Method of production of thin-walled tubular billet from nb or ta ingot for forming diffusion barrier in superconductors (versions)

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

 

The invention relates to the field of electrical low temperatures and can be used in the manufacture of superconducting wires, designed for use at the temperature of liquid helium in magnetic systems of particle accelerators, fusion devices, energy storage, medical NMR imaging, cryoturbation and creatorof. The invention can also be used for other applications that require thin-walled tubes of Nb and TA and alloys on the basis of Nb and TA, 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 NbTi alloy and intermetallic compound Nb3Sn. As barrier materials are usually used Nb and TA. Diffusion barriers of the niobium used in the construction of NbTi superconductors to prevent interaction on the border of the NbTi alloy/copper, leading to the formation of brittle intermetallic systems Ti-Cu, which cause breakage of the individual filaments and wires in General and reduce its electrical characteristics [1-3]. In the structures of superconductors based intermetallic compound Nb3Sn used niobium and tantalum barriers for p is edatrexate penetration of tin in copper, lead to the deterioration of the stabilizing properties of copper [4]. In this case, niobium or tantalum barriers placed between tin bronze and copper matrix. Currently using niobium and tantalum barriers in the form of a folded sheet (shell), tape or foil [1-4]. Usually Nb and TA barriers lay in mono - or multi-fiber assemblies before extrusion of the composite.

The disadvantages of the barrier sheet, tape or foil is the need to create overlapping edges, next to which subsequent redistribution is thinning and even rupture, and the need to provide large gaps between the sides of the sheet, strip or foil and copper glass during formation of the composite billet. The presence of overlap and the need for security clearances leads to asymmetry in the Assembly of the composite billet, change the fill factor on the superconductor from the Assembly to the Assembly and reduce the quality of the superconducting wires.

The main feature of barrier materials in the form of a folded sheet, strip, foil, used for the manufacture of diffusion barriers in superconductors is that they must possess the combination of properties required for further joint deformation in the composite containing many other elements. This property also includes die requirements for grain size and mechanical properties. The barrier material should have a uniform small grain size of 20-60 μm, the yield strength of 250 MPa and elongation of 45-60%.

Niobium and tantalum for diffusion barriers must be sufficiently flexible to withstand without tearing a large deformation (stretching 9×108) in the subsequent manufacturing superconducting wires from the source of raw material to the finished wire. Therefore, for these purposes niobium and tantalum electron beam melting. One of the drawbacks of the materials of the electron-beam melting is the heterogeneity of the distribution of gas impurities, resulting in hardness and ability to deform to such heterogeneous materials. So, according to our data in the niobium ingot with an average hardness HB=56,5 kg/mm2the difference between the hardness values up to 1.5 times, and in the process of manufacturing superconductors due to the heterogeneity of the plastic characteristics of the original niobium local thinning and even the gap of niobium diffusion barrier.

Large grains, typical of cast structure of pure niobium and tantalum, contribute significantly particularly in the technology of their processing pressure. Primary processing of niobium and tantalum ingots is the destruction of the cast structure by extrusion or forging. Modes extrusion depend on the parameters of keusahawanan. As a rule, it is "hot" or "warm" processing is performed using coatings or membranes, because the surface gasanalysis can seriously reduce the plasticity of the material. After the destruction of the cast structure further processing pressure is direct or reverse extrusion and rolling.

The highest symmetry of the Assembly of the composite billet through small gaps between its components can be achieved when using a pipe barriers. They provide high accuracy of dimensions of the elements of the composite blanks for the manufacture of superconductors, good geometry, stabilization of the fill factor and high quality superconducting wire.

If for forming a diffusion barrier in superconductors to use pipes, they should be rolled and having an outer diameter of from 4 to 115 mm with the wall thickness of 0.1 to 3.5 mm, and a uniform fine grain size of 20-60 μm, the yield strength of 250 MPa and elongation of 45-60%. This combination of size, strength and plastic characteristics of the obtained thin-rolled pipe is most fully meet the requirements for the manufacture of the barrier layer in composite blanks in the manufacture of superconducting wires.

Manufactured in the present vremyaproletnogo thin-rolled pipes made of niobium and tantala have a maximum size of 27× 3 mm [5] and 38×0.56 mm [6]that does not match the size of pipe required for the manufacture of most superconductors (70-115 mm). Thin-walled pipes of large diameter are encouraged to obtain or welding of sheet stock, bent on a cylindrical mandrel [6], or by cold rolling the welded workpieces from cold rolled strips [5], which is unacceptable for the production of superconductors.

