CN102189706B - High-pressure shearing deformation method and device for tubular materials - Google Patents

Abstract

The invention discloses a method and device for high-pressure shear deformation of tubular materials. Firstly, the workpiece to be processed is selected, and the workpiece is tubular, and the inner wall and the outer wall of the workpiece are respectively restrained by constraining bodies; then axial pressure is directly applied to the end of the workpiece, so that The workpiece undergoes elastic deformation or slight plastic deformation, and accumulates a hydrostatic pressure of up to 1 to 15GPa in the workpiece; then, a torque is provided to a constraint body in contact with the inner or outer wall of the workpiece to make it rotate around the central axis of the workpiece and fix another constraint at the same time Under the action of the circumferential friction between the restraining body and the inner and outer walls of the workpiece, the materials at different thicknesses in the radial direction inside the workpiece rotate at different angular velocities, thereby realizing the circumferential shear deformation of the workpiece. The invention has high technical feasibility, no special requirements for operation, and the required equipment is simple and easy to obtain. At the same time, because the present invention is a new plastic processing method realized by relying on traditional extrusion equipment, it expands the functions of traditional extrusion equipment.

Description

High-pressure shear deformation method and device for tubular material

technical field

The invention relates to the field of material processing engineering, in particular to a method and device for realizing circumferential shear plastic deformation of tubular materials, which are mainly applied to various metals and alloy materials, inorganic non-metallic materials and polymer materials, etc., to realize these The plastic deformation of the material under high hydrostatic pressure can control and optimize its structure and improve its performance.

Background technique

The severe plastic deformation (SPD) method is a general term for a series of plastic processing techniques with large deformation. The effect of the SPD method on grain refinement is obvious, and the internal structure of the material can be refined to submicron level, nanometer level or even amorphous state [R.Z.Valiev.Nature materials.2004(3):511-516.; R.Z.Valiev, A.K.Mukherjee. Scripta mater. 2001(44): 1747-1750.]. In recent years, the technology of preparing bulk nanostructure materials by SPD method has attracted widespread attention from experts and scholars in the field of materials science. At the same time, a large number of researches have promoted the continuous development of SPD technology in the preparation of bulk ultrafine crystal and nanocrystalline materials. The research team led by R.Z.Valiev of Ufa Aeronautical Technology University in Russia believes that the preparation of ultrafine-grained materials by SPD method should meet a number of conditions [R.Z.Valiev, R.K.Islamgaliev, I V.Alexandrov.Progress in Materials Science.2000(45): 103 -189.], mainly including: large plastic deformation, relatively low deformation temperature and high hydrostatic pressure inside the deformed material. Under the guidance of this principle, various SPD processes and methods have been proposed and developed.

At present, the most concerned SPD methods are mainly accumulative roll-bonding (ARB for short) technology, equal-channel angular pressing (ECAP for short) technology, and high-pressure torsion (high-pressure torsion for short) technology. HPT) technology, etc. Among them, the ARB technology, as shown in Figure 1, can continuously prepare thin-plate ultrafine-grained materials, and is easy to implement on a traditional rolling mill. The equipment is simple and the practical application is of great significance. However, in the process of ARB technology, in order to achieve good rolling compounding, lubricants are often not used, which is detrimental to the service life of the rolls. At the same time, because the hydrostatic pressure that the material can achieve due to the limitation of deformation conditions during the rolling process is not high enough, cracking will occur after a certain amount of deformation is accumulated during the processing [N.Tsuji, Y.Saito, S.H.Lee, et al. al. Advanced Engineering Materials. 2003(5): 338-344.]. ECAP technology is shown in Figure 2, and the use of this technology for ultra-fine-grained metal processing has great potential. However, for some difficult-to-process alloys (such as magnesium alloys, etc.), cracking often occurs during ECAP. If the deformation temperature is increased, it will affect the life of the mold on the one hand, and affect the grain refinement effect on the other hand. In addition, due to the limitation of the mold material, the deformation temperature cannot be increased without limit. Moreover, in order to achieve large cumulative plastic deformation, ECAP requires multi-pass processing, and the operation is complicated. Back pressure ECAP (back pressure equal-channel angular pressing, BP-ECAP for short) is an ECAP technology that applies back pressure to the outlet channel of the mold. Improve the microstructure and mechanical properties of the material; the applied back pressure is limited, and the hydrostatic pressure is generally maintained at several hundred MPa [R.YE.Lapovok.Journal of materials science.2005(40):341-346.]. If the applied back pressure is too high, ECAP cannot be achieved due to factors such as friction and die strength. HPT technology is the most in line with the multiple conditions that should be met in the preparation of ultrafine-grained materials by the SPD method mentioned above. Among the existing SPD technologies, the HPT technology has the strongest grain refinement ability. However, the size of the thickness direction of the sample that can be processed by HPT is very small [A.P.Zhilyaev, T.G.Langdon. Progress in Materials Science. Large strain gradient, uneven deformation, and uneven grain refinement.

