WO2021033500A1

WO2021033500A1 - Wire for electric discharge machining and manufacturing method thereof

Info

Publication number: WO2021033500A1
Application number: PCT/JP2020/028851
Authority: WO
Inventors: 吉弘児玉; 利春末永; 章夫田久保; 健史辻
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2019-08-22
Filing date: 2020-07-28
Publication date: 2021-02-25
Also published as: JP2021030352A; TW202110561A; TWI754356B; JP7270164B2

Abstract

A wire for electric discharge machining comprises a tungsten wire including cerium oxide in an amount of 0.2-0.4 wt% (inclusive), and the surface roughness Rz of the tungsten wire is 0.6-2.0 μm (inclusive).

Description

Wire for electric discharge machining and its manufacturing method

The present invention relates to an electric discharge machining wire and a method for manufacturing the same.

Conventionally, a wire electric discharge machine is known as a technique for processing metal or the like into a desired shape. In a wire electric discharge machine, a thin metal wire is used as an electrode wire for electric discharge machining (also referred to as an electric discharge machining wire or a cut wire). Patent Document 1 discloses an electrode wire for electric discharge machining, which contains cerium oxide and is composed of tungsten and unavoidable impurities.

Japanese Patent No. 5734352

The conventional electric discharge machining wire has a problem that the start of electric discharge is delayed and the time required for electric discharge machining becomes long. Further, it is required that the electric discharge machining wire itself is less likely to be broken.

Therefore, an object of the present invention is to provide a wire for electric discharge machining and a method for manufacturing the same, which is less likely to cause disconnection during electric discharge machining and can shorten the time required for electric discharge machining.

In order to achieve the above object, the electric discharge machining wire according to one aspect of the present invention includes a tungsten wire containing cerium oxide in a content of 0.2 wt% or more and 0.4 wt% or less, and the surface of the tungsten wire is provided. The roughness Rz is 0.6 μm or more and 2.0 μm or less.

Further, the method for manufacturing an electric discharge machining wire according to one aspect of the present invention is a method for manufacturing an electric discharge machining wire including a tungsten wire containing a cerium oxide, which is a drawing step for drawing the tungsten wire and a drawing step. The electrolytic discharge rate in the electrolytic step is 6% or more and 11% or less, including the subsequent electrolytic step of electrolyzing the tungsten wire.

According to the present invention, it is possible to provide a wire for electric discharge machining and a method for manufacturing the same, which is less likely to cause disconnection during electric discharge machining and can shorten the time required for electric discharge machining.

It is a flowchart which shows the manufacturing method of the electric discharge machining wire which concerns on embodiment.

In the following, the electric discharge machining wire and the manufacturing method thereof according to the embodiment of the present invention will be described in detail with reference to the drawings. In addition, all the embodiments described below show a specific example of the present invention. Therefore, the numerical values, shapes, materials, components, arrangement and connection forms of the components, steps, the order of steps, etc. shown in the following embodiments are examples, and are not intended to limit the present invention. Therefore, among the components in the following embodiments, the components not described in the independent claims will be described as arbitrary components.

(Embodiment)
[Production method]
First, a method of manufacturing an electric discharge machining wire according to the present embodiment will be described with reference to FIG. FIG. 1 is a flowchart showing a method of manufacturing an electric discharge machining wire according to the present embodiment.

As shown in FIG. 1, first, an ingot containing cerium oxide and tungsten is prepared (S10). Specifically, an aggregate of cerium oxide-doped tungsten powder (hereinafter referred to as doped tungsten powder) is prepared by mixing an aqueous solution of cerium nitrate and a tungsten powder. The mass ratio of the cerium nitrate aqueous solution and the tungsten powder is adjusted so that the content of the cerium oxide in the produced tungsten wire is 0.2 wt% or more and 0.4 wt% or less. An ingot is prepared by pressing and sintering (sintering) the aggregate of the doped tungsten powder. The average particle size of the tungsten powder is, for example, in the range of 3 μm or more and 4 μm or less.

The method of preparing an ingot containing cerium oxide and tungsten is not limited to the method of using an aqueous solution of cerium nitrate. For example, an ingot may be produced by pressing and sintering a mixture of tungsten powder and cerium oxide powder.

Next, the produced ingot is subjected to aging processing (S12). Specifically, a wire-shaped tungsten wire is formed by forging, compressing, and stretching the ingot from the surroundings. In addition, you may perform rolling processing instead of aging processing.

