JP5647884B2 - Plasma torch electrode and plasma torch - Google Patents

Description

  The present invention relates to an electrode for a plasma torch that converts a working gas into plasma and cuts a workpiece, and a plasma torch using the electrode.

  As is well known, in plasma cutting, an arc is generated between a plasma torch electrode provided in a nozzle to which oxygen gas is supplied and a workpiece, and oxygen gas injected from the nozzle is converted into plasma. The workpiece is cut by the plasma arc generated thereby.

The electrode for the plasma torch is formed of an electrode base disposed in the nozzle and an refractory material such as hafnium that is disposed substantially at the center of the tip of the electrode base and coaxial with the oxygen gas ejection hole of the nozzle. Material.
For such plasma cutting, for example, techniques as disclosed in Patent Documents 1 and 2 are disclosed.

  For example, in Patent Document 1, the pressure of oxygen gas supplied from a torch main body when processing a workpiece with plasma is detected, and the pressure of the oxygen gas is compared with a threshold value, and the plasma torch electrode is consumed. , And the lifespan is detected.

  Further, Patent Document 2 discloses a technique for extending the electrode life by finding that the cross-sectional area of the electrode material arranged at the center of the tip surface of the electrode affects the applied current value and obtaining the optimum equation thereof. ing.

JP-A-6-23556 Japanese Patent No. 4368606

By the way, as a result of the inventor of the present invention diligently studying the life of the electrode for the plasma torch, the high melting point material constituting the electrode material diffuses radially (in the radial direction) to the electrode substrate side during plasma cutting, and the electrode material It was found that this was due to wear (mass loss).
The mechanism by which the electrode material diffuses and moves to the electrode substrate side is under intensive research, but the electrode material that has become molten when the plasma arc is generated moves to the electrode substrate side along the tip surface of the plasma torch electrode. It is presumed to be due to spillage or scattering.

  On the other hand, it has been found that when the diffusion and movement of the electrode material toward the electrode substrate side is reduced, the melting of the electrode substrate is suppressed, and the plasma torch electrode as the cathode in the middle stage of the plasma torch electrode consumption is stabilized.

  From the above, by extending the time that the molten electrode material stays at the original position of the electrode material, and suppressing the diffusion and movement of the electrode material to the electrode base side on the electrode tip surface of the plasma torch Further, it is considered that the life of the electrode for the plasma torch is extended by suppressing the melting of the electrode substrate.

  The present invention has been made in view of such circumstances, and a high melting point material (for example, hafnium) constituting the electrode material diffuses along the tip surface of the electrode substrate on the tip surface of the plasma torch electrode. It is an object of the present invention to provide a plasma torch electrode and a plasma torch that can suppress the above-described phenomenon and thereby extend the life of the plasma torch electrode.

In order to solve the above problems, the present invention proposes the following means.
The invention according to claim 1 is a plasma having an electrode base and an electrode material disposed on a tip surface of the electrode base, and applying a current between the electrode material and a workpiece to generate a plasma arc. It is an electrode for a torch, and a groove surrounding the electrode material is formed on the distal end surface of the electrode base body without opening a flow path from the outside , and is opened only at the distal end side so as to be spaced from the electrode material. It is characterized by.

According to a third aspect of the present invention, a plasma torch electrode is held coaxially with the nozzle in a torch body in which a nozzle for ejecting a working gas is formed at the tip, and the torch body and the plasma torch electrode A plasma torch in which a working gas passage through which a working gas supplied to the nozzle circulates is formed, and the plasma torch electrode according to claim 1 or 2 is provided.

According to the plasma torch electrode and the plasma torch according to the present invention, the electrode material is suppressed from moving and diffusing to the electrode base body along the tip surface of the plasma torch electrode.
Further, since the groove is formed in a V-groove shape and the radial interval can be set larger than the depth direction, the diffusion of the high melting point material constituting the electrode material can be efficiently suppressed. it can.
As a result, the decrease in the high melting point material constituting the electrode material is suppressed, and as a result, the life of the plasma torch electrode can be extended.

Invention of Claim 2 is the electrode for plasma torches of Claim 1 , Comprising: The said electrode material is arrange | positioned in the hole located in the center of the front end surface of the said electrode base | substrate, The said groove | channel is the said groove | channel. It is arranged coaxially with the electrode material .

