A high-strength ultra-fine tungsten alloy wire and its preparation method

Abstract

The present invention belongs to the technical field of metal materials, and specifically relates to a high-strength ultra-fine tungsten alloy wire and a preparation method thereof. A high-strength ultra-fine tungsten alloy wire, the tungsten alloy wire comprising the following components in weight percentage: 98.5-99.95% tungsten powder, 0.05-1.5% lanthanum hydroxide powder. The present invention provides a high-strength ultra-fine tungsten alloy wire and a preparation method thereof, which obtains a tungsten alloy powder with a uniform distribution of rare earth oxides by efficiently doping a solid (tungsten powder)-solid (lanthanum hydroxide) mixture. The tungsten alloy wire is doped with lanthanum hydroxide instead of lanthanum oxide, because lanthanum oxide easily absorbs water and denatures, resulting in the breakage of the tungsten bar after pressing; then the sintered tungsten alloy billet (20-30 mm) is continuously rolled to 3.0-4.0 mm, and finally, it is drawn to the required specifications by a wire drawing machine, thereby solving the problems of uneven mixing, low strength, high wire breakage rate, low efficiency, and low yield rate of the existing process.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal materials, and in particular relates to a high-strength ultra-fine tungsten alloy wire and a preparation method thereof. Background Art

[0002] High-strength metal wire is primarily used in mechanical wire ropes, cutting wires, and reinforced wires. High-strength metal wires primarily include high-carbon steel wire and tungsten wire. However, existing high-strength metal wire strengths generally fall below 4800 MPa, insufficient for applications such as microwires, diamond cutting, and industrial bend-resistant wire harnesses. As the electronics, medical, and military industries move toward higher density and smaller sizes, high-strength metal wires are required to possess even higher strength and finer diameters, with strength requirements exceeding 6000 MPa and a wire diameter no larger than 0.012 mm. However, existing carbon steel and tungsten wires fail to meet these requirements, creating bottlenecks for their application in these fields.

[0003] By adding rare earth lanthanum oxide to pure tungsten as a strengthening element, the rare earth lanthanum oxide is distributed in the matrix, increasing the strength of the tungsten alloy through dispersion strengthening. Furthermore, the rare earth oxide is distributed at the grain boundaries of the tungsten matrix, effectively preventing grain growth and imparting a fine-grained strengthening effect to the tungsten alloy wire, thereby increasing its strength. However, while strengthening the tungsten alloy with rare earth oxide, the rare earth oxide tends to agglomerate within the matrix due to its dispersed distribution. Traditional processes such as swaging and wire drawing cannot effectively deform the rare earth oxide, leading to wire breakage and unstable performance during the fine wire processing process, resulting in an extremely low yield rate for ultra-fine tungsten alloy wire. Eliminating rare earth oxide agglomeration in the tungsten matrix, increasing the degree of deformation of the rare earth oxide during press working, reducing wire breakage during tungsten alloy wire processing, improving tungsten alloy wire performance, and increasing the yield rate of tungsten alloy wire are urgent issues that need to be addressed in the processing of high-strength ultra-fine tungsten alloy wire.

[0004] The existing tungsten alloy wire and preparation method adopt solid (tungsten powder) - liquid (salt solution) doping method and solid (tungsten powder) - solid (rare earth oxide) mixer doping method for mixing. This method has the following disadvantages: (1) solid (tungsten powder) - liquid (salt solution), ① rare earth salts such as lanthanum nitrate or cerium nitrate are dissolved in pure water, and then sprayed into tungsten powder by liquid spraying. This method has the disadvantages of uneven decomposition of rare earth salts and the inability of rare earth salts to be evenly distributed into the alloy powder on the wall of the doping pot, which leads to the defects of uneven distribution of rare earth oxides and severe agglomeration in the alloy powder after subsequent processing, causing The wire breaks in the subsequent processing; ② The solid-liquid doping method takes 8 to 24 hours, which is a long time and has low production efficiency; ③ Solid-liquid doping requires doping, drying, mixing and other processes, which has many processes, a long process and is difficult to control; (2) Solid (tungsten powder) - solid (rare earth oxide), ① The use of double cone mixers, multi-dimensional mixers and other equipment cannot evenly distribute the rare earth oxide in the tungsten powder, resulting in uneven composition and affecting product strength and processing performance; ② Lanthanum trioxide easily absorbs water and is prone to tungsten bar breakage defects in processes such as isostatic pressing and sintering, which in turn affects subsequent processing.

[0005] Furthermore, in the existing tungsten alloy wire and preparation method, the tungsten alloy wire is processed by rolling + multi-pass swaging or multi-pass swaging process, which has the following disadvantages: (1) the deformation rate is small, and the small deformation rate causes the rare earth oxide to be unable to produce effective deformation, resulting in rare earth oxide enrichment and wire breakage during the fine wire processing process; (2) the multi-pass swaging process is difficult to control, the tungsten alloy wire processing process is difficult to control, and the tungsten alloy wire consistency is poor; (3) each multi-pass swaging process requires heating, and the energy consumption is high.

