阅读说明：本技术 钨线及钨产品 (Tungsten wire and tungsten product ) 是由 金泽友博 神山直树 井口敬宽 仲井唯 于 2020-04-13 设计创作，主要内容包括：钨线(10)为由钨或钨合金形成的钨线,钨线(10)的线径D为100μm以下,将钨线(10)的断裂张力的50％的张力作为负载施加时的每50mm的扭转断裂转数为250×exp(-0.026×D)次以上。(The tungsten wire (10) is formed of tungsten or a tungsten alloy, the wire diameter D of the tungsten wire (10) is 100 [ mu ] m or less, and the number of torsional fracture turns per 50mm when a tension of 50% of the fracture tension of the tungsten wire (10) is applied as a load is 250 x exp (-0.026 x D) or more.)

1. A tungsten wire is formed of tungsten or a tungsten alloy,

the wire diameter D of the tungsten wire is less than 100 mu m,

the number of torsional breaking turns per 50mm when a tension of 50% of the breaking tension of the tungsten wire is applied as a load is 250 Xexp (-0.026 XD) or more.

2. The tungsten wire of claim 1,

the tensile strength of the tungsten wire is 4800MPa or more.

3. The tungsten wire according to claim 1 or 2,

the tungsten content of the tungsten wire is 90 wt% or more.

4. A tungsten product comprising the tungsten wire according to any one of claims 1 to 3.

5. The tungsten product of claim 4, wherein the tungsten product is a saw wire, a stranded wire, a rope, or a medical device component.

Technical Field

The invention relates to a tungsten wire and a tungsten product.

Background

In recent years, tungsten wires having high tensile strength have been developed (see, for example, patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 6249319

Disclosure of Invention

Problems to be solved by the invention

However, the conventional tungsten wire has a problem that the strength when torsion is applied is insufficient.

Accordingly, an object of the present invention is to provide a tungsten wire and a tungsten product having a higher breaking strength against twisting than before.

Means for solving the problems

In order to achieve the above object, a tungsten wire according to an embodiment of the present invention is a tungsten wire made of tungsten or a tungsten alloy, wherein a wire diameter D of the tungsten wire is 100 μm or less, and a number of times of torsional fracture rotation per 50mm when a tension of 50% of a fracture tension of the tungsten wire is applied as a load is 250 × exp (-0.026 × D) or more.

Further, a tungsten product according to an embodiment of the present invention includes the tungsten wire.

Effects of the invention

According to the present invention, a tungsten wire and a tungsten product having a higher breaking strength against twisting than before can be provided.

Drawings

Fig. 1 is a schematic perspective view of a tungsten wire of an embodiment.

Fig. 2 is a graph showing the results of measurement of the relationship between the tensile strength and the number of torsional fracture rotations of the tungsten wire in examples and comparative examples.

Fig. 3 is a graph showing the measurement results of the relationship between the wire diameter and the number of torsional fracture turns of the tungsten wire in the examples and comparative examples.

Fig. 4 is a flowchart showing a method of manufacturing a tungsten wire according to an embodiment.

Fig. 5 is a diagram showing the heating temperature in the drawing step included in the method for manufacturing a tungsten wire according to the embodiment.

Fig. 6 is a perspective view showing a cutting device including a saw wire as an example of a tungsten product according to an embodiment.

Fig. 7 is a perspective view showing a part of a stranded wire as an example of a tungsten product of the embodiment.

Fig. 8 is a perspective view showing a part of a rope as an example of a tungsten product of the embodiment.

Fig. 9 is a perspective view showing a part of a duct as an example of a tungsten product of the embodiment.

Detailed Description

Hereinafter, a tungsten wire and a tungsten product according to an embodiment of the present invention will be described in detail with reference to the drawings. The embodiments described below are all specific examples of the present invention. Therefore, the numerical values, shapes, materials, constituent elements, arrangement and connection modes of the constituent elements, manufacturing steps, and the order of the manufacturing steps shown in the following embodiments are merely examples, and do not limit the scope of the present invention. Therefore, among the components in the following embodiments, components that are not recited in the independent claims are described as optional components.

The drawings are schematic and not necessarily strictly illustrated. Therefore, for example, the scales and the like in the respective drawings are not necessarily uniform. In the drawings, substantially the same components are denoted by the same reference numerals, and redundant description is omitted or simplified.

