Potassium-doped tungsten rod for highly flexible tungsten wire rope and manufacturing method thereof

Abstract

The present invention discloses a potassium-doped tungsten rod for high-flexibility tungsten wire ropes and its manufacturing method, belonging to the technical field of powders for metal additive manufacturing, which includes the following steps: (1) material selection - (2) pre-reduction - (3) vacuum spray doping - (4) reduction - (5) batch pickling - (6) mixing - (7) hard film cold isostatic pressing - (8) low-temperature impurity removal - (9) vertical melting pre-sintering - (10) intermediate-frequency sintering, finally obtaining a potassium-doped tungsten rod. Compared with the prior art, the present invention uses specially made potassium-doped tungsten powder with high activity and narrow particle size range to produce tungsten rods. Through the regulation of the narrow particle size range, during the sintering of the combination of vertical melting and intermediate frequency, the potassium-doped tungsten billet obtains stable and micro-nano-level initial crystallization; and after being processed into tungsten wire, the finished product rate reaches 88% - 90%, the qualified rate ≥ 95%, the tensile strength ≥ 2250 N / mm<supgt;2< / supgt;, the high-temperature recrystallization temperature is 1850 °C - 2380 °C, the high-temperature sag value of the 0.39 mm specification ≤ 1.5 mm, the aspect ratio ≥ 15, and the service life is extended.

Description

Technical Field

[0001] The present invention relates to the technical field of powders for metal additive manufacturing, and particularly relates to a potassium-doped tungsten rod for a highly flexible tungsten wire rope and a manufacturing method thereof. Background Art

[0002] The tungsten wire rope is one of the important components in the single crystal furnace equipment in the photovoltaic industry and is used for stretching polysilicon in the crystal growth furnace. As the photovoltaic silicon wafers develop towards larger sizes, the outer diameter of the current M12 silicon wafers has reached up to 295 mm, and the weight of polysilicon per furnace increases by more than 19%. Therefore, higher performance requirements are put forward for the tungsten wire rope, which are mainly manifested as follows: the number of strands wound by the tungsten wire rope increases, from the 19*7 structure of 133 strands to the 4*19*7 structure of 532 strands, and it is still increasing. By increasing the number of strands, the load-bearing limit and tensile resistance of the tungsten wire rope in the hot and cold states in the crystal growth furnace are improved; since the polysilicon needs to be heated to about 1500 °C to form a single crystal, the tungsten wire rope needs to withstand the tensile force in the crystal direction for a long time at a temperature exceeding 1000 °C without breaking. It must have a relatively high complete recrystallization temperature, a low anti-down vertical value, and excellent high-temperature creep resistance. Based on the above performance requirements, improving the tungsten rod used for producing the tungsten wire rope is one of the very fast and effective methods. However, the tungsten wire rope produced by the traditional pure tungsten rod has disadvantages such as poor toughness, low recrystallization temperature, low strength, poor high-temperature anti-sagging performance and creep resistance, and short service life; the doped tungsten rod doped with rare earth elements, although to a certain extent solves the problems of low strength, poor toughness, and low recrystallization temperature of the tungsten wire rope made of pure tungsten, but since the melting points of rare earth oxides are all greater than 2400 °C, and they are all solid-state extrusion and stretching during the reprocessing. On the one hand, the growth rate of internal stress during the processing is several times that of the pure tungsten rod. On the other hand, the displacement of rare earth oxides is likely to cause the fracture of fibrosis in the tissue, and the yield rate of the finished wire rod with a specification of less than 1.0 mm is greatly reduced, and there are also problems such as high tungsten wire break points and poor toughness stability, and it cannot fully and effectively meet the requirements for performance improvement of the tungsten wire rope. The traditional potassium-doped tungsten rod is developed for the use of lamp filaments. The density of the tungsten rod generally remains at about 91% of the theoretical density, and the crystallization of the tungsten rod is relatively coarse. It still cannot meet the requirements for performance improvement of the tungsten wire rope in terms of high-temperature creep resistance, strength, toughness, recrystallization temperature, etc. in the core area of the tungsten wire for the 0.6-1.2 mm tungsten wire rope.

[0003] In the prior art, Chinese invention patent CN110526295A discloses a preparation method of ytterbium-doped potassium gadolinium tungstate nanocrystal particles. Micron-sized ytterbium-doped potassium gadolinium tungstate particles are wet ball-milled and then subjected to a first separation treatment to obtain first ytterbium-doped potassium gadolinium tungstate nanoparticles. The first ytterbium-doped potassium gadolinium tungstate nanoparticles are etched with an acid solution and then subjected to a second separation treatment, and then washed to obtain second ytterbium-doped potassium gadolinium tungstate nanoparticles. The first ytterbium-doped potassium gadolinium tungstate nanoparticles exist in agglomeration in water, and the second ytterbium-doped potassium gadolinium tungstate nanoparticles exist in dispersion in water. The preparation method is simple and easy to operate, does not cause environmental pollution, and can control the size of the nanoparticles after ball-milling, and is suitable for large-scale preparation of monodisperse ytterbium-doped potassium gadolinium tungstate nanoparticles; moreover, the prepared ytterbium-doped potassium gadolinium tungstate nanocrystal particles are stably dispersed in water. However, the high-temperature creep resistance, strength, toughness, and recrystallization temperature of the ytterbium-doped potassium gadolinium tungstate nanocrystal particles obtained by this invention still need to be improved. Summary of the Invention

[0004] In the prior art, the high density and crystallization of potassium-doped tungsten rods are a set of mutually restrictive product parameters. In the conventional production process, when the density of potassium-doped tungsten rods is increased, their crystallization will coarsen. In view of the deficiencies of the prior art, how to provide a preparation method of tungsten rods for making highly flexible tungsten wires to balance the relationship between the two in order to obtain potassium-doped tungsten rods with high density and micron-sized crystals is the basic purpose of the present invention. Making the tungsten wires made of such tungsten rods have high-temperature creep resistance, high strength, a relatively high recrystallization temperature, and stable toughness, and effectively improving processing problems such as low finished product rate and low yield of tungsten wires is a further purpose. In addition, further enabling the tungsten wires to obtain better high-temperature strength, high-temperature sag resistance, and anti-deformation performance, and reducing the processing cost of rod and wire materials, energy conservation and consumption reduction are another purpose.

[0005] In order to achieve the above-mentioned invention purposes, the present invention adopts the following technical solutions:

[0006] A manufacturing method of potassium-doped tungsten rods for highly flexible tungsten wires is as follows:

[0007] (1) Material selection

[0008] Metatungstate ammonium monohydrate is mixed with spherical ammonium paratungstate, and the obtained mixture is used as the raw material;

[0009] (2) Pre-reduction

[0010] The raw material in step (1) is pre-reduced by a reduction furnace with at least four temperature zones to obtain ammonium tungsten bronze with cracks on the surface;

[0011] The raw material in step (1) is reduced by a four-zone temperature reduction furnace to obtain ammonium tungsten bronze with cracks on the surface;

[0012] (3) Vacuum spray doping

[0013] It is divided into the following four stages:

[0014] In the first stage, an appropriate amount of ammonium tungsten bronze obtained in step (2) is placed in a vacuum doping pot, and the vacuum is pumped to ≤500 pa;

[0015] In the second stage, potassium hydroxide, silicic acid, and aluminum nitrate solids are respectively put into water at 50 - 70 °C and completely dissolved, then dilute nitric acid is added, and the above solution is continuously stirred to prepare a doping agent solution. The temperature of the doping agent solution is heated to 40 - 50 °C, and then it is slowly sprayed into the vacuum doping pot from the atomizing holes. The total amount does not exceed 1 / 3 of the rated addition amount. The steam input valve is opened 1 / 3, and the steam pressure is controlled at 0.1 - 0.2 Mpa. At this time, the materials in the pot must be kept turning, and the pot body is heated with steam to keep the temperature of the materials in the furnace at 55 - 85 °C;

[0016] In the third stage, the turning frequency of the pot body is increased, and the remaining doping agent solution is atomized and sprayed in within 30 - 50 minutes. The temperature in the furnace is kept at 85 - 95 °C, the steam input valve is opened 2 / 3, and the steam pressure is controlled at 0.1 - 0.2 Mpa;

[0017] In the fourth stage, after all the doping agent atomization spraying is completed, the steam input valve is fully opened, the steam pressure is controlled at 0.2 - 0.3 Mpa, the temperature in the furnace is raised to 100 - 120 °C, and it is continuously dried for 3.5 hours to completely evaporate the water. When the vacuum degree in the vacuum doping pot remains at 400 - 500 Mpa, the steam heating is turned off, and water cooling is carried out until the temperature in the furnace drops to 50 - 55 °C. The discharge valve is opened and sieved through a 20 - 100 - mesh sieve to obtain potassium - doped ammonium tungsten bronze;

[0018] (4) Reduction

[0019] The potassium - doped ammonium tungsten bronze obtained in step (3) is reduced once in a hydrogen atmosphere to obtain potassium - doped tungsten powder with an average particle size of 3.0 μm - 3.2 μm;

[0020] In the as - produced particle size distribution of the potassium - doped tungsten powder, the particle size D10 is 3.1 μm - 3.6 μm, the particle size D50 is 8.0 μm - 15 μm, and the particle size D90 is 25 μm - 32 μm;

[0021] In the ground particle size distribution of the potassium - doped tungsten powder, the particle size D10 is 1.5 μm - 2.1 μm, the particle size D50 is 3.4 μm - 4.1 μm, and the particle size D90 is 6.5 μm - 8.2 μm;

[0022] (5) Batch grouping and pickling

[0023] The potassium-doped tungsten powder obtained in step (4) is successively washed with 4 mol / L dilute hydrochloric acid and 2 mL / L dilute hydrofluoric acid to remove the ineffective potassium and other impurities in the potassium-doped tungsten powder. Subsequently, water at a temperature of 50°C to 65°C is used to remove the residual dilute hydrochloric acid and dilute hydrofluoric acid. Finally, the tungsten mud is dried in a vacuum box, and the dried tungsten mud is re-crushed and sieved through a sieve to obtain pickled potassium-doped tungsten powder;

[0024] (6) Mixing

[0025] The pickled potassium-doped tungsten powder obtained in step (5) is put into a high-speed mixer and mixed for 60 to 120 minutes under the protection of nitrogen. When it is cooled to 40°C to 50°C, it is unloaded and sieved through a 150- to 200-mesh sieve to obtain potassium-doped compound powder;

[0026] (7) Hard film cold isostatic pressing

[0027] The potassium-doped compound powder obtained in step (6) is loaded into a rubber hard mold sleeve with a single weight of 3000 g / root to 4000 g / root, with a length of 800 mm, a diameter of 25.5 mm to 27 mm, and a wall thickness of 1.8 mm to 2.2 mm, vibrated and compacted, sealed and fastened, placed in a cold isostatic press, and a potassium-doped tungsten green body with good appearance and certain strength is obtained under a pressing pressure of 140 Mpa to 170 Mpa;

[0028] (8) Low-temperature impurity removal

[0029] The potassium-doped tungsten green body obtained in step (7) is placed in a hydrogen protection furnace at 1000°C to 1100°C and fired for 40 minutes to 60 minutes to obtain a potassium-doped tungsten blank with improved strength;