Tóth et al [L.S.Tóth, M.Arzaghi, J.J.Fundenberger, B.Beausir: Scr.Mater.Vol.60 (2009), p.175] proposed a high-pressure torsion method for tubular materials (high-pressure tube twisting, HPTT ), as shown in Figure 5, an elastic mandrel is placed inside the tubular sample, a rigid disk is placed outside, and both ends of the sample are fixed with baffles. When the mandrel is pressurized, the radial expansion of the mandrel produces radial pressure on the inner wall of the tubular sample, while the rigid disk produces a radial pressure in the opposite direction on the outer wall of the tubular sample, thereby generating hydrostatic pressure in the tubular sample. At this time, the ring sleeve is rotated, and the tubular sample realizes hoop shear deformation under the action of hoop friction on the surface. The idea of this method is very good, but the main problem is that the method of loading the sample is a radial loading method, that is to say, this method directly applies axial pressure to the mandrel, and the mandrel exerts radial pressure on the sample. to pressure. In this loading mode, the pressure is not directly loaded on the axial direction of the tubular material, and the hydrostatic pressure on the sample comes from the elastic deformation of the mandrel after compression. Since the elastic deformation of the material cannot be very large, it is difficult to produce high Hydrostatic pressure, so the hoop friction that can be provided is limited, and it is only suitable for pure metals with low strength. For materials with higher strength, since the friction force that can be generated cannot reach the yield strength of the material, it is prone to slipping and other phenomena, and the required deformation cannot be achieved.

Another problem with this method is that the baffles located at both ends of the tubular sample are a cantilever beam structure, which does not constrain the axial deformation of the sample enough. When the hydrostatic pressure on the sample is high, the material is easily squeezed out from the gap. , affecting the processing process.

Contents of the invention

The object of the present invention is to provide a new severe plastic deformation method and its device: tube-High Pressure Shearing (t-HPS for short) technology. This technology satisfies many requirements for the preparation of ultrafine-grained materials by SPD method, such as large plastic deformation, relatively low deformation temperature and high hydrostatic pressure inside the deformed material. This method avoids the cumbersome process of ARB, ECAP and back pressure ECAP technologies that require multiple operations. At the same time, due to the essential difference in loading methods, this method also overcomes the problem of insufficient hydrostatic pressure in the HPTT method of Tóth et al. When processing materials, it can provide high hydrostatic pressure conditions similar to HPT technology, so it is suitable for processing difficult-to-deform metals and alloys, so as to control and optimize the structure of materials and improve their performance.

The technical solution to realize the object of the present invention is: a method for high-pressure shear deformation of tubular materials. First, select the workpiece to be processed. The pressure causes the workpiece to undergo elastic deformation or slight plastic deformation, and accumulates high hydrostatic pressure in the workpiece; then, a torque is provided to a constraint body in contact with the inner or outer wall of the workpiece to make it rotate around the central axis of the workpiece while fixing the other constraint body , under the action of the circumferential friction between the restraining body and the inner and outer walls of the workpiece, the materials at different thicknesses in the radial direction inside the workpiece rotate at different angular velocities, thereby realizing the circumferential shear deformation of the workpiece.