In the present specification, a term indicating a relationship between elements such as a vertical or uniform term, a term indicating a shape of an element such as a circle or a rectangle, and a numerical range do not mean only a strict meaning, but also mean a range substantially equivalent to each other, for example, a difference of about several percent.

(embodiment mode)

[ tungsten wire ]

First, the structure of the tungsten wire of the embodiment will be described.

Fig. 1 is a schematic perspective view of a tungsten wire 10 according to the present embodiment. Fig. 1 shows an example in which a tungsten wire 10 is wound around a core material for winding, and further, a part of the tungsten wire 10 is schematically shown in an enlarged manner.

The tungsten wire 10 is formed of tungsten (W) or a tungsten alloy. The tungsten content in the tungsten wire 10 is, for example, 90 wt% or more. The content of tungsten may be 95 wt% or more, or 99 wt% or more. The tungsten content may be 99.9 wt% or more, or 99.95 wt% or more. The tungsten content is a ratio of the weight of tungsten contained in the tungsten wire 10 to the weight of the tungsten wire 10. The same applies to the content of other metal elements such as rhenium (Re) and potassium (K) described later. The tungsten wire 10 may contain inevitable impurities that are inevitably mixed in during manufacture.

The tungsten alloy is, for example, an alloy of rhenium and tungsten (rhenium-tungsten alloy (ReW alloy)). The higher the content of rhenium, the higher the strength of the tungsten wire 10 can be. If the content of rhenium is too high, the workability of the tungsten wire 10 is deteriorated, and it becomes difficult to thin the tungsten wire 10.

In the present embodiment, the rhenium content in the tungsten wire 10 is 0.1 wt% or more and 10 wt% or less. For example, the rhenium content may be 0.5 wt% or more and 5 wt% or less. For example, the content of rhenium is 1 wt%, but may be 3 wt%.

The wire diameter D of the tungsten wire 10 is 100 μm or less. The wire diameter D may be 80 μm or less, 60 μm or less, or 40 μm or less. The wire diameter D may be 30 μm or less, or 20 μm or less. The wire diameter D may be 10 μm or less. The wire diameter D is, for example, 5 μm or more.

In the present embodiment, the wire diameter D of the tungsten wire 10 is uniform. The uniformity may not be complete, and when the film advances in the axial direction, a difference of about a few percent, such as 1%, may be included depending on the location. The cross-sectional shape of the tungsten wire 10 in a cross section perpendicular to the bobbin P is, for example, circular. The cross-sectional shape may be square, rectangular, elliptical, or the like.

The tensile strength of the tungsten wire 10 is 4800MPa or more. The tensile strength of the tungsten wire 10 may be 5000MPa or more, or 5300MPa or more. By adjusting the wire diameter D, the size of tungsten crystal grains, and the like, the tungsten wire 10 having a tensile strength exceeding 5500MPa can be realized. The tensile strength of the tungsten wire 10 may be less than 4800 MPa.

The elastic modulus of the tungsten wire 10 is 350GPa or more and 450GPa or less. Here, the elastic modulus is a longitudinal elastic modulus. In addition, the elastic modulus of the piano wire is generally in the range of 150GPa to 250 GPa. That is, the tungsten wire 10 has an elastic modulus about 2 times that of the piano wire.

The tungsten wire 10 is less likely to be deformed by the elastic modulus of 350GPa or more. That is, the tungsten wire 10 is hard to elongate. On the other hand, by setting the elastic modulus to 450GPa or less, the tungsten wire 10 can be deformed when a force of a certain degree of strength is applied. Specifically, since the tungsten wire 10 can be bent, for example, when used as a saw wire, the tungsten wire can be easily wound around a guide roller or the like.

The tungsten wire 10 of the present embodiment has a characteristic of having a larger number of torsional breaking turns than the conventional one. Hereinafter, the number of torsional breaking rotations will be described.

[ torsional breaking revolution ]

The number of torsional fracture rotations is the number of torsional rotations required until the tungsten wire 10 fractures when a torsion is applied to the tungsten wire 10. The larger the number of torsional fracture turns, the higher the strength of the tungsten wire 10 against torsion.

