A multi-stage twist forming device and process

Abstract

The present invention discloses a multi-stage twisting forming device, including a lower template, an upper pressure head, and a fixed lifting and positioning mechanism; a clamping and twisting mechanism that rotates synchronously with the lower template is arranged above the lower template, and a clamping and fixing mechanism is arranged above the clamping and twisting mechanism in parallel and at a fixed distance; a lifting annular plate is movably clamped between the clamping and twisting mechanism and the clamping and fixing mechanism, and the top surface of the lifting annular plate is fixedly connected with a first radial positioning mechanism; a lifting mounting seat is vertically slidably connected to the outer surface of the lower template, and a second radial positioning mechanism is fixedly installed on the top surface of the lifting mounting seat, and a support plate is fixedly connected to the edge bottom of the lifting annular plate. The present invention realizes single-stage segmented clamping and twisting deformation of a column blank by adopting a clamping and twisting mechanism and a clamping and fixing mechanism, realizes sequential forming of different local forming sections by progressive advancement of the clamping mechanism, and realizes overall deformation of the column blank by incremental superposition of twisting deformation, thereby simplifying the fixture structure and forming process.

Description

Technical Field

[0001] The invention relates to the technical field of plastic forming of metal materials, and in particular to a multi-stage twisting forming device and process. Background Art

[0002] High pressure torsion (HPT) is a plastic processing technology with large deformation. It has a significant effect on grain refinement and can refine the internal structure of the material to submicron, nanometer or even amorphous state. Compared with other preparation technologies for nanocrystalline metal materials, HPT technology can obtain block products with no internal pollution and high density, which is of great significance for the intrinsic research of nanocrystalline metal material properties and industrial applications. HPT involves a relatively high hydrostatic pressure, which inhibits the formation of cracks during deformation, so there is almost no limit to the applicable strain. In addition, compared with other severe plastic deformation processes, the HPT process is also quite simple, the processing results are reliable and cost-effective. However, the disadvantage is that the thickness dimension of the sample that can be processed by HPT is very small. The thickness of the processed disk sample is often only 1mm or even thinner. For a long time, the sample size was limited to a sample size of about 10 mm in diameter. When the height-to-diameter ratio (t / d) of the HPT disk is too large, cross-thickness inhomogeneity may occur. This is the result of excessive strain localization, which can be caused by selecting a specimen with a large height-to-diameter ratio, and this localization is amplified when metals or alloys (such as pure magnesium and various aluminum alloys) exhibit a high tendency to localize deformation. From a technical point of view, the diameter of the HPT specimen can be moderately expanded while following basic design guidelines, but the axial inhomogeneity problem severely limits the size of the specimen in one dimension.

[0003] In order to overcome this problem, some scholars have proposed incremental high-pressure torsion technology, which can achieve high-pressure torsion treatment of the entire billet by superimposing multiple levels of torsion increments, and can produce large samples with ultrafine or nanocrystalline microstructures in three dimensions. It has been applied to pure copper samples with a length of 70 mm and a diameter of 50 mm. However, the main disadvantage of this technical process is that it takes too much time to process the material, and the mold needs to be disassembled in each moving step. In addition, its mold has poor applicability to the size of the billet, and the industrialization cost is high, which is not convenient for large-scale application. Summary of the invention

[0004] The technical problem to be solved by the present invention is: to provide a multi-stage torsion forming device and its preparation process, by adopting a clamping torsion mechanism and a clamping fixing mechanism to realize single-stage segmented clamping and torsion deformation of the column blank, by progressively realizing the switching of different single-stage segmented clamping positions, so as to realize the overall deformation of the column blank by incrementally superimposing torsion deformation, so as to solve the shortcomings of the existing incremental high-pressure torsion technology (IHPT) in which the high-pressure torsion treatment of the overall blank is realized by superposition of multi-stage torsion increments, such as complex equipment and process flow, multiple disassembly and assembly of the mold, and poor size compatibility of the column blank.

[0005] In order to solve the above technical problems, a technical solution adopted by the present invention is:

[0006] A multi-stage twist forming device comprises a lower template fixedly connected to the center of the top surface of the rotating table of the twisting device, an upper pressure head fixedly connected to the power output end of the hydraulic press of the twisting device and suspended directly above the lower template, and a lifting and positioning mechanism fixedly arranged on the top surface of the working table of the twisting device and located outside the lower template. The column blank to be twisted and formed is fixedly clamped between the top surface center of the lower template and the bottom surface of the upper pressure head, and the upper pressure head applies downward pressure to the column blank and maintains the pressure.

[0007] A clamping and twisting mechanism is arranged above the lower template and rotates synchronously with the lower template. The clamping and twisting mechanism is composed of a plurality of clamping and twisting plates evenly distributed around the axis of the lower template. A clamping and fixing mechanism is arranged above the clamping and twisting mechanism in parallel and at a fixed distance. The clamping and fixing mechanism is composed of a plurality of clamping and fixing plates evenly distributed around the axis of the lower template.

