RU2426618C1 - Method of producing thin-wall shells with periodic large-diameter profile - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming and may be used in producing thin-wall large-diameter shells. Periodic profile is formed by deforming the billet revolving on rotary mandrel by several rolls. Note here that billet with bottom is used arranged on mandrel with clearance making 0.06-0.08 of billet wall thickness to thrust against its bottom. Said periodic profile is made in two or several passes. Deforming in first pass is made with variable degree of deformation on biller end section and, in next passes, on billet start and main sections. Rolls have taper lead-in section, front working and rear conjugated surfaces, and cylindrical collar of its top. Rolls move radially to and from said mandrel, feed magnitude being varied. Mandrel with billet is fed axially opposite the draft direction.

EFFECT: expanded performances.

7 cl, 4 dwg, 2 tbl, 1 ex

Description

с периодическим профилем наружной поверхности в виде чередующихся участков цилиндрической и конической формы различной толщины и углов наклона конусов, например различных тонкостенных оболочек из низкоуглеродистых и легированных сталей, а также алюминиевых сплавов: баллонов, огнетушителей, емкостей для хранения жидкостей.The invention relates to the field of metal forming, namely the manufacture of thin-walled shells of large diameters and lengths with a ratio of diameter to wall thickness

with a periodic profile of the outer surface in the form of alternating sections of cylindrical and conical shapes of various thicknesses and tilt angles of the cones, for example, various thin-walled shells made of low-carbon and alloy steels, as well as aluminum alloys: cylinders, fire extinguishers, and containers for storing liquids.

The most important problems in the production of such shells is the fundamental possibility of their production by rotational drawing with high accuracy and quality of the processed surface.

A known method of rotational drawing of hollow axisymmetric parts / SU 745584, B21H 8/00, B21D 22/14, 07/07/80, /, in which the original workpiece is deformed on a rotating mandrel by several conical rollers in a continuous deformation zone with its separation into several zones, sequentially located along the axis of the mandrel and inclined to it at different angles with increasing angle of inclination from the beginning to the end of the deformation zone. The deformation is carried out with the same degree of deformation and a constant thickness of the treated surface. The method cannot be used for rotational drawing of shells with a variable wall thickness of a periodic profile, because due to the different area of the tapered rollers with the workpiece at different angles of inclination of the working surfaces of the rollers (see figure 1 description) the radial loads on each roller will not be equal , which leads to a radial displacement of the mandrel with the part, loss of stability of the deformation process and a decrease in the accuracy of the manufactured shells.

The closest in technical essence and technical result achieved is patent RU 2106217 C1, B21D 22/16, 03/10/1998, in which the initial workpiece is deformed on a rotating mandrel by several conical rollers in a continuous deformation zone with its division into several zones, arranged in series along the axis of the mandrel and inclined to it at different angles with increasing angle of inclination from the beginning to the end of the deformation zone, and deformation is carried out at equal radial loads on each roller by displacement rollers interacting with each zone, relative to rollers interacting with other zones, in the radial direction by an amount calculated depending on the total strain on the machined area and the geometrical parameters of each roller, while the vertices of the roller cones are located in one plane perpendicular to the axis mandrel rotation. A continuous deformation zone is realized as a result of axial in the drawing direction and radial movement of the rollers on a rotating mandrel that is stationary in the axial direction. The tops of the rollers describe the trajectory of the periodic profile (figure 4). The workpiece on the mandrel is fixed with emphasis in the end stop (figure 4).

This method is adopted by the authors for the prototype.

As can be seen from this technical solution, a periodic profile of the outer surface of the shell (FIG. 4 of the description) is obtained by deforming the workpiece with tapered rollers with different angles of the working surface (FIG. 3 of the description) and offset in the radial direction.

This method is used for rotational drawing of shells with a periodic profile with a diameter of up to 300 mm and a workpiece wall thickness of 5–7 mm.

