RU2449848C1 - Method of rotary drawing of thin-wall shells with bulges - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming. Proposed method comprises fitting tubular billet onto mandrel and acting thereon by deforming rollers in two or several passes. Tubular billet shaping is performed on main and adjacent sections, on sections with outer and inner buldges and on sections of deforming rollers engagement and disengagement. Said rollers are displaced on engagement sections along convex/concave circle arc paths and, on disengagement sections, along concave/convex circle arcs. Angle of tangent inclination to circle arcs in inflection zone is set equal to 5-30°. Shaping on sections of tubular billet joint is performed to radius making at least one thickness of tubular billet wall. Shaping of tubular billet inner buldges is carried out by rollers with working surface profile composed of conical and cylindrical sections. Length of cylindrical section and radius of toroidal sections make 0.2-0.4 and 0.4-0.8 of tubular biller thickness, respectively. Clearances between tubular billet inner surface and mandrel in shaping outer and inner buldges are set equal to (0.01÷0.1)t₀ and (0.15÷0.5)t₀, where t_0(mm) is tubular billet wall thickness.

EFFECT: high-quality surface, high precision of sizes and factor of metal utilisation.

7 cl, 6 dwg, 1 tbl, 3 ex

Description

The invention relates to the field of metal forming, namely the manufacture of thin-walled axisymmetric parts from low-carbon and alloy steels, as well as aluminum alloys by rotational drawing, for example, various shells - cylindrical, conical, with a complex profile of a combination of cylindrical, conical and curved sections, as well as thin-walled shells with a periodic profile in the form of alternating thickenings and shells with terminal thickenings.

The design feature of these parts is the different thickness of the end and main sections, which is due to the presence of internal and external threads at the ends of the parts for connection with plugs and caps, as well as with other parts.

The manufacture of such parts using a rotary hood allows you to get thickenings in various sections of the shells, instead of mechanical (turning) processing.

The most important problem in the production of shells of various types by methods of rotational drawing (rotational drawing, rotational crimping, etc.) is the stability of the process in the deformation zones, affecting the quality of the surface and the accuracy of the geometric shape.

The surface quality in the technical literature is understood as the height of microroughnesses, ruffles, waviness, traces of rollers, which in size do not lead the wall thickness beyond the limits of permissible deviations, as well as corrugations, folds and weights, which bring the wall thickness and the diameters of the shells beyond the limits of permissible deviations.

As shown by many years of experience in rotational drawing at machine-building enterprises, the urgent problem in increasing the stability of the process of rotational drawing of shells in order to ensure high surface quality and manufacturing accuracy is the problem of reducing tool vibrations and tooling of rolling mills, especially the elimination of resonance phenomena - the coincidence of frequencies of natural and forced vibrations of parts and knots of the mill and rolled shells.

In addition, the most important conditions for the steady progress of the rotational drawing process are the choice of processing modes in individual sections and transitions of the rotary hood, the choice of roller profiles, the paths of the rollers, the choice of gaps between the workpiece and the mandrel, etc.

Therefore, obtaining thin-walled shells of various profiles with high quality processing, accuracy and high metal utilization is an urgent task in the production of shell parts.

Known methods of rotational drawing: classical rotational drawing of cylindrical surfaces with decreasing outer diameter, wall thickness and increasing the length of the workpiece, rotating crimping with decreasing workpiece diameter, rotating drawing by projection, rotation drawing, etc. (see the book by N.N. Mogilny. Rotational drawing shell parts on machines. - M.:, Mechanical Engineering, 1983).

The disadvantages of the known methods in relation to the problem of obtaining thin-walled shells of various shapes is the low accuracy and surface quality due to the complexity of the shape and the small wall thickness of the shells.

There is a way to obtain parts with individual sections of the generatrix obtained by pairing a straight line with an arc of a given radius by rollers with a profile corresponding to the configuration of the profile section of the generatrix on a prefabricated mandrel (see the book by V.G. Kaporovich. Break-in of metal products in production. - M.: Engineering, 1973, p. 81, Fig. 35.

The disadvantage of this method is the inability to process the workpiece over the entire surface.

There is also a method of crimping pipe billets (see the book by M. A. Gredor. Pressing and rotational extrusion. - M.: Mechanical Engineering, 1971, p. 47, Fig. 28 "a", "b") with a roller on collapsible mandrels, where a large number of neck compression passes are required and there are no operations on the rotational drawing of cylindrical surfaces (Fig. 28 "b"), which is typical for shells with a short cylinder length and is unacceptable in the production of thin-walled shells of various thicknesses and shapes having a significant cylinder length.

The closest in technical essence and the achieved technical result is a method of rotational drawing of cylindrical shells with external end thickenings (see the book of M. A. Gredor. Pressure work and rotational extrusion. - M .: Mechanical Engineering, 1971, pp. 110-111 , fig. 66). At the beginning, a cylindrical billet obtained by an hood in the form of a cap with a bottom is installed and fixed on the mandrel of a three-roller machine (item 1). Then the pressure rollers are pressed into the workpiece, providing the formation of an external thickening at the bottom of the part (item 2).

At position 3, the rollers thin the wall to a predetermined thickness along the entire length of the main rectilinear section to thicken at the end of the workpiece (key 4).

In this way, external thickenings are obtained, and it is impossible to obtain internal thickenings, in addition, the disadvantages of this method include the use of a semi-finished hood, rather than tube blanks, which reduces the metal utilization rate.

This method is adopted by the authors for the prototype.

As can be seen from this technical solution, in the process of forming blanks, no technical solutions are used that increase the surface cleanliness and accuracy of geometric dimensions, namely, the optimal ratios of the degrees of deformation and processing conditions at transitions and at different processing sections, the gaps between the mandrel and the inner surface of the workpiece and rational profile of rollers.

The reasons that impede the achievement of the specified technical result when using the known method adopted by the authors for the prototype include the inability to obtain internal thickenings and the lack of technical solutions to improve the cleanliness of the processed surface and the accuracy of geometric dimensions.

