RU2254195C1 - Axially symmetrical part forming method - Google Patents

Abstract

FIELD: plastic working of metals and alloys, possibly manufacture of large-size axially symmetrical parts for important designation, for example discs for gas turbine engines of multi-phase refractory alloys possibly on base of nickel and titanium.

SUBSTANCE: method comprises steps of rolling at controlling temperature and deformation rate at rolling in temperature range of super-plasticity; controlling temperature of rolled portion of blank and subjecting it to heat treatment; combining rolling process and out-of-contact super-plastic deformation of rolled portion of blank while selecting values of deformation rate at rolling and temperature of rolled portion of blank.

EFFECT: enhanced uniformity of material structure of part.

10 cl, 5 dwg, 1 tbl, 8 ex

Description

The invention relates to the field of processing of metals and alloys by pressure, in particular to methods for manufacturing large axisymmetric components for critical purposes, for example, disks for gas turbine engines from multiphase heat-resistant alloys, including those based on nickel and titanium.

In the manufacture of critical parts, the most important task is to improve the quality, which is ensured by a homogeneous microstructure formed in them during deformation and inherited after heat treatment, which gives the parts high operational properties. In addition, during the manufacturing process with ultrasonic testing (ultrasonic testing) of parts with such a structure, it is easier to identify various defects.

It is possible to manufacture parts such as disks without the use of expensive dies and powerful presses using the techniques described in the known method [1] for producing axisymmetric parts of railway wheels. In it, the workpiece, after a series of volumetric deformations, undergoes local deformation by rolling by means of rolls or rollers. However, the deformation modes in the rolling mills do not allow the rolling of axisymmetric parts from hardly deformable and low-plastic materials, such as heat-resistant alloys.

The possibility of manufacturing parts with a complex shape from heat-resistant alloys is ensured by deformation under conditions of superplasticity.

Closest to the technical nature of the claimed is a method of manufacturing axisymmetric parts from multiphase alloys [2]. The known method includes local shaping by rolling a billet having central and peripheral parts, using a multiphase alloy billet with a structure prepared for superplastic deformation (SPD), local billet shaping is carried out under controlled thermomechanical conditions at temperatures lying in the range above 0; 4 T _pl , where T _pl is the melting temperature, but lower than the temperature of collective recrystallization, and strain rates from 10 ² to 10 ^-3 s ^-1 , while the central part of the the workpieces are deformed by compression or compression with torsion by a tool in the form of pins, and the peripheral parts by rolling by a tool in the form of rollers having at least three independent degrees of freedom with a specific force q satisfying the condition

,

,

where σ _sn - the resistance to deformation of the workpiece material in the deformed, central before rolling, and already rolled peripheral parts; σ _sd is the stress of the flow of material in the deformable central before rolling and rolled peripheral parts.

The method includes heat treatment, the modes of which depend on the microstructure formed as a result of rolling.

The prototype also provides methods for manufacturing workpieces with a fine-grained structure prepared for superplastic deformation. These methods are laborious multi-stage processes of fractional deformation. However, they do not provide a uniform structure in massive blanks for disks. It should be noted that the maximum possible uniformity is characterized not only by small deviations of grain sizes, but also by aligned phase and chemical compositions, as well as the textureless state of the material.

The forming of the part according to the prototype method is carried out by rollers rotating around their own axes inclined to the rolling plane and regulated along and across the radius of the workpiece (not arbitrary movement across the radius, but parallel to the symmetry axis of the workpiece). In practice, these movements are usually called, respectively, radial and axial feeds. Combining the radial and axial feeds, the rollers move along a path corresponding to the contour of the part. In addition, district feed is important for shaping. It arises as a result of rotation of the workpiece around its own axis and, therefore, relative to the rollers. In rotation, the workpiece is brought either with rollers, or with pins, or both together. Feeds, measured in mm / min or mm / rev, are the main mechanical parameters of the rolling, characterizing not only the speed and degree, but also the deformation force. All of these values are sensitive to changes in feeds and increase or decrease with their increase or decrease.

When rolling under conditions of superplasticity, a part of the workpiece that has already been rolled to the required size is observed to deform non-contact with the roller. Hereinafter, non-contact deformation refers to the deformation of already rolled and formed parts of a workpiece whose surfaces do not contact the rollers until the end of rolling. Such deformation takes place due to the fact that the rolled part, which has become thinner as a result of rolling by the rollers, is subjected to force from neighboring parts loaded by rolling forces, reactive and inertial forces and moments of force, and moreover, the material in the rolled part acquires a structure homogeneity lower current stress. To prevent non-contact deformation of the rolled part in the prototype, thermomechanical conditions are regulated so that inequality is observed (1).

However, by adjusting the mechanical conditions, and more precisely the mechanical parameters, rolling by means of the above feeds, it is impossible to fulfill inequality (1). For example, tangential stresses, the values of which are known to be less than tensile normal stresses, lead to the most characteristic type of non-contact deformation of the rolled part — twisting —. If we reduce the specific force of the impact of the rollers on the peripheral part to a level less than the shear stresses, then the second part of the inequality will cease to be fulfilled, according to which the specific force should be sufficient for rolling.

As the most effective technique for satisfying inequality (1), the prototype uses a decrease in the temperature of the rolled part by cooling it, i.e. adjust the temperature of the rolled part. It should be noted here that the control of the temperature of deformation during rolling (for brevity, the term “rolling temperature" is used in the description below), i.e. in the peripheral rolled part, and temperature control in the already rolled part are different processes, due to the significant size of the rolled disks and low thermal conductivity of heat-resistant alloys. Cooling leads to the appearance of gradient and non-stationary temperature fields in the formed part of the part. The temperature in it varies from the values at which deformation does not occur, to temperatures corresponding to SPD with transition through regions with the so-called equicohesive temperature, at which the grain boundary and body have equal strength. Where plastic and hard zones are separated, there is a discontinuity in shear strain rates. With a sharp localization of the boundaries of these zones, the speed and degree of deformation in them increase intensively [3], leading at best to destruction of the material, and in the worst case to the accumulation of defects that are dangerous during operation of the product. In the region heated below the equicohesive temperature, the material undergoes small critical strains, which, as is known, lead to the emergence of nonequilibrium boundaries that create stresses in the material. During subsequent heat treatment, such boundaries become the reason for the coarsening of the structure, which is unacceptable for parts of responsible use. In the region with a temperature corresponding to SPD, to which the cooling front has not reached, there is still a localized deformation of the rolled part, leading to heterogeneity of the structure.

Thus, the prototype method provides complex techniques related to the regulation of temperatures and specific forces, which are aimed at preventing deformation of the rolled part that is not in contact with the roller, but in reality only giving it an unregulated and localized character that does not lead to an increase in the quality of parts.

The capabilities of the method are also limited by the use of blanks in which the structure is prepared, as noted above, in a laborious way [2].

The objective of the invention is to increase the uniformity of the structure of the material of the part during its manufacture due to the beneficial use of non-contact deformation.

