WO2012100673A1

WO2012100673A1 - High pressure shear deformation method for tubular material and device thereof

Info

Publication number: WO2012100673A1
Application number: PCT/CN2012/070156
Authority: WO
Inventors: 王经涛; 李政; 王进; 刘金强; 尹德良; 刘冉
Original assignee: 南京理工大学
Priority date: 2011-01-28
Filing date: 2012-01-10
Publication date: 2012-08-02
Also published as: CN102189706A; CN102189706B

Abstract

Disclosed are a high pressure shear deformation method for tubular material and a device thereof. Firstly, a workpiece (63, 7) to be machined is selected, with the workpiece (63, 7) being of a tubular shape and with the inner wall and the outer wall of the workpiece (63, 7) being respectively restrained by restraining bodies; then axial pressure is applied directly to the ends of the workpiece (63, 7) so that the workpiece (63, 7) experiences elastic deformation or slight plastic deformation, with hydrostatic pressure of up to 1 to 15 GPa accumulated within the workpiece (63, 7); after that, a torque is provided to one restraining body in contact with the inner wall or the outer wall of the workpiece (63, 7) so as to make it rotate about the central axis of the workpiece (63, 7) while the other restraining body is fixed; under the action of an annular friction force between the restraining body and the inner wall of the workpiece (63, 7), the interior materials of the workpiece (63, 7), at different thicknesses along the radial direction are rotated at different angular velocities so as to achieve an annular shear deformation of the workpiece (63, 7). The high pressure shear deformation method for tubular material and the device thereof is of high technological feasibility without special requirements for operation, and the required equipment is simple and easy to obtain.

Description

High-pressure shear deformation method of tubular material and device thereof

The invention relates to the field of material processing engineering, in particular to a method and a device for realizing circumferential shear plastic deformation of a tubular material, which are mainly applied to various metal and alloy materials, inorganic non-metal materials and polymer materials, etc., to realize these The material is plastically deformed at high hydrostatic pressure, thereby controlling and optimizing its structural structure and improving 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 SPD method refines the grain effect clearly, and can refine the internal structure of the material to sub-micron, nano-scale or even amorphous [RZ Valiev. Nature materials. 2004 (3): 511-516.; RZ Valiev, AK Mukheq' Ee. Scripta mater. 2001 (44): 1747-1750.]. In recent years, the technology of preparing bulk nanostructure materials by SPD method has received widespread attention from experts and scholars in the field of materials science. At the same time, a large number of studies have pushed the development of SPD technology in the preparation of bulk ultrafine crystals and nanocrystalline materials. The research team led by RZ Valiev of Ufa Aviation Technology University in Russia believes that the preparation of ultrafine grained materials by SPD method should satisfy a number of conditions [RZ Valiev, RK Islamgaliev, I V. Alexandrov. Progress in Materials Science. 2000 (45): 103 -189.], mainly includes: 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 popular SPD methods are mainly accumulative roll-bonding (ARB) technology, equal-channel angular pressing (ECAP) technology, and high-pressure torsion (referred to as high-pressure torsion). HPT) technology, etc. The ARB technology is shown in Figure 1. It can continuously prepare thin-plate ultrafine-grained structural materials, and is easy to implement on traditional rolling mills. The equipment is simple and practical. However, in the ARB process, 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, the hydrostatic pressure that can be achieved due to the deformation of the material during the rolling process is not high enough, and the cracking problem occurs after a certain amount of deformation is accumulated in the process [N. Tsuji, Y. Saito, SH Lee, et Al. Advanced Engineering Materials. 2003 (5): 338-344.]. The ECAP technology is shown in Figure 2. The use of this technology for ultra-fine grain metal processing has great potential. However, for some difficult-to-machine alloys (such as magnesium alloys), ECAP often cracks. If the deformation temperature is increased, it will affect the life of the mold, and on the other hand, it will affect the grain refining effect. In addition, due to the limitation of the mold material, the deformation temperature cannot be increased without limitation. Moreover, in order to achieve large cumulative plastic deformation, ECAP requires multiple passes and is complicated to operate. Back pressure ECAP (back pressure Equal-channel angular pressing (BP-ECAP) is the ECAP technology that applies back pressure to the die exit channel. As shown in Figure 3, the cracking problem of the difficult-to-deform metal ECAP can be solved to some extent, thereby improving the microstructure and material. Mechanical properties; The applied back pressure is limited, and the hydrostatic pressure is generally maintained at several hundred megapascals [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 mold strength. The HPT technology shown in Figure 3 is the most suitable condition for the preparation of ultrafine grained materials in accordance with the SPD method mentioned in the previous section. Among the existing SPD technologies, HPT technology has the strongest grain refinement capability. However, the thickness of the specimen that HPT can process is small [AP Zhilyaev, TG Langdon. Progress in Materials Science. 2008 (53): 893-979.], the processed disc specimens are radially present. Large strain gradient, uneven deformation, and uneven grain refinement.

