JP2003311320A - Plastic forming device, and plastic forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plastic forming device and a plastic forming method for forming substantially uniform distortion while minimizing the deposit of a work on bent parts. <P>SOLUTION: When performing plastic forming by forcibly distributing a work 37 in flow passages 33a-33c of a cylindrical container, a plurality of pairs of bent parts 34 and 35 having an angle of inclination below 90° are formed in the flow passages, and shearing force is applied to the work at the bent parts a plurality of times. Since the plurality of bent parts are present, the shearing force is applied a plurality of times by a single press-feed of the work, the distortion generation efficiency is improved, the quantity of the work to be deposited on an inner surface of the bent parts is reduced, and a uniform distortion is given to the work. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic working apparatus and method for obtaining a material in a predetermined strain state according to the purpose of predetermined texture control such as metal texture control and crystal grain refinement by plastic working. More specifically, the present invention relates to a plastic working apparatus and method capable of forming a substantially uniform strain by minimizing a fixed amount of a workpiece to a bent portion that causes a strain.

[0002]

2. Description of the Related Art Conventional plastic working is carried out by subjecting a work material to strong working such as rolling, extrusion and drawing. When the plastic working is carried out, the formation of a so-called texture is inevitable. The resulting material exhibits anisotropic material properties.
The anisotropy may be positively utilized, but when the anisotropy is not desired, a treatment for removing the anisotropy is performed by heat treatment or the like. Therefore, an isotropic material cannot be obtained in the plastic working state.

On the other hand, recently, researches and developments have been actively carried out to achieve the refinement of crystals by subjecting it to strong working, and for example, it is disclosed as a review in the following literature (for example, FJHumphr.
eys, PBPrangnell and R.Priestner, "Fine-Grained A
lloys by ThermomechanicalProcessing ", Proceedings
of the Fourth International Conference on Recrysta
llization and Related Phenomena, edited by T.Sakai
and HG Suzuki, 1999, p69).

Among the strong working methods disclosed in the above document, a high shear strain applying process utilizing a curved flow path (die cavity) having a certain angle such as a right angle is drawing attention. This process is based on ECAP (equal-channel-an
gular-processing) method or ECAE (equal-channel-an
gular-extrusion) method, which is a method of plastically working a work material so as to give a high shear strain at the angle part by supplying a solidified material into a right-angled or inclined die cavity and performing extrusion-drawing. It has been proved that grain refinement can be achieved by strong working. However, in the plastically machined work material, particles that are biased in one direction are becoming finer or ribbons are formed.Therefore, in order to obtain isotropic refined crystals, the direction of the work material is set at an inclination angle of 90 °. It is disclosed by Z. Horita et al. In P301 of the above-mentioned document that the process needs to be repeated at least four times (rotation by 90 degrees).

The ECAP method will be described with reference to FIGS. 10 and 11. FIG. 10 is a perspective view of a die that can be used in the ECAP process, and FIG. 11 is an enlarged vertical sectional view of a main part of FIG. Figure 10
As shown in FIG. 3, the rectangular parallelepiped die 1 is provided with a die cavity (flow passage) 3 that descends from the opening 2 on the upper surface, bends at a right angle to the right, and then reaches the side surface of the die 1 and opens. ing. When a rectangular parallelepiped workpiece 4 is press-fitted into the die cavity 3 from the opening 2 using a plunger (not shown) while heating the die 1, the workpiece is at a right angle in the die cavity 3. The bending portion 7 corresponding to a portion receives a shearing force and is deformed as shown in FIG. 11 according to the shape of the corresponding die cavity 3.

[0006]

At this time, a slip band is generated in the crystal grains of the material 4 to be processed in the compression field, and the old crystal grains are sheared and broken, so that the grains deviated in a certain direction are refined. Then, when a force is further applied or a tensile stress is applied to the work material 4 in the state of FIG. 11, it is taken out as the plastic work material 6 from the opening 5 on the side surface of the die 1. According to this method, an aluminum alloy or magnesium alloy having a high shear strain that has been actually plastically processed in the order of 1 μm has been obtained on a laboratory scale, and it can be said that this is an effective method. However, in the plastically machined work material, since grain refinement biased in a certain direction occurs as described above, in order to obtain an isotropic refined crystal, the direction (phase) of the work material is changed. It is necessary to perform plastic working again through the die 1.

As described above, although the ECAP method has the advantage that the flow direction of the material to be press-fitted is limited to two directions and that high shear strain can be applied to the material to be processed by the repeated steps, it is possible to obtain an isotropic refined crystal. There is a drawback that the process is too complicated to obtain and the productivity is not improved. Further, with a material having poor formability such as magnesium, it is necessary to perform plastic working in a heated state, but if the above-mentioned steps are repeated, deterioration due to oxidation of the material will occur.

Further, it is desirable that the strain imparted to the work material is evenly distributed throughout the material, but the degree of the strain is not necessarily high, and the strain depending on the intended use of the work material is imparted. It is desirable to be able to. In the above-mentioned ECAP method, since the material is subjected to shearing force at a right angle portion in the die cavity 3 to change into the shape of the corresponding die cavity 3, a high stress is generated to generate a high strain and a material having a relatively small strain. Is difficult to obtain by plastic working. Thus, conventionally, it is practically possible to obtain a work material having an arbitrary strain amount from a low strain state to a high strain state and to obtain a plastically worked work material in a high strain state by a relatively simple operation. It was impossible. Therefore, the present invention is to perform a plastic working of a work material by a simpler method to obtain a predetermined performance, particularly a work material having an arbitrary strain amount from a low strain state to a high strain state, or a high strain or isotropic fine grain. A plastic working apparatus and a plastic working method capable of obtaining a work material having a crystallized crystal, and in particular, an amount of sticking of the work material to a bent portion is minimized so that a substantially uniform strain can be formed. An object is to provide a plastic working apparatus and method.

