Tungsten alloy wire, its manufacturing method and use

Abstract

The present invention relates to the technical field of tungsten alloy materials, and more particularly to tungsten alloy wire, its manufacturing method, and its use. By mass fraction, the tungsten alloy consists of 0.45-0.9 wt% of L, 0.05-0.2 wt% of oxygen, the remainder being tungsten, and unavoidable impurities, wherein L is one or more of lanthanum, cerium, praseodymium, neodymium, gadolinium, and samarium, the wire diameter is 20-60 μm, and in the wire, L or a compound of L exists linearly along the axial direction of the wire, and the radial average width D of L or the compound of L is ≤5 nm. By linearly doping the element L between the tungsten matrices and controlling the radial average width D of L to ≤5 nm, cracks and breaks caused by second-phase particles during subsequent pressure processing are significantly reduced. This method ensures the mechanical strength of tungsten alloy wires, allowing them to have a tensile strength of 5000 MPa or more for wires with a diameter of 20-60 μm, and is also advantageous for improving the processing performance of tungsten alloy wires.

Description

Technical Field

[0001] The present invention relates to the technical field of tungsten alloy materials, and particularly to tungsten alloy wires, their manufacturing methods, and uses.

Background Art

[0002] Tungsten alloy is an alloy obtained by adding other elements based on tungsten. Among metals, tungsten has the highest melting point, excellent high-temperature strength, creep resistance, thermal conductivity, electrical conductivity, and electron emission characteristics, a large specific gravity, and is widely used in the production of hard alloys and as an additive to alloys. In addition, tungsten alloy is also widely used in fields such as aerospace, medical, automotive, and electronics.

[0003] In order to further improve the processing performance of tungsten alloy materials, currently, rare earth elements such as lanthanum, cerium, praseodymium, and neodymium are doped and dispersed in the tungsten matrix to strengthen the tungsten material. However, rare earth elements function as the second phase in the tungsten matrix and are likely to cause high-temperature sintering, recrystallization during processing, and solid-liquid phase transformation after annealing. Here, these second-phase particles aggregate and grow, and a large number of cracks occur at the interface between the second-phase particles and the tungsten wire. In order to prevent the tungsten wire from breaking due to these cracks during subsequent processing, there is no choice but to limit the wire to a predetermined size, which is disadvantageous for the thinning of tungsten alloy wires.

Summary of the Invention

[0004] In order to solve the problem of the prior art that many cracks and wire breaks occur in tungsten alloy wires due to the introduction of the second phase, the present invention provides a tungsten alloy wire. In terms of mass fraction, the tungsten alloy consists of, as elements, 0.45 - 0.9 wt% of L, 0.05 - 0.2 wt% of oxygen, the balance of tungsten, and inevitable impurities. The aforementioned L is one or more of the following: lanthanum, cerium, praseodymium, neodymium, gadolinium, and samarium. For example, L is lanthanum, or cerium, or praseodymium, or neodymium, or lanthanum and cerium, or lanthanum and praseodymium, or lanthanum and gadolinium, or cerium and neodymium, or praseodymium and gadolinium, or neodymium and samarium, or lanthanum, cerium, and praseodymium, or lanthanum, cerium, and gadolinium, or cerium, praseodymium, neodymium, and gadolinium, etc. Furthermore, for example, the mass fraction of L is 0.45%~0.9%, or 0.5%~0.9%, or 0.7%~0.9%, or 0.45%~0.5%, or 0.45%~0.8%, or 0.45%, 0.5%, 0.55%, 0.6%, 0.7%, 0.8%, 0.85%, etc. The mass fraction of oxygen is typically 0.05-0.2%, 0.05-0.18%, 0.1-0.2%, or 0.14%, 0.15%, 0.1%, 0.13%, 0.16%, 0.2%, etc.

[0005] The diameter of the wire is 20 to 60 μm, for example, 20 μm, 28 μm, 30 μm, 38 μm, 40 μm, 48 μm, 50 μm, 55 μm, 58 μm, 60 μm, etc. The tungsten alloy wire may be uniform, or it may not be perfectly uniform, and there may be differences of a few percent, such as 1%, in some parts.

[0006] In the wire, L or compound L exists linearly along the axial direction of the wire, and the radial average width D of L or compound L is ≤ 5 nm or less. "Linear" means that the dimension of L or compound L in the wire axial direction is much larger than the dimension in the wire radial direction.

[0007] The compound L may be an oxide such as lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, gadolinium oxide, or samarium oxide, but of course, it may also be a compound in other forms.

[0008] Furthermore, in the aforementioned wire, the proportion of tungsten crystal grains with grain boundary angles of ≤15° is ≥50%.

[0009] Furthermore, in the aforementioned wire, the average radial width of the tungsten crystal grains is ≤80 nm.

[0010] Furthermore, if the wire diameter of the wire is >50 μm and ≤60 μm, the radial average width D of L or the compound of L is ≤5 nm, and the tensile strength of the wire is ≥5000 MPa. If the wire diameter of the aforementioned wire is >40 μm and ≤50 μm, then the radial average width D of L or the compound of L is ≤4 nm, and the tensile strength of the wire is ≥5500 MPa. If the wire diameter of the aforementioned wire is >30 μm and ≤40 μm, then the radial average width D of L or the compound of L is ≤3 nm, and the tensile strength of the wire is ≥6000 MPa. When the wire diameter of the aforementioned wire is ≥ 20 μm and ≤ 30 μm, the radial average width D of L or the compound of L is ≤ 2 nm, and the tensile strength of the wire is ≥ 7000 MPa.