For example, by repeating the aging process, an ingot having a diameter of about 15 mm or more and about 25 mm or less is formed into a tungsten wire having a wire diameter of about 3 mm. By performing the annealing treatment in the process during the aging process, the workability in the subsequent process is ensured. For example, an annealing treatment at 2400 ° C. is carried out in a range of 8 mm or more and 10 mm or less in diameter. However, in order to improve the tensile strength by refining the crystal grains, the annealing treatment is not performed in the aging step having a diameter of less than 8 mm.

Next, draw a tungsten wire (S14). Specifically, first, the tungsten wire is heated to form an oxide layer on the surface. For example, the tungsten wire is directly heated using a burner or the like at a heating temperature of 900 ° C. By forming the oxide layer on the surface, it is possible to suppress the occurrence of disconnection in the subsequent drawing process.

In the drawing step (S14), the tungsten wire is heated and drawn using one drawing die. That is, the drawing (thinning) of the tungsten wire is performed while heating. The heating wire drawing is repeated while exchanging the wire drawing die. The cross-sectional reduction rate of the tungsten wire by one heating drawing using one wire drawing die is, for example, 10% or more and 40% or less. For heating delineation, a lubricant in which graphite is dispersed in water may be used.

In repeating the heating wire drawing, a wire drawing die having a smaller hole diameter than the wire drawing die used in the immediately preceding heating wire drawing is used. Further, as the number of repetitions increases, the heating temperature is lowered. That is, in the heating wire drawing using a small wire drawing die, the heating temperature is lowered as compared with the heating wire drawing using a large wire drawing die. In addition, electrolysis may be performed in the middle of the repetition of heating and drawing. The wire drawing dies used are carbide dies up to a wire diameter of 0.38 mm, sintered diamond dies in the wire diameter range of 0.38 mm to 0.18 mm, and single crystals in the wire diameter range of 0.18 mm to 0.020 mm. Use a diamond die.

By performing the heating wire drawing process, a tungsten wire having a wire diameter substantially equal to the wire diameter required for electric discharge machining wire can be obtained.

After the drawing process, the tungsten wire is electrolyzed (S16). Specifically, a voltage is applied between the tungsten wire and the counter electrode in a state where the drawn tungsten wire and the counter electrode are immersed in an electrolytic solution such as an aqueous potassium hydroxide solution. As a result, the surface of the tungsten wire is polished, so that oxides and graphite adhering to the surface can be removed. Therefore, the wire diameter of the tungsten wire after electrolysis is smaller than the wire diameter of the tungsten wire before electrolysis.

In the present embodiment, the electrolysis rate in the electrolysis step is 6% or more and 11% or less. The electrolysis rate is the ratio of the mass lost by the tungsten wire in the electrolysis step to the mass of the tungsten wire before electrolysis. The larger the electrolysis rate, the greater the amount of decrease in the diameter of the tungsten wire. When the wire diameter of the tungsten wire after electrolysis is, for example, 50 μm, when the tungsten wire having a large wire diameter is electrolyzed, the electrolysis rate in the electrolysis step becomes large.

In the present embodiment, the electrolysis rate is made smaller than before, so that the surface of the tungsten wire has irregularities. Specifically, the surface roughness Rz of the surface of the tungsten wire is set to 0.6 μm or more and 2.0 μm or less. The unevenness is specifically a die mark formed by a wire drawing die. The die mark is a long groove extending along the axial direction of the tungsten wire.

Through the above steps, the tungsten wire according to this embodiment is manufactured. By going through the above manufacturing process, the length of the tungsten wire immediately after manufacturing is, for example, 50 km or more, and it can be industrially used. The tungsten wire can also be cut to an appropriate length depending on the mode in which it is used and used in the form of a needle or rod.

Note that each step shown in the method for manufacturing a tungsten wire is performed in-line, for example. Specifically, the plurality of wire drawing dies used in step S14 are arranged on the production line in the order of decreasing hole diameter. In addition, a heating device such as a burner is arranged between the wire drawing dies. An electrolyzer is arranged on the downstream side of the wire drawing die used in the final wire drawing process. In addition, each step may be performed individually.

[Wire for electric discharge machining]
Subsequently, the electric discharge machining wire according to the present embodiment will be described.

The electric discharge machining wire includes a tungsten wire containing tungsten as a main component. The tungsten wire contains cerium oxide and tungsten. The tungsten wire may contain unavoidable impurities. The unavoidable impurities are substances that are unavoidably mixed in the raw material of the tungsten wire and in the manufacturing process of the tungsten wire, and mean substances that are not intentionally mixed. The tungsten wire is manufactured, for example, by the manufacturing method described with reference to FIG. In this embodiment, the tungsten wire itself is an electric discharge machining wire.

