JP2009090359A - Twist forward extruding device and twist forward extruding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and a method for reducing extruding load by efficiently applying twisting strain in a twist forward extrusion by which the internal structure of a material is fined by applying the large twisting strain to a solid material and powdery material such as metal and high polymer. <P>SOLUTION: In the twist forward extruding device into which the material 1 charged into a cylindrical container 3 is pushed with a pusher 4, one side of the container 3 or a cylindrical die 2 is fixed in the rotational direction so as not to be rotated and the other end is rotated around the axis of extrusion, the die 2 is a two-step die which is composed of an inlet-side die part 2-2 and an outlet-side die part 2-3, a size which completely includes the cross section of the material 1 which is compactly charged in the container 3 and is the non-circular shape-dimension, also the inlet-side cross section of the die hole of the outlet-side die part 2-3 completely includes the outlet-side cross section of the die hole of the inlet-side die part 2-2 and is smaller shape-dimension than the cross section of the material 1 in the container 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a twist forward extrusion apparatus and a twist forward extrusion method. Specifically, in order to produce a material having a fine internal structure, a crystalline structure or an amorphous structure (metal, polymer, wood, etc.) or a material in which an ultrafine second phase is uniformly dispersed, a solid material, The present invention relates to a method of applying a very large working strain to a solid composite material, a powder material, a mixture of different metals, or a mixture of metal and ceramics, hot or cold.

  Usually, a metal material is made into a final product shape by melting and refining the raw material, casting it, and further processing and forming it. There are roughly two types, hot-worked products that are cooled after hot working to produce products, and cold-worked products that are further cold-worked.

  Hot working is processing at an absolute temperature and above the recrystallization temperature and below the melting point. Cold processing refers to processing below the recrystallization temperature. There are many processings at room temperature (20 ° C ± 20 ° C).

  In any of these methods, it is known that the amount of processing applied to the metal material greatly affects the material of the product. Processes such as rolling and casting are particularly effective in reducing the microstructure of crystal grains and the like, and this method is used in many metal materials such as steel materials and aluminum materials. This is because in general, the finer the crystal grains of the metal material, the better the mechanical properties.

  In a hot-worked product, when processed at a high temperature, the metal material becomes a dynamic recrystallization state by increasing the processing strain rate and applying a large strain, and the larger the strain rate, the smaller the crystal grains. When processed at a low temperature (higher than the recrystallization temperature), dislocations accumulate in a cell shape and become fine crystal grains due to rearrangement of the dislocations.

In the cold processed product, the larger the amount of cold processing (recrystallization temperature or less), the smaller the size of recrystallized grains when the subsequent annealing is performed.
The above-mentioned recrystallization behavior is a case where the deformation strain at the time of deformation is small (for example, equivalent strain is less than 1), but recently, a very large processing strain (for example, equivalent strain is 4 or more at an equivalent strain or less). ), It is found that recrystallized grains with few dislocations can be obtained.

  On the other hand, many powder materials have high physical and chemical functions, but in order to use them industrially, they are required to be in a solid state, preferably a relative density close to 100%. ing. For this reason, HIP (Hot Isostatic Pressing) and hot pressing, which can perform consolidation at a temperature higher than room temperature, are frequently used.

  However, in order to achieve higher density, it is necessary to process at a higher temperature. In that case, the properties of the material often change, and a relative density close to 100% is achieved without impairing functionality. There are few examples. In particular, powders that have been refined to a level of 1 micron or less, such as MA (Mechanical Alloying) powders, are extremely difficult to solidify, and it is strongly desired that solidification technology at low temperatures be developed. ing. For this purpose, it is effective to apply a large strain such as a shear strain.

  Furthermore, although it is a kind of MA, when a very large deformation is applied to a bulk metal or a mixture of metal particles of two or more kinds of arbitrary compositions, these are mixed and dissimilar metals are in the order of nanometers. It becomes possible to approach. In the case of mixing metal particles, if processing is continued until the void volume approaches 0, a bulk solid material is obtained, which leads to the production of new alloys (such as ultrafine grain alloys and amorphous alloys).

  Alternatively, it is possible to uniformly disperse the ultrafine grains in the metal by applying a large strain to the mixture of the metal and the ultrafine ceramic grains.

It is also possible to pulverize the precipitates in the metal and disperse them uniformly and finely.
Even in a polymer material, a material having a fine internal structure can be obtained by applying a large twist at a high pressure.

  As described above, the means for applying large strains are the refinement of metal internal structure, non-crystallization, solidification of powder material, mixing of different metals, mixing of metal and ultrafine particles, or microstructure of other substances. Although effective against this, conventional processing means such as rolling, forging, HIP, or hot pressing alone has a limit on the amount of deformation that can be applied (see, for example, Patent Document 1).