[0009]

SUMMARY OF THE INVENTION The present invention is an apparatus for performing plastic working by forcibly flowing a material to be processed through a flow path of a cylindrical container, wherein the flow path has a plurality of bending angles of less than 90 °. Forming part and applying a shearing force to the work piece a plurality of times at the bent part, and a tubular shape having a plurality of bent parts having an inclination angle of less than 90 °. The workpiece is forcibly flowed through the plastic working device in which the flow path of the container is formed to perform the plastic working, and the workpiece is processed by applying a shearing force to the workpiece a plurality of times for each of the plurality of bent portions. In the present invention, a plurality of barrier bodies may be installed on the inner surface of the tubular container flow path.

The present invention will be described in detail below. Materials to be subjected to plastic working of the present invention include pure metals such as aluminum, magnesium, iron and titanium, and alloys or intermetallic compounds thereof, ceramics, resins and hybrid materials which are composites thereof. . The size of the material to be processed is not particularly limited and may be set appropriately according to the required application. In the present invention, a material to be processed (material to be processed) made of such a material is preferably heated and plastically processed with a flow path of a cylindrical container having a plurality of bent portions with an inclination angle of less than 90 °. Press into the flow path of the device using a plunger. The size of the plastic working device is not particularly limited, but the preferred size varies depending on the size of the work material. For example, the size of the plastic working device (die part to be described later) when performing the plastic working of a cylindrical work piece with a diameter of 15 cm and a height of 30 cm is 50 to 200 cm in length, 50 to 200 cm in width and height, and height. The length can be selected in the range of 50 to 200 cm.

The work material press-fitted into this apparatus is first shown in FIG.
And in the same manner as in the case of the conventional ECAP method shown in 11,
The first bending portion receives the first shearing force and is deformed according to the shape of the corresponding flow path to generate the first strain, which is accumulated in the work material. The work material thus subjected to the first shear deformation is further deeply pressed into the flow path by the plunger or the like and reaches the second bent portion. In the second bent portion as well, similarly, the second shearing force is applied and the second bent portion is deformed in accordance with the shape of the corresponding flow path to generate the second strain.
Strains are combined and accumulated in the work material. In the case of a device having three or more bent portions, a third strain is further generated in the work material at the third bent portion, and this is performed up to the last bend portion, and the work material is subjected to a plurality of shearing forces. Distortion due to force occurs.

In the present invention, at least a part of the inclination angle at the plurality of bent portions is formed to be less than 90 °. That is, some of the plurality of bent portions may have an inclination angle of less than 90 ° and the other inclination angles of 90 ° or more than 90 °. Here, the tilt angle means an angle difference between an angle formed by two flow paths forming a bent portion and a linear shape of the two flow paths. If the angle of inclination is 90 °, the load is applied vertically to the bent portion and sticking occurs. On the other hand, when the inclination angle is less than 90 °, the load is obliquely applied, so that the material to be processed is circulated smoothly in the flow path, which reduces the amount of sticking.
Or substantially zero. In this case, the adjacent bent parts form a pair of bent parts, and the total angle of inclination of the bent parts is 90
It is desirable to set it to be °. 90 in the present invention
The angle less than 0 includes an angle close to 90 ° as much as possible, and if the inclination angle is slightly less than 90 °, the effect peculiar to the present invention that the number of materials to be processed is reduced occurs.

The larger the number of bent portions or pairs of bent portions, the more the shearing force is applied by a single press-fitting operation of the material to be processed, and the more strain can be generated, but the resistance in the flow passage is increased. Therefore, it becomes difficult to press the work material into the device. Therefore, the number of bent portions or bent portion pairs is appropriately set in consideration of the required strain amount and press-fitting of the workpiece. The sum of the tilt angles of the bent parts is 90
When set to °, if the number of pairs of bent parts is an even number, it is possible to direct the lead-in part and the lead-out part of the work piece in the same direction, which is preferable for saving space, and the direction in which force is applied is the same The stability of the device is improved as compared with the case of being on a line and being in a right angle direction. When forming two adjacent bent portion pairs having a total inclination angle of 90 °, there are a form in which the bending directions are the same and a form in which the bending directions are opposite.

When the bending directions are the same, the cross-sectional shape of the flow path becomes a "U" shape, and when the bending directions are the same, two "L" are combined in the reverse direction. When the bending directions are the same, the work material receives shearing force from the same direction at the two adjacent bending parts, but when the bending directions are the same, strain is almost uniform due to shearing force from the opposite direction. A work material dispersed in the can be obtained. In this way, by appropriately setting the number of bent portions or bent portion pairs, the inclination angle, and the direction, it is possible to generate a desired strain in the obtained workpiece. In the conventional ECAP method, the shearing force is applied only once by press-fitting the material to be processed once, but in the present invention, since there are a plurality of bent portions or bent portion pairs, the shearing force is applied a desired number of times. be able to.

Therefore, as in the prior art, in order to obtain an isotropic refined crystal, the direction of the work material should be at least 4 at an inclination angle of 90 °.
There is no need to repeat the process by changing the number of times (rotation by 90 °), and for a device having four bending parts or a pair of bending parts, a device having two bending parts with one press-fitting operation. However, by performing the press-fitting operation once and pressing the workpiece out while changing the direction of the workpiece, a workpiece having substantially the same strain as when the conventional four-step process is repeated can be obtained. As described above, when the angle of inclination of the bent portion is less than 90 °, the amount of sticking decreases as the angle of inclination decreases, but the amount of surface distortion generated also decreases. When the angle of inclination of the bent portion is 90 °, the amount of strain generated is almost constant, and even if the number of bent portions is increased, the amount of strain generated only increases to an integer multiple of that amount, and an arbitrary amount of strain is generated. I can't. On the other hand, when the tilt angle is less than 90 °, the tilt angle and the strain generation amount are substantially proportional to each other, and therefore the strain generation amount can be controlled by adjusting the tilt angle. Therefore, it is sufficient to determine the inclination angle of the bent portion pair in consideration of the correlation between the required strain amount and the uniformity of the tissue (decrease in the adhered amount). This can be dealt with by increasing the number of copies.