[0030] (9) Plumbicon pre-sintering

[0031] The potassium-doped tungsten blank obtained in step (8) is placed in a plumbicon furnace and sintered by energization under hydrogen protection to volatilize more than 95% of the impurities, reaching a density of 15.5 g / cm 3 ~16.5 g / cm 3 , and the initial crystal size obtained on the cross section is 1.5 nm to 5 nm;

[0032] The energized sintering system is in sequence of heating up, heating up, heat preservation, heat preservation;

[0033] The current / time parameters are in sequence of: heating up 0 A to 2800 A / 5 min, heating up 2800 A to 3850 A / 6 min, heating up 3850 A to 4820 A / 6 min, heat preservation 4820 A / 21 min; the hydrogen flow rate is 1.8 m 3 / h to 2.2 m 3 / h;

[0034] (10) Medium-frequency sintering

[0035] Place the incompletely dense potassium-doped tungsten bars obtained in step (9) in an intermediate frequency furnace, and place the tungsten bars vertically in a stacked firing manner. Sinter them under hydrogen protection using a double hydrogen inlet method at the furnace bottom and furnace top, and use an infrared temperature measurement + PLC temperature control system to automatically control the sintering process. The sintering regime is in sequence: heating, holding, heating, holding, heating, holding, heating, holding, heating, holding, heating, holding; the temperature / time parameters are in sequence: (0 - 1250 °C) / 430 min, holding: 1250 °C / 90 min, heating (1250 - 1500 °C) / 150 min, holding 1500 °C / 120 min, heating (1500 - 1800 °C) / 361 min, holding 1800 °C / 150 min, heating (1800 - 1900 °C) / 180 min, holding 1900 °C / 150 min, heating (1900 - 2000 °C) / 240 min, holding 2000 °C / 120 min, heating (2000 - 2050 °C) / 180 min, holding 2050 °C / 300 min.

[0036] In the material selection of step (1), ammonium paratungstate and spherical ammonium paratungstate are mixed in a weight ratio of 4:1 - 1.5.

[0037] In the pre-reduction of step (2), there are cracks in the ammonium tungsten bronze, where the cracks account for more than 75% of the total surface area of the ammonium tungsten bronze.

[0038] In the pre-reduction of step (2), the temperatures of the four temperature zones are 300 °C - 330 °C, 390 °C - 410 °C, 410 °C - 430 °C, 430 °C - 450 °C respectively, the hydrogen flow rate is 0.3 m 3 / h - 0.4 m 3 / h, the pre-reduction loading amount is 720 g - 800 g, passing through a 20 - 100 mesh sieve, and the pushing speed is 10 - 20 min.

[0039] In the second stage of the vacuum spray doping in step (3), the contents of various substances are 2 - 3 parts by weight of potassium hydroxide, 4.5 - 5.5 parts by weight of silicic acid, and 1.8 - 3 parts by weight of aluminum nitrate solids are put into 50 - 70 L of water at 50 - 70 °C and completely dissolved, and then 0.5 - 2 L of dilute nitric acid is added.

[0040] In the second stage, the initial stages of the third and fourth stages of the vacuum spray doping in step (3), low-power vacuum pumping is used, and medium-high power vacuum pumping is used in the middle and late stages of the fourth stage; among them, the low power is 25% - 35% of the output power of the vacuum pumping equipment, and the medium-high power is 70% - 85% of the output power of the vacuum pumping equipment.

[0041] In the reduction step (4), the temperatures of the five-zone temperature reduction are 660°C to 680°C, 710°C to 740°C, 790°C to 820°C, 820°C to 840°C, and 840°C to 870°C respectively, the hydrogen flow rate is 4 m 3 / h to 7 m 3 / h, the loading amount is 350 g to 550 g, and the effective reduction time is 6 h to 8 h.

[0042] In the step (5) of batch pickling, it is sieved through a 150-170 mesh sieve to obtain pickled potassium-doped tungsten powder, and the effective potassium content in the pickled potassium-doped tungsten powder is 65 ppm to 80 ppm.

[0043] Preferably, in the second stage of the vacuum spray doping in step (3), the contents of each substance are 2-3 parts by weight of potassium hydroxide, 4.5-5.5 parts by weight of silicic acid, 1.8-3 parts by weight of aluminum nitrate solid, and 0.1-0.3 parts by weight of a functional agent. They are put into 50-70 L of water at 50-70°C and completely dissolved, and then 0.5-2 L of dilute nitric acid is added;

[0044] The preparation method of the functional agent is as follows, in parts by weight:

[0045] S1. Mix 25-35 parts of ZSM-5 molecular sieve with 35-45 parts of bentonite. Subsequently, add the mixture to 1400-1600 parts of 80-90 wt% phosphoric acid solution for impregnation treatment for 0.5-2 hours to promote the activation of the material surface; after the impregnation process is completed, remove the excess solution through filtration and washing with water, then perform drying treatment, add the dried powder to 1700-1900 parts of 60-80 wt% ethanol aqueous solution and mix, and then add 5-7 parts of 1-octylpyridinium bromide and 8-12 parts of calcium disodium EDTA for treatment; after the treatment is completed, obtain a pretreated product through filtration, washing, and drying;

[0046] S2. Disperse the pretreated product obtained in step 1 in 600-800 parts of water, then add 25-35 parts of tetraallyl silicate, 55-65 parts of diethylenetriamine, and 2-4 parts of cobalt chloride to form a uniform precursor solution; treat it at 90-98°C and 0.2-0.4 MPa for 1-3 hours, then through filtration, washing with water, and drying, and then perform calcination treatment at 300-500°C in a nitrogen atmosphere for 2-5 hours to obtain a post-treated product;

[0047] S3. Dissolve 35-45 parts of poly-1,2-propanediol and 25-35 parts of methyl acetoacetate in 600-800 parts of water to form a uniform solution; add 1-3 parts of 70-85 wt% sulfuric acid, under nitrogen protection, control the temperature at 80-95°C, and the treatment time is 3-10 hours; collect the liquid in the reactor to obtain the promoter;

[0048] S4. Mix 30 - 50 parts of the post - treated product obtained in step S2 with 140 - 160 parts of the promoter obtained in step S3, adjust the pH value to 9 - 10.5 with 10 - 18 wt% ammonia water, treat for 1 - 3 hours, and then adjust the pH value to 8 - 9 through ammonia distillation treatment to obtain the functional agent.

[0049] Compared with the prior art, it has the following beneficial effects:

[0050] 1) The present invention uses specially made high - activity potassium - doped tungsten powder with a narrow particle size range to produce tungsten rods. It not only eliminates the production scale effect limitation brought by particle size combination powder blending, improves the cold isostatic pressing effect, but more importantly, through the regulation of the narrow particle size range, in the sintering of the combination of vertical melting and medium - frequency, the potassium - doped tungsten billet obtains stable and nano - scale initial crystallization through vertical melting pretreatment, and then through the low - temperature and slow sintering of medium - frequency, its density reaches 18.1 g / cm 3 ~18.4 g / cm 3 At the same time, controlling the crystallization coarsening rate, the cross - section crystallization of the potassium - doped tungsten rod reaches 20,000 - 30,000 grains / mm 2 ~30,000 grains / mm 2 , and the grain size remains at 9 nm - 20 nm, reaching the micro - nano level.

[0051] 2) The tungsten rod products of the present invention are processed into tungsten wires with a diameter of 0.3 mm - 0.6 mm, the finished product rate reaches 88% - 90%, the qualified rate ≥ 95%, the tensile strength ≥ 2250 N / mm 2 , the high - temperature recrystallization temperature is 1850 °C - 2380 °C, the high - temperature sag value of the 0.39 mm specification ≤ 1.5 mm, the aspect ratio ≥ 15. At the same time, it has good high - temperature creep resistance. All parameters are completely superior to the same - type potassium - doped tungsten wires on the market. Wound into a 4 * 19 * 7 structure, the feedback is good, and the service life of the finished tungsten wire rope is more than 20% higher than that of the same - type products on the market.

[0052] 3) Adding the functional agent in the present invention can further improve the comprehensive performance of the doped tungsten rod, including enhancing the density and grain refinement degree of the material, improving the uniformity of potassium content and the mechanical strength of the product, so that the final tungsten wire rope shows higher flexibility, tensile strength and high - temperature stability. These improvements have significantly increased the service life of the tungsten wire rope compared with the existing products on the market. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 The potassium - doped tungsten rod prepared in Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0054] ZSM - 5 molecular sieve: Guangdong Shengke Biochemical Technology Co., Ltd., content: silica - alumina ratio 60%, product number: CS999673.

[0055] Bentonite: Lingshou County Tuyun Mineral Products Processing Plant, product specifications: 800 mesh, item number: p-025.

[0056] Kaolin: Lingshou County Qiangdong Mineral Products Processing Plant, product specifications: 800 mesh, item number: qd-909.

[0057] Montmorillonite: Guangzhou Yifeng Chemical Technology Co., Ltd., particle size: 50 nm, model: TY-710C.

[0058] Polypropylene glycol: Hubei Xinkang Pharmaceutical Chemical Co., Ltd., product number: XK2412.

[0059] The remaining raw materials in the examples and comparative examples of the present invention are all commercially available products.

[0060] The design idea of ​​the present invention is to achieve high performance of potassium-doped tungsten rods for high-flexibility tungsten wire ropes by finely controlling the manufacturing process of doped tungsten rods, including key steps such as raw material selection, pre-reduction, vacuum spray doping, reduction, pickling, mixing, molding, pre-sintering and medium-frequency sintering. In particular, the introduction of functional agents in the preparation of dopant solutions aims to improve the uniformity and reactivity of doping elements, optimize the microstructure and macroscopic properties of tungsten rods, and thus significantly improve the flexibility, tensile strength, high-temperature stability and service life of tungsten wire ropes, ensuring better performance and longer service life in harsh application environments.