[0011] The present invention provides a method for manufacturing the above-mentioned tungsten alloy wire, comprising wet doping, powder production, pressing, sintering, cogging, pressure processing, and electrolytic cleaning.

[0012] Furthermore, the wet doping method involves uniformly dispersing blue tungsten powder in deionized water to obtain a blue tungsten suspension, uniformly dispersing L of nanoscale compound powder in an alkaline solution with pH > 11 to form a second suspension, spraying the second suspension onto the blue tungsten suspension, heating and drying it to obtain doped blue tungsten powder.

[0013] A preferred L nanoscale compound powder is uniformly dispersed in an alkaline solution with pH > 11, and then stirred at high speed using a stirring device with a speed of 1000-2000 r / min. Preferably, the drying method is rapid vacuum heating drying.

[0014] By preparing a suspension of L-element compounds, fine particles are uniformly and directly doped into blue tungsten powder, and these fine particles co-crystallize with the tungsten particles, acting as heterogeneous crystal nuclei. This allows for the production of more uniformly dispersed tungsten alloy powder. This method eliminates the need for elemental acid salt forms, thus broadening the range of selectable dispersed particles that can be produced, and resulting in a more stable and reliable tungsten material.

[0015] Furthermore, the method for producing the blue tungsten powder involves placing ammonium paratungstate in a reduction furnace and reducing it at 400-600°C under the protection of hydrogen and nitrogen gases to obtain the blue tungsten powder. The thickness of the material layer of the ammonium paratungstate powder is <10 mm, the flow rate of hydrogen gas in the reduction furnace is 20-40 L / min, the flow rate of nitrogen gas is 80-160 L / min, the oxygen index of the blue tungsten powder is 2.85 ± 0.05, and the ammonium-tungsten-bronze phase component is >80%.

[0016] Blue tungsten powder is produced using a mixed gas of hydrogen and nitrogen as a reducing protective medium. The properties of the resulting blue tungsten powder are controlled by the thickness of the material layer, the magnitude of the hydrogen gas, and the direction of flow. The oxygen index of the blue tungsten is 2.85 ± 0.05. The blue tungsten is doped with a proportion of ammonium-tungsten-bronze phase exceeding 80%. This blue tungsten has coarse particles and many cracks on its surface, which is advantageous for the penetration of rare earth element solutions, improving the effectiveness of the doping. This, in turn, improves the uniformity of the distribution of the second phase in the tungsten wire, thereby improving the overall mechanical properties and workability of the tungsten wire.

[0017] Furthermore, the powder production method involves reducing the doped blue tungsten powder to obtain alloy powder A with a particle size of 1.5 to 2.6 μm and alloy powder B with a particle size of 3.8 to 4.5 μm, respectively, and then uniformly mixing alloy powder A and alloy powder B to obtain a mixed powder. Preferably, the method for reducing the alloy powder A involves first reducing the doped blue tungsten powder in a hydrogen reduction furnace at 500 to 800°C, and then secondarily reducing it in a hydrogen reduction furnace at 700 to 1000°C to obtain alloy powder A with a particle size of 1.5 to 2.6 μm.

[0018] Preferably, the method for reducing the alloy powder B involves reducing the doped blue tungsten powder in a hydrogen reduction furnace at 700 to 1100°C to obtain alloy powder B with a particle size of 3.8 to 4.5 μm.

[0019] Preferably, the alloy powder A and alloy powder B are uniformly mixed in a mass ratio of 1:(1-2).

[0020] By mixing fine-grained tungsten alloy powder produced by two reduction processes with coarse-grained tungsten alloy powder produced by one high-temperature reduction process in a predetermined ratio, localized doping non-uniformity of the coarse-grained powder during reduction is avoided. This effectively suppresses the occurrence of fine non-uniformity in subsequent alloy powder doping due to aggregation and concentration of the fine-grained powder after reduction, which can lead to defects during subsequent pressure processing, thereby reducing the risk of wire breakage.

[0021] Furthermore, the sintering process specifically involves sintering the pre-sintered material strip obtained by the pressing process at a high temperature of 2200 to 2800°C.

[0022] Furthermore, the pressure processing involves recrystallizing and annealing the alloy rod obtained by cogging, then forging it using a multi-pass continuous rotary forging machine until it becomes a tungsten rod with a diameter of 2.5 to 4.0 mm, and then performing thick wire drawing on the tungsten rod using wire drawing dies of different specifications, repeating the wire drawing pass multiple times with a compression ratio of 35% to 60% to obtain a thick tungsten alloy wire with a diameter of 0.3 to 0.5 mm.

[0023] When tungsten alloy wire is processed at a high compression ratio of 35% to 60%, the fibers of the resulting wire develop more, and the linearization of L element and its compounds is promoted during processing, thereby improving the breaking strength of the wire.

[0024] Furthermore, in the hot working, the alloy bar obtained by cogging is heated to 2000-2600 °C by a medium / high frequency induction coil, recrystallized, and annealed.