[0008] The clamping and twisting mechanism and the clamping and fixing mechanism movably clamp a lifting annular plate fixedly connected to the top output end of the lifting and positioning mechanism, and the lifting and positioning mechanism drives the lifting annular plate to step vertically advance, and the top surface of the lifting annular plate is fixedly connected to a first radial positioning mechanism corresponding to the clamping and fixing plate, and the power output end of the first radial positioning mechanism is fixedly connected to the outer side surface of the clamping and fixing plate, and each first radial positioning mechanism drives the corresponding clamping and fixing plate to approach / move away from the column blank to clamp / release the upper part of the column blank;

[0009] A lifting mounting seat corresponding to the clamping and torsion plate is vertically slidably connected to the outer side surface of the lower template, and a second radial positioning mechanism is fixedly installed on the top surface of the lifting mounting seat. The power output end of the second radial positioning mechanism is fixedly connected to the outer side surface of the clamping and torsion plate, and each second radial positioning mechanism drives the corresponding clamping and fixing plate to approach / move away from the column blank to clamp / release the lower part of the column blank. The edge bottom of the lifting annular plate is fixedly connected to a support plate corresponding to the lifting mounting seat, and the top bottom surface of the lifting mounting seat is movably overlapped on the top surface of the support plate.

[0010] Furthermore, a plurality of vertically arranged guide columns are fixedly connected to the top surface of the lower template, and an upper template coaxially rotatably sleeved on the outer side of the upper pressure head is sleeved on the outer side of the top of the guide column.

[0011] Furthermore, a first guide column travel groove distributed along the radial direction of the lower template is opened in the middle part of the clamping and torsion plate, a second guide column travel groove distributed along the radial direction of the lower template and a circumferential travel groove connected to the second guide column travel groove are opened in the middle part of the clamping and fixing plate, and the guide column moves through the first guide column travel groove and the second guide column travel groove.

[0012] Furthermore, the clamping surface contour shape formed by the inner side surfaces of the plurality of clamping and torsion plates / clamping and fixing plates matches the cross-sectional contour shape of the column blank.

[0013] Furthermore, a vertically arranged guide groove is provided on the outer side surface of the lower template, and a guide strip which is slidably matched with the guide groove is fixedly provided on the inner side surface of the lifting mounting seat.

[0014] Furthermore, a single secondary advancement stroke of the step-by-step vertical advancement of the lifting annular plate is equal to a vertical distance between the bottom surface of the clamping and twisting mechanism and the top surface of the clamping and fixing mechanism.

[0015] A multi-stage twist forming process is also provided, which is applied to the multi-stage twist forming device as described above, and the twist forming process comprises the following steps:

[0016] S1. Billet extrusion treatment: the initial billet is subjected to extrusion shaping treatment through an extrusion die to obtain a columnar billet of a rod-like structure with a preset cross-sectional shape and length;

[0017] S2, mechanism position initialization: the lifting and positioning mechanism drives the lifting annular plate to descend to the lowest position, so that the bottom surface of the clamping and twisting mechanism is located on the top surface of the lower template, each first radial positioning mechanism drives the corresponding clamping and fixing plate to move horizontally to the outermost position, and each second radial positioning mechanism drives the corresponding clamping and fixing plate to move horizontally to the outermost position;

[0018] S3, blank positioning and clamping: the extruded column blank is placed between the upper ram and the lower mold plate, each first radial positioning mechanism drives the corresponding clamping plate close to the column blank to clamp the upper part of the column blank, each second radial positioning mechanism drives the corresponding clamping plate close to the column blank to clamp the lower part of the column blank, the upper ram moves downward to press the column blank and maintain the pressure;

[0019] S4, single-stage torsion deformation: the rotating table of the torsion equipment drives the lower template and the clamping torsion mechanism to rotate synchronously in the forward direction at a preset torsion amount and torsion speed, and the clamping torsion mechanism and the clamping fixing mechanism rotate relative to each other to cause torsion shear deformation of the part of the blank segment clamped therebetween;

[0020] S5, clamping mechanism step operation: after the previous twisting forming is completed, the clamping and fixing mechanism and the clamping and twisting mechanism unload the column blank, the lifting and positioning mechanism drives the lifting ring plate to move upward for a preset step-by-step process, the rotating table of the twisting equipment drives the lower template and the clamping and twisting mechanism to rotate in the opposite direction to achieve circumferential reset, and then the clamping and fixing mechanism and the clamping and twisting mechanism clamp the column blank again;

[0021] S6, multi-stage torsion superposition: repeat the single-stage torsion deformation process of step S4 and step S5, and superimpose the torsion deformation areas of each stage in sequence until the torsion deformation process of the column blank is completed as a whole.

