RU2285739C2 - METHOD OF PRODUCTION OF THIN-WALLED TUBULAR BILLET FROM Nb OR Ta INGOT FOR FORMING DIFFUSION BARRIER IN SUPERCONDUCTORS (VERSIONS) - Google Patents

Abstract

FIELD: metallurgy; production of superconducting wires operating at temperature of liquid helium in magnetic systems of charged-particle accelerators.

SUBSTANCE: proposed method includes homogenizing annealing of ingot within temperature interval of from 1200 to 1350°C and application of protective copper coat on ingot. Then, ingot is heated to temperature of 800-900°C and is subjected to extrusion deformation for obtaining first billet which is subjected to machining followed by application of protective copper coat. First billet is heated at temperature of 800-900°C and is subjected to extrusion deformation for obtaining second billet which is also subjected to machining. Then, the following operations are performed: re-crystallization annealing at temperature of from 950 to 1250°C, cold rolling to preset size of billet and re-crystallization annealing at temperature of from 950 to 1250°C. Billets thus produced possess property for further deformation at total drawing of up to 9·10⁸ for production of superconductors.

EFFECT: enhanced efficiency; avoidance of undesirable diffusion processes.

7 cl, 3 ex

Description

The invention relates to the field of low-temperature electrical engineering and can be used in the manufacture of superconducting wires designed to operate at liquid helium temperature in magnetic systems of charged particle accelerators, thermonuclear fusion units, energy storage devices, medical NMR tomographs, cryoturbogenerators and cryomotors. The invention can also be used for other applications where thin-walled tubes of Nb and Ta and alloys based on Nb and Ta are required, for example, in the chemical industry, aviation, space and reactor engineering.

Diffusion barriers are an integral part of the design of composite superconducting materials based on the NbTi alloy and the intermetallic compound Nb ₃ Sn. Nb and Ta are usually used as barrier materials. Diffusion barriers made of niobium are used in the construction of NbTi superconductors to prevent interaction at the NbTi alloy / copper interface, leading to the formation of brittle intermetallic compounds of the Ti-Cu system, which cause breakage of individual superconducting fibers and wires as a whole and reduce its electrophysical characteristics [1-3]. In the designs of superconductors based on the Nb ₃ Sn intermetallic compound, niobium and tantalum barriers are used to prevent the penetration of tin into copper, which leads to a deterioration in the stabilizing properties of copper [4]. In this case, niobium or tantalum barriers are placed between the tin bronze and the copper matrix. Currently, niobium and tantalum barriers are used in the form of a folded sheet (shell), tape or foil [1-4]. Typically, Nb and Ta barriers are laid in monofilament or multi-fiber assemblies before extrusion of the composite.

The disadvantages of the barrier of a sheet, tape or foil is the need to create an overlap of the edges, next to which, during subsequent redistribution, it is thinned and even torn, as well as the need to provide large gaps between the shell of the sheet, tape or foil and a copper glass when forming a composite billet. The presence of an overlap and the need to provide gaps leads to an asymmetry of the assembly of the composite billet, a change in the fill factor in the superconductor from assembly to assembly, and a decrease in the quality of superconducting wires.

The main feature of the barrier materials in the form of a rolled sheet, tape, foil, used for the manufacture of diffusion barriers in superconductors, is that they must have a set of properties necessary for further joint deformation in a composite containing many other elements. This set of properties includes stringent requirements for grain size and mechanical properties. The barrier material should have a uniform fine grain of 20-60 microns in size, yield strength up to 250 MPa and elongation of 45-60%.

Niobium and tantalum for diffusion barriers must be sufficiently ductile to withstand large deformation without tearing (9 × 10 ⁸ hood) during the subsequent manufacture of superconducting wires from the initial workpiece to the finished wire. Therefore, niobium and tantalum of electron beam melting are used for these purposes. One of the drawbacks of electron beam melting materials is the heterogeneity of the distribution of gas impurities, as a result of which the hardness and deformability for such materials are heterogeneous. Thus, according to our data, in a niobium ingot with an average hardness HB = 56.5 kg / mm ^{2, the} difference in hardness reaches 1.5 times, and during the manufacturing of superconductors, due to the inhomogeneity of the plastic characteristics of the initial niobium, local thinning and even rupture of niobium diffusion occurs the barrier.