  The present inventor has already developed a torsion extrusion method combining extrusion and twisting as a method for achieving a large strain that greatly exceeds the conventional strain (see Patent Documents 1 to 6).

  An example of the method will be described below.

  As shown in FIG. 1, in the forward extrusion method in which the material 1 loaded in the container 3 is pushed by the pusher 4 and formed by the die 2, one of the container 3 and the die 2 is fixed, and the other is This is a torsional forward extrusion method in which extrusion is performed by the pusher 4 while rotating around the extrusion axis a. FIG. 1 shows a case where a die is rotated. The material portion 1-1 is a portion in the container 3 in the material 1, and the material portion 1-2 is a portion that has undergone extrusion molding in the die 2 in the material 1.

When the material portion 1-1 and the material portion 1-2 in the material 1 are relatively rotated, the material in the region A surrounded by the dotted line of the boundary is subjected to torsional deformation. Let D _{m be} the average diameter of the material portion that undergoes this torsional deformation.

In the case of such a torsion extrusion method, when the cavity shape of the die 2 is axisymmetric, a slip occurs between the die 2 and the material 1, and the number of twists of the material 1 may be less than the number of rotations of the die 2. FIG. 2 is a three-dimensional view showing the three-dimensional shape of the die 2 in FIG. When pure aluminum is twisted and extruded using the die 2 having such a shape, slip does not occur, but in the case of a magnesium alloy having many alloy components such as AZ91, slip occurs. When slipping occurs, it is effective to make the shape of the die hole non-axisymmetric as shown in FIG. 3 (see, for example, Non-Patent Document 1 and Patent Document 5). In this case, the cross-sectional shape of the die inlet is circular, and becomes a non-axisymmetric shape such as a square or an ellipse as it approaches the outlet. However, when the shape is gradually changed in this way, the length of the die becomes longer, the extrusion load becomes higher, and the tool life is adversely affected. Incidentally, torsional deformation region of the die is a material part of the range shown in FIG. 3 A, the average diameter of the portion and D _m.

When a change in the cross-sectional shape dimension of the die is abruptly shortened in order to shorten the die length, a material crack often occurs. Therefore, it is important to find a method that can shorten the die length without causing material cracking.
JP-A-2005-000990 JP-A-2005-000991 JP-A-2005-000992 JP-A-2005-000996 JP-A-2005-000993 JP 2005-000994 A Mizunuma, S .: MATER. SCI. FORUM, 503-504 (2006), 185.

  In the twist forward extrusion method, there is a problem in that no material slip occurs, no material cracks occur, and the die length is shortened.

  In order to prevent slippage, it is effective to make a part or all of the cross-sectional shape in the length direction of the die a polygonal shape or an elliptical shape as has been made clear. In order to shorten the die length, it is necessary to change the cross-sectional shape of the die abruptly, but it is effective for preventing cracks to change the cross-sectional shape suddenly at any part in the die length direction. As a result of various studies, it has become clear that it is effective to design a die so that a suddenly deformed portion is formed after material torsion (A region in FIG. 1) occurs.

Specifically, the following three torsional forward extrusion devices do not cause material slip, do not cause material cracking, and can reduce the die length.
The first apparatus pushes the material loaded in the cylindrical container with a pusher, fixes one of the container or the cylindrical die in a rotational direction so as not to rotate, and rotates the other around the extrusion shaft. In the extrusion apparatus, the die is a two-stage die composed of an inlet die portion and an outlet die portion, and the inlet side transverse section of the die hole of the inlet die portion is a transverse section of the material loaded without gaps in the container. , And the shape dimension is not circular, and the entrance side cross section of the die hole of the exit die portion is completely included in the exit side cross section of the die hole of the entrance die portion, And a twist forward extrusion apparatus characterized in that it has a smaller size than the cross section of the material in the container.

  The second device pushes the material loaded in the cylindrical container with a pusher, fixes one of the container or the cylindrical die in a rotational direction so as not to rotate, and rotates the other around the extrusion shaft. In the extrusion apparatus, the die is a two-stage die composed of an inlet die portion and an outlet die portion, and the inlet side transverse section of the die hole of the inlet die portion is a transverse section of the material loaded without gaps in the container. And the entrance side cross section of the die hole of the exit die portion is completely contained in the exit side cross section of the die hole of the entrance die portion, and is in the container. A torsional forward extrusion device characterized by a non-circular shape dimension smaller than the cross-section of the material.