[0022] S7. Take out the torsion sample: the rotating table of the torsion equipment stops rotating, the clamping and fixing mechanism and the clamping and torsion mechanism unload the torsion formed part, the power output end of the hydraulic press of the torsion equipment drives the upper pressure head upward and resets, and the torsion formed part is taken out of the multi-stage torsion forming device for subsequent process processing and obtaining the final formed part.

[0023] Furthermore, the axial pressure exerted on the column blank by the upper pressure head at the power output end of the hydraulic press of the torsion equipment is 0.8-1.0 GPa. For column blanks of different specifications, it should be ensured that the column blank is subjected to hydrostatic pressure without axial instability.

[0024] Furthermore, during the single-stage torsional deformation process, the angle of torsion of the lower template driven by the rotating table does not exceed 20°, and the torsion speed does not exceed 0.35 rad / min.

[0025] Furthermore, the preset single-stage travel distance of the upward movement of the lifting annular plate is 5-10 mm, and the single-stage travel distance is the axial single-stage torsion length of the column blank.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] The present invention connects the upper pressure head to the power output end of the hydraulic press of the torsion device, and cooperates with the lower template fixedly connected to the rotating table of the torsion device, so as to apply axial pressure to the column blank, so as to ensure that the column blank as a whole is subjected to sufficient axial hydrostatic pressure, so that the formability of the material is improved, and the blank is kept axially stable when torsion, and the tangential cumulative shear deformation of the blank is increased, which has a significant grain refinement effect;

[0028] By setting a clamping and twisting mechanism and a clamping and fixing mechanism, the clamping of the two ends of the local forming section of the columnar blank is achieved. The lower template and the clamping and twisting mechanism are driven to rotate synchronously by a rotating disk, so that the clamping and twisting mechanism and the clamping and fixing mechanism rotate relative to each other, so that the locally clamped single-stage deformation section completes the single-stage torsional shear deformation; by setting a lifting annular plate driven by a lifting and positioning mechanism, the clamping mechanism is advanced step by step with a fixed distance, and the multi-stage local torsional superposition of each single-stage deformation section is achieved. By controlling the deformation amount of each single-stage deformation section, the uniform torsional deformation of the column blank in the axial length direction or the segmented differential torsional deformation of different axial lengths and different torsional angles can be achieved;

[0029] The present invention controls the superposition of multi-stage local torsion to achieve the overall torsion deformation of the column blank, which can adapt to the clamping and forming requirements of column blanks with different axial lengths. By adopting two radial positioning mechanisms, the clamping and releasing of the column blank by the clamping torsion mechanism and the clamping and fixing mechanism are respectively achieved, which is convenient for adapting to the clamping requirements of column blanks with different outer diameters. Therefore, it has good versatility for column blanks with various cross-sectional shapes, different axial lengths and different outer diameters.

[0030] Compared with the traditional segmented transmission mechanism of the segmented tightly surrounded mold, the present invention adopts a clamping and twisting mechanism and a clamping and fixing mechanism to realize the clamping and twisting deformation of the single-stage forming segment, and realizes the sequential forming of different local forming segments through the progressive clamping mechanism, which is convenient for realizing automatic control, simplifies the clamp structure and the forming process, thereby simplifying the overall structure of the twisting device and reducing the cost of industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention from a top view angle;

[0032] Figure 2 It is a schematic diagram of the three-dimensional structure of the present invention from an upward viewing angle;

[0033] Figure 3 It is a schematic diagram of the top view of the structure of the present invention;

[0034] Figure 4 for Figure 3 Schematic diagram of the cross-sectional structure at AA in the middle;

[0035] Figure 5 It is a three-dimensional structural schematic diagram of the column blank in a clamping state;

[0036] Figure 6 is a schematic diagram of the three-dimensional structure of the clamping and twisting plate;

[0037] Figure 7 is a schematic diagram of the three-dimensional structure of the clamping and fixing plate;

[0038] Figure 8 It is a schematic diagram of the single-stage twisting process of the present invention;

[0039] Fig. 9 It is a schematic diagram of the progressive process of the clamping mechanism of the present invention.

[0040] In the figure: 1. lower template; 2. upper pressure head; 3. clamping and torsion plate; 301. first guide column travel groove; 4. clamping and fixing plate; 401. second guide column travel groove; 402. circumferential travel groove; 5. lifting annular plate; 6. lifting and positioning mechanism; 7. first radial positioning mechanism; 8. lifting mounting seat; 9. second radial positioning mechanism; 10. support plate; 11. guide column; 12. upper template; 100. column blank. DETAILED DESCRIPTION

[0041] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0042] It should be noted that when a component is referred to as being "mounted on" another component, it may be directly on the other component or there may be a central component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a central component at the same time. When a component is considered to be "fixed to" another component, it may be directly fixed on the other component or there may be a central component at the same time.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "or / and" used herein includes any and all combinations of one or more of the related listed items.

[0044] The multi-stage torsion forming device of the present invention is directly applied to the existing torsion equipment (such as a high-pressure torsion forming test machine) to provide the required hydrostatic pressure and torsion force for torsion forming.