[0025] Furthermore, when the tungsten alloy wire is drawn to a diameter of 0.3-0.5 mm, annealing treatment needs to be performed. The annealing temperature is 1300-1700 °C. After annealing, the tungsten alloy wire is cooled in an oxygen environment, and the cumulative processing deformation rate after annealing is ≧95%. The wire drawing is repeated multiple times after annealing to obtain tungsten alloy wires with various diameter specifications. When the tungsten alloy wire is drawn to a diameter of less than 0.3 mm, no annealing treatment is performed.

[0026] After annealing the wire and then cooling it with oxygen, the content and thickness of the oxide layer on the surface of the tungsten alloy wire can be increased, and the lubricating layer of the wire can be effectively improved. Thereby, the wire drawing conditions can be improved, the possibility of wire drawing at a high compression ratio of the wire can be ensured, and the wire breakage probability of the wire can be significantly reduced.

[0027] The annealed and cooled wire is drawn by wire drawing dies of different specifications, and this wire drawing is repeated multiple times to draw the wire to the desired diameter.

[0028] Furthermore, the electrolytic cleaning is first to electrolyze the manufactured tungsten alloy wire with a high-concentration alkali solution and an alternating current, and then to electrolyze it with a low-concentration alkali solution and a direct current.

[0029] Preferably, first, the manufactured tungsten alloy wire is electrolyzed with a potassium hydroxide solution with a concentration of 20 wt% - 30 wt% containing 8-1 groups of alternating current electrolytic sheets, and then electrolyzed in turn with 5-8 groups of potassium hydroxide solutions with a concentration of 5 wt% - 10 wt% containing 5-10 groups of direct current electrolytic sheets, and then the surface is washed with deionized water. The electrolysis speed is 50-200 m / min.

[0030] First, by electrolytically stripping the surface layer of the black tungsten wire with a high-concentration alkaline solution and alternating current, the graphite layer and tungsten oxide layer on the surface can be quickly removed, and grooves on the surface of the wire can be effectively removed. Next, by electrolytically polishing the tungsten wire using a low-concentration alkaline solution and a DC current pulse mode, the uniformity of the diameter of the resulting wire can be further improved, and the wire diameter tolerance can be effectively guaranteed to be within ±1%.

[0031] The present invention further provides the use of the above-mentioned tungsten alloy wire in the fields of cutting, cut protection, cables, screen printing, ropes, or spinning. [Effects of the Invention]

[0032] The tungsten alloy wire according to the present invention has the following advantages compared to the prior art.

[0033] This invention strengthens a tungsten material by using one or more rare earth elements / rare earth compounds as a second phase. By controlling the doping of L or L compounds linearly between the tungsten matrices, and ensuring that the radial average width of L or L compounds is ≤5 nm, cracks and breaks caused by second phase particles during subsequent pressure processing are significantly reduced, ensuring the mechanical strength of the tungsten alloy wire, enabling the wire to have a tensile strength of 5000 MPa or more for wire diameters of 20-60 μm, and is advantageous for improving the processing performance of the tungsten alloy wire.

[0034] To more clearly describe the embodiments of the present invention or the technical solutions in the prior art, the drawings used in describing the embodiments or the prior art will be briefly described below. Clearly, the drawings described below correspond to some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these without requiring any creative effort. [Brief explanation of the drawing]

[0035] [Figure 1]This is a schematic diagram of the method for measuring the radial average width of L or a compound of L according to the present invention. [Modes for carrying out the invention]

[0036] To further clarify the object, technical solution, and advantages of the embodiments of the present invention, the technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments. Note that the embodiments described are only a selection of embodiments of the present invention, not all embodiments. All other embodiments that a person skilled in the art could obtain without creative work based on the embodiments of the present invention are included within the scope of protection of the present invention.

[0037] The present invention provides a tungsten alloy wire, wherein the tungsten alloy consists of, by mass fraction, 0.45-0.9 wt% L, 0.05-0.2 wt% oxygen, the remainder being tungsten, and unavoidable impurities. L is one or more of the following: lanthanum, cerium, praseodymium, neodymium, gadolinium, and samarium.

[0038] It is understandable that unavoidable impurities are other elements that are introduced during the manufacturing process.

[0039] The diameter of the wire is 20 to 60 μm, and in the wire, L or compound L exists linearly along the axial direction of the wire, and the radial average width D of L or compound L is ≤ 5 nm.

[0040] In the aforementioned wire, the proportion of tungsten crystal grains with grain boundary angles of ≤15° is ≥50%. In the aforementioned wire, the average radial width of the tungsten crystal grains is ≤80 nm. If the wire diameter of the aforementioned wire is >50 μm and ≤60 μm, then the radial average width D of L or the compound of L is ≤5 nm, and the tensile strength of the wire is ≥5000 MPa. If the wire diameter of the aforementioned wire is >40 μm and ≤50 μm, then the radial average width D of L or the compound of L is ≤4 nm, and the tensile strength of the wire is ≥5500 MPa. If the wire diameter of the aforementioned wire is >30 μm and ≤40 μm, then the radial average width D of L or the compound of L is ≤3 nm, and the tensile strength of the wire is ≥6000 MPa. When the wire diameter of the aforementioned wire is ≥ 20 μm and ≤ 30 μm, the radial average width D of L or the compound of L is ≤ 2 nm, and the tensile strength of the wire is ≥ 7000 MPa.

[0041] The present invention provides a method for manufacturing tungsten alloy wire, including wet doping, powder production, pressing, sintering, cogging, pressure processing, and electrolytic cleaning.

