KR20000015753A - Manufacturing method of electrode for plasma arc cutting torch - Google Patents

Abstract

PURPOSE: A manufacturing method of an electrode for a plasma arc cutting torch is provided to easily mass-produce since a manufacturing process is simple and to save a manufacturing cost. CONSTITUTION: The electrode for the plasma arc cutting torch has the steps of:forming a hole(6) on the upper end of an electrode body(1); making a filler metal having a lower melting point than a middle metal(11), the electrode body and a radiative insert(3) into a power shape(12) or a proper shape fitting to the shape of the hole; processing the filler metal into a tube shape that both sides are punched or a tube shape which is some transformed and then heating; filling between the electrode body and the middle metal, the middle metal and the radioactive insert and the radioactive insert and the electrode body by gravity and a capillary tube event since the filler metal melts.

Description

Manufacturing method of electrode for plasma arc cutting torch

The present invention relates to an electrode of a plasma cutting torch, which is widely used for cutting metals and nonmetals by using the patent application No. 98-31988, which has been previously applied, and more particularly, to a method of manufacturing an electrode having an improved lifetime. A method for producing an electrode for plasma arc cutting torch.

Generally, there are various kinds of thermal cutting used for cutting metal, such as oxygen cutting, plasma cutting, laser cutting, waterjet cutting, and especially, plasma cutting can be applied to a relatively wide range of thickness compared to other cutting methods. Therefore, it is widely used in industrial fields such as shipbuilding, construction, and so on. The torch of such plasma cutting typically includes an electrode that sustains an arc that extends from the electrode to the workpiece in a transfer arc manner. It is also common to surround this arc with a swirling vortex of gas.

However, plasma cutting consumes a lot of components such as electrodes in the cutting torch due to the high heat generated during the cutting. In particular, plasma cutting using air, oxygen, or oxygen mixed gas is a serious problem.

Conventionally, the electrode body 1 is made of copper or copper alloy, which is generally good in heat transferability and conductivity, as shown in FIG. 1, and has a round pipe shape, one of which is an open portion of the electrode body, which is drilled for inflow of cooling water. (9) is formed, and the other part is generally comprised by the structure of the blocked part 5 of an electrode body.

In addition, a radial insert made of a material having a lower work function than that of copper or an alloy of copper, which is the main material of the electrode body 1, is inserted in the blocked portion 5 of the electrode body. The work function is defined as the dislocation step, measured in electron volts, in which thermal ions are released from the surface of the metal at a given temperature. As can be seen in the table below, hafnium, zirconium, and the like, which are commonly used as materials for the spin insert 3, have a low work function compared to copper having a work function of 4.46 eV. Can preferentially emit electrons.

Table 1 below shows the physical properties of some metals related to the present invention.

Table 1

Kinds Melting Point (℃) Work function (eV) Oxidation resistance silver 961 4.73 High resistance gold 1063 4.82 Resistance is very large platinum 1749 5.32 Resistance is very large nickel 1452 5.0 Good resistance hafnium 2207 3.60 - tungsten 3300 4.54 - Copper 1083 4.46 -

However, the problem with the above-mentioned electrode is that the temperature of the ambient atmosphere becomes very high when the plasma arc is sustained in the spin insert 3, in which oxygen contained in the plasma gas is easily formed at the high temperature at the electrode body (copper or copper alloy) around the spin insert. ) To form an oxide.

As a result, the oxidized copper has a sharp drop in work function, causing the arc to be sustained in preference to the spin insert 3, at which time copper oxide and copper are melted and consumed in a shape as shown in FIG. It will shorten the lifespan and lead to premature failure of the electrode.

The electrode developed to solve this problem is a material having a high oxidation resistance, good heat resistance and conductivity between the electrode body 3 and the spin insert 3 as shown in FIG. 3, and a higher work function than the spin insert 3. (For example, silver, gold, platinum, or an alloy thereof), the intermediate metal 2 is made and inserted. Since the intermediate metal 2 physically isolates the spinning insert 3 and the electrode body 1, the intermediate metal 2 prevents the oxidation of the electrode body 1 to some extent in a high temperature atmosphere. Also, since the melting point of the intermediate metal 2 is generally lower than that of the electrode body 1, the melting point is first melted and evaporated to take away the heat of vaporization from the surroundings, resulting in the effect of cooling the electrode body 1.

