion are connected by the connecting pipe, and the nozzle portion is separated from the body, so that the body which is likely to contact and interfere with the work (workpiece) is separated from the work. Makes it difficult to cause contact interference.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, a connecting pipe is provided detachably on the body and the nozzle portion. In this claim 2,
By connecting the connecting pipe to the body and the nozzle part in a detachable manner, if the body is in a positional relationship that is unlikely to interfere with the work, the connecting pipe is removed and the body and the nozzle part are directly connected and used. .

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG. In the drawing, reference numeral T denotes a welding torch for plasma overlay, and the welding torch T for plasma overlay is used.
Has a substantially umbrella-shaped body 40 connected to the torch body TA, as shown in FIG.
An inner cylinder part 42 having a plasma gas supply path 41 for supplying a plasma gas PG therein, and a welding powder 43 introduced into the inside by a powder supply gas CG connected to a tip of the inner cylinder part 42. Material passages 44 and 12 shield gas supply passages 4 for supplying the shield gas SG.
5 is provided with an umbrella-shaped portion 46 having a substantially frustoconical shape and a tapered shape. A screw hole 42a is formed inside the distal end of the inner cylindrical portion 42 of the body 40.
A threaded portion 47a formed at the base end of the connection pipe 47 is screwed into a. Inside the connection pipe 47, a plasma gas communication passage 48 communicating with the plasma gas supply passage 41 of the body 40 and two material communication passages 49 communicating with the material passage 44 are formed.

A screw hole 47 is provided inside the distal end of the connection pipe 47.
b is formed in the screw hole 47b.
A screw portion 50a formed at the base end portion is screwed. The tip 50 has a plasma arc injection hole 51 communicating with the plasma gas communication passage 48 and a plasma arc injection hole 51 provided around the plasma arc injection hole 51 and communicating with the material communication passage 49.
The powder ejection holes 52 are formed. The tip 50 plays a role as a nozzle portion, and the powder ejection holes 52
Are formed toward the plasma arc injection holes 51 so that the welding powder 43 to be injected is supplied to the plasma arc P injected from the plasma arc injection holes 51. In addition, annular grooves 47c and 50b are respectively formed on the end face of the connection pipe 47 on the body 40 side (base end side) and the end face of the tip 50 on the connection pipe 47 side (base end side). The annular passages 47c and 50b allow the material passage 44, the material communication passage 49, and the powder ejection hole 52 to smoothly communicate with each other. further,
The screw hole 42a of the body 40 and the screw portion 4 of the connection pipe 47
7a, screw hole 47b and screw portion 50a of chip 50
Are formed in the same shape, so that the screw portion 50a of the chip 50 can be screwed into the screw hole 42a of the body 40.

A funnel-shaped shield cylinder 53 is mounted on the torch main body TA. A gap between the shield cylinder 53 and the body 40, the connection pipe 47 and the chip 50 is connected to the shield gas supply passage 45. The shield gas communication passage 54 communicates therewith. Further, the arc A is provided between the plasma gas supply passage 41 of the inner cylinder portion 42 and the tip 50.
A rod-shaped electrode 55 made of, for example, tungsten (tungsten containing lanthanum) is disposed via a tubular member 56, and a pilot arc power supply (not shown) is provided between the rod-shaped electrode 55 and the chip 50. A high voltage is applied. A high voltage is applied between the rod-shaped electrode 55 and the work by a transferred arc power supply (not shown).

The tubular member 56 is formed of an electrically insulating material having heat resistance such as BN (boron nitride), for example. A plurality of grooves 56a corresponding to the gas supply path 41 and the plasma gas communication path 48 are formed,
The plasma gas supply path 41 and the plasma gas communication path 48 are configured to be separated from the rod-shaped electrode 55. The cylindrical member 56 has a plurality of plasma gas introduction holes 5 for ejecting the plasma gas PG inward and toward the tip near the tapered tip of the rod-shaped electrode 55.
6b is formed so as to be continuous with the groove 56a.