The reasons that impede the achievement of the indicated technical solution when using the known method adopted by the authors for the prototype include the inability to use the radial displacement of the rollers and different angles of the profile of the working surfaces of the rollers in the manufacture of thin-walled shells with a periodic profile of large diameters (2 ÷ 3 m) and long lengths ( 1 ÷ 3 m) due to the fact that for large sizes and masses (10 ÷ 15 t) of the working tool - mandrels and roller assemblies, the question of the radial displacement of the rollers between themselves is not technically solved th, and the use of rollers with a working profile of a different angle of inclination leads to runout of the mandrel with the shell and to loss of stability of the deformation process in the form of corrugations and folds, as well as to a decrease in the accuracy of the geometric parameters of the resulting shells.

In addition, when rotating hoods of large diameters and large lengths with a continuous deformation zone, it is problematic to ensure the accuracy of geometric dimensions due to the fact that the deformation of the workpiece is carried out at a large distance from the end part of the mandrel mounted on the machine spindle, which leads to runout of the mandrel with the workpiece.

Also, the specificity of the rotational drawing of large-sized shells required a change in the workpiece stop in the mandrel, since with a known pattern of fixing the workpiece with a stop in the end stop (Fig. 4), due to the large axial and radial rolling forces (up to 100 tons), such stops are crushed.

The most important factor in ensuring the stability of the process of rotational drawing of thin-walled shells of large diameter and length with a periodic profile is also the choice of the gap between the workpiece and the mandrel, the development of a special profile of rollers that are not regulated in the known method. In addition, the rotation scheme of the known method with axially and radially moving rollers with a rotating mandrel that is not axially moving and horizontally oriented is not acceptable when rotating thin-walled shells of large sizes due to the influence of large masses of the tool (mandrel, roller assemblies ), with great inertia.

Thus, the objective of the known technical solution adopted by the applicants for the prototype was to create a method of rotational drawing of shells with a periodic profile by rollers with different angles of inclination of the profile of the working surfaces and radially displaced to each other in order to expand technological capabilities.

Common features with the method proposed by the applicants is the deformation of the workpiece on a rotating mandrel with several rollers.

Unlike the prototype, in the method proposed by the applicants for the rotational drawing of thin-walled shells of large diameter with a periodic profile, a workpiece with a bottom is used, which is installed on a mandrel with a gap of 0.06 ÷ 0.08 of the wall thickness of the workpiece with an emphasis in its bottom, and the process of forming a periodic profile is carried out for two or more transitions with a variable degree of deformation, at the first transition at the end section of the workpiece, at subsequent transitions - at the initial section and its main part, the rollers being the same profiles made with a conical entry section, a front working surface and a rear surface mating with each other, and with a cylindrical girdle at the top, are moved only in the radial direction to and from the mandrel with different feed sizes, and the mandrel is moved with the workpiece in the axial direction, opposite to the drawing direction.

In special cases, that is, in specific forms of execution, the invention is characterized by the following features:

- the radial feed of the rollers when they exit the end sections of the workpiece is chosen 1.5 ÷ 2.5 times greater than the radial feed in the previous sections;

- initially, with a lower degree of deformation, a section of the profile with a larger wall thickness is formed, and then with a greater degree of deformation, a section with a smaller wall thickness and then alternating sections in the same sequence;

- the ratio of the degrees of deformation during deformation of the sections of the periodic profile of larger and smaller wall thicknesses is set within 0.6 ÷ 0.8;

- the rollers are installed in the same position in the radial and axial directions, and the profile of the rollers is performed at the entrance section with an angle of 3 ÷ 7 degrees, on the front surface with an angle of 25 ÷ 35 degrees, on the rear surface with an angle of 7 ÷ 15 degrees, s a cylindrical girdle on top equal to 0.3 ÷ 0.5 the thickness of the wall of the workpiece;

- the lead-in section, the front and rear surfaces and the cylindrical belt profile of the rollers are mated in a radius equal to 0.25 ÷ 0.55 of the wall thickness of the workpiece;

- on the end surfaces of the rollers, thrust annular grooves are made with a depth of 0.3 ÷ 0.7 of the wall thickness of the workpiece and with a radius of profile equal to 2 ÷ 3 of the wall thickness of the workpiece and a diameter of 0.6 ÷ 0.8 of the diameter of the roller.