[0061] Example 1

[0062] A method for manufacturing a potassium-doped tungsten rod for high-flexibility tungsten wire rope is as follows:

[0063] Take the production of 800kg batch of tungsten wire rope with diameter 19*600mm as an example:

[0064] (1) Material selection

[0065] The weight ratio of monoclinic ammonium paratungstate to spherical ammonium paratungstate is 4:1.2, and the obtained mixture is used as a raw material;

[0066] (2) Pre-reduction

[0067] The raw material of step (1) was pre-reduced in a four-zone temperature reduction furnace, the temperatures of the four zones were 310°C, 400°C, 420°C, and 450°C, the boat load was 750 g, and the hydrogen flow rate was 0.3 m 3 / h, pushing speed 15min; passing through a 40-mesh sieve, 1036kg of ammonium tungsten bronze with cracks on the surface was obtained, wherein the cracks accounted for 85% of the total surface area of ​​the ammonium tungsten bronze;

[0068] (3) Vacuum spray doping

[0069] It is divided into the following four stages:

[0070] In the first stage, 1036 kg of ammonium tungsten bronze after sieving is placed in a vacuum doping pot, and the vacuum is pumped to 350 Pa;

[0071] In the second stage, 2.31 kg of potassium hydroxide, 5.03 kg of silicic acid, and 2.17 kg of aluminum nitrate solid are respectively put into 60 L of deionized water at 60 °C and completely dissolved. Then 1 L of 4 mol / L dilute nitric acid is added, and the above solution is continuously stirred to prepare a dopant solution; the dopant solution is heated to 45 °C, and then slowly sprayed into the vacuum doping pot from the atomization holes. Open 1 / 4 of the atomization valve, and spray 1 / 3 of the dopant solution atomized within 1.5 h. Open 1 / 3 of the steam input valve, control the steam pressure to 0.15 Mpa, control the output power of the vacuum pump to 30%, and at this time, the materials in the pot must be kept turning, and the pot body is heated with steam to keep the temperature of the materials in the furnace at 72 °C;

[0072] In the third stage, increase the turning frequency of the pot body, keep the temperature in the furnace at 90 °C, and atomize and spray the remaining 2 / 3 of the dopant within 40 min. Open 2 / 3 of the steam input valve, control the steam pressure at 0.15 Mpa, and control the output power of the vacuum pump to 30%;

[0073] In the fourth stage, after the atomized spraying of all the dopants is completed, fully open the steam input valve, control the steam pressure at 0.25 Mpa, raise the temperature in the furnace to 110 °C, and continuously dry for 3.5 h to completely evaporate the water. Control the output power of the vacuum pump to 80%. When the vacuum degree in the vacuum doping pot remains at 450 Mpa, turn off the steam heating, and perform water cooling until the temperature in the furnace drops to 52 °C. Open the discharge valve and pass through a 40-mesh sieve to obtain 1041 kg of potassium-doped ammonium tungsten bronze;

[0074] (4) Reduction

[0075] Using a five-zone temperature reduction furnace, the 1041 kg of potassium-doped ammonium tungsten bronze obtained in step (3) is reduced once in a hydrogen atmosphere. The temperatures of the five zones are 670 °C, 725 °C, 810 °C, 830 °C, and 860 °C respectively, the hydrogen flow rate is 5 m 3 / h, the loading amount per boat is 450 g, the effective reduction time is 7 h, and 822 kg of potassium-doped tungsten powder with an average particle size of 3.1 μm is obtained, and the oxygen content of its powder is ≤700 ppm;

[0076] In the particle size distribution of the as-produced potassium-doped tungsten powder, the particle size D10 is 3.2 μm, the particle size D50 is 11.5 μm, and the particle size D90 is 28.5 μm; in the particle size distribution of the ground potassium-doped tungsten powder, the particle size D10 is 1.8 μm, the particle size D50 is 3.8 μm, and the particle size D90 is 7.8 μm;

[0077] (5) Batch pickling

[0078] The 822 kg of potassium-doped tungsten powder obtained in step (4) was successively washed with 4 mol / L dilute hydrochloric acid and 2 mL / L dilute hydrofluoric acid to remove the ineffective potassium content and other impurities in the potassium-doped tungsten powder. Subsequently, deionized water at 60 °C was used to remove the residual dilute hydrochloric acid and dilute hydrofluoric acid. Finally, the tungsten mud was dried in a vacuum box, and then the dried tungsten mud was re-crushed and passed through a 160-mesh sieve to finally obtain 814 kg of pickled potassium-doped tungsten powder with an effective potassium content of 72 ppm, Al ≤ 20 ppm, Si ≤ 20 ppm, and an oxygen content ≤ 800 ppm;

[0079] (6) Mixing

[0080] The 814 kg of pickled potassium-doped tungsten powder obtained in step (5) was placed in a high-speed mixer and mixed for 75 min under nitrogen protection. When cooled to 45 °C, it was unloaded and passed through a 180-mesh sieve to obtain 809 kg of potassium-doped compound powder;

[0081] (7) Hard membrane cold isostatic pressing

[0082] According to the requirement of 3000 g / root for single weight, it was loaded into a rubber hard mold sleeve with a length of 800 mm, an inner diameter of 25 mm, and a wall thickness of 2 mm. All 3000 g of potassium-doped compound powder was loaded into the mold sleeve by mechanical vibration, vibrated solid, and sealed tightly. It was placed in a cold isostatic press and pressed with a pressure of 145 Mpa to obtain 268 potassium-doped tungsten green compacts with a length of 670 mm, a diameter of 22.5 mm, and good appearance, and the long material rate was 100%;

[0083] (8) Low-temperature impurity removal

[0084] The 268 potassium-doped tungsten green compacts obtained in step (7) were placed in a hydrogen protection furnace at 1050 °C and fired for 50 min to obtain potassium-doped tungsten compacts with improved strength, without any fracture, and the long material rate was 100%;

[0085] (9) Plumbago pre-sintering

[0086] The 268 potassium-doped tungsten compacts obtained in step (8) were placed in a plumbago furnace for pre-sintering. Under hydrogen protection, they were electrically sintered to volatilize more than 95% of the impurities, reaching an average density of 15.78 g / cm 3 , and the initial crystal size obtained on the cross-section was 3.2 nm. The appearance was dark gray, and the crystallization was uniform in the upper and lower sections without any frame crystals;

[0087] The electrical sintering system was in sequence of heating up, heating up, heat preservation, heat preservation;

[0088] The current / time parameters are as follows: heating up (0 A to 2800 A) / 5 min, heating up (2800 A to 3850 A) / 6 min, heating up (3850 A to 4820 A) / 6 min, heat preservation (4820 A to 4820 A) / 21 min;

[0089] The hydrogen flow rate is 2.0 m 3 / h;

[0090] (10) Medium-frequency sintering

[0091] Place the 268 incompletely dense potassium-doped tungsten bars obtained in step (9) into the medium-frequency furnace, place the tungsten bars vertically in the stacking and sintering method, and sinter them in a hydrogen protection state using the double hydrogen inlet method at the bottom and top of the furnace. Use an infrared temperature measurement + PLC temperature control system to automatically control the sintering process; the sintering regime is in sequence of heating up, heat preservation, heating up, heat preservation, heating up, heat preservation, heating up, heat preservation, heating up, heat preservation, heating up, heat preservation; the temperature / time parameters are in sequence of: (0 to 1250 °C) / 430 min, heat preservation: 1250 °C / 90 min, heating up (1250 to 1500 °C) / 150 min, heat preservation 1500 °C / 120 min, heating up (1500 to 1800 °C) / 361 min, heat preservation 1800 °C / 150 min, heating up (1800 to 1900 °C) / 180 min, heat preservation 1900 °C / 150 min, heating up (1900 to 2000 °C) / 240 min, heat preservation 2000 °C / 120 min, heating up (2000 to 2050 °C) / 180 min, heat preservation 2050 °C / 300 min.

[0092] The finally obtained potassium-doped tungsten rods have an average density of 18.35 g / cm 3 , the potassium content is 58 ppm, the oxygen content is 8 ppm, the cross-sectional crystal number is 29872 pieces / mm 2 , and the average grain size is 12.8 nm, reaching the micro-nano level.

[0093] The potassium-doped tungsten rods in this embodiment are processed into tungsten wires with different specifications of 0.3 mm to 0.6 mm, the finished product rate reaches 88% to 90%, the qualified rate ≥ 95%, and the tensile strength ≥ 2250 N / mm 2 ; the high-temperature recrystallization temperature ≥ 1850 °C, the high-temperature sag value of the 0.39 mm specification ≤ 1.5 mm, the aspect ratio ≥ 15, it does not crack when bent 90 degrees and then straightened at room temperature, and the results of each parameter are better than those of the same type of potassium-doped tungsten wires on the market. The 4*19*7 structure is wound and the feedback is good; and after statistics, the service life of the tungsten wire rope finished product is more than 20% higher than that of the same type of products on the market.

[0094] Example 2

[0095] The manufacturing method of potassium-doped tungsten rods for highly flexible tungsten wire ropes is basically the same as that of Example 1, and the only difference lies in the preparation method of the dopant solution in the second stage of step (3).

[0096] The preparation method of the dopant solution is as follows:

[0097] Dissolve 2.31 kg of potassium hydroxide, 5.03 kg of silicic acid, 2.17 kg of aluminum nitrate solid, and 0.2 kg of functional agent in 60 L of deionized water at 60 °C completely, and then add 1 L of 4 mol / L dilute nitric acid, and continue to stir the above solution to prepare the dopant solution.

[0098] The preparation method of the functional agent is as follows:

[0099] S1. Mix 30 g of ZSM-5 molecular sieve with 40 g of bentonite, and then add the mixture to 1500 g of 85 wt% phosphoric acid solution for impregnation treatment for 1 hour to promote the activation of the material surface; after the impregnation process is completed, remove the excess solution through filtration and washing with water, and then perform drying treatment. Add the dried powder to 1800 g of 70 wt% ethanol aqueous solution and mix, and then add 6 g of 1-octylpyridinium bromide and 10 g of EDTA disodium calcium for treatment; after the treatment is completed, obtain the pretreated product through filtration, washing, and drying;

[0100] S2. Disperse the pretreated product obtained in step 1 in 700 g of water, and then add 30 g of tetraallyl silicate, 60 g of diethylenetriamine, and 3 g of cobalt chloride to form a uniform precursor solution; treat it at 95 °C and 0.3 MPa for 2 hours, and then obtain the post-treated product through filtration, washing with water, and drying, and then perform calcination treatment at 400 °C for 4 hours under a nitrogen atmosphere;

[0101] S3. Dissolve 40 g of poly-1,2-propanediol and 30 g of methyl acetoacetate in 700 g of water to form a uniform solution; add 2 g of 80 wt% sulfuric acid, under nitrogen protection, control the temperature at 90 °C, and the treatment time is 6 hours; collect the liquid in the reactor to obtain the promoter;

[0102] S4. Mix 40 g of the post-treated product obtained in step S2 with 150 g of the promoter obtained in step S3, adjust the pH value to 10 with 15 wt% ammonia water, treat for 2 hours, and then adjust the pH value to 8.5 through ammonia evaporation treatment to obtain the functional agent.

[0103] The finally obtained potassium-doped tungsten rod has an average density of 18.49 g / cm 3 , the potassium content is 59 ppm, the oxygen content is 9 ppm, and the cross-sectional crystal number is 29946 pieces / mm 2, the average grain size is 11.6 nm, reaching the micro-nano level.

[0104] The potassium-doped tungsten rods of this embodiment are processed into tungsten wires of different specifications from 0.3 mm to 0.6 mm. The finished product rate reaches 90% - 92%, the qualified rate is ≥ 97%, and the tensile strength is ≥ 2376 N / mm 2 ; the high-temperature recrystallization temperature is ≥ 1880 °C, the high-temperature sag value of the 0.39 mm specification is ≤ 1.2 mm, the aspect ratio is ≥ 17, and it does not crack when bent 90 degrees at room temperature and then straightened. The results of all parameters are better than those of the same type of potassium-doped tungsten wires on the market. Wound into a 4*19*7 structure, the feedback is good; and after statistics, the service life of the finished tungsten wire rope is more than 25% higher than that of the same type of products on the market.

[0105] Example 3

[0106] The manufacturing method of the potassium-doped tungsten rod for a highly flexible tungsten wire rope is basically the same as that of Example 1, and the only difference lies in the preparation method of the dopant solution in the second stage of step (3).

[0107] The preparation method of the dopant solution is as follows:

[0108] Dissolve 2.31 kg of potassium hydroxide, 5.03 kg of silicic acid, 2.17 kg of aluminum nitrate solid, and 0.2 kg of functional agent in 60 L of deionized water at 60 °C completely, then add about 1 L of dilute nitric acid, and continue to stir the above solution to prepare the dopant solution.

