RU2105621C1 - Method for hot extrusion of metal at active action of friction forces and hydraulic extrusion press for performing the same - Google Patents

Method for hot extrusion of metal at active action of friction forces and hydraulic extrusion press for performing the same Download PDF

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RU2105621C1
RU2105621C1 RU93050907A RU93050907A RU2105621C1 RU 2105621 C1 RU2105621 C1 RU 2105621C1 RU 93050907 A RU93050907 A RU 93050907A RU 93050907 A RU93050907 A RU 93050907A RU 2105621 C1 RU2105621 C1 RU 2105621C1
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container
cylinder
press
extrusion
stamp
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RU93050907A
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Russian (ru)
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RU93050907A (en
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Валерий Николаевич Щерба
Владимир Николаевич Данилин
Владимир Сергеевич Разумкин
Владимир Николаевич Алферов
Александр Кузьмич Свинарев
Original Assignee
Валерий Николаевич Щерба
Владимир Николаевич Данилин
Владимир Сергеевич Разумкин
Владимир Николаевич Алферов
Александр Кузьмич Свинарев
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Priority to RU93050907A priority Critical patent/RU2105621C1/en
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21CMANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C23/00Extruding metal; Impact extrusion
    • B21C23/21Presses specially adapted for extruding metal
    • B21C23/211Press driving devices
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21CMANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C23/00Extruding metal; Impact extrusion
    • B21C23/21Presses specially adapted for extruding metal
    • B21C23/218Indirect extrusion presses
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21CMANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C31/00Control devices, e.g. for regulating the pressing speed or temperature of metal; Measuring devices, e.g. for temperature of metal, combined with or specially adapted for use in connection with extrusion presses

Abstract

FIELD: plastic metal working, namely hot extrusion of metal at active action of friction forces for manufacturing rods and shapes. SUBSTANCE: method comprises steps of placing blank in container and extruding it through die for receiving necessary shape and dimensions of product. Extrusion is realized by means of extrusion ram at simultaneously moving container and said ram. Motion speed of container is more than that of extrusion ram. Motion speed of container is set according to extrusion rate and temperature range of blank. Ratio of motion speed values of container and ram is in range 1.05-1.03. Hydraulic extrusion press includes front and rear cross beams rigidly secured to press frame. Main power cylinder and cylinders for moving container connected with high and low pressure circuits are mounted on rear cross beam. Traverse bar is secured to rear cross beam. Traverse bar supports additional cylinder, whose plunger carries extrusion ram. Extrusion ram, container and hollow cylinder are mounted coaxially with possibility of reciprocation motion along lengthwise axis. Hollow extrusion ram is secured to front cross beam of frame. Additional cylinder and cylinders for moving container are hydraulically connected with throttling device being in the form of at least one stabilizing cylinder. Stabilizing cylinder includes cylindrical body in which plunger is arranged. One of stabilizing members of said cylinder is secured to rear cross beam, another is rigidly connected with traverse bar. Inner cavity of stabilizing cylinder is connected with inner cavity of additional cylinder. EFFECT: enhanced efficiency of method, improved design of press. 25 cl, 4 dwg, 1 tbl

Description

 The invention relates to the processing of metals by pressure, and in particular to a method of hot extrusion of a metal with the active action of friction forces and an installation for its implementation, and can be used to obtain rods and profiles that are used in aircraft, construction, automotive, etc.

 The usual known method of hot extrusion of metal includes the following operations: heating the ingot in the furnace, feeding it into the container and extruding the ingot through the die channel with the simultaneous movement of the stamp and the container. The resulting product is transported to a cooling table, and the remaining press residue is separated from the matrix and placed in waste.

 A known method of pressing metal and alloys, including heating a metal billet, placing it in a container, extruding it and removing the product and press residue (see patent N 2675125).

 During the extrusion process, the container and the stamp are mixed with various combinations of their mutual speed, but excluding the excess speed of the container over the speed of the stamp.

 In this method, in one extreme case, the container is stationary, and only the press stamp is mixed, squeezing the ingot through the matrix channel. In this case, a method called direct is implemented, and the resulting products have a high-quality surface.

 At the same time, in the direct method, the workpiece is mixed relative to the container, therefore, reactive friction forces are formed on the contact surfaces of the ingot, directed in the opposite direction from the direction of metal flow. This circumstance requires the application of significant energy costs to overcome them. In addition, the nature of the metal flow in the direct extrusion process is characterized by great non-uniformity, which may cause internal product defects. In another extreme case, according to the specified method, the container and the stamp are simultaneously mixed at the same speeds. This method is called the reverse. In this case, there is no need to overcome the frictional forces between the container and the workpiece; therefore, this process requires significantly less energy costs. The resulting products have no internal defects, but for extrusion requires ingots with a turned outer surface, which requires large additional economic costs.

 With the reverse extrusion method, the uneven flow of the metal remains, although it decreases compared to the direct extrusion method. Unevenness in the metal flow leads to heterogeneity of the structure and physico-mechanical properties, along the length and cross section of the products.

 In addition, the described pressing method is characterized by the presence of a significant velocity gradient in the deformation zone, which limits the limiting flow rates during pressing of a number of alloys. For the same reason, significant tensile stresses arise in the matrix channel on the surface of the products, which can lead to cracking.

 The specified extrusion method provides that part of the process can be conducted in one way, and the other part of the process in another way. In addition, the speed of movement of the container may be slightly lower than the speed of movement of the press stamp. However, each implemented method, respectively, is inherent in those indicated disadvantages to which method it is closer to.