In addition, this intermediate metal (2) has a high resistance to oxidation thereof, and thus does not have a problem such as a decrease in work function due to oxidation, which frequently occurs in copper or copper alloys, and improves cooling effect due to good heat transfer and conductivity. By doing so, a significant effect on the extension of the electrode life can be expected.

However, in order to make such an electrode, the intermediate metal (2) must be inserted into the electrode body (1), and the spin insert (3) is inserted again among them. By increasing it, the task is not simple.

For this reason, many existing electrodes do not fully exhibit the initial designed functions due to manufacturing problems, or the manufacturing cost is too expensive.

That is, as one of the conventional electrode manufacturing methods, as shown in Fig. 4, a large enough hole 6 into which the radial insert 3 can be inserted into the blocked portion 5 of the whole body is inserted, and hafnium (Hf) is inserted into the hole 6. Or insert the insert (3) made of zirconium (Zr) and pour the molten intermediate metal (4) around it, this method has a good metallurgical bonding strength, but the work method is difficult, and mass There is a limit to production

It is also difficult to match the centerline of the radiation insert 3 and the electrode body 1.

Another manufacturing method conventionally used, as shown in Fig. 5, inserts the radial insert 3 into the tubular intermediate metal 7 with one hole closed and inserts it into the hole 6 of the visible electrode body 1; How to put in.

Even in this manufacturing method, when the electrode body 1, the clogged tube-shaped intermediate metal 7, and the radiation insert 3 are mechanically fitted together without a metallurgical bond to each other, the formation of minute gaps is inevitable.

This gap can deteriorate the conductivity and heat transfer properties, which can ultimately shorten the life of the electrode.

In addition, in order to increase the possible adhesion, high-precision machining must be performed on each part, which leads to difficulty in mass production and an inevitable increase in price.

In addition to this method, if the metallurgical coupling between the electrode body 1, the clogged tube-shaped intermediate metal 7, and the spin insert 3 is performed in the manufacturing process as shown in FIG. 5, a complicated multi-step assembly process is required and the work is difficult. May be limited, mass production will be limited, and price increases will be unavoidable.

The present invention has been made to solve the above problems, the center line of the electrode body and the radiation insert is easy to match, the metallurgical coupling between the electrode body at one time, the manufacturing process is simple, mass production is easy, and production cost It is to provide a method of manufacturing a plasma arc cutting torch electrode that can lower the.

In order to achieve the above object, the present invention drills a hole having a sufficient size and depth in the body of the electrode, and then inserts the filler material in the form of a powder or appropriately processed (for example, a disk, etc.) in the hole, and then Insert the radial insert into the perforated tube-shaped intermediate metal, insert it into the electrode body again, insert the tube-shaped intermediate metal into the electrode body first, and then insert the combined electrode in the state of inserting the radial insert. It is achieved by providing a method of manufacturing an electrode for a plasma arc cutting torch that melts the solvent only by placing it in the furnace) and heating it to a temperature higher than the melting point of the solvent, lower than the melting point of the tube-shaped intermediate metal, and lasting an appropriate time.

1 is an external view of an electrode for cutting oxygen plasma with a conventional intermediate metal

2 is a depleted form of an electrode without a conventional intermediate metal

3 is a cross-sectional structural view of a conventional intermediate metal inserted electrode

Figure 4 is a process diagram of assembling the intermediate metal and the spin insert of the conventional electrode

Figure 5 is another process of assembling the intermediate metal and the spin insert of the conventional electrode

Figure 6 is a process diagram for assembling the intermediate metal and the spin insert to the electrode of the present invention

Figure 7 is another process of assembling the intermediate metal and the spin insert to the electrode of the present invention

8 is a perspective view of the present invention intermediate metal

Figure 9 is another application example of assembling the intermediate metal and the spin insert on the electrode in accordance with the present invention

10 is another application embodiment of the electrode manufacturing method for heating by placing a solvent on the electrode in accordance with the present invention