The number of torsional breaking revolutions was measured by performing a torsion test. The torsion test was performed using the tungsten wire 10 cut out to a predetermined length L. Specifically, both ends of the tungsten wire 10 having the length L in the axial direction are gripped, and a predetermined tension T is applied to the tungsten wire 10 as a load. One end of the tungsten wire 10 is fixed and the other end is rotated around the bobbin while a predetermined tension T is applied. The other end turns around the spool at the number of twisted turns N. The rotation, i.e., twisting, of the other end of the tungsten wire 10 is continued until the tungsten wire 10 breaks. The number of torsional rotation N at the time of breakage of the tungsten wire 10 is the number of torsional breakage rotations.

The present inventors produced a plurality of samples (examples) of the tungsten wire 10 based on the manufacturing method described later, and performed a torsion test to measure the torsional rupture strength of each sample of the examples. Further, samples of comparative examples were also produced, and the torsional breaking strength of each sample of comparative example was measured by performing a torsion test. The samples of the comparative examples were manufactured using a different manufacturing method from the samples of the examples. Differences in the production methods of the examples and comparative examples will be described later.

The length L of the sample used for the torsion test was 50 mm. The tension T is 50% of the breaking tension of the tungsten wire. Here, the breaking tension of the tungsten wire is a tension at the time of breaking the tungsten wire when the tension is applied without twisting the tungsten wire 10 having the length L. The breaking tension of the tungsten wire is, for example, 4N to 10N.

In addition, each sample was a tungsten-rhenium alloy wire. The content of rhenium was 1 wt%, and the content of tungsten was 99 wt%.

Fig. 2 is a graph showing the results of measurement of the relationship between the tensile strength and the number of torsional fracture rotations of the tungsten wire in examples and comparative examples. In fig. 2, the horizontal axis represents the tensile strength of the tungsten wire 10, and the vertical axis represents the number of torsional fracture revolutions of the tungsten wire 10. In fig. 2, the tensile strength of each sample is shown by a plot of black dots (example) or white circles (comparative example). The wire diameter D of each sample was 50 μm.

As shown in fig. 2, the tensile strength of the sample of the example was in the range of about 4700MPa or more and about 5300MPa or less. The tensile strength of the samples of the comparative examples was about 4300MPa or more and less than about 4800 MPa.

As shown in fig. 2, in the sample of the comparative example, the number of torsional breaking revolutions was less than 30 times regardless of the tensile strength. On the other hand, in the samples of examples, the number of torsional breaking revolutions was 70 or more. Samples with a number of torsional breaking revolutions of 200 were also obtained. In any of the samples from the sample having a tensile strength of about 4750MPa to the sample having a tensile strength of about 5200MPa, the number of torsional fracture revolutions was 2 times or more as compared with the sample of the comparative example.

Further, the present inventors produced samples having different wire diameters D in examples and comparative examples. For example, the tensile strength of the sample of the example when the wire diameter D is 30 μm is in the range of about 4800MPa or more and about 5800MPa or less. For example, the tensile strength of the sample of the comparative example is about 3700MPa or more and less than 4800MPa when the wire diameter D is 30 μm.

The inventors of the present application measured the relationship between the wire diameter D and the number of torsional fracture turns. The measurement results are shown in FIG. 3.

Fig. 3 is a graph showing the measurement results of the relationship between the wire diameter D and the number of torsional fracture rotations of the tungsten wire 10 of the examples and comparative examples. In fig. 3, the horizontal axis represents the wire diameter D of the tungsten wire 10, and the vertical axis represents the number of torsional fracture turns of the tungsten wire 10.

The number of times of torsional fracture of the sample of the example is included in the region 11 surrounded by the solid line and hatched with oblique lines in fig. 3 in the range of the wire diameter of 20 μm or more and 100 μm or less. Specifically, the number of times of torsional breaking of the sample of example was 250 Xexp (-0.026 XD) or more. That is, the curve representing the lower limit value of the torsional breaking revolution number of the sample is represented by 250 Xexp (-0.026 XD) with the line diameter D as a variable. The number of torsional fracture turns of the sample of example was 850 Xexp (-0.026 XD) or less. That is, the curve representing the upper limit value of the torsional breaking revolution number of the sample is represented by 850 × exp (-0.026 × D) with the wire diameter D as a variable. These curves representing the upper limit value and the lower limit value are calculated by fitting based on the measured results of the number of torsional fracture rotations (specifically, the upper limit value and the lower limit value for each wire diameter D).