Another objective of the invention is to expand the technological capabilities of the method through the use of initial billets with a structure capable of superplastic deformation, which is provided by traditional industrial methods of manufacturing billets. When using such blanks, the task of increasing the efficiency of the method is also solved.

The invention solves a number of additional problems associated with the creation of techniques that allow to most effectively solve the main problems.

The problem is solved by a method of manufacturing axisymmetric parts from workpieces made of multiphase alloys capable of superplastic deformation, including rolling with temperature and strain rate control during rolling in the temperature-speed range of superplasticity, temperature control in the rolled part of the workpiece, as well as heat treatment, in which , unlike the known one, rolling is combined with non-contact superplastic deformation of the rolled part of the workpiece, which is ensured by They are chosen by choosing the values of the strain rate during rolling and the temperature of the rolled part of the billet.

The tasks are also solved if:

- rolling blanks with the initial structure, the average grain size of which is equal to or greater than 20 microns, is carried out, maintaining the strain rate during rolling in the range (10 ^-3 -10 ^-1 ) s ^-1 and the temperature in the rolled part is not lower than the temperature of deformation during rolling ;

- in the manufacture of disks from two-phase titanium alloys, a curly axisymmetric billet is used having a central and peripheral part separated by undercuts to introduce rollers in front of the peripheral part, the outer D _n and inner D _{in the} diameters of the peripheral part being selected from a ratio of 1.4≤d _n / D _in ≤1.8, and the thickness Н _о - from the ratio 0.4≤ε _o = (Н _о -h _п ) / H _o ≤0.7, where ε _o is the relative compression of the peripheral part by rollers in thickness, and h _p is the thickness of the rolled part;

- in the manufacture of disks from two-phase titanium alloys, a flat axisymmetric billet is used - a washer, the thickness H _about which is selected from the ratio 0.4≤ε _о = (Н _о -h _п ) / H _o ≤0.7, where ε _o is the relative compression blanks by rollers in thickness, h _p is the thickness of the rolled part, while the inner diameter of the peripheral part D _in is determined taking into account the ratio of 1.4 ≤ D _n / D _in ≤1.8, where D _n is the outer diameter of the peripheral part, and formed before rolling it by introducing rollers into the blank;

- in the manufacture of disks from heat-resistant nickel alloys, a curly axisymmetric billet is used having a central and peripheral part separated by undercuts for introducing rollers in front of the peripheral part, the outer D _n and inner D _{in the} diameters of the peripheral part being selected from the condition 1.3≤D _n / D _in ≤1.7, and the thickness from the condition 0.5≤ε _o = (Н _о -h _p ) / H _o ≤0.7, where ε _о is the relative compression of the peripheral part by rollers in thickness, Н _о and h _п - respectively, the thickness of the peripheral part and the rolled part;

- rolling is performed by cooled rollers;

- rolling of billets with an initial structure, the average grain size of which is limited to an interval of 1-20 μm, is carried out while maintaining the strain rate during rolling in the range (10 ^-1 -100) s ^-1 and the temperature in the rolled part is not higher than the temperature of deformation during rolling;

- rolling blanks with the initial structure, the average grain size of which is less than 1 μm, is carried out, maintaining the strain rate during rolling in the range of (10 ⁰ -10 ² ) s ^-1 and the temperature in the rolled part is not higher than the temperature of deformation during rolling;

- fixation of the workpiece is performed by cooled pins;

- the rolled part is cooled by air supplied to its surface from the outlet holes of the channels made in the rollers.

The essence of the invention is the beneficial use of non-contact with the roll deformation of the rolled part in temperature-speed conditions of superplasticity as a special type of stress relaxation (use of deformation energy), leading to an increase in the uniformity of the structure.

As noted above, if the workpiece material has a relatively uniform initial structure, then after SPD, the workpiece structure becomes more uniform due to the alignment of its chemical phase composition and the acquisition of a textureless state. In workpieces with a heterogeneous initial structure, for example, consisting of a mixture of large and small grains, in addition to the indicated processes during SPD, the structure is leveled as a result of grinding of large grains.

For the implementation of SPD, in addition to small efforts, three conditions are necessary: the presence of a structure capable of SPD, corresponding to temperature and strain rate. Such conditions with non-contact deformation of the rolled part are observed:

- the initial billet has a structure capable of SPD (moreover, as a result of local forming deformation, the structure in the rolled part becomes finer-grained and / or homogeneous and this increases its ability to SPD);

- the temperature conditions provide regulation (maintenance) in the rolled part of the temperature within the temperature range of the superplasticity of the alloy (the specific superplasticity interval depends on the alloy and its structure; in the general case, it is limited by homological temperatures (0.4-0.85) T _pl , where T _pl - melting point);

- high-speed conditions of deformation of the rolled part, while maintaining the temperature in it in the specified interval, provide control of the speed of deformation during rolling. Although the rate of non-contact deformation of the rolled part differs from the speed of deformation during rolling of the peripheral part due to internal friction, but at the same time, due to the law of conservation of momentum, it corresponds to a wide speed range of SPD.

It was previously noted that the regulation of the strain rate during rolling, its increase or decrease is carried out by the corresponding changes in the values of the feed rollers and the workpiece. The framework for varying feed values is determined by calculation or by experimental data. In particular, it is shown below that a certain selection of the initial dimensions of the peripheral part provides non-contact deformation of the rolled part in billets with a given initial structure at a rate corresponding to superplasticity conditions if the billet is rolled with feeds characteristic of typical equipment.

Non-contact deformation can be carried out by torsion, torsion and stretching or only by stretching. Torsion occurs when rolling is carried out either by two pairs of rollers located at different diameters and having pairwise different speeds of rotation, or by rollers located on the same diameter but rotating at different speeds, or by rollers and pins rotating at different speeds. In all cases, the difference in the rotational speeds of these tools provides a shift in planes orthogonal to the axis of rotation of the workpiece.

Torsion and tension occur during rolling of the workpieces by rollers, when the latter are given higher values of radial feeds. In this case, the fixation of the central part is carried out by pins. Tension occurs when rolling discs with a thin web of blanks with a relatively uniform structure, when the blank is fixed on the mandrel with the possibility of rotation relative to it. Stretching also takes place when rolling is carried out by means of rollers alone, for example three pairs of rollers located at an angle of 120 ° relative to each other, and also symmetrically with respect to the plane containing the axis of the workpiece, and at equal distances from the center of the workpiece. Increasing the uniformity of the structure of the proposed method is due to the accumulation of large deformations in the material and relaxation of residual stresses. First, the deformation in the material of the rolled part accumulates during its formation, and then non-contact deformation is added to it.

Moreover, the non-contact deformation of the rolled part throughout the entire rolling process is combined with the local formation of the following new sections of the rolled part, which, upon completion of the formation, are also involved in non-contact superplastic deformation.

