JP4992064B2 - Strong processing apparatus and strong processing method - Google Patents

Description

  The present invention relates to a strong working apparatus and a strong working method, and more particularly to a strong working apparatus and a strong working method capable of effectively introducing a high strain to a metal material.

  Conventionally, it has been discovered that the strength and toughness, which have been considered to be in a trade-off relationship in metal materials, can be suitably improved by refining metal crystal grains. In order to improve the characteristics of a metal material, various methods for refining crystal grains of the metal material have been studied. As a method for realizing crystal grain refinement of a metal material, there is a strong strain processing method. The strong strain processing method is to refine crystal grains to a nano size by repeatedly applying a large plastic strain to a metal material. In this regard, Non-Patent Document 1 discloses an Equal Channel Angular Pressing method (ECAP method), which is a representative high strain processing method.

  FIG. 6 is a diagram conceptually showing the ECAP method. As shown in FIG. 6, the ECAP method applies a large shear strain to the metal material 52 at the bent portion 54 by extruding the metal material 52 through a mold 50 having a path bent by 90 °. In the ECAP method, since the diameter of the material does not change by processing, the above process can be repeated any number of times, and a large strain can be applied while the metal material 52 is maintained in a bulk state. However, in the ECAP method, since there is only one direction to give strain, the degree of crystal grain refinement tends to be inhomogeneous, and since it is a discontinuous process, it is a long material. There was a problem that could not be applied. Furthermore, the most serious problem of the ECAP method is that a very large processing force is required to counter the frictional force between the metal material 52 and the wall surface of the path of the mold 50. It was hindering.

In this regard, Non-Patent Document 2 discloses a Severe Torsion Straining Process method (STSP method) that combines heating and torsional deformation. FIG. 7 is a diagram conceptually showing the STSP method. As shown in FIG. 7, in the STSP method, the cooling water 64 is discharged from the vicinity of both ends of the current coil 60 while passing the columnar metal material 62 through the current coil 60, so that At the same time as the local induction heating is performed, the metal material 62 is twisted in the direction of the arrow R in the figure to cause plastic strain in a concentrated manner in the heated portion. By sequentially moving the metal material 62 in the longitudinal direction in this state, plastic strain can be applied over the entire length of the metal material 62. Since this method does not require a mold, the problem of increased machining force due to frictional force is avoided, and since it is a continuous process, a large strain is continuously applied to a long object. In view of this, it showed a certain possibility for industrial practicality. However, the above-described method for refining crystal grains using the heating effect cannot be applied to a material that is easily recrystallized due to the influence of heat.
Segal, V.M. M. Reznikov, V .; I. , Drobyshevsky, A. E. and Kopylov, V.A. I. : Russian Metallurgy, 1, p. 99 (1981) K.Nakamura, K.Neishi, K.Kaneko, M.Nakagakiand Z.Horita: Materials Transactions 45, 12,3338-3342, (2004) "Development of Severe Torsion Straining Process for Rapid Continuous Grain Refinement"

  This invention is made | formed in view of the subject in the said prior art, and this invention is the industrially practical strong processing apparatus and strong processing which can introduce | transduce high distortion with respect to a metal material effectively. It aims to provide a method.

  As a result of studying an industrially practical strong processing apparatus that can effectively introduce a high strain to a metal material, the present inventor has found that a plurality of rolls formed so that the rolling direction of the metal material changes. Cavity rolling is performed using cavities having different opening shapes, and piercing rolling is performed using a plurality of cavities formed so that the opening area is equal to the cross-sectional area of the metal material. Thus, the present inventors have found that a large plastic strain can be uniformly imparted to a metal material while greatly reducing the processing force, and have led to the present invention.