On the other hand, the number of torsional fracture rotations of the sample according to the comparative example is included in a region 12 surrounded by a dotted line in fig. 3 and shaded with dots. Specifically, the number of torsional fracture turns of the sample of the comparative example was 30 Xexp (-0.026 XD) or more and less than 250 Xexp (-0.026 XD).

As described above, the samples of the examples had a tensile strength of 4800MPa or more at a small wire diameter D of 100 μm or less and a number of torsional fracture turns per 50mm of 250 Xexp (-0.026 XD) or more when applied under a load of a tension T of 50% of the fracture tension of the tungsten wire 10. That is, according to the tungsten wire 10 of the present embodiment, excellent characteristics such as a thin wire, a high tensile strength, and an extremely high breaking strength against torsion can be realized.

When the tungsten content or the rhenium content contained in the tungsten wire 10 is made different, the tensile strength is similarly high in addition to the thinness, and the breaking strength against torsion can be improved.

[ method for producing tungsten wire ]

Next, a method for manufacturing the tungsten wire 10 according to the present embodiment will be described with reference to fig. 4 and 5.

Fig. 4 is a flowchart showing a method for manufacturing the tungsten wire 10 according to the present embodiment. Fig. 5 is a diagram showing the heating temperature in the drawing step included in the method for manufacturing the tungsten wire 10 according to the present embodiment. Fig. 5 shows a case where drawing is performed n times. n is, for example, a natural number of 5 or more.

As shown in fig. 4, first, a tungsten ingot is prepared (S10). Specifically, an aggregate of tungsten powder is prepared, and the prepared aggregate is pressed and sintered (sinter) to produce a tungsten ingot.

In the case of manufacturing the tungsten wire 10 made of a tungsten alloy, a mixture of a tungsten powder and a metal powder (e.g., rhenium powder) at a predetermined ratio is prepared instead of the tungsten powder aggregate. The average particle diameter of the tungsten powder and the rhenium powder is, for example, in the range of 3 μm or more and 4 μm or less, but is not limited thereto. The mixing ratio of the tungsten powder and the rhenium powder depends on the content ratio of tungsten and rhenium in the manufactured tungsten wire 10. The specific gravity of the tungsten ingot thus produced is, for example, 17.4g/cm³Above, but may be 17.8g/cm³Above and 18.2g/cm³The following.

Next, the produced tungsten ingot is swaged (S12). Specifically, a tungsten ingot is forged and compressed from the periphery thereof to be expanded, thereby forming a linear tungsten wire. Alternatively, rolling may be performed instead of swaging.

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

Subsequently, before the hot wire drawing, the tungsten wire was heated at 900 ℃ (S14). Specifically, the tungsten wire is directly heated by a burner or the like. By heating the tungsten wire, an oxide layer is formed on the surface of the tungsten wire so as not to break during the subsequent heating drawing.

Subsequently, hot drawing is performed (S16). Specifically, drawing of a tungsten wire, that is, drawing (thinning) of a tungsten wire was performed while heating the wire using 1 wire drawing die. The heating temperature T1 (see fig. 5) of the first drawing is, for example, 1000 ℃. Further, as the heating temperature is higher, workability of the tungsten wire is improved, and therefore, the wire drawing can be easily performed. The reduction rate of the cross section of a tungsten wire obtained by 1-time drawing using 1 wire drawing die is, for example, 10% or more and 40% or less. In the drawing step, a lubricant in which graphite is dispersed in water may be used.

After the wire drawing step, the surface of the tungsten wire can be smoothed by electrolytic polishing. In the electrolytic polishing, for example, in a state where the tungsten wire and the counter electrode are immersed in an electrolytic solution such as an aqueous sodium hydroxide solution, a potential difference is generated between the tungsten wire and the counter electrode, and electrolytic polishing is performed.

Before obtaining a tungsten wire having a desired wire diameter (no in S18), hot drawing is repeated (S16). The desired wire diameter is a wire diameter at a stage 2 steps before the final drawing step (S26), and is, for example, 170 μm or more and 250 μm or less, but is not limited thereto.