A high-pressure shear deformation device for tubular materials, including a press with constant pressure function and a mold with the functions of transmitting pressure, restraining deformation and realizing partial rotation; the mold includes: an upper anvil, a lower anvil, fixed or rotatable The rigid mandrel and the rotatable or fixed rigid ring; the upper anvil and the lower anvil are respectively installed on the upper pressure head and the base of the press, the workpiece is placed between the upper anvil and the lower anvil, and the upper anvil The lower end and the upper end of the lower anvil come into contact with the upper and lower end surfaces of the workpiece through the set bosses. The outer surface is in contact with the inner wall of the workpiece, the outer surface of the workpiece is concentrically provided with a rigid ring, and the inner surface of the rigid ring is in contact with the outer wall of the workpiece.

Compared with the prior art, the present invention has significant advantages: (1) the processing procedure is simple. The t-HPS method proposed by the invention is a severe plastic deformation method that can be realized in a single pass on a traditional extruder with a constant pressure function. In contrast, methods such as the cumulative rolling (ARB) method, multi-directional forging, equal-diameter angular extrusion (ECAP) method, and back pressure ECAP often require many repeated process passes to achieve high-strain plastic deformation, which consumes a lot of manpower. . However, this method utilizes the frictional force between the rigid collar, the tubular workpiece, the mandrel, and the tubular workpiece to rotate the rigid collar and fix the mandrel so that the outer area of the tubular workpiece in contact with the rigid collar is relative to the inner area in contact with the mandrel. Circumferential shear occurs in the layer area, thereby achieving severe plastic deformation under a single process pass. The true value should be 1-10, or even higher. As described in the above technical solution, the t-HPS method proposed by the present invention has a simple principle and easy-to-obtain equipment, and can be realized in a general plastic forming laboratory.

(2) The hydrostatic pressure that can be provided is high, so the types of materials that can be processed are wide and the processing capacity is strong. The t-HPS method proposed by the present invention directly pressurizes the tubular material in the axial direction while constraining its radial deformation, so that the hydrostatic pressure inside the material can be as high as 15-GPa. This is currently unattainable by other processes including HPTT. Moreover, with the development of mold materials and design improvements, the hydrostatic pressure that can be provided will be higher. Plastic deformation under such high hydrostatic pressure conditions effectively inhibits the generation and development of surface and internal cracks, thus improving the machinability of many difficult-to-machine materials (such as magnesium alloys with poor plasticity, etc.). As we all know, materials such as magnesium alloys often have poor plasticity due to the hexagonal close-packed crystal structure and limited slip coefficients. When performing ARB or ECAP processing on hard-to-deform materials such as magnesium alloys, the samples often crack. In order to avoid cracking, it is often necessary to increase the processing temperature, which will inevitably increase the processing cost. More importantly, as the processing temperature increases, the grain refinement effect of the material will become worse, and the grains will become coarser. This has nothing to do with our improvement of material properties. Contrary to the original intention. In contrast, this method can realize plastic processing of many materials such as aluminum, copper, nickel, magnesium, titanium, tungsten and their alloys, and low-carbon steel at room temperature or at a lower heating temperature, thereby controlling and improving Its organizational structure improves its performance.

(3) The tubular finished product that can be obtained has a large size. The processing workpiece selected by the t-HPS method proposed by the present invention is in the shape of a tube, and its size is only limited by the scale of the equipment. Even in the laboratory, a tubular material with a height of ~100mm can be obtained by this method, which has good performance and can be applied in many fields with a little follow-up treatment. In addition, the obtained tubular material is cut along the axial direction and rolled. High-performance panels can be obtained by manufacturing.

Description of drawings

Figure 1 is a schematic diagram of the principle of cumulative composite rolling (ARB).

Figure 2 is a schematic diagram of the principle of the equal radial angular extrusion (ECAP) technology.