A known method of manufacturing tubes of niobium and tantalum [5], which includes the operation of applying glass powder onto the hot ingot with a diameter of 150-250 mm with the formation of a protective layer of molten glass, pressing (squeezing) of a rod with a diameter of 80-120 mm at a temperature of 1500-1550°With, cutting the rod into pieces with a length of 100-150 mm, obtaining a hollow billet (checkers) by drilling, vacuum homogenizing annealing the workpiece at a temperature of 1300-1350°C for 3-4 hours, extrusion of the hollow billet (checkers) in round billet with a diameter of 30-60 mm at a temperature of 1200-1300°With the rolling of the billet mills HPT and roller mills hptr with receiving tubes, recrystallization annealing tubes in vacuum at a temperature of 1280°within 2 hours.

This method of manufacturing tubes of niobium has a number of disadvantages.

1. Heating of the ingots to a temperature 1500-1550°above the recrystallization temperature, leads to reduced the th degree of the accumulated deformation and temperature rise subsequent vacuum recrystallization annealing, which in turn leads to an increase in the average size of recrystallized grains and reduce the plastic properties of the material.

2. Vacuum homogenizing annealing at a temperature of 1300-1350°C for 3-4 hours is carried out after pressing rod-blanks, which also leads to a decrease in the accumulated deformation and temperature rise subsequent vacuum recrystallization annealing, which in turn leads to an increase in the average size of recrystallized grains and reduce the plastic properties of the material.

3. The use of glass powders as a protective layer and a lubricant during the extrusion ingots requires special safety measures when applying the powder on the hot bar in terms of production. Furthermore, the pressing require further in-depth mechanical processing.

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

5. The method makes it possible to obtain tubes with the combination of properties required for Sagatova is, used as diffusion barriers in the manufacture of superconductors.

Known another method of manufacturing tubes of niobium and tantalum [7], according to which, extrusion of tubes of the pre-deformed billets produced at temperatures 1000-600°C and below. As lubrication and protection is used graphite and copper foil on the inner and outer surface of the workpiece. As the original blanks for the manufacture of thin-walled pipes are extruded pipe or workpiece in the form of glasses, obtained by deep drawing of the sheet. Pipes are manufactured by rolling or by drawing through a Spinneret in a cold state. In this way, are made of seamless pipes with outside diameter from 0.3 to 28.5 mm and the minimum inner diameter of 0.1 mm and the wall thickness of 0.1 mm

This method of manufacturing a pipe also has several disadvantages.

1. Using a copper foil as a protective layer and a lubricant during the extrusion ingots requires, firstly, the manufacture of foil and, secondly, deep machining of the workpiece due to the large surface relief of the pressed blanks.

2. In addition, according to this method, tubing only small diameter (tantalum pipes up to a diameter of 28.5 mm with wall thickness of 0.87 mm and niobium pipe diameter 27 mm, that is the woman of the wall 3 mm). The method does not cover the range required for the production of superconductors pipes made of niobium and tantalum (diameter 4-115 mm, wall thickness of 0.1-3.5 mm).

There is also known a method of manufacturing sheets of Nb [8], which includes the operation of applying glass powder onto the hot ingot diameter 120-250 mm with the formation of a protective layer of molten glass, extrusion or forging flat plate (in) section 40×120 mm2and 60×80 mm2ingots of 120-150 mm diameter at a temperature of 1400-1550°With a higher recrystallization temperature, editing and cutting of workpieces, a mechanical surface treatment, etching, recrystallization annealing at a temperature of recrystallization 1200-1300°C for 1-2 hours and cold rolling at a rolling mill to obtain a sheet with a thickness of 0.8-1.0 mm in size up to 600-800×1500-2000 mm, the disadvantages of this method include the following.

1. The use of glass powder as a lubricant during the extrusion ingots, which requires special safety measures when applying powder onto the hot ingot production process.

2. A significant trough and screw reversal obtained stunk axis deformation, causing the need editing before machining of a surface.

3. Long and deep machining the surface of stunk because otsutstvie necessary ploskoparallyel faces after editing, leading to a significant loss of metal.

4. Uneven development of cast structure in the process of pressing the in, leading to the formation of inhomogeneous grain structure during subsequent recrystallization heat treatment. The size of recrystallized grains during this ranges from 10 to 120 μm in one stance, which is unacceptable for use in the manufacture of superconductors.

The technical task of the present invention to provide a thin-walled tubular pieces of niobium and tantalum for use as diffusion barriers with a given set of properties, providing the ability to further deformation with a total extract of up to 9×108in the manufacture of superconductors and ensure the prevention of unwanted diffusion processes in the redistribution of manufacturing superconductors.