As described above, according to the present invention, a work material having a desired strain can be obtained by setting a plurality of bent portions or a pair of bent portions in the flow channel. If the barrier body is formed asymmetrically, a work material having a desired strain can be obtained more easily and reliably. Each barrier body is installed so as to close a part of the flow path of the cylindrical container, and the work material press-fitted into the flow path of the cylindrical container is brought into contact with the barrier body to change the flow path and installed. In the multiple stress field generated in the step of passing the flow path constituted by the barrier body and the inner wall of the cylindrical container, the plastic working of the work material is performed,
In addition to the above-described strain formation at the bent portion or the bent portion pair, strain is generated in the work material.

Since a plurality of barrier bodies are formed, the work material forms such a multi-stress system each time it contacts each barrier body, and plastic working is performed.
Therefore, plastic working is performed the same number of times as the number of barrier bodies, and a more uniform and finer structure can be obtained as the number of barrier bodies increases. Furthermore, since all barrier bodies are arranged asymmetrically in the cross section of the cylindrical container, the work material being plastically deformed in different directions by each barrier body, and the work material being machined is deformed in the cylindrical container. It is possible to change the direction of the stress applied to the material to be processed without re-press-fitting into the flow path. Here, the "cross section" in the cross section of the tubular container means a surface perpendicular to the inner wall of the tubular container. The barrier body of the present invention is not particularly limited as long as it has a shape that closes a part of the flow path of the cylindrical container as described above, but the cross section has an arc shape, a rectangle, a polygon shape, or a combination thereof. The surface shape is preferably a polyhedron shape or a curved surface shape such as a sphere and an ellipse.

The barrier body is installed so as to be in contact with the inner surface of the tubular container, and the barrier body may be formed integrally with the tubular container or fitted into a hole formed in the tubular container. Alternatively, it may be adhered to the inner surface of the cylindrical container having a flat or curved shape with an adhesive. Further, since the barrier body comes into contact with the work material and functions to change the flow direction, contact with the barrier body may cause a void in the work material or a defect in the work material. It is desirable to take care not to do so. For example, a portion corresponding to a corner of the barrier body is slightly curved to prevent damage to the workpiece to be processed. Further, it is preferable that the work piece to be processed is brought into smooth contact with the barrier body, and if a so-called dead space occurs, the processing efficiency decreases. Each barrier body may be any material as long as it does not react with the work material and has resistance to the work material.

The material to be processed used in the present invention preferably has a normal shape such as a rectangular parallelepiped shape or a cylindrical shape before the processing, and after the processing, the same shape as the original shape or a treatment close to the original shape is performed. It is preferable that the shape is easy. When plastic working is carried out with a device having a tubular flow path as in the present invention, it is obtained from the device as a processed material that has been plastically processed with the same cross-sectional shape as the tubular flow path. A flow path can be obtained as a cylindrical work material, and a square tubular flow path can be obtained as a rectangular parallelepiped work material. If you want to obtain a workpiece with a shape other than these, at the end of the device,
Alternatively, a predetermined mold is installed continuously with the apparatus to adjust the shape. However, the mere extrusion process makes it difficult for the work material deformed by the strong process to return to the original shape and size. In order to more smoothly return to the original shape or a shape close to it, it suffices to apply a large stress to the rear side of the work piece rather than the front side, and in order to achieve this, for example, a precision hydraulic device is added to the device of the present invention. It suffices to install two of them and drive them while linking both hydraulic devices to adjust the stress. With such a configuration, a dead space is less likely to occur between the workpiece to be processed and the tubular container.

If a large number of barrier bodies are installed, they will undergo a large number of plastic workings, and a single extrusion process is carried out by the conventional ECAP method or the like by press-fitting the work material to be worked-single plasticity. It is possible to obtain substantially the same processing effect as that of repeating the processing-removal of the processed material-reinjection of the processed material. Therefore, it becomes possible to obtain a plastic-worked material having a predetermined characteristic by press-fitting the material into the flow path of the cylindrical container once. However, if the specified characteristics cannot be obtained by a single press-fitting plastic working process, it may be taken out from the device as before and press-fitted again into the tubular flow path of the device. The structure is such that the barrier material is separated from the area where the barrier body is installed, but the work material still in the flow path is returned to the area where the barrier body is installed while applying pressure, so that Plastic working may be performed. In this case, plastic working, that is, higher strain proceeds, and a work material having predetermined characteristics is obtained.

Due to the peculiarity that the barrier body is installed in the flow path of the tubular container, a dummy material is used in addition to the material to be processed in order to perform the reciprocal extrusion processing.
Since this dummy material itself is not intended for processing, it may be a material other than the material to be processed, has an appropriate hardness, and extrudes the material to be processed that has been deformed in the tubular flow path outside the barrier body installation area, In addition, it has a role of deforming into a shape corresponding to the inner surface of the flow path. However, since this dummy material itself also undergoes plastic working by contacting the barrier body, if the material to be processed is the same as the material to be processed or a material that can be used as the material to be processed, the plasticity is equal to or slightly inferior to the material to be processed. Processed under processing conditions to obtain a plastically processed material with a certain amount of strain and isotropic refined crystals. Depending on the application, high strain and isotropic refined crystals may be used in the same way as the original work material. It can also be used as a plastically worked material having a. Then, not only a work material having a high strain can be obtained, but a predetermined strain degree can be obtained by adjusting the number and shape of the barrier body (degree of blocking the flow path), the number of reciprocations, and the like. It is possible to obtain a work material in which the strain is almost uniformly dispersed.

Next, the theoretical analysis and model experiment of the plastic working of the work material when setting the barrier body will be described with reference to the diagram of FIG. In FIG. 1, the cross section of the flow path is a rectangular parallelepiped, the barrier body is installed on the inner wall of the upper surface of the flow path, and the work material is press-fitted from the left side of the figure into a cylindrical container in which the barrier body is installed on the inner wall of the lower surface, and plastic working is performed from the right side. The model which takes out a to-be-processed material is shown. It should be noted that in FIG. 1, the shaded portions at both ends and the polygonal line portion (including an arrow in the figure) connecting the both indicate the movement of a minute portion of the workpiece. The barrier body has a triangular cross section as shown in the drawing, and has a shape of a triangular prism extending in the direction perpendicular to the drawing, and the sloped portion of the triangle is in contact with either the upper or lower inner wall of the flow path.