According to the electrode for the plasma torch, the electrode material is disposed in the hole located in the center of the tip surface of the electrode base, and the groove is disposed coaxially with the electrode material. This can extend the life of the electrode for the plasma torch .

  According to the plasma torch electrode and the plasma torch according to the present invention, it is possible to suppress the diffusion of the electrode material to the electrode substrate on the tip surface of the plasma torch electrode.

It is a front sectional view showing an electrode for a plasma torch. It is the fragmentary sectional view which expanded the front-end | tip part of FIG. It is a front sectional view of a plasma torch to which a plasma torch electrode is applied. It is a figure which shows the use condition of FIG.

An embodiment of the present invention will be described with reference to FIGS.
FIG. 3 is a front sectional view of a plasma torch 1 to which an electrode for a plasma torch is applied. In this figure, reference numeral 1 denotes a plasma torch, reference numeral 1A denotes a torch main body formed hollow, and the inside of the torch main body 1A A nozzle 2 is formed at the tip of the nozzle.
A plasma torch 1 according to an embodiment includes a torch body 1A and a plasma torch electrode 10.
The torch body 1A has a hollow portion and a cooling water channel 1B formed therein, and a plasma torch electrode 10 is disposed in the hollow portion.
A working gas passage 3 through which a working gas (for example, oxygen gas) flows is formed between the plasma torch electrode 10 and the inner peripheral surface of the torch main body 1A, and is supplied via the working gas passage 3. A working gas is injected from the nozzle 2.

  Further, a head cap 4 that defines a cooling water channel 1B is attached to a position outside the working gas ejection hole 2A of the nozzle 2 in the main body 1A.

  As shown in FIGS. 1 and 2, the plasma torch electrode 10 includes an electrode base 11 and an electrode material 12 disposed in a hole 11B at the center of the tip surface 11A of the electrode base 11. 12 is made of hafnium, for example, and the electrode base 11 is made of copper.

Further, the plasma torch electrode 10 is used as a cathode, and the workpiece W is used as an anode, and is connected to a power source (not shown).
Then, as shown in FIG. 4, the plasma torch electrode 10 generates an arc between the workpiece W positioned below and the working gas injected from the nozzle 2 through the working gas passage 3. The workpiece W is cut by the plasma arc P generated thereby.

  As shown in FIGS. 1 and 2, a ring-shaped groove 20 is formed on the distal end surface 11 </ b> A of the electrode base 11 located around the electrode material 12. The groove 20 has a V-shaped cross section that is perpendicular to the direction in which the groove 20 extends, and the axis O of the electrode member 12 that is formed in a substantially cylindrical shape on the tip surface 11A of the electrode substrate 11 It is arranged coaxially with the electrode material 12.

In addition, as shown in FIG. 2, the groove 20 is disposed at a position spaced apart from the peripheral surface of the electrode material 12 on the tip surface 11 </ b> A of the electrode base 11, so that the groove 20 and the electrode material 12 are disposed. A wall 11C of the electrode base 11 is formed between the peripheral surface of the electrode base 11 and the peripheral surface.
The hollow portion 11D located at the center of the electrode base 11 of the plasma torch electrode 10 is a space through which cooling water circulates.
With this configuration, the electrode material 12 in the vicinity of the tip surface 11A of the electrode base 11 can be cooled, and it is assumed that molten hafnium is suppressed from flowing into the groove 20.

According to the plasma torch electrode 10 and the plasma torch 1 according to one embodiment, even if hafnium constituting the electrode material 12 melts, it moves and diffuses along the tip surface of the plasma torch electrode 10 to the electrode substrate 11. It is suppressed.
As a result, the mass reduction of hafnium constituting the electrode material 12 is suppressed, and as a result, the life of the plasma torch electrode 10 can be extended.

  Further, according to the plasma torch electrode 10 and the plasma torch 1, the electrode material 12 is disposed in the hole 11 </ b> B located at the center of the tip surface 11 </ b> A of the electrode base 11, and the groove 20 is disposed coaxially with the electrode material 12. Therefore, it is possible to generate a stable plasma arc for a long time, thereby extending the life of the electrode 10 for the plasma torch.