In addition, the known method adopted for the prototype provides for the production of only cylindrical shells that do not have sections of the inflection of the generatrix, that is, shells with a rectilinear generatrix with external end thickenings.

Thus, the objective of this technical solution was to create a method of rotational drawing of cylindrical shells with external end thickenings from blanks in the form of a cap with a bottom, obtained by stamping from a circle.

Common signs with the method proposed by the applicants is the installation of the workpiece on the mandrel, fixing on the mandrel and the impact on it with deforming rollers for one or more transitions.

Unlike the prototype, in the method proposed by the applicant for the rotational drawing of thin-walled shells with thickenings, tube blanks are shaped on the main and mating sections, on sections with external and internal thickenings, and on the sections of the input and output of the deforming rollers, which are moved along the path along the path in the form convex-concave circular arcs, and in the exit sections in the form of concave-convex circular arcs, the angle of inclination of the tangent to the circular arcs in the inflection zone is set within 5 ÷ 3 0 °, shaping at the mating sections of the pipe billet is carried out along the radius of at least one wall thickness of the pipe billet, and shaping of the internal thickenings of the pipe billet is carried out with rollers with the profile of the working surface in the form of a combination of conical, toroidal and cylindrical sections, the length of the cylindrical section and the radius of the toroidal section respectively 0.2–0.6 and 0.4–0.8 of the wall thickness of the pipe billet, while the gaps between the inner surface of the pipe billet and the mandrel during shaping Hovhan external and internal nubs define respectively equal (0,01 ÷ 0,1) t ₀ and (0,15 ÷ 0,5) t ₀ where t ₀ (mm) - thickness of the tube wall of the workpiece.

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

- the shape of the tube billet in the areas of input and output of the rollers is performed with a feed rate and a rotation speed of 10 ÷ 20% of a given feed rate and rotation speed in the main section;

- the shaping of the pipe billet in all areas of the processed surface is performed with the ratio of the value of the rotation speed of the billet to the feed within (0.6 ÷ 0.95) mm ^-1 ;

- the shape of the tube billet at the last transition when thinning the wall is carried out with a degree of deformation of 0.6 ÷ 0.9 of the total degree of deformation;

- the shape change of the pipe billet at the last transition on all sections of the processed surface is performed with a feed rate and rotation speed of 0.6 ÷ 0.99 feed rate and rotation speed at previous transitions;

- the shape of the pipe billet in the mating sections is carried out with the value of the speed and feed of the workpiece, comprising 0.5 ÷ 0.75 speed and feed in the main section;

- the shaping of the internal thickenings is carried out with a degree of deformation during thinning of the wall, component 0.1 ÷ 0.4 of the total degree of deformation of the main section;

- the shape change of the internal thickenings is made up with a feed rate and a rotation speed of 0.5 ÷ 0.9 feed rates and rotation speeds at previous transitions.

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.

These signs, distinctive from the prototype and to which the requested amount of legal protection applies, are sufficient in all cases.

The objective of the invention is to provide the possibility of rotational drawing of thin-walled shells with external and internal end thickenings and bends forming in the form of mating cylindrical, conical and curved sections with high quality of the machined surface and accuracy of geometric dimensions due to the high stability of the forming process.

The specified technical result in the implementation of the invention is achieved by the fact that in the known method, including the installation of the workpiece, fixation on the mandrel and the impact on it with deforming rollers for one or more transitions, the feature is that the shape of the tube stock is carried out on the main and mating sections, on areas with external and internal thickenings and on the input and output sections of the deforming rollers that move along the path in the entrance areas in the form of convex-concave circular arcs , and in the exit sections in the form of concave-convex circular arcs, the angle of inclination of the tangent to the circular arcs in the inflection zone is set within 5–30 °, the shape change at the mating sections of the tube stock is carried out along the radius of at least one wall thickness of the tube stock, and the forming of the internal thickenings of the pipe billet is carried out by rollers with the profile of the working surface in the form of a combination of conical, toroidal and cylindrical sections, the length of the cylindrical section and the radius of the toroidal section, s Responsibly, 0.2 ÷ 0.6 and 0.4 ÷ 0.8 are equal to the wall thickness of the tube billet, while the gaps between the inner surface of the tube billet and the mandrel during the shaping of the external and internal thickenings are set, respectively, (0.01 ÷ 0 , 1) t ₀ and (0.15 ÷ 0.5) t ₀ , where t ₀ (mm) is the wall thickness of the pipe billet.

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

- the shape of the tube billet in the main and mating sections, in areas with external and internal thickenings and in the sections of the inlet and outlet of the deforming rollers, which are moved in the inlet sections along the path in the form of convex-concave circular arcs, and in the exit sections in the form of concave-convex circular arcs to ensure a smooth increase and decrease in deformation at the entrance and exit and eliminate the "edge effect", that is, the phenomenon of corrugation and bulging of metal in the areas of entry and exit of the rollers, and to prevent sticking lla on the rollers, as at the time of entry into and exit from the blank workpiece is moved on rollers convex trajectory with an angle of inclination of the tangent to the trajectory of zero;

- the angle of inclination of the tangent to the arcs of circles in the bend within 5 ÷ 30 ° to ensure high stability of the forming process, the accuracy and quality of the processed surface, the value of the angle of inclination of the tangent to arcs in the bend - the zone of connection of the arcs within 5 ÷ 30 ° is optimal, as at an angle of less than 5 ° the length of the inlet and outlet sections increases and the metal utilization coefficient decreases, and with an angle of more than 30 ° the smoothness of the strain increases, which increases the likelihood of corrugation and metal sticking to input and output rollers;

- changes in the mating sections of the pipe billet along the radius of less than one wall thickness of the pipe billet to increase the stability of the forming process, surface quality and accuracy of geometric dimensions in these areas, since corrugations and bulging of metal occur in the mating sections of various surfaces due to uneven deformation, then the formation of these sections along the radius provides a smooth increase in deformation along the metal flow lines, that is, along the forming mandrel, and this eliminates the appearance of ofr and buckling, and with smaller radii of the mating - less than one wall thickness of the workpiece due to a sharp change in the characteristics of the flow of metal in these areas, according to the results of experimental work, buckling of metal occurs;