[0042] The wet doping method involves uniformly dispersing blue tungsten powder in deionized water to obtain a blue tungsten suspension, uniformly dispersing L of nanoscale compound powder in an alkaline solution with pH > 11 to form a second suspension, spraying the second suspension onto the blue tungsten suspension, and then rapidly vacuum-heat-drying it after spraying to obtain doped blue tungsten powder.

[0043] The method for producing the blue tungsten powder involves placing ammonium paratungstate in a reduction furnace and reducing it at 400-600°C under the protection of hydrogen and nitrogen gases to obtain the blue tungsten powder. The thickness of the material layer of the ammonium paratungstate powder is <10 mm, the flow rate of hydrogen gas in the reduction furnace is 20-40 L / min, the flow rate of nitrogen gas is 80-160 L / min, the oxygen index of the blue tungsten powder is 2.85 ± 0.05, and the ammonium-tungsten-bronze phase component is >80%.

[0044] The powder production method involves first reducing the doped blue tungsten powder in a hydrogen reduction furnace at 500-800°C, and then secondarily reducing it in a hydrogen reduction furnace at 700-1000°C to obtain alloy powder A with a particle size of 1.5-2.6 μm.

[0045] The doped blue tungsten powder is reduced in a hydrogen reduction furnace at 700-1100°C to obtain alloy powder B with a particle size of 3.8-4.5 μm.

[0046] Mix alloy powder A and alloy powder B uniformly in a mass ratio of 1:(1-2) to obtain a mixed powder.

[0047] The aforementioned sintering involves sintering the pre-sintered strip obtained by the pressing process at a high temperature of 2200 to 2800°C to achieve a density of 18.6 g / cm³. 3 The objective is to obtain the above sintered elementary strips.

[0048] Preferably, sintering is carried out in a hydrogen gas atmosphere, where the purity of the hydrogen gas is >99.5%.

[0049] The aforementioned pressure processing involves heating the alloy rod obtained by cogging to 2000-2600°C using a medium / high frequency induction coil, recrystallizing and annealing it, and then forging it using a multi-pass continuous rotary forging apparatus until it becomes a tungsten rod with a diameter of 2.5-4.0 mm. The process involves drawing the aforementioned tungsten rod into a thick wire using drawing dies of different specifications, and repeating the drawing pass multiple times with a compression ratio of 35% to 60% to obtain a thick tungsten alloy wire with a diameter of 0.3 to 0.5 mm. The tungsten alloy wire, once drawn to a diameter of 0.3 to 0.5 mm, requires annealing, with an annealing temperature of 1300 to 1700°C. After annealing, the tungsten alloy wire is cooled in an oxygen environment, and the cumulative deformation rate after annealing is ≥ 95%.

[0050] The wire, which has undergone annealing and cooling, is drawn using drawing dies of different specifications, and this drawing process is repeated multiple times to draw the wire to the desired diameter.

[0051] Furthermore, among the steps described above, the pressing and cogging steps preferably employ the following embodiments, but are not limited thereto. That is, Pressing: The mixed powder is pressed into compacts weighing 1.5 to 6 kg each at a pressure of 140 to 240 MPa using an isotropic method. The compacts are then pre-sintered in a hydrogen gas atmosphere at a low temperature of 1200 to 1400°C for 10 to 30 minutes to improve the strength of the compacts. Cogging: Using a cluster rolling mill, continuous rolling is performed at 1600-1700°C to cogging sintered strips with a diameter of 15-25 mm onto alloy rods with a diameter of 8.0-12.0 mm.

[0052] The manufacturing method further includes electrolytic cleaning, namely, first, the manufactured tungsten alloy wire is electrolytically treated with a 20 wt% to 30 wt% potassium hydroxide solution containing 8 to 15 sets of AC electrolytic sheets, then sequentially electrolytically treated with 5 to 8 sets of 5 wt% to 10 wt% potassium hydroxide solutions containing 5 to 10 sets of DC electrolytic sheets, after which the surface is cleaned with deionized water, and the electrolysis rate is 50 to 200 m / min. [Examples]

[0053] Therefore, the present invention provides the tungsten alloy elemental compositions of the following examples and comparative examples, as shown in Table 1.

[0054] [Table 1] Here, "-" indicates that the element in question has not been added.

