UA68674A - Method for plastic structure formation of materials - Google Patents

Abstract

Method for plastic structure formation of materials consisting in single-time or multiple deformation of billet by its extrusion with counterpressure through variable-area channel with conservation of initial form and dimensions of billet after each deformation cycle. The deformation of billet is conducted in the mode of decrease of dimensions of cross section in one direction with simultaneous increase in other cross section. In this case, during extrusion the counterpressure of value not less than the yield point of the work billet is applied to the billet end.

Description

Description of the invention

The invention relates to the field of processing materials by pressure and can be used in the metallurgical, 2 machine-building, aviation and other industries.

Known methods of changing the structure of materials through pressure treatment - methods of plastic structuring |Process! plastic structure formation of metals / Segal V.M., Reznikov V.I.Y.,

Kopyilov V.Y., Pavlyk D.A., Malshev V.F. - Minsk: Science and technology. - 1994. - 232p4. They make it possible to work out the structure of cast metals, to compact powder and porous materials, to form ultra-fine-grained 0 | nanocrystalline structure of metals. Thanks to these changes in the structure, the physical and mechanical properties of these materials are significantly improved.

The development of methods of plastic structure formation is one of the most urgent tasks of metallurgy and materials science |R.Z. Valiev, I.V. Aleksandrov. Nanostructured materials, obtained by intensive plastic deformation - M.: Logos, 2000. - 272 p., pp. 5-13). 19 There are known methods of plastic structuring, which consist in one-time or multiple deformation of the workpiece by squeezing it with back pressure through a channel of constant cross-section while preserving its initial shape and dimensions after each cycle of deformation. These methods include equal-channel angular pressing (RKKP) (patent Российской Федерация Mo21465571 IPC: В 21 С 25/00; AS. USSR Mo804049

MPKO B 21 C 25/00; assistant USSR Mo902962 B 210 25/00) and screw extrusion (GE) | Screw pressing: technological aspect! / I AM. Beigelzimer, D.V. Orlov, S.G. Siinkov, A.V. Reshetov // Physics and technology of high pressures, 2002. - T.12, Mo4. - pp. 40-461).

RKKP consists in the fact that a blank is placed in a vertical channel of a special equipment, consisting of two intersecting channels at an angle (vertical and horizontal) with the same cross-section, which is then pushed through them (patent Российской Федерации Мо21465571 IPC: В 21 С 25/00; AS. USSR 22 Mo804049 IPC: В 21 С 25/00; AS USSR Mo902962 В 21 С 25/00). In the RKKP process, the direction and number of transitions of the workpiece through channels is very important for structure formation. Four to five deformation transitions of the workpiece lead to a decrease in grain size, a rapid increase in the yield strength and strength of the processed material. Then there is a steady stage of strengthening.

Screw extrusion consists in the fact that the prismatic workpiece is passed through a matrix with a screw M 30 channel of constant cross-section. The angle of inclination of the helical line to the direction of the extrusion axis varies with the height of the matrix, and it is zero at its initial and final sections. The specified features of the geometry of the channel lead to the fact that the shape of the workpiece does not change when it is squeezed through it, which allows it to be repeatedly pressed in order to transform the structure and improve the properties of He) metals. This method is described in the article |Vinto pressing: technological aspect! / I AM. Beigelzimer, 325 D.V. Orlov, S.G. Siinkov, A.V. Reshetov // Physics and technology of high pressures, 2002. - T.12, Mo4. - pp. 40-46). at

The main disadvantage of methods of structure formation based on extrusion of the workpiece through channels with a constant cross-section is significant anisotropy of materials after processing, due to the fact that the deformation of metals is carried out by simple shear in narrow centers of intense deformation |(Segal «

V.M., Ganago O.A., Pavlyk D.A. Processing of cast samples by simple shear // Kuznechno-stampovochnoe Z 50 production. 1980. Mo2. P.7-95 Valiev R.Z., Aleksandrov I.V. Nanostructural material), production with intensive plastic deformation - M.: Logos, 2000. - 272 p., pp. 5-13; Screw extrusion is a process

From" the accumulation of deformations. Beigelzimer Y.E., Varyukhin V.N., Orlov D.V., Siinkov S.G. Donetsk: TEAN, 2003. - 85 p.) With RKKP, with high values of strength and plasticity of the metal in the direction of the workpiece axis, very low values of these characteristics are obtained when stretched in the direction at an angle close to 45" to the longitudinal 49 axis of the workpiece. With GE, the material obtains maximum strengthening and simultaneously high plasticity characteristics in the directions that are perpendicular to the axis of deformation, and in the direction of the axis of the blank strength and plastic properties

Ge | significantly lower.