[0109] The preparation method of the functional agent is as follows:

[0110] S1. Mix 30 g of ZSM-5 molecular sieve with 40 g of kaolin, and then add the mixture to 1500 g of 85 wt% phosphoric acid solution for impregnation treatment for 1 hour to promote the activation of the material surface; after the impregnation process ends, remove the excess solution through filtration and washing with water, then carry out drying treatment, add the dried powder to 1800 g of 70 wt% ethanol aqueous solution for mixing, and then add 6 g of 1-octylpyridinium bromide and 10 g of EDTA disodium calcium for treatment; after the treatment is completed, obtain the pretreatment through filtration, washing and drying.

[0111] S2. Disperse the pretreatment obtained in step 1 in 700 g of water, then add 30 g of tetraallyl silicate, 60 g of diethylenetriamine and 3 g of cobalt chloride to form a uniform precursor solution; treat it at 95 °C and 0.3 MPa for 2 hours, then through filtration, washing with water and drying, and then carry out calcination treatment at 400 °C in a nitrogen atmosphere for 4 hours to obtain the post-treatment.

[0112] S3. Dissolve 40 g of poly(1,2-propanediol) and 30 g of methyl acetoacetate in 700 g of water to form a homogeneous solution; add 2 g of 80 wt% sulfuric acid, under nitrogen protection, control the temperature at 90 °C, and the treatment time is 6 hours; collect the liquid in the reactor to obtain the promoter.

[0113] S4. Mix 40 g of the post-treated product obtained in step S2 with 150 g of the promoter obtained in step S3, adjust the pH value to 10 with 15 wt% ammonia water, treat for 2 hours, and then adjust the pH value to 8.5 by ammonia distillation treatment to obtain the functional agent.

[0114] The finally obtained potassium-doped tungsten rod has an average density of 18.43 g / cm 3 , the potassium content is 57 ppm, the oxygen content is 8 ppm, and the number of crystal grains per cross-section is 29906 / mm 2 , and the average grain size is 12.1 nm, reaching the micro-nano level.

[0115] The potassium-doped tungsten rod of this example is processed into tungsten wires of different specifications from 0.3 mm to 0.6 mm, the finished product rate reaches 89% - 91%, the qualified rate ≥ 95%, and the tensile strength ≥ 2343 N / mm 2 ; the high-temperature recrystallization temperature ≥ 1872 °C, the high-temperature sag value of the 0.39 mm specification ≤ 1.3 mm, the aspect ratio ≥ 15, it can be bent 90 degrees at room temperature and then straightened without cracking, and the results of various parameters are better than those of the same type of potassium-doped tungsten wires on the market. The 4*19*7 structure is wound and the feedback is good; and after statistics, the service life of the finished tungsten wire rope is more than 23% higher than that of the same type of products on the market.

[0116] Example 4

[0117] A manufacturing method of a potassium-doped tungsten rod for a highly flexible tungsten wire rope is basically the same as that of Example 1, and the only difference is the preparation method of the dopant solution in the second stage of step (3).

[0118] The preparation method of the dopant solution is as follows:

[0119] Dissolve 2.31 kg of potassium hydroxide, 5.03 kg of silicic acid, 2.17 kg of aluminum nitrate solid, and 0.2 kg of functional agent in 60 L of deionized water at 60 °C completely, and then add about 1 L of dilute nitric acid, and continue to stir the above solution to prepare the dopant solution.

[0120] The preparation method of the functional agent is as follows:

[0121] S1. Mix 30 g of ZSM-5 molecular sieve with 40 g of montmorillonite. Subsequently, add the mixture to 1500 g of 85 wt% phosphoric acid solution for impregnation treatment for 1 hour to promote the activation of the material surface. After the impregnation process is completed, remove the excess solution through filtration and washing with water. Then, conduct a drying treatment. Add the dried powder to 1800 g of 70 wt% ethanol aqueous solution for mixing. Subsequently, add 6 g of 1-octylpyridinium bromide and 10 g of calcium disodium EDTA for treatment. After the treatment is completed, obtain the pretreated material through filtration, washing, and drying.

[0122] S2. Disperse the pretreated material obtained in step 1 in 700 g of water. Then, add 30 g of tetraallyl silicate, 60 g of diethylenetriamine, and 3 g of cobalt chloride to form a uniform precursor solution. Treat it under the conditions of 95 °C and 0.3 MPa for 2 hours. Then, through filtration, washing with water, and drying, and then conduct a calcination treatment at 400 °C for 4 hours under a nitrogen atmosphere to obtain the post-treated material.

[0123] S3. Dissolve 40 g of poly-1,2-propanediol and 30 g of methyl acetoacetate in 700 g of water to form a uniform solution. Add 2 g of 80 wt% sulfuric acid. Under nitrogen protection, control the temperature at 90 °C and the treatment time at 6 hours. Collect the liquid in the reactor to obtain the promoter.

[0124] S4. Mix 40 g of the post-treated material obtained in step S2 with 150 g of the promoter obtained in step S3. Adjust the pH value to 10 with 15 wt% ammonia water and treat for 2 hours. Then, adjust the pH value to 8.5 through ammonia evaporation treatment to obtain the functional agent.

[0125] The finally obtained potassium-doped tungsten rod has an average density of 18.42 g / cm 3 , a potassium content of 57 ppm, an oxygen content of 8 ppm, and a cross-sectional crystal count of 29908 / mm 2 , with an average grain size of 12.2 nm, reaching the micro-nano level.

[0126] The potassium-doped tungsten rods in this example are processed into tungsten wires with different specifications of 0.3 mm to 0.6 mm. The finished product rate reaches 89% to 91%, the qualified rate ≥ 95%, and the tensile strength ≥ 2362 N / mm 2 ; the high-temperature recrystallization temperature ≥ 1865 °C, the high-temperature sag value of the 0.39 mm specification ≤ 1.3 mm, the aspect ratio ≥ 16, and it does not crack when bent 90 degrees and then straightened at room temperature. The results of all parameters are better than those of the same type of potassium-doped tungsten wires on the market. The winding structure is 4*19*7, and the feedback is good. And through statistics, the service life of the finished tungsten wire rope is more than 22% higher than that of the same type of products on the market.

[0127] Example 5

[0128] The manufacturing method of the potassium-doped tungsten rod for a highly flexible tungsten wire rope is basically the same as that of Example 1, and the only difference lies in the preparation method of the dopant solution in the second stage of step (3).

[0129] The preparation method of the dopant solution is as follows:

[0130] Dissolve 2.31 kg of potassium hydroxide, 5.03 kg of silicic acid, 2.17 kg of aluminum nitrate solid, and 0.2 kg of functional agent in 60 L of deionized water at 60 °C completely, then add about 1 L of dilute nitric acid, and continue to stir the above solution to prepare the dopant solution.

[0131] The preparation method of the functional agent is as follows:

[0132] S1. Mix 30 g of ZSM-5 molecular sieve with 40 g of bentonite, and then add the mixture to 1500 g of 85 wt% phosphoric acid solution for impregnation treatment for 1 hour to promote the activation of the material surface; after the impregnation process is completed, remove the excess solution through filtration and washing with water, then perform drying treatment, add the dried powder to 1800 g of 70 wt% ethanol aqueous solution for mixing, and then add 6 g of 1-octylpyridinium bromide and 10 g of calcium disodium EDTA for treatment; after the treatment is completed, obtain the pretreated product through filtration, washing, and drying;

[0133] S2. Disperse the pretreated product obtained in step 1 in 700 g of water, then add 30 g of tetraallyl silicate, 60 g of diethylenetriamine, and 3 g of nickel nitrate to form a uniform precursor solution; treat it at 95 °C and 0.3 MPa for 2 hours, then filter, wash with water, and dry, and then perform calcination treatment at 400 °C for 4 hours under a nitrogen atmosphere to obtain the post-treated product;

[0134] S3. Dissolve 40 g of poly-1,2-propanediol and 30 g of methyl acetoacetate in 700 g of water to form a uniform solution; add 2 g of 80 wt% sulfuric acid, under nitrogen protection, control the temperature at 90 °C, and the treatment time is 6 hours; collect the liquid in the reactor to obtain the promoter;

[0135] S4. Mix 40 g of the post-treated product obtained in step S2 with 150 g of the promoter obtained in step S3, adjust the pH value to 10 with 15 wt% ammonia water, treat for 2 hours, and then adjust the pH value to 8.5 through ammonia evaporation treatment to obtain the functional agent.

[0136] The finally obtained potassium-doped tungsten rod has an average density of 18.39 g / cm 3 , the potassium content is 58 ppm, the oxygen content is 8 ppm, the cross-sectional crystal number is 29913 pieces / mm 2 , and the average grain size is 12.4 nm, reaching the micro-nano level.

[0137] The potassium-doped tungsten rods of this embodiment are processed into tungsten wires with different specifications of 0.3 mm to 0.6 mm, and the yield rate reaches 89% to 91%, the qualification rate ≥ 96%, and the tensile strength ≥ 2335 N / mm 2 ; the high-temperature recrystallization temperature ≥ 1869 °C, the high-temperature sag value of the 0.39 mm specification ≤ 1.3 mm, the aspect ratio ≥ 15, and it does not crack when bent 90 degrees and then straightened at room temperature. The results of each parameter are better than those of the same type of potassium-doped tungsten wires on the market. The 4*19*7 structure is wound and the feedback is good; and after statistics, the service life of the finished tungsten wire rope is more than 23% higher than that of the same type of products on the market.

[0138] Example 6

[0139] A manufacturing method of potassium-doped tungsten rods for high-flexibility tungsten wire ropes is basically the same as that of Example 1, and the only difference lies in the preparation method of the dopant solution in the second stage of step (3).

[0140] The preparation method of the dopant solution is as follows:

[0141] Dissolve 2.31 kg of potassium hydroxide, 5.03 kg of silicic acid, 2.17 kg of aluminum nitrate solid, and 0.2 kg of functional agent into 60 L of deionized water at 60 °C completely, then add about 1 L of dilute nitric acid, and continue to stir the above solution to prepare the dopant solution.

[0142] The preparation method of the functional agent is as follows:

[0143] S1. Mix 30 g of ZSM-5 molecular sieve with 40 g of bentonite, and then add the mixture to 1500 g of 85 wt% phosphoric acid solution for impregnation treatment for 1 hour to promote the activation of the material surface; after the impregnation process ends, remove the excess solution through filtration and washing with water, then perform drying treatment, add the dried powder to 1800 g of 70 wt% ethanol aqueous solution and mix, then add 6 g of 1-octylpyridinium bromide and 10 g of EDTA disodium calcium for treatment; after the treatment is completed, obtain the pretreatment through filtration, washing and drying.

[0144] S2. Disperse the pretreatment obtained in step 1 in 700 g of water, then add 30 g of tetraallyl silicate, 60 g of diethylenetriamine and 3 g of zinc nitrate to form a uniform precursor solution; treat it at 95 °C and 0.3 MPa for 2 hours, then through filtration, washing with water and drying, and then perform calcination treatment at 400 °C in a nitrogen atmosphere for 4 hours to obtain the post-treatment.

[0145] S3. Dissolve 40 g of poly(1,2 - propanediol) and 30 g of methyl acetoacetate in 700 g of water to form a homogeneous solution; add 2 g of 80 wt% sulfuric acid, under nitrogen protection, control the temperature at 90 °C, and the treatment time is 6 hours; collect the liquid in the reactor to obtain the promoter.