[0006] The above problems seriously affect the consistency and efficiency of wire blanks and bring many inconveniences to the subsequent processing of the wires. Therefore, it is necessary to provide a high-strength ultra-fine tungsten alloy wire and its corresponding preparation method. Summary of the Invention

[0007] One of the purposes of the present invention is to provide a high-strength ultra-fine tungsten alloy wire to solve the problems of low strength, large wire diameter, unstable performance and low yield in the prior art.

[0008] The technical solution of the high-strength ultra-fine tungsten alloy wire of the present invention is as follows:

[0009] A high-strength ultra-fine tungsten alloy wire comprises the following components in weight percentage: 98.5-99.95% tungsten powder and 0.05-1.5% lanthanum hydroxide powder.

[0010] Preferably, the particle size of the tungsten powder is 1.5-5.0 μm.

[0011] Preferably, the particle size of the lanthanum hydroxide powder is 0.1 to 1.0 μm, and the purity of the lanthanum hydroxide powder is not less than 99.5%.

[0012] A second object of the present invention is to provide a method for preparing high-strength ultra-fine tungsten alloy wire to solve the problems of uneven distribution of rare earth oxides, wire breakage during processing, low production efficiency, difficulty in process control, poor consistency of tungsten alloy wire and high energy consumption in the prior art.

[0013] The technical solution of the method for preparing high-strength ultra-fine tungsten alloy wire of the present invention is as follows:

[0014] A method for preparing high-strength ultra-fine tungsten alloy wire comprises the following steps:

[0015] (1) Preparation of tungsten bars: tungsten powder and lanthanum hydroxide powder are mixed in a mixer, and the mixed tungsten alloy powder is pressed by an isostatic pressing device at a pressing pressure of 180-200 MPa and a holding time of 30-60 seconds to form tungsten alloy billets with a diameter of 16-42 mm. The billets are then sintered in a sintering furnace at a temperature of 2200-2300°C for 20-48 hours to obtain tungsten alloy billets with a diameter of 15-35 mm.

[0016] (2) The first round of rolling: heating the tungsten alloy billet with a diameter of 15-35 mm to 1750-1900 ° C and then keeping it warm, and then performing the first round of rolling. The tungsten alloy billet after the first round of rolling is subjected to the first cleaning and annealing treatment;

[0017] (3) The second round of rolling, heating the tungsten alloy billet after the first cleaning and annealing to 1500-1750 ° C, and then performing the second round of rolling, and performing the second cleaning and annealing treatment on the tungsten alloy billet after the second round of rolling;

[0018] (4) The third round of rolling, heating the tungsten alloy billet after the second cleaning and annealing to 1300-1600°C, and then performing the third round of rolling, and drawing the tungsten alloy billet after the third round of rolling to obtain tungsten alloy wire;

[0019] (5) Preparation of tungsten alloy wire: The drawn tungsten alloy wire is heat treated and then processed by a wire drawing machine to obtain high-strength and ultra-fine tungsten alloy wire.

[0020] Preferably, in step (1), the mixer is a fly cutter + plow cutter combination mixer, wherein the rotation speed of the fly cutter is 2000-4000 rpm, and the rotation speed of the plow cutter is 15-60 rpm; the total mass of the tungsten alloy powder is not less than 500 kg, and the mixing time is 60-150 min.

[0021] Preferably, in step (2), the tungsten alloy billet after being kept warm for 10 to 30 minutes is subjected to a first round of rolling on a Y-type rolling mill to obtain a tungsten alloy billet with a diameter of 8.5 to 9.5 mm, wherein the first round of rolling is 8 to 12 passes, and the first round of rolling discharge speed is 2.5 to 3.5 m / s; the tungsten alloy billet with a diameter of 8.5 to 9.5 mm is subjected to a first cleaning annealing treatment on a medium frequency annealing device, wherein the cleaning medium is a potassium hydroxide or sodium hydroxide solution with a concentration of 15 to 30%, the annealing temperature is 2200 to 2600° C., and the annealing speed is 0.2 to 1.2 m / min.

[0022] Preferably, in step (3), the tungsten alloy billet after the first cleaning and annealing is heated online to 1500-1750° C., and then a second round of rolling is performed on a Y-type rolling mill to obtain a tungsten alloy billet with a diameter of 5.0-6.5 mm, wherein the second round of rolling is 4-8 passes, and the second round of rolling discharge speed is 2.5-3.5 m / s; the alloy tungsten bar with a diameter of 5.0-6.5 mm is subjected to a second cleaning and annealing treatment on a medium frequency annealing device with a cleaning function, wherein the cleaning medium is a potassium hydroxide or sodium hydroxide solution with a concentration of 15-30%, the annealing temperature is 2100-2500° C., and the annealing speed is 0.3-1.5 m / min.