Large grains characteristic of the cast structure of pure niobium and tantalum introduce significant features into the technology of their processing by pressure. The primary processing of niobium and tantalum ingots is the destruction of the cast structure by extrusion or forging. Extrusion modes depend on the parameters of the available equipment. As a rule, this “hot” or “warm” treatment is carried out using coatings or shells, since surface gas saturation can seriously reduce the ductility of the material. After the destruction of the cast structure, further pressure treatment is performed by direct or reverse extrusion and rolling.

The highest symmetry of the assembly of the composite billet due to the small gaps between its components can be achieved using tube barriers. They provide high dimensional accuracy of the elements of the composite billet for the manufacture of superconductors, good geometry, stabilization of the fill factor and high quality superconducting wire.

If pipes are used to form a diffusion barrier in superconductors, they must be solid-rolled and have an outer diameter of 4 to 115 mm with a wall thickness of 0.1-3.5 mm, as well as a uniform fine grain with a size of 20-60 microns, yield strength up to 250 MPa and elongation of 45-60%. This combination of dimensional, strength and plastic characteristics in the resulting thin-walled solid-rolled pipe most fully meets the requirements necessary for the manufacture of a barrier layer in composite billets in the production of superconducting wires.

Thin-walled solid-rolled niobium and tanatal pipes currently produced by industry have a maximum size of 27 × 3 mm [5] and 38 × 0.56 mm [6], which does not correspond to the pipe sizes required for the manufacture of most superconductors (70-115 mm) . It is proposed to produce thin-walled pipes of large diameter either by welding from a sheet billet bent on a cylindrical mandrel [6], or by cold rolling a welded billet from cold-rolled strips [5], which is unacceptable for the production of superconductors.

A known method of manufacturing pipes from niobium and tantalum [5], including the operation of applying glass powder to a hot ingot with a diameter of 150-250 mm with the formation of a protective layer of melted glass, pressing (extruding) a rod with a diameter of 80-120 mm at a temperature of 1500-1550 ° C, cutting the bar into billets with a length of 100-150 mm, obtaining a hollow billet (checkers) by drilling, vacuum homogenizing annealing of the billet at a temperature of 1300-1350 ° C for 3-4 hours, pressing a hollow billet (checkers) into a tube stock with a diameter of 30-60 mm at a temperature of 1200 -1300 ° С, rolling of a tube billet at the KhPT mills and at the KhPTR roller mills with the production of pipes, recrystallization annealing of the pipes in vacuum at a temperature of 1280 ° С for 2 hours.

This method of manufacturing pipes from niobium has several disadvantages.

1. Heating of ingots to temperatures of 1500-1550 ° C, which are higher than the temperature of recrystallization, leads to a decrease in the degree of stored deformation and an increase in the temperature of subsequent vacuum recrystallization annealing, which in turn leads to an increase in the average size of the recrystallized grain and a decrease in the plastic characteristics of the material.

2. Vacuum homogenizing annealing at a temperature of 1300-1350 ° C for 3-4 hours is carried out after pressing the bar stock, which also leads to a decrease in the degree of stored deformation and an increase in the temperature of subsequent vacuum recrystallization annealing, which in turn leads to an increase in the average size recrystallized grains and reduced plastic characteristics of the material.

3. The use of glass powders as a protective layer and lubricant for pressing ingots requires special safety measures when applying powder to a hot ingot under production conditions. In addition, the resulting compacts require further deep machining.

4. According to this method, pipes of only small diameter are manufactured (tantalum pipes with a diameter of up to 26.4 mm with a wall thickness of 0.87 mm and niobium pipes with a diameter of up to 27 mm with a wall thickness of 3 mm). The method does not cover the range of pipes required for the production of superconductors from niobium and tantalum (i.e. pipes with a diameter of 4-115 mm with a wall thickness of 0.1-3.5 mm).