[0146] S4. Mix 40 g of the post - treated product obtained in step S2 with 150 g of the promoter obtained in step S3, adjust the pH value to 10 with 15 wt% ammonia water, treat for 2 hours, and then adjust the pH value to 8.5 through ammonia evaporation treatment to obtain the functional agent.

[0147] The finally obtained potassium - doped tungsten rod has an average density of 18.40 g / cm 3 , the potassium content is 59 ppm, the oxygen content is 8 ppm, and the number of crystal grains per cross - section is 29911 grains / mm 2 , the average grain size is 12.4 nm, reaching the micro - nano level.

[0148] The potassium - doped tungsten rods of this example are processed into tungsten wires of different specifications from 0.3 mm to 0.6 mm. The finished product rate reaches 90% - 92%, the qualified rate ≥ 96%, and the tensile strength ≥ 2350 N / mm 2 ; the high - temperature recrystallization temperature ≥ 1878 °C, the high - temperature sag value of the 0.39 - mm specification ≤ 1.4 mm, the aspect ratio ≥ 16, it can be bent 90 degrees at room temperature and then straightened without cracking. The results of all parameters are better than those of the same - type potassium - doped tungsten wires on the market. When winding a 4*19*7 structure, the feedback is good; and through statistics, the service life of the finished tungsten wire rope is more than 23% higher than that of the same - type products on the market.

[0149] Example 7

[0150] A manufacturing method of a potassium - doped tungsten rod for a highly flexible tungsten wire rope is basically the same as that of Example 1, and the only difference lies in the preparation method of the dopant solution in the second stage of step (3).

[0151] The preparation method of the dopant solution is as follows:

[0152] Dissolve 2.31 kg of potassium hydroxide, 5.03 kg of silicic acid, 2.17 kg of aluminum nitrate solid, and 0.2 kg of the functional agent into 60 L of deionized water at 60 °C completely, and then add about 1 L of dilute nitric acid, and continue to stir the above solution to prepare the dopant solution.

[0153] The preparation method of the functional agent is as follows:

[0154] S1. Mix 30 g of ZSM-5 molecular sieve with 40 g of bentonite. Subsequently, add the mixture to 1500 g of 85 wt% phosphoric acid solution for impregnation treatment for 1 hour to promote the activation of the material surface. After the impregnation process, remove the excess solution through filtration and washing with water, then conduct a drying treatment. Add the dried powder to 1800 g of 70 wt% ethanol aqueous solution for mixing, and then add 6 g of 1-octylpyridinium bromide and 10 g of EDTA disodium calcium for treatment. After the treatment is completed, obtain the pre-treated product through filtration, washing, and drying.

[0155] S2. Disperse the pre-treated product obtained in step 1 in 700 g of water, then add 30 g of tetraallyl silicate, 60 g of diethylenetriamine, and 3 g of manganese sulfate to form a uniform precursor solution. Treat it at 95 °C and 0.3 MPa for 2 hours, then filter, wash with water, and dry. Then, conduct a calcination treatment at 400 °C for 4 hours in a nitrogen atmosphere to obtain the post-treated product.

[0156] S3. Dissolve 40 g of poly-1,2-propanediol and 30 g of methyl acetoacetate in 700 g of water to form a uniform solution. Add 2 g of 80 wt% sulfuric acid, under nitrogen protection, control the temperature at 90 °C, and the treatment time is 6 hours. Collect the liquid in the reactor to obtain the promoter.

[0157] S4. Mix 40 g of the post-treated product obtained in step S2 with 150 g of the promoter obtained in step S3, adjust the pH value to 10 with 15 wt% ammonia water, treat for 2 hours, and then adjust the pH value to 8.5 through ammonia evaporation treatment to obtain the functional agent.

[0158] The finally obtained potassium-doped tungsten rod has an average density of 18.48 g / cm 3 , a potassium content of 58 ppm, an oxygen content of 9 ppm, and a cross-sectional crystal count of 29915 per mm 2 , with an average grain size of 12.5 nm, reaching the micro-nano level.

[0159] The potassium-doped tungsten rod of this example is processed into tungsten wires of different specifications from 0.3 mm to 0.6 mm. The yield rate reaches 90% - 92%, the qualified rate ≥ 96%, and the tensile strength ≥ 2353 N / mm 2 ; the high-temperature recrystallization temperature ≥ 1879 °C, the high-temperature sag value of the 0.39 mm specification ≤ 1.3 mm, the aspect ratio ≥ 16, it does not crack when bent 90 degrees and then straightened at room temperature. The results of various parameters are better than those of the same type of potassium-doped tungsten wire on the market. Wound into a 4*19*7 structure, the feedback is good; and through statistics, the service life of the tungsten wire rope finished product is more than 23% higher than that of the same type of product on the market.

[0160] Comparative Example 1

[0161] The manufacturing method of potassium-doped tungsten rods for high-flexibility tungsten wire ropes is basically the same as that of Example 1, and the only difference is that in step (1), ammonium metatungstate and spherical ammonium paratungstate are mixed at a weight ratio of 4:0.9.

[0162] The finally obtained potassium-doped tungsten rods have an average density of 17.92 g / cm 3 , a potassium content of 56 ppm, an oxygen content of 8 ppm, and 10,872 crystal grains per mm 2 in the cross section, and the average grain size is 21.2 nm.

[0163] The potassium-doped tungsten rods of this comparative example are processed into tungsten wires of different specifications from 0.3 mm to 0.6 mm. The finished product rate is statistically 68% - 72%, 52.8% ≤ qualified rate ≤ 78.3%, 980 N / mm 2 ≤ tensile strength ≤ 1850 N / mm 2 ; 1080°C ≤ high-temperature recrystallization temperature ≤ 1350°C, the high-temperature sag value of the 0.39 mm specification ≤ 5.5 mm, the aspect ratio ≤ 12, cracking occurs when bent 90 degrees at room temperature and then straightened, winding a 4*19*7 structure, and the service life of the finished tungsten wire rope has no obvious difference from that of similar products in the market.

[0164] Comparative Example 2

[0165] The manufacturing method of potassium-doped tungsten rods for high-flexibility tungsten wire ropes is basically the same as that of Example 1, and the only difference is that in step (1), ammonium metatungstate and spherical ammonium paratungstate are mixed at a weight ratio of 4:1.6.

[0166] The finally obtained potassium-doped tungsten rods have an average density of 16.92 g / cm 3 , a potassium content of 62 ppm, an oxygen content of 10 ppm, and 10,928 crystal grains per mm 2 in the cross section, and the average grain size is 21.6 nm.

[0167] The potassium-doped tungsten rods of this comparative example are processed into tungsten wires of different specifications from 0.3 mm to 0.6 mm. The finished product rate is statistically 69% - 74%, 55.1% ≤ qualified rate ≤ 78.9%, 985 N / mm 2 ≤ tensile strength ≤ 1780 N / mm 2 ; 1080°C ≤ high-temperature recrystallization temperature ≤ 1350°C, 3.8 mm ≤ high-temperature sag value of the 0.39 mm specification ≤ 5.5 mm, the aspect ratio ≤ 12, cracking occurs when bent 90 degrees at room temperature and then straightened, winding a 4*19*7 structure, and the service life of the finished tungsten wire rope has no obvious difference from that of similar products in the market.

[0168] It can be seen from Example 1 and Comparative Examples 1-2 that the morphology of ammonium paratungstate has a great influence on the properties of subsequent tungsten oxide, tungsten powder, and tungsten carbide. Selecting different crystal forms of ammonium paratungstate and mixing them as raw materials can directly reduce and process them by a subsequent special reduction process to obtain a good normal distribution of a mixture of thick and fine doped tungsten powders, and at the same time avoid the mixed tungsten powder with spike-shaped or bimodal phenomena, making the properties of tungsten wires after processing tungsten bars all excellent.

[0169] Comparative Example 3

[0170] A method for manufacturing a potassium-doped tungsten rod for a highly flexible tungsten wire rope is basically the same as that in Example 1, and the only difference is that in step (2), ammonium tungsten bronze with cracks on the surface is obtained, wherein the cracks account for 74% of the total surface area of the ammonium tungsten bronze.

[0171] The finally obtained potassium-doped tungsten rod has an average density of 15.92 g / cm 3 , the potassium content is 80 ppm, the oxygen content is 10 ppm, and the number of crystal grains per cross-section is 12,928 / mm 2 , and the average grain size is 17.5 nm.

[0172] The potassium-doped tungsten rods of this comparative example are processed into tungsten wires of different specifications from 0.3 mm to 0.6 mm, and the yield rate is statistically 68% - 72%, 55.2% ≤ qualification rate ≤ 78.1%, 985 N / mm 2 ≤ tensile strength ≤ 1780 N / mm 2 ; 1080 °C ≤ high-temperature recrystallization temperature ≤ 1350 °C, 3.8 mm ≤ high-temperature sag value of 0.39 mm specification ≤ 5.5 mm, aspect ratio ≤ 12, cracking occurs when bent 90 degrees at room temperature and then straightened, wound into a 4*19*7 structure, and the service life of the finished tungsten wire rope has no obvious difference from that of similar products in the market.

[0173] It can be seen from Example 1 and Comparative Example 3 that by using specific process conditions to pre-reduce ammonium paratungstate into a special intermediate ammonium tungsten bronze (ATB), because there are many fine cracks in ATB, it is beneficial for the doping agent solution to penetrate deep inside. In addition, the appropriate amount of NH 4+ in ATB is also beneficial for the incorporation of K + , and at the same time, ATB has good surface activity, effectively solving the problems of low density, few crystal grains, difficult processing, low yield rate of tungsten bars obtained by conventional methods, and causing organizational structure deterioration, high plastic-brittle transition temperature, and poor high-temperature anti-sag performance.

[0174] Comparative Example 4

[0175] A method for manufacturing a potassium-doped tungsten rod for a highly flexible tungsten wire rope is basically the same as that in Example 1, and the only difference is that in step (3), the addition amount of potassium hydroxide in the second-stage doping agent solution is 2 kg.

[0176] The finally obtained potassium-doped tungsten rod has an average density of 15.28 g / cm 3 , a potassium content of 63 ppm, an oxygen content of 9 ppm, and 9896 crystal grains per mm 2 in the cross-section, and the average grain size is 25.1 nm.

[0177] The potassium-doped tungsten rods of this comparative example were processed into tungsten wires of different specifications from 0.3 mm to 0.6 mm. The yield rate was statistically 69% - 74%, 55.1% ≤ the qualified rate ≤ 78.9%, 985 N / mm 2 ≤ the tensile strength ≤ 1780 N / mm 2 ; 1080°C ≤ the high-temperature recrystallization temperature ≤ 1350°C, 3.8 mm ≤ the high-temperature sag value of the 0.39 mm specification ≤ 5.5 mm, the aspect ratio ≤ 12, cracking occurred when bent 90 degrees at room temperature and then straightened, wound into a 4*19*7 structure, and the service life of the finished tungsten wire rope has no obvious difference from that of the same type of products in the market.

[0178] Comparative Example 5

[0179] A method for manufacturing a potassium-doped tungsten rod for a highly flexible tungsten wire rope is basically the same as that of Example 1. The only difference is that in the doping agent solution in the second stage of step (3), the addition amount of potassium hydroxide is 2.5 kg.

