阅读说明：本技术 自给能中子探测器用高性能钒丝的制备方法 (Preparation method of high-performance vanadium wire for self-powered neutron detector ) 是由 王焱辉 刘奇 吕学伟 薄新维 王小宇 韩校宇 姚志远 何浩然 陈喜 刘晓芸 于 2021-09-16 设计创作，主要内容包括：本发明公开了一种自给能中子探测器用高性能钒丝的制备方法,所述方法是,钒粉预处理→冷等静压成型→真空烧结→真空垂熔→电子束悬浮区域熔炼→旋锻→丝材拉拔→连续电解抛光→退火处理,采用该方法得到的钒丝其纯度V≥99.9％,B、Cd、Cr、Cu杂质元素含量≤30ppm,成品钒丝丝径为1.00mm～1.50mm,精度达到±0.005mm,表面粗糙度≤Ra1.6μm,抗拉强度≥400MPa,延伸率≥10％,米电阻均匀性±1.5％,其精度高、力学性能和表面质量的稳定性较好,能够满足核电工程自给能中子探测器发射体材料的使用性能要求。(The invention discloses a preparation method of a high-performance vanadium wire for a self-powered neutron detector, which comprises the steps of vanadium powder pretreatment → cold isostatic pressing → vacuum sintering → vacuum vertical melting → electronic beam suspension area melting → rotary swaging → wire drawing → continuous electrolytic polishing → annealing treatment, wherein the purity V of the vanadium wire obtained by the method is more than or equal to 99.9%, the content of impurity elements such as B, Cd, Cr and Cu is less than or equal to 30ppm, the diameter of the finished vanadium wire is 1.00-1.50 mm, the precision reaches +/-0.005 mm, the surface roughness is less than or equal to Ra1.6 mu m, the tensile strength is more than or equal to 400MPa, the elongation is more than or equal to 10%, the meter resistance uniformity is +/-1.5%, the precision is high, the mechanical property and the stability of the surface quality are good, and the use performance requirements of a self-powered neutron detector emitter material in nuclear power engineering can be met.)

1. A preparation method of a high-performance vanadium wire for a self-powered neutron detector is characterized by comprising the following steps:

1) vanadium powder pretreatment:

adding high-purity vanadium powder into 20-30 wt% nitric acid solution, and uniformly stirring untilThe slurry is washed by acid and then is washed by deionized water until the slurry is neutral and the vacuum degree is 10^-3Pa, drying at the temperature of 50-70 ℃ for 12-18 h to obtain pretreated vanadium powder;

2) cold isostatic pressing:

cold isostatic pressing the pretreated vanadium powder obtained in the step 1), keeping the pressure of the pretreated vanadium powder at 200-280 MPa for 60-120 s, and taking out the pretreated vanadium powder to obtain a metal vanadium rod;

3) and (3) vacuum sintering:

the metal vanadium rod obtained in the step 2) is sintered in vacuum, and the vacuum degree is more than or equal to 10^-4Pa；

4) Vacuum melting:

the vacuum sintered metal vanadium rod is melted in vacuum with vacuum degree not less than 10^-4Pa；

5) Electron beam levitation zone melting:

vacuumizing the metal vanadium rod subjected to vacuum vertical melting to be more than or equal to 10^-4Pa, gradually adding emission current to 300-400A, moving at the speed of 1.8-2.4 mm/min, and rotating at the speed of 1-3 r/min to obtain a vanadium rod;

6) rotary swaging:

coating organic silicon lubricating coating on the surface of the vanadium rod obtained in the step 5), wherein the single-pass deformation processing amount is 10-15%, the heating temperature is 1000-1100 ℃, the heating time is 3-7 min, and the vanadium metal thin rod is obtained after rotary swaging;

(7) drawing:

carrying out surface gas phase treatment and cold drawing on the vanadium metal thin rod, wherein the single-pass deformation processing amount of the cold drawing is 5-15%, carrying out acid washing and alkali washing on the vanadium wire, and then carrying out vacuum intermediate annealing treatment on the vanadium wire to obtain the vanadium wire, wherein the wire diameter is (1.00-1.50) +/-0.005 mm;