The third device pushes the material loaded in the cylindrical container with a pusher, fixes one of the container or the cylindrical die in a rotational direction so as not to rotate, and rotates the other around the extrusion shaft. In the extrusion apparatus, the container has a fitting recess for fitting with a part of the die, and the die is separated from the container so as to have a space part between the outlet of the container and the inlet of the die hole. And having a plurality of recesses around the die hole on the inlet side end surface of the die, and the inlet side cross section is smaller than the cross section of the material loaded without gaps in the container, A torsional forward extrusion device characterized in that the cross section of the space has a circular shape including the outlet side cross section of the container and the inlet side cross section of the die.
In this third device, the space portion corresponds to the entry die portion of the first and second devices, and the die corresponds to the exit die portion of the first and second devices.
In addition, the cross section of the material loaded in the container without a gap is, in other words, the cross section of the loading hole of the container.

  The dice in the first and second devices may be produced by combining the entrance die portion and the exit die portion separately, or the same effect can be obtained by making them in an integrated shape. In short, it is only necessary to have a two-stage die hole in which the size and shape of the die hole in the entry die portion and the die hole in the exit die portion are different.

  The shape suddenly changing portion in the first to third devices is naturally the boundary between the entrance die portion and the exit die portion. Even in the case of a die having a shape in which the shape suddenly changing portion overlaps the material torsional region, if the material has high ductility, material cracking may not occur. Even if the material is brittle to some extent, if the indentation pressure is very high, material cracking may not occur, but it often causes cracking of tools such as containers and dies.

According to another aspect of the present invention, there is provided a torsional forward extrusion method in which a material is twisted and extruded using any one of the above first to third apparatuses.
In the twist forward extrusion method in which the material is twisted and extruded using the first or second twist forward extrusion device, the material loaded in the container is pushed by the pusher, and the material and the die are relative to each other. Torsional shear strain is imparted to the material portion at the entry die portion, and the material portion to which the torsional shear strain is imparted by the exit die portion from the cross-sectional shape of the material in the container. Are extruded with a small cross-sectional shape.
In the twist forward extrusion method in which a material is twisted and extruded using the third twist forward extrusion device, the material loaded in the container is pushed by the pusher, and the material and the die are relatively rotated. As a result, torsional shear strain is applied to the material portion in the space portion, and the material portion to which the torsional shear strain is applied is pushed out by the die portion with a cross-sectional shape smaller than the cross-sectional shape of the material in the container. Is.

  As described above, by using a die with a combination of an entrance die portion and an exit die portion, even if the die hole shape changes suddenly, material cracking does not occur, and the die length is reduced to the conventional non-axis The length can be less than half of the symmetric die.

Hereinafter, embodiments of the invention will be described with reference to the drawings.
First, the first apparatus and method will be described.

(Embodiment 1)
FIG. 4 is a schematic longitudinal sectional view of Embodiment 1 (first device) of the twist forward extrusion device of the present invention.
The twist forward extrusion apparatus of the first embodiment includes a cylindrical container 3 loaded with a material 1, a cylindrical die 2 disposed adjacent to the container 3, and a material 1 in the container 3 pressed against the die 2. A pusher 4 for rotating the container 3 or the die 2 around the pushing shaft center, and a pressing means (not shown) for moving the pusher 4 in the pushing shaft center direction. 2-2 and the exit die portion 2-3 are two-stage dies, and the entrance side cross section of the die hole of the entrance die portion 2-2 is the cross section of the material 1 loaded in the container 3 without a gap. It is a size that is completely included and has a non-circular shape, and the cross section on the entrance side of the die hole of the exit die portion 2-3 is completely the cross section on the exit side of the die hole of the entrance die portion 2-2. Included in And is smaller geometry than the cross section of the material in the container 3.

As shown in FIG. 4, the die 2 includes an entry-side die portion 2-2 and an exit-side die portion 2-3, and each of the entrance-side die portion 2-2 and the exit-side die portion 2-3 is an axial center portion. Has a die hole.
The entrance side die portion 2-2 includes an entrance wall portion having a die hole, a cylindrical wall portion extending from the outer peripheral edge of the entrance wall portion to the exit side with a constant diameter, and an exit side end portion of the cylinder wall portion in an outer diameter direction. And a protruding outer collar portion.
The exit-side die portion 2-3 includes a body portion having a die hole smaller in diameter than the die hole of the entry-side die portion 2-2, and an outer flange portion projecting in the outer diameter direction from the exit side end portion of the body portion. Have. In addition, in the die hole of the exit side die portion 2-3, the distance H3 portion from the entrance opening end is the narrowest, and the exit side is set slightly larger than that.
This die 2 has a barrel portion of the outlet die portion 2-3 inserted into the cylindrical wall portion of the inlet die portion 2-2, and nuts are passed through holes formed in the overlapping outer flange portions. By tightening with, the entry-side die portion 2-2 and the exit-side die portion 2-3 are integrated so as to be disassembled.
FIGS. 5A and 5B are examples of a three-dimensional view in which the entry-side die portion 2-2 and the exit-side die portion 2-3 are integrated.