<Content rate>
The content of cerium oxide in the tungsten wire is 0.2 wt% or more and 0.4 wt% or less. The content of cerium oxide may be 0.26 wt% or more and 0.30 wt% or less. The content of cerium oxide is the ratio of the mass of cerium oxide to the total mass of the tungsten wire. The same applies to the content of other substances such as tungsten and unavoidable impurities.

Specifically, the cerium oxide is CeO ₂ (cerium (IV) oxide). The cerium oxide may contain Ce ₂ O ₃ (cerium (III) oxide).

When the content of cerium oxide is 0.2 wt% or more, the amount of current flowing through the tungsten wire (electric discharge machining wire) during electric discharge machining can be reduced. As a result, it is possible to suppress an increase in wire temperature during electric discharge machining. When the wire temperature rises, the tensile strength of the tungsten wire decreases, so that disconnection is likely to occur. In the tungsten wire according to the present embodiment, since the decrease in tensile strength is suppressed, the occurrence of disconnection is also suppressed. As the content of cerium oxide becomes larger than 0.2 wt%, the amount of current during electric discharge machining can be further suppressed, and the temperature rise can be further suppressed.

Further, when the content of cerium oxide is 0.4 wt% or less, it is possible to ensure the ease of processing (specifically, thinning) the tungsten wire. Further, when the content of the cerium oxide is 0.4 wt% or less, the high temperature strength characteristic of tungsten makes it strong against a high temperature state and makes it difficult for disconnection to occur during electric discharge machining. The smaller the content of cerium oxide is less than 0.4 wt%, the more the occurrence of disconnection can be suppressed.

The content of tungsten in the tungsten wire is 99.6 wt% or more and 99.8 wt% or less. The content of tungsten may be 99.7 wt% or more and 99.74 wt% or less. Since the tungsten wire may contain unavoidable impurities, the tungsten content may be less than 99.6 wt%. For example, the content of unavoidable impurities may be 0.1 wt% or less, and the content of tungsten may be 99.5 wt% or more.

<Wire diameter>
The wire diameter of the tungsten wire is, for example, 20 μm or more and 100 μm or less. The wire diameter of the tungsten wire may be 80 μm or less, 70 μm or less, 60 μm or less, 50 μm or less, 40 μm or less, or 30 μm or less.

In the present embodiment, since the wire diameter of the tungsten wire is 100 μm or less, fine machining in electric discharge machining becomes possible. As the diameter of the tungsten wire becomes smaller than 100 μm, finer processing is realized.

Further, when the diameter of the tungsten wire is 20 μm or more, the discharge can be stably performed. The larger the diameter of the tungsten wire is, the more stable the discharge can be.

<Cross-sectional shape>
The shape of the cross section orthogonal to the line axis direction of the tungsten wire is, for example, circular. Alternatively, the cross-sectional shape of the tungsten wire may be elliptical, square or rectangular.

<Straightness>
The straightness of the tungsten wire is represented by the natural hanging length of the tungsten wire having a length of 1000 mm. The straightness of the tungsten wire according to this embodiment is 950 mm or more. The straightness of the tungsten wire may be 990 mm or more, or 995 mm or more. The straightness may be represented by the natural hanging length of a tungsten wire having a length of 500 mm.

When the straightness is 950 mm or more, the setting to the electric discharge machine becomes easy, and the occurrence of disconnection at the time of setting can be suppressed. The higher the straightness is than 950 mm, the easier the setting to the electric discharge machine is, and the occurrence of disconnection at the time of setting can be further suppressed.

<Tensile strength>
The tensile strength of the tungsten wire at 20 ° C. is 3500 MPa or more. The tensile strength of the tungsten wire may be 3800 MPa or more, or 4000 MPa or more. The tensile strength of the tungsten wire may be 4200 MPa or more, 4500 MPa or more, 4800 MPa or more, or 5000 MPa or more. In addition, in this specification, "tensile strength" means the tensile strength at 20 degreeC unless otherwise specified.

When the tensile strength is 3500 MPa or more, the setting to the electric discharge machine becomes easy, and the occurrence of disconnection at the time of setting can be suppressed. In addition, it is possible to suppress the occurrence of disconnection during electric discharge machining. As the tensile strength becomes higher than 3500 MPa, the occurrence of disconnection during setting and electric discharge machining can be further suppressed.