It is this that allows us to conclude that there is a causal relationship between the totality of the essential features of the claimed technical solution and the achieved technical result.

The objective of the invention is to provide a method for the manufacture of thin-walled shells of large diameter and length with a periodic profile of a rotational hood with high stability of the forming process, providing high accuracy and quality of the processed surface.

The specified technical result in the implementation of the invention is achieved by the fact that in the known method, including the deformation of the workpiece on a rotating mandrel with several rollers, the feature is that they use a workpiece with a bottom, which is installed on the mandrel with a gap of 0.06 ÷ 0.08 of the wall thickness of the workpiece with emphasis on its bottom, and the process of forming a periodic profile is carried out in two or more transitions with a variable degree of deformation, at the first transition at the end section of the workpiece, at subsequent exits - in the initial section and its main part, while rollers of the same profile, made with a tapered lead-in section, a front working surface and a rear surface mating with each other, and with a cylindrical belt at the top, are moved only in the radial direction to and from the mandrel with different feed sizes, and the mandrel is moved with the workpiece in the axial direction opposite to the drawing direction.

The new set of operations, as well as the presence of relations between them, allow due to:

- use of the workpiece with a bottom with an emphasis on its bottom - to increase the stability of the deformation process, since with large diameters of the workpiece and, therefore, large rolling forces (axial and radial forces reach 100 tons), the support surface of the workpiece bottom is much larger than the end support surface of known technical solutions, which guarantees the stability of the deformation process as a result of elimination of crushing of the end stop of the workpiece;

, такая величина зазора создает плотную посадку заготовки на оправке, что обеспечивает точность размеров обработанных оболочек из-за уменьшения явления «раскатки» - увеличения диаметральных размеров; необходимо заметить, что зазор 0,06÷0,08 толщины стенки является оптимальным с точки зрения устойчивости процесса деформирования, так при меньшем зазоре (меньше 0,06 толщины стенки) затруднена установка заготовки на оправку из-за появления поперечных гофр при давлении прижима на дно заготовки; более 0,08 толщины стенки возрастают диаметральные размеры заготовки при деформировании из-за явления «раскатки» с появлением поперечно-винтовых и продольных гофр;- installation of the workpiece on the mandrel with a gap of 0.06 ÷ 0.08 of the wall thickness of the workpiece to ensure high stability of the deformation process as a result of the fact that with a large diameter and thin wall of the workpiece, with the ratio of the diameter and wall thickness of the workpiece

, such a gap creates a tight fit of the workpiece on the mandrel, which ensures the accuracy of the dimensions of the processed shells due to the reduction of the phenomenon of “rolling” - an increase in the diametrical dimensions; it should be noted that the gap of 0.06 ÷ 0.08 of the wall thickness is optimal from the point of view of stability of the deformation process, so with a smaller gap (less than 0.06 of the wall thickness) it is difficult to install the workpiece on the mandrel due to the appearance of transverse corrugations at a pressure of bottom of the workpiece; more than 0.08 of the wall thickness, the diameters of the workpiece increase during deformation due to the phenomenon of “rolling” with the advent of transverse helical and longitudinal corrugations;

- shaping the periodic profile of the workpiece for two or more transitions, at the first transition at the end section of the workpiece, at subsequent transitions - at the initial section and its main part - divide the deformation along the length of the workpiece, since the first transition is deformed at the end section, and at subsequent transitions - at the initial and its main sections of the workpiece, which increases the stability of the forming process as a result of the banding effect on the end section of the workpiece, which is in tight contact to the inner surface of the workpiece at the end of the workpiece near the machine spindle, where the mandrel runs out the least, and during shaping at the second and subsequent transitions, the banding effect of the end part is preserved at the initial and main sections, which increases the accuracy of the geometric dimensions also at the initial and main sections of the workpiece;