5. The method does not make it possible to obtain pipes with the set of properties that is required for workpieces used as diffusion barriers in the manufacture of superconductors.

There is another method of manufacturing pipes from niobium and tantalum [7], according to which, the pressing of pipes from pre-deformed pipe blanks is carried out at a temperature of 1000-600 ° C and below. As lubricant and protection, graphite and copper foil are used on the inner and outer surfaces of the workpiece. As the initial blank for the manufacture of thin-walled pipes, pressed pipes or blanks in the form of cups obtained by deep drawing from a sheet are used. Pipes are made by rolling or drawing through dies in a cold state. In this way, seamless pipes are made with an outer diameter of 0.3 to 28.5 mm and a minimum inner diameter of 0.1 mm with a wall thickness of 0.1 mm.

This method of manufacturing pipes also has several disadvantages.

1. The use of copper foil as a protective layer and lubricant for pressing ingots requires, firstly, the manufacture of foil and, secondly, deep machining of the workpiece due to the large surface relief on the pressed workpieces.

2. In addition, according to this method, pipes of only small diameter are produced (tantalum pipes with a diameter of up to 28.5 mm with a wall thickness of 0.87 mm and niobium pipes with a diameter of up to 27 mm with a wall thickness of 3 mm). The method does not cover the nomenclature of pipes required for the production of superconductors from niobium and tantalum (diameter 4-115 mm, wall thickness 0.1-3.5 mm).

There is also known a method of manufacturing sheets of Nb [8], including the operation of applying glass powder to a hot ingot with a diameter of 120-250 mm with the formation of a protective layer of melted glass, pressing or forging a flat plate (punch) with a section of 40 × 120 mm ² and 60 × 80 mm ² of ingots with a diameter of 120-150 mm at a temperature of 1400-1550 ° C above the recrystallization temperature, dressing and cutting of workpieces, surface machining, etching, recrystallization annealing at a recrystallization temperature of 1200-1300 ° C for 1-2 hours and cold rolling sheet rolling tnyh mills to obtain a sheet thickness of 0.8-1.0 mm in size to 600-800 mm × 1500-2000. The disadvantages of this method include the following.

1. The use of glass powders as a lubricant for pressing ingots, which requires special safety measures when applying powder to a hot ingot under production conditions.

2. Significant deflection and helical turn of the received flaps relative to the axis of deformation, causing the need for dressing before machining the surface.

3. Prolonged and deep machining of the surface of the slider due to the lack of the necessary plane parallelism of the faces after dressing, leading to a significant loss of metal.

4. Uneven development of the cast structure during the pressing of the pimp, leading to the formation of an inhomogeneous grain structure during subsequent recrystallization heat treatment. The size of the recrystallized grain in this case ranges from 10 to 120 microns in one small bag, which is unacceptable for use in the production of superconductors.

An object of the present invention is to obtain thin-walled tube blanks from niobium and tantalum for use as diffusion barriers with a given set of properties, providing the ability to further deformation with a total hood of up to 9 × 10 ⁸ in the manufacture of superconductors and guaranteeing the prevention of unwanted diffusion processes throughout the manufacturing process superconductors.

The solution to this problem is achieved in that, in comparison with the analogue [7], which provides for the homogenizing annealing of an ingot, applying a protective coating of copper and subsequent deformation in the manufacture of a thin-walled tube billet from an Nb or Ta ingot, a method for manufacturing a thin-walled tube billet from an Nb or That for the formation of a diffusion barrier in superconductors (including homogenizing annealing of the ingot, applying a protective coating of copper to the ingot and its deformation), in which the homogenizing tzhig is carried out in the temperature range 1200-1350 ° C, the protective coating of copper is applied by a galvanic method, then the ingot is heated and deformed by extrusion to obtain the first pipe billet, which is subjected to mechanical processing followed by the application of a protective coating of copper by a galvanic method, the first pipe billet is heated and squeezed out to obtain a second pipe billet, which is subjected to mechanical processing, then recrystallization annealing is carried out in the temperature range from 950 to 1250 ° C, cold proc rolling to a predetermined size and recrystallization annealing in the temperature range from 950 to 1250 ° С, while heating before extruding both the ingot and the first tube billet is carried out at a temperature of 800-900 ° С, which is lower than the material recrystallization temperature.

