RU2423197C1 - Device for equal-channel angular deformation - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming using intensive plastic deformation and is intended for producing ultra fine-grained and nano-crystalline materials with high mechanical properties. Proposed device comprises male die, female die with moving and stationary parts that form vertical and horizontal channels with their lengthwise axes located at angle to each other. One wall of vertical channel is movable and represents a wedge with taper angle varying from 5° to 8° and width defined from relationship: K=B+N/0.2 Hσ_0.2, where K is vertical movable wall width, B is female die vertical channel width, N is force created by vertical movable wall to mating surfaces of female die vertical surface, H is sum of female die vertical and horizontal channels height, σ_0.2 is yield point of female die and movable vertical wall material. Device comprises appliance to remove vertical tapered movable wall representing vertical extractor and horizontal extractor to generate counter pressure in billet deformation and to extract billet from device.

EFFECT: higher quality and metal utilization factor, reduced process time.

3 cl, 7 dwg

Description

The invention relates to the field of metal forming using intense plastic deformation and is intended to produce ultrafine-grained and nanocrystalline materials with a high level of mechanical properties.

A device for equal channel angular pressing, containing a matrix with a vertical channel and mounted on the base, a punch, a heating element, a movable support that creates back pressure using a hydraulic cylinder. The support forms the geometry of the horizontal channel (1).

The disadvantages of the device is that there are gaps between the matrix and the movable support, leading to a decrease in the quality of the resulting workpieces. In addition, the massive movable support extends from the thermal heating zone during the pressing process, as a result of which it is cooled, requiring additional time for its subsequent heating.

The closest technical solution to the claimed is a device consisting of a punch, a matrix with a movable and fixed parts forming the first and second channels, the longitudinal axes of which are located at an angle to each other, the wall of the first channel in a section of at least B, located opposite the second channel is formed by the fixed part of the matrix, where B is the maximum size of the second channel in height in a section equidistant to the wall, while the movable part of the matrix is installed with the possibility of moving to and from deformation, and the second channel has a cross section of variable length (2).

The disadvantages of this device are: the inevitable ingress of grease from the workpiece into the gaps between the movable and fixed parts of the matrix, as well as parts of the material of the workpiece with any accuracy of fitting the contacting parts of the matrix. In addition, with large efforts to deform the workpieces (1500-2000 kG / cm ² ) due to the elastic deformations of the moving and stationary parts of the matrix, the formation of gaps between them is inevitable.

In addition, with large sizes of deformable workpieces (150 × 150 mm or more), respectively, the sizes and masses of the stationary and moving parts of the matrix increase. In this case, to extract the processed workpiece, it is necessary to extend the matrix parts with increased mass from the deformation zone. In the case of processing workpieces in such an installation in the isothermal mode (and even more so in the superplasticity mode of metals), the removal of part of the matrix from the heating zone entails a drop in the temperature of the device and, as a result, an increase in technological time and additional energy costs for subsequent heating of the device.

The disadvantages of all devices for equal-channel angular pressing (hereinafter RKU) having movable parts, including movable walls, both of vertical and horizontal channels, are the gaps formed in the process of deformation of the workpieces between the contacting surfaces of the channels and movable walls, into which During the deformation process, a part of the workpiece material is pressed in, forming burrs on the latter, making it difficult to move the movable walls to remove the workpiece. This is due to the fact that the relationship between the dimensions of the channels and the reciprocal dimensions of the movable walls is not maintained.

An increase in the clamping force of the moving walls to the counter surfaces of the channels leads to an acceleration of the wear of the wall and matrix surfaces and, as a rule, an increase in the energy consumption for the operation of the device.

The task of the invention is to provide a device for ECG, which allows to improve the quality of the workpieces being processed, as well as to increase the metal utilization rate while reducing the technological time for preparing the workpieces.

The problem is solved using a device for equal channel angular pressing containing a punch, a matrix with movable and fixed parts forming vertical and horizontal channels, the longitudinal axes of which are located at an angle to each other, and the vertical movable wall of the vertical channel is made in the form of a wedge with an angle equal from 5 ° to 8 ° and the width of which is determined from the ratio:

K = B + N / 0.2 H σ _0.2 ,

where K is the width of the vertical movable wall;

B is the width of the vertical channel of the matrix;

N is the force created by the vertical movable wall on the counter surfaces of the vertical channel of the matrix;

H is the sum of the heights of the vertical and horizontal channels of the matrix;

σ _0.2 - yield strength of the matrix material and the movable vertical wall.