Fig. 3 is a schematic diagram of the principle of back pressure ECAP (BP-ECAP) technology.

Fig. 4 is a schematic diagram of the principle of high pressure torsion (HPT) technology.

Fig. 5 is a schematic diagram of the technical principle of high-pressure tube twisting (HPTT).

Fig. 6 is a schematic diagram of the technical principle of t-HPS of the present invention, wherein, 61-upper anvil, 62-rigid ring sleeve, 63-tubular workpiece, 64-lower anvil, 65-rigid mandrel; h is the height of tubular workpiece; r R is the inner radius of the tubular workpiece; R is the outer radius of the tubular workpiece; P is the pressure; T is the torque.

Figure 7 shows the strain distribution of the 2219T62 aluminum alloy tubular workpiece with finite element simulation size r=10mm and R=11mm after 90° circumferential shear deformation: the maximum strain along the radial direction is 10.79, the minimum strain is 8.41, and the statistical average value is 9.45 .

Fig. 8 is the device schematic diagram of t-HPS severe plastic deformation method embodiment, and wherein, (a) is exploded view: 1-support column, 2-up anvil head connection sleeve, 3-up anvil head connection bolt, 4-connection Sleeve square pin, 5-connecting sleeve cylindrical pin, 6-lower anvil, 7-tubular workpiece, 8-rigid collar, 9-lower ring washer, 10-upper ring washer, 11-integrated upper anvil With mandrel, 12-mandrel sleeve plate, 13-lower anvil connecting bolt, 14-servo motor, 15-hollow shaft reducer gearbox, 16-belt, 17-thrust bearing, 18-rigid ring sleeve, 19-sleeve connecting bolt; (b) main view.

Detailed ways

The material processing purpose of the present invention can be realized on the traditional extruder with constant pressure function: the tubular workpiece is placed on the lower anvil, the outer side of the workpiece is covered with a rotatable rigid ring, and the rigid mandrel passes through the center of the tubular workpiece. However, the upper anvil directly transmits the axial pressure to the workpiece, and the tubular workpiece tends to expand in the radial direction under the action of the huge axial pressure. The rigid disk and the mandrel play a role in restraining the radial deformation of the tubular workpiece. This design of applying high pressure to the end of the tubular workpiece while limiting its deformation results in the accumulation of high hydrostatic pressure (1GPa-15GPa) inside the workpiece. Under high hydrostatic pressure conditions, great friction will be generated on both the inner and outer walls of the tubular workpiece. Although the shape change of the tubular workpiece is limited, it has the freedom of axial rotation, and the upper and lower anvils are respectively installed on the upper and lower bottom plates of the extruder, so that the constraints (respectively mandrel and One of the rigid rings rotates around the central axis of the tubular workpiece while the other is fixed. Due to the friction between the inner and outer walls of the tubular workpiece and the equipment constraints, the material near the inner and outer walls of the workpiece rotates or is fixed with the constraints. immobile trend. Under the condition of high hydrostatic pressure, in order to maintain the continuity of the material, the materials of different thickness layers along the radial direction of the tubular workpiece will rotate at different angular velocities, that is, relative rotation will occur, and the material will realize circumferential shearing (circumferential shearing) driven by friction. ) deformation, it is very important that the deformation is the shear of the internal material of the workpiece, and does not change the macroscopic size and shape of the tubular workpiece.

The invention can make the tubular material undergo circumferential shear plastic deformation (up to 10-GPa) under the condition of high hydrostatic pressure (up to 15-GPa). In this way, through plastic deformation, the structure of the material can be controlled and optimized, and its performance can be improved.