[0023] Preferably, it is characterized in that, in step (4), the tungsten alloy billet after the second cleaning and annealing is heated online to 1300-1600° C., and then a third round of rolling is carried out on a Y-type rolling mill to obtain a tungsten alloy billet with a diameter of 3.0-4.0 mm, wherein the third round of rolling is 4-10 passes, and the third round of rolling discharge speed is 2.5-3.5 m / s; the tungsten alloy billet with a diameter of 3.0-4.0 mm is drawn on a wire drawing machine to a diameter of 0.20-0.50 mm.

[0024] Preferably, in step (5), the drawn tungsten alloy wire is heat-treated at 1200-1600° C., and then processed by a wire drawing machine to a diameter of 0.025-0.035 mm, wherein the heat treatment speed is 10-30 m / min.

[0025] Beneficial effects:

[0026] (1) The purpose of the present invention is to provide a high-strength ultra-fine tungsten alloy wire and a preparation method thereof, wherein uniform tungsten alloy powder is obtained by efficient solid (tungsten powder)-solid (lanthanum hydroxide) doping and mixing. The tungsten alloy wire is doped with lanthanum hydroxide instead of lanthanum oxide, because lanthanum oxide easily absorbs water and denatures, resulting in the breakage of the tungsten bar after pressing; then the sintered tungsten alloy billet (20-30 mm) is continuously rolled to 3.0-4.0 mm, and finally drawn to the required specifications by a wire drawing machine, thereby solving the problems of uneven mixing, high wire breakage rate, low efficiency and low yield rate in the existing process.

[0027] (2) This high-strength, ultra-fine tungsten alloy wire and its preparation method utilize a solid (tungsten powder)-solid (lanthanum hydroxide) efficient doping mixture to ensure the uniformity of the rare earth doping element in the tungsten powder. The pressure processing process utilizes multiple rolling passes combined with pressure processing, which increases the deformation of the rare earth oxide during processing and eliminates the rare earth oxide enrichment phenomenon. It also eliminates the drawback of difficult control of process parameters during rotary forging, improves production efficiency, and reduces energy consumption. This processing method reduces the probability of tungsten alloy wire breakage and improves the production efficiency and yield rate of high-strength, ultra-fine tungsten alloy wire. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further described below in conjunction with specific implementation methods.

[0029] A method for preparing high-strength ultra-fine tungsten alloy wire comprises the following steps:

[0030] (1) Preparation of tungsten bars: 99.95-98.5% tungsten powder and 0.05-1.5% lanthanum hydroxide powder are mixed in a mixer for 60-180 min. The mixed tungsten alloy powder is pressed by isostatic pressing equipment at a pressing pressure of 180-200 MPa and a holding time of 30-90 s to form tungsten alloy billets with a diameter of 16-42 mm. The billets are then sintered in a sintering furnace at a temperature of 2200-2300°C for 20-48 h to obtain tungsten alloy billets with a diameter of 15-35 mm. The particle size of the tungsten powder is 1.5-5.0 μm. m, the particle size of lanthanum hydroxide powder is 0.1-1.0 μm, and the purity of lanthanum hydroxide powder is 99.5-99.999%; the mixer is a fly cutter + plow cutter combination mixer, the speed of the fly cutter responsible for breaking up the tungsten alloy powder is 2000-4000 rpm, and the speed of the plow cutter responsible for the up and down migration of the tungsten alloy powder is 15-60 rpm; the loading amount of tungsten alloy powder (i.e., tungsten powder and lanthanum hydroxide powder) in the mixing process is 500-2000 kg, because if the loading amount of tungsten alloy powder is less than 500 kg, the pressure on the fly cutter will be insufficient, and cavitation will occur during high-speed rotation, resulting in uneven mixing;

[0031] (2) In the first round of rolling, the tungsten alloy billet with a diameter of 15 to 35 mm is heated to 1750 to 1900° C. and then kept warm for 10 to 30 minutes. Then, the billet is rolled on a Y-type rolling mill for the first round to obtain a tungsten alloy billet with a diameter of 8.5 to 9.5 mm. The first round of rolling is 8 to 12 passes, and the first round of rolling discharge speed is 2.5 to 3.5 m / s. The tungsten alloy billet with a diameter of 8.5 to 9.5 mm is subjected to the first cleaning annealing treatment on a medium frequency annealing device, wherein the cleaning medium is a potassium hydroxide or sodium hydroxide solution with a concentration of 15 to 30%; the annealing temperature is 2200 to 2600° C.; and the annealing speed is 0.2 to 1.2 m / min.