[0045] See also Figures 1 to 9The multi-stage twist forming device comprises a lower template 1 fixedly connected to the center of the top surface of the rotating table of the twisting device, an upper pressure head 2 fixedly connected to the power output end of the hydraulic press of the twisting device and suspended directly above the lower template 1, and a lifting and positioning mechanism 6 fixedly arranged on the top surface of the working table of the twisting device and located outside the lower template 1. The column blank 100 to be twisted and formed is fixedly clamped between the top surface center of the lower template 1 and the bottom surface of the upper pressure head 2. The upper pressure head 2 applies downward pressure to the column blank 100 and maintains the pressure to ensure that the column The blank 100 can withstand sufficient axial hydrostatic pressure, which on the one hand improves the material formability, and on the other hand allows the column blank 100 to maintain axial stability when twisted, increasing the tangential cumulative shear deformation of the column blank 100, which has a significant grain refinement effect. At the same time, in the subsequent clamping mechanism advancement process, the clamping position of the column blank 100 is kept unchanged while the clamping mechanism and the column blank 100 are in a non-contact state, so as to ensure that the clamping effect of the column blank 100 at both ends of each torsional deformation section is the same.

[0046] A clamping and twisting mechanism is arranged above the lower template 1 and rotates synchronously with the lower template 1. The clamping and twisting mechanism is composed of a plurality of clamping and twisting plates 3 uniformly distributed circumferentially around the axis of the lower template 1. A clamping and fixing mechanism is arranged above the clamping and twisting mechanism in parallel and at a fixed distance. The clamping and fixing mechanism is composed of a plurality of clamping and fixing plates 4 uniformly distributed circumferentially around the axis of the lower template 1. In this embodiment, the number of the clamping and twisting plates 3 and the number of the clamping and fixing plates 4 are both 4, and they are fan-shaped plate structures with the same outer contour. In any torsional deformation section of the column blank 100, the bottom end of the torsional deformation section is clamped by each clamping torsion plate 3, and the top end of the torsional deformation section is clamped by each clamping and fixing plate 4, that is, the clamping torsion mechanism and the clamping and fixing mechanism clamp the two ends of the torsional deformation section respectively, and then the clamping torsion mechanism and the clamping and fixing mechanism are relatively rotated around the axis of the column blank 100. Under the action of the hydrostatic pressure provided by the upper pressure head 2, the torsional deformation section can be sheared by the friction between the clamping torsion mechanism and the column blank 100, and the friction between the clamping and fixing mechanism and the column blank 100, thereby realizing local torsion of the corresponding section.

[0047] Preferably, a plurality of (4 in the present embodiment) vertically arranged guide columns 11 are fixedly connected to the top surface of the lower template 1, and an upper template 12 is sleeved on the outer side of the top of the guide column 11 and is coaxially rotatably sleeved on the outer side of the upper press head 2, so that the upper template 12 can rotate synchronously and coaxially with the lower template 1, and through the rotational coordination of the upper template 12 and the upper press head 2, the relative rotation between the lower template 1 and the upper press head 2 is realized, which constructs the forming conditions for the torsional deformation of each torsional deformation segment of the column blank 100, and can also ensure the coaxiality of the lower template 1 and the upper press head 2. In this embodiment, the upper part of the upper pressure head 2 is a cylinder and the lower part is a disc with a flange structure. A circular groove is provided at the center of the bottom surface of the upper template 12, and a through hole is provided at the center of the center groove. The cylinder of the upper pressure head 2 passes through the through hole of the upper template 12, and the disc of the upper pressure head 2 is embedded in the circular groove of the upper template 12, so that the upper template 12 can be movably overlapped on the upper pressure head 2; and the outer diameter of the disc is not greater than the inner diameter of the center groove, and the outer diameter of the cylinder is not greater than the aperture of the through hole. The top surface of the disc and the bottom surface of the circular groove are paired with annular ball grooves, and a number of balls are arranged in the ball grooves, which ensures that the upper template 12 and the upper pressure head 2 are coaxially rotated relative to each other, and also makes the relative rotation between the two smoother. Obviously, the rotational cooperation between the upper template 12 and the upper pressure head 2 can also be achieved by other mechanical assembly methods such as rolling bearings to achieve rotational connection.