T0th et al. [LS Toth, M. Arzaghi, JJ Fundenberger, B. Beausir: Scr. Mater. Vol. 60 (2009), p. 175] proposed a high-pressure tube twisting (HPTT) method for tubular materials. As shown in Fig. 5, an elastic mandrel is placed inside the tubular sample, and a rigid disk is placed on the outer side, and both ends of the sample are fixed by a baffle. 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 creates a radial pressure in the opposite direction to the outer wall of the tubular sample, thereby creating hydrostatic pressure in the tubular sample. At this time, the ring sleeve is rotated, and the tubular sample is subjected to the circumferential shear deformation under the action of the surface ring friction. This method is very good. The main problem is that the method of loading the sample is radial loading. That is to say, the method directly applies axial pressure to the mandrel, and the mandrel produces a diameter on the sample. To the pressure. In this loading mode, the pressure is not directly loaded in the axial direction of the tubular material, and the hydrostatic pressure of the sample is derived from the elastic deformation of the mandrel after being pressed. Since the elastic deformation of the material is unlikely to be large, it is difficult to produce high Hydrostatic pressure, therefore, provides limited hoop friction and is only suitable for pure metals with lower strength. For materials with higher strength, the frictional force that can be generated does not reach the yield strength of the material, and it is prone to slippage and the like, and the required deformation cannot be achieved.

Another problem with this method is that the baffle at the ends of the tubular sample is a cantilever beam structure, which has insufficient constraint on the axial deformation of the sample. When the hydrostatic pressure of the sample is high, the material is easily extruded from the gap. , affecting the processing process. Summary of the invention

It is an object of the present invention to provide a new severe plastic deformation method and apparatus therefor: Tube-High Pressure Shearing (t-HPS) technology. The technique satisfies a number of conditions for the preparation of ultrafine grained materials by the 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 that requires multiple operations such as AB, ECAP, and back pressure ECAP. At the same time, due to the nature of the loading method, the method also overcomes the hydrostatic pressure of T0th et al. Problems such as insufficient force can provide high hydrostatic pressure conditions similar to HPT technology when processing materials, which is suitable for processing difficult metals and alloys, achieving the effect of controlling and optimizing the structure of materials and improving their performance.

The technical solution for achieving the object of the present invention is: a high-pressure shear deformation method for a tubular material, first selecting a machined workpiece, the workpiece is tubular, and constraining the inner and outer walls of the workpiece respectively; then directly applying an axial direction to the end of the workpiece The pressure causes the workpiece to undergo elastic deformation or slight plastic deformation, accumulating high hydrostatic pressure in the workpiece; then providing a torque to a constraining body in contact with the inner or outer wall of the workpiece to rotate around the central axis of the workpiece while fixing another binding body Under the action of the frictional force between the restraining body and the inner and outer walls of the workpiece, the materials at different thicknesses in the radial direction of the workpiece rotate at different angular velocities, thereby achieving the circumferential shear deformation of the workpiece.