In the particular case of the method, the first tubular billet is obtained by the method of backward extrusion.

In another particular case of the implementation of the method for forming a copper protective layer on the inner surface of the hollow billet, when extruding under the pierce, a copper gasket is laid. Moreover, its thickness should be at least 3 mm.

In another embodiment, the solution of the technical problem is also achieved by the fact that the proposed method of manufacturing a thin-walled tube billet from an ingot of refractory material Nb or Ta for forming a diffusion barrier in superconductors, including homogenizing annealing of the ingot, applying a protective coating of copper to the ingot and its deformation, in which homogenizing annealing is carried out in the temperature range 1200–1350 ° С, a protective coating of copper is applied by a galvanic method, then the ingot is heated and deformed by extrusion to obtain m of the first tube billet, which is subjected to mechanical processing followed by a protective coating of copper by the galvanic method, the first tube billet is heated and extruded to obtain a second tube billet which is subjected to machining, the second tube billet is cut and straightened to obtain a flat billet, then it is carried out cold rolling to obtain a sheet of a given size, which is rolled into a cylindrical billet, and conduct final recrystallization annealing, p and this heating prior to extrusion is carried out at a temperature of 800-900 ° C which is below the recrystallization temperature of the material before cold rolling and the slab is carried out recrystallization annealing, which is the final and recrystallization annealing was carried out in a temperature range from 950 to 1250 ° C.

In the particular case of the implementation of this method, the first tube billet is obtained by the method of backward extrusion.

In another particular case of the implementation of the method for forming a copper protective layer on the inner surface of the first tube billet, when extruding under the pierce, a copper gasket is laid. Moreover, its thickness should be at least 3 mm.

In the proposed method (in both its variants), the ingot is first subjected to vacuum (10 ⁴ -10 ⁵ mm Hg) homogenizing annealing at temperatures above 1200 ° C, but not more than 1350 ° C, as a result of this, partial degassing, leveling of the content gas impurities and, as a consequence, hardness over the cross section of the ingot. The annealing temperature is chosen on the basis that it should provide a sufficiently high diffusion rate of gas impurities so that it is economically feasible, but not lead to grain growth. The diffusion rate of the main gas impurity of oxygen in niobium at a temperature of 1200 ° C is 10 mm / h, which is sufficient to equalize its concentration on the ingot for 8-10 hours. An increase in the temperature of homogenizing annealing leads to an increase in the diffusion rate, however, in pure niobium at temperatures above 1350 ° C, an increase in grain size is observed, which is undesirable for subsequent redistribution.

After homogenizing annealing, a galvanic copper coating with a thickness of 150-200 μm is applied to the surface of the ingot, which provides protection against oxidation during heating and at the same time serves as a lubricating layer during extrusion. The thickness of the copper coating is sufficient to protect against oxidation, however, the proposed protective coating has a thickness much less than currently used coatings in the form of copper foil or glass-based. This makes it possible to reduce the surface relief of the pressed billets that occurs when the more solid components of the composite and large soft copper are deformed together with insufficient backing from the tool side, which requires deep machining of the surfaces of the pressed billets.

In the proposed method, the pressing processes are carried out at a temperature of 800-900 ° C, which is below the recrystallization temperature, which allows to increase the degree of stored deformation and lower the temperature of subsequent vacuum recrystallization annealing, which in turn allows to reduce the average size of the recrystallized grain and increase the plastic characteristics of the material. The recrystallization temperature of pure niobium and tantalum depends on the content of gas impurities and the degree of preliminary deformation. When the content of gas impurities is at the level specified in modern standards for refractory materials of electron beam melting, and with the degrees of deformation commonly used in extruding ingots, it is 1150-1250 ° C for niobium and 900-1000 ° C for tantalum.