<Explanation of symbols for main parts of the drawings>

(1): electrode body (2): intermediate metal

(3): spin insert (4): molten intermediate metal

(5): blocked portion of the electrode body (6): hole

(7): Intermediate metal in the form of a tube with one side blocked (8): Consumption of conventional electrodes

(9): open part of the electrode body

(11): intermediate metal in the form of a tube with both sides open

(12): Solvent in powder form

(13): Solvent of appropriate shape for hole shape

(14): tubular solvent with one hole blocked

(15): Assembly view when using tubular intermediate metal

(16): Assembly state when using cylindrical intermediate metal

(17): Solvent placed on electrode to run in furnace

(18) Drills for drilling inserts

Referring to the configuration and operation of the present invention in detail based on the accompanying drawings as follows.

As shown in FIG. 6, a hole 6 having a sufficient size and depth is drilled in the body of the electrode, and the filler material is first formed into a powder form 12 or an appropriately processed form (for example, a disc or the like) in the hole 6. After inserting (13), the radial insert 3 is inserted into the tube-shaped intermediate metal 11 on both sides, and it is inserted into the electrode body again.

Alternatively, the intermediate metal 11 in the shape of a tube in the electrode body 1 may be inserted first and then the radial insert 3 may be inserted in accordance with working convenience.

The electrode thus joined is placed in a furnace and heated to a temperature higher than the melting point of the solubilizers 12 and 13 and lower than the melting point of the tubular intermediate metal 11, and the appropriate time is maintained.

At this time, the filler 12 (13) is melted and maintained for a certain time in the furnace, the gravity between the radial insert and the intermediate metal, the intermediate metal and the electrode body and the electrode body and the spin insert by the capillary phenomenon Will be filled up.

When this is cooled after a certain period of time, the metallurgical bonds are formed when the solvents between these metals harden.

At this time, in order to fill the gap more reliably, the solvent is easily made of metal by continuously pressing the tubular intermediate metal 11 and the radial insert 3 at an appropriate pressure in the direction of the electrode body 1 in the furnace. It is to be able to seep into the gap of the field.

Moreover, it is effective to make the atmosphere of a furnace into a vacuum so that the bubble which may exist in a molten solubilizer can be removed.

After cooling, better finish should be obtained around the spin insert 3 and the intermediate metal 2 of the electrode.

In this case, it is preferable that the filler metal used is a powder form 12 or a suitable form 13 according to the shape of the hole 6 of the electrode body 1, and the melting point should be lower than that of the intermediate metal 11, and generally copper 28 The composition consisting of%, 0.5% nickel and 71.5% silver is effective, but can be changed to an appropriate composition ratio as necessary.

Another manufacturing method is to drill a hole 6 having a sufficient size and length to allow the radial insert 3 and the intermediate metal 11 to enter the body 1 of the electrode as shown in FIG. And inserting the spin insert, the mixed portion 5 of the electrode body 1 faces upward as shown in (17) of FIG. 10, and is heated in a vacuum furnace with a sufficient amount of the solvent 13 placed thereon. .

The temperature in the furnace is set about 20-50 ° C. higher than the melting point of the solvent 13 so that only the solvent 13 is melted without melting other parts of the electrode such as the electrode body, the intermediate metal, and the spin insert. Heat to a possible temperature and then cool.

The molten solubilizer 13, which is placed on the blocked portion 5 of the electrode in the furnace, when the fluidity is improved, the intermediate metal 11, the electrode body 1, and the intermediate portion are formed by the action of capillary shape and gravity. By penetrating down along the gap between the metal 11 and the spin insert 3, a complete metallurgical coupling between these metals occurs.

At this time, in order to maximize the effect of the capillary phenomenon and gravity, the interval between the intermediate metal (2) and the electrode body (1) and the intermediate metal (2) and the radial insert (3) is preferably about 0.1-0.5 mm.

In addition, when the solvent is not sufficiently penetrated into the lower part of the spin insert 3, a small amount of the solvent may be generated in the hole 6 before inserting the spin insert, so that the solvent may occur under the spin insert 3 Can solve the shortage.