The result from the beneficial use of non-contact superplastic deformation in the considered method is superior to the result achieved in the known processing methods in which SPD is used to improve the structure in large-sized blanks [4]. Although SPD provides a more uniform distribution of deformation in the bulk of the material compared to other types of deformation, it is not possible to effectively use this property in known methods. This is prevented by the heterogeneity of the initial structure in large workpieces and other factors, for example friction, leading to the formation of localization zones of deformation, where the structure acquires uniformity, and stagnant zones where the structure does not change. To align the structure in the workpiece, comprehensive forging is used, during which new zones of deformation localization are formed, and, thereby, the volume of the material with a uniform structure expands. The main advantage of comprehensive forging is the non-uniformity of deformation, due to which the uniformity of the structure increases, the main disadvantage is the high complexity.

Non-contact SPD of the rolled part is substantially nonmonotonic. In the case of stretching of the rolled part under the influence of radially directed components of the rolling force, the nonmonotonicity is determined by the frequency of change in the direction of action of these forces due to the rotation of the workpiece relative to the rollers. The torsion of the rolled part, which occurs under the influence of moments of forces arising on it in the rolled and central parts, is nonmonotonic in nature of this deformation. Moreover, the torsion of the rolled part under conditions of superplasticity is most effective for increasing the uniformity of the structure. In this case, the strain energy is not spent on the formation of a new macroscopic surface, since the dimensions of the rolled part during torsion do not change. Therefore, most of the strain energy goes to the formation of internal surfaces in the material - grain boundaries, i.e. on grinding and leveling the structure. In addition, the torsion of the rolled part is the most characteristic type of non-contact deformation.

In view of the foregoing, for rolling according to the proposed method can be used blanks made by traditional technologies. The complexity of production and the cost of such blanks are significantly lower than blanks obtained by special methods [2].

The proposed method, in contrast to the prototype, allows to obtain parts with a uniform structure from such blanks through the use of non-contact deformation. The proposed method is also effective for preforms made by powder metallurgy methods. Intensive SPD is known to significantly increase the mechanical properties of powder alloys.

For rolling according to the proposed method, it is possible to use billets with submicro- and nanocrystalline grains (average grain size less than 1 μm). Obtaining such blanks is a developing field of technology. Its promise is due not only to the fact that billets with dispersed grains can significantly expand the temperature and speed range of rolling under SPD conditions, but also to the aforementioned increase in the structure homogeneity due to the equalization of chemical and phase compositions, the acquisition of a textureless state, and the complete removal of deformation stresses.

The considered new methods of the method in conjunction with the known methods are necessary and sufficient to solve the tasks. In particular, the uniformity of the structure provided by non-contact SPD is inherited after heat treatment, giving the parts high and isotropic mechanical properties.

Consider the essence of the invention in its further development.

The regulation of the strain rate during rolling and the temperature in the rolled part is performed taking into account the initial structure of the workpiece. The coarser the initial structure of the material, the greater the magnitude and time required for the accumulation of deformation to transform coarse grains into equiaxed fine grains. This is facilitated by reduced rates and elevated deformation temperatures. In billets with a finer-grained initial structure, an increase in its uniformity is achieved with lower degrees of deformation and for shorter processing time, therefore it is advisable to roll them with higher deformation rates, and, therefore, with higher productivity and maintain a lower temperature in the rolled part.

Maintaining a higher temperature in the rolled part compared with the rolling temperature is achieved, for example, by such a technique as rolling by cooled rollers. The expediency of this technique is due not only to providing more intensive non-contact deformation in the rolled part, but also to increasing the tool life.

The temperature of the rolled part can be lowered by a refrigerant, for example, air circulating in the channels made in pins, or supplied to the rolled part from the outlet openings of the channels made in the rollers.

An increase or decrease in the thickness of the peripheral part accordingly reduces or increases the outer diameter of the initial workpiece, because its sizes are chosen taking into account the law of conservation of volume. In the first case, due to an increase in the force and the degree of deformation of the peripheral part, the speed and the degree of non-contact deformation of the rolled part increase, and in the second they decrease. For preforms with a prepared structure, manufactured by an industrial method, experimentally revealed the aspect ratio of the peripheral part, the keeping of which ensures that non-contact deformation of the rolled part under temperature and speed conditions of superplasticity during rolling on standard equipment and maintaining the required temperature in the rolled part leads to improvement of the structure.

The dimensions of the peripheral part for billets of two-phase titanium alloys are recommended to be selected from the following ratios: 1.4≤D _n / D _in ≤1.8, where D _n is the outer, and D _in is the inner diameters of the peripheral part, as well as 0.4≤ ε ₀ = (Н _о -h _p ) / Н _о ≤0.7, where ε ₀ is the compression (degree of deformation) of the peripheral part in thickness, and Н _о and h _p are the initial thickness of the peripheral part and web, respectively. The indicated ratios are valid for blanks with different shapes: shaped, with undercuts for introducing rollers, which are formed in the process of stamping, as well as blanks in the form of washers, which are obtained by upsetting by flat strikers. Making blanks in the form of washers is less time-consuming than stamped shaped blanks. The inner diameter of the peripheral part in the washer is obtained before rolling by introducing rollers of diameter D _{into it} , which increases the manufacturing time of the part and the material consumption, therefore the washers are used for the manufacture of small batches of parts.

The dimensions of the peripheral part for billets of heat-resistant nickel alloys with a fine-grained initial structure, due to the increased rolling forces, it is recommended to choose from the following ratios: 1.3≤D _n / D _in ≤1.7, where D _n is external, and D _in is internal the diameters of the peripheral part, as well as 0.4≤ε = (Н _о -h _п ) / Н _о ≤0.7, where ε ₀ is the compression (degree of deformation) of the peripheral part in thickness. H _about and h _p - respectively, the initial thickness of the peripheral and rolled parts. Although the method of choosing the dimensions of the workpiece is based on empirical knowledge of the results of previous rolling, nevertheless, it is convenient for practical use in serial production;

The list of figures illustrating the invention

Figure 1 presents a diagram of a rolling disk from a curly blank. Figure 2 presents a diagram of the rolling of a disk from a flat workpiece: a - the position of the rollers before introducing them into the workpiece; b - during rolling. Figure 3 shows the structure of a rolled disk of VT18U alloy. Figure 4 shows the structure of a rolled disc made of VT9 alloy. Figure 5 presents a curly blank for rolling discs.

Figure 1 illustrates the most common scheme for rolling disks of heat-resistant alloys using pins and rollers. Figure 1 shows: 1 - rolled stock, 2 and 3 - pintles, 4, 5, 6, 7 - rollers with a combined form of the working part. The arrows indicate the direction of movement of the tool and the workpiece.

Figure 2 shows: 8 - rolled billet, 9 and 10 - rollers with a combined form of the working part, 11 and 12 - rollers with a conical working part. The fixation unit of the workpiece in figure 2 is not shown.

As examples, methods of manufacturing disks with a diameter of 450-800 mm, used in gas turbine engines, from blanks, the initial diameters of which were 1.5-2 times smaller, are considered.

As a rule, disks have a central part - a hub. The deformation of the hub with pins is used to create a developed contact surface of the clutch, which ensures the fixation of the workpiece to bring it with pins in rotation during rolling.