The overlay welding by the plasma overlay welding torch T configured as described above is performed as follows. First, the rod-shaped electrode 55 of the welding torch T for plasma overlaying.
An arc A is generated by a pilot arc power supply between the semiconductor chip and the chip 50, and a plasma gas PG and a shield gas SG made of, for example, argon gas are supplied to the plasma gas supply path 41 and the shield gas supply path 45, respectively. Thus, the plasma gas PG is transferred to the plasma gas introduction hole 56b of the tubular member 56 connected to the plasma gas supply path 41, and is ejected from the opening toward the inside and the tip of the tubular member 56. You. Also,
The shielding gas SG is injected from the shielding gas communication passage 54 and shields the plasma arc P so as not to get caught in an external airflow.

When a high voltage is applied between the rod-shaped electrode 55 and the work (workpiece) by the transferred arc power supply, the plasma gas PG passes through the arc A and is ejected from the plasma arc injection hole 51 of the tip 50. Then, a plasma arc P is generated between the rod-shaped electrode 55 and the work. Further, the powder supply gas CG including the welding powder 43 is supplied to the material passage 44, and the powder is supplied from the powder ejection hole 52 of the chip 50 into the plasma arc P via the material communication passage 49 of the connection pipe 47. And the welding powder 43 is ejected. In this case, since the connecting pipe 47 and the tip 50 have grooves 47c and 50b respectively formed at the base end surfaces thereof, the welding powder between the material passage 44, the material communication passage 49 and the powder ejection hole 52 is formed. The powder supply gas CG including the powder 43 is smoothly transferred, and the powder supply gas CG including the uniform and equal amount of the welding powder 43 is ejected from the four powder ejection holes 52. Then, the ejected welding powder 43 is melted by the plasma arc P and is overlay-welded to the work to form a weld bead.

At this time, the welding torch T for plasma overlay is used.
Since the connecting pipe 47 having a smaller diameter than the body 40 and substantially the same diameter as the tip 50 is interposed between the body 40 and the tip 50, the body 40 having a larger diameter than the tip 50 or the connecting pipe 47. Without approaching and interfering with the work,
The body 40 does not hinder the welding process. Also,
If there is no possibility that the body 40 will interfere with the workpiece, the tip 50 may be screwed directly into the tip of the body 40. In this case, the shield cylinder 53, the rod-shaped electrode 55, and the cylindrical member 56 are replaced with shorter ones.

[0021]

According to the first aspect of the present invention, the body and the nozzle portion are connected to each other by the connecting pipe, and the nozzle portion is separated from the body. By separating from the work, the two hardly interfere with contact. Therefore, the body can be smoothly and reliably welded without hindering the welding process.

According to the second aspect of the present invention, the connection pipe is detachably connected to the body and the nozzle portion,
When the body is in a positional relationship that does not easily cause contact interference with the work, the connection pipe can be removed and the body and the nozzle portion can be directly connected and used. Therefore, the connection pipe can be appropriately used as an adapter according to the welding situation.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a welding torch for a plasma overlay according to the present invention.

FIG. 2 is a longitudinal sectional view showing a conventional example.

FIG. 3 is a perspective view showing an example of a workpiece (workpiece) to be welded by overlay welding.

FIG. 4 is a perspective view showing another example of the work to be welded by overlay welding.

[Explanation of symbols]

 T Welding torch for plasma overlay PG Plasma gas CG Powder supply gas SG Shielding gas P Plasma arc A Arc 40 Body 41 Plasma gas supply path 43 Welding powder 44 Material passage 47 Connection pipe 50 Tip (nozzle part) 51 Plasma Arc injection hole 52 Powder injection hole 55 Rod electrode

Claims (2)

[Claims] 1. A plasma gas supply path is formed in the center,
A body in which a material passage for introducing the welding powder by the powder supply gas is formed around the plasma gas supply path,
A nozzle portion provided at one end of the body and having a plasma arc injection hole communicating with the plasma gas supply path, and a powder injection hole provided around the plasma arc injection hole and communicating with the material passage; A rod-shaped electrode provided in the plasma gas supply path for igniting an arc, generating a plasma arc by a plasma gas passing through the arc, and supplying the welding powder into the plasma arc. In the plasma cladding welding torch for overlay-welding the powder for welding, between the body and a nozzle having a smaller diameter than the body,
A connection pipe smaller in diameter than the body is provided, and the connection pipe is configured to communicate the plasma gas supply passage and the material passage of the body with the plasma arc injection holes and the powder injection holes of the nozzle portion, respectively. A welding torch for plasma cladding characterized by the above. 2. The welding torch for plasma cladding according to claim 1, wherein the connecting pipe is detachably provided on the body and the nozzle part.