Using this model, the strain experienced by the metal will be explained by the upper bound method. This upper bound method makes the following assumptions. The cylindrical container shall be rigid. Metals follow Mises's stress-strain rate law (a metal is a rigid perfect plastic body that does not elastically deform, maintains a constant yield stress value, and does not work harden). The deformation of the metal is kinematically acceptable (at the interface where two regions are adjacent, the vertical velocity components of both regions with respect to this interface are equal to each other). The contact surface between the cylindrical container and the metal is a velocity discontinuity surface. The inside of the cylindrical container is filled with metal. The friction loss at the interfaces between the cylindrical container and the metal and between the metal and the barrier body is not considered.

Further, in FIG. 1, as described above, the flow path of the cylindrical container is a rectangular parallelepiped in which all four corners are right angles, and therefore the metal undergoes plane strain deformation in the flow path of the cylindrical container. In FIG.
The triangular area BCD represents a barrier body which is an isosceles triangle having sides BC and CD equal to each other. Similarly, the triangular area B'C '.
D'indicates a barrier body. Both barrier bodies have the same shape and size. Point D ′ of the barrier body with respect to the barrier body
Are arranged at axial positions such that ∠D′CI ′ = α / 2. The distance between the inner walls of the cylindrical containers facing each other is t0, and the vertical distance between the vertex C of the barrier body and the inner wall of the container facing it is t1.

Using the shear boundary (boundary surface subjected to shearing), the rigid body movement (only translation without deformation) and deformation of the metal are divided into the following regions for calculation (see FIG. 1). A. Region I: rigid body movement (non-deformed region). B. Shear boundary Γ1 ... Represents a boundary surface where the metal from region I undergoes shear deformation on this surface and turns into a convergent flow in region II. Shear strain due to velocity discontinuity along Γ1. C. Deformation region II: Represents a region that is subject to distortion due to a convergent flow up to Γ2 toward the apex O of the sector. D. Shear boundary Γ2: A boundary surface where a metal that has undergone a convergent flow in the area II undergoes shear deformation on this surface and changes to rigid body movement in the area III. The metal experiences shear strain due to velocity discontinuities along Γ2. E. Region III: Performs rigid body movement (translation parallel to inner wall of container). F. Shear boundary Γ3 ... A boundary surface where the metal in the region III undergoes shear deformation on this surface and changes into rigid body movement in the region IV. The metal experiences shear strain due to velocity discontinuities along Γ3.

G. Region IV: Rigid body movement is performed (the metal translates in a parallel region constituted by the surface CD of the barrier body and the surface D'C 'of the barrier body). H. Shear boundary Γ3 ′ ・ ・ ・ From rigid body movement in region IV to region II
The boundary surface that changes to the rigid body movement of I'is shown. The metal experiences shear strain due to velocity discontinuities along Γ3 '. I. Region III ': Performs rigid body movement (translation parallel to inner wall of container). J. Shear boundary Γ2 '... Represents a boundary surface that changes from rigid body movement in region III to diffusive flow in region II'. Shear strain is incurred due to velocity discontinuities along Γ2 '. K. Deformation region II '... Indicates a diffusion flow region from the shear boundary Γ2' to the metal Γ1 'on the radial line passing through the fan-shaped apex O'. This region is distorted by the diffuse flow. L. Shear Boundary Γ1 ′ represents a boundary surface in which a metal that has undergone a diffusive flow in a region II ′ undergoes shear deformation and changes into a rigid body movement in a region I ′. Shear strain is incurred due to velocity discontinuities along Γ1 '. M. Region I '... Rigid body movement is performed (deformation end region).

Next, the strain that the metal undergoes in each region or boundary will be described. a. Strains in deformation regions II and II ′ The value of the average equivalent strain ε _II due to the convergent flow in the deformation region II is as follows. ε _II = (2/3 ^1/2 ) × ln (t0 / t1) × Ε (3 ^1/2 / 2, α) / sin α (1) where Ε (3 ^1/2 / 2, α) / sin α is the elliptic integral value. The average equivalent strain ε _II ′ due to the diffusive flow in the deformation region II ′ is equal to the average equivalent strain in the region II, and is given by the following equation. ε _II = ε _II ′ (2)

B. Arc-shaped shear boundary surfaces Γ1, Γ2, Γ2 '
And average shear strains at Γ ₁ ′ The average shear strains γ ₁ , γ ₂ , γ ₂ ′ and γ ₁ ′ at the arcuate shear boundary surfaces Γ ₁ , Γ ₂ , Γ ₂ ′ and Γ ₁ ′ are obtained as follows. The equivalent shear strain γ ₁ at the shear boundary surface Γ ₁ is given by equation (3). It is given by γ ₁ = (1/3 ^1/2) × [tan (alpha / 2)] (3) shear boundary .GAMMA.2, equal equation (4) to the average shear distortion gamma ₁ in .GAMMA.2 'and .GAMMA.1' . γ ₂ = γ ₂ ′ = γ ₁ ′ = γ ₁ (4) c. Strain at Plane Shear Boundaries Γ3 and Γ3 ′ Shear strain γ ₃ at Shear Boundary Γ3 is given by equation (5). γ ₃ = (2/3 ^1/2 ) × [tan (α / 2)] (5) The strain γ ₃ ′ at the shearing boundary Γ ₃ ′ is also equal to γ ₃ and equation (6)
Given in. γ ₃ ′ = γ ₃ (6)