(8) continuous electrolytic polishing:

electrolytic current is 5A-10A, NaOH solution with alkali liquor concentration of 5-10 wt% is used, vanadium wire is continuously subjected to electrolytic polishing, and wire collecting speed is 3-5 m/min;

(9) annealing treatment:

the vanadium wire after continuous electrolytic polishing is kept at the temperature of 850-950 ℃ for 15-25 min, and the vacuum degree is more than or equal to 10^-4And (4) carrying out vacuum annealing under the Pa condition, and then cooling along with the furnace.

2. The method of claim 1, wherein: the weight percentage content of the high-purity vanadium powder in the step 1) is more than or equal to 99.95%, the Fisher particle size is 10-50 mu m, and the particle size is normally distributed.

3. The method of claim 1, wherein: the diameter of the vanadium rod obtained in the step 2) is phi 18 mm-phi 20 mm.

4. The method of claim 1, wherein: the sintering system in the step 3) is as follows: heating up at 10 deg.C/min, keeping the temperature at 400-500 deg.C for 30-60 min, keeping the temperature at 1000-1100 deg.C for 60-90 min, keeping the temperature at 1500-1600 deg.C for 120-150 min, heating up at 7-10 deg.C/min, and cooling with the furnace.

5. The method of claim 1, wherein: and 4) the vertical melting system is that the temperature is maintained for 3-5 min at 400A, 3-5 min at 800A, 20-30 min at 1200A, 3-5 min at 1600A, 3-5 min at 2000A, 20-30 min at 2400A, the temperature is increased at 200A/min and the temperature is decreased at 500A/min.

6. The method of claim 1, wherein: and 5) the diameter of the vanadium rod is phi 13 mm-phi 16mm, and V is more than or equal to 99.9%.

7. The method of claim 1, wherein: and 6) the diameter of the vanadium metal thin rod is phi 4 mm-phi 6 mm.

8. The method of claim 1, wherein: the temperature of the surface gas phase treatment in the step 7) is 400-600 ℃, and the time is 20-30 min.

9. The method of claim 1, wherein: and 7) adopting lubricating oil and chlorinated paraffin as the lubricant during drawing, wherein the lubricating oil: the weight ratio of the chlorinated paraffin is 2: 1.

10. The method of claim 1, wherein: step 7), the vacuum intermediate annealing temperature is 850-1050 ℃, the heat preservation time is 20-30 min, and the vacuum degree is more than or equal to 10^-4Pa。

Technical Field

The invention belongs to the field of metal material preparation, and particularly relates to a preparation method of a high-performance vanadium wire for a self-powered neutron detector.

Background

The high-performance vanadium wire is used as a key material of a self-powered neutron detector emitter in nuclear power engineering, and the material purity, the wire diameter consistency, the mechanical property and the surface quality stability of the high-performance vanadium wire directly influence the sensitivity, the measurement precision, the service life, the neutron flux measurement and other key properties of the self-powered neutron detector. The high-performance vanadium wire is required to have the purity V of more than or equal to 99.9 percent, the content of B, Cd, Cr and Cu radiation-proof impurity elements of less than or equal to 30ppm, the deviation of the nominal diameter of the vanadium wire does not exceed +/-0.01 mm, the surface roughness is not more than Ra1.6 mu m, the tensile strength is more than or equal to 400MPa, the elongation is more than or equal to 7 percent, and the meter resistance uniformity is +/-1.5 percent. Because the metal vanadium belongs to a body-centered cubic structure, the plastic-brittle transition phenomenon exists in the deformation processing process, and the high-temperature processing is easy to oxidize and absorb gas to show brittleness, so that the high-temperature deformation processing of the vanadium wire becomes extremely difficult, the surface quality of the vanadium wire is easy to damage in the cold processing process, and the consistency and the stability of the high-performance vanadium wire are difficult to ensure.