[0055] Example 1.1 This embodiment provides a tungsten alloy wire manufactured according to the present invention, the elemental composition of the material by mass fraction being 0.6 wt% cerium, 0.137 wt% oxygen, the remainder being tungsten, and unavoidable impurities. The manufacturing steps are as follows: Step 1: Production of blue tungsten: Ammonium paratungstate powder is hydrogen-reduced in a reverse hydrogen continuous reduction furnace at 400°C, 450°C, 500°C, and 560°C, with a material layer thickness of 8 mm, a hydrogen gas flow rate of 30 L / min, and a nitrogen gas flow rate of 140 L / min to obtain blue tungsten powder with an oxygen index of 2.87 and an ammonium-tungsten-bronze phase component of 82%. Step 2: Wet Doping: The blue tungsten powder obtained in Step 1 is uniformly dispersed in deionized water so that the volume ratio of blue tungsten powder to deionized water is 1:15 to obtain a blue tungsten suspension. An appropriate amount of cerium oxide nanopowder is uniformly dispersed in a pH 13 sodium hydroxide solution and stirred at high speed at 1500 r / min using a high-speed emulsifier to form a second suspension. Next, the second suspension is sprayed onto the blue tungsten suspension via a vacuum tube. After spraying is complete, rapid vacuum heating and drying is performed to obtain doped blue tungsten powder. Step 3: Powder Production: The doped blue tungsten powder obtained in Step 2 is subjected to primary reduction in a 3-temperature zone hydrogen reduction furnace at 500°C, 650°C, and 750°C, and then to secondary reduction in a 4-temperature zone hydrogen reduction furnace at 700°C, 810°C, 870°C, and 920°C to obtain alloy powder A with a particle size of 2.0 μm. The doped blue tungsten powder obtained in Step 2 was reduced in a four-temperature zone hydrogen reduction furnace at 720°C, 820°C, 870°C, and 950°C to obtain alloy powder B with a particle size of 4.1 μm. Alloy powder A and alloy powder B are placed in a high-energy mixer in a mass ratio of 1:1.5 and mixed for 120 minutes to obtain a uniform mixed powder with a particle size of 3.0 μm. Step 4: Pressing: The mixed powder obtained in Step 3 is pressed into a compact weighing 3 kg by isotropic means at a pressure of 160 MPa, and the compact is pre-sintered in a hydrogen gas atmosphere and at 1300°C for 20 minutes to obtain a pre-sintered strip. Step 5: Sintering: The pre-sintered strip obtained in Step 4 is sintered at a high temperature of 2600°C to a density of 18.68 g / cm³. 3 Obtaining a sintered element strip, Step 6: Cogging: Using a cluster rolling mill, the sintered strips with a diameter of 20 mm are cogging onto an 8.0 mm alloy rod by continuous rolling at a heating temperature of 1600°C. Step 7: Pressure processing: The alloy rod obtained in Step 6 is heated to 2400°C in a high-frequency induction coil, recrystallized and annealed, and then forged using a multi-pass continuous rotary forging machine until it becomes a tungsten rod with a diameter of 3.0 mm. Step 8: The tungsten rod is subjected to thick wire drawing using drawing dies of different specifications, and the drawing pass is repeated multiple times with a compression ratio of 35% to 60% to obtain a tungsten alloy thick wire material with a diameter of 0.4 mm. Step 9: Annealing: The tungsten alloy thick wire obtained in Step 8 is annealed, and the tungsten alloy wire after annealing is cooled in an oxygen environment, where the annealing temperature is 1650°C and the mass percentage of oxide on the surface of the wire is 1.18%. Step 10: The annealed wire obtained in Step 9 is drawn using drawing dies of different specifications, and the drawing process is repeated multiple times to draw the wire to diameters of 60 μm, 48 μm, 38 μm, 28 μm, and 20 μm, respectively. Step 11: Electrolytic Cleaning: First, the tungsten alloy wire obtained in Step 10 was electrolytically treated with a 22 wt% potassium hydroxide solution containing 12 sets of AC electrolytic sheets. Next, it was electrolytically treated with 6 sets of 6 wt% potassium hydroxide solutions containing 5 sets of DC electrolytic sheets, at an electrolysis rate of 180 m / min. After electrolysis, the surface was washed with deionized water to obtain thin white tungsten wires of different diameters.

[0056] Example 1.2 This embodiment provides a tungsten alloy wire manufactured according to the present invention, the elemental composition of the material by mass fraction being 0.45 wt% lanthanum, 0.078 wt% oxygen, the remainder being tungsten, and unavoidable impurities. In the manufacturing process, all remaining steps were the same as in Example 1.1, except that cerium oxide in step 2 was replaced with lanthanum oxide.

[0057] Example 1.3 This embodiment provides a tungsten alloy wire manufactured according to the present invention, the elemental composition of which, by mass fraction, includes 0.75 wt% neodymium, 0.125 wt% oxygen, the remainder being tungsten, and unavoidable impurities. In the manufacturing process, all remaining steps were the same as in Example 1.1, except that cerium oxide in step 2 was replaced with neodymium oxide.

[0058] Example 1.4 This embodiment provides a tungsten alloy wire manufactured according to the present invention, the elemental composition of the material by mass fraction being 0.35 wt% lanthanum, 0.4 wt% praseodymium, 0.13 wt% oxygen, the remainder being tungsten, and unavoidable impurities. In the manufacturing steps, the remaining steps were the same as in Example 1.1, except that the cerium oxide in Step 2 was replaced with lanthanum oxide and praseodymium oxide.

[0059] Example 1.5 This embodiment provides a tungsten alloy wire manufactured according to the present invention, the elemental composition of the material by mass fraction being 0.35 wt% gadolinium, 0.4 wt% praseodymium, 0.115 wt% oxygen, the remainder being tungsten, and unavoidable impurities. In the manufacturing steps, all remaining steps were the same as in Example 1.1, except that cerium oxide in step 2 was replaced with gadolinium oxide and praseodymium oxide.

[0060] Example 1.6 This embodiment provides a tungsten alloy wire manufactured according to the present invention, the elemental composition of the material by mass fraction being 0.35 wt% samarium, 0.4 wt% gadolinium, 0.172 wt% oxygen, the remainder being tungsten, and unavoidable impurities. In the manufacturing step, all remaining steps were the same as in Example 1.1, except that the cerium oxide in step 2 was replaced with samarium oxide and gadolinium oxide.