[0180] The finally obtained potassium-doped tungsten rod has an average density of 18.0 g / cm 3 , a potassium content of 81 ppm, an oxygen content of 8 ppm, and 10105 crystal grains per mm 2 in the cross-section, and the average grain size is 21.5 nm.

[0181] The potassium-doped tungsten rods of this comparative example were processed into tungsten wires of different specifications from 0.3 mm to 0.6 mm. The yield rate was statistically 69% - 74%, 55.1% ≤ the qualified rate ≤ 78.9%, 985 N / mm 2 ≤ the tensile strength ≤ 1780 N / mm 2 ; 1080°C ≤ the high-temperature recrystallization temperature ≤ 1350°C, 3.8 mm ≤ the high-temperature sag value of the 0.39 mm specification ≤ 5.5 mm, the aspect ratio ≤ 12, cracking occurred when bent 90 degrees at room temperature and then straightened, wound into a 4*19*7 structure, and the service life of the finished tungsten wire rope has no obvious difference from that of the same type of products in the market.

[0182] Comparative Example 6

[0183] A method for manufacturing a potassium-doped tungsten rod for a highly flexible tungsten wire rope is basically the same as that of Example 1. The only difference is that in the doping agent solution in the second stage of step (3), the addition amount of silicic acid is 4.6 kg.

[0184] The finally obtained potassium-doped tungsten rod has an average density of 14.92 g / cm 3 , a potassium content of 65 ppm, an oxygen content of 10 ppm, and 10,743 crystal grains per mm of the cross section 2 , and the average grain size is 18.7 nm.

[0185] The potassium-doped tungsten rods in this comparative example were processed into tungsten wires of different specifications from 0.3 mm to 0.6 mm. The finished product rate was statistically 65% - 72%, 55.1% ≤ qualified rate ≤ 78.9%, 985 N / mm 2 ≤ tensile strength ≤ 1780 N / mm 2 ; 980 °C ≤ high-temperature recrystallization temperature ≤ 1250 °C, 3.8 mm ≤ high-temperature sag value of 0.39 mm specification ≤ 5.5 mm, aspect ratio ≤ 12. When bent 90 degrees at room temperature and then straightened, cracking occurs. When winding a 4*19*7 structure, the service life of the finished tungsten wire rope has no obvious difference from that of similar products in the market.

[0186] Comparative Example 7

[0187] A manufacturing method of a potassium-doped tungsten rod for a highly flexible tungsten wire rope is basically the same as that of Example 1. The only difference is that in the second-stage dopant solution in step (3), the addition amount of silicic acid is 5.4 kg.

[0188] The finally obtained potassium-doped tungsten rod has an average density of 17.09 g / cm 3 , a potassium content of 63 ppm, an oxygen content of 10 ppm, and 10,928 crystal grains per mm of the cross section 2 , and the average grain size is 21.6 nm.

[0189] The potassium-doped tungsten rods in this comparative example were processed into tungsten wires of different specifications from 0.3 mm to 0.6 mm. The finished product rate was statistically 68% - 72%, 54.9% ≤ qualified rate ≤ 72.7%, 975 N / mm 2 ≤ tensile strength ≤ 1480 N / mm 2 ; 1000 °C ≤ high-temperature recrystallization temperature ≤ 1050 °C, 3.8 mm ≤ high-temperature sag value of 0.39 mm specification ≤ 5.5 mm, aspect ratio ≤ 12. When bent 90 degrees at room temperature and then straightened, cracking occurs. When winding a 4*19*7 structure, the service life of the finished tungsten wire rope has no obvious difference from that of similar products in the market.

[0190] Comparative Example 8

[0191] A manufacturing method of a potassium-doped tungsten rod for a highly flexible tungsten wire rope is basically the same as that of Example 1. The only difference is that in the second-stage dopant solution in step (3), the addition amount of aluminum nitrate is 1.9 kg.

[0192] The finally obtained potassium-doped tungsten rod has an average density of 16.82 g / cm 3 , a potassium content of 65 ppm, an oxygen content of 10 ppm, and 9825 crystal grains per mm of cross-section 2 , and the average grain size is 20.9 nm.

[0193] The potassium-doped tungsten rods of this comparative example were processed into tungsten wires of different specifications from 0.3 mm to 0.6 mm. The yield rate was statistically 63% - 71%, 56.2% ≤ qualified rate ≤ 74.3%, 850 N / mm 2 ≤ tensile strength ≤ 1580 N / mm 2 ; 1050 °C ≤ high-temperature recrystallization temperature ≤ 1250 °C, 3.8 mm ≤ high-temperature sag value of 0.39 mm specification ≤ 5.5 mm, aspect ratio ≤ 12. When bent 90 degrees at room temperature and then straightened, cracking occurs. Wound into a 4*19*7 structure, the service life of the finished tungsten wire rope has no obvious difference from that of similar products in the market.

[0194] Comparative Example 9

[0195] A manufacturing method of a potassium-doped tungsten rod for a highly flexible tungsten wire rope is basically the same as that of Example 1. The only difference is that in the doping agent solution in the second stage of step (3), the addition amount of aluminum nitrate is 2.3 kg.

[0196] The finally obtained potassium-doped tungsten rod has an average density of 16.75 g / cm 3 , a potassium content of 62 ppm, an oxygen content of 10 ppm, and 10121 crystal grains per mm of cross-section 2 , and the average grain size is 21.6 nm.

[0197] The potassium-doped tungsten rods of this comparative example were processed into tungsten wires of different specifications from 0.3 mm to 0.6 mm. The yield rate was statistically 69% - 74%, 55.1% ≤ qualified rate ≤ 78.9%, 985 N / mm 2 ≤ tensile strength ≤ 1780 N / mm 2 ; 1060 °C ≤ high-temperature recrystallization temperature ≤ 1250 °C, 4.2 mm ≤ high-temperature sag value of 0.39 mm specification ≤ 5.8 mm, aspect ratio ≤ 12. When bent 90 degrees at room temperature and then straightened, cracking occurs. Wound into a 4*19*7 structure, the service life of the finished tungsten wire rope has no obvious difference from that of similar products in the market.

[0198] It can be seen from Example 1 and Comparative Examples 4 - 9 that in the present invention, potassium hydroxide, silicic acid, and aluminum nitrate are used for doping to prepare a mixed solution of potassium silicate and aluminum nitrate. Elements such as aluminum and silicon can promote the entry of potassium elements into the tungsten matrix, thereby significantly reducing the low-temperature brittleness of tungsten wires, reducing tungsten wire splitting, and enabling the prepared tungsten wires to have good high-temperature anti-sag performance.

[0199] Comparative Example 10

[0200] The manufacturing method of potassium-doped tungsten rods for high-flexibility tungsten wire ropes is basically the same as that of Example 1, and the only difference is that step (3) is divided into three stages:

[0201] The first stage is the same as that of Example 1;

[0202] In the second stage, 2.31 kg of potassium hydroxide, 5.03 kg of silicic acid, and 2.17 kg of aluminum nitrate solid are respectively put into 60 L of deionized water at 60 °C and completely dissolved, then 1 L of dilute nitric acid is added, and the above solution is continuously stirred to prepare a dopant solution; the dopant solution is heated to 45 °C, and then slowly sprayed into the atomization holes of the vacuum doping pot. Open 1 / 4 of the atomization valve, and atomize and spray 1 / 3 of the dopant solution within 1.5 h. Open 1 / 3 of the steam input valve, control the steam pressure to 0.15 Mpa, and control the output power of the vacuum pump to 30%. At this time, the materials in the pot must be kept turning, and the pot body is heated with steam to keep the temperature of the materials in the furnace at 90 °C;

[0203] In the third stage, the temperature in the furnace is raised to 110 °C to completely evaporate the water and obtain potassium-doped ammonium tungsten bronze.

[0204] The finally obtained potassium-doped tungsten rod has an average density of 12.92 g / cm 3 , the potassium content is 58 ppm, the oxygen content is 10 ppm, the number of crystal grains on the cross section is 8762 grains / mm 2 , and the average grain size is 35.9 nm.

[0205] The potassium-doped tungsten rods of this comparative example are processed into tungsten wires of different specifications from 0.3 mm to 0.6 mm. The yield rate is statistically 62% - 70%, 52.1% ≤ qualified rate ≤ 71.9%, 905 N / mm 2 ≤ tensile strength ≤ 1120 N / mm 2 ; 789 °C ≤ high-temperature recrystallization temperature ≤ 1050 °C, 4.8 mm ≤ high-temperature sag value of 0.39 mm specification ≤ 6.9 mm, aspect ratio ≤ 12. When bent 90 degrees at room temperature and then straightened, cracking occurs. When winding a 4*19*7 structure, the service life of the tungsten wire rope finished product has no obvious difference from that of similar products in the market.

[0206] Comparative Example 11

[0207] The manufacturing method of potassium-doped tungsten rods for high-flexibility tungsten wire ropes is basically the same as that of Example 1, and the only difference is that in the second, third, and fourth stages of step (3), low-power vacuum pumping is used, and the output power of the vacuum pump is controlled to 30%.

[0208] The finally obtained potassium-doped tungsten rod has an average density of 13.82 g / cm 3, the potassium content is 59 ppm, the oxygen content is 10 ppm, and the number of crystal grains per cross-section is 10252 grains / mm 2 , and the average grain size is 28.6 nm.

[0209] The potassium-doped tungsten rods of this comparative example are processed into tungsten wires of different specifications from 0.3 mm to 0.6 mm. The statistical yield is 63% - 70%, 54.8% ≤ qualified rate ≤ 72.5%, 985 N / mm 2 ≤ tensile strength ≤ 1780 N / mm 2 ; 985°C ≤ high-temperature recrystallization temperature ≤ 1050°C, 4.9 mm ≤ high-temperature sag value of 0.39 mm specification ≤ 5.5 mm, length-width ratio ≤ 12. When bent 90 degrees at room temperature and then straightened, cracking occurs. When winding a 4*19*7 structure, the service life of the finished tungsten wire rope has no obvious difference from that of similar products in the market.

[0210] Comparative Example 12

[0211] The manufacturing method of the potassium-doped tungsten rod for a highly flexible tungsten wire rope is basically the same as that of Example 1, and the only difference is that the effective reduction time in step (4) is 5.5 h.

[0212] The finally obtained potassium-doped tungsten rod has an average density of 14.37 g / cm 3 , the potassium content is 60 ppm, the oxygen content is 8 ppm, and the number of crystal grains per cross-section is 9043 grains / mm 2 , and the average grain size is 25.0 nm.

[0213] The potassium-doped tungsten rods of this comparative example are processed into tungsten wires of different specifications from 0.3 mm to 0.6 mm. The statistical yield is 65% - 69%, 55.2% ≤ qualified rate ≤ 75.8%, 985 N / mm 2 ≤ tensile strength ≤ 1780 N / mm 2 ; 1020°C ≤ high-temperature recrystallization temperature ≤ 1200°C, 3.8 mm ≤ high-temperature sag value of 0.39 mm specification ≤ 5.5 mm, length-width ratio ≤ 12. When bent 90 degrees at room temperature and then straightened, cracking occurs. When winding a 4*19*7 structure, the service life of the finished tungsten wire rope has no obvious difference from that of similar products in the market.