[0032] (3) a second round of rolling, wherein the tungsten alloy billet with a diameter of 8.5 to 9.5 mm after the first cleaning and annealing is heated online to 1500 to 1750° C., and then a second round of rolling is performed on a Y-type rolling mill to obtain a tungsten alloy billet with a diameter of 5.0 to 6.5 mm, wherein the second round of rolling is 4 to 8 passes, and the second round of rolling discharge speed is 2.5 to 3.5 m / s; the alloy tungsten bar after the second round of rolling is subjected to a second cleaning and annealing treatment on a medium frequency annealing device with a cleaning function, wherein the cleaning medium is a potassium hydroxide or sodium hydroxide solution with a concentration of 15 to 30%, the annealing temperature is 2100 to 2500° C., and the annealing speed is 0.3 to 1.5 m / min;

[0033] (4) a third round of rolling, wherein the tungsten alloy billet with a diameter of 5.0 to 6.5 mm after the second cleaning and annealing is heated online to 1300 to 1600° C., and then a third round of rolling is performed on a Y-type rolling mill to obtain a tungsten alloy billet with a diameter of 3.0 to 4.0 mm, wherein the third round of rolling is performed 4 to 10 times, and the discharge speed of the third round of rolling is 2.5 to 3.5 m / s; the tungsten alloy billet after the third round of rolling is drawn on a wire drawing machine to a diameter of 0.20 to 0.50 mm;

[0034] (5) Preparation of tungsten alloy wire: The drawn tungsten alloy wire with a diameter of 0.20-0.50 mm is subjected to online heat treatment at a temperature of 1200-1600°C and a speed of 10-30 m / min; the heat-treated tungsten alloy wire is processed by a wire drawing machine to a diameter of 0.025-0.035 mm.

[0035] Example 1

[0036] A method for preparing high-strength ultra-fine tungsten alloy wire comprises the following steps:

[0037] (1) Preparation of tungsten bars: 99.95% tungsten powder and 0.05% lanthanum hydroxide powder were mixed in a mixer for 60 minutes, and then isostatically pressed into tungsten alloy billets with a diameter of 16 mm. The billets were then sintered in a medium-frequency sintering furnace at a temperature of 2200°C for 20 hours to obtain tungsten alloy billets with a diameter of 15 mm. The particle size of the tungsten powder was 1.5 μm, the particle size of the lanthanum hydroxide powder was 0.1 μm, and the purity of the lanthanum hydroxide powder was 99.5%. The mixer was a fly cutter + plow cutter combination mixer, wherein the speed of the fly cutter was 2000 rpm and the speed of the plow cutter was 15 rpm. The loading amount of tungsten alloy powder during the mixing process was 500 kg. If the loading amount of tungsten alloy powder was less than 500 kg, the pressure on the fly cutter would be insufficient, and cavities would appear during high-speed rotation, resulting in uneven mixing.

[0038] (2) In the first round of rolling, the tungsten alloy billet with a diameter of 15 mm was heated to 1750°C and kept warm for 10 minutes. Then, the first round of rolling was carried out on a Y-type rolling mill. After 8 passes, a tungsten alloy billet with a diameter of 8.5 mm was obtained. The discharge speed of the first round of rolling was 2.5 m / s. The tungsten alloy billet with a diameter of 8.5 mm was subjected to the first cleaning annealing treatment on a medium frequency annealing device with a cleaning function. The cleaning medium was a potassium hydroxide solution with a concentration of 15%, the annealing temperature was 2200°C, and the annealing speed was 0.2 m / min.

[0039] (3) The second round of rolling is to heat the tungsten alloy billet with a diameter of 8.5 mm after the first cleaning and annealing to 1500°C online, and then to carry out the second round of rolling on a Y-type rolling mill. After 4 passes, a tungsten alloy billet with a diameter of 5.0 mm is obtained, wherein the discharge speed of the second round of rolling is 2.5 m / s; the alloy tungsten bar after the second round of rolling is subjected to a second cleaning and annealing treatment on a medium frequency annealing device with a cleaning function, wherein the cleaning medium is a potassium hydroxide solution with a concentration of 15%, the annealing temperature is 2100°C, and the annealing speed is 0.3 m / min;

[0040] (4) The third round of rolling, the tungsten alloy billet with a diameter of 5.0 mm after the second cleaning and annealing is heated online to 1300 ° C, and then the third round of rolling is carried out on a Y-type rolling mill. After 4 passes, a tungsten alloy billet with a diameter of 3.0 mm is obtained. The discharge speed of the third round of rolling is 2.5 m / s; the alloy tungsten bar with a diameter of 3.0 mm after the third round of rolling is drawn on a wire drawing machine and processed to a diameter of 0.20 mm;

[0041] (5) Preparation of tungsten alloy wire: The drawn tungsten alloy wire with a diameter of 0.20 mm is subjected to online heat treatment at a heat treatment temperature of 1200°C and a speed of 10 m / min; the heat-treated tungsten alloy wire with a diameter of 0.20 mm is processed by a wire drawing machine to a diameter of 0.025 mm to obtain a high-strength ultra-fine tungsten alloy wire.