- shaping a periodic profile with a variable degree of deformation - get a variable wall thickness of a periodic profile;

- shaping the workpiece with rollers with the same profile - to ensure equal radial and axial forces of rolling, as a result, the runout of the mandrel is reduced, which in turn increases the stability of the process of forming and the accuracy of the size of the resulting shells;

- shaping the workpiece with rollers with a conical entry section, a front working surface and a rear surface mating with each other and with a cylindrical belt at the top - to ensure high stability of the forming process, since the entry surface of the profile prevents the formation of an influx in front of the front surface, the front surface deforms the metal layer, a cylindrical girdle and a back surface smooths the combs of the metal and ensures the cleanliness of the treated surface;

- forming the workpiece with rollers moving only in the radial direction to the mandrel and from it with different feed sizes when moving the mandrel with the workpiece in the axial direction opposite to the drawing direction - to provide the possibility of obtaining a periodic profile of various thicknesses with a variable degree of deformation, since with this deformation scheme (direct rotation hood), the radial movement of the rollers with different values of the radial feed when the axial movement of the mandrel with the workpiece with a constant led Due to the axial feed, a periodic trajectory of the deformation zones is provided in the form of periodically alternating trapezoidal sections of the profile.

The features characterizing the invention in specific execution formats allow, in particular, due to:

- selection of the radial feed of the rollers when they exit the end sections of the workpiece, 1.5 ÷ 2.5 times greater than the radial feed in the previous sections - to increase the stability of the process of forming on the end sections at all transitions of the rotational hood as a result of stopping the "edge" effect, which consists in the expansion and curvature of the edge - end sections of the workpiece due to the imbalance of stresses in the deformation zones at the edge or end of the workpiece, which is typical for plastic deformation of thin-walled cylinders physical blanks; thus, when the rollers exit quickly from the end sections — with a feed 1.5–2.5 times greater than the radial feed in the previous sections, the “edge” effect is not detected, it is detected with a radial feed less than 1.5 times, and if the output of the rollers is too fast, more than 2.5 times due to the large mass of the roller assemblies and their inertia, too fast the rollers can lead to an accident - destruction of bearings and rollers;

- first, forming with a lower degree of deformation a section of a profile with a larger wall thickness, and then with a greater degree of deformation, a section with a smaller wall thickness, and then, alternating sections in the same sequence, to ensure high stability of the forming process, since such a pattern of formation is first with a small degree of deformation, and then with a greater degree, reduces the influence of the "edge" effect when the rollers enter the workpiece and ensure high accuracy of geometric parameters in the initial section, and at next forming station with a higher degree of deformation also provides high dimensional accuracy by closely contacting the internal surface of the blank to the mandrel during the initial portion;

- the ratio of the degrees of deformation during the deformation of the sections of the periodic profile of greater and lesser wall thickness within 0.6 ÷ 0.8, which is optimal from the point of view of stability of the process of forming the periodic profile - to obtain alternating sections with a wave-like alternation of compressive radial stresses, creating a banding effect, increasing the stability of the workpiece along the entire length of the processing, it is also necessary to note that this ratio is determined experimentally, and when this change To a lesser and greater extent, the accuracy of geometric dimensions decreases and the likelihood of corrugation increases;