  That is, according to the present invention, a metal material strong processing apparatus includes a perforated rolling roll in which a plurality of perforations are arranged in the roll body length direction, and the plurality of perforations have different opening shapes. And an open area is equal to a cross-sectional area of the metal material. Further, according to the present invention, the apparatus is a strong processing apparatus for a metal material, comprising a plurality of perforated rolling rolls arranged in tandem in the processing axis direction, and a plurality of perforated rolling rolls The hole mold has an opening area equal to the cross-sectional area of the metal material, and the hole molds formed in the adjacent hole rolls have different opening shapes. Is done. The strong processing apparatus of the present invention may further include means for applying a pulling force and / or pushing force in the processing axis direction to the metal material, and the inner wall surface of the hole mold is a rough surface. Can do. Further, according to another configuration of the present invention, there is provided a method of strongly processing a metal material, wherein a plurality of perforations are used to sequentially perforate the metal material using a plurality of perforations having different opening shapes. A method is provided, wherein the plurality of hole types have an opening area equal to a cross-sectional area of the metal material. In the present invention, the plurality of hole molds may be hole molds formed in each of a plurality of hole rolls arranged in tandem in the machining axis direction.

  As described above, according to the present invention, an industrially practical strong processing apparatus and strong processing method capable of effectively introducing high strain to a metal material are provided.

  Hereinafter, the present invention will be described with reference to embodiments shown in the drawings, but the present invention is not limited to the embodiments shown in the drawings.

  FIG. 1 is a front view of a strong processing apparatus 10 of the present embodiment. The strong processing apparatus 10 is configured to include two perforated rolling rolls 12a and 12b. The perforated rolling roll 12a has five recesses 13 to 17 formed on the outer peripheral surface thereof. The roll 12b has five concave portions 18 to 22 formed on the outer peripheral surface thereof. The perforated rolling roll 12a and the perforated rolling roll 12b are positioned with their outer peripheral surfaces being adjacent to each other, and each is configured to be rotatable in the direction of the arrow in the figure with the shaft bodies 24a and 24b as rotational axes. Yes. At the apex where the outer peripheral surface of the punch roll 12a and the outer peripheral surface of the punch roll 12b are in contact with each other, the inner roll wall surface of the recess of the punch roll 12a and the inner wall surface of the recess of the punch roll 12b are used. , 12b, five hole molds 28 to 32 for inserting a metal material in the roll body length direction are formed side by side. In the present embodiment, the hole molds 28 to 32 are configured so that the respective opening shapes are different, and are configured such that the opening areas of all the hole molds are equal to the cross-sectional area of the metal material to be introduced. Yes. In the present embodiment, the cross section refers to a cross section perpendicular to the longitudinal direction (processing axis direction) of the metal material, and the cross sectional area refers to the area. Specifically, a regular octagonal hole mold 32 is formed by the recesses 17 and 22, and an octagonal hole mold 31 flattened by the recesses 16 and 21 is replaced by an octagonal hole mold 30 that is flattened by the recesses 15 and 20. However, the recess 14 and the recess 19 form a square hole mold 29, and the recess 13 and the recess 18 form a regular circular hole mold 28. In addition, although embodiment mentioned above showed the structure where the recessed part of two perforated rolling rolls was provided with the mutually symmetrical shape, and the aperture shape of the perforated form was a line symmetrical shape, the perforated rolling roll in this invention was shown. The aperture shape of the hole type is not limited to the line-symmetric shape, and in view of the strain distribution of the material to be processed, a non-axisymmetric shape can be adopted, and the two hole-type rolling rolls can be mutually Asymmetrically shaped recesses can also be formed.

  FIG. 2 is a perspective view showing a mode in which the metal material 34 is introduced into the hole mold of the strong processing apparatus 10 of the present embodiment. As shown in FIG. 2, when a metal material 34 having a regular circular cross section is introduced into a regular octagonal hole mold 32 formed in the strong processing apparatus 10 from the right side of the paper surface, the metal material 34 is drawn from the tip thereof. It is caught in the perforated rolling rolls 12a and 12b rotating in the direction of the arrow in the figure, and sent out to the left side of the paper while being rolled by the action of the pressure from the perforated rolling roll 12a and the perforated rolling roll 12b. When the metal material 34 is sent to the left side of the paper, it undergoes a complicated three-dimensional deformation due to the pressing action of the perforated rolling roll 12a and the perforated rolling roll 12b. , The cross section is plastically deformed from a regular circle to the same regular octagon as the opening shape of the hole mold 32, and along with this deformation, a shear strain is generated inside the metal material 34. Occurs. In actual processing, it is preferable that the tip of the metal material 34 is substantially tapered in order to smooth the biting at the time of introduction. In the present embodiment, a mechanism for applying a pulling force and / or pushing force in the machining axis direction indicated by the arrow A to the metal material 34 can be provided, and the drawing force and / or pushing force is adjusted. By doing so, processing can be facilitated. In view of the ease of biting by the perforated rolling rolls 12a and 12b, the inner surface of the perforated molds 28 to 32 formed on the perforated rolling rolls 12a and 12b is roughened, for example. It is preferable to appropriately control the friction coefficient of the inner wall surface of ~ 32.