[0029] d. Metal covers from region I to region I '
Distortion Equations (1) to (6) can be combined to calculate the strain at the characteristic region and the shear interface. i) If the value of the average equivalent strain is ε cd, then ε cd is obtained from the sum of the strain equation (1) in the region II and the strain equation (2) in the region II ′.
Can be calculated by the following formula. ε cd = (4/3 ^1/2 ) × ln (t0 / t1) × Ε (3 ^1/2 / 2, α) / sin α (7) ii) Arc-shaped shear boundary surfaces Γ1, Γ2, Γ2 'and Γ1 Let εsp be the sum of the distortions of ′, from the sum of equations (3) and (4), ε
sp can be calculated as shown below. εsp = (4/3 ^1/2 ) × [tan (α / 2)] (8) iii) The sum of strains at the plane shear boundary surfaces Γ3 and Γ3 ′ is εp
Then, εp can be calculated as in the following equation by the equations (5) and (6). εp = (4/3 ^1/2 ) × [tan (α / 2)] (9)

Next, the total sum εsum of strains is calculated from these values.
When calculated, it becomes like formula (10). εsum = (4/3^1/2)
× ln (t0 / t1) × Ε (3^1/2/ 2, α) / sin α + (8 / Three^1/2) × [tan (α / 2)] (10) And it is assumed that the inclination angle α of the barrier body and α is 20 °.
And elliptic integral (Ε (3^{1 / 2}The value of / 2, α) / sin α) is
It becomes 1.005. And ln (t0 / t1) = ln (1 / 0.75) = 0.29
Is. Therefore, εsum = 0.67 + 0.81 = 1.48, and this
Use the tubular container shown in Figure 1 to
In metal calculated by the upper-bound method model for elastic processing
The distortion that is accumulated in is obtained.

The strain in the heavy working with a cross-section reduction rate of 99% corresponds to about 4.6. Therefore, the plastic working of the model in Fig. 1 is
A metal having a strain of more than 4.6 can be manufactured by repeating the process once, for example, by setting the number of barrier bodies to four and reciprocating the plunger (not shown) once or by setting the number of barrier bodies to eight. Further, when the tilt angle α in the above-mentioned calculation formula is brought close to 0, the distortion becomes small. Since this inclination angle is continuously changed, a metal having an arbitrary strain can be provided by adjusting this inclination angle. Also, in this model, the barrier body is installed only on the top and bottom, but it is installed on the four sides of the rectangular parallelepiped, or the cylindrical container is made cylindrical and the barrier body is radially installed on the inner wall to further disperse the strain. It can also be made uniform.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a plastic working apparatus and method for a workpiece according to the present invention will be described in more detail with reference to the accompanying drawings. 2a and 2b are a series of vertical cross-sectional views illustrating the procedure for plastically working a workpiece to be worked by an example of the device of the present invention. As shown in FIGS. 2a and 2b, a rectangular parallelepiped die 31 has a first flow path 33a that descends from an opening 32 on the upper surface and reaches near the lower end, and the lower end of the first flow path 33a is formed by bending rightward. A second flow path 33b, and a third flow path 33b formed by bending the right end of the second flow path 33b upward.
The flow path 33c is provided.

A first bent portion 34 is formed at a joint portion between the first flow passage 33a and the second flow passage 33b, and the bent portions have inclination angles of φ ₁ and φ ₂ respectively in the illustrated example. It is configured as a certain first bent portion pair, and φ ₁ = φ ₂ = 45 °. Similarly, the second
A second bent portion 35 is formed at a joint portion between the flow path 33b and the third flow path 33c, and the bent portion is configured as a first bent portion pair having inclination angles of φ ₃ and φ ₄ , respectively. And φ ₃ = φ ₄ = 45 °. Barrier members 36 having obtuse isosceles triangular cross-sections are formed on the inner walls on both sides of each of the channels 33a to 33c.

At the start of processing shown in FIG. 2a, the first flow path 33
The base end side of the work piece 37 filled in a and the second flow path 33b is located near the surface of the die 31. While the die 31 is being heated, the work material 37 is pressed into the flow path 33a through the opening 32 by using a plunger or a mold 38, the work material 37 (for example, a point of the work material 37). 37A) is the first channel 33a
After being subjected to stress by the barrier bodies 36 on the inner walls on both sides of the and causing distortion, the first bend portion 34 is reached. The first bent portion 34 is 45
A pair of bent portions bent at an inclination angle of 0 ° is formed, and the work material 37 receives a shearing force of 2 degrees and is deformed in the horizontal direction according to the shape of the corresponding bent portion 34 to cause distortion. , The workpiece 37
Point 37A reaches the inside of the second flow path 33b.

As shown in FIG. 2b, when a dummy material 39 is inserted between the mold 38 and the work material 37 and the mold 38 is pushed down, the point 37A in the work material is changed to the second bent portion. 2b, after receiving the shearing force and deforming in the vertical direction to generate further strain as in the case of the first bending portion 34, the third bending portion of FIG.
The point 37A in the flow path 33c is reached. Thus, FIGS. 2a and 2
In the example of b, the point 37A in the material 37 to be processed is subjected to shearing force at the two bent portions 34 and 35 by a single press-fitting by the die 38 to generate strain. Different from the conventional ECAP method, it has multiple bends, so it is possible to generate the desired shearing force and the resulting strain with one press-fitting, without removing the workpiece from the device. Shear strain can be generated in the directions intersecting with each other. Also the tilt angle
When a shearing force is applied at a single bent portion of 90 °, the work material adheres to the surface of the bent portion and uniform strain cannot be added, whereas in the example of FIG. Since the parts 34 and 35 are composed of a pair of bent parts each having an inclination angle of 45 °, it is not always possible to prevent sticking completely, but the sticking amount can be greatly reduced and a relatively uniform strain can be obtained. A work material having is obtained.

3a and 3b are a series of longitudinal sectional views showing another example of the apparatus for plastically working a work material. In the apparatus of FIGS. 3a and 3b, the channels of the vertically long die 41 are two vertically long first long channels 42a and second vertically long channels 4a extending in different directions.
2b and a short channel 42c connecting both long channels.
The first bent portion 4 is provided at the joint between the first long flow path 42a and the short flow path 42c.
3 is formed, and the bent portion is configured as a first bent portion pair whose inclination angles are φ ₅ and φ ₆ , respectively in the illustrated example, and φ
₅ = 30 °, is set to φ ₆ = 60 °. Similarly, the short channel 42c
A second bent portion 44 is formed at the joint between the second long flow path 42b and the second long channel 42b, and the bent portion is configured as a second bent portion pair having inclination angles of φ ₇ and φ ₈ , respectively. ₇ = φ ₈ = 45 °. When the workpiece 45 is press-fitted into the first long flow path 42a using the die 45 while heating the die 41, the workpiece 46
Reaches the first bent portion 43 in which a pair of bent portions is formed, and the work material 46 receives a shearing force of 2 degrees and is deformed and deformed in the horizontal direction according to the shape of the corresponding bent portion 43. Occurs.