[0048] Furthermore, the clamping surface contour formed by the inner side surfaces of the plurality of clamping and twisting plates 3 / clamping and fixing plates 4 matches the cross-sectional contour of the column blank 100. In this way, the clamping and twisting mechanism and the clamping and fixing mechanism can clamp column blanks of various cross-sectional shapes. For example, when the column blank 100 is a cylinder, the inner side surface of the clamping and twisting plate 3 / clamping and fixing plate 4 is an arc-shaped concave surface, and the arc-shaped concave surfaces of the four clamping and twisting plates 3 / clamping and fixing plates 4 can form a circular enclosing surface matching the cylindrical surface; when the column blank 100 is a square-section cylinder, the inner side surface of the clamping and twisting plate 3 / clamping and fixing plate 4 is a V-shaped concave surface, and the angle between the two side surfaces of the V-shape is 90°, and the V-shaped concave surfaces of the four clamping and twisting plates 3 / clamping and fixing plates 4 can form a square enclosing surface matching the corner position of the column surface, or the inner side surface of the clamping and twisting plate 3 / clamping and fixing plate 4 is a plane, and the inner side planes of the four clamping and twisting plates 3 / clamping and fixing plates 4 can form square enclosing surfaces respectively matching the column surface.

[0049] The lifting annular plate 5 fixedly connected to the top output end of the lifting and positioning mechanism 6 is movably clamped between the clamping and twisting mechanism and the clamping and fixing mechanism, and the lifting and positioning mechanism 6 drives the lifting annular plate 5 to step vertically. In this embodiment, the lifting and positioning mechanism 6 adopts an electric cylinder driven by a servo motor to achieve continuous fixed-length output at its power output end. After a certain torsional deformation section of the column blank 100 completes a single-stage torsional deformation (local torsional deformation), the lifting and positioning mechanism 6 drives the lifting annular plate 5 to move vertically upward by a preset step-by-step process, so that the clamping and twisting mechanism and the clamping and fixing mechanism synchronously rise the corresponding step-by-step process, and then re-clamp the unformed section above the torsional deformation section, and then complete the torsional deformation process of the re-clamped torsional deformation section through the relative rotation of the clamping and twisting mechanism and the clamping and fixing mechanism. Since the clamping and twisting mechanism and the lower mold plate 1 rotate synchronously during the torsional deformation process, that is, they do not rotate relative to each other, the torsional deformation segment between the two will not undergo secondary torsional deformation; at the same time, since the clamping and fixing mechanism and the upper pressure head 2 are both kept in a fixed state, the unformed segment between the two will not undergo torsional deformation. By gradually advancing the clamping mechanism, the corresponding torsional deformation segments are clamped and torsional deformed, and the local segments of the column blank 100 are successively torsion-formed, thereby completing the overall torsional deformation of the column blank 100 by superposition.

[0050] Preferably, the single secondary travel of the step-by-step vertical advancement of the lifting annular plate 5 is equal to the vertical spacing between the bottom surface of the clamping and twisting mechanism and the top surface of the clamping and fixing mechanism, so that each torsional deformation segment can be continuously connected without overlap and interruption. By changing the thickness of the inner edge of the lifting annular plate 5, or by fixing an adjustment gasket on the inner edge surface of the lifting annular plate 5, the vertical spacing between the bottom surface of the clamping and twisting mechanism and the top surface of the clamping and fixing mechanism can be adjusted, that is, the single secondary travel can be adjusted, and then by setting the single rise distance of the output end of the lifting and positioning mechanism 6, it is matched with the adjusted single secondary travel, so as to meet the graded superposition torsion forming of column blanks 100 with different axial lengths.

[0051] The top surface of the lifting annular plate 5 is fixedly connected with a first radial positioning mechanism 7 corresponding to the clamping and fixing plate 4. The power output end of the first radial positioning mechanism 7 is fixedly connected to the outer side surface of the clamping and fixing plate 4. Each first radial positioning mechanism 7 drives the corresponding clamping and fixing plate 4 to approach / move away from the column blank 100 to clamp / release the upper part of the column blank 100. Specifically, the first radial positioning mechanism 7 adopts a three-axis cylinder, and its output shaft end is fixedly connected to the outer side surface of the clamping and fixing plate 4 through a connecting plate. In this embodiment, a total of four groups of lifting and positioning mechanisms 6 are arranged, which are evenly arranged on the bottom surface of the lifting annular plate 5 and work synchronously. Therefore, the lifting annular plate 5 is driven by the four groups of lifting and positioning mechanisms 6 to maintain vertical lifting in a horizontal state, and no axial rotation occurs during the lifting process and after vertical positioning, thereby ensuring that the circumferential relative position of the clamping and fixing plate 4 and the column blank 100 remains unchanged, and only vertical relative movement occurs during the progressive process.