The disks also have a web and a rim formed by rolling under conditions of superplasticity. In this case, the peripheral part of the workpiece, already compressed by the rollers to a predetermined thickness, becomes the blade of the disk, and the rim - “the remainder of the peripheral part that is not used up for manufacturing the blade as a result of its displacement along the radius without a significant change in the original thickness”. In this regard, in relation to the disks, the rolled part is the web formed at this moment, therefore, when describing the examples, instead of the term “rolled part of the blank”, the term “disk web” is used.

The method does not exclude the possibility of increasing the uniformity of the structure and mechanical properties in the hub and rim. However, the techniques used to level the structure and improve properties throughout the disk are beyond the scope of this method and are not considered in the examples below.

The examples do not exhaust all possible specific options for the practical implementation of the proposed method for the manufacture of axisymmetric parts, as well as the materials used for this. In addition to the disks, the proposed method also makes it possible to manufacture other products having a central and roller-rolled parts, for example, bowl-type parts. In all examples, alloys exhibiting the ability to SPD are given. This ability is characterized by the fact that during deformation under temperature-speed conditions of superplasticity they exhibit a large uniform elongation to failure, low flow stress, high sensitivity of the flow stress to the strain rate, and also, as a result of SPD, a uniform fine-grained structure is formed in them.

The information given in the examples about the equipment used, such as the SRD800 disk rolling mill (not shown), confirms the applicability of the method on an industrial scale.

The deformation, including non-contact, of the workpieces intended for the manufacture of critical parts is controlled.

Modern technical means make it possible to determine the value of the twist angle directly during rolling. For this purpose, labels in the form of a coating are applied onto the cylindrical surface of the workpiece that is not rolled around by rollers, the emission spectrum of which in the heated state differs from the spectrum of the workpiece material. The rotation period of such marks is determined by means of optoelectronic devices, for example a pyrometer. Further, it is used to determine the twist angle, comparing with the rotation period of the central part together with the pins. The twist angle corresponds to the degree of shear deformation of the rolled part. During torsion in the vicinity of a certain radius R _{i, the} material in the rolled part moves with an angular velocity ω _i = 2π / T _i , where T _i is the period of rotation of the material at a radius R _i , and in the vicinity of a radius R _{i + 1} - with an angular speed ω _{i +1} = 2π / T _{i + 1} , where T _{i + 1} is the period of rotation of the material at a radius R _{i + 1} . At a distance ΔR = R _{i + 1} - R _{i, the} material undergoes a shear equal to the twist angle during rolling T _p

γ = | ω _{i + 1} -ω _i | T _p = ΔωT _p = 2πT _p | 1 / T _{i + 1} -1 / T _i |

Twisting the rolled part may change direction. This is caused by the presence of advance zones and lagging of the material flow in the deformation zone, a change in the conditions for matching the rotation of the rollers and the workpiece, voltage fluctuations in the power supply network, and other factors. In this case, the deformation is determined by the sum of the twist angles.

The norm of the twist angle (degree of shear strain) is determined by the results of the previous successful rolling of the disk or when testing a sample subjected to torsion under equivalent rolling conditions of deformation. In the absence of technical means for determining the twist angle of the rolled part during deformation, the twist angle can be detected after rolling by natural marks that appear on the surface of the rolled part. Natural marks are spiral grooves with a depth of ~ 0.1 mm. When heated, the surface of the turned workpiece is oxidized, forming, for example, in titanium alloys, a low-plastic alpha layer. As a result of the relative shift of the material, the oxidized layer cracks to form these grooves.

Modern optoelectronic devices also make it possible to evaluate the deformation of the rolled part when it is stretched. In this case, the change in position on the photosensitive sensor of the reflected rays is determined when scanning the surface of the rolled part of the direct laser beam. The change in the positions of the reflected rays occurs due to the removal of the surface of the rolled part from the light source due to its thinning under tension.

The information of the aforementioned optoelectronic devices is processed, demonstrated and used by the rolling control of a technological computer. If the thinning of the rolled part leads to a decrease in thickness to a size close to the maximum necessary, then the deformation rate is reduced mainly by reducing the radial feed of the rollers. With excessive twisting of the rolled part, the circumferential feed of the workpiece is reduced predominantly.

Example 1. At the mill SRD800 rolled disks for gas turbine engines from figured blanks, which were manufactured at a metallurgical plant using standard technology from pseudo-α-titanium alloy VT18U {Chemical composition of the alloy, in% by weight: (6.2-7.3) Al; (2.0-3.0) Sn; (3.5-4.5) Zr; (0.4-1.0) Mo; (0.5-1.5) Nb, the rest is Ti.} In the initial state, the average size of β-transformed grains was ~ 800 μm.

Before heating the billet for rolling, artificial marks were applied to the cylindrical surface of its peripheral part (not rolled by rollers) in the form of a coating having a radiation spectrum different from the billet

Before rolling, the central part of the workpiece was fixed with pins (Fig. 1). Then, by means of the pines, they were brought into rotation, thereby setting the workpiece to the circumferential feed. Local shaping of the peripheral part by rolling was performed by rollers. In this case, two pairs of rollers were used, each of which rotated around its own axis and moved along the path in accordance with the contour of the part by means of radial and axial feeds.

Rolling was carried out with temperature and strain rate control in the temperature-speed range of superplasticity. The rolling temperature in the rolled part was maintained almost the same due to the fact that the rolling was performed in a furnace, which (not shown in the furnace), was heated to a temperature equal to (985 ± 15) ° С. In relative values, this temperature is (T _pp -35) ° C or ~ 0.6 T _pl and lies in the temperature range of the SPD of titanium alloys, usually limited by the values [(T _pp -20) - (T _pp -50 )] ° C, where T _pl is the melting point, T _pp is the temperature of the polymorphic transformation.

The control of the strain rate during rolling was carried out by means of a mill control system (not shown in FIG.), Which supports the given feeds of the rollers and the workpiece. The feeds were set to values that ensure the strain rate during rolling, corresponding to the SPD speed conditions. In particular, the workpiece was rotated with an angular velocity ω = 2πn / 60≈10 ^-1 s ^-1 , where n is the number of revolutions, n = 1 rpm. At this speed of rotation of the workpiece, the circumferential feed was V _o = R _z ω = R _z 2πn / 60≈ (12-25) mm / min, where R _z is the current rolling radius. The radial feed was increased from 2.5 mm / min at the beginning of rolling to 5 mm / min at the end of rolling, and the axial feed was kept at 1 mm / min during the introduction period, and then reduced to zero. At these feeds, the average strain rate during rolling was ξ ~ (1-2) × 10 ^-2 s ^-1 .

Maintaining the indicated rate of deformation during rolling, as well as the temperature in the rolled sheet, equal to (without taking into account random fluctuations) the temperature of deformation during rolling and in the furnace, the local shaping was combined with non-contact deformation of the rolled part under temperature and superplasticity conditions. At the above feed rates, the web was torsionally.