At the same time, the present invention only needs to install a combination mold consisting of key elements such as an upper anvil, a mandrel, a lower anvil, and a rigid disk on the traditional extrusion equipment with constant pressure function, so that it can be processed at a lower temperature. (such as room temperature or lower heating temperature) to achieve a new severe plastic deformation (SPD) processing method - tubular workpiece high pressure shearing (t-HPS) technology. t-HPS has high technical feasibility, no special requirements for operation, and the required equipment is simple and easy to obtain. At the same time, because the present invention is a new plastic processing method realized by relying on traditional extrusion equipment, it expands the functions of traditional extrusion equipment. The invention is suitable for experimental research and industrial production of bulk ultrafine crystal and nano crystal materials prepared by severe plastic deformation. Utilizing the invention, high-performance metals, alloys, inorganic non-metallic materials and polymer materials can be prepared. The shape of the sample prepared by the t-HPS method is tubular, which has high potential and value for practical application.

The present invention will be described in further detail below in conjunction with the accompanying drawings.

Referring to Fig. 6, the method for high-pressure shear deformation of tubular materials in the present invention first selects the workpiece to be processed. The workpiece is tubular, and the inner wall and outer wall of the workpiece are respectively restrained by constraining bodies; then axial pressure is directly applied to the end of the workpiece to make the workpiece elastic. Deformation or micro-plastic deformation, accumulating hydrostatic pressure up to 1-15GPa in the workpiece; then providing torque to a constraint body in contact with the inner or outer wall of the workpiece to make it rotate around the central axis of the workpiece, while fixing the other constraint body, in Under the action of the circumferential friction between the restraining body and the inner and outer walls of the workpiece, the materials at different thicknesses in the radial direction inside the workpiece rotate at different angular velocities, thereby realizing the circumferential shear deformation of the workpiece.

The high-pressure shear deformation device for tubular materials of the present invention includes a press with constant pressure function and a mold with the functions of transmitting pressure, constraining deformation and realizing partial rotation; the mold includes: an upper anvil 61, a lower anvil 64, a fixed or A rotatable rigid mandrel 65 and a rotatable or fixed rigid ring 62; the upper anvil 61 and the lower anvil 64 are respectively installed on the upper ram and the base of the press, and the workpiece 63 is placed on the upper anvil 61 and the lower anvil. Between the anvil heads 64, the lower end of the upper anvil head 61 and the upper end of the lower anvil head 64 are in contact with the upper and lower end surfaces of the workpiece 63 through the provided bosses, and the cross-section of the bosses is a ring that completely matches the upper and lower end surfaces of the workpiece 63; The inside of the workpiece 63 is concentrically provided with a rigid mandrel 65 , the outer surface of the rigid mandrel 65 is in contact with the inner wall of the workpiece 63 , and the outer surface of the workpiece 63 is concentrically provided with a rigid collar, and the inner surface of the rigid collar 62 is in contact with the outer wall of the workpiece 63 . The inner surface of the rigid ring 62 and the outer surface of the rigid mandrel 65 are roughened to increase friction with the workpiece 63 . A clearance fit is adopted between the upper anvil 61 and the rigid ring sleeve 62 ; a clearance fit is adopted between the rigid mandrel 65 and the lower anvil 64 .

In the high-pressure shear deformation device for tubular materials of the present invention, one of the rigid mandrel 65 or the rigid ring 62 is rotatable, and the other is fixed, and the angle of rotation is unlimited.

In the high-pressure shear deformation device for tubular materials of the present invention, the rigid ring sleeve 62 can adopt a single-layer mold design, a prestressed winding mold design or a prestressed multi-layer mold design. The upper anvil 61 and the rigid mandrel 65 are two independent parts or adopt an integrated design to make it a part; the upper anvil 61 is an integral design or a combined design. Anvil head 64 ends have the annular boss that matches with the upper and lower end face shape of workpiece 63 respectively, when adopting combined design, anvil head comprises two parts of anvil head main body and ring gasket, and ring gasket cross section matches with tool 63 end face shapes.

The specific implementation details and equipment working conditions of the new method for severe plastic deformation proposed by the present invention will be described below in conjunction with FIG. 6 .

As shown in Figure 6, the t-HPS method consists of a mold consisting of four parts including 61-upper anvil, 62-rigid ring, 64-lower anvil and 65-rigid mandrel, combined with a pressure holding function machine, realized on a 63-tubular workpiece.