[0042] Example 2

[0043] A method for preparing high-strength ultra-fine tungsten alloy wire comprises the following steps:

[0044] (1) Preparation of tungsten bars: 99.3% tungsten powder and 0.7% lanthanum hydroxide powder were mixed in a mixer for 90 min, the mixed tungsten alloy powder was isostatically pressed into a tungsten alloy billet with a diameter of 27 mm, and then sintered in a medium frequency sintering furnace at a temperature of 2250°C for 32 h to obtain a tungsten alloy billet with a diameter of 23 mm; wherein the particle size of the tungsten powder was 2.5 μm, the particle size of the lanthanum hydroxide powder was 0.5 μm, and the purity of the lanthanum hydroxide powder was 99.99%; the mixer was a fly cutter + plow cutter combination mixer, wherein the speed of the fly cutter was 3000 rpm and the speed of the negative plow cutter was 15 rpm; the loading amount of tungsten alloy powder during the mixing process was 1500 kg;

[0045] (2) In the first round of rolling, a tungsten alloy billet with a diameter of 23 mm is heated to 1850°C and kept warm for 15 minutes. Then, the first round of rolling is carried out on a Y-type rolling mill. After 10 passes, the tungsten alloy billet is rolled to a diameter of 9.0 mm. The discharge speed of the first round of rolling is 3.0 m / s. The alloy tungsten bar after the first round of rolling is subjected to the first cleaning annealing treatment on a medium frequency annealing device with a cleaning function. The cleaning medium is a sodium hydroxide solution with a concentration of 20%, the annealing temperature is 2400°C, and the annealing speed is 0.6 m / min.

[0046] (3) The second round of rolling is to heat the tungsten alloy billet with a diameter of 9.0 mm after the first cleaning and annealing to 1650°C online, and then to carry out the second round of rolling on a Y-type rolling mill. After 6 passes, the tungsten alloy billet is rolled to a diameter of 5.8 mm, wherein the discharge speed of the second round of rolling is 2.8 m / s; the alloy tungsten bar after the second round of rolling is subjected to a second cleaning and annealing treatment on a medium frequency annealing device with a cleaning function, wherein the cleaning medium is a sodium hydroxide solution with a concentration of 20%, the annealing temperature is 2300°C, and the annealing speed is 0.9 m / min;

[0047] (4) The third round of rolling, the tungsten alloy billet with a diameter of 5.8 mm after the second cleaning and annealing is heated online to 1500 ° C, and then the third round of rolling is carried out on a Y-type rolling mill. After 6 passes, the tungsten alloy billet is rolled to a diameter of 3.5 mm, wherein the discharge speed of the third round of rolling is 3.0 m / s; the alloy tungsten bar with a diameter of 3.5 mm after the third round of rolling is drawn on a wire drawing machine and processed to a diameter of 0.40 mm;

[0048] (5) Preparation of tungsten alloy wire: The drawn tungsten alloy wire with a diameter of 0.40 mm is subjected to online heat treatment at a heat treatment temperature of 1500°C and a speed of 15 m / min; the heat-treated tungsten alloy wire with a diameter of 0.40 mm is processed by a wire drawing machine to a diameter of 0.030 mm to obtain a high-strength ultra-fine tungsten alloy wire.

[0049] Example 3

[0050] A method for preparing high-strength ultra-fine tungsten alloy wire comprises the following steps:

[0051] (1) Preparation of tungsten bars: 98.5% tungsten powder and 1.5% lanthanum hydroxide powder were mixed in a mixer for 180 min, the mixed tungsten alloy powder was isostatically pressed into a tungsten alloy billet with a diameter of 42 mm, and the isostatically pressed tungsten alloy billet was sintered in a medium frequency sintering furnace at a temperature of 2300°C for 48 h. The diameter of the sintered tungsten alloy billet was 35 mm. The particle size of the tungsten powder was 5.0 μm, the particle size of the lanthanum hydroxide powder was 1.0 μm, and the purity of the lanthanum hydroxide powder was 99.999%. The mixer was a fly cutter + plow cutter combination mixer, the speed of the fly cutter was 4000 rpm, and the speed of the plow cutter was 60 rpm. The loading amount of tungsten alloy powder during the mixing process was 2000 kg.

[0052] (2) In the first round of rolling, the sintered tungsten alloy billet with a diameter of 35 mm was heated to 1900°C and kept warm for 30 minutes. Then, the billet was rolled on a Y-type rolling mill for the first round. After 12 passes, the billet was rolled to a diameter of 9.5 mm. The discharge speed of the first round of rolling was 3.5 m / s. The tungsten alloy billet after the first round of rolling was subjected to the first cleaning annealing treatment on a medium frequency annealing device with a cleaning function. The cleaning medium was a potassium hydroxide solution with a concentration of 30%, the annealing temperature was 2600°C, and the annealing speed was 1.2 m / min.