A high-pressure shear deformation device for a tubular material, comprising a press having a constant pressure function and a mold having a transfer pressure, a constraining deformation, and a partial rotation function; the mold comprising: an upper anvil, a lower anvil, fixed or rotatable a rigid mandrel and a rigid or fixed rigid collar; the upper anvil and the lower anvil are respectively mounted on the upper pressing head and the base of the press, and the workpiece is placed between the upper anvil and the lower anvil, the upper anvil The upper end and the upper end of the lower anvil are in contact with the upper and lower end faces of the workpiece through a boss provided, and the cross section of the boss is a ring which completely conforms to the upper and lower end faces of the workpiece; the inner part of the workpiece is concentrically provided with a rigid mandrel, a rigid mandrel The outer surface is in contact with the inner wall of the workpiece, and the outer portion of the workpiece is concentrically provided with a rigid collar, and the inner surface of the rigid collar 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 present invention is a severe plastic deformation method which can be realized in a single pass on a conventional extruder having a constant pressure function. In contrast, methods such as cumulative rolling (ARB), multi-directional forging, equal-cavity extrusion (ECAP), and back-pressure ECAP often require many repetitive process passes to achieve high strain plastic deformation, and high labor consumption. . The method utilizes a rigid collar, a tubular workpiece, and a friction between the mandrel and the tubular workpiece, rotates the rigid collar and fixes the mandrel such that the outer region of the tubular workpiece in contact with the rigid collar is in contact with the inner core The zone region is circumferentially sheared to achieve severe plastic deformation under a single process pass. The true strain is 1 to 10, or even higher. As described in the foregoing technical scheme, the t-HPS method proposed by the present invention has a simple principle and is easy to obtain, and can be realized in a general plastic forming laboratory.

(2) The hydrostatic pressure that can be supplied is high, so the wide range of materials that can be processed and the processing ability are strong. The t-HPS method proposed by the present invention directly pressurizes the tubular material axially while restraining its radial deformation, so that a hydrostatic pressure of up to 15~GPa can be generated inside the material. This is currently not possible with other processes including HPTT. Moreover, with the development of mold materials and the improvement of design, the hydrostatic pressure that can be provided will be higher. Plastic deformation under such high hydrostatic pressure conditions effectively suppresses the generation and development of the surface and internal cracks of the material, thereby improving the workability of many difficult-to-machine materials (such as magnesium alloys with poor plasticity). It is well known that materials such as magnesium alloys are arranged in a hexagonal shape due to the crystal structure. The slip coefficient is limited and often has poor plasticity. When ARB or ECAP is processed on difficult-to-deform materials such as magnesium alloy, the sample often cracks. 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 refining effect of the material becomes worse and the grains become coarser, which improves the material properties. The original intention is opposite. In contrast, the method can achieve 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 enhances its performance.

(3) The tubular product that can be obtained is large in size. The workpiece processed by the t-HPS method proposed by the present invention is tubular, and its size is limited only by the scale of the equipment. Even in the laboratory, the tubular material of ~100mm height can be obtained by this method, which has good performance and can be applied in many fields after a little subsequent treatment. In addition, the obtained tubular material is axially cut and rolled. High performance sheeting is obtained. DRAWINGS

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

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

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

Figure 4 is a schematic diagram of the principle of high voltage torsion (HPT) technology.

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

Figure 6 is a schematic diagram of the t-HPS technology of the present invention, wherein: 61-upper anvil, 62-rigid collar, 63-tubular workpiece, 64-lower anvil, 65-rigid mandrel; h is the height of the tubular workpiece; The inner radius of the tubular workpiece; the outer radius of the R tubular workpiece; P is the pressure; T is the torque.

Fig. 7 is the strain distribution of a 2219T62 aluminum alloy tubular workpiece with a finite element simulation size of r=10mm and R=llmm after 90° hoop shear deformation: maximum radial strain 10.79, minimum strain 8.41, statistical average 9.45 .