  The metal material 34 having a regular octagonal cross section sent out by the above-described procedure has a strain generated therein as compared with the original material. In the present embodiment, as described above, the opening area of the hole mold 32 is configured to be equal to the area of the regular circular cross section of the metal material 34 to be introduced. The strain in the direction is reduced and most of the pressure is converted into strain in the cross-sectional direction, so that the overall processing force is suitably reduced. Further, since the frictional force at the time of processing in this embodiment is generated only at the tangent line between the inner wall surface of the hole mold 32 and the outer peripheral surface of the metal material 34, the frictional force is generated over the entire inner wall surface of the mold. Compared with the ECAP method, the processing force is remarkably reduced.

  However, when the metal material 34 is rolled at the apex where the outer peripheral surfaces of the perforated rolling rolls 12a and 12b are in contact, the rolling pressure and the rolling rate for the metal material 34 are not uniform in the cross-sectional direction. The strain generated in the pass is not homogeneous. In this regard, in the present embodiment, the strain is made uniform by sequentially introducing and rolling the metal material 34 into a plurality of hole types having the same opening area and different opening shapes. The schedule of the high strain processing will be described with reference to FIGS.

  First, with reference to FIG. 3, a description will be given of a high strain processing schedule for a rod-shaped metal material 34 having a right circular cross section. FIG. 3 shows a top view in each rolling step of the strong working apparatus 10 shown in FIG. 1 in time series in the order of reference numerals (1) to (6). In addition, on the upper side of each top view, The cross section before processing of the metal material 34 is shown below, and the cross section after processing is shown below (the same applies to FIG. 4 below).

  In the first step shown by reference numeral (1), the metal material 34 having a regular circular cross section is introduced into the regular octagonal hole mold 32 in the direction of the arrow in the figure and rolled, whereby the regular octagonal cross section is obtained. The metal material 34 having a surface is delivered. In the second step shown by reference numeral (2), the metal material 34 having a regular octagonal cross section sent out is introduced into the flat octagonal hole mold 31 in the direction of the arrow in the figure and rolled. The metal material 34 having a flat octagonal cross section is delivered. The fed metal material 34 having a flat octagonal cross section is introduced into the flattened octagonal hole mold 30 in the third step shown by reference numeral (3) and rolled in the direction of the arrow in the figure. As a result, the metal material 34 having a flatter octagonal cross section is delivered. The metal material 34 having a flattened octagonal cross section sent out is rotated by 90 ° around the machining axis in the fourth step shown by reference numeral (4), and then flattened octagonal hole type. The metal material 34 having a flat octagonal cross section is sent out by being introduced in the direction of the arrow in FIG. In the fifth step indicated by reference numeral (5), the fed metal material 34 having a flat octagonal cross section is rotated by 90 ° around the machining axis, and then into a regular octagonal hole mold 32. On the other hand, as a result of being introduced and rolled in the direction of the arrow in the figure, the metal material 34 having a regular octagonal cross section is sent out. Finally, the delivered metal material 34 having a regular octagonal cross section is introduced and rolled in the direction indicated by the arrow in the figure with respect to the regular circular hole mold 28 in the sixth step indicated by reference numeral (6). Finally, it is delivered again as a metallic material 34 having a circular cross section. During the first to sixth steps, the cross section of the metal material 34 changes its shape each time, but its area does not change. As described above, in the present embodiment, the metal material 34 fed from the perforated rolling roll 12 is rotated 90 ° or 45 ° around the machining axis in a state where the cross section of the metal material 34 is octagonal. Thereafter, the metal material 34 can be given more uniform strain by repeating the process of being introduced into the perforated rolling roll 12 and rolling again.