[0214] Comparative Example 13

[0215] The manufacturing method of the potassium-doped tungsten rod for a highly flexible tungsten wire rope is basically the same as that of Example 1, and the only difference is that the effective reduction time in step (4) is 8.5 h.

[0216] The finally obtained potassium-doped tungsten rod has an average density of 16.34 g / cm 3 , the potassium content is 60 ppm, the oxygen content is 8 ppm, and the number of crystal grains per cross-section is 8726 grains / mm 2, the average grain size is 22.2 nm.

[0217] The potassium-doped tungsten rods of this comparative example were processed into tungsten wires of different specifications from 0.3 mm to 0.6 mm. The yield rate was statistically 65% - 72%, 52.2% ≤ qualified rate ≤ 76.9%, 920 N / mm 2 ≤ tensile strength ≤ 1680 N / mm 2 ; 980 °C ≤ high-temperature recrystallization temperature ≤ 1250 °C, 4.5 mm ≤ high-temperature sag value of 0.39 mm specification ≤ 5.5 mm, aspect ratio ≤ 12. When bent 90 degrees at room temperature and then straightened, cracking occurred. Wound into a 4*19*7 structure, the service life of the finished tungsten wire rope has no obvious difference from that of similar products in the market.

[0218] Comparative Example 14

[0219] A manufacturing method of potassium-doped tungsten rods for high-flexibility tungsten wire ropes is basically the same as that of Example 1, and the only difference is that in step (8), the potassium-doped tungsten green body is placed in a hydrogen protection furnace at 980 °C and fired for 50 min.

[0220] The finally obtained potassium-doped tungsten rod has an average density of 12.92 g / cm 3 , potassium content is 58 ppm, oxygen content is 10 ppm, the number of crystal grains per cross-section is 7909 grains / mm 2 , the average grain size is 22.0 nm.

[0221] The potassium-doped tungsten rods of this comparative example were processed into tungsten wires of different specifications from 0.3 mm to 0.6 mm. The yield rate was statistically 68% - 71%, 54.1% ≤ qualified rate ≤ 78.9%, 965 N / mm 2 ≤ tensile strength ≤ 1580 N / mm 2 ; 1080 °C ≤ high-temperature recrystallization temperature ≤ 1350 °C, 3.8 mm ≤ high-temperature sag value of 0.39 mm specification ≤ 5.5 mm, aspect ratio ≤ 12. When bent 90 degrees at room temperature and then straightened, cracking occurred. Wound into a 4*19*7 structure, the service life of the finished tungsten wire rope has no obvious difference from that of similar products in the market.

[0222] Comparative Example 15

[0223] A manufacturing method of potassium-doped tungsten rods for high-flexibility tungsten wire ropes is basically the same as that of Example 1, and the only difference is that in step (8), the potassium-doped tungsten green body is placed in a hydrogen protection furnace at 1150 °C and fired for 50 min.

[0224] The finally obtained potassium-doped tungsten rod has an average density of 16.44 g / cm 3 , potassium content is 61 ppm, oxygen content is 9 ppm, the number of crystal grains per cross-section is 10928 grains / mm 2 , the average grain size is 21.6 nm.

[0225] The potassium-doped tungsten rods of this comparative example were processed into tungsten wires of different specifications from 0.3 mm to 0.6 mm. The finished product rate was statistically 64% - 72%, 52.1% ≤ qualified rate ≤ 72.9%, 965 N / mm 2 ≤ tensile strength ≤ 1280 N / mm 2 ; 980 °C ≤ high-temperature recrystallization temperature ≤ 1050 °C, 4.2 mm ≤ high-temperature sag value of 0.39 mm specification ≤ 5.9 mm, aspect ratio ≤ 12. When bent 90 degrees at room temperature and then straightened, cracking occurred. Wound into a 4*19*7 structure, the service life of the finished tungsten wire rope has no obvious difference from that of similar products in the market.

[0226] Comparative Example 16

[0227] A manufacturing method of potassium-doped tungsten rods for highly flexible tungsten wire ropes is basically the same as that of Example 1. The only difference is that the step (9) vertical melting pre-sintering + step (10) intermediate frequency sintering are replaced with vertical melting sintering. Under hydrogen protection, the following vertical melting sintering system (current / time) is carried out: heating up (0 A - 2900 A) / 5 min, heating up (2900 A - 3950 A) / 6 min, heating up (3950 A - 4950 A) / 6 min, holding at 4950 A / 21 min;

[0228] The finally obtained potassium-doped tungsten rods, the finally obtained potassium-doped tungsten rods, have an average density of 12.81 g / cm3, a potassium content of 60 ppm, an oxygen content of 8 ppm, 8206 crystal grains per square millimeter of cross section, and an average grain size of 21.5 nm.

[0229] The potassium-doped tungsten rods of this comparative example were processed into tungsten wires of different specifications from 0.3 mm to 0.6 mm. The finished product rate was statistically 62% - 72%, 52.1% ≤ qualified rate ≤ 69.9%, 915 N / mm 2 ≤ tensile strength ≤ 1230 N / mm 2 ; 780 °C ≤ high-temperature recrystallization temperature ≤ 1080 °C, 4.3 mm ≤ high-temperature sag value of 0.39 mm specification ≤ 5.8 mm, aspect ratio ≤ 12. When bent 90 degrees at room temperature and then straightened, cracking occurred. Wound into a 4*19*7 structure, the service life of the finished tungsten wire rope has no obvious difference from that of similar products in the market.

[0230] Comparative Example 17

[0231] The manufacturing method of the potassium-doped tungsten rod for high-flexibility tungsten wire ropes is basically the same as that of Example 1, except that in the said step (9) vertical sintering pre-sintering + step (10) intermediate frequency sintering, intermediate frequency sintering is used instead. The sintering regime of the intermediate frequency sintering is heating, heat preservation, heating, heat preservation, heating, heat preservation, heating, heat preservation, heating, heat preservation, heating, heat preservation; the temperature / time parameters are in sequence: heating (0 - 1350°C) / 430 min, heat preservation at 1350°C / 9 min, heating (1350 - 1600°C) / 150 min, heat preservation at 1600°C / 180 min, heating (1600 - 1850°C) / 361 min, heat preservation at 1850°C / 180 min, heating (1850 - 2050°C) / 180 min, heat preservation at 2050°C / 180 min, heating (2050 - 2300°C) / 240 min, heat preservation at 2300°C / 120 min, heating (2300 - 2650°C) / 180 min, heat preservation at 2650°C / 300 min.

[0232] The finally obtained potassium-doped tungsten rod has an average density of 16.09 g / cm 3 , the potassium content is 58 ppm, the oxygen content is 10 ppm, and the number of cross-sectional crystals is 9528 / mm 2 , and the average grain size is 21.8 nm.

[0233] The potassium-doped tungsten rods of this comparative example are processed into tungsten wires of different specifications from 0.3 mm to 0.6 mm. The statistical finished product rate is 61% - 70%, 51.0% ≤ qualified rate ≤ 72.5%, 905 N / mm 2 ≤ tensile strength ≤ 1080 N / mm 2 ; 980°C ≤ high-temperature recrystallization temperature ≤ 1050°C, 4.2 mm ≤ high-temperature sag value of 0.39 mm specification ≤ 6.0 mm, aspect ratio ≤ 12. When bent 90 degrees at room temperature and then straightened, cracking occurs. When winding a 4*19*7 structure, the service life of the tungsten wire rope finished product has no obvious difference from that of the same type of products in the market.

[0234] It can be seen from Example 1 and Comparative Examples 16 - 17 that in the present invention, vertical sintering pre-sintering + intermediate frequency sintering is adopted. According to the formation mechanism of potassium bubbles, the number of cross-sectional grains of tungsten bars increases and the local growth of grains is avoided, so as to achieve the purpose of small potassium bubble pore size, large density, many grain boundaries, long potassium bubble columns and uniform distribution. The aspect ratio of potassium bubbles is large and the high-temperature sag resistance performance is good.

[0235] In summary, from Examples 1 and Comparative Examples 1 to 17, it can be seen that the present invention starts from multiple factors, synergistically restricts and balances the relationship between the density and crystallization of potassium-doped tungsten rods, in order to obtain potassium-doped tungsten rods with high density and micron crystal level, so that the tungsten wires made of such tungsten rods have high-temperature creep resistance, high strength, relatively high recrystallization temperature, and stable toughness, effectively improving processing problems such as low finished product rate and low yield of tungsten wires. Further, the tungsten wires obtain excellent high-temperature strength, high-temperature anti-sag performance and anti-deformation performance, and reduce the processing costs of rod and wire materials, saving energy and reducing consumption.

[0236] In Example 2, a functional agent was introduced. Compared with Example 1 where no functional agent was added, the performance of the potassium-doped tungsten rods was significantly improved. This is mainly because the functional agent enhanced the uniform dispersion of each component in the dopant solution on the surface of tungsten bronze, promoted the effective expansion between the montmorillonite layers, increased the active sites, refined the grains, optimized the distribution of doping elements, improved the sintering behavior, increased the reduction efficiency, and enhanced the stability of the material in high-temperature and chemically active environments. As a result, the final product has a higher density, a more uniform microstructure and more excellent mechanical properties. The combined action of these comprehensive effects improves the finished product rate, qualification rate and service life of the tungsten wire rope, giving it a competitive advantage in the market.

[0237] In Example 2 of the present invention, the bentonite used as the functional agent can bring better effects compared with the kaolin in Example 3 and the montmorillonite in Example 4. This may be due to the unique physical and chemical properties of bentonite. Bentonite has a high cation exchange capacity and a large specific surface area, which enables it to more effectively promote the activation of the material surface during the impregnation treatment and enhance the interaction with other components in the solution. In addition, the layered structure of bentonite may be more conducive to the formation of a hierarchical pore structure during hydrothermal treatment and calcination, thereby increasing the dispersion and accessibility of the active components in the dopant solution, and improving the doping efficiency and uniformity. The combined action of these characteristics makes the doped tungsten bars show more excellent results in terms of microstructure and macroscopic properties, such as higher density, finer grain size and more optimized physical properties. Therefore, the use of bentonite in the preparation of the functional agent provides a key boost to improving the overall quality of the doped tungsten bars.

[0238] In multiple embodiments of the present invention, the selection of the functional agent in the dopant solution has a significant impact on the performance of the final potassium-doped tungsten bar. In particular, cobalt chloride used in Example 2 exhibits more excellent performance compared to nickel nitrate in Example 5, zinc nitrate in Example 6, and manganese sulfate in Example 7. This difference may stem from the unique catalytic activity of cobalt chloride, which promotes more efficient reaction kinetics during the doping process, contributing to the formation of a more uniform doping distribution. In addition, cobalt chloride may promote the formation of stable complexes, improve the control of grain growth during sintering, optimize the microstructure, thereby enhancing the mechanical properties and high-temperature stability of the material. These combined effects enable the doped tungsten bar to achieve a better balance in key parameters such as density, potassium content, oxygen content, and grain size, ultimately leading to an increase in the yield rate, qualification rate, tensile strength, and high-temperature performance of the doped tungsten bar, meeting the stringent requirements of the highly flexible tungsten wire rope for materials.