[0052] The outer surface of the lower template 1 is vertically slidably connected with a lifting mount 8 corresponding to the clamping and torsion plate 3, and the top surface of the lifting mount 8 is fixedly installed with a second radial positioning mechanism 9, and the power output end of the second radial positioning mechanism 9 is fixedly connected to the outer side surface of the clamping and torsion plate 3. Each second radial positioning mechanism 9 drives the corresponding clamping and fixing plate 4 to approach / move away from the column blank 100 to clamp / release the lower part of the column blank 100. Specifically, the second radial positioning mechanism 9 also adopts a three-axis cylinder, and its output shaft end is fixedly connected to the outer side surface of the clamping and torsion plate 3 through a connecting plate. A vertically arranged guide groove is provided on the outer side surface of the lower template 1, and a guide strip which slides with the guide groove is fixedly provided on the inner side surface of the lifting mounting seat 8. Through the sliding cooperation between the guide strip and the guide groove, the lifting mounting seat 8 and the second radial positioning mechanism 9 fixedly connected thereto and the lower template 1 can only move vertically relative to each other while maintaining the circumferential relative position unchanged. Therefore, in the process of relative rotation between the lower template 1 and the upper pressure head 2, the clamping and torsion mechanism and the lower template 1 realize synchronous rotation, and under the condition that the circumferential position of the clamping and fixing mechanism remains unchanged, the torsion deformation of the torsion deformation section clamped between the clamping and torsion mechanism and the clamping and fixing mechanism is realized.

[0053] The bottom edge of the lifting ring plate 5 is fixedly connected with a support plate 10 corresponding to the lifting mounting seat 8, and the top bottom surface of the lifting mounting seat 8 is movably overlapped on the top surface of the support plate 10. In this way, the lifting mounting seat 8 and the second radial positioning mechanism 9 fixed thereon can be lifted and lowered synchronously during the lifting and lowering process of the lifting ring plate 5 through the supporting effect of the support plate 10 on the lifting mounting seat 8, so that the clamping and twisting mechanism and the clamping and fixing mechanism can be lifted and lowered synchronously; and because the bottom surface of the lifting mounting seat 8 and the top surface of the support plate 10 are in sliding contact, there will be no motion interference with the circumferential relative rotation between the lower template 1 and the lifting ring plate 5.

[0054] A first guide post travel groove 301 distributed along the radial direction of the lower template 1 is provided in the middle of the clamping and torsion plate 3, a second guide post travel groove 401 distributed along the radial direction of the lower template 1 and a circumferential travel groove 402 connected to the second guide post travel groove 401 are provided in the middle of the clamping and fixing plate 4, and the guide post 11 movably penetrates the first guide post travel groove 301 and the second guide post travel groove 401. The first guide post travel groove 301 is a waist-shaped through hole, and the outer side surface of the guide post 11 is slidably fitted with the side surface of the waist-shaped through hole, which can guide the radial horizontal movement of the clamping and torsion plate 3. At the same time, the length of the waist-shaped through hole is not less than the output shaft end stroke of the second radial positioning mechanism 9, so as to meet the clamping needs of column blanks 100 with different outer diameters. In this embodiment, the second guide column stroke groove 401 has the same size specifications as the first guide column stroke groove 301, and the angle between the side wall of the circumferential stroke groove 402 and the side wall of the second guide column stroke groove 401 is not less than the single-stage torsion angle of the torsional deformation section of the column blank 100, that is, the circumferential rotation angle of the lower template 1 driven by the rotating table of the torsion equipment at a single time. The setting of the circumferential stroke groove 402 enables the guide column 11 to move freely inside the clamping fixed plate 4 while the guide column 11 follows the rotation of the lower template 1.

[0055] The present invention also provides a multi-stage twist forming process, which is applied to the multi-stage twist forming device as described above. The twist forming process includes the following steps:

[0056] S1. Billet extrusion processing: The initial billet is subjected to extrusion shaping processing through an extrusion die to obtain a columnar billet 100 of a rod-like structure with a preset cross-sectional shape and length.

[0057] S2. Initialization of mechanism position: the lifting and positioning mechanism 6 drives the lifting annular plate 5 to descend to the lowest position, so that the bottom surface of the clamping and twisting mechanism is located on the top surface of the lower template 1, and each first radial positioning mechanism 7 drives the corresponding clamping and fixing plate 4 to move horizontally to the outermost position, and each second radial positioning mechanism 9 drives the corresponding clamping and fixing plate 4 to move horizontally to the outermost position.

[0058] S3, blank positioning and clamping: the extruded column blank 100 is placed between the upper ram 2 and the lower mold plate 1, each first radial positioning mechanism 7 drives the corresponding clamping and fixing plate 4 close to the column blank 100 to clamp the upper part of the column blank 100, each second radial positioning mechanism 9 drives the corresponding clamping and fixing plate 4 close to the column blank 100 to clamp the lower part of the column blank 100, and the upper ram 2 moves downward to press and maintain the column blank 100. Preferably, the axial pressure exerted on the column blank 100 by the power output end of the hydraulic press of the torsion equipment through the upper ram 2 is 0.8-1.0GPa. For column blanks 100 of different specifications, the magnitude of the axial pressure is suitable to ensure that the column blank 100 is subjected to hydrostatic pressure without axial instability.

[0059] S4. Single-stage torsional deformation: The rotating table of the torsional equipment drives the lower template 1 and the clamping torsional mechanism to rotate synchronously in the forward direction at a preset torsional amount and torsional speed. The clamping torsional mechanism and the clamping fixing mechanism rotate relative to each other to cause torsional shear deformation of the partial billet segment clamped therebetween. Preferably, during the single-stage torsional deformation process, the rotating table drives the lower template 1 to twist at an angle not exceeding 20°, and the twisting speed does not exceed 0.35 rad / min, so as to enhance the grain refinement effect.