  Next, with reference to FIG. 4, a description will be given of a high strain processing schedule for the rod-shaped metal material 35 having a square cross section. In the first step shown by reference numeral (1), the metal material 35 having a square cross section is introduced into the regular octagonal hole mold 32 in the direction of the arrow in the figure and rolled, so that a regular octagonal cross section is obtained. The metal material 35 is delivered. Hereinafter, the second to fifth steps are the same as those described above with reference to FIG. Finally, in the sixth step, the metal material 35 having the regular octagonal cross section sent out in the fifth step is introduced into the square hole mold 29 in the direction of the arrow in the drawing and rolled, and as a result The metal material 35 having the original square cross section is delivered. During the first to sixth steps, the cross section of the metal material 35 changes its shape each time, but its area does not change.

  As described above with reference to FIG. 3 and FIG. 4, in this embodiment, by sequentially introducing the metal material into a plurality of hole types having the same opening area and different opening shapes, Rolling is performed by changing the rolling direction a plurality of times. By this procedure, shear strains in different directions are applied and accumulated in multiple layers with respect to the inside of the metal material, and as a result, large strains are uniformly generated inside while maintaining the shape of the metal material. Moreover, in this embodiment, since a process axial direction does not change in the middle of a processing process, a strong strain process can be suitably performed also to a long metal material.

  In the embodiment shown in FIG. 3 and FIG. 4, the six-step process using five hole molds has been described. However, the present invention limits the hole shape of the hole mold and the number of rolling processes. is not. In the present invention, the aperture shape of the hole shape to be used, the mode of transition of the aperture shape, and the number of steps thereof are high strains in consideration of the deformation characteristics of the material to be processed such as work hardening, crystal system, and texture. It is preferable to optimize so that it can provide uniformly. 3 and 4 show an aspect in which the shape of the cross section before processing of the metal material is equal to the shape of the cross section after final processing. In the present invention, the final shape of the cross section after processing is shown. Can be determined as appropriate, and by making the hole shape opening shape in the final process different from the shape of the cross-section of the metal material before processing, the material shape and the final shape after processing can be made different. .

  The embodiment described above with reference to FIGS. 1 to 4 uses a perforated rolling roll 12 in which a plurality of perforations 28 to 32 are arranged side by side in the width direction, and introduces a metal material intermittently into each perforation. Although a continuous process has been described, according to the present invention, high strain processing can be performed as a continuous process. Hereinafter, with reference to FIG. 5, the process of continuously performing the high strain processing of the present invention will be described. FIG. 5 shows a side view of a strong processing apparatus 40 capable of performing high strain processing as a continuous process. In FIG. 5, the cross section of the metal material 34 before and after processing is surrounded by a broken line. The strong working device 40 is configured to include the perforated rolling rolls 42 to 47, and the six perforated rolling rolls 42 to 47 are arranged in tandem in the working axis direction indicated by the arrows in the drawing. In this embodiment, the hole shape formed in each hole rolling roll is configured to be different from that of the adjacent hole rolling roll. In FIG. 5, the opening shape of the hole type | mold with which each is provided under each hole type rolling roll is shown.