The solution of this problem is achieved by the fact that, compared with the equivalent [7], which involves in the manufacture of thin-walled tubular workpieces from ingot Nb or TA homogenizing the ingot annealing, applying a protective coating of copper and the subsequent deformation, a method of manufacturing thin-walled tubular workpieces from ingot Nb or TA for forming a diffusion barrier in superconductors (including homogenizing the ingot annealing, namestitvenega coating of copper on the ingot and its deformation), when homogenizing annealing is carried out in the temperature range of 1200-1350°With a protective coating of copper applied by electroplating, and then the ingot is heated and deformed by squeezing with the first tubular workpiece which is subjected to mechanical treatment followed by the application of a protective coating of copper by electroplating, the first tubular workpiece is heated and extruded to obtain a second tubular workpiece which is subjected to mechanical treatment followed by recrystallization annealing in the temperature range from 950 to 1250°cold rolling to a specified size and recrystallization annealing in the temperature range from 950 to 1250°With heating prior to extrusion and ingot, and the first billet is carried out at a temperature of 800-900°S, which is below the recrystallization temperature of the material.

In the particular case of the method of the first tubular preform produced by the method of backward extrusion.

In another particular case, the method for forming a copper protective layer on the inner surface of the hollow billet during extrusion under the drift-pin strengthening enclose the copper gasket. The thickness should be not less than 3 mm.

In another embodiment, the solution of the technical problem is achieved by the fact that the method of manufacturing t is Kostanai billets from ingots of refractory material is Nb or TA for forming a diffusion barrier in superconductors, includes homogenizing the ingot annealing, applying a protective coating of copper on the ingot and its deformation, in which the homogenizing annealing is carried out in the temperature range of 1200-1350°With a protective coating of copper applied by electroplating, and then the ingot is heated and deformed by squeezing with the first tubular workpiece which is subjected to mechanical treatment followed by the application of a protective coating of copper by electroplating, the first tubular workpiece is heated and extruded to obtain a second tubular workpiece which is subjected to mechanical treatment, the second tubular workpiece is cut and straighten with getting flat blanks, then hold her cold rolling to obtain sheet of the specified size, which is rolled into a cylindrical billet, and conduct the final recrystallization annealing, the heating before the extrusion is carried out at a temperature of 800-900°S, which is below the recrystallization temperature of the material, and cold-rolled flat blanks conduct recrystallization annealing, which, as the final recrystallization annealing, is carried out in the temperature range from 950 to 1250°C.

In the particular case of implementation of this method first round billet is produced by the method of backward extrusion.

In another customlocale of the method for forming a copper protective layer on the inner surface of the first tubular billet during extrusion under the drift-pin strengthening enclose the copper gasket. The thickness should be not less than 3 mm.

In the proposed method (in both variants) the ingot is first subjected to vacuum (104-105mm Hg) homogenizing annealing at temperatures above 1200°S, but not more than 1350°With the result that there is a partial degassing, the alignment of the content of gaseous impurities and, as a consequence, the hardness of the cross-section of the ingot. The temperature of the annealing is selected, on the basis that it should provide a sufficiently high diffusion rate of gaseous impurities, so that it was economically feasible, but not lead to the growth of grain. The diffusion rate primary gas impurities of oxygen in niobium at a temperature of 1200°C is 10 mm/hour, which is sufficient to align its concentration in the ingot for 8-10 hours. The temperature rise of a homogenizing annealing leads to an increase in the rate of diffusion, but in pure niobium at temperatures above 1350°With increasing grain size, which is undesirable for subsequent processing.

After homogenizing annealing on the surface of the ingot cause galvanic copper coating thickness of 150-200 microns, providing protection from oxidation during heating and at the same time serving padmasani layer during extrusion. The thickness of the copper coating sufficient to protect against oxidation, however, offer protection the second coating has a thickness much less than used with the present coating in the form of a copper foil or on the basis of glass. This reduces the surface relief moulded blanks, resulting in joint deformity more solid components of the composite and soft copper large thickness in lack of backwater from the tool, to correct which you want deep machining of the surfaces of the extruded billet.

In the proposed method, the process of pressing is carried out at a temperature of 800-900°S, which is below the recrystallization temperature, which allows to increase the degree of accumulated strain and reduce the temperature of the subsequent vacuum recrystallization annealing, which in turn reduces the average size of recrystallized grains and improve the plastic properties of the material. The temperature of recrystallization of pure niobium and tantalum depends on the content of gaseous impurities and the degree of prior deformation. When the content of gas impurities on the level stipulated in modern standards of refractory materials electron-beam melting, and when the degrees of deformation, usually used during extrusion ingots, it is 1150-1250°for niobium and 900-1000°for tantalum.

Accumulated in the material after low-temperature extrusion de is armacia helps shape after vacuum recrystallization annealing finishing a thick-walled tubular workpiece (second round billet), having uniform melkosemennoyi structure with a grain size up to 150 μm.