Deformation accumulated in the material after low-temperature extrusion allows forming a final thick-walled tube billet (second tube billet) after vacuum recrystallization annealing, which has a uniform fine-grained structure with a grain size of up to 150 μm.

Thin-walled pipes with a diameter of 4-115 mm with a ratio of D _tr / t _st up to 170 (where D _tr is the diameter of the outer tube, t _st is the thickness of the pipe wall) are made from this thick-walled tube billet by cold rolling on tube rolling mills.

The resulting thin-walled solid-rolled pipe (cylindrical shell) of refractory material is characterized by the fact that it has dimensions (diameter 4-115 mm, wall thickness 0.1-3.5 mm), structure (uniform fine grain with a size of 20-60 microns) and properties (yield strength up to 250 MPa with elongation up to 45-60%) required for the formation of high-quality diffusion barriers in the manufacturing process of superconductors. It is these properties that ensure the high ductility of diffusion barriers in the manufacturing process of superconductors.

The formed thick-walled tube billet with a uniform fine-grained structure can be cut along the axis of deformation into two or more parts and straightened, as a result of which we obtain flat rectangular billets, which are rolled into cold in two mutually perpendicular directions on sheet mills to produce sheets of different thicknesses that can be subjected to final vacuum recrystallization annealing to provide structural, strength, and plastic characteristics required for diffusion barriers line providers.

The sheets are rolled up on rollers to obtain a shell, which is subjected to a final vacuum recrystallization annealing to provide the structural, strength and plastic characteristics required for diffusion barriers.

Case Studies

Example 1. Niobium ingots with a diameter of 250 mm and 150 mm and a height of 800 mm were cut into blanks. At the end sections of the billets, hardness was measured at 13 points at each end. The blanks were homogenized in vacuum at a temperature of 1300 ° C for 8 hours and the hardness was again measured. As a result of partial degassing and redistribution of impurities during annealing, there are no zones with increased hardness in the workpieces. Cast billets with a diameter of 250 mm were machined to a diameter of 245 mm, and then a copper layer 150-200 μm thick was deposited on them by galvanic deposition in a sulfuric acid electrolyte at a current density of 1.5-2.5 A / dm ² . After that, the preforms were dried in air, coated with graphite grease and pressed into a bar with a diameter of 150 mm at a temperature of 930 ° C, cut into preforms with a height of 150 mm, turned to a diameter of 148.5 mm, and a galvanic copper coating was applied again. Cast billets with a diameter of 150 mm and a height of 150 mm were machined to a diameter of 148.5 mm. Then, drilling was performed on all the blanks to form an inner centering cylindrical hole with a diameter of 21 mm. After that, a layer of copper with a thickness of 150-200 μm was applied to the workpieces. The preforms were air dried and coated with graphite based grease. After heating in a resistance furnace at a temperature of 800 ° C for 1.5-2 hours, the preforms were stitched on a vertical press with a piercing diameter of 80-84 mm with the application of a central copper strip under the piercing to form a copper protective layer on the inner surface. After trimming the bottom part and machining the outer and inner surfaces, the galvanic copper coating was repeatedly applied to the obtained hollow billets with a size of 148.5 × 83-87 × 250 mm. Then the hollow billets were dried, graphite grease was applied, heated at a temperature of 950 ° C and squeezed out into tube billets of 106.5 × 82-86 × 800 mm in size. After machining, the tube blanks measuring 103.5 × 83.5-87.5 × 780 mm were vacuum annealed at a temperature of 1250 ° C for 2 hours. The average grain size in the tube blanks was 200-250 microns.

For the manufacture of niobium tube barriers with a size of 63 × 61.6 mm, tube billets were rolled at the HPT mill to a size of 92 × 76 mm in one transition, then at the HPTR mill to a finished size of 63 × 61.6 mm in three transitions. Ten tube blanks for the manufacture of tube barriers of dimensions 85.5 × 84.1 mm, 83 × 81.4 mm and 81.5 × 78.5 mm were rolled at the KhTPR mill to a finished size of 5 transitions. The resulting pipes were cut into measured lengths and annealed in vacuum. After annealing, the pipes had a uniform fine grain with a size of 20–40 μm, a yield strength of 130 MPa, and an elongation of 45%.