  In the present embodiment, the rod-shaped metal material 34 having a regular circular cross section is first introduced into a perforated rolling roll 42 having a regular octagonal hole mold and rolled, and then a plurality of columns arranged in tandem. It introduce | transduces continuously with respect to the hole-type rolling rolls 43-47. Specifically, the rod-shaped metal material 34 having a regular circular cross section is introduced into a perforated rolling roll 42 including a regular octagonal hole mold 32, and the cross section is rolled into a regular octagon, and then adjacent. It is continuously introduced into a perforated rolling roll 43 having a flat octagonal hole mold 31 and rolled into an octagon with a flat cross section. Next, the rod-shaped metal material 34 having a flat octagonal cross section is continuously introduced into a perforated rolling roll 44 having an adjacent flattened octagonal hole mold 30 so that the cross section is flatter. Rolled into an octagon. Next, the rod-shaped metal material 34 having a flattened octagonal cross section was continuously introduced into the adjacent perforated rolling roll 45 having the flattened octagonal hole mold 31 and the cross section was flattened. It is rolled into an octagon. Here, the perforated rolling roll 45 is a roll having the same perforated mold 31 as the previous perforated rolling roll 43, but in view of the ease of biting of the metal material 34, the perforated rolling roll 44 and the later described. With respect to the perforated rolling roll 46, it is positioned in a state of being rotated by 90 ° around the machining axis indicated by the arrow in the figure. Next, the rod-shaped metal material 34 having a flat octagonal cross section is continuously introduced into a perforated rolling roll 46 having a regular octagonal hole mold 32, and the cross section is rolled into a regular octagon. After that, it is continuously introduced and rolled into a perforated rolling roll 47 having an adjacent round hole 28. As a result, the cross section of the metal material 34 is finally delivered in the original perfect circle. The cross section of the metal material 34 changes its shape each time it passes through the six perforated rolling rolls 42 to 47, but its area does not change. It should be understood that the continuous process described above performs the same processing as the discontinuous process described above with respect to FIG. As described above, according to the present embodiment, it is possible to continuously perform a high strain processing on a long metal material, and the work throughput is significantly improved.

  As described above, according to the present invention, a strong working apparatus and a strong working method capable of effectively introducing a high strain to a metal material are provided. The present invention opens the way to industrialization of high strain processing that can control the internal structure and microstructure of metal materials and improve their properties to the limit, reducing the dependence on resource-constrained alloy elements. It is expected that a new industrial structure will be built.

The front view of a strong processing apparatus. The perspective view which shows the aspect which introduce | transduces a metal material with respect to the hole type | mold of a strong processing apparatus. The figure which shows the schedule which carries out the intense strain process of the rod-shaped metal material which has a perfect circular cross section. The figure which shows the schedule which carries out the intense strain process of the rod-shaped metal material which has a square cross section. The side view of the strong processing apparatus which can perform strong strain processing as a continuous process. The figure which shows ECAP method notionally. The figure which shows the STSP method notionally.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Strong processing apparatus, 12 ... Hole type rolling roll, 13-17 ... Recessed part, 18-22 ... Recessed part, 24 ... Shaft body, 28-32 ... Hole type, 34 ... Metal material, 35 ... Metal material, 40 ... Strong Processing apparatus, 42 to 47: perforated rolling roll, 50 ... mold, 52 ... metal material, 54 ... bent portion, 60 ... current coil, 62 ... metal material, 64 ... cooling water

Claims (6)

A strong processing equipment for metal materials,
It comprises a perforated rolling roll in which a plurality of perforations are arranged in the roll body length direction,
The plurality of hole types have different opening shapes, and the opening area is equal to the cross-sectional area of the metal material,
Strong processing equipment. A strong processing equipment for metal materials,
Provided with a plurality of perforated rolling rolls arranged in tandem in the processing axis direction,
The plurality of perforations formed in the plurality of perforated rolling rolls has an opening area equal to the cross-sectional area of the metal material, and the perforations formed in adjacent perforated rolling rolls have different opening shapes. It is characterized by having
Strong processing equipment.   The strong processing apparatus according to claim 1, further comprising means for applying a drawing force and / or a pushing force in a processing axis direction to the metal material.   The strong processing apparatus according to claim 1, wherein an inner wall surface of the hole mold is a rough surface. A method of strongly processing a metal material,
Including a plurality of perforation rolling steps for perforating and rolling the metal material using a plurality of perforations having different opening shapes;
The method according to claim 1, wherein the plurality of hole types have an opening area equal to a cross-sectional area of the metal material. The method according to claim 5, wherein the plurality of perforations are perforations formed in each of a plurality of perforated rolling rolls arranged in tandem in the machining axis direction.

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