- forming of the workpiece with rollers, the profile of which is made at the entrance section with an angle of 3 ÷ 7 degrees, on the front working surface with an angle of 25 ÷ 35 degrees, with an angle of 7 ÷ 15 degrees and with a cylindrical belt at the apex equal to 0.3 ÷ 0.5 the thickness of the workpiece wall - to increase the stability of the deformation process and the dimensional accuracy, as the results of experimental studies revealed that: 1) the inlet section of the profile of the rollers with an angle of 3-7 degrees most effectively smoothes out the influx of metal in front of the roller, and at a smaller angle (<3 ° ) increase effort I deformation, at greater (> 7 °) - the effect of smoothing out the influx decreases; 2) the angle of the front working surface — the rake angle — 25–35 degrees creates the most favorable conditions for the metal flow along the forming mandrel in the deformation zone, since an increase in the front angle of more than 35 degrees leads to metal tightening and cracks, and a decrease in the angle of less than 25 degrees leads to an increase in deformation forces and the phenomenon of “rolling” - an increase in the diametrical dimensions of the workpiece; 3) the angle of the back surface - the rear angle - 7 ÷ 15 degrees is optimal and ensures high quality of the processed surface, so with a small back angle (<7 °) and a larger (> 15 °) surface finish deteriorates - peeling is observed at small angles, and at large angles - surface undulation; 4) a cylindrical belt at the top of the profile, equal to 0.3 ÷ 0.5 of the wall thickness of the workpiece, provides high wear resistance of the rollers and, therefore, the quality of the machined surface, such a belt size is optimal at high pressure on the roller, so with a small belt size, (< 0.3 wall thickness) or its absence, the roller wears out quickly on the sharp peaks of the profile, as a result, the surface cleanliness after drawing deteriorates, i.e. the surface of the machined part becomes rough, and when the size of the girdle is more than 0.5 of the wall thickness, the radial and axial forces increase, which increases the likelihood of the appearance of braces and cracks;

- conjugation of the lead-in section, the front and rear surfaces and the cylindrical belt profile of the rollers along a radius equal to 0.25 ÷ 0.55 of the wall thickness of the workpiece - to ensure smooth growth of deformations, since there are no radii or their small value (<0.25 wall thickness) leads to peeling of the treated surface, and large values of the radius (> 0.55 of the wall thickness) cause a deterioration in the quality of the treated surface as a result of rounding and a decrease in the length of the cylindrical girdle;

- execution on the end surfaces of the rollers of the persistent annular grooves with a depth of 0.3 ÷ 0.7 of the wall thickness of the workpiece and with a radius of profile equal to 2 ÷ 3 the wall thickness of the workpiece and a diameter of 0.6 ÷ 0.8 of the diameter of the roller - to compensate for bends and deflection of the rollers from the action of significant axial and radial forces of the hood and as a result to reduce runout and vibration of the rollers and, therefore, to ensure high quality of the processed surface; it should be noted that the above ratios of the depth of the grooves and wall thickness, as well as the diameter of the grooves and the diameter of the rollers are optimal and determined experimentally, since:

1) with a groove depth of less than 0.3 wall thickness and with a groove profile radius of less than 2 workpiece wall thicknesses, the contact area of the grooves with the balls of the bearing assembly decreases and the pressure on the balls and thrust grooves increases, which increases the likelihood of wear of the contact surface with its subsequent increase roughness and, consequently, vibration of the rollers, worsening the surface quality of the workpieces; and with a groove depth of more than 0.7 wall thickness and a groove profile radius of more than 3 workpiece wall thicknesses, the contact area of the thrust surface of the grooves increases, which leads to an increase in friction forces and, consequently, to an increase in the metal resistance to plastic deformation and, ultimately, to significant energy costs;

2) when the diameter of the stop grooves is less than 0.6 of the diameter of the roller, the deflection and vibration of the tops of the rollers increase, which leads to a waviness of the surface being machined, and when the diameter of the stop grooves is more than 0.8 of the diameter of the rollers, the height of the profile of the rollers decreases, which affects the rolling forces and surface cleanliness and increases the likelihood of corrugation.

Studying the level of technology during the patent search for all types of information available in the countries of the former USSR and foreign countries, it was found that the proposed technical solution does not explicitly follow from the prior art, therefore, we can conclude that the criterion of "inventive step" ".