In addition, in the various electrode manufacturing methods mentioned above, in addition to the method using the tubular intermediate metal 11, it is also possible to use a hollow cylindrical intermediate metal 19, the electrode body as shown in (16) of FIG. Drill a hole in which the intermediate metal 19 enters into (1), insert the intermediate metal, and then machine a hole into which the spin insert 3 can enter by a machine such as a drill 18, and then insert the spin insert (3). You can also use the method of inserting.

In addition to the metallurgical bonding in the manufacturing process for the metallurgical insert (3) may be plated with gold, silver, platinum, etc., and then the above manufacturing method may be used.

Therefore, the present invention is easy to coincide with the center line of the electrode body and the radiation insert, and the metallurgical coupling between the electrode body at one time, the manufacturing process is simple, mass production is easy, and the manufacturing cost can be lowered, and In another embodiment, the process of drilling a hole in the electrode body and inserting a solvent in the form of a powder or an appropriate shape is the same as in the above invention, but inserts a spin insert directly into the electrode body without an intermediate metal, and then It is also possible to use a method of directly bonding the spin insert and the electrode body by melting the solubilizing agent. The electrode thus manufactured is a very useful invention to simplify the manufacturing process and minimize the cost.

Claims (6)

In the fabrication of a plasma electrode having an intermediate metal (11) between the electrode body (1) and the radiation insert (3); A hole 6 having an appropriate size is formed in the upper end of the electrode body 1, and the melting point of the lower melting point than the intermediate metal 11, the electrode body 1 and the spin insert 3 is formed in powder form 12. Or by inserting it into an appropriate shape (13) suitable for the shape of the hole (6), processing it in the form of a tube with two sides or a slightly deformed tube, and then heating it in a furnace, and melting these solvents. Metallurgy by filling the electrode body (1) and the intermediate metal (11), the intermediate metal (11) and the radiating insert (3), and the radiating insert (3) and the electrode body (1) by gravity and capillary action A method of manufacturing an electrode for a plasma arc cutting torch, characterized in that consisting of a coupling. The method of claim 1; The manufacturing method of the electrode for plasma arc cutting torch which has the manufacturing process of Claim 1, but has no intermediate metal (11), and has a simpler manufacturing process. The method of claim 1; By setting the atmosphere of the heating furnace to vacuum, no bubbles are contained in the molten solvent, and a sufficient time is maintained, so that the solvent is caused by gravity, capillary action, etc. Method for producing an electrode for plasma arc cutting torch, characterized in that to be uniformly filled in the metal (11). The solubilizer is in the form of powder (12) or any shape (13) according to the shape of the hole (6) of the electrode body (1), the melting point of the electrode body (1), the intermediate metal (11) and the spin insert (3) By melting at a temperature lower than at least 100 ℃ more, it is melted in a state of minimizing the influence on other materials to metallurgically combine the electrode body (1), the spin insert (3), the intermediate metal (11) at the same time A method for producing an electrode for plasma arc cutting torch. The components of the solubilizers 12 and 13 are copper (28%), silver (81.5%) and nickel (0.5%), or the ratios appropriately changed as necessary, so that the melting point is the spin insert 3 and the middle. The metal (11), lower than the electrode body (1), melting at the lowest temperature in the furnace, characterized in that the electrode body (1), the intermediate metal (11), the radiation insert (3) metallurgically combine Method for producing an electrode for arc cutting torch. A hole 6 into which the intermediate metal can be inserted is formed in the electrode body 1, the tubular 11 or the cylindrical intermediate metal 19 is first inserted, and the radial insert 3 is inserted into the hole of the intermediate metal 11. And inserting a hole (6) into the intermediate metal (2) and the electrode body (1) into the drill insert (18) before inserting the radial insert (3). By placing the solvent 13 on the clogged portion 5 of the electrode and heating it in a vacuum furnace, the molten solvent is dissolved in the electrode body 1 and the intermediate metal 11 by capillary action and gravity. ) And a method of manufacturing an electrode for a plasma arc cutting torch, which penetrates into a gap between the spin insert (3) and bonds them metallurgically with each other.