Non-contact deformation was controlled by the angle of twisting of the canvas by means of an automatic pyrometer. A pyrometer through a special hole made in the furnace wall recorded the period of rotation of the artificial marks applied to the rim of the workpiece in the form of a coating having a radiation spectrum different from the workpiece. The signals from the pyrometer and from the pinole rotation speed sensor and the central part of the workpiece were sent to a technological computer, which calculated the twist angle, the degree of deformation, and its time derivative, the deformation rate. The twist angle was ~ 0.6 rad, the corresponding angle was also deformation of the canvas by shear. The average strain rate was ~ 5 × 10 ^-4 s ^-1 . In addition, after rolling and cooling, the twist angle of the web was measured along spiral lines formed on the surface of the web. The discrepancy in the results of measurements of the twist angle by the indicated methods was small, within 10%.

Measurement of disk sizes showed their compliance with the requirements of the drawing. Metallographic studies revealed the effect of non-contact deformation on the structure of the disk. Studies have shown that the most uniform fine-grained structure has formed in the disk web (central position in figure 3). In the rim (left position in Fig. 3), the structure changed to a lesser extent, acquired the so-called “basket weaving” type and corresponded to 3-4 points and type. In the central part of the disk - the hub (the right position in Fig. 3), the structure practically did not change in comparison with the workpiece, since this part was deformed by pins with a small, necessary only for fixation, compression of ~ 1%. The degree of deformation of the rim and the web during their local shaping differed slightly: - 0.75 and 0.7. However, significantly different structural changes in the rolled web and the rim clearly demonstrate that the actual degree of deformation in the web was much greater than in the rim. The accumulation of greater deformation in the fabric was ensured by non-contact torsional deformation, which led to the formation of a uniform fine-grained structure with equiaxed grains less than 10 microns in the fabric. A qualitative assessment of the total degree of superplastic deformation of the rolled sheet from the structural changes that have occurred showed that a strain of ~ 1.3 was accumulated in it. This conclusion is consistent with the results of a similar transformation of the structure in this alloy, observed as a result of its comprehensive forging in the SPD mode.

A number of rolled discs were heat-treated using the first annealing for 30 minutes at a temperature above T _pp at (15-20) ° С with cooling in air and the second annealing at a temperature of 940 ° with cooling in air. Heat treatment led to grain growth and alignment of the structure in the hub, web and rim. The mechanical properties of the samples cut from these parts corresponded to the required technical specifications. Moreover, the mechanical properties of the samples cut from the canvas were 5-7% higher than from the rest of the parts and were stable.

The standard method was used to measure internal stresses in the disk. The measurement results revealed the presence in the hub area of small compressive stresses of ~ 30-50 MPa, the origin of which is due to thermal and mechanical treatments. Tensile stresses in the disk blade are not fixed. Measurement of the depth of the riveted layer showed that it is ~ 30-40 μm, the degree of hardening is not more than 14-17%.

All voltages were small and corresponded to the standards imposed on such products.

Two discs were used for comparative ultrasonic testing. Prior to this, grains were pre-enlarged in one disk by heat treatment to a size of ~ 600 μm, and artificial defects were made in both disks in the form of holes with a diameter of less than 1 mm. In ultrasonic testing of the blade web with a fine-grained structure formed as a result of non-contact SPD torsion, the ratio of the level of the useful sound signal to the noise level was many times greater than in its rim, in which the structure had less uniformity, and also in comparison with the heat-treated disc, in which the structure was coarse-grained. The high level of the useful signal in a homogeneous fine-grained structure formed in the canvas as a result of intense non-contact SPD made it easy to detect the presence of introduced defects in it.

Example 2. At the mill SRD800 a disk was made with a variable web thickness and a rim of two-phase VT9 titanium alloy. {The chemical composition of the alloy, in% by weight: (5.8-7.0) Al; (0.8-2.5) Zr; (2.8-3.8) Mo; (0.2-0.35) Si; the rest is titanium.} The workpiece was obtained by comprehensive forging in isothermal conditions. The macro- and microstructure of the alloy in the preform was fine-grained, with an average grain size of ~ 10-12 μm.

A preliminary calculation showed that the degree of deformation of a thick-walled part of the web during shaping by rollers is ~ 0.4, and that of a thin-walled part is ~ 0.7. It is known from experience that in order to obtain a part with a homogeneous structure from a workpiece with the indicated coarsened structure, nonmonotonic deformation with a degree of ~ (0.9-1.0) is required. Hence, it was found that for a uniform distribution of deformation and the formation of a homogeneous structure in a rolled sheet, the degree of non-contact deformation in its thick section should be ~ (0.5-0.6), and in the thin section ~ (0.2-0.3).

Before heating the billet for rolling, artificial marks were applied to the cylindrical surface of its peripheral part (not rolled in by rollers) in the form of a coating having a radiation spectrum different from the billet. The central part of the workpiece was fixed with pins and through them brought into rotation.

Rolling was carried out with temperature and strain rate control in the temperature-speed range of superplasticity. The temperature in the billet was maintained equal to 950 ° C, which is optimal for the SPD of this alloy (by means of a working furnace). The rolling strain rates were controlled by changes in circumferential and radial feeds. At the same time, along with the pines, the circumferential feed to the workpiece was also set by rollers, the rotation of which was coordinated with the workpiece rotation so that slippage between them was minimal in the contact zone (this condition was fulfilled by automatically adjusting the speed of rotation of the rollers to values that ensure minimal energy consumption in the drives). During the formation of a thick-walled part of the web, the workpiece was rotated at a speed of 5 rpm. The radial feed was equal to 5 mm / min. An axial feed of 2 mm / rev was maintained during the introduction period and then reduced to zero. The deformation rate during rolling with the indicated feeds was ~ 10 ^-1 s ^-1 .

Maintaining the indicated rate of deformation during rolling and the temperature in the fabric, they ensured that local shaping was combined with non-contact deformation of the thick-walled part of the fabric by torsion under temperature and speed conditions of superplasticity. The twist angle of the sheet γ was ~ 0.6 rad, respectively, the degree of shear deformation was ~ 0.6. The non-contact strain rate of this part of the web was ~ 3 × 10 ⁻³ s ⁻¹ .

When rolling the transition to the thin-walled part of the web, the circumferential feed was reduced by five times, the radial feed was halved, and the axial feed was chosen to be 1 mm / min, and then reduced to zero. With such feeds, in addition to twisting (~ 0.35 rad), the thin-walled part was subjected to non-contact tensile deformation, which led to an acceptable thinning of the canvas, taking into account the designated allowance (~ 20%). The rate of non-contact deformation of the thin-walled part of the web was ~ 10 ^-4 s ^-1 .

The degree of deformation of the rolled sheet under tension was controlled by means of a remote optoelectronic device. It recorded a change in position on a photosensitive sensor (line) of rays reflected from the surface of the web when scanning a direct laser beam along this surface. Special holes were made for input and output of rays in the furnace, and heat-protected fibers were used. Information from an optoelectronic device was also processed by a technological computer that calculated the deformation (thinning) of the web in absolute and relative values, in particular: Δh = hh _p and Δh / h _f , where h is the thickness of the web specified when rolling by rollers, and h _f - the thickness of the web actually obtained as a result of tensile deformation.