This drawback is eliminated in the methods of plastic structuring, based on the extrusion of metals through channels of variable cross-section. -I 20 The closest to what is claimed is the method of plastic structure formation and the device for its implementation under the name "hourglass" (PG) (A. s. USSR Mo1741960, MKY B 21 in 5/00). Its essence is

That is, the workpiece to be processed is placed in one of two identical receivers of the moving matrix container, symmetrically located with respect to the cylindrical section that calibrates. The blank can be an ingot, a compact made of powdered or granular material, pre-pressed or rolled metal. Then, with one of two identical punches, the material is squeezed through a narrowing channel into the adjacent receiver, and on the other into. punches simultaneously deposit the extruding bar. The first processing cycle ends with the material flowing from one receiver to another. Depending on the processing tasks, the cycle can be repeated n times, i.e. increase the deformation of the workpiece without changing its initial shape and dimensions. After finishing the processing, the blank is removed from the matrix without changing its shape and size, or long-dimensional material is obtained by pressing according to the 60 classic scheme.

The main disadvantage of the prototype method is the significant inhomogeneity of the structure and properties of the material across the cross-section of the workpiece (Greshnov V.M., Golubev O.V., Rtyshchev A.V. New technological scheme of metal pressing // Kuznechno-stampovochnoe proizvodstvo. 1997. Mo2. pp. 8-10Y. Theoretical and experimental studies of metal extrusion processes | Storozhev M.V., Popov E.A. The theory of processing of metals by pressure - M.: Mashinostroenie, 1977. - 423p. convincingly show that the specified drawback is connected with the fact that extrusion of the workpiece is carried out through a narrowing channel.

The task of the present invention is to increase the homogeneity of the structure and properties of the cross-section of the workpiece by improving the method of plastic structuring of materials due to the selection of a certain deformation mode.

The problem is solved by the fact that in the method of plastic structuring of materials, which consists in one-time or multiple deformation of the workpiece by squeezing it with back pressure through a channel of variable cross-section while preserving the initial shape and dimensions of the workpiece after each cycle of deformation, according to the invention, the deformation of the workpiece is carried out in the mode reduction of cross-sectional dimensions in 7/0 one direction while simultaneously increasing in another, and in the process of extruding, back pressure is applied to the front end of the workpiece with an amount not less than the yield point of the workpiece being processed.

Usually, during extrusion, all dimensions of the cross-section of the workpiece are reduced. In the case of expansion extrusion (PE), the dimensions are increased in some directions, hence the name of the process.

Due to the fact that during extrusion, the transverse dimensions of the workpiece decrease in some directions and increase in others, the homogeneity of the deformation distribution across the cross section of the workpiece increases. This leads to homogeneity of the structure and properties across the section. The experimental proof of what has been said is given below in the "example of practical implementation" section.

The essential features listed above make up the essence of the invention in a way, as they are necessary for the implementation of the invention and sufficient to achieve the set task.

Applying to the front end of the blank a back pressure with an amount not less than the yield strength of the deformable material allows you to create a favorable stress state scheme during the processing - a state of comprehensive compression, which is necessary to completely fill the matrix channel with the processed material.

In addition, because the cross-section of the blank repeats the cross-section of the container channel, the blank acquires stability due to the fact that the latter is supported on all sides by the walls of the channel.

During the analysis of the state of the art in patent and scientific and technical sources of information relating to methods for deformation processing of materials, no solution was found that is characterized by features identical to "all essential features of the claimed invention." Therefore, the claimed invention meets the condition of "novelty".

When analyzing the distinguishing features, it was found that the claimed invention does not clearly follow from the known state of the art. For the first time, the pressing of materials through a narrowing-expanding channel with the addition of "E from axial counterpressure" was proposed. The main features are new and not obvious. Thus, the claimed invention meets the condition "inventive level". -

The invention is illustrated by the following graphic materials: Ge

Figure 1 shows a device for deformation processing of materials.

Fig. 2-5 shows the scheme of the matrix for PE. co

Figure b shows successive sections of the channel for expanding extrusion. a and b, respectively, "about the initial and final intersection of the channel.

Fig. 7 shows a photo of the matrix for PE.