First, install 61-upper anvil and 64-lower anvil on the upper and lower bases (or workbenches) of the press respectively, and place 63-tubular workpiece between 61-upper anvil and 64-lower anvil Between, the lower end of 61-upper anvil head and the upper end of 64-lower anvil head are in contact with the upper and lower end surfaces of 63-tubular workpiece through the set boss, and the section of the boss is completely consistent with the upper and lower end faces of 63-tubular workpiece Ring; 63- the inner concentricity of tubular workpiece is provided with 65- rigid mandrel, the outer surface of 65- rigid mandrel is in contact with the inner wall of 63- tubular workpiece, the outer concentricity of 63- tubular workpiece is provided with 62- rigid ring sleeve, 62- The inner surface of the rigid collar is in contact with the outer wall of the 63-tubular workpiece.

At this time, 63-tubular workpiece is in the airtight cavity formed by 61-upper anvil, 62-rigid collar, 64-lower anvil and 65-rigid mandrel. Then, the press presses down on the 61-upper anvil, and keeps the pressure constant at a certain value. During the downward displacement of the 61-upper anvil, the 61-upper anvil will also produce downward pressure on the 3-tubular workpiece, because the 63-tubular workpiece is subjected to the 61-upper anvil, 62-rigid ring sleeve, 64 -Constraint of the closed cavity formed by the lower anvil and the 65-rigid mandrel, thus generating high hydrostatic pressure (up to ~15GPa) inside. Apply a hoop thrust to the 62-rigid ring sleeve, and make it hoop-rotate under the action of torque. At the same time, 61-upper anvil, 64-lower anvil and 65-rigid mandrel do not rotate. At 62- Under the action of friction between the rigid ring and the 63-tubular workpiece and the 65-mandrel and the 63-tubular workpiece, the 63-tubular workpiece will undergo circumferential shear deformation. As the rotation angle increases, the amount of shear deformation becomes large, which effectively controls and optimizes the structure of the material and improves its performance.

In addition, under the condition that other conditions remain unchanged, the circular rotation 65-rigid mandrel and fixed 62-rigid collar can produce a similar circumferential shear plastic deformation effect on the tubular material. The schematic diagram of the t-HPS technology principle in this case is omitted.

In order to investigate the mechanical behavior of the tubular workpiece during the t-HPS process, especially the strain distribution, two-dimensional and three-dimensional finite element simulations were carried out on the method. In the finite element simulation, the 2219T62 aluminum alloy workpiece was selected. The material performance parameters of the aluminum alloy are shown in Table 1. The rheological law of the material can be calculated using the Crussard-Jaoul strain hardening model be described. where is flow stress, σ ₀ =290MPa is yield strength, K=248MPa is strength coefficient, ε _p is plastic strain, n=0.36 is strain hardening exponent.

For simplicity, the simulation temperature is room temperature, and the temperature rise and strain rate sensitivity of the material during deformation are not considered. The results show that the t-HPS method can accumulate very high strain in larger workpieces. As shown in Figure 7, the tubular workpiece with an inner diameter of 20mm and an outer diameter of 22mm only undergoes a 90-degree circumferential shear, and its average strain is Can reach 9.45.

Table 1. Mechanical constants and physical properties of 2219T62 aluminum alloy material selected by t-HPS process finite element simulation

The present invention will be described in further detail below in conjunction with the examples.

As shown in Figure 8, the device consists of three parts: the realization part of the t-HPS severe plastic deformation method principle, the power device and the connection part. Figure 8(a) is an exploded view of the device, detailing the composition of the device.