- shaping the internal thickenings of the tube billet with rollers with a profile of the working surface in the form of a combination of conical, toroidal and cylindrical sections - to ensure high stability of the forming process, and thereby improve the quality of the machined surface and dimensional accuracy, since the presence of a cylindrical section at the top of the profile and toroidal sections mating with the cylindrical and conical sections of the front and rear surfaces of the roller, allows you to smooth the work surface and create a radial flow of metal to the mandrel, which determines the accuracy of the geometric shape of the internal thickening and the quality of the surface to be treated;

- the implementation of the profile of the working surface of the rollers with a cylindrical length and a radius of the toroidal section, respectively, equal to 0.2 ÷ 0.6 and 0.4 ÷ 0.8 of the wall thickness of the pipe billet - to increase the frequency and accuracy of the machined surface, since the toroidal and cylindrical surface the vertices of the profile smooth out irregularities of the processed surface, the values, respectively, of 0.2 ÷ 0.6 and 0.4 ÷ 0.8 of the wall thickness of the workpiece are optimal, since at lower and higher values the surface cleanliness worsens, and at less than 0.3 and 0 , 4 wall thickness fuss cabins are screw recesses, with more than 0.6 and 0.8 wall thicknesses, internal thickenings are not formed due to an increase in the contact area in the deformation zone and the absence of metal flow to the mandrel;

- the selection of the gaps between the inner surface of the pipe billet and the mandrel during the shaping of the external and internal thickenings within, respectively, equal to (0.01 ÷ 0.1) t ₀ and (0.15 ÷ 0.5) t ₀ , where t ₀ ( mm) is the wall thickness of the tube billet, to ensure the stability of the deformation process, since when forming external thickenings with a gap of less than 0.01t ₀ (mm), friction forces increase, which leads to the formation of transverse corrugations, and with a gap of more than 0.01t ₀ (mm ) surface frequency worsens and dimensional accuracy decreases due to the appearance of longitudinal corrugations, when forming internal thickenings equal to (0.15 ÷ 0.5) t ₀ , to ensure the stability of the process of forming internal thickening, since in this case there is a rotation hood and rotational crimping of the workpiece with thinning the wall, therefore, when reducing the gap less than 0.15t ₀ (mm) increases the number of transitions and the complexity of manufacturing shells, and with a gap of more than 0.5t ₀ (mm), the metal flow in the radial direction decreases, as a result, there is no contact of the inner surface of the workpiece with the mandrel, which leads to corrugation, that is, the process of forming internal thickenings with a gap of more than 0.5 t _{0 is} unstable;

Signs characterizing the invention in specific forms of execution, allow, in particular, due to:

- shaping of the tube billet at the inlet and outlet sections of the rollers with a feed rate and rotation speed of 10 ÷ 20% of the feed rate and rotation speed in the main section, to increase the stability of the forming process in these sections, which is expressed as a result of a decrease in the strain rate, in warning at these modes of adherence of metal particles to the working surface of the rollers, which increases the surface cleanliness of the workpiece; processing modes - the feed rate and rotation speed, respectively, 10 ÷ 20% of the feed rate and rotation speed in the main section, are optimal for the inlet and outlet sections of the rollers, determined empirically: at values of more than 20% the surface finish deteriorates due to increase in metal sticking to rollers, at values less than 10%, the productivity of the forming process is reduced;

- the shape of the tube billet in all areas of the workpiece with the ratio of the speed of rotation of the billet to the feed within 0.6 ÷ 0.95 to increase the stability of the process of forming, the essence of which is expressed in the fact that with these ratios of modes the vibrations of the AIDS system are reduced and resonance phenomena are eliminated and, in the final result, the surface finish is improved, and, according to the applicants, according to the results of research and experimental work, this ratio is optimal cial from the viewpoint of reducing the amplitude and frequency of oscillation tool - deforming rollers; since when changing this ratio in one direction or another, the surface finish of the workpiece deteriorates, which is reflected in an increase in the height of microroughnesses, the accuracy of the geometric dimensions also decreases due to the appearance of waviness and small corrugations, and with resonance, large corrugations;

- shaping of the tube billet at the last transition when thinning the wall with a degree of deformation of 0.6 ÷ 0.9 of the total degree of deformation, to increase the stability of the forming process, since the last transition is the most critical and forms the final dimensions of the shell in diameter and wall thickness, then redistributing the deformation in this way to 0.6 ÷ 0.9 of the total deformation, i.e., upward in comparison with the previous (or previous transitions), increase the accuracy of the geometric dimensions, that is, this value of the degree of deformation at the last transition is optimal: with a decrease of less than 0.6 of the total degree of deformation, the accuracy of the geometric dimensions decreases due to the fact that the phenomenon of “rolling” occurs, which is an increase in diameter due to a decrease in rolling forces, and at more than 0, 9, the total degree of deformation increases the rolling force, which reduces the accuracy of the geometric dimensions and increases the likelihood of corrugation and cracks;

- shaping the tube stock at the last transition with a feed rate and workpiece rotation speed of 0.6 ÷ 0.99 feed rates and rotational speeds at previous transitions to increase the stability of the forming process, the accuracy of the geometric dimensions and the quality of the surface being treated, since the degree of deformation at the last the transition is higher than at the previous transitions, then setting the feed and rotation speed of the workpiece 0.6 ÷ 0.99 the feed rate and rotation speed at the previous transitions, get accurate dimensions and high achestvo surface; feed rates and workpiece rotation speeds of 0.6 ÷ 0.99 feed rates and rotational speeds of previous transitions are optimal, since for feeds and speeds less than 0.6 feed and speed values at previous transitions, surface quality deteriorates and the accuracy of the processed workpieces from -for the phenomenon of “rolling”, and at feed rates and speeds of more than 0.99 feed and speed values at previous transitions, rolling forces increase, which leads to the appearance of corrugations and cracks;