At present, the domestic self-powered neutron detector high-performance vanadium wire still depends on import from abroad, the domestic prepared vanadium wire has the problems of low material purity, difficulty in controlling wire diameter precision, low surface quality stability, poor product consistency and the like, the high-performance vanadium wire cannot be obtained by adopting the prior art, the performance difference still exists between the high-performance vanadium wire and the domestic imported vanadium wire, and the technical requirement of the self-powered neutron detector emitter is difficult to meet.

Disclosure of Invention

The invention aims to provide a preparation method of a high-performance vanadium wire for a self-powered neutron detector, the vanadium wire obtained by the method has the purity V of more than or equal to 99.9 percent, the impurity element content of B, Cd, Cr and Cu of less than or equal to 30ppm, the diameter of the finished vanadium wire is 1.00-1.50 mm, the precision reaches +/-0.005 mm, the surface roughness of less than or equal to Ra1.6 mu m, the tensile strength of more than or equal to 400MPa, the elongation of more than or equal to 10 percent, the meter resistance uniformity of +/-1.5 percent, the precision is high, the mechanical property and the surface quality stability are good, and the use performance requirements of the self-powered neutron detector emitter material in nuclear power engineering can be met.

The technical scheme of the invention is as follows: vanadium powder pretreatment → cold isostatic pressing → vacuum sintering → vacuum fusion → electronic beam suspension area melting → rotary swaging → wire drawing → continuous electrolytic polishing → annealing treatment, which comprises the following steps:

(1) vanadium powder pretreatment: adopting high-purity vanadium powder with the purity V of more than or equal to 99.95 percent, the Fisher particle size of 10-50 mu m and the particle size of normal distribution, and preparing HNO with the concentration of 20-30 wt percent by using concentrated nitric acid and deionized water₃Aqueous solution, adding vanadium powder into HNO₃And (3) uniformly stirring the mixture into a slurry state in the aqueous solution, adding deionized water after acid washing treatment, repeatedly stirring and cleaning, and stopping adding the deionized water when the pH test paper is used for testing to be neutral. After the cleaning is finishedDrying in a vacuum drying oven at 50-70 deg.C for 12-18 hr and under vacuum degree of 10^-3Pa, until the vanadium powder is completely dried, obtaining pretreated vanadium powder;

(2) cold isostatic pressing: pressing and molding the pretreated vanadium powder by using a cold isostatic press, filling the vanadium powder into a stainless steel fixed round bar-shaped rubber die sleeve, sealing and putting into the cold isostatic press, pressing at the pressure of 200-280 MPa for 60-120 s, and taking off the rubber die sleeve after cold isostatic pressing, wherein the diameter of the vanadium rod is phi 18-phi 20 mm. The vanadium powder is pressed by cold isostatic pressing, the forming pressure of the vanadium powder is uniform, and the forming capability of the vanadium powder is improved;

(3) and (3) vacuum sintering: putting the pressed and formed metal vanadium rod into a vacuum intermediate frequency sintering furnace for sintering, wherein the vacuum degree is more than or equal to 10^-4Pa, the sintering system is as follows: heating up at a speed of 10 ℃/min, keeping the temperature at 400-500 ℃ for 30-60 min, keeping the temperature at 1000-1100 ℃ for 60-90 min, keeping the temperature at 1500-1600 ℃ for 120-150 min, heating up at a speed of 7-10 ℃/min, and cooling along with the furnace;

(4) vacuum melting: putting the sintered metal vanadium rod into a vacuum vertical melting furnace for vertical melting, wherein the vacuum degree is more than or equal to 10^-4Pa, the vertical melting system is that the temperature is maintained for 3-5 min at 400A, 3-5 min at 800A, 20-30 min at 1200A, 3-5 min at 1600A, 3-5 min at 2000A, 20-30 min at 2400A, the temperature is increased at 200A/min and the temperature is decreased at 500A/min;