In repeating the hot drawing, a drawing die having a smaller hole diameter than that of the drawing die used for the immediately preceding drawing may be used. When the hot wire drawing is repeated, the heating temperature is lowered as shown in fig. 4 (S20). That is, the tungsten wire is heated at a heating temperature lower than the heating temperature at the time of drawing immediately before. For example, as shown in FIG. 5, the heating temperature T2 in the drawing step of the n-3 th time is lower than the heating temperature in the drawing step of the previous n-4 th time. The heating temperature T2 in the n-3 th drawing step was lower than that in the previous drawing step. Thus, the heating temperature in the drawing step is gradually lowered as the wire diameter becomes smaller.

When the tungsten wire having a desired wire diameter is obtained and the subsequent drawing step is a drawing step 2 steps before the final drawing step (drawing of the n-2 th drawing) (yes in S18), the tungsten wire is heated and drawn while maintaining the temperature (S22). Specifically, as shown in FIG. 5, the heating temperature in the drawing step of the n-2 th time is the same as the heating temperature in the drawing step of the n-3 rd time. The temperature T2 is a temperature higher than the primary recrystallization temperature of tungsten. The temperature T2 is, for example, in the range of 900 ℃ to 1000 ℃.

By raising the temperature during drawing before 2 steps of the final drawing step, primary recrystallization of tungsten contained in the tungsten wire can be promoted. This reduces voids (voids) in the tungsten wire, and facilitates the extension of the crystal grains in the axial direction. This can increase the number of torsional fracture rotations.

Next, before 1 step of the final drawing step, the temperature was lowered to perform hot drawing (S24). As shown in FIG. 5, the heating temperature T3 in the n-1 st drawing step is lower than the heating temperature T2 in the n-2 nd drawing step. The temperature T3 is a temperature lower than the recrystallization temperature of tungsten. For example, the temperature T3 is a temperature of 600 ℃ or higher and 700 ℃ or lower. By drawing the fiber at a relatively low temperature, it contributes to the refinement of crystal grains. At this time, the heating temperature of the mold also needs to be lowered. For example, the heating temperature of the mold is in the range of 300 ℃ to 350 ℃, but is not limited thereto.

The heating temperature in the hot drawing from the 1 st to the n-3 rd times was adjusted according to the amount of the oxide attached to the surface of the tungsten wire. Specifically, the heating temperature is adjusted so that the amount of the oxide is in the range of 0.8 wt% to 1.6 wt% of the tungsten wire, thereby ensuring the wire drawing workability of the n-2 th and n-1 th hot drawing. In the repetition of the hot drawing, the electrolytic polishing may be omitted.

Subsequently, final drawing was performed at normal temperature (S26). That is, the tungsten wire is drawn without heating, thereby further refining the crystal grains. Further, the crystal orientation is aligned in the machine axis direction (specifically, in a direction parallel to the axis P) by the normal temperature drawing. The normal temperature is, for example, a temperature in the range of 0 ℃ to 50 ℃, and 30 ℃ is an example.

In the normal-temperature drawing, a plurality of drawing dies having different bore diameters are used to draw a tungsten wire. In the drawing at room temperature, a liquid lubricant such as water-soluble lubricant is used. Since heating is not performed during drawing at normal temperature, evaporation of the liquid is suppressed. Therefore, the lubricant can sufficiently function as a lubricant.

Compared with the conventional method for processing the tungsten wire, namely heating drawing at the temperature of more than 600 ℃, the method for processing the tungsten wire is processed by cooling with a liquid lubricant without heating the tungsten wire, thereby inhibiting dynamic recovery and dynamic recrystallization, not breaking the wire, contributing to the refinement of crystal grains and obtaining high tensile strength. Further, the crystal grains are made finer and the crystal grains are grown in the axial direction, which contributes to a significant improvement in the torsional strength.

Finally, the tungsten wire having the wire diameter D formed by drawing at room temperature is electropolished (S28). In the electrolytic polishing, for example, in a state where the tungsten wire and the counter electrode are immersed in an electrolytic solution such as an aqueous sodium hydroxide solution, a potential difference is generated between the tungsten wire and the counter electrode, and electrolytic polishing is performed.