6A and 6B are diagrams showing some examples of cross-sectional shapes at respective positions in the length direction of the material. FIG. 6A is a cross-sectional view taken along the line c1-c1 in FIG. 4, and FIG. 4 is a cross-sectional view taken along line c2-c2, and FIG. 6C is a cross-sectional view taken along line c3-c3 in FIG.
FIG. 6A shows a cross section of the material, and a circle or a rectangle is common. FIG. 6B is a cross-sectional view of the entry die portion, which is a quadrilateral or hexagonal cross-section because material torsion occurs in the region A (see FIG. 4) near the contact position between the container and the die. A non-axisymmetric shape such as an ellipse may be used. In short, any shape that does not cause slippage between the outer surface of the material and the inner surface of the die in the entrance die portion may be used. In addition, the minimum dimension D2min of the c2-c2 line cross section must be larger than the maximum dimension D1max of the material cross section. If this dimensional relationship is reversed, material breakage occurs in the torsional region A of the material.

FIG.6 (c) is a figure which shows the cross-sectional shape of a product. Naturally, the maximum dimension D3max of this cross section must be smaller than D2min. The cross-sectional shape is arbitrary, and other than those shown in the figure, for example, an H shape, a rail, and the like are possible, and the degree of freedom of the shape is similar to that of normal forward extrusion. In this case, the average diameter D _m of the torsion region is substantially equal to the material diameter D _0.
The container loading hole and the die hole are formed in the same shape as the cross-sectional shape of the material shown in FIGS. 6 (a) to 6 (c).

  The rotating means includes, for example, a motor that applies a rotational force to the container or the die, a support portion such as a frame, a holder, and a bearing that rotatably holds the container and the die, and the rotational force of the motor to the container or the die. A transmission mechanism such as a plurality of gears or pulleys and belts for transmission, and a motor control unit for controlling the rotational speed of the motor can be provided.

  The pressurizing means includes, for example, a frame erected on a base on which the above-described rotating means, a support portion and the like are mounted, a hydraulic cylinder attached to the frame and having a shaft tip connected to a pusher, and hydraulic pressure applied to the hydraulic cylinder. An expansion / contraction drive unit that supplies and expands and contracts, a hydraulic control unit that controls the expansion / contraction drive unit at a predetermined pushing speed or a predetermined pressure of the pusher, and the like can be provided. When the container side rotates, the shaft tip of the hydraulic cylinder is connected to the pusher via a bearing so that the pusher can also rotate.

  In the case of twisting and extruding a material using the twist forward extrusion apparatus of the first embodiment, the material 1 loaded in the container 3 is pushed by the pusher 4 and the die 2 is rotated with respect to the material 1 to enter the material. The torsional shear strain is imparted to the material portion at the die hole of the die portion 2-2, and the material portion to which the torsional shear strain is imparted by the inlet side of the die hole of the outlet side die portion 2-3 is made the material in the container 3. It is possible to extrude with a cross-sectional shape smaller than the cross-sectional shape.

(Embodiment 2)
FIG. 7 is a schematic longitudinal cross-sectional view in Embodiment 2 (2nd apparatus) of the twist front extrusion apparatus of this invention.
The twist forward extrusion apparatus of the second embodiment has the same configuration as that of the twist forward extrusion apparatus of the first embodiment except that the configuration of the die 2 is different from that of the first embodiment. Hereinafter, points of the second embodiment different from the first embodiment will be mainly described. In FIG. 7, the same reference numerals are given to the same elements as those in the first embodiment.

In the second embodiment, the die 2 is a two-stage die composed of an entry-side die portion 2-2 and an exit-side die portion 2-3, and the entrance-side cross section of the die hole of the entry-side die portion 2-2 is inside the container 3. Is a circular shape that is equal to or completely included in the cross section of the material 1 loaded without gaps, and the entrance side cross section of the die hole of the exit side die portion 2-3 is a die hole of the entrance side die portion 2-2. The non-circular shape dimensions that are completely contained in the outlet side cross section of the material and smaller than the cross section of the material 1 in the container 3.
FIG. 8 is an example of a three-dimensional view in which the entry-side die portion 2-2 and the exit-side die portion 2-3 are integrated.