(5) electron beam levitation zone melting: a 50KW electron beam area smelting furnace is adopted, a vanadium rod which is subjected to vacuum vertical smelting is clamped in the furnace through an inlet valve, and the furnace is vacuumized to more than or equal to 10 DEG^-4And Pa, moving the electron gun to a place where the vanadium rod is close to the smelting start below, gradually adding emission current to 300-400A, gradually adding the emission current to the place where the vanadium rod starts to melt, wherein the moving speed of the annular electron gun is 1.8-2.4 mm/min, the rotating speed is 1-3 r/min, melting the vanadium rod in an electron beam area, keeping the melting area between two sections of samples by means of the balance of surface tension and gravity, and realizing directional solidification along with the movement of the electron gun. The impurity elements in the vanadium rod can be effectively removed by electron beam suspension zone melting, so that the content of B, Cd, Cr and Cu is less than or equal to 30ppm, the diameter of the vanadium rod is phi 13 mm-phi 16mm, and the purity is more than 99.9%;

(6) rotary swaging: and (3) adopting rotary swaging machine equipment to carry out rotary swaging on the smelted vanadium rod, wherein the single-pass deformation processing amount is 10-15%, the heating temperature is 1000-1100 ℃, the heating time is 3-7 min, a layer of high-temperature-resistant and oxidation-resistant organic silicon lubricating coating is coated on the surface of the vanadium rod before heating, oxidation air suction during heating of the vanadium rod is avoided, and the vanadium metal thin rod with the diameter of phi 4-phi 6mm is obtained after rotary swaging. The vanadium rod is processed by rotary swaging, crystal grains are refined, and the uniformity of a crystal grain structure is improved.

(7) Drawing: the rotary-forged vanadium metal thin rod adopts the surface gas phase treatment and cold drawing deformation processing modes. The surface gas phase treatment temperature is 400-600 ℃, the treatment time is 20-30 min, wire drawing is carried out after the treatment is finished, the single-pass deformation processing amount of drawing is 5-15%, the lubricant uses a mixture of lubricating oil (wire drawing lubricating oil) and chlorinated paraffin 2:1 (weight ratio), a diamond wire drawing die is adopted as the wire drawing die, after the drawing deformation processing, intermediate annealing treatment is carried out on the vanadium wire to eliminate the deformation processing stress, the vacuum intermediate annealing temperature is 850-1050 ℃, the heat preservation time is 20-30 min, and the vacuum degree is more than or equal to 10^-4And Pa, performing acid washing and alkali washing on the vanadium wire before annealing to remove lubricating oil and chlorinated paraffin attached to the surface of the vanadium wire, wherein the final wire drawing diameter of the vanadium wire is (1.00-1.50) +/-0.005 mm.

(8) Continuous electrolytic polishing: adopting continuous electrolytic polishing technology, wherein the electrolytic current is 5-10A, the concentration of alkali liquor is 5-10 wt% of NaOH solution, and the filament collecting speed is 3-5 m/min. And the vanadium wire surface is smooth and clean through electrolytic polishing, and the surface quality is improved.

(9) Annealing treatment: the vacuum annealing temperature is 850-950 ℃, the heat preservation time is 15-25 min, and the vacuum degree is more than or equal to 10^{- 4}And Pa, cooling along with the furnace.

The invention relates to a preparation method of a high-performance vanadium wire for a self-powered neutron detector, which comprises the steps of adopting vanadium powder pretreatment, cold isostatic pressing, electron beam suspension area smelting, continuous electrolytic polishing and the like, wherein the purity V of the prepared high-performance vanadium wire is more than or equal to 99.9-99.99%, the content of impurity elements such as B, Cd, Cr and Cu is less than or equal to 30ppm, the diameter of the finished vanadium wire is 1.00-1.50 mm, the precision reaches +/-0.005 mm, the surface roughness is less than or equal to Ra1.6 mu m, the tensile strength is more than or equal to 400MPa, the elongation is more than or equal to 10%, the meter resistance uniformity is +/-1.5%, the purity of the vanadium wire is high, the wire diameter precision is high (the wire diameter precision refers to the positive and negative deviation of the wire diameter, generally, the wire diameter is +/-0.01 mm (one wire), the stability of the mechanical property and the surface quality is good, and the self-powered performance requirement of emitter materials of the nuclear power neutron detector in nuclear power engineering can be met.