Through the above steps, the tungsten wire 10 of the present embodiment is manufactured. Through the above-described manufacturing process, the length of the tungsten wire 10 immediately after manufacturing is, for example, 50km or more, and is industrially applicable. The tungsten wire 10 may be cut into an appropriate length according to the form to be used, and may be used in the form of a needle or a rod. As described above, the tungsten wire 10 of the present embodiment can be industrially mass-produced and used for various tungsten products.

The tungsten wire of the comparative example shown in fig. 2 and 3 is manufactured by so-called hot drawing. For example, in the drawing process of the 1 st time, the heating is performed at a temperature of 1050 ℃ to 1150 ℃. The wire diameter is decreased, and the heating temperature is decreased while the wire drawing is repeated. In the final drawing, the heating is performed at a temperature of 700 ℃ to 800 ℃.

As described above, the heating temperatures in the drawing step were different mainly in the comparative examples and examples. By performing the wire drawing at normal temperature in the final wire drawing step, as described with reference to fig. 2 and 3, the number of times of torsional fracture of the sample of the example can be made higher than that of the comparative example. Further, the number of torsional fracture rotations of the sample of the example can be further increased by making the heating temperature in the drawing step 2 steps before the final drawing step substantially the same as the heating temperature in the drawing step immediately before. In addition, the number of times of torsional fracture of the sample of the example can be further increased by setting the heating temperature of the die to a range of 300 ℃ to 350 ℃ in the drawing step 1 before the final drawing step.

The respective steps shown in the method for manufacturing the tungsten wire 10 may be performed continuously, for example. Specifically, the plurality of wire drawing dies used in steps S16, S22, and S24 are arranged in the production line in the order in which the hole diameters become smaller. Further, a heating device such as a burner is disposed between the wire drawing dies. Further, an electropolishing apparatus may be disposed between the wire drawing dies. On the downstream side (post-process side) of the drawing dies used in steps S16, S22, and S24, the plurality of drawing dies used in step S26 are arranged in the order of decreasing hole diameters, and the electropolishing apparatus is arranged on the downstream side of the drawing die having the smallest hole diameter. Further, each step may be performed individually.

[ tungsten product ]

Next, a specific example of the tungsten product including the tungsten wire 10 of the present embodiment will be described.

< saw line >

As shown in fig. 6, the tungsten wire 10 of the present embodiment can be used as a saw wire 2 of a cutting apparatus 1 for cutting an object such as a silicon ingot or concrete. Fig. 6 is a perspective view showing a cutting device 1 including a saw wire 2 as an example of a tungsten product according to the present embodiment.

As shown in fig. 6, the cutting apparatus 1 is a multi-wire saw including a saw wire 2. The cutting apparatus 1 manufactures a wafer by cutting the ingot 50 into a thin plate shape, for example. The ingot 50 is, for example, a silicon ingot made of single crystal silicon. Specifically, the cutting apparatus 1 cuts the ingot 50 by the plurality of saw wires 2, thereby simultaneously manufacturing a plurality of silicon wafers.

The ingot 50 is not limited to a silicon ingot, and may be another ingot such as silicon carbide or sapphire. Alternatively, the object to be cut by the cutting device 1 may be concrete, glass, or the like.

In the present embodiment, the saw wire 2 includes the tungsten wire 10. Specifically, the saw wire 2 is the tungsten wire 10 itself of the present embodiment. Alternatively, the saw wire 2 may include the tungsten wire 10 and a plurality of abrasive grains attached to the surface of the tungsten wire 10.

As shown in fig. 6, the cutting apparatus 1 further includes 2 guide rollers 3, a support portion 4, and a tension relaxing device 5.

On 2 guide rolls 3, 1 wire 2 is wound several times. For convenience of explanation, the description will be made with 1 circumference of the saw wire 2 as 1 saw wire 2, and a plurality of saw wires 2 are wound around 2 guide rollers 3. That is, in the following description, the plurality of saw lines 2 form 1 continuous saw line 2. The plurality of saw wires 2 may be a plurality of saw wires separated from each other.