This thick-walled tubular blanks by cold rolling mills tube rolling is made of thin-walled pipes 4-115 mm with a ratio of DTr/tarticle170 (where DTrthe diameter of the outer pipe, tarticlethe wall thickness of the pipe).

The resulting thin-walled rolled pipe (cylindrical shell) made of refractory material, characterized by the fact that it has a size (diameter 4-115 mm, wall thickness of 0.1-3.5 mm), structure (uniform small grain size of 20-60 μm) and properties (yield strength of 250 MPa at a relative elongation up to 45-60%), necessary for the formation of high-quality diffusion barriers in the process of manufacturing superconductors. These properties provide a high plasticity of diffusion barriers in the process of manufacturing superconductors.

Formed thick-walled tubular workpiece with a uniform fine-grain structure can be cut along the axis of deformation into two or more parts and straighten, resulting in a gain of a flat rectangular blanks, which rolls in the cold in two mutually perpendicular directions on the leaf mills for the production of sheets of different thickness, which can be subjected to a final vacuum rcris allization annealing to ensure required for diffusion barriers structural, strength and plastic characteristics.

Leaves rolled up on rollers for receiving the shell, which is subjected to a final vacuum recrystallization annealing to ensure required for diffusion barriers structural strength and plastic characteristics.

Examples of specific performance

Example 1. Niobium ingots with a diameter of 250 mm and 150 mm and a height of 800 mm was cut into the workpiece. On the end sections of the workpieces measured hardness in 13 points on each end. Billet homogenized in a vacuum at a temperature of 1300°C for 8 hours and again measured the hardness. As a result of partial degassing and redistribution of impurities during annealing in the blanks there are no areas of high hardness. Cast billets with a diameter of 250 mm was ground on a diameter of 245 mm, and then they were applied to the copper layer with a thickness of 150-200 μm by an electroplating deposition of sulfate in the electrolyte at a current density of 1.5 to 2.5 A/DM2. Thereafter, the workpiece was dried in air, coated with graphite grease and extruded into a rod with a diameter of 150 mm at a temperature of 930°C, cut on the workpiece height 150 mm, ground on the diameter 148,5 mm and re-applied galvanic copper coating. Cast billets with a diameter of 150 mm and a height of 150 mm was ground on a diameter up to 148,5 mm and Then in all the blanks Provo is or drilling for forming an internal centering cylindrical holes with a diameter of 21 mm Thereafter, the workpiece was applied to the copper layer with a thickness of 150-200 microns. The workpiece was dried in air and daubed with grease based on graphite. After heating in a resistance furnace at a temperature of 800°C for 1.5-2 hours billet was sewn on the vertical press-drift-pin strengthening diameter 80-84 mm overlay the Central copper strip under the drift-pin strengthening for forming a copper protective layer on the inner surface. After trimming the bottom side and the machining of the inner and outer surfaces of the obtained hollow billet size 148,5×83-87×250 mm re-applied galvanic copper coating. Then hollow workpiece was dried, put graphite grease was heated at a temperature of 950°and he drew in billet size 106,5×82-86×800 mm After machining billet size 103,5×83,5 to 87.5×780 mm was subjected to vacuum annealing at a temperature of 1250°C for 2 hours. The average grain size in the tube blanks were 200-250 microns.

For the manufacture of tubular niobium barriers of size 63×61,6 mm billets rolled on the mill HPT to size 92×76 mm in one transition, then the mill chptr to the finished size 63×61,6 mm in three transition. Ten billets for the manufacture of pipe barriers dimensions 85,5×84,1 mm, 83×81,4 mm and 81.5×78.5 mm p is over on the mill chptr to the finished size 5 transitions. The obtained pipe cut to length and annealed in vacuum. After annealing the pipe had uniform fine grain size 20-40 μm, the yield strength of 130 MPa and elongation of 45%.

Pipe used as a diffusion barrier in the manufacture of NbTi superconductors. High quality barriers, uniformity of structure and properties, there are no gaps and local thinning of the barrier surrounding the fiber, allowed to increase the duration and temperature of heat treatment in the manufacture of wires and raise the critical current density up to 2900 A/mm2.

Example 2. For sheet niobium barriers billet size 103,5×83,5 to 87.5×780 mm cut perpendicular to the axis on a lathe and along on a milling machine with the formation of 4 parts of the coupling. Then, the semi-cylinders straightened on a hydraulic press with force 2000 TC between plane-parallel strikers before the formation of a flat rectangular workpiece size 385×10,1×146 mm Rectangular billets rolled in two mutually perpendicular directions on the sheet rolling mills of the type Duo in sheet size 250×1×2283 mm Sheets cut to card size 242×1×420 mm Of each card on rollers with diameters of 80 and 40 mm were formed shell, which after vacuum annealing used in the quality of the diffusion barrier at the manufacture of small batch sizes NbTi superconductors. The grain size after recrystallization annealing Nb pipe and sheet barriers were 40-60 microns.