FIG. 9 is a diagram showing several examples of the cross-sectional shape at each position in the length direction of the material. FIG. 9A is a cross-sectional view taken along line c1-c1 in FIG. 7, and FIG. 7 is a cross-sectional view taken along line c2-c2, and FIG. 9C is a cross-sectional view taken along line c3-c3 in FIG.
The die hole shape of the exit die portion in FIG. 7 is non-axisymmetric such as a quadrangle, a polygon or an ellipse. In the case of FIG. 7, as shown in FIGS. 9A and 9B, the maximum dimension D2max of the entrance die portion is smaller than or the same as the minimum dimension D1min of the material cross section. The cross section of the entry die portion is circular. The shape of the die hole of the exit side die portion 2-3 is non-axisymmetric such as a rectangle or an ellipse. Therefore, the material twist occurs mainly in the region indicated by A in FIG. 7 in the middle of the container in the entrance die portion and the exit die portion. The average diameter D _m of the torsional region is equal to or smaller than the material diameter D ₀ , but if D2max is substantially equal to the material dimension D ₀ , it can be made substantially equal to the material diameter D ₀ in this case as well.

  Also in the case of twisting and extruding a material using the twist forward extrusion apparatus of the second embodiment, the material 1 loaded in the container 3 is pushed by the pusher 4 and the die 2 is pressed against the material 1 as in the first embodiment. The torsional shear strain was applied to the material portion in the die hole of the entry-side die portion 2-2, and the torsional shear strain was imparted by the inlet side of the die hole of the exit-side die portion 2-3. The material portion can be extruded with a cross-sectional shape that is smaller than the cross-sectional shape of the material in the container 3.

(Embodiment 3)
FIG. 10 is a schematic longitudinal cross-sectional view in Embodiment 3 (3rd apparatus) of the twist front extrusion apparatus of this invention.
The twist forward extrusion apparatus of the third embodiment has the same configuration as the twist forward extrusion apparatus of the first and second embodiments except that the configurations of the die 2 and the container 3 are different from those of the first and second embodiments. Hereinafter, differences from the first and second embodiments in the third embodiment will be mainly described. In FIG. 10, the same elements as those in the first and second embodiments are denoted by the same reference numerals.

In the case of the third embodiment, the cylindrical container 3 has a fitting recess that fits with a part of the die 2.
The cylindrical die 2 is made of a single member, and is spaced apart from the container 3 so as to have a space between the outlet of the container 3 and the inlet of the die hole, and at the inlet side end face of the die 2. It has a plurality of recesses (grooves) G around the die hole, and the cross section of the inlet side is smaller than the cross section of the material 1 loaded in the container 3 without any gap.
Further, the cross section of the space portion has a circular shape including the outlet side cross section of the container 3 and the inlet side cross section of the die 2.
In this case, the space corresponds to the die hole portion of the entry-side die portion 2-2 shown in FIGS. 4 and 7, and the die 2 is connected to the exit-side die portion 2-3 shown in FIGS. Equivalent to. Accordingly, the die-shaped sudden change portion is the position of the inlet end face of the die 2. A concave portion G is formed at a position indicated by a dotted line on the inlet end face of the die 2. Since the concave portion G holds the material during the rotation of the die, twisting occurs in the area indicated by A in FIG. 10 and immediately after that, extrusion is performed through the die hole of the die 2. Again, the average diameter D _m of the torsion region is a value close to the material diameter D _0. An example of a three-dimensional view of this die is shown in FIG. FIG. 12 is a view of the entrance end face of the die 2 as seen from the entrance side. The shape of the recess G is arbitrary, but the area is usually 25% or more and 75% or less of the die end face.

The conventional die shown in FIG. 3 is a shape sudden change portion such as a joint portion between the entrance die portion and the exit die portion of the first and second methods (see FIGS. 4 and 7) of the present invention. Alternatively, the third method (see FIG. 10) is designed so that the cross-sectional shape changes gently so as not to create a shape sudden change portion such as the space between the space and the die. This increases the length of the contact area between the inner surface of the die and the material, which increases the extrusion load. In addition, the average diameter D _m of the torsional region A of the material shown in FIG. 3 is considerably smaller than the material diameter D ₀ , and as will be described later, the considerable strain that the material undergoes during torsional extrusion deformation is also considerably reduced. It becomes disadvantageous in terms of conversion.

  In the case of twisting and extruding a material using the twist forward extrusion apparatus of Embodiment 3, the material 1 loaded in the container 3 is pushed by the pusher 4 and the die 2 is rotated with respect to the material 1, thereby The torsional shear strain is applied to the material portion at the portion, and the material portion to which the torsional shear strain is applied can be pushed out by the die 2 portion with a cross-sectional shape smaller than the cross-sectional shape of the material in the container.

  As in the first to third embodiments described above, when a suddenly changing portion having a cross-sectional shape is formed in the die, there is a possibility that material cracks may occur, but if there is no suddenly changing portion in the torsional deformation region A, a certain amount It has been confirmed that there is no material cracking if there is hydrostatic pressure and if there is a certain degree of material ductility. For example, in the case of Mg alloys AZ31, AZ61, AZ91, etc., which have relatively high brittleness, even if the processing temperature is as low as 443K, the condition that this crack does not occur is sufficiently satisfied if the material stretching is 1.5 or more. This is because the torsionally deformed portion and the shape suddenly changing portion do not match.