The invention has the beneficial effects that:

(1) the combined process of vacuum sintering and vacuum vertical melting is adopted, the sintering compactness of the vanadium rod can be effectively improved, the compactness can reach more than 98%, meanwhile, the high vacuum degree avoids the oxidation and air suction of the vanadium rod in the sintering process, and O, N, H interstitial impurity elements are effectively removed.

(2) The method has the advantages of high heating efficiency in a vacuum environment, easy control of temperature gradient, no pollution by crucible materials, effective removal of B, Cd, Cr and Cu impurity elements in the vanadium rod by vacuum evaporation, improvement of purity and density of the vanadium rod, and high purity of the vanadium rod up to more than 99.9%.

(3) The surface gas phase treatment and the cold drawing deformation processing are adopted, the drawing lubrication is improved through the gas phase treatment, cracks and burrs generated in the cold drawing process are avoided, and the surface quality of the vanadium wire is improved. The diamond wire drawing die is adopted to improve the wire diameter precision of the vanadium wire, the wire diameter precision reaches +/-0.005 mm, and the error of the density of the vanadium wire is reduced.

(4) And the surface of the vanadium wire is polished and cleaned by adopting a continuous electrolytic polishing technology, so that the surface of the vanadium wire is smooth and clean, the surface quality stability is improved, and the surface roughness is not more than Ra1.6 mu m.

The vanadium wire prepared by the method has high purity, high wire diameter precision and good stability of mechanical property and surface quality, and can meet the use performance requirement of the emitter material of the self-powered neutron detector in nuclear power engineering.

Drawings

FIG. 1 shows a high-performance vanadium wire for a self-powered neutron detector manufactured by the method of the present invention.

Detailed Description

Example 1:

1500g of vanadium powder was weighed and added to 2500ml of 30 wt% HNO₃Stirring the aqueous solution to slurry, adding deionized water, stirring and cleaning, stopping adding the deionized water when the pH test paper is tested to be neutral, drying the pickled vanadium powder in a vacuum drying oven at 65 ℃, for 12h and with the vacuum degree of 10^-3And Pa, drying to obtain the pretreated vanadium powder.

And pressing and molding the vanadium powder by using a cold isostatic press. After vanadium powder is filled into a rubber die sleeve, the pressure is maintained for 90s in a cold isostatic press at the pressure of 240MPa to obtain a vanadium rod with the diameter phi of 18mm, and then the vanadium rod is placed into a vacuum intermediate frequency sintering furnace for vacuum sintering, wherein the vacuum degree is more than or equal to 10^-4Pa, the sintering system is as follows: heating at 10 deg.C/min, maintaining at 500 deg.C for 30min, maintaining at 1000 deg.C for 60min, maintaining at 1500 deg.C for 120min, and furnace cooling. The sintered metal vanadium rod is subjected to vertical melting in a vacuum vertical melting furnace, wherein the vacuum degree is more than or equal to 10^-4Pa, the vertical melting system is that the current is 400A and the temperature is kept for 3min, the temperature is kept for 3min at 800A, the temperature is kept for 20min at 1200A, the temperature is kept for 3min at 1600A, the temperature is kept for 3min at 2000A, the temperature is kept for 20min at 2400A, the current heating rate is 200A/min, and the cooling rate is 500A/min.