The essence of the invention lies in the fact that in the method of manufacturing thin-walled shells with a periodic profile of large diameter, in which the workpiece is deformed on a rotating mandrel with several rollers, in contrast to the prototype according to the invention, a workpiece with a bottom is used, which is installed on the mandrel with a clearance of 0.06 ÷ 0 , 08 the wall thickness of the workpiece with emphasis on its bottom, and the process of forming a periodic profile is carried out in two or more transitions with a variable degree of deformation, at the first transition at the end part of the workpiece, at subsequent transitions - in the initial section and its main part, while rollers of the same profile, made with a tapered lead-in section, a front working surface and a rear surface mating with each other, and with a cylindrical belt at the top, are moved only in the radial direction to the mandrel and from it with different feed sizes, and the mandrel is moved with the workpiece in the axial direction opposite to the drawing direction.

The invention is illustrated by the drawing, in which Fig. 1 shows the workpiece and the mandrel in the initial position and the first transition of the shaping of the workpiece at its end section, in Fig. 2 - the position of the workpiece and the mandrel at the beginning and at the end of the second transition, in Fig. 3 - node 4, the profile of the roller.

The workpiece 1 (Fig. 1) is installed on the mandrel 2 with a gap Δ and with an emphasis on the bottom so that the end face of the workpiece is at a distance l ₀ mm to the top of the rollers 3, determined from the equality of the volume of the section of the end of the workpiece before and after the first transition of the rotary hood .

At the beginning of the rotary hood include the rotation of the mandrel with a speed of S min ^-1 and the radial movement of the rollers with a feed F _roll mm / min. The first transition begins from the moment the rollers 3 touch at point 0 (Fig. 1) at a length l ₀ mm and ends at the moment the rollers 3 exit the workpiece in a section 4 ÷ 5 at a length l ₁ mm. The forming of sections with a periodic profile is carried out with the axial movement of the mandrel 2 with the workpiece 1 with a constant value of the axial feed F _opr mm / min and a variable value of the radial feed of the rollers F _roll mm / min.

As a result, the profile trajectory of the first transition is a combination of sections: a conical section 0-1 - a roller entry section, a cylindrical section 1-2 with a thickness of t ₁ mm and a degree of deformation of e ₁ %, a conical section 2-3, a cylindrical section 3-4 s a thickness of t ₂ mm and a degree of deformation of e ₂ % and a conical section 4-5 is a section of the quick exit of the rollers from the workpiece.

The value of the radial feed of the rollers 3 in sections 0-1 and 2-3 is equal to F _roll mm / min, in sections 1-2 and 3-4 F _roll = 0 mm / min, in section 4-5 the radial feed of the rollers upon exiting the workpiece , 1.5-2.5 times the radial feed in the previous sections 0-1, 2-3.

The degree of deformation in the conical section of the entry of the rollers 0-1 varies from 0% at point 0 to e ₁ % at point 1 and in the first cylindrical section 1-2 remains equal to e ₁ %. In the second conical section 2-3, the degree of deformation increases from e ₁ % to e ₂ % and in the second cylindrical section is e ₁ = (0.6 ÷ 0.8) e ₂ , i.e. in the first cylindrical section with a larger wall thickness t ₁ mm, the degree of deformation is less than in the second cylindrical section having a smaller wall thickness t ₂ mm.

The second pass of the rotary hood (Fig. 2) begins when the rollers 3 touch the workpiece 1 in the initial section at point 6. The trajectory of the periodic profile of the second pass: cylindrical section 6-7 with a wall thickness of t ₁ mm with a degree of deformation of e ₁ %, conical section 7-8 with a degree of deformation increasing from e ₁ % to e ₂ %, a cylindrical section 8-9 with a thickness of t ₂ mm with a degree of deformation e ₂ % and so on, alternating in the same sequence - a cylindrical section 10-11 with e ₁ % and wall thickness t ₁ mm, conical section 11-12, cylindrical section 12-13 with a thickness of t ₂ mm with a degree of deformation of e ₂ %, the conical section 13-14 of the quick removal of the rollers 3 from the workpiece.

The length of the processed part of the workpiece after the second transition l ₂ mm The total length of the workpiece after the second transition L mm is equal to (l ₁ + l ₂ ) mm - the sum of the processing lengths on the transitions (figure 2).