When the die 45 is further pushed down, the workpiece material 46 moves horizontally in the short flow path 42c and reaches the second bent portion 44, where it receives shearing force and the corresponding bent portion is received. Depending on the shape of 44, it deforms in the vertical direction to generate strain, and further moves downward and is taken out from the tip of the second long flow path 42b. Figure 3
Also in the example, since the first bent portion 43 and the second bent portion 44 are composed of a pair of bent portions each having an inclination angle of less than 90 °, the sticking can be significantly reduced, and the fixing is relatively uniform. A work material having strain can be obtained.

4 to 6 are vertical sectional views showing dies that can be used in the present invention. The die 51 of FIG. 4 has a first flow path 53 that descends from an opening 52 on the upper surface and reaches near the lower end.
a, a second flow path 53b formed by bending the lower end of the first flow path 53a to the right by 90 °, and a right end of the second flow path 53b is bent upward with an inclination angle φ ₉ (≈30 °). Inclination angle φ
Bent at ₁₀ (≈60 °) to form a bent pair 54,
A third flow path 53c is formed upward from the bent portion pair 54. At the start of processing, the first channel 53a and the second channel 53a
The base end side of the workpiece 55 filled in b is located near the surface of the die 51. While heating the die 51, the work piece 55 is opened by using a plunger or a mold 56.
When press-fitted into the flow path 53a from 52, the work material 55 reaches the intersection of the first flow path 53a and the second flow path 53b having an inclination angle of 90 °, and further passes through the second flow path 53b to fold. Reach 54.
In the bent portion pair 54, strains corresponding to the inclination angle φ ₉ and the inclination angle φ ₁₀ are generated and taken out from the die 51 through the third flow path 53c.

FIG. 5 shows a die which is a modification of FIG. 4, and the same members as those in FIG. In the die 51A shown in FIG. 5, the inclination angle φ is used instead of the bent portion pair shown in FIG.
₁₁ (≈45 °) individual bent portions 54A are formed.
A strain of less than half of the strain at the bent portion with an inclination angle of 90 ° is generated at 54A, and the die 51A is passed through the third flow path 53d extending diagonally.
Taken from. In this example, by adjusting the inclination angle (0 ° to 90 °) of the bent portion 54A, distortion in the range of 1 to 2 times less than the distortion at the bent portion having the inclination angle of 90 ° is generated. be able to.

In the die 61 shown in FIG. 6, four flow paths 62a,
62b, 62c and 62d are the first bent portion 63a and the second bent portion in this order.
63b and the third bent portion 63c (inclination angle φ ₁₂ , inclination angle φ ₁₃ and inclination angle φ _{14 respectively} ) (φ ₁₂ =
φ ₁₃ = φ ₁₄ = 60 °), the work piece introduced through the opening 64
Reference numeral 64 denotes each of the bent portions 63a, 63b and 63c, which generates less strain than in the case of 90 ° bending, but is processed from the die 61 through the fourth flow path 62d after being processed with a small adherence amount of the work material. Be done.

Next, the principle of strain generation by the barrier body will be described with reference to FIGS. 7a to 7c. The plastic working apparatus for a work material shown in FIGS. 7a to 7c is composed of a tubular container 12 having a rectangular tubular flow path 11, and is slightly spaced above the center of the flow path 11 to form the tubular shape. Two triangular prism-shaped barrier bodies 13 integrally formed with the container 12 are arranged in a raised manner.
Two barrier bodies 13 in the shape of a triangular prism integrally formed with the tubular container 12 are erected alternately with the upper barrier body 13 while being slightly spaced below the central portion of the flow path 11. In the example of FIG. 7a, a total of four barrier bodies 13 are installed in the rectangular tubular flow path 11. Although the barrier body 13 has a triangular prism shape in the illustrated example, it may be a semi-cylindrical cylinder or the like, and is formed by a gentle curved surface with as few corners as possible,
It is desirable not to damage the material to be processed.

As shown in FIG. 7a, a first plunger 20a is slidably installed along the inner surface of the rectangular tubular flow passage 11 on the left side of the inside of the rectangular tubular flow passage 11. The pressing surface 20b is positioned so as to come into contact with the dummy material 21 that is press-fitted in advance in the flow path in which the four barrier bodies 13 are installed. Next, the work piece 22 to be processed in the form of a prism such as a magnesium alloy is supplied into the rectangular tubular flow path 11 from the opening on the right side, and the work piece 22 is press-fitted by the second plunger 23a having the pressing surface 23b. And extruding under heating or at room temperature.

Workpiece is press-fitted by the second plunger 23a.
22 is a barrier body 13 on the right side of the lower inner wall surface shown in FIG. 7b.
To contact. Since the barrier body 13 is deviated to the lower side in the rectangular tubular flow passage 11, the work piece 22 to be processed is the rectangular tubular flow passage 11
Move the upper half of the inside. The material 22 to be processed subsequently contacts the barrier body 13 on the right side of the upper inner wall surface, and moves in the lower half of the rectangular tubular flow path 11. Further, the work material 22 to be processed contacts the remaining two barrier bodies 13 and undergoes similar processing, and finally the work material 22 corresponds to the barrier body 13 and the inner surface of the flow passage 11 of the tubular container 12. It deforms into the shape (Fig. 7b).