- shaping of the tube billet at the interface with the speed and feed, which, respectively, 0.5 ÷ 0.75 speed and feed at the main site, to increase the stability of the forming process, the accuracy of the geometric dimensions and the quality of the machined surface, as at the interface due to the non-uniformity of deformation at the bends of the generatrix in these areas, metal bulging occurs, then reducing the speed and feed to the indicated values, this reduces the strain rate while maintaining uu efforts deformation and, as a result, eliminate the appearance of bulges and corrugations in these areas, the values of 0.5 ÷ 0.75 are optimal: the decreases and increases of the values of these limits arise, respectively, and rolling phenomena and buckling;

- thinning of the wall during the formation of internal thickenings of the tube billet with a degree of deformation of 0.1 ÷ 0.4 of the total degree of deformation of the main section, to ensure the stability of the deformation process, since the process of forming internal thickenings consists in the simultaneous action of rotational drawing and rotational crimping with thinning of the wall , then thinning of the wall with a degree of deformation of less than 0.1 of the total degree of deformation will require an increase in the number of transitions, and when thinning with a degree of deformation, more ie 0.4 of the total degree of deformation occurs at the buckling deformation of the metal portion of the uneven flow of metal in the zone of the end stop of the mandrel;

- selection of the feed rate and rotation speed during the shaping of the internal thickenings of the tube stock, component 0.5 ÷ 0.9 of the feed rate and rotation speed at previous transitions, to ensure high quality of the machined surface and the accuracy of the geometric shape, since the process of obtaining internal thickenings is due to the flow of metal both in the radial and axial directions as a result of simultaneous rotational drawing and rotational crimping in the forming section of the internal thickening, therefore, according to the results torture, reducing the processing regimes - the feed rate and rotation speed within 0.5 ÷ 0.9 feed rate and rotation speed of the previous transitions - increase the stability of the forming process, with feed values and speeds less than 0.5 and more than 0.9 feed rate and the speeds of the previous transitions occur, respectively, the phenomenon of rolling with an increase in the outer diameter and the incomplete filling of the thickening volume in the gap between the inner surface of the workpiece and the mandrel.

Signs that distinguish the proposed technical solution from the prototype are not identified in other technical solutions and are not known from the prior art in the process of conducting patent research, which allows us to conclude that the invention meets the criterion of "novelty."

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 rotational drawing of thin-walled shells with thickenings, which includes installing the tube stock on the mandrel, fixing it on the mandrel and exposing it to deforming rollers in one or more transitions, in contrast to the prototype, according to the invention, the tube stock is shaped on main and mating sections, in areas with external and internal thickenings and in the areas of entry and exit of the deforming rollers that move along the paths of the entrance in the form of convex-concave circular arcs, and in the exit sections in the form of concave-convex circular arcs, the angle of inclination of the tangent to the circular arcs in the inflection zone is set within 5 ÷ 30 °, the shape change at the mating sections of the pipe billet is carried out with a radius of at least one wall thickness of the tubular billet, and the forming of the internal thickenings of the tubular billet is carried out by rollers with a profile of the working surface in the form of a combination of conical, toroidal and cylindrical sections, the length of the cylindrical section a and the radius of the toroidal section are respectively 0.2 ÷ 0.6 and 0.4 ÷ 0.8 of the wall thickness of the pipe billet, while the gaps between the inner surface of the pipe billet and the mandrel during the shaping of the external and internal thickenings are set, respectively, (0 , 01 ÷ 0,1) t ₀ and (0,15 ÷ 0,5) t ₀ , where t ₀ (mm) is the wall thickness of the pipe billet.

The invention is illustrated by drawings, which depict: in Fig.1 - the process of rotational drawing of the shells with the formation of external thickenings at the ends of the workpieces, the original workpiece and the workpiece after the first and last transition of the rotational hood; figure 2 - the process of rotational drawing and rotational crimping with the formation of internal thickening at the end of the workpiece; figure 3 - profile of the rollers for the formation of internal thickenings; figure 4 - the process of rotational drawing and crimping of shells with a complex profile with the formation of external and internal thickenings at the ends of the workpieces and with sections of the mates in the main processing section; figure 5 - the trajectory of the rollers at the entrance and exit to the workpiece and from the workpiece; Fig.6 is a process of rotational drawing of shells with a periodic profile with the formation of external alternating thickenings and thinning.

Figure 1 shows the workpiece 1 in the initial position, the workpiece 2 after the first transition of the rotary hood, the workpiece 3 after the last transition, the rollers 4, the mandrel 5, and also:

Δ ₁ (mm) - the gap between the inner surface of the workpiece and the mandrel during the formation of external thickenings,

t ₀ (mm) - wall thickness of the original billet,

t ₁ (mm) is the wall thickness of the workpiece after the first transition of the rotary hood,

t ₂ (mm) is the wall thickness of the workpiece after the last transition of the rotational hood,

t _k (mm) is the thickness of the outer thickenings,

L _k (mm) - the length of the outer thickenings,

L _in. (mm) - the length of the plot of the entrance of the rollers into the workpiece,

L _out. (mm) - the length of the exit section of the rollers from the workpiece,

L _o. (mm) - the length of the main section,

F _oc . (mm / min) - axial feed of the rollers,

F _R (mm / min) - radial feed rollers,

S (min ^-1 ) is the rotation speed of the mandrel with the workpiece.

Figure 2 shows the workpiece 1 obtained by a rotational hood mounted on the mandrel 3, and the workpiece 2 after the formation of the internal thickening;

4 (I) - the position of the rollers at the beginning of the process of shaping the internal thickening;

4 (II) - the position of the rollers at the end of the process of forming the internal thickening;

t ₂ (mm) is the wall thickness of the main section of the workpieces,

t _k (mm) - wall thickness of the outer thickenings,

(мм) - толщина стенки внутреннего утолщения,

(mm) - wall thickness of the inner thickening,

(мм) - длина внутреннего утолщения,

(mm) - the length of the internal thickening,

Δ ₂ (mm) - the gap between the inner surface of the workpiece and the mandrel.

Figure 3 shows the profile of the rollers for the formation of internal thickenings with conical sections AB and EF of the front and rear surfaces associated with toroidal sections BC and DE of radius R (mm), and with a cylindrical section CD of length L (mm) of the profile tip, front angle β ^° and trailing angle γ ^° - the angles of inclination of the front and rear conical surfaces.