6-lower anvil head, 7-tubular workpiece, 8-rigid ring sleeve, 9-lower ring washer, 10-upper ring washer, 11-integrated upper anvil head and mandrel and 12-mandrel sleeve plate constitute the whole The principle realization part of the device. 7-The tubular workpiece passes through the 11-integrated upper anvil and the mandrel, and an annular gasket (9-, 10-) is placed on the upper and lower end faces, the workpiece is surrounded by 8-rigid rings, and the upper and lower anvils (11 -, 6-) When the 7-tubular workpiece is axially pressed through the upper and lower gaskets (9-, 10-), the 11-mandrel and the 8-rigid ring restrict its radial expansion, and the accumulation inside the workpiece High hydrostatic pressure. The end of the 11-mandrel is a hexagonal prism, which has the same shape and size as the hole in the 12-mandrel sleeve plate. After the mandrel is inserted into the hole in the cover plate, its rotation will be constrained. Apply a hoop thrust to the 8-rigid ring sleeve, and make it rotate under the action of torque at a rotation speed of 1-5rpm. -Under the action of friction between the rigid collar and the 7-tubular workpiece and the 11-mandrel and the 7-tubular workpiece, the 7-tubular workpiece will undergo circumferential shear deformation.

In this embodiment, the upper anvil and the mandrel adopt an integrated design, which on the one hand makes the mandrel easy to fix and on the other hand facilitates the demoulding of the tubular workpiece. In addition, the upper and lower anvils (11-, 6-) do not directly contact the 7-tubular workpiece, and the pressure is transmitted to the workpiece through the upper and lower annular gaskets (9-, 10-). This design is because the stress on the part directly in contact with the workpiece section is very bad. Adding an annular gasket made of hard alloy can improve the service life of the anvil and reduce the cost of mold replacement. Considering that the 8-rigid ring sleeve and the 11-mandrel need to move freely in the axial direction and freely rotate in the circumferential direction, while the relationship between the 6-lower anvil and the 11-mandrel only requires free movement in the axial direction. Therefore, when selecting the fit between the hole and the shaft, 11-integrated upper anvil head, mandrel and 8-rigid ring sleeve adopt F7/h6 base shaft clearance fit; 11-integrated upper anvil The head, mandrel and 6-lower anvil adopt H7/g6 base hole clearance fit. This choice of clearance fit is also advantageous from the standpoint of demoulding.

The rigid ring rotates and shears the tubular workpiece in a circumferential direction under the action of friction, and the torque required for this action is realized by the power device. The power unit drives the 15-hollow shaft reducer to output torque through a 14-servo motor through a 16-belt pulley.

The connecting part composed of 2-upper anvil head connection sleeve, 3-upper anvil head connection bolt, 4-connection sleeve square pin and 5-connection sleeve cylindrical pin connects 11-integrated upper anvil head and mandrel with The upper platen of the press is connected. The connecting part consisting of 1-support column, 13-lower anvil connecting bolt, 17-thrust bearing, 18-rigid ring sleeve and 19-sleeve connecting bolt will

6-The lower anvil head is connected to the lower base plate of the press through 1-support column, while 18-rigid ring sleeve and 19-sleeve connecting bolt are connected to 15-hollow shaft reducer and 8-rigid ring sleeve to realize torque transfer. The 17-thrust bearing reduces the resistance of axial friction to the rotation of the 8-rigid collar.

18- When the rigid ring is designed with a prestressed winding mold, the inner layer should be made of a material with high hardness and toughness, such as die steel; the winding layer should be made of a material with high toughness, such as spring steel wire or spring steel belt; the outer layer should be made of toughness Higher materials, such as medium carbon steel. 18-When the rigid ring is designed with prestressed multi-layer rings, the inner layer should be made of a material with high hardness and toughness, such as die steel; the other layers should be made of a material with high toughness, such as medium carbon alloy steel or die steel. 11- The integrated upper anvil head and mandrel, and the lower anvil head are inlaid with hard alloy in the working part, and the material of the rest parts is mold steel. 9-the lower ring washer, 10-the upper ring washer are selected hard alloy or steel-bonded hard alloy.

The specific materials are as follows: die steel is Cr5Mo1V steel; spring steel is 65Mn steel; medium carbon steel is No. 45 steel; medium carbon alloy steel is 45Mn steel; hard alloy is YG6A.

A front view of the assembled t-HPS device in this embodiment is shown in Figure 8(b).