The equivalent strain in torsional extrusion can be determined from the following equation (1).
Where ε _{Z is} the true strain of axial elongation
ε _T : Cross-sectional average torsional strain due to torsion, and ε _T is expressed by the following equation (2).
here,
D _m is the average diameter of the torsional deformation region of the material.

As shown in the examples below, when D ₀ = 8 mm,
Is normally set to a value between 1 and 10 (1 / mm).
In the case of deformation by this method (first to third methods), the average diameter D _m of the deformation region can be approximately equal to the material diameter D ₀ . Therefore, the equivalent strain is about 10 to 100 from the formula (1). In addition, the equivalent distortion | strain of an axial direction elongation is a quantity about 1-2 among these.
In the case of an appropriate processing temperature, a metal such as aluminum or magnesium alloy is sufficiently ultra-fine with an equivalent strain of about 100. Usually, an equivalent strain of 100 or less is generally used as a guide, but the ultra-fine refinement is saturated at 100 or more. In some cases, the gradual progress may occur as the equivalent strain increases. Therefore, it does not deny giving equivalent strain of 100 or more. In the case of actual operation, the equivalent strain is determined solely by the balance between the degree of demand for ultra-miniaturization and productivity.

  When the conventional non-axisymmetric die as shown in FIG. 3 is used, the equivalent strain is usually about half of this value.

(Example 1)
Using a rod material (diameter 8 mm, length 30 mm) of Mg alloy AZ61 (Al 6%, Zn 1%), twist forward extrusion was performed using the twist forward extrusion apparatus shown in FIG. The twist forward extrusion apparatus shown in FIG. 13 is manufactured based on the first apparatus of FIG. 4 that performs the first method.

  In FIG. 13, reference numeral 2 is a die, 3 is a container, 4 is a pusher, and 1 is a material. Reference numeral 8 denotes a jig for fixing the die 2 and is driven by the motor M and the belt 7. Reference numeral 6 denotes a holder for holding the container 3 and the jig 8 in the space. Reference numeral 9 is a radial bearing, and 10 is a thrust bearing.

  The cross section of the die hole of the entrance die portion 2-2 of the die 2 is 10 mm, and the cross section of the die hole of the exit die portion 2-3 is a circle having a hole diameter of 2.5 mm. The die length is H2 = 1.0 mm and H3 = 4 mm. The set clearance of the contact portion S between the container 3 and the entry die portion 2-2 is 0.1 mm.

  The material was heated to 473 K by a rod heater H built in the container 3. The pushing speed of the pusher 4 is 2 mm / min, and the die rotation speed is 15 rpm.

  FIG. 14 shows an appearance photograph of the molded product that has been twisted and extruded. The thickness of the bite was 0.2 mm. This thickness is larger than the set gap of 0.1 mm, but is due to the backlash of the apparatus and the elastic deformation of the tool. The closed space U formed by the container 3, the holder 6 and the die 2 is manufactured so that there is no gap other than the biting portion S, and further biting occurs when the biting is full. Absent.

  After corrosion of the cross section of the molded product, the structure was observed with an optical microscope. FIG. 15A is a raw material, FIG. 15B is an axial center portion of a molded product, and FIG. 15C is a structural photograph of the outer peripheral portion. The crystal grain size of the material is about 20 to 30 μm, but fine grains of 2 to 3 μm are also observed at the crystal grain boundary. It can be seen that the crystal grain size distribution in the cross section of the molded product is almost uniform, and the majority of the grain size is 1 to 2 μm or less.

  The pusher pushing pressure was about 1100 MPa. In the experiment with a square die (H2 + H3 = 15 mm, molded product □ 3.58 mm) in the type of FIG. 3, the indentation pressure was about 1700 MPa, so the indentation pressure was greatly reduced by improving the die shape. become.

(Example 2)
Using a rod material (diameter 8 mm, length 30 mm) of Mg alloy AZ31 (Al 3%, Zn 1%), torsion extrusion was performed with the torsion extrusion apparatus shown in FIG. The torsion forward extrusion apparatus shown in FIG. 16 is manufactured based on the second apparatus of FIG. 7 that performs the second method. In FIG. 16, the die rotating device is not shown.
A photograph of the dice is shown in FIG. The left is the entry die portion 2-2 and the right is the exit die portion 2-3, which are used in combination. In this case, the diameter of the die hole of the entry-side die portion 2-2 is 8 mm, which is the same as the diameter of the material, and H2 = 4 mm and H3 = 4 mm. The cross section of the die hole of the exit die portion 2-3 is a square of 4 mm.