Figure 4 shows: billet 1 with a thickness of t ₀ (mm) mounted on mandrel 5, billet 2 after rotational drawing and rotational crimping with external thickenings at the ends of the billet;

Δ ₁ (mm) - the gap between the inner surface of the workpiece and the mandrel during the formation of the outer thickening on the cylindrical section AB,

t ₁ (mm) is the wall thickness of the workpiece after the first transition of the rotary hood,

t _k (mm) is the wall thickness of the outer thickenings in the area AB and FG,

L _k (mm) - the length of the outer thickenings in the sections AB and FG,

L ₀ (mm) - the length of the main processing section BF,

L _c. (mm) is the length of the mating sections of the processing CD and EF with radii R _c (mm);

workpiece 3 after the last transition of the rotational hood and rotary crimping with the formation of an internal thickening at the end of the workpiece,

Δ ₂ (mm) - the gap between the inner surface of the workpiece and the mandrel during the shaping of the internal thickening in the area GH,

t ₂ (mm) - wall thickness after the last transition of the rotational hood,

(мм) - толщина стенки внутреннего утолщения на участке GH,

(mm) is the wall thickness of the internal thickening on the plot GH,

(мм) - длина внутреннего утолщения на участке GH.

(mm) - the length of the internal thickening on the plot GH.

Figure 5 shows the process of rotational drawing in the areas of input and output of the rollers into the workpiece and from the workpiece with a curved convex-concave and concave-convex path of the rollers 4, where F _o (mm / min) is the axial feed of the rollers, F _R (mm / min) is the radial feed of the rollers, S (min ^-1 ) is the workpiece rotation speed, L _in (mm) is the length of the inlet section, L _out (mm) is the length of the exit section, α ^° is the angle of inclination of the tangent to the convex-concave and concave-convex sections of the curves in the inflection zone, (.) 0 - the inflection point of the convex-concave and concave-convex sections, R (mm) - The radius of curvature of portions, t ₀ (mm) wall thickness of the preform, t ₁ (mm) - thickness of the wall of the main portion of the blank after transitions rotary drawing, Δt (mm) - depth of rotary drawing, Δt = t ₀ -t ₁ (mm) H (mm) - the height of the inflection point.

(мм) - толщина стенки периодических утолщений заготовки после последнего перехода ротационной вытяжки, L_k (мм) - длина наружных концевых утолщений,

(мм) - длина периодических утолщений основного участка обработки, L_вх. (мм) и L_вых. (мм) - длина участков входа и выхода роликов на переходах ротационной вытяжки,

(мм) - длина периодических утонений основного участка обработки, F_oc. (мм/мин) - осевая подача роликов, F_R. (мм/мин) - радиальная подача роликов, S (мин^-1) - скорость вращения заготовки.Figure 6 shows the workpiece 1 in the initial position, the workpiece 2 after the first transition of the rotary hood, the workpiece 3 after the last transition, the rollers 4, the mandrel 5, Δ ₁ (mm) - the gap between the inner surface of the workpiece 1 and the mandrel 5; t ₀ (mm) is the wall thickness of the initial preform, t ₁ (mm) is the wall thickness of the preform after the first transition of the rotary hood, t ₂ (mm) is the wall thickness of the periodic thinning of the preform after the last transition of the rotational hood, t _k (mm) is the thickness walls of external end thickenings,

(mm) is the wall thickness of the periodic thickenings of the workpiece after the last transition of the rotational hood, L _k (mm) is the length of the outer end thickenings,

(mm) - the length of the periodic thickenings of the main processing area, L _in. (mm) and L _out. (mm) - the length of the sections of the input and output of the rollers at the transitions of the rotational hood,

(mm) - the length of the periodic thinning of the main processing area, F _oc . (mm / min) - axial feed of the rollers, F _R. (mm / min) - radial feed of the rollers, S (min ^-1 ) - workpiece rotation speed.

(мм).The length of the main processing section is the sum of the lengths of periodically repeated thickenings and thinning:

(mm).

The above method of rotational drawing of thin-walled shells is as follows.

The initial billet 1 (Figs. 1, 4, 6), made of a pipe by cutting it into measured billets and machined, is mounted on a mandrel 5 fixed in the spindle of a pressure-rolling machine.

Then the workpiece is fixed on the mandrel, pressing the ledge of the workpiece to the end surface of the mandrel. (The clip is conventionally not shown in the drawing).

The rotation of the spindle S (min ^-1 ) with the mandrel 1 and the workpiece 5 is set, the radial movement of the rollers 4 is F _R (mm / min) and the axial movement is F _oc (mm / min) with the introduction of the rollers 4 at the inlet section L _in (mm ) along a curved path in the form of convex-concave sections of curves with a radius of curvature R (mm) and an angle of inclination of the tangent α ^° in the inflection zone at point 0 (Fig. 5).

For several transitions form the main section of length L ₀ (mm) with a degree of deformation E (%) with a rotation speed S (min ^-1 ) and axial feed F _oc (mm / min).

At the first transition, the surface of the main section is formed with a wall thickness t ₁ (mm), with a degree of deformation E ₁ (%), and an axial feed F _oc (mm / min), as well as external thickenings with a gap Δ ₁ (mm), thickness t _k (mm) and a length L _k (mm).

(мм) и утонениями t₂ (мм) (фиг.6).At the last transition, the main section is formed with a degree of deformation E ₂ (%), with a rotation speed S (min ^-1 ), with an axial feed F _oc (mm / min) with external end thickenings t _k (mm) (Figs. 1, 4 ), with external alternating thickenings

(mm) and thinning t ₂ (mm) (Fig.6).

The exit of the rollers from the workpiece at all transitions of the rotary hood in sections L _o (mm) is also carried out along a curved path in the form of concave-convex sections of curves with a radius R (mm) and an angle of inclination of the tangent α ^° in the bend zone (Fig. 5).