Smelting the vanadium rod after vertical melting in an electron beam suspension area, clamping the vanadium rod after vacuum vertical melting in a furnace through an inlet valve by adopting a 50KW electron beam area smelting furnace, and vacuumizing to be more than or equal to 10^-4And Pa, moving an electron gun to a position where the vanadium rod is close to the melting start below, gradually adding emission current to the emission current 300A, wherein the moving speed of the electron gun is 2.2mm/min, the rotating speed is 3r/min, the vanadium rod is melted in an electron beam area, the melting area is kept between two sections of samples by virtue of the balance of surface tension and gravity, and directional solidification is realized along with the movement of the electron gun. The electron beam suspension zone melting can effectively remove impurity elements in the vanadium rod, and the high-purity vanadium rod with the diameter of phi 15mm is obtained after melting. And then, carrying out rotary swaging on the vanadium rod, carrying out rotary swaging on the smelted vanadium rod by adopting rotary swaging machine equipment, wherein the single-pass deformation processing amount is 10%, the heating temperature is 1100 ℃, the heat preservation time is 5min, a layer of high-temperature-resistant and oxidation-resistant organic silicon lubricating coating is coated on the surface of the vanadium rod before heating, oxidation air suction during heating of the vanadium rod is avoided, and a vanadium metal thin rod with the diameter of 4mm is obtained after rotary swaging.

The rotary-forged vanadium rod is subjected to surface gas phase treatment and cold drawing processing in sequence, wherein the surface gas phase treatment temperature is 450 ℃, the treatment time is 20min, wire drawing is carried out after the treatment, a lubricant uses a mixture of lubricating oil and chlorinated paraffin 2:1, a drawing die adopts a diamond drawing die, the single-pass deformation processing amount of drawing is 8%, the vacuum intermediate annealing heat treatment temperature is 1000 ℃, and the vacuum degree is more than or equal to 10^{- 4}Pa, keeping the temperature for 20min, eliminating the deformation processing stress, ensuring the final wire drawing diameter of the vanadium wire to be 1.00mm +/-0.005 mm, and pickling the vanadium wire before annealing (the concentration is 5 percent of HF and 15 percent of HNO)₃A mixed liquor, wherein HF: HNO₃The volume ratio of (1) to (8) and alkaline washing (3% NaOH solution, the same applies below), removing the lubricating oil and chlorinated paraffin adhered to the surface of the vanadium wire. Continuous electrolytic polishing of vanadium wire is adopted, the electrolytic current is 5A, the concentration of alkali liquor is 7 wt% of NaOH solution, and the wire collecting speed is 5 m/min. And finally, carrying out vacuum annealing on the polished vanadium wire at the vacuum annealing temperature of 850 ℃ for 20min, and cooling along with the furnace to obtain the high-performance vanadium wire for the self-powered neutron detector.

Through test detection, the high-performance vanadium wire obtained by the method has the wire diameter of 1.00mm, the purity of 99.90 percent, the impurity element content of B, Cd, Cr and Cu of less than or equal to 30ppm, the wire diameter precision of +/-0.005 mm, the surface roughness of Ra0.2 mu m, the tensile strength of 462MPa, the elongation of 12.7 percent and the meter resistance uniformity of +/-1.5 percent.

Example 2:

2000g of vanadium powder was weighed and 3500ml of 30 wt% HNO was added to the vanadium powder₃And stirring the aqueous solution to be slurry, adding deionized water, stirring and cleaning, stopping adding the deionized water when the pH test paper is tested to be neutral, and drying the pickled vanadium powder in a vacuum drying oven at the drying temperature of 70 ℃ for 15 hours to obtain the pretreated vanadium powder.

And pressing and molding the vanadium powder by using a cold isostatic press. After vanadium powder is filled into a rubber die sleeve, the pressure is maintained for 60s in a cold isostatic press at the pressure of 280MPa to obtain a vanadium rod with the diameter phi of 20mm, and then the vanadium rod is placed into a vacuum intermediate frequency sintering furnace for vacuum sintering, wherein the vacuum degree is more than or equal to 10^-4Pa, the sintering system is as follows: heating at 10 deg.C/min, maintaining at 500 deg.C for 40min, maintaining at 1000 deg.C for 80min, and maintaining at 1500 deg.CAnd (4) cooling with the furnace for 120 min. The sintered metal vanadium rod is subjected to vertical melting in a vacuum vertical melting furnace, wherein the vacuum degree is more than or equal to 10^-4Pa, the vertical melting system is that the current is 400A and the temperature is kept for 3min, the temperature is kept for 3min at 800A, the temperature is kept for 25min at 1200A, the temperature is kept for 3min at 1600A, the temperature is kept for 3min at 2000A, the temperature is kept for 25min at 2400A, the current heating rate is 200A/min, and the cooling rate is 500A/min.