[0061] Example 1.7 This embodiment describes the production of a tungsten alloy wire according to the present invention, the elemental composition of the material being the same as in Example 1.1, and the manufacturing steps differ from those of Example 1.1 in the following respects: Step 3: In powder production, alloy powder A and alloy powder B were uniformly mixed in a ratio of 1:4. The remaining manufacturing steps were the same as in Example 1.1.

[0062] Comparative Example 2.1 This embodiment provides a tungsten alloy wire manufactured according to the present invention, the elemental composition of the material by mass fraction being 0.92 wt% cerium, 0.21 wt% oxygen, the remainder being tungsten, and unavoidable impurities. The manufacturing steps were the same as in Example 1.1.

[0063] Comparative Example 2.2 This embodiment provides a tungsten alloy wire manufactured according to the present invention, the elemental composition of the material by mass fraction being 0.4 wt% cerium, 0.52 wt% lanthanum, 0.181 wt% oxygen, the remainder being tungsten, and unavoidable impurities. In the manufacturing steps, all remaining steps were the same as in Example 1.1, except that the second suspension in step 2 further contained lanthanum oxide.

[0064] Comparative Example 2.3 This embodiment provides a tungsten alloy wire manufactured according to the present invention, the elemental composition of which, by mass fraction, contains 0.43 wt% cerium, 0.098 wt% oxygen, the remainder being tungsten, and unavoidable impurities. The manufacturing steps were the same as in Example 1.1.

[0065] Comparative Example 2.4 This embodiment describes the production of a tungsten alloy wire according to the present invention, the elemental composition of the material being the same as in Example 1.1, and the manufacturing steps differ from those of Example 1.1 in the following respects. In step 8, a tungsten rod is subjected to thick wire drawing using drawing dies of different specifications, and the drawing pass is repeated multiple times with a compression ratio of 35% to 60% to obtain a tungsten alloy thick wire with a diameter of 0.2 mm. In step 9, the tungsten alloy thick wire obtained in step 8 is annealed, and the tungsten alloy wire after annealing is cooled in an oxygen environment, where the annealing temperature is 1650°C and the mass percentage of oxide on the surface of the wire is 1.35%. The remaining steps were all the same as in Example 1.1.

[0066] Comparative Example 2.5 This embodiment describes the production of a tungsten alloy wire according to the present invention, the elemental composition of the material being the same as in Example 1.1, and the manufacturing steps differ from those of Example 1.1 in the following respects. In step 8, the tungsten rod was subjected to wire drawing using wire drawing dies of different specifications, and the wire drawing pass was repeated with a compression ratio of 10% to 30% to obtain a thick tungsten alloy wire with a diameter of 0.4 mm. The remaining steps were all the same as in Example 1.1.

[0067] Comparative Example 2.6 This embodiment describes the production of tungsten alloy wire according to the present invention, the elemental composition of the material being the same as in Example 1.1, and the production steps differ from those of Example 1.1 in the following respects. Step 2: Wet doping: The blue tungsten powder obtained in Step 1 is uniformly dispersed in deionized water so that the volume ratio of blue tungsten powder to deionized water is 1:15 to obtain a blue tungsten suspension. An appropriate amount of cerium oxide nanopowder is dissolved in the deionized water and added to the blue tungsten suspension. The mixture is then thoroughly stirred and dried to obtain doped blue tungsten. The stirring speed is 40 r / min and the drying temperature is 160°C. The remaining steps were all the same as in Example 1.1.

[0068] Testing of properties Tensile strength tests were performed on the wires obtained in Examples 1.1 to 1.7 and Comparative Examples 2.1 to 2.3, and the average diameter of the tungsten crystal grains and the radial average width of L or the compound of L were measured. The test results are shown in Table 2. Tensile strength test method: Using a standard tensile testing machine, a 200 mm long tungsten wire was clamped, and a load was applied to one end at a constant speed to obtain data on the breaking force.

[0069] Tensile strength is calculated using the following formula: σ = F / S Here, F is the breaking force (N) and S is the original cross-sectional area (mm).

[0070] Method for measuring the radial average width of tungsten crystal grains: A wire was cut into sheets along the axial direction using a focused ion beam cutting device. These sheets were placed in a scanning electron microscope equipped with an backscatter diffraction (EBSD) device to collect morphology of tungsten crystal grains in the test sample. The width of the upper and lower grain boundaries was measured using conventional measurement software to obtain the radial width of the tungsten crystal grains. The diameters of multiple measured tungsten crystal grains were averaged to obtain the radial average width of the tungsten crystal grains.

[0071] Method for measuring the radial average width of L or L compounds: As shown in Figure 1, a tungsten alloy wire 1 was cut into sheets along the axial direction using a focused ion beam cutting device. The sheets were placed in a high-resolution transmission electron microscope. First, the morphology was observed in light-dark mode. A surface scan was performed at a position where the morphological contrast was clear, and a line scan was performed at a position perpendicular to the axial direction of the tungsten alloy wire to obtain information on elemental distribution and elemental composition. By photographing with a transmission electron microscope at a position where the morphological contrast in the detected sample was clear and there was a clear difference in the elemental distribution (i.e., the position of the aggregated region of each element in the second phase), a high-resolution image of the second phase was obtained. The high-resolution image was then Fourier transformed to obtain a lattice diffraction pattern. Using the obtained diffraction patterns and elemental composition information of the second phase, the corresponding physical phase was identified and compared with a physical phase card to confirm the phase structure of the L or L compound at that location. Then, the width of the L or L compound was measured using software. In Figure 1, 10 represents the tungsten matrix and 20 represents the L or L compound. By measuring the widths of multiple L compounds and calculating the average value, the radial average width of the L or L compound was obtained. For ease of explanation, it should be understood that Figure 1 shows a partial cross-section of the tungsten alloy wire sheet, not the entire sheet.