<Surface roughness Rz>
The surface roughness Rz of the tungsten wire is 0.6 μm or more and 2.0 μm or less. The surface roughness Rz may be 0.6 μm or more and 1.5 μm or less. Alternatively, the surface roughness Rz may be 0.7 μm or more and 1.2 μm or less. The surface roughness Rz is the maximum height of surface irregularities defined by JIS B 0601-2001 (Non-Patent Document). The surface roughness Rz is the surface roughness of the outer peripheral side surface around the line axis of the tungsten wire. The surface roughness of the end faces at both ends in the axial direction of the tungsten wire is not particularly limited.

When the surface roughness Rz is 0.6 μm or more, electric discharge is likely to be started on the surface of the electric discharge machining wire. As the surface roughness Rz becomes larger than 0.6 μm, the electric discharge is more likely to be started, so that the time required for the electric discharge machining to be started can be shortened. When the electric discharge machining wire is brought close to the work (that is, the object to be machined by the electric discharge machine), the electric field tends to concentrate between the portion of the electric discharge machining wire having a large surface roughness Rz and the work, resulting in electric discharge. It is presumed that this is easy to do.

On the other hand, if the surface roughness Rz is too large, disconnection is likely to occur during electric discharge machining. On the other hand, when the surface roughness Rz of the tungsten wire according to the present embodiment is 2.0 μm or less, the occurrence of disconnection can be suppressed. The smaller the surface roughness Rz is than 2.0 μm, the less likely it is that disconnection will occur.

As described above, the tungsten wire according to the present embodiment is less likely to be broken during electric discharge machining, and the time required for electric discharge machining can be shortened.

The surface roughness Rz of the tungsten wire corresponds to the size of the die mark given by the wire drawing die used in the drawing process. The size of the die mark depends on the electrolysis rate in the electrolysis process after drawing. That is, as the electrolysis rate increases, the residual die marks decrease, the surface of the tungsten wire becomes smooth, and the surface roughness Rz decreases. The smaller the electrolysis rate, the more the die marks remain, and the unevenness on the surface of the tungsten wire remains, and the surface roughness Rz increases. In the present embodiment, the surface roughness Rz can be set in the range of 0.6 μm or more and 2.0 μm or less by setting the electrolysis rate in the electrolysis step to 6% or more and 11% or less.

[Example]
Subsequently, a comparative example and an example of the electric discharge machining wire will be described.

<Electrolysis conditions>
Table 1 below shows the electrolysis conditions of the samples according to Comparative Examples and Examples.

The black wire in Table 1 is a tungsten wire immediately after drawing and before electrolysis. MG is a numerical value expressing the mass of a tungsten wire having a length of 200 mm in milligrams. In the case of pure tungsten ^{wire, the relationship of MG = 3016 × D 2} (D is the wire diameter) is satisfied.

The conditions for satisfying the electrolysis rate are different between the samples according to Comparative Examples 1 and 2 and the samples according to Examples 1 to 4. Specifically, the samples according to Examples 1 to 4 satisfy the range of the electrolysis rate of 6% or more and 11% or less, whereas the samples according to Comparative Examples 1 and 2 satisfy the range. Absent. Electrolysis was performed three times by applying an AC voltage.

In the samples according to Comparative Example 1 and Examples 1 to 4, the MG (wire diameter) of the black wire was adjusted so that the wire diameter of the tungsten wire after electrolysis was in the range of 50 μm ± 0.5 μm. Further, in the sample according to Comparative Example 2, the MG of the black wire was adjusted so that the wire diameter of the tungsten wire after electrolysis was in the range of 100 μm ± 1 μm.

The steps up to the production of the black wire (that is, steps S10 to S14 shown in FIG. 1) are substantially the same in Comparative Examples and Examples. The difference between the comparative example and the embodiment is that the hole diameter of the drawing die used in the final drawing step is different in order to adjust the MG of the black wire. Further, as shown in Table 3, in the samples according to Comparative Example 1 and Examples 1 to 4, tungsten powder and nitrate were prepared so that the content of cerium oxide contained in the produced tungsten wire was about 0.3 wt%. While the mixing ratio with the cerium aqueous solution was adjusted, in the sample according to Comparative Example 2, the mixing ratio was adjusted so that the content of the cerium oxide was less than 0.1 wt%.

<Characteristic value of tungsten wire>
Tables 2 and 3 show the measurement results of the characteristic values of each sample produced based on the conditions shown in Table 1, respectively.