Figure 8 is a schematic view of the apparatus for the t-HPS severe plastic deformation method embodiment, wherein (a) is an exploded view: 1- support column, 2-upper anvil connection sleeve, 3-upper anvil connection bolt, 4-connection Sleeve square pin, 5-connected sleeve cylindrical pin, 6-lower anvil, 7-tubular workpiece, 8-rigid ring sleeve, 9-lower annular washer, 10-upper annular washer, 11-integrated upper anvil With mandrel, 12-core bushing 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 object of the present invention can be realized on a conventional extruder having a constant pressure function: a tubular workpiece is placed on the lower anvil, and a rectangular outer sleeve is provided with a rotatable rigid ring sleeve, and the rigid mandrel is worn from the center of the tubular workpiece. Over, on The anvil directly transmits axial pressure to the workpiece, and the tubular workpiece has a tendency to expand radially under the action of a large axial pressure. The rigid disc and the mandrel constrain the radial deformation of the tubular workpiece. The design of the end of the workpiece while applying high pressure while limiting its deformation causes a high hydrostatic pressure (lGPa~15 GPa) to be accumulated inside the workpiece. Under high hydrostatic pressure conditions, a large amount of friction will be generated on the inner and outer walls of the tubular workpiece. Although the shape change of the tubular workpiece is limited, it has the degree of freedom of rotation in the axial direction, and the upper and lower anvils are respectively mounted on the upper and lower bottom plates of the extruder, so that the binding bodies (the mandrel and the respectively respectively are in contact with the inner wall or the outer wall of the workpiece) One of the rigid ring sleeves rotates around the central axis of the tubular workpiece and the other one is fixed. Due to the friction between the inner and outer walls of the tubular workpiece and the device binding body, the material near the inner and outer walls of the workpiece rotates or fixes with the binding body. The trend of not moving. Under high hydrostatic pressure conditions, in order to maintain the continuity of the material, the material of the tubular workpiece in different thickness layers in the radial direction will rotate at different angular velocities, that is, relative rotation occurs, and the material is driven by friction to achieve circumferential shearing. ) Deformation, it is important that the deformation is the shear of the material inside the workpiece and does not change the macroscopic shape of the tubular workpiece.

The invention enables the tubular material to undergo a circumferential shear plastic deformation under the condition of high hydrostatic pressure (up to 15~GPa) (it should be up to 10~). Thereby controlling and optimizing the structure of the material and improving its performance through plastic deformation.

At the same time, the present invention only needs to install a combined mold composed of key elements such as an upper anvil, a mandrel, a lower anvil and a rigid disc on a conventional extrusion device having a constant pressure function, which can be 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 shear (t-HPS) technology. The t-HPS technology is highly feasible, with no special requirements for operation, and the required equipment is simple and easy to obtain. At the same time, since the present invention is a new plastic working method realized by a conventional extrusion apparatus, the function of the conventional extrusion apparatus is expanded. The invention is suitable for experimental research and industrial production of bulk ultrafine crystal and nanocrystalline materials for severe plastic deformation. With the present invention, high-performance metals, alloys, inorganic non-metallic materials, and polymer materials can be prepared. The sample prepared by the t-HPS method has a tubular shape and has high practical application potential and value.

The invention is further described in detail below with reference to the accompanying drawings.

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

The tubular material high-pressure shear deformation device of the present invention comprises a press having a constant pressure function and a mold having a transfer pressure, a constraining deformation and a partial rotation function; the mold comprises: an upper anvil 61, a lower anvil 64, a fixed or a rotatable rigid mandrel 65 and a rotatable or fixed rigid collar 62; an upper anvil 61 and a lower anvil 64 are respectively mounted on the upper pressing head and the base of the press, and the workpiece 63 is placed on the upper anvil 61 and Between the lower anvils 64, the lower end of the upper anvil 61 and the upper end of the lower anvil 64 are in contact with the upper and lower end faces of the workpiece 63 through the boss provided, and the cross section of the boss is a ring which completely conforms to the upper and lower end faces of the workpiece 63. The inner portion 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. The outer portion 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 collar 62 and the outer surface of the rigid mandrel 65 are textured to increase friction with the workpiece 63. A clearance fit is used between the upper anvil 61 and the rigid collar 62; a clearance fit is used between the rigid mandrel 65 and the lower anvil 64.

In the tubular material high-pressure shear deformation device of the present invention, one of the rigid mandrel 65 or the rigid cuff 62 is rotatable, and the other is fixed, and the angle of rotation is not limited.