[0060] S5, clamping mechanism step operation: after the previous torsion forming is completed, each first radial positioning mechanism 7 drives the corresponding clamping and fixing plate 4 away from the column blank 100 to release the column blank 100, each second radial positioning mechanism 9 drives the corresponding clamping and fixing plate 4 away from the column blank 100 to release the column blank 100, the clamping and fixing mechanism and the clamping and twisting mechanism unload the column blank 100, the lifting and positioning mechanism 6 drives the lifting and lifting annular plate 5 to move upward by a preset step stroke, the rotating table of the torsion equipment drives the lower template 1 and the clamping and twisting mechanism to rotate in the opposite direction to achieve circumferential reset, and then the clamping and fixing mechanism and the clamping and twisting mechanism clamp the column blank 100 again. The preset single-stage stroke of the lifting and lifting annular plate 5 moving upward is 5-10mm. In this embodiment, the preset single-stage stroke is 5mm, that is, the axial single-stage torsion length of the column blank 100 is 5mm.

[0061] S6, multi-stage twisting superposition: repeat the single-stage twisting deformation process of step S4 and step S5, and stack the twisting deformation areas of each stage in sequence until the column blank 100 completes the twisting deformation process as a whole. In order to ensure that each twisting deformation section is continuously connected, it is preferred that the overall length of the column blank 100 is an integer multiple of the preset single-stage process.

[0062] S7. Take out the torsion sample: the rotating table of the torsion equipment stops rotating, the clamping and fixing mechanism and the clamping and torsion mechanism unload the torsion formed part, the power output end of the hydraulic press of the torsion equipment drives the upper pressure head 2 upward and resets, and the torsion formed part is taken out from the multi-stage torsion forming device for subsequent process processing and obtaining the final formed part.

[0063] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A multi-stage twist forming device, characterized in that: It comprises a lower template (1) fixedly connected to the center of the top surface of the rotating table of the twisting device, an upper pressure head (2) fixedly connected to the power output end of the hydraulic press of the twisting device and suspended directly above the lower template (1), and a lifting and positioning mechanism (6) fixedly arranged on the top surface of the working table of the twisting device and located outside the lower template (1); a column blank (100) to be twisted and formed is fixedly clamped between the center of the top surface of the lower template (1) and the bottom surface of the upper pressure head (2); the upper pressure head (2) applies downward pressure to the column blank (100) and maintains the pressure; A clamping and twisting mechanism is arranged above the lower template (1) and rotates synchronously with the lower template (1), the clamping and twisting mechanism is composed of a plurality of clamping and twisting plates (3) uniformly distributed circumferentially around the axis of the lower template (1), and a clamping and fixing mechanism is arranged above the clamping and twisting mechanism in parallel and at a fixed distance, the clamping and fixing mechanism is composed of a plurality of clamping and fixing plates (4) uniformly distributed circumferentially around the axis of the lower template (1); A lifting annular plate (5) fixedly connected to the top output end of the lifting and positioning mechanism (6) is movably clamped between the clamping and twisting mechanism and the clamping and fixing mechanism. The lifting and positioning mechanism (6) drives the lifting annular plate (5) to step vertically advance. The top surface of the lifting annular plate (5) is fixedly connected to a first radial positioning mechanism (7) corresponding to the clamping and fixing plate (4). The power output end of the first radial positioning mechanism (7) is fixedly connected to the outer side surface of the clamping and fixing plate (4). Each first radial positioning mechanism (7) drives the corresponding clamping and fixing plate (4) to approach / move away from the column blank (100) to clamp / release the upper part of the column blank (100). A lifting mounting seat (8) corresponding to the clamping and twisting plate (3) is vertically and slidably connected on the outer surface of the lower template (1); a second radial positioning mechanism (9) is fixedly installed on the top surface of the lifting mounting seat (8); a power output end of the second radial positioning mechanism (9) is fixedly connected to the outer side surface of the clamping and twisting plate (3); each second radial positioning mechanism (9) drives the corresponding clamping and fixing plate (4) to approach / move away from the column blank (100) to clamp / release the lower part of the column blank (100); a support plate (10) corresponding to the lifting mounting plate (8) is fixedly connected to the edge bottom of the lifting annular plate (5); and the top bottom surface of the lifting mounting plate (8) is movably overlapped on the top surface of the support plate (10); The synchronous advancement of the clamping and twisting mechanism and the clamping and fixing mechanism realizes the switching of different single-stage segmented clamping positions of the column blank (100) and the local twisting deformation in each clamping segment, and the overall deformation of the column blank (100) is realized by incrementally superimposing the twisting deformation segment by segment.