When the first plunger 20a is moved to the right in the drawing from the state of FIG. 7b, the work material 22 in which the dummy material 21 is deformed is moved to the right while being pressed. At this time, the deformed work material 22 comes into contact with each barrier body 13 again and is deformed to accumulate strain. The work piece 22 that has finished contacting the barrier body 13 further moves to the right and contacts the inner wall of the flow path 11 to be molded and returns to its original shape (FIG. 7c). At this time, the dummy material 21 returns to the shape shown in FIG. 7c. At this time, it is desirable to balance the moving speeds of the second plunger 23b and the first plunger 20a so that no gap is created between the container and the workpiece. In this way, the material 22 to be processed is restored from the deformation caused by the barrier body 13. In the state shown in FIG. 7c, if the material to be processed already has predetermined characteristics, it may be taken out from the opening at the right end of the rectangular tubular flow path 11 and used as a raw material.

However, in the plastic working by this single extrusion, when the work material 22 to be worked is not given sufficient characteristics, the second plunger 23a is moved to the left again again and the work material 22 is worked as shown in FIG. 7b. The work material 22 is deformed, and the first plunger 20a is further moved to the right. As a result, the material 22 to be processed is again deformed by the barrier body 13, and the characteristics are further improved. When the steps of FIGS. 7b and 7c are repeated a necessary number of times, sufficient properties are produced in the work piece 22 to be processed, and the work piece 22 can be taken out from the rectangular tubular flow path 11 and used for an appropriate purpose. Even when performing this repeated process,
It is not necessary to take 22 out of the cylindrical container 12, and even in the case of a work material that is easily oxidized, plastic working can be performed without degrading the characteristics of the material.

As can be seen from the above description, in the illustrated plastic working method, not only the work material 22 but also the dummy material 21 undergoes the plastic working by the barrier body 13 and has a predetermined characteristic or a characteristic close thereto. It becomes a material. Therefore, if a predetermined work material is used as the dummy material described as shown in the figure, a work material that is equivalent to or close to the original work material can be obtained. In the illustrated example, the dummy material is 1
Although an example in which one dummy is used is shown, two dummy materials may be located on both sides of the work material.

Further, in this example, the plastic working by four barrier bodies which are alternately positioned on the upper side and the lower side in the rectangular tubular flow path is exemplified, but the number and arrangement of the barrier bodies are not limited to this. For example, three barrier bodies can be arranged in a radial arrangement at 120 ° apart, and four barrier bodies can be arranged in a radial arrangement at 90 ° apart. In these cases, the work material is It can be deformed more favorably and a predetermined work material can be manufactured.

[Examples] Next, examples of the present invention will be described, but the examples and comparative examples do not limit the present invention.

Example As a test work material, Mg which is magnesium for wrought
-Al-Zn alloy AZ31 (Al3%, Zn1%) was used, and two-dimensional analysis software (GRADEForge2D) dedicated to forging was used for finite element simulation. In the analysis, plane strain elements were used, and the upper and lower molds were defined as rigid walls to model the experiment. In the analysis process, the upper die speed was set to 20 mm / sec, and 20 mm was press-fitted in 100 steps at this speed. Coulomb friction was used for friction. First, 10 dies having only a single bent portion and having an inclination angle (φ) of 0 ° to 90 ° (in steps of 10 °) were prepared and subjected to plastic working. Lattice points were added to the obtained workpiece by the width method, and the amount of strain at each lattice point was measured. The results shown in the graph of FIG. 8 were obtained. Then one die with a single bend with a tilt angle of 90 °, and the tilt angles of the bend pairs 10 ° + 80 °, 20 ° + 70 °, 30 ° + 60 °, 40 ° + 50 ° respectively
And 5 dies of 45 ° + 45 ° were prepared and subjected to plastic working. Lattice points were added to the obtained workpiece by the width method, and the amount of strain at each lattice point was measured. The results shown in the graph of FIG. 9 were obtained.

After the test, the amount of alloy adhered to each die was measured, and the die having a single bent portion with a tilt angle of 90 ° was the largest, and the tilt angle of the bent portion pair was 10 ° + 80 °, respectively. It decreased sharply with one die, and then gradually decreased, and the inclination angle of the bent pair became the minimum at the die with 45 ° + 45 °. On the other hand, as can be seen from FIG. 9, the amount of strain generation decreases as the difference between the inclination angles of the bent portions decreases. Therefore, it is understood that the inclination angle of the bent portion pair may be determined in consideration of the correlation between the required strain amount and the uniformity of the structure (decrease in the adhered amount).

[0051]

Industrial Applicability The present invention is an apparatus for performing plastic working by forcibly flowing a work material in a flow path of a cylindrical container, wherein a plurality of bent portions having an inclination angle of less than 90 ° are formed in the flow path. The plastic working apparatus (claim 1) is characterized in that a shearing force is applied to the work material a plurality of times at the bent portion. In the present invention, the conventional ECA has a plurality of bent portions, and the shearing force is applied only once by press-fitting the work piece once.
Unlike the P method, the shearing force can be applied multiple times by a single press-fitting of the material to be processed, so that the strain generation efficiency is improved. Larger strain can be generated by performing press-fitting a plurality of times. Furthermore, since at least part of the angle of inclination of the bent portion is less than 90 °,
As compared with the case where the inclination angle is 90 °, the amount of the work material that adheres to the inner surface of the bent portion is reduced, and uniform strain can be applied to the work material.

When a plurality of barrier bodies are installed on the inner surface of the tubular container flow path (claim 2), distortion is also generated by the barrier bodies, and distortion is generated together with the distortion due to the bent portion. The amount increases. Particularly, by devising the number and arrangement of the barrier bodies, a desired strain distribution can be generated in the work material. Therefore, in this aspect, it is possible to obtain a work material having an arbitrary strain amount from a low strain state to a high strain state. In the plastic working apparatus using this barrier body, multiple stress fields are generated, and multiple strains can be created in the work material (claim 3). Therefore, unlike the conventional ECAP method, multiple strains can be created without the need for a complicated process of taking out each process one by one, changing the phase of the work material and press-fitting the work material again. The barrier body may be movable along the inner surface of the tubular container flow path (claim 4), whereby the strain amount and the directionality of the strain can be adjusted without replacing the barrier body.