Subsequent studies revealed that, in comparison with the initial macro- and microstructure of the workpiece, the structure in the disk sheet (Fig. 4) acquired high uniformity and fine grain.

Ultrasonic inspection of the disk showed no defects in it. The mechanical properties of the rolled disk after standard heat treatment, performed using heating in the first stage of annealing to a temperature below the polymorphic transformation temperature of the alloy, satisfied the upper level of technical requirements.

Example 3. Made the same as in example 1, a disk of titanium alloy VT18U. Unlike example 1:

- used a workpiece with a mixed structure, which was obtained as a result of multi-junction comprehensive forging in the (α + β) region, performed with decreasing temperature. Over 50% of the volume of grain stocks acquired a globular shape and a submicrocrystalline size of ~ (0.7-0.9) microns. In less deformed zones, the structure was globular, ~ 2-5 microns, but areas with a globular lamellar structure were also observed;

- temperature-speed rolling conditions were regulated in the range of (850-900) ° C and (1-2) × 10 ° s ^-1 ;

- the temperature in the rolled part was maintained within the range of (750-800) ° C by its cooling by means of air circulating in the channels made in pins and air supplied to the surface of the rolled part from the outlet openings of the channels made in the rollers.

By controlling the rate of deformation during rolling, as well as the temperature in the sheet, within the limits corresponding to the temperature and speed range of superplasticity of the alloy, the local shaping was combined with non-contact deformation of the rolled part by torsion under temperature and speed conditions of superplasticity. The degree of shear strain was ~ 0.9. The average rate of non-contact deformation was ~ 10 ⁻³ s ⁻¹ .

Studies of the structure and properties showed that the microstructure in the sheet acquired high uniformity and texturelessness, the average grain size in the rolled sheet was ~ 2 μm. After heat treatment, the mechanical properties of samples cut from a disk web were more stable and have a higher level of properties compared to samples cut from a rim in which the structure was worked out to a lesser extent during rolling.

Example 4. At the mill SRD800 a disk was made of high-alloy heat-resistant nickel alloy obtained by powder metallurgy. The alloy contained about 50% of the intermetallic γ 'phase, part of which was relatively large ~ (0.3-1.5) microns, and the other was dispersed, less than 0.1 microns. The initial preform structure had an average matrix grain size of ~ 20 μm.

For rolling, we used a shaped blank having a central and peripheral part, separated by undercuts to introduce rollers in front of the peripheral part. The outer D _n and inner D _{in the} diameters of the peripheral part were selected from the condition D _n / D _g = 1.5, and the thickness from the condition ε _o = (Н _о -h _п ) / H _o = 0.6, where ε _o - the relative compression of the peripheral part by rollers in thickness, N _about and h _p - respectively, the thickness of the peripheral part and the rolled part.

Rolling was carried out with temperature and strain rate control in the temperature-speed range of superplasticity. The temperature in the billet was maintained equal to the temperature of the furnace heated to (1100-1120) ° С, while rolling was performed by cooled rollers, which reduced the temperature of the peripheral part in the local deformation zone to (1050 -1070) ° С. The deformation rate during rolling was maintained in the range of (5-8) × 10 ^-3 s ^-1 The temperature in the web was maintained equal to the temperature of the furnace, i.e. in the range of (1100-1120) ° C.

By adjusting the deformation rate during rolling and the temperature in the sheet at the indicated intervals, they ensured that the local formation of the disk is combined with non-contact deformation of the sheet by torsion under temperature and speed conditions of superplasticity. The degree of shear deformation was ~ 0.8, and the average rate of non-contact deformation of the web was ~ 10 ^-4 s ^-1 .

After rolling, the structure in the sheet was crushed and acquired uniformity. In particular, the average grain size of the matrix (γ'-phase) was 5 μm, almost the entire intermetallic γ'-phase was enlarged and acquired a size of 2-3 μm. The uniformity of the chemical composition also increased. The distribution of crystallographic orientations of grains acquired randomness, i.e. There was no texture.

A comparison of the mechanical properties of the samples cut from the disk blade and from the initial billet, heat-treated according to the same conditions, showed that the intensive deformation study of the structure of the powder alloy under superplasticity conditions, which occurred as a result of local shaping and non-contact deformation of the sheet during rolling, provided the alloy with a higher ( ~ 10%) complex of properties compared with the initial state.

Example 5. At the mill SRD800, disks with various diameters from 500 to 800 mm were made of two-phase (α + β) - VT25U titanium alloy. {The chemical composition of the alloy, in% by weight: (6.0-7.0) Al; (1.0-2.5) Sn; (3.0-4.5) Zr; (3.5-4.5) Mo; (0.1-0.25) Si; (0.4-1.5) W; the rest is titanium.} In the initial state, the alloy structure was coarse-grained with a grain size exceeding 20 microns.

For rolling used shaped blanks having a Central and peripheral parts (figure 5). The dimensions of the peripheral part of the blanks were selected based on the recommended ratios between the outer D _n and inner D _in diameters and the ratio ε _о = (Н _о -h _п ) / H _o , where ε _o is the relative compression of the peripheral part by rollers in thickness, But and h _p - respectively, the thickness of the peripheral part and the rolled sheet.

The ratios by which the sizes of the peripheral part were selected are indicated in the table, there are also shown:

- temperature and strain rate during rolling, corresponding to the temperature-speed interval of superplastic deformation of an alloy with a coarse-grained lamellar structure, and the strain rate during rolling was ensured by setting the maximum circumferential and radial feed rates for a given line, and the deformation temperature was kept below the temperature in the furnace due to rolling cooled rollers;

- temperature and speed conditions of superplastic non-contact deformation in the canvas;

- its type and degree;

- the structure formed in the canvas.

Table Stock No. Peripheral aspect ratio Temperature-speed rolling interval Non-contact deformation of the canvas Temperature ° C Speed, s ^-1 Type and degree Formed structure 1 D _n / D _in = 1.8 ε _o = 0.7 (940-960) ° С ~ 10 ^-1 s ^-1 , 970-980 2 × 10 ^-3 Torsion ~ 1.5 and elongation ~ 20% Homogeneous 2 d _n / d _in = 1.8 ε _o = 0.4; 2 × 10 ^-4 Torsion ~ 0.9 Homogeneous 3 d _n / d _in = 1.4 ε _o = 0.7; 10 ^-3 Torsion ~ 1.2. Homogeneous 4 d _n / d _in = 1.4 ε _o = 0, 4 5 × 10 ^-4 Torsion ~ 0.7 Homogeneous

The data presented in the table show that the disk blade obtained from blank No. 1, which had the largest initial dimensions of the peripheral part, which underwent compression during rolling (ε _o = 0.7) and then non-contact deformation, accumulated the greatest torsional and tensile deformation. The blade deformation rolled from billet No. 4, which had the minimum initial dimensions of the peripheral part, subjected to less reduction in height and less non-contact deformation during rolling, acquired minimal deformation.

In all cases, rolling of billets with peripheral dimensions selected in accordance with the indicated ratios, to a greater extent for billets Nos. 1, 3 and slightly less for billets Nos. 2, 4, resulted in a substantial refinement of the initial structure and an increase in its size as a result of accumulation of deformation homogeneity.