At the second transition, as well as at the first, the radial feed of the rollers F _roll mm / min at the exit from the final section is 1.5-2.5 times greater than the radial feed F _roll mm / min in the previous sections 7-8, 9- 10, 11-12. As in the first transition, the degree of deformation e ₁ % of the sections with a thickness of t ₁ mm is less than the degree of deformation e ₂ % of the sections with a thickness of t ₂ mm. The ratio of the degrees of deformation e ₁ % / e ₂ % is also equal to 0.6 ÷ 0.8.

At the first and second transitions, the mandrel with the workpiece is moved in the axial direction opposite to the drawing direction, with a thickness of t ₁ mm and a degree of deformation of e ₁ %, with a speed of S min ^-1 and an axial feed of F mm / min.

After the rotation of the hood, the rollers are retracted to their original position with a radial accelerated feed F _roll mm / min, the rotation of the mandrel is stopped and the workpiece is removed from the mandrel.

The puller in figure 1 and figure 2 conventionally not shown.

Example.

A hollow steel axisymmetric billet with an inner diameter of 911 mm, a length of 885 mm, and a wall thickness of 7.2 mm with a bottom is mounted on the mandrel of a vertical rolling mill ХПТ - 4 (Р = 100 tf) with the bottom of the workpiece resting on the end of the mandrel.

The workpiece is installed with a gap between its inner surface and the mandrel equal to 0.5 mm.

соответствует формуле изобретения (

=0,06÷0,08).The ratio of the gap D and the diameter of the workpiece D ₀ is

corresponds to the claims (

= 0.06 ÷ 0.08).

Processing Modes:

The rotation speed of the mandrel S = 30 min ^-1 .

Axial feed F _def = 60 mm / min.

The wall thicknesses t ₁ and t ₂ and the degree of deformation e ₁ % and e ₂ % are given in table No. 1.

Radial feed of rollers F _roll mm / min during the formation of a periodic profile:

Table number 2 1 transition 2 transition Periodic sections F _roll mm / min Periodic sections F _roll mm / min 0-1 3.6 6-7 0 1-2 0 7-8 3.6 2-3 3.6 8-9 0 3-4 0 9-10 3.6 4-5 5,6 10-11 0 11-12 3.6 12-13 0 13-14 5,6

The value of the radial feed of the rollers when they exit the end sections of the workpiece 4-5 (first pass) and 13-14 (second pass) is 1.6 times larger than the feed rate in the previous sections, i.e. 5.6 / 3.6 = 1.6. Thus, the value of the radial feed at the exit of the rollers from the workpiece in the final sections (4-5 and 13-14), exceeding the feed of the rollers in the previous sections (0-1, 2-3, 7-8, 9-10 and 11-12 ) 1.6 times, which corresponds to the claims (1.5-2.5 times).

, что соответствует формуле изобретения [h=(0,3÷0,5)t₀]. Радиус сопряжения r=3 мм составляет 0,42 толщины стенки заготовки

, что соответствует формуле изобретения [r=(0,25÷0,55)t₀].The rotational hood at the first and second transition is carried out by rollers (Fig. 4) with a conical lead-in section (α _snap = 5 °), a conical front surface (ρ = 30 °), a conical rear surface (γ = 10 °), a cylindrical belt (h = 3 mm) at the apex, which are conjugate in radius (r = 3 mm). The length of the cylindrical belt h = 3 mm is 0.42 of the wall thickness of the workpiece

that corresponds to the claims [h = (0.3 ÷ 0.5) t ₀ ]. The mating radius r = 3 mm is 0.42 of the wall thickness of the workpiece

that corresponds to the claims [r = (0.25 ÷ 0.55) t ₀ ].

The rotational hood at the first and second transition is performed by rollers with a diameter of D _roll = 500 mm with annular stop grooves (Fig. 3) with a depth of b = 3.15 mm, a profile radius of R = 17.1 mm and a diameter of D _k = 360 mm.