The guide rollers 3 rotate the respective saw wires 2 at a predetermined speed by rotating the respective saw wires 2 in a state where the saw wires 2 are stretched straight at a predetermined tension. The plurality of saw wires 2 are arranged in parallel and at equal intervals. Specifically, a plurality of grooves for receiving the wires 2 are provided at predetermined intervals in each of the 2 guide rollers 3. The pitch of the grooves is determined according to the thickness of the wafer to be cut. The width of the groove is substantially the same as the wire diameter of the saw wire 2.

The cutting device 1 may include 3 or more guide rollers 3. A plurality of the saw wires 2 may be wound around 3 or more guide rollers 3.

The support 4 supports an ingot 50 as a cutting object. The support 4 presses the ingot 50 toward the plurality of saw wires 2, so that the ingot 50 is cut by the plurality of saw wires 2.

The tension relaxing device 5 is a device that relaxes the tension applied to the saw wire 2. The tension relaxing device 5 is an elastic body such as a coil spring or a leaf spring, for example. As shown in fig. 6, one end of the tension relaxing device 5, which is, for example, a coil spring, is connected to the guide roller 3, and the other end is fixed to a predetermined wall surface. The tension applied to the saw wire 2 can be relaxed by adjusting the position of the guide roller 3 by the tension relaxing device 5.

Further, although not shown, the cutting device 1 may be a free abrasive type cutting device and may include a supply device for supplying slurry to the saw wire 2. The slurry is a slurry in which abrasive grains are dispersed in a cutting fluid such as a cooling medium. The abrasive grains contained in the slurry adhere to the saw wire 2, whereby the ingot 50 can be easily cut.

The saw wire 2 including the tungsten wire 10 having a high tensile strength can be stretched over the guide roller 3 with a strong tension. This suppresses the vibration of the saw wire 2 when the ingot 50 is cut, and thus the loss of the ingot 50 can be reduced. Further, since the tungsten wire 10 has high breaking strength against twisting, even if the saw wire 2 is twisted during use, it is difficult to break, and the reliability of the cutting device 1 can be improved.

< Strand and rope >

As shown in fig. 7, the tungsten wire 10 of the present embodiment can be used as the stranded wire 20. Fig. 7 is a perspective view showing a part of a stranded wire 20 as an example of a tungsten product of the present embodiment.

As shown in fig. 7, the stranded wire 20 includes a plurality of tungsten wires 10. The stranded wire 20 is manufactured by stranding a plurality of tungsten wires 10 as a wire material.

The stranded wire 20 is, for example, a twisted wire obtained by twisting a plurality of tungsten wires 10. Alternatively, the stranded wire 20 is a clad wire obtained by cladding a plurality of tungsten wires 10. The plurality of wires constituting the stranded wire 20 may not be all the tungsten wire 10. For example, the stranded wire 20 may be formed by twisting a tungsten wire 10 with a carbon steel wire.

Further, as shown in fig. 8, the rope 30 may be manufactured by further twisting the strands 20. Fig. 8 is a perspective view showing a part of a rope 30 as an example of a tungsten product of the present embodiment.

As shown in fig. 8, the rope 30 is manufactured by stranding a plurality of strands 20 as small ropes (strands). By making the twisting direction (e.g., S twist) of the rope 30 different from the twisting direction (e.g., Z twist) of the stranded wire 20, the strength of the rope 30 can be increased.

Since the tungsten wire 10 has high breaking strength against twisting, the stranded wire 20 and the rope 30 produced by stranding the tungsten wire 10 are less likely to break. Therefore, the stranded wire 20 and the rope 30 with high reliability can be realized.

The number of the tungsten wires 10 used for twisting the stranded wire 20 and the rope 30, the number of the stranded wires, and the like are not particularly limited.

< guide pipe >

The tungsten wire 10 of the present embodiment can be used for a medical device member. Fig. 9 is a perspective view showing a part of a duct 40 as an example of a tungsten product of the present embodiment.

Catheter 40 is one example of a medical device component. As shown in fig. 9, the guide tube 40 is a cylindrical elastic member. The wire 41 passes through the interior of the catheter 40. The guide wire 41 is a tungsten wire 10. That is, the tungsten wire 10 of the present embodiment can be used as the guide wire 41 of the catheter 40. Alternatively, the tungsten wire 10 may be used as a wire for reinforcing a catheter.