[0053] (3) The second round of rolling is to heat the tungsten alloy billet with a diameter of 9.5 mm after the first cleaning and annealing to 1750°C online, and then to carry out the second round of rolling on a Y-type rolling mill. After 8 passes, the tungsten alloy billet is rolled to a diameter of 6.5 mm, wherein the second round of rolling discharge speed is 3.5 m / s; the alloy tungsten bar after the second round of rolling is subjected to a second cleaning and annealing treatment on a medium frequency annealing device with a cleaning function, wherein the cleaning medium is a potassium hydroxide solution with a concentration of 30%, the annealing temperature is 2500°C, and the annealing speed is 1.5 m / min;

[0054] (4) The third round of rolling, the tungsten alloy billet with a diameter of 6.5 mm after the second cleaning and annealing is heated online to 1600 ° C, and then the third round of rolling is carried out on a Y-type rolling mill. After 10 passes, the tungsten alloy billet is rolled to a diameter of 4.0 mm, wherein the third round of rolling discharge speed is 3.5 m / s; the alloy tungsten bar with a diameter of 4.0 mm after the third round of rolling is drawn on a wire drawing machine and processed to a diameter of 0.50 mm;

[0055] (5) Preparation of tungsten alloy wire: The drawn tungsten alloy wire with a diameter of 0.50 mm was subjected to online heat treatment at a heat treatment temperature of 1600°C and a speed of 30 m / min; the heat-treated tungsten alloy wire with a diameter of 0.50 mm was processed by a wire drawing machine to a diameter of 0.035 mm to obtain a high-strength ultra-fine tungsten alloy wire.

[0056] Comparative Example 1

[0057] A method for preparing high-strength ultra-fine tungsten alloy wire comprises the following steps:

[0058] (1) Preparation of tungsten bars: 99.95% tungsten powder and 0.05% lanthanum hydroxide powder were mixed in a double cone mixer for 24 hours at a speed of 10 to 16 r / min. The mixed tungsten alloy powder was isostatically pressed into a tungsten alloy billet with a diameter of 16 mm. The isostatically pressed tungsten alloy billet was sintered in a medium frequency sintering furnace at a temperature of 2200°C for 20 hours. The diameter of the sintered tungsten alloy billet was 15 mm. The particle size of the tungsten powder was 1.5 μm, the particle size of the lanthanum hydroxide powder was 0.1 μm, and the purity of the lanthanum hydroxide powder was 99.5%.

[0059] (2) In the first round of rolling, the sintered tungsten alloy billet with a diameter of 15 mm is heated to 1750°C and kept warm for 10 minutes. The billet is then rolled on a Y-type rolling mill for the first round. After 8 passes, the billet is rolled to a diameter of 8.5 mm. The discharge speed of the first round of rolling is 2.5 m / s. The tungsten alloy billet after the first round of rolling is subjected to the first cleaning annealing treatment on a medium frequency annealing device with a cleaning function. The cleaning medium is a potassium hydroxide solution with a concentration of 15%, the annealing temperature is 2200°C, and the annealing speed is 0.2 m / min.

[0060] (3) First rotary forging, the tungsten alloy billet with a diameter of 8.55 mm after the first cleaning and annealing is processed by rotary forging to a diameter of 5.0 mm; the tungsten alloy billet after rotary forging is subjected to a second cleaning and annealing treatment on a medium frequency annealing device with a cleaning function, wherein the cleaning medium is a potassium hydroxide solution with a concentration of 15%, the annealing temperature is 2100°C, and the annealing speed is 0.3 m / min;

[0061] (4) a second rotary forging process, wherein the tungsten alloy billet with a diameter of 5.0 mm after the second cleaning and annealing is processed into a diameter of 3.0 mm by rotary forging; and the tungsten alloy billet with a diameter of 3.0 mm is then drawn on a wire drawing machine to a diameter of 0.20 mm;

[0062] (5) Preparation of tungsten alloy wire: The tungsten alloy wire with a diameter of 0.20 mm was subjected to online heat treatment at a heat treatment temperature of 1200°C and a speed of 10 m / min; the tungsten alloy wire with a diameter of 0.20 mm after heat treatment was processed by a wire drawing machine to 0.025 mm to obtain high-strength ultra-fine tungsten alloy wire.

[0063] Comparative Example 2

[0064] A method for preparing high-strength ultra-fine tungsten alloy wire comprises the following steps:

[0065] (1) Preparation of tungsten bars: 99.3% by mass of tungsten powder and 0.7% by mass of lanthanum hydroxide powder were mixed in a three-dimensional mixer for 24 hours. The mixed tungsten alloy powder was isostatically pressed into a tungsten alloy billet with a diameter of 27 mm. The isostatically pressed tungsten alloy billet was sintered in a medium frequency sintering furnace at a temperature of 2250°C for 32 hours. The diameter of the sintered tungsten alloy billet was 23 mm. The particle size of the tungsten powder was 2.5 μm, the particle size of the lanthanum hydroxide powder was 0.5 μm, and the purity of the lanthanum hydroxide powder was 99.99%.