The tubular material high-pressure shear deformation device of the present invention may adopt a single-layer mold design, a pre-stressed winding mold design or a pre-stressed multilayer mold design. The upper anvil 61 and the rigid mandrel 65 are two independent parts or are integrated into a part; the upper anvil 61 is designed as a whole or in combination, and when the overall design is used, the upper anvil 61 and the lower part The ends of the anvil 64 have annular bosses respectively conforming to the shape of the upper and lower end faces of the workpiece 63. When the combination is designed, the anvil comprises two parts, an anvil main body and an annular washer, and the annular gasket cross-section conforms to the shape of the end face of the work 63.

The specific implementation details and equipment operation of the new method of severe plastic deformation proposed in accordance with the present invention will be described below with reference to FIG.

As shown in Fig. 6, the t-HPS method consists of a mold consisting of a 61-upper anvil, a 62-rigid annulus, a 64-lower anvil and a 65-rigid mandrel, combined with a pressure-holding pressure. Machine, implemented on a 63-tubular workpiece.

First, the 61-upper anvil and the 64-lower anvil are respectively mounted on the upper and lower bottom plates (or the workbench) of the press, and the 63-tubular workpiece is placed on the 61-upper anvil and the 64-lower anvil. The upper end of the 61-upper anvil and the upper end of the 64-lower anvil are in contact with the upper and lower end faces of the 63-tubular workpiece through a boss provided, and the cross section of the boss is completely coincident with the upper and lower end faces of the 63-tubular workpiece. Ring-shaped; 63- tubular workpiece is internally concentrically provided with a 65-rigid mandrel, 65-rigid mandrel outer surface is in contact with the inner wall of the 63-tubular workpiece, and 63-tubular workpiece is concentrically provided with a 62-rigid collar, 62- The inner surface of the rigid collar is in contact with the outer wall of the 63-tubular workpiece.

At this time, the 63-tubular workpiece is in a closed cavity composed of a 61-upper anvil, a 62-rigid annulus, a 64-lower anvil, and a 65-rigid mandrel. Then, the press presses the 61-upper anvil and maintains the pressure constant at a certain value. 61- During the downward displacement of the upper anvil, the 61-upper anvil will also exert downward pressure on the 3-tubular workpiece, since the 63-tubular workpiece is subjected to a 61-upper anvil, a 62-rigid collar, 64 - a closed cavity formed by a lower anvil and a 65-rigid mandrel The bundle, therefore, produces a high hydrostatic pressure inside it (can be as high as ~15GPa). The circumferential thrust is applied to the 62-rigid collar, which is rotated in the direction of the torque. At the same time, the 61-upper anvil, the 64-lower anvil and the 65-rigid mandrel do not rotate, at 62- Under the action of the friction between the rigid ring sleeve and the 63-tubular workpiece and the 65-core shaft and the 63-tube workpiece, the 63-tubular workpiece will undergo circumferential shear deformation. As the angle of rotation increases, the amount of shear deformation becomes large, thereby effectively controlling and optimizing the structure of the material and improving its performance.

In addition, the other conditions are the same, the circumferential rotation of the 65-rigid mandrel and the fixing of the 62-rigid ring can produce a similar hoop shear plastic deformation effect on the tubular material. The schematic diagram of the t-HPS technology in this case is omitted.

In order to investigate the mechanical behavior of the tubular workpiece during the t-HPS process, especially the distribution of strain, the two-dimensional and three-dimensional finite element simulation analysis of the method was carried out. In the finite element simulation, the 2219T62 aluminum alloy workpiece was selected. The material properties of the aluminum alloy are shown in Table 1. The rheological law of the material can be described by the Crussard-Jaoul strain hardening model II + ^^. Among them, the rheological stress, = 290 _Mpa is the yield strength, _{K = 248 MPa} is the strength coefficient, ^ is the plastic strain, and n = 0.36 is the strain hardening index.

For simplicity, the simulated temperature is room temperature and does not take into account the temperature rise and strain rate sensitivity of the material during deformation. The results show that the t-HPS method can accumulate very high strains in large-sized workpieces. As shown in Fig. 7, a tubular workpiece with an inner diameter of 20 mm and an outer diameter of 22 mm undergoes only a 90-degree circumferential shear, and the highest strain is up to 10.78, the minimum strain is 8.41, and the average strain statistics can reach 9.45.

The present invention will be further described in detail below with reference to the embodiments.