Example 3. Three tantalum ingot diameter 116-118 mm and a height of 160-180 mm was applied electroplated copper layer with a thickness of 150-200 mm, was heated to a temperature of 700°C for 1.5 hours and had two systems in a container with a diameter of 125 mm After machining and re-deposition of copper coatings blanks were transpierced by the drift-pin strengthening diameter 68 mm, Then cut off the bottom part and again subjected to mechanical processing. On the hollow billet inflicted electroplated layer of copper was heated to 850°C for 1.5 hours and was squeezed in the tube billet size 80×65×800 mm After machining of the workpiece size 78×67×780 mm was subjected to vacuum annealing at a temperature of 1050°C for 1 hour. The average grain size in the blanks was 85-120 μm. Billet rolled on the mill chptr to the final size 61,2×59,6 mm and 59.6×58 mm Pipe cut to length and annealed in vacuum at a temperature of 980°C for 1 hour. The grain size was 30-40 μm. The obtained tube was used as a diffusion barrier in the manufacture of Nb3Sn superconductors.

Received a new technical result consists in the fact that it allows you to bypass the disadvantages of the previously used methods proceduralnych and sheet products from Nb and TA, and most importantly, allows a wide range of workpieces to diffusion barriers required for the production of superconductors size, strength, plastic and structural characteristics. And leaf diffusion barriers in the form of cylindrical shells and pipe barriers can be manufactured using the same head of operations in the process of redistribution of refractory barrier materials that unifies the stages of production of blanks for diffusion barriers and thereby greatly simplifies their manufacture.

In addition, the proposed method of producing thin-walled cylindrical billets allows by rolling the tube to get from Nb and TA to 10 m in length. These tubes can also be used in such fields as chemical industry, aviation and space engineering.

Sources of information

1. Garber, M., Suenaga, M., W.B. Sampson 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., P.L. Lee 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 D.C. Larbalestier, 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., Vorobjova,E., Pancerny VI, the Veda is nicks G.P., Dergunova E.A., Potanin L.V., Plaskin AI, Sudev S. p. "Development of superconductors for magnetic systems of ITER in Russia, Nonferrous metallurgy, No. 1, 2003, p.36-43.

5. "Plastic deformation of refractory metals". Averroes, Wasalive. "Metallurgy", 1971, p.185-191, 264 and 281-285.

6. "The pressure treatment of refractory metals and alloys". Nearnet, Sbitar, Euirosai, Vboolean metallurgy, 1975, s-119 and 122-123, 261-265.

7. "The pressure treatment of refractory metals and alloys". Nearnet, Sbitar, Euirosai, Igitkhanov, "metallurgy", 1967, p.116-119 and 122-123.

8. "Technology for the production of niobium and its alloys". Mvela, Ayiku, Wasalive, metallurgy, 1966, s-205.

1. A method of manufacturing a thin-walled tubular workpieces from ingot Nb or TA for forming a diffusion barrier in superconductors, including homogenizing the ingot annealing, applying a protective coating of copper on the ingot and its deformation, wherein the homogenizing annealing is carried out in the temperature range of 1200-1350°With a protective coating of copper applied by electroplating, and then the ingot is heated at a temperature of 800-900°S, which is below the recrystallization temperature of the niobium or tantalum, and is deformed by squeezing with the first tubular workpiece which is subjected to mechanical treatment with posledovaniem protective coating of copper by electroplating, the first tubular workpiece is heated at a temperature of 800-900°S, which is below the recrystallization temperature of the niobium or tantalum, and is deformed by squeezing with getting the second billet, subjecting it to mechanical treatment followed by recrystallization annealing in the temperature range from 950 to 1250°cold rolling to a given size of pipe billets and recrystallization annealing in the temperature range from 950 to 1250°C.

2. The method according to claim 1, characterized in that the first tubular preform produced by the method of backward extrusion.

3. The method according to claim 1, characterized in that for forming a copper protective layer on the inner surface of the first tubular billet during extrusion under the drift-pin strengthening enclose the copper strip.