Smelting the vanadium rod after vertical melting in an electron beam suspension area, clamping the vanadium rod after vacuum vertical melting in a furnace through an inlet valve by adopting a 50KW electron beam area smelting furnace, and vacuumizing to be more than or equal to 10^-4And Pa, moving an electron gun to a position where the vanadium rod is close to the melting start below, gradually adding emission current to the emission current of 350A, wherein the moving speed of the electron gun is 2.0mm/min, the rotating speed is 3r/min, the vanadium rod is melted in an electron beam area, the melting area is kept between two sections of samples by virtue of the balance of surface tension and gravity, and directional solidification is realized along with the movement of the electron gun. The electron beam suspension zone melting can effectively remove impurity elements in the vanadium rod, and the high-purity vanadium rod with the diameter of phi 14mm is obtained after melting. And then, carrying out rotary swaging on the vanadium rod, carrying out rotary swaging on the smelted vanadium rod by adopting rotary swaging machine equipment, wherein the single-pass deformation processing amount is 12%, the heating temperature is 1100 ℃, the heat preservation time is 5min, a layer of high-temperature-resistant and oxidation-resistant organic silicon lubricating coating is coated on the surface of the vanadium rod before heating, oxidation air suction during heating of the vanadium rod is avoided, and a vanadium metal thin rod with the diameter of 5mm is obtained after rotary swaging.

The rotary-forged vanadium rod is subjected to surface gas phase treatment and cold drawing processing in sequence, wherein the surface gas phase treatment temperature is 500 ℃, the treatment time is 25min, wire drawing is carried out after the treatment, a lubricant uses a mixture of lubricating oil and chlorinated paraffin 2:1, a drawing die adopts a diamond drawing die, the single-pass deformation processing amount of drawing is 10%, the vacuum intermediate annealing heat treatment temperature is 980 ℃, the vacuum degree is more than or equal to 10^{- 4}Pa, keeping the temperature for 25min, eliminating deformation processing stress, enabling the final wire drawing diameter of the vanadium wire to be 1.10mm +/-0.005 mm, and carrying out acid washing and alkali washing on the vanadium wire before annealing to remove lubricating oil and chlorinated paraffin adhered to the surface of the vanadium wire. Continuous electrolytic polishing of the vanadium wire is adopted, the electrolytic current is 6A, the concentration of an alkali liquor is 7 wt% of NaOH solution, and the wire collecting speed is 4 m/min. Finally, carrying out vacuum annealing on the polished vanadium wire at the vacuum annealing temperature of 900 ℃ for 20min,and cooling along with the furnace to obtain the high-performance vanadium wire for the self-powered neutron detector.

Through test detection, the high-performance vanadium wire obtained by the method has the wire diameter of 1.10mm, the purity of 99.92 percent, the impurity element content of B, Cd, Cr and Cu of less than or equal to 30ppm, the wire diameter precision of +/-0.005 mm, the surface roughness of Ra0.2 mu m, the tensile strength of 485MPa, the elongation of 11.5 percent and the meter resistance uniformity of +/-1.5 percent.

Example 3:

2500g of vanadium powder was weighed and 4000ml of 30 wt% HNO was added to the vanadium powder₃And stirring the aqueous solution to be slurry, adding deionized water, stirring and cleaning, stopping adding the deionized water when the pH test paper is used for testing to be neutral, and drying the pickled vanadium powder in a vacuum drying oven at the drying temperature of 70 ℃ for 18 hours to obtain the pretreated vanadium powder.