[0072] [Table 2] JPEG2026528771000004.jpg117152 Here, " / " indicates that the corresponding data does not exist.

[0073] As can be seen from Table 2, the tungsten alloy wire according to the embodiment of the present invention has a tensile strength of 5000 MPa or more for wire diameters of 20 to 60 μm, and the tensile strength increases as the wire diameter decreases, reaching 7000 MPa or more at 28 μm. Furthermore, in the tungsten alloy wire according to the embodiment of the present invention, L or the L compound exists linearly, with a radial average width of less than 5 nm, and the tungsten crystal grains have a radial average width of less than 80 nm.

[0074] As can be seen from the comparison results between Comparative Examples 2.1 to 2.3 and Example 1.1, when the L content in the tungsten alloy wire exceeds 0.9 wt%, the amount of the second phase in the tungsten alloy wire is too large, resulting in insufficient bonding between the crystal grains of the tungsten alloy wire. Furthermore, the increase in the amount of the second phase significantly increases the difficulty of dislocation sliding, making it difficult to process the tungsten alloy wire and impossible to process to a thickness of 60 μm or less. When the L content in the tungsten alloy wire is less than 0.45 wt%, the strengthening effect of the second phase on the tungsten alloy wire is not clear, and the tensile strength decreases.

[0075] As can be seen from the comparison results between Comparative Example 2.6 and Example 1.1, the doping method of this patent results in a smaller average radial width of tungsten crystal grains in the wire, and the size of the second phase particles also becomes more elongated. This is because this patent utilizes nano-sized powder particles dispersed in the tungsten powder during the initial doping process, thereby improving dispersion uniformity. At the same time, after the reduction of the particles, more second phase particles are present inside the tungsten crystal grains, thus improving the grain refinement effect of the tungsten crystal grains. Simultaneously, the finer second phase particles more effectively suppress the deformation of the tungsten crystal grains, thus improving the overall tensile strength of the tungsten wire.

[0076] Tensile strength tests were performed on the wires obtained in Example 1.1 and Comparative Examples 2.4 and 2.5. The proportion of grain boundary angles was measured, and the cumulative processing deformation rate of the wires was calculated. The test results are shown in Table 3.

[0077] Method for measuring the proportion of grain boundary angles: A tungsten alloy wire was cut into sheets along the axial direction using a focused ion beam cutting device. The sheets were placed in a scanning electron microscope equipped with an backscatter diffraction (EBSD) device to collect information on the orientation difference between the tungsten crystal grains of the sheet sample under test and the surrounding tungsten crystal grains. The proportion of grain boundaries with an angle difference of ≤15° or less was then measured.

[0078] Formula for the cumulative processing deformation rate of wire: 1 - D1 * D1 / (D2 * D2) Here, D1 is the diameter of the finished wire, and D2 is the wire diameter during annealing.

[0079] [Table 3] Here, " / " indicates that no corresponding data exists.

[0080] As can be seen from the comparison results between Comparative Example 2.4 and Example 1.1, when annealing treatment is performed on tungsten alloy wire with a wire diameter of less than 0.3 mm, the proportion of grain boundary angles of ≤15° in the tungsten crystal grains in the manufactured product is small. As a result, cracks and breaks caused by second-phase particles increase during subsequent pressure processing, affecting the tensile strength.

[0081] As can be seen from the comparison results between Comparative Example 2.5 and Example 1.1, when a compression ratio of 10-30%, which is the same as that of the conventional wire drawing pass, was used in the pressure processing step, the average width of L in the manufactured wires of each specification was relatively large, and the proportion of grain boundary angles of ≤15° for tungsten crystal grains was small. As a result, cracks and breaks caused by second-phase particles increased during subsequent pressure processing, affecting the tensile strength and making it impossible to process to less than 40 μm. By using a high compression ratio of 35-60% during the processing of tungsten alloy wire, the fibers of the resulting wire develop more, which is advantageous for the fiber formation of L element and its compounds during processing, the deformation of tungsten grain boundaries becomes faster, and the tensile strength of the wire is improved. In addition, by setting the annealing point, increasing the cumulative deformation amount after high-temperature annealing, and improving the degree of wire deformation, the proportion of small-angle tungsten grain boundaries increases, further improving the tensile strength of the tungsten wire.

[0082] The above embodiments are for illustrative purposes only and do not limit the technical solutions of the present invention. The present invention will be described in detail with reference to the above embodiments, but those skilled in the art should understand that it is possible to modify the technical solutions described in the above embodiments or to replace some or all of their technical features with equivalent ones. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. The tungsten alloy wire is composed of, by mass fraction, 0.45 to 0.9 wt% L, 0.05 to 0.2 wt% oxygen, the remainder being tungsten, and unavoidable impurities. The aforementioned L is one or more of the following: lanthanum, cerium, praseodymium, neodymium, gadolinium, and samarium. A tungsten alloy wire characterized in that the wire diameter is 20 to 60 μm, L or compound L exists linearly along the axial direction of the wire, and the average width D along the radial direction of L or compound L is ≤ 5 nm.