Fig. 8 shows the graphs of the distribution of the accumulated strain across the cross-section of the workpiece: after two cycles of PG processing and after one cycle of PE processing (on the larger and smaller sides of the cross-section of the workpiece). "

The device for plastic structuring of materials, shown in Fig. 1, contains: a container 1, in the working section) with a channel (corresponding to the processed workpiece) in which the workpiece 2, punch 3, matrix 4 with sections of the narrowing-expanding channel 5 and calibration 6 are placed (Fig. 2-5). Fig. 2-5 shows matrix 4 for narrowing-expanding;" pressing, which contains three sections: a straight section 7, in cross-section corresponds to the cross-section of the blank 2, which is installed in it before processing; the narrowing-expanding section 5, in which, in fact, deformation of the workpiece of a certain value takes place; straight section 6 of the same cross-section as the input one, but turned relative to the input one

Ge» corner 907.

The essence of the proposed method, which we called expanding extrusion (PE), is explained in Fig. b, which, as an example, shows successive (along the extrusion axis) channel sections for PE (other forms of sections are also possible).

Ge" Fig. 7 shows a photograph of a matrix for expanding extrusion.

With PE, the initial prismatic blank has a cross-section a (this cross-section of the blank is perpendicular to the axis

Sh- extrusions). At the end of the channel, the blank acquires a section b, the shape and dimensions of which coincide with the original. Because the cross-sectional area of the workpiece during PE does not change, it can be repeatedly passed through the matrix, accumulating deformation in order to transform the structure of the materials and improve their physical and mechanical characteristics. 5B The claimed method is implemented in the following way.

The blank 2 through the container 1 is installed with the front end in the straight section of the matrix 7 and, influencing

P» the rear end of the blank is pressed by the punch 3, which is installed, for example, in the power body of the press, through the narrowing-expanding 5 and the output (calibrating) b channels of the matrix 4. A back pressure is applied to the front end of the blank 2 with a value not less than the yield point of the processed material. The workpiece 2, entering the narrowing-expanding channel 5 and being deformed, gradually reduces the linear dimensions of the cross-section in one direction while simultaneously increasing them in the other, accumulating deformation at the same time. Further, the workpiece, exiting into the rectilinear calibrating channel, 6, from the narrowing-expanding channel, gradually acquires its initial shape. When the workpiece 2 completely flows into the direct channel 6 of the matrix 4, pressing is stopped, the punch

C is lifted from container 1, the next blank is placed there and the cycle is repeated. 65 If further processing of the workpiece is necessary, the latter is removed from the output channel, placed again in the input channel and the cycle is repeated the required number of times until the required combination of strength and plasticity.

An example of practical implementation.

A workpiece made of aluminum alloy of the ADI brand in the form of a prism with dimensions of 10x30x80 mm was deformed according to the method described above. The deformed state of the workpiece was studied by the grid method |Smirnov-Alyaev G.A.

Resistance of materials to plastic deformation. L.: Mashinostroenie. 1978. Z68p.|). Studies have shown great uniformity of the accumulated deformation in the blanks, e 7145, fig.8. The distribution of the accumulated deformation in the cross-section of the workpiece after three processing cycles is shown in Fig. 8. As can be seen from the graph in Fig. 8, after two cycles of processing the workpiece AD! by the PG method, a large difference appears between the values of the maximum deformation of the near-contact layers of the workpiece and its central part (GGreshnov V.M., 70 Golubev O.V., Rtyshchev A.V. New technological scheme of metal pressing // Kuznechno-stampovochnoe proizvodstvo. 1997 . Mo2. P.8-10). At the same time, after one cycle of processing blanks from the same alloy by the method

RE, a uniform distribution of the accumulated deformation in the cross-sectional plane of the workpiece is observed, both on the larger and smaller sides of the section.

The given data indicate that the claimed method significantly increases both strength and plastic characteristics of the processed material in all directions of the workpiece and demonstrates the possibilities of industrial implementation of the invention and its unconditional usefulness.

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Claims (1)

The formula of the invention , with. The method of plastic structuring of materials, which consists in one-time or multiple "deformation of the workpiece by squeezing it with counter-pressure through a channel of variable cross-section with preservation of the initial shape and dimensions of the workpiece after each cycle of deformation, which is characterized by the fact that the deformation of the workpiece is carried out in the mode of reducing the dimensions of the cross-section in in one direction with a simultaneous increase in the other, and in the process of extrusion, back pressure is applied to the front end of the workpiece with a value not less than the yield point of the processed workpiece. Official bulletin "Industrial Property". Book 1 "Inventions, useful models, topographies of integrated microcircuits", 2004, M 8, 15.08.2004. State Department of Intellectual Property of the Ministry of Education and 00 zv sciences of Ukraine. with . and? (o) (ee) (o) -and "from" 60 b5