Pipes were used as a diffusion barrier in the manufacture of NbTi superconductors. The high quality of the barriers, the uniformity of structure and properties, the absence of breaks and local thinning of the barrier surrounding the fiber, made it possible to increase the duration and temperature of heat treatments in the manufacture of wires and raise the critical current density to 2900 A / mm ² .

Example 2. For the manufacture of sheet niobium barriers, tube blanks measuring 103.5 × 83.5-87.5 × 780 mm were cut perpendicular to the axis on a lathe and along on a milling machine with the formation of 4 half-cylinders. Then, the obtained half-cylinders were straightened on a hydraulic press with a force of 2000 ton-force between plane-parallel strikers until a flat rectangular billet with a size of 385 × 10.1 × 146 mm was formed. Rectangular billets were rolled in two mutually perpendicular directions on sheet-type rolling mills of the Duo type into a sheet measuring 250 × 1 × 2283 mm. Sheets were cut into cards 242 × 1 × 420 mm in size. Shells were formed from each card on rollers with diameters of 80 and 40 mm, which, after vacuum annealing, were used as a diffusion barrier in the manufacture of small-scale batches of NbTi superconductors. The grain size after recrystallization annealing of Nb tube and sheet barriers was 40-60 μm.

Example 3. Three tantalum ingots with a diameter of 116-118 mm and a height of 160-180 mm were coated with a galvanic copper layer 150-200 mm thick, heated to a temperature of 700 ° C for 1.5 hours and deposited in a container with a diameter of 125 mm. After machining and re-applying the copper coating, the preforms were stitched with a piercing diameter of 68 mm. Then cut the bottom and again subjected to mechanical processing. A galvanic layer of copper was applied to hollow billets, heated to 850 ° C for 1.5 hours, and squeezed into a pipe billet measuring 80 × 65 × 800 mm. After machining the billets with a size of 78 × 67 × 780 mm, they were subjected to vacuum annealing at a temperature of 1050 ° C for 1 hour. The average grain size in the blanks was 85-120 microns. The billets were rolled at the KhTPR mill to a final size of 61.2 × 59.6 mm and 59.6 × 58 mm. The pipes were cut into measured lengths and annealed in vacuum at a temperature of 980 ° C for 1 hour. The grain size was 30-40 microns. The resulting pipes were used as a diffusion barrier in the manufacture of Nb ₃ Sn superconductors.

A new technical result was obtained, consisting in the fact that it circumvents the shortcomings of previously used methods for producing tubular and sheet products from Nb and Ta and, most importantly, provides the possibility of obtaining a wide range of blanks for diffusion barriers with the required dimensional, strength, plastic, for the production of superconductors and structural characteristics. Moreover, sheet diffusion barriers in the form of cylindrical shells and tube barriers can be manufactured using the same head operations in the process of redistribution of refractory barrier materials, which unifies the stages of the production of blanks for diffusion barriers and thereby greatly simplifies their manufacture.

In addition, the proposed method for producing thin-walled cylindrical billets allows the rolling method to obtain pipes of Nb and Ta up to 10 meters in length. Such pipes can also be used in such fields of technology as the chemical industry, aircraft and space engineering.

Information sources

1. Garber M., Suenaga M., Sampson W. B. and Sabatini R. L., 1985, "Effect of CuTi compound Formation on the Characteristics of NbTi Accelerator Magnet Wire", IEEE Trans. Nucl. Sci., 32.3681-3683.

2. Larbalestier D.C., Lee P.L. and Samuel R.W. <1986, "The Growth of Intermetallic Compounds at a Copper-Niobium-Titanium Interface", Abs. Cryog. Eng. (Materials) 32, 715-722.