Forming of the workpiece at the inlet and outlet sections of the rollers is performed with a feed rate and rotation speed of 10 ÷ 20% of the feed rate and rotation speed at the main processing section.

(мм) и длиной

(мм) с зазором Δ₂ (мм) между внутренней поверхностью заготовки и оправкой ротационной вытяжкой и ротационным обжимом концевого участка заготовки с утонением стенки с t_k (мм) до

(мм) со степенью деформации Е₃ (%), с подачей F_ос3 (мм/мин) и скоростью вращения заготовки S₃ (мин^-1).Then form the inner end thickening (figure 2, 4) with a thickness

(mm) and length

(mm) with a gap Δ ₂ (mm) between the inner surface of the workpiece and the mandrel with a rotary hood and a rotary crimp of the end section of the workpiece with thinning of the wall from t _k (mm) to

(mm) with the degree of deformation E ₃ (%), with the supply of F _OS3 (mm / min) and the speed of rotation of the workpiece S ₃ (min ^-1 ).

The physical meaning of the site forming with obtaining an internal thickening according to the applicants is as follows.

(мм) с одновременным утонением стенки с t_k (мм) до

(мм).At the same time, a rotational hood and a rotary crimp of the external end thickening obtained at previous transitions with the flow of metal in the radial and axial directions are carried out, while the metal fills the volume formed by the gap Δ ₂ (mm) along the length

(mm) with simultaneous thinning of the wall from t _k (mm) to

(mm).

The processing is carried out by rollers with a profile of the working surface in the form of a combination of conical (AB and EF) toroidal (BC and DE) with a radius R (mm) and a cylindrical (CD) length L (mm) sections (Fig.3).

When rotational drawing of thin-walled shells of a complex profile with a curved surface of the main section BF of length L ₀ (mm) (Fig. 4) in the mating sections CD and EF of length L _c (mm), shaping is performed along the radius R (mm) with a rotation speed S (min ^-1 ) and the feed rate F _oc (mm / min), comprising 0.5 ÷ 0.75 speed S and feed F _oc in the main section.

After the completion of the shaping, the rollers are retracted to their original position, the rotation of the mandrel with the workpiece is stopped, the workpiece is released from fixation and removed from the mandrel.

Example 1

A billet of 133 mm with a wall thickness of 13 mm after cutting pipes into workpieces and machining is installed on the mandrel, fix it on the mandrel and act on it with deforming rollers, in two transitions form the main and sections with external thickenings.

At the first transition on a press-rolling machine (Fig. 1), the workpiece is rotationally drawn with a degree of deformation E ₁ = 44.3% with a rotation speed S = 200 min ^-1 , axial feed F _OS = 240 mm / min, with the initial thickness the blanks t ₀ = 7 mm receive a wall t ₁ = 3.9 mm and two external end thickenings with a thickness t _k = 7 mm and t _k = 4.5 mm, a length L _k = 120 mm and L _k = 55 mm.

Then perform the second transition of the rotary hood with a rotation speed of S = 185 min ^-1 and the feed F _OS = 230 mm / min, with a degree of deformation E ₂ = 56.4%.

At the second transition, a wall t ₂ = 1.7 mm and two external end thickenings with a thickness t _k = 7 mm and t _k = 4.5 mm, a length L _k = 75 mm and L _k = 85 mm are obtained.

The total degree of deformation during the rotation hood of the main section

, длиной

со степенью деформации

.Then perform a rotational hood and rotational crimping (figure 2) to obtain an internal end thickening of thickness

long

with degree of deformation

.

The shaping of the inner thickening is performed by deforming rollers (Fig. 3) with a profile in the form of a combination of conical front and rear surfaces with inclination angles β = 15 °, γ = 15 °, toroidal surfaces with a radius R = 5 mm, a cylindrical surface with a length of L = 2 mm .

At the entrance and exit sections, the rollers are moved along a curved path (Fig. 5) in the form of convex-concave and concave-convex circular arcs with a radius of R = 144 mm, L _in = L _out = 40 mm, L _k = 19.9 mm, with an angle of inclination α ° = 8 ° tangent to arcs in the zone (point 0) of inflection, Δt = 4.5-1.7 = 2.8 mm, N = 2.8 / 2 = 1.4 mm, angle α ° is in the range of 5 ÷ 30 °, which corresponds to the claims.

Based on the experimental data for various angles of inclination of the tangent to the arcs in the bend zone of the trajectory, a table is compiled.

Table E% α ° Δt (mm) N (mm) R (mm) L _to (mm) L _in / L _out (mm) 60 3 ° 1021.6 53,4 106.9 5 ° 2,8 1.4 371.25 32.3 64.72 15 ° 41.1 10,4 21.3 30 ° 10.45 4.84 10.44 45 ° 4.78 2,8 6.76

An analysis of the results given in the table shows that, with an angle α less than 5 ° and more than 30 °, the lengths of the inlet and outlet sections L _in , L _out (mm) and the radius of the arcs R (mm), respectively, sharply (~ 2 times) increase and decrease, that at α> 30 ° the smoothness of the entrance and exit of the rollers into the workpiece is violated, and at α <5 ° the length of the entrance and exit of the rollers increases, and this reduces the utilization of metal (increases the consumption of metal).

Thus, the optimal value of the angle of inclination of the tangent to the arcs in the inflection zone (point 0) of the trajectory in the areas of input and output of the rollers, providing high surface quality and accuracy of geometric dimensions, is within (5 ÷ 30) °, which is reflected in the claims .

A rotational hood in the areas of input and output of the rollers is performed with the feed rate and rotation speed

и

и соответствует формуле изобретения /10÷20% величины подачи и скорости вращения на основном участке/.- at the first transition F _OS = 36 mm / min, S = 30 min ^-1 , which is 15% of the feed rate and 15% of the rotation speed in the main section:

and

and corresponds to the claims / 10 ÷ 20% of the feed rate and rotation speed in the main area /.

и

и соответствует формуле изобретения /10÷20% подачи и скорости на основном участке/.- at the second transition F _oc = 34.5 mm / min, S = 27.7 min ^-1 , which is

and

and corresponds to the claims / 10 ÷ 20% feed and speed in the main area /.