  Further, according to the plasma torch electrode 10 and the plasma torch 1, the groove 20 is formed in a V-groove shape, and the distance in the radial direction can be set large with respect to the depth direction. It is possible to efficiently suppress the diffusion of the constituent hafnium.

Further, according to the observation in the plasma torch electrode 10 in which the ring-shaped groove 20 is arranged coaxially with the electrode material 12 on the tip surface 11A of the electrode base 11, the working gas in the vicinity of the groove 20 is accelerated, and as a result. It is speculated that the working gas flow and the plasma arc are stabilized and heat transfer from the plasma arc to the electrode material 12 is suppressed, so that the melting of hafnium is reduced and the diffusion due to the outflow or scattering of hafnium is reduced. The
Moreover, as a result of suppressing the hafnium constituting the electrode material 12 from melting and diffusing more than necessary, the melting of the electrode base 11 is also suppressed, and the plasma torch electrode 10 as a cathode in the middle of consumption is stabilized. I guess that.

Hereafter, an example of the experimental result which the present inventors implemented is shown.
The plasma torch 1 used has an outer diameter of the tip of the electrode substrate of 7.5 mm in diameter and an outer diameter of the tip of the electrode material of 2.0 mm in diameter. The processing conditions are a current value of 470 A, a cutting speed of 4500 mm / min, and a cutting cycle of 6 minutes. When the workpiece having a plate thickness of 12 mm was cut as / times, the lifetimes of the plasma arc generating electrodes with and without the grooves 20 were compared.
The groove 20 has a diameter of 3 mm coaxially with the center of the electrode material 12, a depth of 0.4 mm, and V-groove processing.
As a result, it was confirmed that the life of 45 minutes with the conventional grooved product was extended to 82 minutes with the grooved product.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
For example, although the case where the electrode material is hafnium has been described in the above embodiment, the electrode material may be made of a high melting point material other than hafnium.

  Moreover, in the said embodiment, although the case where the groove | channel 20 was formed in ring shape was demonstrated, the groove | channel 20 is good also as a planar view polygon, for example, and the space | interval with some electrode materials in the circumferential direction position. May have different dimensions.

Moreover, in the said embodiment, although the groove | channel 20 demonstrated the case where the cross section orthogonal to the extending direction was formed in V shape, for example, a cross section is U shape, semicircle shape, rectangular shape, etc. It is good also as a shape.
In addition, the distance between the axis O of the electrode material 12 and the groove 20 (which can be substituted by the diameter of the groove 20) and the depth may be set and changed without departing from the spirit of the present invention.
Further, the plasma torch may be configured by applying the plasma torch electrode 10 to a nozzle having a structure different from the nozzle 2 shown in the above embodiment.

  According to the plasma torch electrode and the plasma torch according to the present invention, the diffusion of the electrode material to the electrode substrate can be suppressed, so that it can be used industrially.

O axis W work material P plasma arc 1 plasma torch 1A torch main body 2 nozzle 3 working gas passage 2A working gas ejection hole 10 electrode for plasma torch 11 electrode base 11A tip surface 11B hole 12 electrode material

Claims (3)

An electrode for a plasma torch having an electrode base and an electrode material disposed on a tip surface of the electrode base, and generating a plasma arc by applying a current between the electrode material and a workpiece,
The tip surface of the electrode base is formed only on the tip side without having a flow path from the outside, and a V-shaped groove surrounding the electrode material is formed with a space from the electrode material. An electrode for a plasma torch characterized by The plasma torch electrode according to claim 1, wherein
The electrode material is
An electrode for a plasma torch , wherein the electrode is disposed in a hole located in the center of the tip surface of the electrode substrate, and the groove is disposed coaxially with the electrode material . An operation in which a plasma torch electrode is held coaxially with the nozzle in a torch body in which a nozzle for ejecting a working gas is formed at the tip, and is supplied to the nozzle between the torch body and the plasma torch electrode A plasma torch in which a working gas passage through which gas flows is formed,
Plasma torch, characterized in that it comprises a plasma torch electrode according to claim 1 or 2.

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