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

6-lower anvil, 7-tubular workpiece, 8-rigid ring sleeve, 9-lower annular washer, 10-upper annular washer, 11-integrated upper anvil and mandrel and 12-core bushing plate Principle implementation of the device. 7-Tubular workpiece passes through the 11-integrated upper anvil and mandrel, with an annular gasket (9-, 10-) placed on the upper and lower end faces, and the workpiece is surrounded by an 8-rigid ring, upper and lower anvils (11 -, 6-) When the 7-tubular workpiece is axially pressed by the upper and lower washers (9-, 10-), the 11-mandrel and the 8-rigid collar constrain its radial expansion and accumulate inside the workpiece. High hydrostatic pressure. The end of the 11-mandrel is a hexagonal prism. Same as the shape of the hole in the 12-core bushing. After the mandrel is inserted into the hole in the sleeve, its rotation will be constrained. Applying a circumferential thrust to the 8-rigid collar, rotating it under the action of torque, the rotation speed is l~5rpm, at the same time, the 11-integrated upper anvil and mandrel are constrained without rotation, at 8 - Under the action of the friction between the rigid collar and the 7-tubular workpiece and the 11-mandrel and the 7-tube workpiece, the 7-tubular workpiece will undergo circumferential shear deformation.

In this embodiment, the upper anvil and the mandrel are integrally designed to facilitate the fixing of the mandrel on the one hand and the demolding of the tubular workpiece on the other hand. 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 part that is in direct contact with the workpiece section is subjected to severe stress. The addition of an annular gasket made of cemented carbide can increase the service life of the anvil and reduce the cost of mold replacement. Considering that the 8-rigid ring sleeve and the 11-core shaft need to move both in the axial direction and in the circumferential direction, the 6-lower anvil and the 11-core shaft only need to be axially owned. Move, so when selecting the fit between the hole and the shaft, the 11-integrated upper anvil, the mandrel and the 8-rigid ring are made of F7/h6 base shaft clearance fit; 11- integrated upper anvil The head, mandrel and 6-lower anvil are made of H7/g6 base hole clearance fit. This choice of clearance fit is also advantageous from the standpoint of demolding.

The rigid ring rotates and causes the tubular workpiece to be circumferentially sheared under the action of friction. The torque required for this action is achieved by the power device. The power unit drives the 15-hollow shaft reducer output torque through a 16-belt through a 14-servo motor.

The 11-integrated upper anvil and mandrel are connected by a 2-upper anvil connection sleeve, a 3-upper anvil connection bolt, a 4-connection sleeve square pin, and a 5-connection sleeve cylindrical pin. The upper platen of the press is connected. The connection made up of 1-support column, 13- lower anvil connection bolt, 17-thrust bearing, 18-rigid collar sleeve and 19-sleeve connection bolt will

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

When the 18-rigid ring sleeve is designed with prestressed winding mold, the inner layer selects materials with higher hardness and toughness, such as die steel; the wound layer is made of high toughness material, such as spring steel wire or spring steel strip; Higher material, such as medium carbon steel. When the 18-rigid ring sleeve is designed with prestressed multi-layer ring sleeve, the inner layer selects materials with higher hardness and toughness, such as die steel; the other layer selects materials with higher toughness, such as medium carbon alloy steel or die steel. 11-Integral The upper anvil and the mandrel and the lower anvil are inlaid with hard alloy at the working part, and the other parts are made of die steel. The 9-lower ring washer and the 10-upper ring washer are made of hard alloy or steel-bonded carbide.

The specific materials are as follows: The mold steel is Cr5MolV steel; the spring steel is 65Mn steel; the medium carbon steel is 45 steel; the medium carbon alloy steel is 45Mn steel; the hard alloy is YG6A. In this embodiment, the front view of the assembled t-HPS device is shown in Figure 8(b).

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

The average grain size of industrial pure aluminum before t-HPS is 24μηι, and the yield strength of compression test is 73.7MPa. Under the hydrostatic pressure of 1.5GPa, the t-HPS deformation is 30° at a rotation speed of 1rpm, and the average strain reaches 4, The average grain size reached 633 nm and the compression test yield strength increased to 261.3 MPa.