The device contains a device for removing a vertical movable wedge-shaped wall in the form of a vertical ejector, and also contains a horizontal ejector made with the possibility of counter-pressure during deformation of the workpiece, as well as removing the latter from the device.

The combination of the above characteristics of the proposed device for equal channel angular pressing can improve the quality of the workpiece, as well as increase the utilization of metal while reducing the technological time for their manufacture. This is confirmed by the fact that in order to prevent the formation of a gap between the side walls of the vertical channel and the side surfaces of the vertical movable wall, the latter, with the width "B" of the vertical channel at the size "H", is made larger by the size "2B" than the width of the vertical channel. At the same time, between the vertical movable wall and the mating surfaces with dimensions “in × H”, it is not enough to create the usual gapless coupling, for example, with one of the transitional landings. Since when deforming, for example, the same aluminum alloys at a temperature of 400 ° C, the specific force of deformation of the workpieces is from 1500 to 2000 kgf / cm ² , which requires pairing on these mating surfaces with interference fit that is comparable to hot pressing fits, which are cyclically repeated movements of the vertical movable wall is possible only with small wedge angles, the tangent of which is comparable with the coefficient of friction between the counter surfaces of the vertical movable wall and the counter surfaces of the matrix. At the same time, surfaces equal to "2c × H" cannot withstand the strength of any load due to possible crushing of these surfaces.

According to (3), σ _cm = (0.1-0.2) σ _t ,

where σ _cm is the allowable stress of the material to collapse;

σ _t - yield strength of the material,

for tool hardened steels σ _t = σ _0.2 ,

whence it can be written that σ _cm = N / 2v × H,

where N is the force created by the vertical movable wall on the counter surfaces of the vertical channel of the matrix.

Transforming the above expressions, we obtain: 0.2 σ _0.2 = N / 2в × Н or в = N / 0.4 σ _0.2 N.

The width of the vertical movable wall is defined as the sum of K = B + 2B, where you can write:

K-B + N / 0.2Hδ _0.2

The operability of the device of the proposed design can only be ensured by fulfilling the above ratios of the listed dimensions of the vertical movable wall in the form of a wedge and a matrix, i.e. creating an optimal interference fit or in another way, elastic stresses between the indicated parts of the device, provided that the wedge angle of the vertical movable wall is α = 5 ° -8 °. At such angles, the tangent of these angles is from 0.09 to 0.14, which corresponds to the friction coefficients of tool hardened steels without surface lubrication with a roughness of 3.2–6.3 μm on the R _a scale. The workpiece after deformation has no burrs, and the vertical movable wall works without jamming and additional readjustments of the matrix parts. As a result, it provides an increase in the quality of workpieces and a reduction in technological time during operation of the installation in serial production.

The movable part of the matrix is much smaller in comparison with the main matrix, which makes it easier to lift it and remove the workpiece more quickly, in addition, the moving part of the matrix does not cool when lifting, as a result of which additional time and energy are not required to heat it up for the subsequent pressing process.

The invention is illustrated by drawings, which shows a device for ECG pressing blanks with a vertical movable wall of the vertical channel of the matrix in the positions:

- before deformation of the workpiece;

- in the process of deformation;

- at the time of removal of the workpiece from the horizontal channel of the matrix and contains the punch 1, the upper movable plate 2, the matrix 3, the vertical channel 4, the horizontal channel 5, the workpiece 6, the horizontal ejector 7, the vertical movable wall 8 in the form of a wedge, the vertical ejector 9.

The figure 1 shows a device for ECG pressing before the deformation of the workpiece, consisting of a punch 1 mounted on the upper movable plate 2. As well as matrix 3 with a vertical channel 4 and a horizontal channel 5.

A blank 6 is installed in the vertical channel 4. A horizontal ejector 7 is placed in the horizontal channel 5. One of the vertical walls of the vertical channel 4 is made movable in the form of a wedge with an angle α, and the angle α has dimensions from 5 ° to 8 °. Under the vertical movable wall 8 in the form of a wedge is a vertical ejector 9.

Size H consists of the sum of the heights of the vertical and horizontal channels.

Figure 2 shows the matrix 3 in cross section AA (see figure 1) with the workpiece 6, a horizontal ejector 7 and a vertical movable wall 8, where the dimensions are indicated:

B is the width of the vertical channel;

c is the distance between the side wall of the vertical channel and the side wall of the vertical movable wall;

K is the width of the vertical movable wall.