2. In the aforementioned wire, the proportion of tungsten crystal grains with a grain boundary angle of ≤15° is ≥50%. Preferably, in the wire, the average width along the radial direction of the tungsten crystal grains is ≤80 nm. Preferably, when the wire diameter of the wire is >50 μm and ≤60 μm, the average width D along the radial direction of L or the compound of L is ≤5 nm, and the tensile strength of the wire is ≥5000 MPa. When the wire diameter of the aforementioned wire is >40 μm and ≤50 μm, the average width D along the radial direction of L or the compound of L is ≤4 nm, and the tensile strength of the wire is ≥5500 MPa. When the wire diameter of the aforementioned wire is >30 μm and ≤40 μm, the average width D along the radial direction of L or the compound of L is ≤3 nm, and the tensile strength of the wire is ≥6000 MPa. The tungsten alloy wire according to claim 1, characterized in that when the wire diameter of the wire is ≥ 20 μm and ≤ 30 μm, the average width D along the radial direction of L or the compound of L is ≤ 2 nm, and the tensile strength of the wire is ≥ 7000 MPa.

3. A method for manufacturing a tungsten alloy wire according to claim 1 or 2, characterized by comprising wet doping, powder production, pressing, sintering, cogging, pressure processing, and electrolytic cleaning.

4. The wet doping method involves uniformly dispersing blue tungsten powder in deionized water to obtain a blue tungsten suspension, uniformly dispersing L of nanoscale compound powder in an alkaline solution with pH > 11 to form a second suspension, spraying the second suspension onto the blue tungsten suspension, heating and drying to obtain doped blue tungsten powder. Preferably, the method for producing the blue tungsten powder is to place ammonium paratungstate in a reduction furnace and reduce it at 400 to 600°C under the protection of hydrogen and nitrogen gases to obtain blue tungsten powder, wherein the thickness of the material layer of the ammonium paratungstate powder is <10 mm, the flow rate of hydrogen gas in the reduction furnace is 20 to 40 L / min, the flow rate of nitrogen gas is 80 to 160 L / min, the oxygen index of the blue tungsten powder is 2.85 ± 0.05, and the ammonium-tungsten-bronze phase component is >80%, as described in claim 3.

5. The aforementioned powder production method involves reducing doped blue tungsten powder to obtain alloy powder A with a particle size of 1.5 to 2.6 μm and alloy powder B with a particle size of 3.8 to 4.5 μm, respectively, and then uniformly mixing alloy powder A and alloy powder B to obtain a mixed powder. Preferably, the method for reducing the alloy powder A involves first reducing the doped blue tungsten powder in a hydrogen reduction furnace at 500 to 800°C, and then secondarily reducing it in the same hydrogen reduction furnace to obtain alloy powder A with a particle size of 1.5 to 2.6 μm. Preferably, the method for reducing the alloy powder B involves reducing the doped blue tungsten powder in a hydrogen reduction furnace at 700 to 1100°C to obtain alloy powder B with a particle size of 3.8 to 4.5 μm. Preferably, the method for producing a tungsten alloy wire according to claim 3, characterized by uniformly mixing the alloy powder A and alloy powder B in a mass ratio of 1:(1-2).

6. The method for manufacturing a tungsten alloy wire according to claim 3, characterized in that the sintering is performed by sintering the pre-sintered material strip obtained by the pressing at a high temperature of 2200 to 2800°C.

7. The aforementioned pressure processing involves recrystallizing and annealing the alloy rod obtained by cogging, then forging it using a multi-pass continuous rotary forging apparatus until it becomes a tungsten rod with a diameter of 2.5 to 4.0 mm, and then performing thick wire drawing on the tungsten rod using wire drawing dies of different specifications, repeating the wire drawing pass multiple times with a compression ratio of 35% to 60% to obtain a thick tungsten alloy wire with a diameter of 0.3 to 0.5 mm. Preferably, in the pressure processing, the alloy rod obtained by cogging is heated to 2000 to 2600°C in a medium / high frequency induction coil, recrystallized, and annealed, as described in claim 3, for the method of producing a tungsten alloy wire.

8. The method for manufacturing a tungsten alloy wire according to claim 3, characterized in that the tungsten alloy wire is drawn to a diameter of 0.3 to 0.5 mm, requires annealing, the annealing temperature is 1300 to 1700°C, the tungsten alloy wire is cooled in an oxygen environment after annealing, the cumulative deformation rate after annealing is ≥ 95%, and the drawing process is repeated multiple times after annealing to obtain tungsten alloy wires of various diameters.

9. The manufacturing method further includes electrolytic cleaning, first electrolyzing the manufactured tungsten alloy wire with a high-concentration alkaline solution and alternating current, and then electrolyzing it with a low-concentration alkaline solution and direct current. Preferably, the method for manufacturing a tungsten alloy wire according to claim 3, characterized in that first, the manufactured tungsten alloy wire is electrolyzed with a potassium hydroxide solution with a concentration of 20 wt% to 30 wt% containing 8 to 15 sets of AC electrolytic sheets, then sequentially electrolyzed with 5 to 8 sets of potassium hydroxide solutions with a concentration of 5 wt% to 10 wt% containing 5 to 10 sets of DC electrolytic sheets, and then the surface is washed with deionized water, and the electrolysis rate is 50 to 200 m / min.

10. Use of tungsten alloy wire according to claim 1 or 2 in the fields of cutting, cut protection, cables, screen printing, ropes, or spinning.

Images