The average grain size of 6063 aluminum alloy before t-HPS is 80μηι, compression test yield strength is 156.8MPa; at 2.5GPa hydrostatic pressure, the t-HPS deformation at 60° is rotated at 60°, the average strain reaches 8, average The grain size reached 561 nm, and the compression test yield strength increased to 447.6 MPa.

The AZ31 magnesium alloy is inferior in plasticity, and we heat the mold at 100 °C. The average grain size before t-HPS was 27 μηι, the compression yield strength was 276.4 MPa; the t-HPS deformation at 90° at a rotational speed of 1 MPa under a hydrostatic pressure of 1 GP, the average strain reached 9, the average grain size At 335 nm, the compression test yield strength increased to 590.2 MPa.

Claims

Claim

A method for high-pressure shear deformation of a tubular material, characterized in that: firstly, the workpiece is machined, the workpiece is tubular, and the inner wall and the outer wall of the workpiece are respectively restrained by the binding body; then the axial pressure is directly applied to the end of the workpiece, so that the workpiece Elastic deformation or slight plastic deformation occurs, accumulating high hydrostatic pressure in the workpiece; then providing a torque to a constraining body that is in contact with the inner or outer wall of the workpiece, rotating it around the central axis of the workpiece while fixing another binding body, in the binding body Under the action of the circumferential frictional force between the inner and outer walls of the workpiece, the materials at different thicknesses in the radial direction of the workpiece are rotated at different angular velocities, thereby achieving the circumferential shear deformation of the workpiece.

2. The high-pressure shear deformation method of tubular material according to claim 1, wherein: the accumulated hydrostatic pressure in the workpiece is as high as l~15 GPa.

3. A tubular material high-pressure shear deformation device, comprising: a press having a constant pressure function and a mold having a transfer pressure, a constraining deformation, and a partial rotation function; the mold comprising: an upper anvil [61] , the lower anvil [64], the fixed or rotatable rigid mandrel [65] and the rotatable or fixed rigid collar [62]; the upper anvil [61] and the lower anvil [64] are respectively mounted on the press On the upper head and the base, the workpiece [63] is placed between the upper anvil [61] and the lower anvil [64], and the upper end of the upper anvil [61] and the upper end of the lower anvil [64] are passed through the provided bosses. In contact with the upper and lower end faces of the workpiece [63], the cross section of the boss is a ring that perfectly matches the upper and lower end faces of the workpiece [63]; the inner portion of the workpiece [63] is concentrically provided with a rigid mandrel [65], a rigid core The outer surface of the shaft [65] is in contact with the inner wall of the workpiece [63], and the outer portion of the workpiece [63] is concentrically provided with a rigid collar [62], and the inner surface of the rigid collar [62] is in contact with the outer wall of the workpiece [63].

4. The tubular material high-pressure shear deformation device according to claim 2, wherein: the inner surface of the rigid collar [62] and the outer surface of the rigid core shaft [65] are subjected to texturing treatment to increase the workpiece [63]. The friction between.

5. The tubular material high-pressure shear deformation device according to claim 2, wherein: a clearance fit is used between the upper anvil [61] and the rigid collar [62]; the rigid mandrel [65] and the lower anvil A gap fit is used between [64].

6. The tubular material high-pressure shear deformation device according to claim 2, wherein: one of the rigid mandrel [65] or the rigid collar [62] is rotatable, and the other is fixed, rotating. The angle is unlimited.

7. The tubular material high pressure shear deformation device according to claim 2, wherein: the rigid ring sleeve [62] can adopt a single layer mold design, a prestressed winding mold design or a prestressed multilayer mold design.

8. The tubular material high-pressure shear deformation device according to claim 2, wherein: the upper anvil [61] and the rigid mandrel [65] are two independent parts or are integrated into a part. The upper anvil [61] is an overall design or a combined design. When the overall design is adopted, the ends of the upper anvil [61] and the lower anvil [64] respectively conform to the shape of the upper and lower end faces of the workpiece [63]. The annular boss has a combined design, the anvil includes an anvil body and an annular washer, and the annular gasket cross-section conforms to the shape of the end surface of the workpiece [63].