Billets were also rolled in which the dimensions of the peripheral part were selected outside the specified frames. When rolling billets, in which the sizes of the peripheral part were selected from the ratios D _n / D _of > 1.8 and / or ε _o > 0.7, localization of non-contact deformation was observed in the areas adjacent to the disk hub with an increase in speed above the upper limit of the interval SPD. The uneven distribution of non-contact torsion deformation, due to insufficient preliminary grinding of the structure in the fabric during shaping, resulted in the rolling of billets with different ratios D _n / D _in which the thickness of the peripheral part was chosen from the condition of small reduction - ε _о <0.4.

After rolling, the disks made from billets Nos. 1–4 were heat treated with heating at the first annealing stage below the polymorphic transformation temperature and subsequent standard annealing. Samples were cut from the disks and tested for mechanical properties and structural studies.

The results showed that in all discs the mechanical properties exceed the level determined by the technical conditions for the respective parts.

Example 6. At the mill SRD800 a disk was made from a workpiece made in the form of a flat washer from a two-phase (α + β) -titanium alloy VT25U. The initial structure in the puck was mixed: globular-lamellar, with an average grain size of 25-30 microns.

The thickness of the washer was selected from the condition of compression of the peripheral part in the axial direction ε _o in accordance with the ratio ε _o = (Н _о -h _п ) / Н _о = 0.7.

Rolling was carried out by two pairs of rollers in accordance with the scheme shown in figure 2. One pair of rollers had a conical working part, and the other a combined one, combining at least a calibrating surface of the web — an end cone and a middle cone inclined to the rolling plane. 2, the rollers also have initial cones, which were not used in the implementation described in this example.

Rolling a flat billet began with the introduction of combined rollers in it so that the ratio between the outer D _n and the inner D _in diameters was 1.8.

When rolling, the combined rollers were moved along a path corresponding to the contour of the part by means of the feeds specified by them. At the same time, at the implementation stage, they displaced the material beyond the middle cone.

The minimum distance between the rollers with the conical working part was set equal to H _about and during rolling they were moved only in the radial direction. As a result, the rollers with a conical working part crimped the material displaced by the combined rollers, providing a rim thickness of H _about .

The local shaping of the peripheral part was carried out with the temperature and strain rate controlled during rolling in the temperature-speed range of superplasticity. The strain rate was ~ 10 ^-1 s ^-1 , the rolling temperature was (960-980) ° С.

Due to the maintenance of the specified strain rate during rolling, as well as the temperature in the sheet equal to the temperature of rolling, a combination of local shaping with non-contact deformation of the sheet by torsion under temperature and speed conditions of superplasticity was ensured. The degree of shear deformation during torsion of the web was ~ 0.9. The average rate of non-contact deformation was ~ 7 × 10 ^-4 s ^-1 .

As a result of rolling, a disk with a uniform fine-grained structure in the sheet corresponding to 1 point and 1 type according to standard scales was obtained. After rolling, the disks were subjected to thermal and mechanical treatments and the mechanical properties were checked. Disk control showed compliance of all its parameters with the requirements of technical conditions.

Example 7. At the mill SRD800 a disk was made with a variable web thickness and a rim of two-phase VT9 titanium alloy. {The chemical composition of the alloy, in% by weight: (5.8-7.0) Al; (0.8-2.5) Zr; (2.8-3.8) Mo; (0.2-0.35) Si; the rest is titanium.} The workpiece was obtained by comprehensive forging in isothermal conditions. The macro- and microstructure of the alloy in the preform was fine-grained, with an average grain size of ~ 10-12 μm.

A preliminary calculation showed that the degree of deformation of a thick-walled part of the web during shaping by rollers is ~ 0.4, and that of a thin-walled part is ~ 0.7. It is known from experience that in order to obtain a part with a homogeneous structure from a workpiece with the indicated coarsened structure, nonmonotonic deformation with a degree of ~ (0.9-1.0) is required. Hence, it was found that for a uniform distribution of deformation and the formation of a homogeneous structure in a rolled sheet, the degree of non-contact deformation in its thick section should be ~ (0.5-0.6), and in the thin section ~ (0.2-0.3).

Before heating the billet for rolling, artificial marks were applied to the cylindrical surface of its peripheral part (not rolled in by rollers) in the form of a coating having a radiation spectrum different from the billet. The central part of the workpiece was fixed with pins and through them brought into rotation.

Rolling was carried out with temperature and strain rate control in the temperature-speed range of superplasticity. The temperature in the billet was maintained equal to 950 ° C, which is optimal for the SPD of this alloy (by means of a working furnace). The rolling strain rates were controlled by changes in circumferential and radial feeds. At the same time, along with the pins, the circumferential feed to the workpiece was also set by rollers, the rotation of which was coordinated with the workpiece rotation so that slippage between them was minimal in the contact zone (this condition was fulfilled by automatically adjusting the speed of rotation of the rollers to values ensuring the minimum energy consumption in the drives). During the formation of a thick-walled part of the web, the workpiece was rotated at a speed of 5 rpm. The radial feed was equal to 5 mm / min. An axial feed of 2 mm / rev was maintained during the introduction period and then reduced to zero. The deformation rate during rolling with the indicated feeds was ~ 10 ^-1 s ^-1 .

Maintaining the indicated rate of deformation during rolling and the temperature in the fabric, they ensured that local shaping was combined with non-contact deformation of the thick-walled part of the fabric by torsion under temperature and speed conditions of superplasticity. The twist angle of the sheet γ was ~ 0.6 rad, respectively, the degree of shear deformation was ~ 0.6. The non-contact strain rate of this part of the web was ~ 3 × 10 ⁻³ s ⁻¹ .

When rolling the transition to the thin-walled part of the web, the circumferential feed was reduced by five times, the radial feed was halved, and the axial feed was chosen to be 1 mm / min, and then reduced to zero. With such feeds, in addition to twisting (~ 0.35 rad), the thin-walled part was subjected to non-contact tensile deformation, which led to an acceptable thinning of the canvas, taking into account the designated allowance (~ 20%). The rate of non-contact deformation of the thin-walled part of the web was ~ 10 ^-4 s ^-1 .

The degree of deformation of the rolled sheet under tension was controlled by means of a remote optoelectronic device. It recorded a change in position on a photosensitive sensor (line) of rays reflected from the surface of the web when scanning a direct laser beam along this surface. Special holes were made for input and output of rays in the furnace, and heat-protected fibers were used. Information from an optoelectronic device was also processed by a technological computer, which calculated the deformation (thinning) of the web in absolute and relative values, in particular Δh = hh _p and Δh / h _f , where h is the thickness of the web specified when rolling by rollers, and h _f - the thickness of the web actually obtained as a result of tensile deformation.

Subsequent studies revealed that, in comparison with the initial macro- and microstructure of the workpiece, the structure in the disk sheet (Fig. 4) acquired high uniformity and fine grain.