Rotary hood in all areas of the processed surface is performed:

- in the areas of entry and exit at the first transition F _oc = 36 mm / min, S = 30 min ^-1 with the ratio of the speed to feed S / F _oc = 0,83 mm ^-1 ;

- in the areas of entry and exit on the second pass F _oc = 34.5 mm / min, S = 27.7 min ^-1 , S / F _oc = 27.7 / 34.5 = 0.8 mm ^-1 ;

- in the main section (F _OS = 240 mm / min, S = 200 min ^-1 ) of the first transition S / F _oc = 200/240 = 0.83 mm ^-1 ;

- in the main section of the second transition (F _OS = 230 mm / min, S = 185 min ^-1 ), S / F _oc = 185/230 = 0.8; which corresponds to the claims: S / F = (0.6 ÷ 0.95) mm ^-1 , in all areas of the treated surface.

The degree of deformation in the second pass E ₂ = 56.4%, which with a total strain E _Σ = 75.7% is E ₂ = 56.4 / 75.7 = 0.75E _Σ , which also corresponds to the claims (E ₂ = (0.6 ÷ 0.9) E _Σ ).

The rotation hood at the second transition is performed with the feed rate and the rotation speed of the workpiece:

- in the areas of input and output of the rollers F _OS2 = 34.5 mm / min, S ₂ = 27.7 min ^-1 , which, respectively, constitute the feed rate and speed of the first transition:

F _oc2 / F _oc1 = 34.5 / 36 = 0.96, S ₂ / S ₁ = 27.7 / 30 = 0.92, F _oc2 = 0.96 _{F oc1} S2 = 0.92S1;

- in the main section F _OS2 = 230 mm / min, S ₂ = 185 min ^-1 , respectively, comprising the feed rate and the speed of the first transition:

F _oc2 / F _oc1 = _230/240 = 0.96, F _oc2 = 0.96 F _oc1

S ₂ / S ₁ = 185/200 = 0.92, S2 = 0.92S1,

which corresponds to the claims F ₂ = (0.6 ÷ 0.99) F ₁ , S ₂ = (0.6 ÷ 0.99) S ₁ .

The shaping of the internal thickening (Fig. 2) is carried out simultaneously by a rotary hood and rotational crimping by rollers with the length of the cylindrical surface of the profile tip (Fig. 3) L = 2 mm, which is 2/7 = 0.29, i.e. L = 0.29t ₀ , where t ₀ = 7 mm is the wall thickness of the workpiece, and corresponds to the claims L = (0.2 ÷ 0.6) t ₀ , and with a radius of the toroidal surface R = 5 mm, which is 5 / 7 = 0.71, that is, R = 0.71t ₀ and corresponds to the claims R = (0.4 ÷ 0.8) t ₀ .

The formation of external and internal thickenings is carried out by methods of rotational drawing and rotational crimping with gaps between the inner surface of the workpiece and the mandrel, respectively, equal to Δ ₁ = 0.5 mm and Δ ₂ = 1.8 mm, which with a workpiece wall thickness of 7 mm is 0.071 t ₀ and 0.26t ₀ (0.5 / 7 = 0.071 and 1.8 / 7 = 0.26), which corresponds to the claims (Δ ₁ = (0.01 ÷ 0.1) t ₀ and (Δ ₂ = (0.15 ÷ 0.5) t ₀ ).

, что при суммарной деформации ротационной вытяжки на основном участке E_Σ=75,7% составит

, что соответствует формуле изобретения

.The shaping of the internal thickening (figure 2) is carried out with thinning of the wall with t _to = 7 mm and t _to = 5.75 mm with a degree of deformation

that with the total deformation of the rotation hood in the main section E _Σ = 75.7% will be

that corresponds to the claims

.

The shaping of the internal thickening (figure 2) is carried out with the value of the axial feed F _oc3 = 125 (mm / min) and rotation speed S ₃ = 112 (min ^-1 ), which is F _oc3 / F _oc2 = _125/230 = 0.54 , S ₃ / S ₂ = _112/184 = 0.61 and corresponds to the claims: F _oc3 = (0.5 ÷ 0.9) F ₂ , S ₃ = (0.5 ÷ 0.9) S ₂ .

After processing, the rotation of the spindle with the mandrel is stopped, the rollers are retracted to their original position, the workpiece is released from fixation and removed from the mandrel.

Example 2

The billet of hot-rolled steel pipes ⌀127x7 mm after cutting the pipes into billets and machining is mounted on a mandrel, fixed and subjected to rotational drawing and rotational crimping with rollers for 2 transitions (Fig. 4).

At the first and second transitions, a rotational hood is drawn in the cylindrical section of the aircraft, a rotational hood in the profile section of DE and the mating sections of CD and EF along the radii R _s = 50 mm and R _s = 25 mm and a rotational hood with a rotational crimp in the section FG and GH s the formation of an external thickening in the area AB and internal - in the area GH.

When the wall thickness of the workpiece t ₀ = 5 mm, the radii of the mating sections R _c = 50 mm and R _c = 25 mm exceed the wall thickness of the workpiece, which corresponds to the claims (R _c > t ₀ ).

Workpiece rotation speed and feed:

at 1 transition - in the main section S ₁ = 100 min ^-1 , F _oc1 = 110 mm / min,

- in the mating areas S _c = 60 min ^-1 , F _c = 66 mm / min,

at the 2 transition - in the main section S ₂ = 90 min ^-1 , F _oc2 = 100 mm / min,

- in the mating areas S _c = 54 min ^-1 , F _c = 60 mm / min,

that is, S _c / S ₁ = _60/100 = 0.6, F _c / F _oc1 = _66/110 = 0.6 - at the first transition

S _c / S ₂ = 54/90 = 0.6, F _c / F _os2 = _60/100 = 0.6 - on the second transition,

which corresponds to the claims: S _c = (0.5 ÷ 0.75) S and F _c = (0.5 ÷ 0.75) F _OS .