The depth of the dice mark in Table 2 shows the results measured at three points A to C on the surface of the sample and their average values. Here, the maximum depth of the three points in each sample is regarded as the surface roughness Rz.

As shown in Table 2, in the sample according to Comparative Example 1, the surface roughness Rz was less than 0.6 μm. In the samples according to Comparative Example 2 and Examples 1 to 4, the surface roughness Rz was in the range of 0.6 μm or more and 2.0 μm or less.

As shown in Table 3, in the samples according to Comparative Example 1 and Examples 1 to 4, the average value of MG, the tensile strength, the straightness, and the content of cerium oxide are substantially equal to each other. The sample according to Comparative Example 2 is substantially the same as the other samples in terms of straightness. The average value of MG and the content of cerium oxide are different values depending on the difference in production conditions.

<Processing results by electric discharge machine>
The samples according to each Comparative Example and each Example were set in an electric discharge machine as a wire for electric discharge machining, and the work was actually cut.

The electric discharge machine is an NC electric discharge wire cutting machine (AP200L manufactured by Sodick Co., Ltd.). The work to be processed is a 9 mm square SKD11. The feed rate of the wire is 9 m / min.

Table 4 shows the results of whether or not the wire can be set for the electric discharge machine and whether or not the work can be cut.

In Table 4, "○" means that the wire setting for the electric discharge machine or the work cutting was performed well. "X" means that the wire was broken in the middle of cutting the work.

As shown in Table 4, both the samples according to the comparative example and the example could be appropriately set in the electric discharge machine.

On the other hand, when the samples according to Comparative Examples 1 and 2 were used as wires for electric discharge machining, the work could not be cut. Specifically, in the samples according to Comparative Examples 1 and 2, the discharge did not start until the sample (wire) and the work were sufficiently close to each other, and a part of the wire became a work due to the influence of heat generated by the current flowing through the wire. Welded and the wire was broken.

When the samples according to Examples 1 to 4 were used as electric discharge machining wires, the workpiece could be cut without breaking the wires. Specifically, in the samples according to Examples 1 to 4, the discharge was started in a state where the wire and the work were separated from each other as compared with the sample according to the comparative example. As a result, the work could be appropriately cut without welding of the wire and the work and without disconnection. Since the time required to start the electric discharge was also shortened, the time required for the electric discharge machining could be shortened.

In the sample according to Comparative Example 1, as shown in Table 3, the content of cerium oxide was contained in the range of 0.2 wt% or more and 0.4 wt% or less, while the surface was as shown in Table 2. The roughness Rz is less than 0.6 μm. Further, in the sample according to Comparative Example 2, as shown in Table 2, the surface roughness Rz is included in the range of 0.6 μm or more and 2.0 μm or less, while as shown in Table 3, the cerium oxide is contained. The content of is less than 0.2 wt%.

On the other hand, in the samples according to Examples 1 to 4, as shown in Tables 2 and 3, the surface roughness Rz is included in the range of 0.6 μm or more and 2.0 μm or less, and the cerium oxide is contained. Is included in the range of 0.2 wt% or more and 0.4 wt% or less. Therefore, based on the results shown in Table 4, since both the surface roughness Rz and the content of the cerium oxide are included in the above range, disconnection is unlikely to occur during the electric discharge machining, and the electric discharge machining is required. It turns out that the time can be shortened.

The case where the cerium oxide content is 0.26 wt% or more and 0.30 wt% or less is shown as an example, but the case where the cerium oxide content is 0.20 wt% or more and less than 0.26 wt%, and It has been confirmed that even in the case of greater than 0.30 wt% and 0.40 wt% or less, wire setting and work cutting are performed satisfactorily as in the above embodiment. Similarly, regarding the surface roughness Rz, the case where the surface roughness of the tungsten wire is about 0.9 μm or more and about 1.5 μm or less is shown as an example, but the surface roughness of the tungsten wire is 0.6 μm or more and 0.9 μm or more. It has been confirmed that the wire setting and the work cutting are performed well in the following cases and in the case of 1.5 μm or more and 2.0 μm or less as in the above embodiment.

[Effects, etc.]
As described above, the electric discharge machining wire according to the present embodiment includes a tungsten wire containing cerium oxide in a content of 0.2 wt% or more and 0.4 wt% or less. The surface roughness Rz of the tungsten wire is 0.6 μm or more and 2.0 μm or less.

As a result, disconnection is less likely to occur during electric discharge machining, and the time required for electric discharge machining can be shortened.