3. Faase K.L., Lee P.L., McKinnelly J.C. and Larbalestier D.C., 1992, "Diffussional Reaction Rates through the Nb Wrap in SSC and Other Advanced Multifilamentary Nb-46.5wt.% Ti", Composites Adv. Cryo. Eng (Materials) 38, 723-730.

4. Shikov A.K., Nikulin A.D., Silaev A.G., Vorobyova A, E., Pantsyrny V.I., Vedernikov G.P., Dergunova E.A., Potanina L.V., Plashkin E.I., Sudyev S.P. “Development of superconductors for ITER magnetic systems in Russia”, Non-ferrous metallurgy, No. 1, 2003, pp. 36-43.

5. "Plastic deformation of refractory metals." A.V. Krupin, V.Ya.Soloviev. Metallurgy, 1971, p. 185-191, 264 and 281-285.

6. "Pressure treatment of refractory metals and alloys." N.I. Korneev, S. B. Pevzner, E. I. Razuvaev, V. B. Emelyanov “Metallurgy”, 1975, pp. 117-119 and 122-123, 261-265.

7. "Pressure treatment of refractory metals and alloys." N.I. Korneev, S. B. Pevzner, E. I. Razuvaev, I. G. Skugarev, Metallurgy, 1967, pp. 116-119 and 122-123.

8. "The technology of production of niobium and its alloys." M. B. Maltsev, A. I. Baykov, V. Ya. Soloviev, Metallurgy, 1966, pp. 201-205.

Claims (7)

1. A method of manufacturing a thin-walled tubular billet from an Nb or Ta ingot for forming a diffusion barrier in superconductors, including homogenizing annealing of the ingot, applying a protective coating of copper to the ingot and its deformation, characterized in that the homogenizing annealing is carried out in the temperature range 1200-1350 ° C , a protective coating of copper is applied by a galvanic method, then the ingot is heated at a temperature of 800-900 ° C, which is lower than the recrystallization temperature of niobium or tantalum, and deformed by extrusion to obtain the first the tubular billet, which is subjected to mechanical processing followed by the application of a protective coating of copper by the galvanic method, the first tubular billet is heated at a temperature of 800-900 ° C, which is lower than the recrystallization temperature of niobium or tantalum, and deformed by extrusion to obtain a second tubular billet, subjected to mechanical processing then recrystallization annealing is carried out in the temperature range from 950 to 1250 ° C, cold rolling to a predetermined size of the tube billet and recrystallization annealing in the range zone temperatures from 950 to 1250 ° C. 2. The method according to claim 1, characterized in that the first pipe billet is obtained by the method of backward extrusion. 3. The method according to claim 1, characterized in that for the formation of a copper protective layer on the inner surface of the first tube billet, when extruding under the stitch, a copper gasket is laid. 4. A method of manufacturing a thin-walled tubular billet from an Nb or Ta ingot for forming a diffusion barrier in superconductors, including homogenizing annealing of the ingot, applying a protective coating of copper to the ingot and its deformation, characterized in that the homogenizing annealing is carried out in the temperature range 1200-1350 ° C , a protective coating of copper is applied by a galvanic method, then the ingot is heated to a temperature of 800-900 ° C, which is lower than the recrystallization temperature of niobium or tantalum, and deformed by extrusion to obtain the first the prefabricated billet, which is subjected to mechanical processing followed by the application of a protective coating of copper by the galvanic method, the first pipe billet is heated and deformed by extrusion to obtain a second pipe billet, subjected to mechanical processing, the second pipe billet is cut and straightened to obtain a flat billet which is subjected to recrystallization annealing in the temperature range from 950 to 1250 ° C, carry out its cold rolling to obtain a sheet of a given size, fold it into a pipe preparation and conduct final recrystallization annealing in the temperature range from 950 to 1250 ° C. 5. The method according to claim 4, characterized in that the first pipe billet is obtained by the method of backward extrusion. 6. The method according to claim 4, characterized in that for the formation of a copper layer on the inner surface of the first tube billet, when extruding under the pierce, a copper gasket is laid. 7. The method according to claim 7, characterized in that the rolling of the flat workpiece is carried out in two mutually perpendicular planes.