Figure 3 shows a device for ECG-pressing in the process of deformation of the workpiece. The punch 1, pushing the workpiece 6 from the vertical channel into the horizontal channel 5, draws due to friction forces the vertical movable wall 8 in the form of a wedge into the counter cavity of the matrix 3, providing a more dense clearance-free fit in this cavity at the point of contact of the surface of the vertical movable wall with the counter walls "in" the vertical channel. At the same time, the workpiece 6, moving along the horizontal channel 5, pushes the horizontal ejector 7 out of the latter. The direction of movement of the punch 1 and the horizontal ejector 7 is shown by arrows.

Figure 4 shows a device for ECG-pressing at the end of deformation by the punch 1 of the workpiece 6.

Figure 5 shows a device for ECG-pressing after removing the punch 1 from the vertical channel 4 of the matrix 3.

Figure 6 shows a device for ECG-pressing at the time of pushing the vertical movable wall 8 in the form of a wedge with a vertical ejector 9 from the cavity of the matrix 3.

7 shows a device for ECG-pressing at the time of removal of the workpiece 6 by a horizontal ejector 7 after returning the vertical ejector 9 to its original position. Arrows indicate the direction of movement of the aforementioned objects of the device.

The device operates as follows.

A vertical movable wall 8 in the form of a wedge is installed in the counter cavity of the matrix 3, after which the workpiece 6 is placed in the vertical channel 4 and, using the plate 2 and the punch 1, the workpiece is deformed in the vertical channel 4 and horizontal channel 5, with the workpiece moving in the horizontal channel 5 s back pressure. Backpressure on the workpiece in the horizontal channel 5 is carried out by acting on it in the opposite direction of movement of the workpiece by means of a horizontal ejector 7. Then, the punch 1 is lifted to its original position, and the ejector 9 lifts the vertical movable wall 8 in the form of a wedge from the cavity of the matrix 3, freeing the exit of the workpiece 6 in the horizontal channel 5. The vertical ejector 9 is returned to its original position and the horizontal ejector 7, the workpiece 6 is removed from the horizontal channel 5.

Then it is possible to repeat the deformation cycle of the next workpiece.

Using the dependencies given in the description of the invention, it is possible to calculate, for example, a vertical movable wall and the response dimensions of the matrix:

for the initial data take the dimensions of the workpiece 150 × 150 × 40 mm, whence, according to the size of the workpiece we have:

vertical channel width - 150 mm

size H = 150 + 40 = 190 mm,

where 40 mm is also the height of the horizontal channel.

To deform the workpiece at a temperature of 400 ° C, the material of the matrix and the vertical movable wall are steel 4X5MFS, which, according to (4), has σ _0.2 = 1270 MPa (127 kG / cm ² ) at a given operating temperature. For calculations, a vertical load is taken to upset a vertical movable wall and create a clamping force P = 6000 kG. The wedge angle of the vertical movable wall α = 6 °, whence, without taking into account the friction forces, it turns out that:

N = P / tg6 ° = 6000 / 0.105 = 57142.8 kG,

according to the data obtained, determine the width - "K" of the vertical movable wall:

K = B + N / 0.2H σ _0.2 = 150 + 57142.8 / 0.2 × 190 × 127 = 162 mm.

Thus, the proposed invention due to the design of the matrix can improve the quality of the workpiece, as well as increase the utilization of metal while reducing technological time for the manufacture of workpieces.

Literature

1. Patent SU No. 6723187, publ. 04/04/2004

2. Patent RU 2146571, publ. 03/20/2000

3. "Reference designer-mechanical engineer", volume 2, ed. V.I. Anurieva, p. 544. - M.: Mechanical Engineering, 1982.

4. "Marochnik of steels and alloys", V. G. Sorokin, A. V. Volosnikova, S. A. Vyatkin., P. 406. - M.: Mechanical Engineering, 1988.

Claims (3)

1. A device for equal channel angular pressing, containing a punch, a matrix with movable and fixed parts forming vertical and horizontal channels, the longitudinal axes of which are located at an angle to each other, characterized in that one wall of the vertical channel is made movable in the form of a wedge with an angle, equal to from 5 to 8 °, and the width determined from the ratio:
K = B + N / 0.2 Nσ _0.2 ,
where K is the width of the vertical movable wall;
B is the width of the vertical channel of the matrix;
N is the force created by the vertical movable wall on the counter surfaces of the vertical channel of the matrix;
H is the sum of the heights of the vertical and horizontal channels of the matrix;
σ _0.2 - yield strength of the matrix material and the movable vertical wall. 2. The device according to claim 1, characterized in that it contains a device for removing a vertical movable wall in the form of a vertical ejector. 3. The device according to claim 1, characterized in that it contains a horizontal ejector made with the possibility of counter pressure during the deformation of the workpiece, as well as removing the latter from the device.

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