4. A method of manufacturing a thin-walled tubular workpieces from ingot Nb or TA for forming a diffusion barrier in superconductors, including homogenizing the ingot annealing, applying a protective coating of copper on the ingot and its deformation, wherein the homogenizing annealing is carried out in the temperature range of 1200-1350°With a protective coating of copper applied by electroplating, and then the ingot is heated to a temperature of 800-900°S, which is below the recrystallization temperature of the niobium or tantalum, and is deformed by squeezing with the first is rubey workpiece, which is subjected to mechanical treatment followed by the application of a protective coating of copper by electroplating, the first tubular workpiece is heated and deformed by squeezing with getting the second billet, subjecting it to mechanical processing, the second tubular workpiece is cut and straighten with getting a flat workpiece which is subjected to recrystallization annealing in the temperature range from 950 to 1250°With, hold her cold rolling to obtain a sheet of a given size, roll it into a tube together and spend the final recrystallization annealing in the temperature range from 950 to 1250°C.

5. The method according to claim 4, characterized in that the first tubular preform produced by the method of backward extrusion.

6. The method according to claim 4, characterized in that for forming the copper layer on the inner surface of the first tubular billet during extrusion under the drift-pin strengthening enclose the copper strip.

7. The method according to claim 7, characterized in that the rolling of flat blanks is carried out in two mutually perpendicular planes.



 

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1 ex

FIELD: processes and equipment for diffusion welding of tubular adapters of zirconium and steel sleeves.

SUBSTANCE: method comprises steps of placing sleeve of zirconium alloy inside steel sleeve and heating them in vacuum till diffusion welding temperature; then compressing welded surfaces due to expanding zirconium sleeve by means of roller expander; after diffusion welding cooling adapter in temperature range in which zirconium alloy has no phase containing α-zirconium and β-zirconium; subjecting zirconium sleeve to hot deformation by depth no less than 0.5 mm at reduction degree no less than 10%; cooling adapter till temperature range 540 - 580°C and keeping it in such temperature range no less than 30 min.

EFFECT: simplified method for making adapters having improved corrosion resistance in hot water and steam.

FIELD: non-ferrous metallurgy; methods of titanium alloy bricks production.

SUBSTANCE: the invention is pertaining to the field of non-ferrous metallurgy, in particular, to the brick made out of α+β titanium alloy and to a method of its manufacture. The offered brick consists of the following components (in mass %): aluminum - 4-5, vanadium - 2.5-3.5, iron - 1.5-2.5, molybdenum - 1.5-2.5, titanium - the rest. At that the alloy out of which the brick is manufactured, contains - 10-90 volumetric % of the primary α-phase. The average grain size of the primary α-phase makes 10 microns or less in a cross-section plain parallel to the brick rolling direction. Elongation of grain of the primary α -phase is the four-fold or less. The offered method of manufacture of the given brick includes a stage of a hot rolling. At that before the stage of the hot rolling conduct a stage of the alloy heating at the surfaces temperature (Tβ-150)- Tβ°C. During realization of the stage of the hot rolling the surface temperature is kept within the range of (Tβ-300)-( Tβ -50)°C, and the final surface temperature, that is a surface temperature directly after the last rolling, makes (Tβ-300)-( Tβ-100)°C, where Tβ is a temperature of α/β-transition. The technical result of the invention is formation of a brick out of the high-strength titanium alloy having a super pliability, excellent fatigue characteristics and moldability.

EFFECT: the invention ensures production of a brick out of the high-strength titanium alloy having a super pliability, excellent fatigue characteristics and moldability.

7 cl, 7 dwg, 21 tbl, 2 ex

FIELD: metallurgy, namely processes for forging titanium alloys and blank of such alloy suitable for forging.

SUBSTANCE: method comprises steps of preparing blank and forging it. Forging is realized at providing mechanical hardening factor equal to 1.2 or less and at difference of hardness values between central (along width) zone and near-surface zone equal to 60 or less by Vickers. Factor of mechanical hardening is determined as HV(def)/HV(ini), where HV(ini) - hardness of titanium alloy blank before forging; HV(def) -hardness of titanium alloy blank after forging at forging reduction 20%. Forging may be realized at deformation rate from 2 x 10 -4 s -1 to 1s-1 while keeping relations (T β - 400)°C ≤ Tm ≤ 900°C and 400°C ≤ Td ≤ 700°C, where Tβ (°C) -temperature of β-phase transition of titanium alloy, T m(°C) - temperature of worked blank; Td(°C) - temperature of die set. Blank has factor of mechanical hardening 1.2 or less and difference of hardness values between central (along width) zone and near-surface zone equal to 60 or less by Vickers.

EFFECT: possibility for forging titanium alloy blanks at minimum difference of material properties along depth, simplified finishing of blank surface after forging, reduced cracking of blank material, good workability of blank with favorable ductility and fatigue properties.

8 cl, 5 tbl, 6 dwg, 4 ex

FIELD: metallurgy, namely rolling line operation method and rolling line for realizing it.