[0066] (2) In the first round of rolling, a tungsten alloy billet with a diameter of 23 mm is heated to 1850°C and kept warm for 15 minutes. The billet is then rolled on a Y-type rolling mill for the first round. After 10 passes, the billet is rolled to a diameter of 9.0 mm. The discharge speed of the first round of rolling is 3.0 m / s. The tungsten alloy billet after the first round of rolling is subjected to the first cleaning annealing treatment on a medium frequency annealing device with a cleaning function. The cleaning medium is a potassium hydroxide or sodium hydroxide solution with a concentration of 20%, the annealing temperature is 2400°C, and the annealing speed is 0.6 m / min.

[0067] (3) a first rotary forging process, wherein the tungsten alloy billet having a diameter of 9.0 mm after the first cleaning and annealing in step (2) is processed by rotary forging to a diameter of 5.8 mm; the tungsten alloy billet after rotary forging is subjected to a second cleaning and annealing process on a medium frequency annealing device with a cleaning function, wherein the cleaning medium is a potassium hydroxide solution with a concentration of 20%, the annealing temperature is 2300° C., and the annealing speed is 0.9 m / min;

[0068] (4) a second rotary forging process, wherein the tungsten alloy billet having a diameter of 5.8 mm after the second cleaning and annealing in step (3) is rotary forged to a diameter of 3.5 mm, and then drawn on a wire drawing machine to a diameter of 0.40 mm;

[0069] (5) Preparation of tungsten alloy wire: The tungsten alloy wire with a diameter of 0.40 mm after being drawn in step (4) is subjected to online heat treatment at a heat treatment temperature of 1500° C. and a speed of 15 m / min; the tungsten alloy wire with a diameter of 0.40 mm after heat treatment is processed by a wire drawing machine to a diameter of 0.030 mm to obtain a high-strength ultra-fine tungsten alloy wire.

[0070] Detection method

[0071] The lanthanum trioxide content in the tungsten alloys prepared in the above examples and comparative examples was determined according to YS / T1289-2018 "Determination of lanthanum trioxide content in tungsten-lanthanum alloys - Na2EDTA titration method." The strength of the tungsten alloy wires prepared in the above examples and comparative examples was tested according to GB / T 10573-2020 "Non-ferrous metal filament tensile test method." The yield rate was tested based on the rule that qualified products should be products with a length greater than 100 km. The test results are shown in Table 1 below:

[0072] Table 1 Tungsten alloy wire performance test results

[0073]

[0074] This high-strength, ultra-fine tungsten alloy wire and its preparation method utilize a highly efficient solid (tungsten powder)-solid (lanthanum hydroxide) doping mixture to ensure uniformity of the rare earth doping element within the tungsten powder. The press-forming process utilizes multiple rolling passes combined with press-forming, which increases the deformation of the rare earth oxides during processing and eliminates rare earth oxide enrichment. This eliminates the difficulty in controlling process parameters during rotary swaging, improves production efficiency, and reduces energy consumption. This processing method reduces the likelihood of wire breakage, thereby increasing both the production efficiency and yield rate of high-strength, ultra-fine tungsten alloy wire.

[0075] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A high-strength ultra-fine tungsten alloy wire, characterized in that: The tungsten alloy wire comprises the following components in weight percentage: 98.5-99.95% tungsten powder and 0.05-1.5% lanthanum hydroxide powder, wherein the particle size of the tungsten powder is 1.5-5.0 μm, the particle size of the lanthanum hydroxide powder is 0.1-1.0 μm, and the purity of the lanthanum hydroxide powder is not less than 99.5%; The method for preparing the high-strength ultra-fine tungsten alloy wire comprises the following steps: (1) Preparation of tungsten bars: tungsten powder and lanthanum hydroxide powder are mixed in a mixer, and the mixed tungsten alloy powder is pressed by an isostatic pressing device at a pressing pressure of 180-200 MPa and a holding time of 30-60 seconds to form tungsten alloy billets with a diameter of 16-42 mm. The billets are then sintered in a sintering furnace at a temperature of 2200-2300°C for 20-48 hours to obtain tungsten alloy billets with a diameter of 15-35 mm. The mixer is a fly cutter + plow cutter combination mixer. (2) In the first round of rolling, the tungsten alloy billet with a diameter of 15 to 35 mm is heated to 1750 to 1900°C and then kept warm. After being kept warm for 10 to 30 minutes, the tungsten alloy billet is rolled on a Y-type rolling mill for the first round to obtain a tungsten alloy billet with a diameter of 8.5 to 9.5 mm. The tungsten alloy billet after the first round of rolling is subjected to the first cleaning and annealing treatment; (3) The second round of rolling, heating the tungsten alloy billet after the first cleaning and annealing to 1500-1750°C, and then performing the second round of rolling to obtain a tungsten alloy billet with a diameter of 5.0-6.5 mm, and performing the second cleaning and annealing treatment on the tungsten alloy billet after the second round of rolling; (4) The third round of rolling, heating the tungsten alloy billet after the second cleaning and annealing to 1300-1600°C, and then performing the third round of rolling to obtain a tungsten alloy billet with a diameter of 3.0-4.0 mm. The tungsten alloy billet after the third round of rolling is drawn to obtain a tungsten alloy wire with a diameter of 0.20-0.50 mm; (5) Preparation of tungsten alloy wire: The drawn tungsten alloy wire is heat treated and then processed by a wire drawing machine to obtain high-strength and ultra-fine tungsten alloy wire with a diameter of 0.025-0.035 mm.