Ratios of speeds and feeds at transitions:

S ₂ / S ₁ = _90/100 = 0.9, F _oc2 / F _oc1 = _100/110 = 0.91, which corresponds to the claims: S ₂ = (0.6 ÷ 0.99) S ₁ and F _oc2 = (0.6 ÷ 0.99) F _oc1 .

Total degree of deformation

Deformation degree at 1 transition

,Deformation degree at 2 transition

,

which is E ₂ / E _Σ = 44/72 = 0.61 and corresponds to the claims E ₂ = (0.6 ÷ 0.9) E _Σ .

The ratio of the magnitude of the rotation speed to the feed quantity at the first transition S ₁ / F _oc1 = _100/110 = 0.91 (mm ^-1 ), at the second transition S ₂ / F _oc2 = _90/100 = 0.9 (mm ^-1 ) that corresponds to the claims: S / F = (0.6 ÷ 0.95) mm ^-1 .

Relations between the degrees of deformation and processing conditions during the shaping of the main processing section and the internal thickening, the ratio of the rotation drawing modes at the inlet and outlet sections of the rollers and the main section, the ratio of the gaps between the inner surface of the workpiece and the mandrel during the shaping of the external and internal thickenings, the trajectory of the rollers when input and output and the ratio of the sizes of the profile of the rollers, see Example 1.

Example 3

The billet from steel hot-rolled pipes ⌀325x18 after cutting into billets, calibrations according to the outer diameter and machining is installed on the mandrel, clamped and subjected to a rotational hood for two transitions (Fig.6).

At the first transition, a rotational hood is performed at the initial wall thickness t ₀ = 11.12 mm to t ₁ = 6.5 mm with a degree of deformation E ₁ = 41.6%.

до t₂=2,2 мм со степенью деформации Е₂=66,1%.At the second transition, a periodic profile is rotationally drawn in the form of alternating thickenings and thinning with a thickness

to t ₂ = 2.2 mm with a degree of deformation E ₂ = 66.1%.

.Total degree of deformation

.

, что соответствует формуле изобретения Е₂=(0,6÷0,9)Е_Σ.

that corresponds to the claims E ₂ = (0.6 ÷ 0.9) E _Σ .

At the first transition S ₁ = 110 min ^-1 , F _oc1 = 140 mm / min, at the second transition S ₂ = 100 min ^-1 , F _oc2 = 130 mm / min.

S ₂ / S ₁ = _100/110 = 0.9, F _oc2 / F _oc1 = _130/140 = 0.93, which corresponds to the claims: F ₂ = (0.6 ÷ 0.99) F ₁ , S ₂ = (0.6 ÷ 0.99) S ₁ .

At the first transition S ₁ / F _oc1 = _110/140 = 0.785 (mm ^-1 ), at the second transition

S ₂ / F _oc2 = _100/130 = 0.769 (mm ^-1 ), which corresponds to the claims: S / F = (0.6 ÷ 0.95) mm ^-1 .

The formation of internal thickening is carried out in the same way as in example 1.

The ratio of the degrees of deformation and the processing modes when receiving internal thickenings, the ratio of the modes of rotational drawing in the inlet and outlet sections of the rollers and in the main processing section, the ratio of the gaps between the inner surface of the workpiece and the mandrel, the trajectory of the rollers at the entrance and exit, the ratio of the sizes of the profile of the rollers, see example 1.

The implementation of the method of rotational drawing of thin-walled shells in accordance with the invention provides the possibility of manufacturing thin-walled parts of cylindrical and complex shapes with external, internal and end thickenings and parts with a periodic profile with high quality surface finish, geometric shape accuracy and high metal utilization.

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 shells by the proposed method is scheduled.

Claims (7)

1. The method of rotational drawing of thin-walled shells with thickenings, including installing the tube stock on the mandrel, fixing it on the mandrel and shaping it when exposed to deforming rollers in one or more transitions, characterized in that the shaping of the tubular workpiece is carried out in the main and mating sections, in sections with external and internal thickenings and in the sections of the entrance and exit of the deforming rollers, which move on the sections of the entrance along the path in the form of convex-concave circular arcs, and on the site x exit - in the form of concave-convex circular arcs, the angle of inclination of the tangent to the circular arcs in the inflection zone is set within 5-30 °, the shape change in the mating sections of the pipe billet is carried out along the radius of at least one wall thickness of the pipe billet, and the shape is changed thickenings of the tubular billet is carried out with rollers with a profile of the working surface in the form of a combination of conical, toroidal and cylindrical sections, the length of the cylindrical section and the radius of the toroidal section, respectively, p 0.2–0.6 and 0.4–0.8 times the wall thickness of the tube billet, while the gaps between the inner surface of the tube billet and the mandrel during the shaping of the external and internal thickenings are set, respectively, (0.01 ÷ 0.1 ) t ₀ and (0.15 ÷ 0.5) t ₀ , where t _{0 (mm)} is the wall thickness of the pipe billet. 2. The method according to claim 1, characterized in that the shaping of the pipe billet at the inlet and outlet sections of the rollers is performed with a feed rate and rotation speed of 10 ÷ 20% of the feed rate and rotation speed in the main section. 3. The method according to claim 1, characterized in that the shaping of the pipe billet at the last transition when thinning the wall is carried out with a degree of deformation of 0.6 ÷ 0.9 of the total degree of deformation. 4. The method according to any one of claims 1 and 3, characterized in that the shaping of the tube stock at the last transition is performed with a feed rate and a workpiece rotation speed of 0.6 ÷ 0.99 feed rate and rotation speed at previous transitions. 5. The method according to claim 1, characterized in that the shaping of the pipe billet in the mating sections is carried out with a speed and feed of 0.5 ÷ 0.75 speed and feed in the main section. 6. The method according to claim 1, characterized in that the shaping of the internal thickenings of the pipe billet is carried out with a degree of deformation during thinning of the wall, comprising 0.1 ÷ 0.4 of the total degree of deformation of the main section. 7. The method according to claim 1, characterized in that the shaping of the internal thickenings of the pipe billet is carried out with a feed rate and a rotation speed of 0.5 ÷ 0.9 feed rate and rotation speed at previous transitions.

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