Further, for example, the wire diameter of the tungsten wire is 20 μm or more and 100 μm or less.

This makes it possible to realize fine processing.

Further, for example, the method for manufacturing an electric discharge machining wire according to the present embodiment is a method for manufacturing an electric discharge machining wire including a tungsten wire containing a cerium oxide, and includes a wire drawing step for drawing a tungsten wire and a wire drawing. It includes an electrolytic step of electrolyzing the tungsten wire after that. The electrolysis rate in the electrolysis step is 6% or more and 11% or less.

As a result, it is possible to realize a wire for electric discharge machining, which is less likely to cause disconnection during electric discharge machining and can shorten the time required for electric discharge machining.

Further, for example, the tungsten wire contains cerium oxide at a content of 0.2 wt% or more and 0.4 wt% or less.

As a result, the current value of the current flowing through the wire during electric discharge machining can be lowered, so that the temperature rise of the wire can be suppressed and the occurrence of wire breakage can be suppressed.

(Other)
The electric discharge machining wire and the method for manufacturing the electric discharge machining wire according to the present invention have been described above based on the above-described embodiment, but the present invention is not limited to the above-described embodiment.

For example, the tungsten wire may contain a substance intentionally mixed in addition to the cerium oxide. For example, the tungsten wire may contain rhenium, and the alloy wire of rhenium and tungsten (that is, the rhenium-tungsten alloy wire) may contain cerium oxide. The rhenium content in this case is, for example, 0.1 wt% or more and 10 wt% or less.

Alternatively, the tungsten wire may contain potassium, and the potassium-doped tungsten wire (that is, the potassium-doped tungsten wire) may contain cerium oxide. The potassium content in this case is, for example, 0.003 wt% or more and 0.008 wt% or less.

Further, for example, the method of reducing the surface roughness Rz of the tungsten wire to 0.6 μm or more and 2.0 μm or less may be performed other than the adjustment of the electrolysis rate in the electrolysis step. For example, the surface roughness Rz may be set to 0.6 μm or more and 2.0 μm or less by producing a tungsten wire having a surface roughness Rz of less than 0.6 μm and then roughening the surface with a chemical agent. That is, the electrolysis rate in the electrolysis step may be a value larger than 11%, and the surface roughness Rz of the tungsten wire immediately after electrolysis may be less than 0.6 μm. Further, the electrolysis rate in the electrolysis step may be less than 6%.

Further, for example, the electric discharge machining wire may be composed of only the tungsten wire according to the above embodiment, or may include a tungsten wire and a thin film formed on the surface of the tungsten wire. For example, a thin film such as an oxide film may be formed on the surface of the tungsten wire. The thin film is formed so as to follow the uneven shape of the surface of the tungsten wire, and the surface roughness Rz of the thin film is equivalent to the surface roughness Rz of the tungsten wire.

Further, for example, in the above embodiment, an example in which the electric discharge machining wire is used for cutting a work is shown, but the present invention is not limited to this. The electric discharge machining wire may be used for partial cutting of workpieces, or may be used for welding two or more workpieces.

Further, for example, the tungsten wire according to the above embodiment may be used for applications other than electric discharge machining. For example, one aspect of the present invention may be a tungsten product comprising the tungsten wire according to the above embodiment. Tungsten products include, for example, saw wires, medical device components (eg, catheters), stranded wires or ropes.

In addition, it is realized by arbitrarily combining the components and functions in each embodiment within the range obtained by applying various modifications to each embodiment and the gist of the present invention. Forms are also included in the present invention.

Claims

A tungsten wire containing cerium oxide in a content of 0.2 wt% or more and 0.4 wt% or less is provided.
A wire for electric discharge machining in which the surface roughness Rz of the tungsten wire is 0.6 μm or more and 2.0 μm or less.
The electric discharge machining wire according to claim 1, wherein the tungsten wire has a wire diameter of 20 μm or more and 100 μm or less.
A method for manufacturing an electric discharge machining wire including a tungsten wire containing a cerium oxide.
The wire drawing process for drawing the tungsten wire and
Including an electrolysis step of electrolyzing the tungsten wire after drawing.
A method for manufacturing an electric discharge machining wire, wherein the electrolysis rate in the electrolysis step is 6% or more and 11% or less.
The method for manufacturing an electric discharge machining wire according to claim 3, wherein the tungsten wire contains the cerium oxide in a content of 0.2 wt% or more and 0.4 wt% or less.