[0239] The above embodiments are only the preferred embodiments of the present invention. Any simple modification, modification, and alternative change made to the above embodiments based on the technical essence of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. A manufacturing method of a potassium-doped tungsten rod for a highly flexible tungsten wire rope, characterized in that, The method is as follows: (1) Material selection Mix ammonium metatungstate with spherical ammonium paratungstate, and use the obtained mixture as the raw material; (2) Pre-reduction Reduce the raw material in step (1) by using a four-zone temperature reduction furnace to obtain ammonium tungsten bronze with cracks on the surface; (3) Vacuum spray doping It is divided into the following four stages: The first stage: Place an appropriate amount of ammonium tungsten bronze obtained in step (2) in a vacuum doping pot, and evacuate to ≤500 pa; The second stage: Dissolve potassium hydroxide, silicic acid, and aluminum nitrate solids in water at 50 - 70 °C completely, then add dilute nitric acid, and continue to stir the above solution to prepare a doping agent solution. Heat the temperature of the doping agent solution to 40 - 50 °C, and then slowly spray it into the vacuum doping pot from the atomization holes. The total amount does not exceed 1 / 3 of the rated addition amount. Open the steam input valve by 1 / 3, and control the steam pressure to 0.1 - 0.2 Mpa. And at this time, it is necessary to keep the materials in the pot turning, and use steam to heat the pot body to keep the temperature of the materials in the furnace at 55 - 85 °C; The third stage: Increase the turning frequency of the pot body, atomize and spray the remaining doping agent solution within 30 - 50 minutes, keep the temperature in the furnace at 85 - 95 °C, open the steam input valve by 2 / 3, and control the steam pressure at 0.1 - 0.2 Mpa; The fourth stage: After finishing the atomization spraying of all doping agents, fully open the steam input valve, control the steam pressure at 0.2 - 0.3 Mpa, raise the temperature in the furnace to 100 - 120 °C, and continuously dry for 3.5 hours to completely evaporate the moisture. When the vacuum degree in the vacuum doping pot remains at 400 - 500 Mpa, turn off the steam heating, perform water cooling until the temperature in the furnace drops to 50 - 55 °C, open the discharge valve and pass through a 20 - 100 mesh sieve to obtain potassium-doped ammonium tungsten bronze; (4) Reduction Reduce the potassium-doped ammonium tungsten bronze obtained in step (3) once in a hydrogen atmosphere to obtain potassium-doped tungsten powder with an average particle size of 3.0 μm - 3.2 μm; In the as-produced particle size distribution of the potassium-doped tungsten powder, the particle size D10 is 3.1 μm - 3.6 μm, the particle size D50 is 8.0 μm - 15 μm, and the particle size D90 is 25 μm - 32 μm; In the ground particle size distribution of the potassium-doped tungsten powder, the particle size D10 is 1.5 μm - 2.1 μm, the particle size D50 is 3.4 μm - 4.1 μm, and the particle size D90 is 6.5 μm - 8.2 μm; (5) Batch pickling Wash the potassium-doped tungsten powder obtained in step (4) successively with 4 mol / L dilute hydrochloric acid and 2 mL / L dilute hydrofluoric acid to remove ineffective potassium and other impurities in the potassium-doped tungsten powder. Then use water at 50 °C - 65 °C to remove the remaining dilute hydrochloric acid and dilute hydrofluoric acid. Finally, dry the tungsten mud in a vacuum box, re-crush the dried tungsten mud, and pass through a sieve to obtain pickled potassium-doped tungsten powder; (6) Mixing Put the pickled potassium-doped tungsten powder obtained in step (5) into a high-speed mixer, mix it for 60 - 120 min under the protection of nitrogen, unload and sieve through a 150 - 200 mesh sieve when cooled to 40 - 50 °C to obtain potassium-doped compound powder; (7) Hard film cold isostatic pressing forming The potassium-doped compound powder obtained in step (6) is filled into a hard rubber mold sleeve with a single weight of 3000 g / root to 4000 g / root, a length of 800 mm, a diameter of 25.5 mm to 27 mm, and a wall thickness of 1.8 mm to 2.2 mm, vibrated and compacted, sealed and fastened, placed in a cold isostatic press, and a potassium-doped tungsten green body is obtained using a pressing pressure of 140 Mpa to 170 Mpa; (8) Low-temperature impurity removal The potassium-doped tungsten green body obtained in step (7) is placed in a hydrogen protection furnace at 1000 °C to 1100 °C and fired for 40 min to 60 min to obtain a potassium-doped tungsten blank with improved strength; (9) Plumbicon pre-sintering Place the potassium-doped tungsten blank obtained in step (8) in a vertical furnace, and under the protection of hydrogen, sinter it by electrification to volatilize more than 95% of the impurities, reaching a density of 15.5 g / cm 3 ~16.5 g / cm 3 , and the initial crystal size obtained on the cross-section is 1.5 nm to 5 nm; The electric sintering system is in sequence of heating up, heating up, heating up, heat preservation; The current / time parameters are in sequence of: heating up from 0 A to 2800 A / 5 min, heating up from 2800 A to 3850 A / 6 min, heating up from 3850 A to 4820 A / 6 min, heat preservation at 4820 A to 4820 A / 21 min; the hydrogen flow rate is 1.8 m³ / h to 2.2 m³ / h; (10) Medium-frequency sintering The incompletely dense potassium-doped tungsten bar obtained in step (9) is placed in a medium-frequency furnace, and the tungsten bars are placed vertically in a stacked firing manner. Double-inlet hydrogen from the furnace bottom and the furnace top is used for sintering under hydrogen protection, and an infrared temperature measurement + PLC temperature control system is used to automatically control the sintering process; the sintering system is in sequence of heating up, heat preservation, heating up, heat preservation, heating up, heat preservation, heating up, heat preservation, heating up, heat preservation, heating up, heat preservation; the temperature / time parameters are in sequence of: heating up (0 to 1250 °C) / 430 min, heat preservation: 1250 °C / 90 min, heating up (1250 to 1500 °C) / 150 min, heat preservation 1500 °C / 120 min, heating up (1500 to 1800 °C) / 361 min, heat preservation 1800 °C / 150 min, heating up (1800 to 1900 °C) / 180 min, heat preservation 1900 °C / 150 min, heating up (1900 to 2000 °C) / 240 min, heat preservation 2000 °C / 120 min, heating up (2000 to 2050 °C) / 180 min, heat preservation 2050 °C / 300 min; In the second stage of the vacuum spray doping in step (3), the content of each substance is 2 to 3 parts by weight of potassium hydroxide, 4.5 to 5.5 parts by weight of silicic acid, 1.8 to 3 parts by weight of aluminum nitrate solid, and 0.1 to 0.3 parts by weight of a functional agent are put into 50 to 70 L of water at 50 to 70 °C and completely dissolved, and then 0.5 to 2 L of dilute nitric acid is added; The preparation method of the functional agent is as follows, by weight: S1. Mix 25 - 35 parts of ZSM-5 molecular sieve with 35 - 45 parts of bentonite. Subsequently, add the mixture to 1400 - 1600 parts of 80 - 90wt% phosphoric acid solution for impregnation treatment for 0.5 - 2 hours to promote the activation of the material surface. After the impregnation process, remove the excess solution through filtration and washing with water, and then carry out drying treatment. Add the dried powder to 1700 - 1900 parts of 60 - 80wt% ethanol aqueous solution for mixing, and then add 5 - 7 parts of 1-octylpyridinium bromide and 8 - 12 parts of calcium disodium EDTA for treatment; After the treatment, obtain the pretreated product through filtration, washing, and drying; S2. Disperse the pretreated product obtained in step 1 in 600 - 800 parts of water, then add 25 - 35 parts of tetraallyl silicate, 55 - 65 parts of diethylenetriamine, and 2 - 4 parts of cobalt chloride to form a homogeneous precursor solution. Treat it at 90 - 98°C and 0.2 - 0.4 MPa for 1 - 3 hours, then through filtration, washing with water, and drying, and then carry out calcination treatment at 300 - 500°C in a nitrogen atmosphere for 2 - 5 hours to obtain the post-treated product; S3. Dissolve 35 - 45 parts of poly-1,2-propanediol and 25 - 35 parts of methyl acetoacetate in 600 - 800 parts of water to form a homogeneous solution. Add 1 - 3 parts of 70 - 85wt% sulfuric acid, under nitrogen protection, control the temperature at 80 - 95°C, and the treatment time is 3 - 10 hours. Collect the liquid in the reactor to obtain the promoter; S4. Mix 30 - 50 parts of the post-treated product obtained in step S2 with 140 - 160 parts of the promoter obtained in step S3, adjust the pH value to 9 - 10.5 with 10 - 18wt% ammonia water, treat for 1 - 3 hours, and then adjust the pH value to 8 - 9 through ammonia evaporation treatment to obtain the functional agent.

2. The manufacturing method of the potassium-doped tungsten rod for the highly flexible tungsten wire rope according to claim 1, characterized in that, In the material selection of step (1), ammonium metatungstate and spherical ammonium tungstate are mixed at a weight ratio of 4:1 - 1.

5.

3. The manufacturing method of the potassium-doped tungsten rod for high-flexibility tungsten wire ropes according to claim 1, characterized in that, In the pre-reduction of step (2), there are cracks in ammonium tungsten bronze, where the cracks account for more than 75% of the total surface area of ammonium tungsten bronze.

4. The manufacturing method of the potassium-doped tungsten rod for high-flexibility tungsten wire ropes as described in claim 1, characterized in that, In the pre-reduction of step (2), the temperatures of the four-zone temperature zone are 300°C - 330°C, 390°C - 410°C, 410°C - 430°C, 430°C - 450°C respectively, the hydrogen flow rate is 0.3 m³ / h - 0.4 m³ / h, the pre-reduction loading amount is 720 g - 800 g, pass through a 20 - 100 mesh sieve, and the pushing speed is 10 - 20 min.

5. The manufacturing method of the potassium-doped tungsten rod for the highly flexible tungsten wire rope according to claim 1, characterized in that, In the vacuum spray doping of step (3), low-power vacuum pumping is used in the initial stages of the second, third, and fourth stages, and medium-high power vacuum pumping is used in the middle and late stages of the fourth stage. Among them, the low power is 25% - 35% of the output power of the vacuum pumping equipment, and the medium-high power is 70% - 85% of the output power of the vacuum pumping equipment.

6. The manufacturing method of the potassium-doped tungsten rod for high-flexibility tungsten wire ropes as described in claim 1, characterized in that, In the reduction in step (4), the temperatures of the five-zone temperature zones for reduction are 660°C to 680°C, 710°C to 740°C, 790°C to 820°C, 820°C to 840°C, and 840°C to 870°C respectively, the hydrogen flow rate is 4 m³ / h to 7 m³ / h, the loading amount is 350 g to 550 g, and the effective reduction time is 6 h to 8 h.

7. The manufacturing method of the potassium-doped tungsten rod for high-flexibility tungsten wire ropes according to claim 1, characterized in that, In step (5) of batch pickling, it is sieved through a 150- to 170-mesh sieve to obtain pickled potassium-doped tungsten powder, and the effective potassium content in the pickled potassium-doped tungsten powder is 65 ppm to 80 ppm.

8. A potassium-doped tungsten rod for a highly flexible tungsten wire rope, characterized in that, It is manufactured by using the manufacturing method described in any one of claims 1 to 7.

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