< Others >

The tungsten wire 10 may be used as a metal mesh such as a screen mesh used for screen printing. For example, a wire mesh screen has a plurality of tungsten wires 10 woven as warp and weft yarns.

The tungsten wire 10 can also be used for a medical needle or a probe for examination, which is an example of a medical device member. The tungsten wire 10 can also be used as a wire for reinforcing an elastic member such as a tire or a conveyor belt. For example, the tire includes a plurality of tungsten wires 10 bundled in a layer as a band or a carcass ply.

[ Effect and the like ]

As described above, the tungsten wire 10 of the present embodiment is a tungsten wire made of tungsten or a tungsten alloy, the wire diameter D of the tungsten wire 10 is 100 μm or less, and the number of times of torsional fracture revolution per 50mm (-0.026 × D) when a tension of 50% of the fracture tension of the tungsten wire 10 is applied as a load is 250 × exp or more.

This makes it possible to realize a sufficiently thin tungsten wire 10 having a higher breaking strength against twisting than before.

For example, the tensile strength of the tungsten wire 10 is 4800MPa or more.

This makes it possible to realize a sufficiently thin tungsten wire 10 that has both high breaking strength and high tensile strength with respect to twisting.

For example, the tungsten content of the tungsten wire 10 is 90 wt% or more.

Thus, even when the tungsten wire 10 is formed of a tungsten alloy, the rhenium content can be made smaller than 10 wt%, for example. Therefore, the workability of the tungsten wire 10 can be improved.

For example, the tungsten product of the present embodiment includes a tungsten wire 10. Further, the tungsten product is, for example, a medical device component such as the saw wire 2, the stranded wire 20, the cord 30, or the catheter 40.

Accordingly, since the tungsten product is manufactured using the sufficiently thin tungsten wire 10 having a higher breaking strength with respect to torsion than in the conventional art, it is possible to suppress the occurrence of breakage or the like in the use of the tungsten product. Therefore, a highly reliable tungsten product can be realized.

(others)

The tungsten wire and the tungsten product of the present invention have been described above based on the above embodiments, but the present invention is not limited to the above embodiments.

For example, the metal contained in the tungsten alloy may not be rhenium. That is, the tungsten alloy may be an alloy of tungsten and 1 or more metals different from tungsten. Examples of the metal different from tungsten include transition metals such as iridium (Ir), ruthenium (Ru), and osmium (Os). The content of the metal other than tungsten is, for example, 0.1 wt% or more and 10 wt% or less, but is not limited thereto. For example, the content of the metal other than tungsten may be less than 0.1 wt% or more than 10 wt%. The same applies to rhenium.

For example, the tensile strength of the tungsten wire 10 may be less than 4800 MPa.

For example, the tungsten wire 10 may be formed of tungsten doped with potassium (K). Doped potassium is present at the grain boundaries of tungsten. The tungsten wire content in the tungsten wire 10 is, for example, 99 wt% or more.

The content of potassium in the tungsten wire 10 is 0.01 wt% or less, but is not limited thereto. For example, the content of potassium in the tungsten wire 10 may be 0.003 wt% or more and 0.010 wt% or less. For example, the content of potassium in the tungsten wire 10 is 0.005 wt%.

The tungsten wire contains a trace amount of potassium, and thus the growth of crystal grains in the radial direction of the tungsten wire can be suppressed. That is, the width of the surface crystal grains can be reduced, and thus the tensile strength can be improved.

The wire diameter, elastic modulus, tensile strength, and torsional breaking rotational number of the tungsten wire (potassium-doped tungsten wire) formed of tungsten doped with potassium are the same as those of the above-described embodiment.

The potassium-doped tungsten wire can be manufactured by the same manufacturing method as in the embodiment, using a potassium-doped tungsten powder instead of the tungsten powder.

For example, the surface of the tungsten wire 10 may be covered with an oxide film, a nitride film, or the like.

In addition, the present invention includes an embodiment obtained by applying various modifications that will occur to those skilled in the art to each embodiment, and an embodiment obtained by arbitrarily combining the components and functions in each embodiment within a scope that does not depart from the gist of the present invention.

Description of the symbols

2 saw wire

10 tungsten wire

20 twisted wire

30 rope

40 catheter (medical equipment parts)