And pressing and molding the vanadium powder by using a cold isostatic press. After vanadium powder is filled into a rubber die sleeve, the pressure is maintained for 120s in a cold isostatic press at the pressure of 220MPa to obtain a vanadium rod with the diameter phi of 20mm, and then the vanadium rod is placed into a vacuum intermediate frequency sintering furnace for vacuum sintering, wherein the vacuum degree is more than or equal to 10^-4Pa, the sintering system is as follows: heating at 10 deg.C/min, maintaining at 500 deg.C for 60min, at 1100 deg.C for 60min, at 1500 deg.C for 150min, and furnace cooling. The sintered metal vanadium rod is subjected to vertical melting in a vacuum vertical melting furnace, wherein the vacuum degree is more than or equal to 10^-4Pa, the vertical melting system is that the current is 400A and the temperature is kept for 4min, the temperature is kept for 4min at 800A, the temperature is kept for 30min at 1200A, the temperature is kept for 4min at 1600A, the temperature is kept for 4min at 2000A, the temperature is kept for 30min at 2400A, the current heating rate is 200A/min, and the cooling rate is 500A/min.

Smelting the vanadium rod after vertical melting in an electron beam suspension area, clamping the vanadium rod after vacuum vertical melting in a furnace through an inlet valve by adopting a 50KW electron beam area smelting furnace, and vacuumizing to be more than or equal to 10^-4And Pa, moving an electron gun to a position where the vanadium rod is close to the melting start below, gradually adding emission current to the emission current 300A, wherein the moving speed of the electron gun is 1.8mm/min, the rotating speed is 2r/min, the vanadium rod is melted in an electron beam area, the melting area is kept between two sections of samples by virtue of the balance of surface tension and gravity, and directional solidification is realized along with the movement of the electron gun. The electron beam suspension zone melting can effectively remove vanadium rodsThe impurity elements are smelted to obtain the high-purity vanadium rod with the diameter of phi 16 mm. And then, carrying out rotary swaging on the vanadium rod, carrying out rotary swaging on the smelted vanadium rod by adopting rotary swaging machine equipment, wherein the single-pass deformation processing amount is 15%, the heating temperature is 1100 ℃, the heat preservation time is 7min, a layer of high-temperature-resistant and oxidation-resistant organic silicon lubricating coating is coated on the surface of the vanadium rod before heating, oxidation air suction during heating of the vanadium rod is avoided, and a vanadium metal thin rod with the diameter of 6mm is obtained after rotary swaging.

The rotary-forged vanadium rod is subjected to surface gas phase treatment and cold drawing processing in sequence, wherein the surface gas phase treatment temperature is 500 ℃, the treatment time is 30min, wire drawing is carried out after the treatment, a lubricant uses a mixture of lubricating oil and chlorinated paraffin 2:1, a drawing die adopts a diamond drawing die, the single-pass deformation processing amount of drawing is 10%, the vacuum intermediate annealing heat treatment temperature is 950 ℃, and the vacuum degree is more than or equal to 10^{- 4}Pa, keeping the temperature for 30min, eliminating the deformation processing stress, ensuring the final wire drawing diameter of the vanadium wire to be 1.50mm +/-0.005 mm, and carrying out acid washing and alkali washing on the vanadium wire before annealing to remove lubricating oil and chlorinated paraffin adhered to the surface of the vanadium wire. Continuous electrolytic polishing of vanadium wire is adopted, electrolytic current is 8A, NaOH solution with 10 percent of alkali liquor concentration by weight is adopted, and wire collecting speed is 3 m/min. And finally, carrying out vacuum annealing on the polished vanadium wire at the vacuum annealing temperature of 900 ℃ for 25min, and cooling along with the furnace to obtain the high-performance vanadium wire for the self-powered neutron detector.

Through test detection, the high-performance vanadium wire obtained by the method has the wire diameter of 1.50mm, the purity of 99.94 percent, the impurity element content of B, Cd, Cr and Cu of less than or equal to 30ppm, the wire diameter precision of +/-0.005 mm, the surface roughness of Ra0.4 mu m, the tensile strength of 563MPa, the elongation of 14.7 percent and the meter resistance uniformity of +/-1.5 percent.

FIG. 1 is a high performance vanadium wire for a self-powered neutron detector obtained using the methods described in examples 1-3.