SUBSTANCE: line for rolling strip material includes several rolling stands arranged one after another in direction of rolling process. Said rolling stands may be rotated around rotation axis that is practically normal to rolling direction. In such line optimized passing of strip for achieving target result of rolling is sustained. In order to realize it, setting value in one or in each rolling stand is set according to measured contour of end of strip had been rolled. According to invention other setting units may be used.

EFFECT: enhanced quality of rolled materials.

22 cl, 2 dwg, 1 ex

FIELD: rolled stock production, namely stand for cold or hot rolling strip materials of different kinds of steel.

SUBSTANCE: rolling stand includes backup and rolling rolls are mounted with possibility of rotation in chocks arranged at both sides in guides of framework of housing. Rolls may be moved for regulating inter-roll gap and they may be additionally shifted by means of horizontal cylinder-piston units mounted in framework at least of one side for regulating clearance. At least at one side of housing, rolling roll chocks are guided by means of cylinder-piston unit arranged in framework and by means of supporting member on end face of piston. Guides of said chocks for motion without clearance when vertical drive of roll mounting is turned off and said chocks are made with possibility of pressing to other side of housing and drawing off when vertical drive of roll mounting is turned on.

EFFECT: lowered wear degree of rolls, elimination of clearance in rolling roll chocks in their vertical guide at rolling process without using hydraulic coupling with chocks.

13 cl, 9 dwg

FIELD: rolled stock production, namely apparatuses for moving rolled bars and sheets between roller tables, for example in sheet rolling mills.

SUBSTANCE: apparatus includes parallel roller tables and mechanism for transmitting rolled piece from one roller table to other. Said mechanism includes tie rods with rack drive for horizontally moving them and transporting liners joining in pairs ends of said tie rods. Rack drive unit for horizontally moving tie rods is mounted between parallel roller tables. Tie rods are provided with runners mounted with possibility of motion in shaped guiding members arranged between adjacent rollers of roller tables along the whole length of tie rods stroke. Parallel roller tables are joined by means of additional guiding members in intervals between said shaped guiding members. Additional and shaped guiding members are provided in zone between roller tables with supporting rollers whose mounting level exceeds that of rollers of roller tables.

EFFECT: simplified design, lowered size of apparatus.

3 dwg

FIELD: sealing device for bearing assembly of roll of rolling stand.

SUBSTANCE: in sealing device of roll bearing assembly, to roll journal corresponds at least one elastic sealing member embracing it and engaging with sealed surface. Sealing member and(or) sealed surface rest upon at least one elastic supporting member on its holder. Said elastic supporting member has rigidity less than that of sealing lugs of sealing member. Rigidity of elastic member and or) value of radial compensation motion of elastic supporting member is preliminarily adjusted.

EFFECT: lowered wear degree, increased useful life period of sealing members.

10 cl, 2 dwg

FIELD: plastic working of metal in vertical and universal stands of rolling mill, namely mechanisms for transmitting rotation of motor to vertical rolls of rolling stand of strip rolling mill.

SUBSTANCE: drive unit of vertical rolls of rolling stand includes mounted in frame: electric motor, reduction gear with outlet shafts, spindles, mechanisms for lifting and descending. Spindles are joined through upper spline joints with outlet shafts of reduction gear and they are joined through lower spline joints with rolls of rolling stand. Mechanism for lifting and descending are provided with power cylinders for lifting and descending lower spline joints. Each mechanism for lifting and descending lower spline joints is in the form of pneumatic cylinder mounted along the same axis as shaft of spindle. Base of pneumatic cylinder is mounted on upper spline joint. Hollow rod of pneumatic cylinder is joined with lower spline joint with possibility of fixed its positions in spindle shaft.

EFFECT: lowered labor consumption, shortened time period for changing rolls.

7 cl, 3 dwg

FIELD: rolled stock production, namely processes for rolling metallic strip in continuous hot and cold rolling mills.

SUBSTANCE: method is realized on simultaneous control of lengthwise and crosswise thickness difference of strip at rolling process. Crosswise thickness difference is controlled by means of apparatus for counter bending rolls. Lengthwise thickness difference is controlled due to changing value of back tension of strip by acting upon screw-down mechanisms in previous, along rolling process direction, rolling stand of mill. Back tension is also may be changed due to varying revolution number of rolls of previous along rolling process direction rolling stand of mill.

EFFECT: enhanced accuracy of geometry size of strip in lengthwise and crosswise directions at rolling strip in continuous rolling mills equipped with counter bending apparatuses.