  Material 1 was heated to 503 K by a rod heater H built in the container 3. The pusher pushing speed is 0.8 mm / min, and the die rotation speed is 4 rpm.

After corroding the cross section of the torsion-extruded molded article, the structure was observed with an optical microscope. The crystal grain size distribution in the cross section was almost uniform, and most of the grain sizes were 3 to 4 μm. The crystal grain size of the material is 20 to 40 μm.
The indentation pressure was about 800 MPa. In the normal method of FIG. 3, it was about 1200 MPa.

(Example 3)
Using a rod material (diameter 8 mm, length 30 mm) of Mg alloy AZ91 (Al 9.2%, Zn 0.7%), torsion extrusion processing was performed with the vertical torsion extrusion processing apparatus shown in FIG. The twist forward extrusion apparatus shown in FIG. 18 is manufactured based on the apparatus shown in FIG. 7 which performs the second method. In FIG. 18, the die rotating device is not shown. The average crystal grain size of the material is about 20 to 30 μm, but fine grains of 1 to 3 μm were also observed at the crystal grain boundary.

  The entrance cross section of the die hole of the entry side die portion 2-2 of the die 2 is circular with a hole diameter of 8 mm, but has a taper of θ = 7.5 ° as shown in FIG. The die hole of the exit side die portion 2-3 is a square of 4 mm. Note that H2 = 4 mm and H3 = 4 mm.

  At the contact position between the container 3 and the entry-side die portion 2-2, there is a circumferential protrusion X (width 3 mm, height 2 mm) on the container side, and a circumferential groove Y (width) on the entry-side die portion 2-2. 5 mm and a depth of 4.9 mm), which are fitted as shown in FIG. The gap between the container 3 and the die 2 must be set larger in S1 than in S2. Moreover, the lubricant was supplied to the circumferential groove Y of the entry-side die part 2-2.

The initial setting value of S2 is 0 mm, and the initial setting value of S1 is 0.1 mm.
Material 1 was heated to 473 K by a rod-shaped heater H built in the container 3. The pusher pushing speed is 1 mm / min, and the die rotation speed is 10 rpm.

  The biting of the test piece after twisting extrusion was about 0.1 mm as installed. In addition, the space U2 was filled with the material, but no biting occurred in the gap S2.

After erosion of the cross section of the torsion-extruded molded article, the structure was observed with an optical microscope. The crystal grain size distribution in the cross section was almost uniform, and most of the grain sizes were 1 to 2 μm or less. .
The indentation pressure was about 1200 MPa. In the normal method of FIG. 3, it was about 1800 MPa.

Example 4
Using a rod material (diameter 8 mm, length 30 mm) of Mg alloy AZ61 (Al 6%, Zn 1%), torsion extrusion was performed with the third torsion extrusion apparatus shown in FIG. 10 as the third method. . The processing temperature is 473K.

  In FIG. 10, reference numeral 1 is a material, 2 is a die, 3 is a container, and 4 is a pusher. A die rotation driving device is not shown.

The cross section of the die hole of the entry side die equivalent portion 2-2 has a hole diameter of 8 mm, and the cross section of the die hole of the exit side die 2 has a circular shape with a hole diameter of 3 mm. The depth of the groove G is 1 mm, a = 5 mm, and b = 8 mm (see FIG. 12). The length H2 = 2 mm (the set gap between the container and the die inlet end face) of the portion corresponding to the entry die is H3 = 4 mm.
The processing temperature is 473 K, the pusher pushing speed is 2.5 mm / min, and the die rotation speed is 15 rpm.

  After erosion of the cross section of the molded product that was twisted and extruded, the structure was observed with an optical microscope. The crystal grain size of the material was about 20-30 μm, the crystal grain size distribution in the cross section of the molded product was almost uniform, and most of the grain size was 3-4 μm.

  The pusher pushing pressure was about 1100 MPa. In the normal method of FIG. 3, it was about 1900 MPa.