The rollers 3 rotate at a speed (S _roll min ^-1 ) equal to the speed (S min ^-1 ), rotation of the workpiece with a mandrel (S _roll = S = 30 min ^-1 ) on the balls 4, which in turn abut against the supporting surface of the grooves rings 5.

The rotation of the rollers 3 is carried out from the deformation interaction with the workpiece 1.

The depth of the grooves, the radius of the profile of the grooves and the diameter of the stop grooves are:

depth b = 0.49t ₀ (3.5 / 7.2 = 0.49), b = (0.3 ÷ 0.7) t ₀ - according to the claims,

radius R = 2,37t ₀ (17,1 / 7,2 = 2,37), R = (2 ÷ 3) t ₀ - according to the claims,

diameter D _k = 0.49D _p (360/500 = 0.72), D _k = (0.6 ÷ 0.8) D _p - according to the claims.

Thus, the depth b mm, the radius of the profile R mm and the diameter D _to mm are made in accordance with the claims.

The implementation of the method of manufacturing thin-walled shells with a periodic profile of large diameter and length in accordance with the invention provides the manufacture of shells with high stability of the process of forming, providing high accuracy and surface quality.

The invention can be used in the production of various shells of steel, stainless steel and aluminum alloys of large diameter and length with a periodic profile in the form of a combination of alternating sections of conical, cylindrical shapes with different wall thicknesses.

The specified positive effect is confirmed by testing prototypes of parts made by this method.

Currently, technical documentation has been developed, tests have been carried out, serial production of the products by the proposed method is planned.

Claims (7)

1. A method of manufacturing thin-walled shells with a periodic profile of large diameter, including forming a periodic profile by deformation of the workpiece on a rotating mandrel with several rollers, characterized in that they use a workpiece with a bottom, which is installed on the mandrel with a gap of 0.06 ÷ 0.08 wall thickness blanks, with emphasis on its bottom, and the process of forming a periodic profile is carried out in two or more transitions, at the first of which the deformation is carried out with a variable degree of deformation at the end section of the workpiece, at subsequent transitions - at the initial section of the workpiece and on its main part, using the same profile rollers made with a tapered lead-in section, a front working surface and a rear surface mating with each other, and with a cylindrical girdle on top which move in the radial direction to and from the mandrel with a different feed rate, and the mandrel is moved with the workpiece in the axial direction opposite to the drawing direction. 2. The method according to claim 1, characterized in that the radial feed of the rollers when they exit the end sections of the workpiece is 1.5 ÷ 2.5 times higher than the radial feed in the previous sections. 3. The method according to claim 1, characterized in that at first with a lower degree of deformation a section of a profile with a larger wall thickness is formed, and then with a greater degree of deformation a section with a smaller wall thickness is formed, and then the sections are alternated in the same sequence. 4. The method according to claim 1, characterized in that the ratio of the degrees of deformation during deformation of the sections of the periodic profile with a larger and smaller wall thickness is set within 0.6 ÷ 0.8. 5. The method according to claim 1, characterized in that the rollers are used, made at the entrance section with an angle of 3 ÷ 7 °, on the front working surface with an angle of 25 ÷ 35 °, on the back surface with an angle of 7 ÷ 15 °, s a cylindrical girdle on top equal to 0.3 ÷ 0.5 the thickness of the wall of the workpiece. 6. The method according to claim 1, characterized in that the entry portion, the front and rear surfaces and the cylindrical belt of the rollers are mated in a radius equal to 0.25 ÷ 0.55 of the wall thickness of the workpiece. 7. The method according to claim 1, characterized in that the use of rollers, on the end surfaces of which are made persistent annular grooves with a depth of 0.3 ÷ 0.7 of the wall thickness of the workpiece, with a radius of profile equal to 2 ÷ 3 of the wall thickness of the workpiece, and diameter equal to 0.6 ÷ 0.8 of the diameter of the roller.

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