4 cl, 2 dwg

FIELD: metallurgy, namely processes for making bandaged parts of metallurgical equipment in the form of bodies of revolution subjected to action of outer thermal loads, for example supporting rollers of rotary furnaces, drying drums, conveyer rollers, possibly in plants for continuous casting of metal combined with rolling mills.

SUBSTANCE: part includes inner cylindrical member having annular turning in its mounting surface and embracing its bandage. According to invention mounting surfaces of inner cylindrical member and bandage are double-step ones. Bandage includes two portions corresponding to its steps. Turning is formed along boundary of steps in central zone of inner cylindrical member. On inner edges of mounting surfaces of both portions of bandage there are shoulders corresponding to turning and having height consisting of 0.002 - 0.015 of diameter of mounting surfaces of bandage portions. Depth of turning exceeds height of shoulders of respective portions of bandage by 1.1 - 2 times. Method for making bandaged part comprises steps of forming mounting surfaces of inner cylindrical member and of bandage as double-step ones; forming bandage of two portions corresponding to said steps; forming turning on boundary of two steps in central zone of inner cylindrical member; forming on inner edges of mounting surfaces of both portions of bandage shoulders corresponding to turning and having height consisting of 0.002 - 0.015 of diameter of mounting surfaces of bandage portions; forming turning with depth exceeding height of shoulders of respective portions of bandage by 1.1 - 2 times.

EFFECT: improved operational reliability of joint in mode of high temperature and significant axial loads.

2 cl, 1 dwg, 1 ex

FIELD: rolled tube production processes and equipment, namely piercing mils for helical rolling.

SUBSTANCE: piercing mill for helical rolling includes working stand with one barrel-shaped upper roll and with two barrel-shaped lower rolls whose symmetry axes are shifted in vertical plane relative to rolling axis; rotation drive mechanism of lower rolls. Upper roll is provided with drive mechanism arranged at side of working stand opposite relative to arrangement of lower roll drive mechanism. Gorge radius Rx of upper roll is calculated with use of expression: Rx = (Rb + Ru + h)/ (Ru/Rb - h/Rb - 1) where Ru - radius of upper roll, Rb - radius of pierced blank, h - shift value of symmetry axis of lower rolls relative to rolling axis along gorge radius, is in range 0 - 200 mm.

EFFECT: improved quality of pierced sleeves, enhanced biting of blank between rolls.

4 dwg

FIELD: rolled stock production, namely apparatuses for transporting tubes.

SUBSTANCE: apparatus includes row of units having frames with supports mounted by inclination angle one to other and with possibility of mutual approaching and rotation around inclined axis. Wheels are mounted in said supports with possibility of rotation. Inclined supports with wheel in each unit are mutually shifted along lengthwise axis of apparatus and they are mutually joined and also they are joined with rotation mechanism through tie rods. The last are mutually joined through two mutually normal articulation joints. Rotation mechanism includes two tie rods with two mutually normal articulation joints and rotary coupling for joining rotation drive with inclined supports by means of rotary lever. In each unit one wheel has individual rotation drive.

EFFECT: enlarged manufacturing possibilities, increased useful life period of apparatus.

2 cl, 6 dwg

FIELD: rolled stock production, namely apparatuses for moving and rotating round rolled pieces.

SUBSTANCE: apparatus includes housing; casings with drive rollers mounted on bases with possibility of motion and inclined relative to horizontal plane; mechanism for moving casings with rollers relative to transporting axis. Said mechanism is in the form of screw mounted horizontally on supports in housing and having left-hand and right-hand threads. Apparatus also includes nuts engaging with said screws and arranged in base of casings with rollers; mechanism for rotating rollers relative to rotation axis of their casings. Said mechanism is in the form timing tie rod that connects rotary casings by means of brackets and drive joined with tie rod and including rotary tail spindle having in one end lock nut and in other end - reduction gear.

EFFECT: enhanced operational reliability and increased useful life period of apparatus due to simplified adjustment of rollers and due to their lowered wear.

3 dwg

FIELD: plastic working of metals, possibly manufacture of thin high-strength foil of titanium.

SUBSTANCE: method comprises steps of multi-pass reversing cold rolling and vacuum annealing; repeating cycle; using as initial blank titanium blank with ultra-fine grain structure provided due to intensified plastic deformation by equal-duct angular pressing process; rolling at pitch 15 - 8% for achieving total deformation 70 - 86 % per one cycle; setting number N of cycles necessary for making foil with thickness h according to mathematical expression; realizing vacuum annealing, preferably at temperature 350 -360 C for 0.5 - 1 h. Invention provides possibilities for making titanium foil with thickness up to 10 micrometers.

EFFECT: enhanced strength characteristics of titanium foil of lowered thickness with the same technological platicity7777.

2 cl, 2 tbl

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