It is a principle figure explaining the conventional twisted front extrusion method. It is a three-dimensional view showing an example of an axially symmetric die used in the twist forward extrusion method of FIG. It is a figure which shows the non-axisymmetric die used for the twist front extrusion method, Comprising: Fig.3 (a) is sectional drawing cut | disconnected in the axial direction, FIG.3 (b) is FIG.3 (a) of a1-a6. It is a figure which shows the cross-sectional shape of the material in the die hole of a position. It is a schematic longitudinal cross-sectional view in Embodiment 1 (1st method) of the twist front extrusion apparatus of this invention. FIGS. 5A and 5B are examples of a three-dimensional view in which the entry-side die portion and the exit-side die portion in Embodiment 1 are integrated. FIG. 6A is a cross-sectional view taken along the line c1-c1 of FIG. 4 and FIG. 6B is a cross-sectional view of c2 in FIG. FIG. 6C is a cross-sectional view taken along line -c2, and FIG. 6C is a cross-sectional view taken along line c3-c3 in FIG. It is a schematic longitudinal cross-sectional view in Embodiment 2 (2nd method) of the twist front extrusion apparatus of this invention. FIG. 8 is an example of a three-dimensional view in which an entry-side die portion and an exit-side die portion are integrated in the second embodiment. FIG. 9A is a cross-sectional view taken along the line c1-c1 of FIG. 7 and FIG. 9B is a cross-sectional view of c2 in FIG. FIG. 9 is a cross-sectional view taken along line -c2, and FIG. 9C is a cross-sectional view taken along line c3-c3 in FIG. It is a schematic longitudinal cross-sectional view in Embodiment 3 (3rd method) of the twist front extrusion apparatus of this invention. It is an example of the three-dimensional figure of the dice | dies in Embodiment 3. It is the figure which looked at the entrance end face of the die in Embodiment 3 from the entrance side. It is a schematic longitudinal cross-sectional view of the front extrusion apparatus used in Example 1. 2 is an appearance photograph of a molded product that has been twisted and extruded in Example 1. FIG. FIG. 15A in Example 1 is a material, FIG. 15B is an axial center portion of a molded product, and FIG. 15C is a structural photograph of the outer peripheral portion. It is a schematic longitudinal cross-sectional view of the twist front extrusion apparatus used in Example 2. It is the photograph which decomposed | disassembled the die | dye in Example 2. FIG. It is a schematic longitudinal cross-sectional view of the twist front extrusion apparatus used in Example 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Material 2 Dies 2-2 Entry side die part 2-3 Exit side die part 4 Pusher 3 Container

Claims (5)

In a torsional forward extrusion device that pushes the material loaded in a cylindrical container with a pusher, fixes one of the container or the cylindrical die in a rotational direction so as not to rotate, and rotates the other around an extrusion shaft.
The die is a two-stage die composed of an entrance die portion and an exit die portion, and the entrance side cross section of the die hole of the entrance side die portion completely includes the cross section of the material loaded in the container without gaps. The cross-sectional dimension is a size and a non-circular shape, and the entrance-side cross section of the die hole of the exit-side die portion is completely included in the exit-side cross-section of the die hole of the entrance-side die portion, and inside the container A torsional forward extrusion device characterized in that it has a shape and dimension smaller than the cross section of the material. In a torsional forward extrusion device that pushes the material loaded in a cylindrical container with a pusher, fixes one of the container or the cylindrical die in a rotational direction so as not to rotate, and rotates the other around an extrusion shaft.
The die is a two-stage die comprising an entrance die portion and an exit die portion, and the entrance side cross section of the die hole of the entrance die portion is equal to the cross section of the material loaded in the container without gaps, or A cross-section of the material in the container, wherein the cross-section of the material in the container is a circle that is completely contained, and the cross-section of the inlet side of the die hole of the outlet die portion is completely included in the outlet-side cross section of the die hole of the inlet die portion A torsional forward extrusion device characterized by a smaller non-circular shape. In a torsional forward extrusion device that pushes the material loaded in a cylindrical container with a pusher, fixes one of the container or the cylindrical die in a rotational direction so as not to rotate, and rotates the other around an extrusion shaft.
The container has a fitting recess for fitting with a part of the die,
The die is disposed apart from the container so as to have a space between the outlet of the container and the inlet of the die hole, and has a plurality of recesses around the die hole on the inlet side end surface of the die, And the cross section of the inlet side is smaller than the cross section of the material loaded without gaps in the container,
The torsion forward extrusion apparatus characterized in that the cross section of the space portion has a circular shape including a container outlet side cross section and a die inlet side cross section. A twist forward extrusion method for twisting and extruding a material using the twist forward extrusion apparatus according to claim 1 or 2,
The material loaded in the container is pushed by the pusher, and the material and the die are relatively rotated to impart torsional shear strain to the material portion at the entry-side die portion, and the exit side A torsion forward extrusion method in which a material portion to which the torsional shear strain is applied is extruded by a die portion in a cross-sectional shape smaller than the cross-sectional shape of the material in the container. A twist forward extrusion method for twisting and extruding a material using the twist forward extrusion apparatus according to claim 3,
The material loaded in the container is pushed by the pusher, and the material and the die are relatively rotated to impart torsional shear strain to the material portion in the space portion, and by the die portion, A torsional forward extrusion method in which the material portion to which the torsional shear strain is applied is extruded in a cross-sectional shape smaller than the cross-sectional shape of the material in the container.