2. A multi-stage twist forming device according to claim 1, characterized in that: A plurality of vertically arranged guide columns (11) are fixedly connected to the top surface of the lower template (1), and an upper template (12) is sleeved on the outer side of the top of the guide column (11) and is coaxially rotatably sleeved on the outer side of the upper pressure head (2).

3. A multi-stage twist forming device according to claim 2, characterized in that: The clamping and twisting plate (3) has a first guide column travel groove (301) in the middle thereof and is distributed in the radial direction of the lower template (1); the clamping and fixing plate (4) has a second guide column travel groove (401) in the middle thereof and is distributed in the radial direction of the lower template (1); and a circumferential travel groove (402) connected to the second guide column travel groove (401); the guide column (11) is movable and passes through the first guide column travel groove (301) and the second guide column travel groove (401).

4. A multi-stage twist forming device according to any one of claims 1 to 3, characterized in that: The clamping surface contour shape formed by the inner side surfaces of the plurality of clamping and twisting plates (3) / clamping and fixing plates (4) matches the cross-sectional contour shape of the column blank (100).

5. A multi-stage twist forming device according to any one of claims 1 to 3, characterized in that: A vertically arranged guide groove is provided on the outer side surface of the lower template (1), and a guide strip that slidably cooperates with the guide groove is fixedly provided on the inner side surface of the lifting installation plate (8).

6. A multi-stage twist forming device according to any one of claims 1 to 3, characterized in that: The single secondary travel distance of the step-by-step vertical progressive movement of the lifting annular plate (5) is equal to the vertical distance between the bottom surface of the clamping and twisting mechanism and the top surface of the clamping and fixing mechanism.

7. A multi-stage twist forming process, applied to the multi-stage twist forming device as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: S1, billet extrusion processing: the initial billet is subjected to extrusion shaping processing through an extrusion die to obtain a columnar billet (100) of a rod-like structure with a preset cross-sectional shape and length; S2, initialization of mechanism position: the lifting and positioning mechanism (6) drives the lifting and positioning annular plate (5) to descend to the lowest position, so that the bottom surface of the clamping and twisting mechanism is located on the top surface of the lower template (1), each first radial positioning mechanism (7) drives the corresponding clamping and fixing plate (4) to move horizontally to the outermost position, and each second radial positioning mechanism (9) drives the corresponding clamping and fixing plate (4) to move horizontally to the outermost position; S3, blank positioning and clamping: the extruded column blank (100) is placed between the upper ram (2) and the lower mold plate (1), each first radial positioning mechanism (7) drives the corresponding clamping and fixing plate (4) to approach the column blank (100) and clamp the upper part of the column blank (100), each second radial positioning mechanism (9) drives the corresponding clamping and fixing plate (4) to approach the column blank (100) and clamp the lower part of the column blank (100), and the upper ram (2) moves downward to press and maintain the column blank (100); S4, single-stage torsion deformation: the rotating table of the torsion device drives the lower template (1) and the clamping torsion mechanism to rotate synchronously in the forward direction at a preset torsion amount and torsion speed, and the clamping torsion mechanism and the clamping fixing mechanism rotate relative to each other to cause torsion shear deformation of the part of the blank segment clamped therebetween; S5, clamping mechanism step-by-step operation: after the previous torsion forming is completed, the clamping and fixing mechanism and the clamping and twisting mechanism unload the column blank (100), the lifting and positioning mechanism (6) drives the lifting annular plate (5) to move upward for a preset step-by-step process, the rotating table of the torsion device drives the lower template (1) and the clamping and twisting mechanism to rotate in the opposite direction to achieve circumferential reset, and then the clamping and fixing mechanism and the clamping and twisting mechanism clamp the column blank (100) again; S6, multi-stage torsion superposition: repeating the single-stage torsion deformation process of step S4 and step S5, and superimposing the torsion deformation regions of each stage in sequence until the column blank (100) completes the torsion deformation process as a whole; S7. Removing the torsion sample: the rotating table of the torsion device stops rotating, the clamping and fixing mechanism and the clamping and torsion mechanism unload the torsion formed part, the power output end of the hydraulic press of the torsion device drives the upper pressure head (2) upward and resets, and the torsion formed part is removed from the multi-stage torsion forming device for subsequent process processing and obtaining the final formed part.

8. A multi-stage twist forming process according to claim 7, characterized in that: The axial pressure exerted on the column blank (100) by the power output end of the hydraulic press of the torsion device through the upper pressure head (2) is 0.8-1.0 GPa.

9. The multi-stage twist forming process according to claim 7, characterized in that: During the single-stage torsional deformation process, the angle of torsional movement of the lower template (1) driven by the rotating table does not exceed 20°, and the torsional rotation speed does not exceed 0.35 rad / min.

10. The multi-stage twist forming process according to claim 7, characterized in that: The preset single-stage travel distance of the lifting annular plate (5) moving upward is 5-10 mm.

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