Through this scheme, a preliminary experimental study was carried out on industrial pure aluminum, 6063 aluminum alloy and AZ31 magnesium alloy tubular workpieces. The inner diameter of the tubular workpiece is 40 mm, the outer diameter is 46 mm, and the height is 40 mm. Before and after deformation, the macroscopic size and shape of the workpiece remain unchanged.

The average grain size of industrial pure aluminum before t-HPS is 24μm, and the yield strength of compression test is 73.7MPa; under 1.5GPa hydrostatic pressure and 1rpm rotation speed, after 30° t-HPS deformation, the average strain reaches 4, the average The grain size reaches 633nm, and the compression test yield strength increases to 261.3MPa.

The average grain size of 6063 aluminum alloy before t-HPS is 80 μm, and the yield strength of compression test is 156.8 MPa; under the hydrostatic pressure of 2.5 GPa and the rotation speed of 1 rpm, after t-HPS deformation of 60°, the average strain reaches 8, and the average grain size The particle size reaches 561nm, and the yield strength of compression test increases to 447.6MPa.

AZ31 magnesium alloy has poor plasticity, and we heated the mold at 100°C. The average grain size before t-HPS was 27 μm, and the yield strength of the compression test was 276.4 MPa; under the hydrostatic pressure of 3 GPa and the rotation speed of 1 rpm, after 90° t-HPS deformation, the average strain reached 9, and the average grain size reached 335nm, the compression test yield strength increased to 590.2MPa.

Claims (6)

1. A tubular material high-pressure shear deformation device is characterized in that: it comprises a press with constant pressure function and a mold with transmission pressure, constraint deformation and partial rotation functions; said mold includes: anvil (61) , the lower anvil (64), the fixed or rotatable rigid mandrel (65) and the rotatable or fixed rigid ring (62); the upper anvil (61) and the lower anvil (64) are respectively installed in the press On the upper indenter and the base, the workpiece (63) is placed between the upper anvil (61) and the lower anvil (64), and the lower end of the upper anvil (61) and the upper end of the lower anvil (64) pass through the set boss In contact with the upper and lower end surfaces of the workpiece (63), the cross section of the boss is a ring that completely matches the upper and lower end surfaces of the workpiece (63); the inner part of the workpiece (63) is concentrically provided with a rigid mandrel (65), and the rigid core The outer surface of the shaft (65) contacts with the inner wall of the workpiece (63), and the outer concentricity of the workpiece (63) is provided with a rigid collar (62), and the inner surface of the rigid collar (62) contacts with the outer wall of the workpiece (63). 2. The high-pressure shear deformation device for tubular materials according to claim 1, characterized in that: the inner surface of the rigid ring (62) and the outer surface of the rigid mandrel (65) are roughened to increase the contact with the workpiece (63) friction between. 3. The high-pressure shear deformation device for tubular materials according to claim 1, characterized in that: clearance fit is used between the upper anvil (61) and the rigid ring (62); the rigid mandrel (65) and the lower anvil (64) adopt clearance fit between. 4. The high-pressure shear deformation device for tubular materials according to claim 1, characterized in that: one of the rigid mandrel (65) or the rigid collar (62) is rotatable, while the other is fixed and rotates angle is unlimited. 5. The high-pressure shear deformation device for tubular materials according to claim 1, characterized in that: the rigid ring (62) can be designed with a single-layer mold, a prestressed winding mold or a prestressed multi-layer mold. 6. The high-pressure shear deformation device for tubular materials according to claim 1, characterized in that: the upper anvil (61) and the rigid mandrel (65) are two independent parts or are integrated into one part ; The upper anvil (61) is an integral design or a combined design. When the overall design is adopted, the ends of the upper anvil (61) and the lower anvil (64) are respectively matched with the upper and lower end surfaces of the workpiece (63) The annular boss, when adopting combined design, anvil head comprises two parts of anvil head main body and ring washer, and ring washer cross-section matches with workpiece (63) end face shape.