Ultrasonic inspection of the disk showed no defects in it. The mechanical properties of the rolled disk after standard heat treatment, performed using heating in the first stage of annealing to a temperature below the polymorphic transformation temperature of the alloy, satisfied the upper level of technical requirements.

Example 8. At the mill SRD800 a disc was made of two-phase VT9 titanium alloy. The workpiece was obtained by comprehensive forging in isothermal conditions. The macro- and microstructure of the alloy in the preform was ultrafine-grained, with an average grain size of ~ 0.5 μm. The presence of such a structure in the alloy ensured an increase in its structural strength by 30–40%, which made it possible to use an alloy with such a structure for manufacturing a disk for the second compressor stage. Due to the relatively high initial uniformity of the structure, rolling of such a disk was performed with the maximum approximation of its size to the final one.

Preliminary calculation showed that the degree of deformation of the web during shaping by rollers will be ~ 0.8. From this it was established that for non-contact deformation by stretching, not exceeding 20% is sufficient for the final alignment of the structure (imparting a textureless state that increases the isotropy of mechanical properties and for removing strain stresses).

The workpiece was fixed on a cylindrical mandrel installed in the hole of the workpiece with the possibility of free rotation of the latter (the scheme of such rolling is not shown in Fig.).

Rolling was carried out by two pairs of drive, opposite rollers. In this case, the workpiece rotated due to the rotation of the rollers.

Rolling was carried out with temperature and strain rate control in the temperature-speed range of superplasticity. The temperature in the billet was maintained equal to 750 ° C, which is optimal for the SPD of this alloy with a SMC structure (by means of a working furnace). The rolling strain rates were controlled by changes in circumferential and radial feeds. The radial feed was equal to 3 mm / min. An axial feed of 2 mm / rev was maintained during the introduction period and then reduced to zero. The deformation rate during rolling with the indicated feeds was ~ 10 ^-1 s ^-1

Maintaining the indicated strain rate during rolling and the temperature in the web, they ensured that local shaping was combined with non-contact web deformation by stretching under temperature and speed conditions of superplasticity. The speed of non-contact deformation of the canvas was ~ 3 × 10 ^-3 s ^-1 .

The degree of deformation of the rolled sheet under tension was controlled by means of a remote optoelectronic device. It recorded a change in position on a photosensitive sensor (line) of rays reflected from the surface of the web when scanning a direct laser beam along this surface. Special holes were made for input and output of rays in the furnace, and heat-protected fibers were used. Information from an optoelectronic device was also processed by a technological computer that calculated the deformation (thinning) of the web in absolute and relative values, in particular Δh = hh _p and Δh / h _f , where h is the thickness of the web specified when rolling by rollers, and h _f - the thickness of the web actually obtained as a result of tensile deformation. The degree of non-contact deformation of the disk by stretching did not exceed 20%, and on average over the canvas was 16%

Subsequent studies revealed that, in comparison with the initial macro- and microstructure of the workpiece, the structure in the disk sheet (Fig. 4) acquired high uniformity due to the obtainment of a textureless state.

Ultrasonic inspection of the disk showed no defects in it. The mechanical properties of the rolled disk after annealing at a temperature not exceeding the operating temperature were characterized by a high level of strength and plastic properties. Moreover, the spread of properties for samples cut in the tangential and radial directions did not exceed 3.5%.

Sources of information

1. A.S. USSR No. 536883, 21 K 1/32, 1975

2. RF patent No. 2119842, B 21 K 1/32, C 22 F 1/10, 1998

3. V.M.Kolmogorov. Mechanics of metal forming. M., Metallurgy, 1986, p. 688.

4. RF patent No. 2134308, C 22 F 1/18, 1999

Claims (10)

1. A method of manufacturing axisymmetric parts from workpieces made of multiphase alloys capable of superplastic deformation, including rolling with temperature and strain rate control during rolling in the temperature-speed range of superplasticity, temperature control in the rolled part of the workpiece, and heat treatment, characterized in that rolling is combined with non-contact superplastic deformation of the rolled part of the billet, which is provided by the choice of strain rate When the rolling temperature and rolled portion of the billet. 2. The method according to claim 1, characterized in that the rolling of the workpieces with the original structure, the average grain size of which is equal to or greater than 20 microns, is carried out, maintaining the strain rate during rolling in the range (10 ^-3 -10 ^-1 ) s ^-1 and the temperature in the rolled part is not lower than the deformation temperature during rolling. 3. The method according to claim 2, characterized in that in the manufacture of disks of two-phase titanium alloys, a curly axisymmetric billet is used having a central and peripheral part, separated by undercuts to introduce rollers in front of the peripheral part, the outer D _n and inner D _{in the} diameters of the peripheral part choose from a ratio of 1.4≤D _n / D _to ≤1.8, and the thickness of H _about from the ratio of 0.4≤ε _about = (N _about -h _p ) / N _about ≤0.7, where ε _o - the relative compression of the peripheral part by rollers in thickness, and h _{p the} thickness of the rolled part. 4. The method according to claim 2, characterized in that in the manufacture of disks of two-phase titanium alloys, a plane axisymmetric billet is used - a washer, the thickness H _about which is chosen from the ratio 0.4≤ε _o = (N _about -h _p ) / N _about ≤0.7, where ε _o is the relative compression of the peripheral part by rollers in thickness, h _p is the thickness of the rolled part, while the inner diameter of the peripheral part D _in is determined taking into account the ratio of 1.4≤D _n / D _in ≤1.8, where D _n - the outer diameter of the peripheral part, and form before rolling by introducing rollers into the workpiece. 5. The method according to claim 2, characterized in that in the manufacture of disks of heat-resistant nickel alloys, a curly axisymmetric billet is used having a central and peripheral part, separated by undercuts to introduce rollers in front of the peripheral part, the outer D _n and inner D _{in the} diameters of the peripheral part choose from the condition 1.3≤D _n / D _to ≤1.7, and the thickness from the condition 0.5≤ε _о = (Н _о -h _п ) / Н _о ≤0.7, where ε _о is the relative compression the peripheral part of the rollers in thickness, N _about and h _p - respectively, the thickness of the peripheral part and the rolled part. 6. The method according to any one of claims 2, 3, 4, 5, characterized in that the rolling is performed by cooled rollers. 7. The method according to claim 1, characterized in that the rolling of the workpieces with the original structure, the average grain size of which is limited to an interval of 1-20 microns, is carried out while maintaining the strain rate during rolling in the interval (10 ^-1 -10 ⁰ ) s ^-1 and the temperature in the rolled part is not higher than the deformation temperature during rolling. 8. The method according to claim 1, characterized in that the rolling of billets with an initial structure, the average grain size of which is less than 1 μm, is carried out, maintaining the strain rate during rolling in the range (10 ⁰ -10 ² ) s ^-1 and the temperature in the rolled parts not higher than the deformation temperature during rolling. 9. The method according to claim 7 or 8, characterized in that the fixation of the workpiece is performed by cooled pins. 10. The method according to claim 7 or 8, characterized in that the rolled part is cooled by air supplied to its surface from the outlet holes of the channels made in the rollers.

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