In the apparatus of the present invention, a pair of plungers are installed on both sides of the material to be processed in the flow path of the cylindrical container, and the relative movement of the plunger and the cylindrical container causes symmetry in the cross section of the cylindrical container. A workpiece flow can be formed (Claim 5). This relative movement includes movement of the plunger alone, the tubular container alone, or both, and any member may be moved as long as the workpiece to be processed comes into contact with the barrier body. When the curved portion is formed on the outside of the bent portion (claim 6), in addition to the angle of inclination of the bent portion being less than 90 °, the work piece is more likely to pass through the bent portion, The resistance of can be reduced. When the bent portions having a tilt angle of 90 ° are used as a pair of adjacent bent portions having a total tilt angle of 90 ° (claim 7), strain formation is facilitated.

In the method of the present invention, the material to be processed is forcedly flowed through the plastic working apparatus in which the flow path of the cylindrical container having a plurality of bent portions having an inclination angle of less than 90 ° is formed to perform the plastic working, A plastic working method (claim 8), characterized in that a shearing force is applied to the work material a plurality of times for each of the plurality of bent portions to cause distortion in the work material (claim 8). Since the shearing force is applied a plurality of times by a single press-fitting of the work material, it is possible to obtain the work material in which the strain generation efficiency is improved and the non-uniform strain due to the sticking of the work material is reduced.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an upper bound method model.

2A and 2B are a series of longitudinal cross-sectional views illustrating a procedure for plastically working a work material to be worked by an example of the device of the present invention.

3A and 3B are a series of vertical cross-sectional views illustrating the procedure for plastically working a work material to be worked by another example of the device of the present invention.

FIG. 4 is a vertical cross-sectional view illustrating a die that can be used in the present invention.

FIG. 5 is a vertical cross-sectional view illustrating another die that can be used in the present invention.

FIG. 6 is a vertical cross-sectional view illustrating still another die that can be used in the present invention.

7A to 7C are views for explaining the principle of strain generation by a barrier body.

FIG. 8 is a diagram showing a strain distribution when the tilt angle is changed in the example.

FIG. 9 is a diagram showing a strain distribution when the inclination angle of the bent portion pair is changed in the example.

FIG. 10 is a perspective view of a die that can be used in a conventional ECAP process.

11 is a partial vertical cross-sectional view of the device of FIG.

[Explanation of symbols]

31 die 33a, b, c flow path 34 first bent portion 35 second bent portion 36 barrier body 37 work material 39 dummy material φ _{1 to} φ ₄ inclination angle 41 die 42a, b, c flow path 43 first Bent part 44 Second bent part 46 Workpiece material φ _{5 to} φ ₈ Inclined angle 51 Die 53a, b, c Flow path 54 Bent part pair 55 Workpiece material φ ₉ , φ ₁₀ Inclined angle 51A Die 53d Flow path 54A Bent portion φ ₁₁ Inclination angle 61 Die 62a, b, c, d Flow path 63a, b, c Bent portion φ ₁₂ , φ ₁₃ , φ ₁₄ Inclination angle

   ─────────────────────────────────────────────────── ─── Continued front page    (71) Applicant 500453577             Kazuo Ichinose             1-24-2 Nishishinjuku, Shinjuku-ku, Tokyo Kogakuin University             Faculty of Engineering, Department of Mechanical Systems Engineering (72) Inventor Ryo Orihara             1-24-2 Nishishinjuku, Shinjuku-ku, Tokyo Kogakuin University             Faculty of Engineering, Department of Mechanical Systems Engineering (72) Inventor Naoki Niwa             1-24-2 Nishishinjuku, Shinjuku-ku, Tokyo Kogakuin University             Faculty of Engineering, Department of Mechanical Systems Engineering (72) Inventor Kazuo Ichinose             1-24-2 Nishishinjuku, Shinjuku-ku, Tokyo Kogakuin University             Faculty of Engineering, Department of Mechanical Systems Engineering (72) Inventor Hidefusa Takahara             1333-2 Hara-shi, Ageo-shi, Saitama Mitsui Mining & Smelting             Research Institute, Inc. (72) Inventor Nobuo Fujikura             407-9 Wakamatsucho, Wakaba Ward, Chiba City, Chiba Prefecture F-term (reference) 4E029 AA07 MA05 RA01 RA07

Claims (8)

[Claims] 1. An apparatus for performing plastic working by forcibly circulating a work material in a flow path of a cylindrical container, wherein a plurality of bent portions having an inclination angle of less than 90 ° are formed in the flow path, and the work is processed. A plastic working apparatus, wherein a shearing force is applied to the material a plurality of times at the bent portion. 2. A plurality of barrier bodies are installed on the inner surface of the tubular container flow path, a workpiece is supplied into the tubular container, and the workpiece is brought into contact with the barrier body to form a tubular shape. The plastic working apparatus according to claim 1, wherein an asymmetric work material flow is formed in a cylindrical container cross section in the container, and multiple strains are created in the work material. 3. A multi-stress generated in the step of press-fitting a material to be processed from one end of a cylindrical container having a barrier body installed therein, extruding the material to be processed, and passing through the flow path constituted by the installed barrier body. The plastic working apparatus according to claim 2, wherein multiple strains are created in the work material in the field. 4. The plastic working apparatus according to claim 2, wherein at least one of the plurality of barrier bodies is movable along the inner surface of the tubular container flow path. 5. A pair of plungers is installed on both sides of a work material in a flow path of a tubular container, and a relative work flow between the plunger and the tubular container causes an asymmetric work material flow within a cross section of the tubular container. 2. The method according to claim 2, wherein
The plastic working apparatus as described in any one of 1 above. 6. The plastic working apparatus according to claim 1, wherein a curved portion is formed outside the bent portion. 7. The total inclination angle of a pair of adjacent bent portions is 90 °.
7. The plastic working apparatus according to any one of claims 1 to 6. 8. A workpiece is forcedly circulated through a plastic working apparatus in which a flow path of a cylindrical container having a plurality of bent portions having an inclination angle of less than 90 ° is formed to perform plastic working. A plastic working method characterized in that a shearing force is applied to a work material a plurality of times for each bent portion to generate a strain in the work material.