2. A method for preparing high-strength ultra-fine tungsten alloy wire according to claim 1, characterized in that: The steps include: (1) Preparation of tungsten bars: tungsten powder and lanthanum hydroxide powder are mixed in a mixer, and the mixed tungsten alloy powder is pressed by an isostatic pressing device at a pressing pressure of 180-200 MPa and a holding time of 30-60 seconds to form tungsten alloy billets with a diameter of 16-42 mm. The billets are then sintered in a sintering furnace at a temperature of 2200-2300°C for 20-48 hours to obtain tungsten alloy billets with a diameter of 15-35 mm. The mixer is a fly cutter + plow cutter combination mixer. (2) In the first round of rolling, the tungsten alloy billet with a diameter of 15 to 35 mm is heated to 1750 to 1900°C and then kept warm. The tungsten alloy billet after being kept warm for 10 to 30 minutes is rolled in the first round on a Y-type rolling mill to obtain a tungsten alloy billet with a diameter of 8.5 to 9.5 mm. The first round of rolling is 8 to 12 passes, and the first round of rolling discharge speed is 2.5 to 3.5 m / s. The tungsten alloy billet with a diameter of 8.5 to 9.5 mm is subjected to the first cleaning and annealing treatment on a medium frequency annealing device. The cleaning medium is a potassium hydroxide or sodium hydroxide solution with a concentration of 15 to 30%, the annealing temperature is 2200 to 2600°C, and the annealing speed is 0.2 to 1.2 m / min. (3) The second round of rolling, heating the tungsten alloy billet after the first cleaning and annealing to 1500-1750°C, and then performing the second round of rolling to obtain a tungsten alloy billet with a diameter of 5.0-6.5 mm, and performing the second cleaning and annealing treatment on the tungsten alloy billet after the second round of rolling; (4) The third round of rolling, heating the tungsten alloy billet after the second cleaning and annealing to 1300-1600°C, and then performing the third round of rolling to obtain a tungsten alloy billet with a diameter of 3.0-4.0 mm. The tungsten alloy billet after the third round of rolling is drawn to obtain a tungsten alloy wire with a diameter of 0.20-0.50 mm; (5) Preparation of tungsten alloy wire: The drawn tungsten alloy wire is heat treated and then processed by a wire drawing machine to obtain high-strength and ultra-fine tungsten alloy wire with a diameter of 0.025-0.035 mm.

3. The method for preparing high-strength ultra-fine tungsten alloy wire according to claim 2, wherein: In step (1), the mixer is a fly cutter + plow cutter combination mixer, wherein the rotation speed of the fly cutter is 2000-4000 rpm, and the rotation speed of the plow cutter is 15-60 rpm; the total mass of the tungsten alloy powder is not less than 500 kg, and the mixing time is 60-150 min.

4. The method for preparing high-strength ultra-fine tungsten alloy wire according to claim 2, wherein: In step (3), the tungsten alloy billet after the first cleaning and annealing is heated online to 1500-1750°C, and then a second round of rolling is carried out on a Y-type rolling mill, wherein the second round of rolling is 4-8 passes, and the second round of rolling discharge speed is 2.5-3.5 m / s; the alloy tungsten bar with a diameter of 5.0-6.5 mm is subjected to a second cleaning and annealing treatment on a medium frequency annealing device with a cleaning function, wherein the cleaning medium is a potassium hydroxide or sodium hydroxide solution with a concentration of 15-30%, the annealing temperature is 2100-2500°C, and the annealing speed is 0.3-1.5 m / min.

5. The method for preparing high-strength ultra-fine tungsten alloy wire according to claim 2, wherein: In step (4), the tungsten alloy billet after the second cleaning and annealing is heated online to 1300-1600°C, and then subjected to a third round of rolling on a Y-type rolling mill, wherein the third round of rolling is 4-10 passes and the third round of rolling discharge speed is 2.5-3.5 m / s; the tungsten alloy billet with a diameter of 3.0-4.0 mm is drawn on a wire drawing machine to a diameter of 0.20-0.50 mm.

6. The method for preparing high-strength ultra-fine tungsten alloy wire according to claim 2, wherein: In step (5), the drawn tungsten alloy wire is heat-treated at 1200-1600°C, and then processed by a wire drawing machine to a diameter of 0.025-0.035 mm, wherein the heat treatment speed is 10-30 m / min.

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