 A device is known (see US Pat. No. 2,675,125), which allows the metal to be extruded by direct, reverse, or mixed methods (during extrusion, one method changes to another).

 The device comprises a container mounted on the bed with the possibility of reciprocating movement along its longitudinal axis and a beam with a plunger of the main cylinder rigidly mounted on it, fixedly mounted on the rear cross member. Two cylinders for moving the container are installed on the traverse, the plungers of which are rigidly fixed to the container. On the front cross-member, reture (return) cylinders for moving the container are installed, the plungers of which are also rigidly fixed to the container. A press stamp is rigidly fixed to the traverse, which enters the container during the extrusion process, and on the other side of the container, a hollow stamp is fixed coaxially with it, fixedly mounted on the front cross member.

 The internal cavities of the hydraulic power cylinders are connected through a junction box to the high and low pressure lines.

 The heated billet feed device is raised on the axis of the press. Idle traverse her push into the container. Then begin (for example) the pressing process by direct method. The container return cylinders are closed, and the high-pressure liquid is supplied to the master cylinder, and the container cylinder is connected to the low-pressure line. Under the influence of the press stamp, the workpiece begins to be squeezed out through the die. After reaching the specified value of the workpiece, the press is transferred to the reverse method. For this, the container’s cylinder cylinders are connected to the low-pressure line, and the container cylinders are closed. At this point, the speed of the pressing beam and the container are leveled, the reverse method of pressing begins. After reaching the set value of the press balance, the process is stopped, the Press balance is removed from the container by the cylinders for moving the container and separated. The product is removed and the cycle can be repeated.

 If necessary, the press can be extruded only by direct or reverse methods. Other combinations are also possible along the way.

 The use of such a device allows extruding on one installation, depending on the need, either by direct or reverse methods, while using the advantages characteristic of a particular method.

 At the same time, the use of such a device is very difficult, since it requires coordination of the movements of two hydraulic systems simultaneously, one serving to move the container, the other directly to extrude the metal through the matrix. During the pressing process, efforts to overcome the reactive friction forces on the side surface between the workpiece and the container are significantly reduced due to the reduction in the length of the workpiece. This leads to a change in several times the required effort to move the container. Such working conditions require special expensive regulating devices for supplying the working fluid to the working force cylinders.

 In addition, since the container moving cylinders and container container cylinders must be locked, they are responsible for all the press force. This leads to a significant increase in pressure in them (animation), and, consequently, to rapid wear of the seals and frequent repair of the press.

 In addition, this device does not allow extruding with the active action of friction. Therefore, products are obtained with a low level of mechanical properties and their uneven distribution along the length and cross section of the products. At this installation, the maximum flow rates of the metal cannot be reached, which reduces the productivity of the process.

There is another method of hot extrusion with the active action of friction forces, which consists in the following. The ingot intended for extrusion is heated, placed in a container and then squeezed out by joint movement of the press stamp and the container through the matrix channel, which determines the shape of the product. During the extrusion process, the container is mixed at a speed greater than the speed of movement of the press stamp, and the speed V from the movement of the container (3) is set depending on the speed of extrusion (see SU, A.S. N 645721, class B 21 C 23/08 )

Heating the workpiece before pressing allows you to reduce the resistance to deformation of the material and thereby reduce the required effort to carry out the process. For extrusion, the ingot must be placed in the container and closed on one side with a matrix with a channel corresponding to the profile of the product obtained, and on the other hand with a short stamp. The die is mounted on the hollow die, after which the container and the die are mixed, the speed of the container is greater than the speed of the die, and the speed V from the movement of the container is set depending on the speed of extrusion. As a result of such movement at the boundary between the container and the workpiece, the reactive friction forces characteristic of the direct process are converted into active friction forces directed towards the outflow direction and contributing to it.

 This direction of the friction forces makes it possible to somewhat equalize the metal flow velocity in the matrix channel, which makes it possible to obtain better products.

 It was experimentally established that the effectiveness of this process largely depends on the conditions of interaction of the container with the workpiece, i.e. on the degree of realization of the friction forces of an active action. Therefore, during extrusion, when the speed of the container is significantly higher than the speed of the stamp, an excessive shift of the container relative to the workpiece is observed. This circumstance causes an intensive flow of the peripheral layers of the workpiece, which is accompanied by their heating, and this in turn affects the conditions for the removal of heat generated from the crimp zone of the plastically deformable metal. In addition, an increase in the temperature of the peripheral layers of the metal of the workpiece leads to the localization of shear deformation over the cross section of the workpiece and thereby limits the volumetric pressing effect in the mode of using the active action of friction forces. This leads to a decrease in the permissible pressing speed and a deterioration in product quality.

 In addition, the choice of a larger ratio of the speed of movement of the container to the speed of movement of the press stamp requires either a decrease in the initial length of the ingot, which leads to a decrease in the productivity of the machine, or an increase in the length of the container, which leads to a complication and a significant increase in the cost of the press.

 The use of a kinematic coefficient below the optimal values during extrusion leads to the localization of shear deformation in the boundary layer, which increases the unevenness of the metal flow and reduces the allowable level of pressing speed.

 A known installation for extruding metal using the active action of friction forces (see SU, a.s. N 645852, class B 30 B 15/26, 1979).

 A hydraulic extrusion press comprising a front cross member and a rear cross member rigidly fixed to the bed with a main power cylinder and container moving cylinders fixedly connected thereto, communicating with high and low pressure lines, a throttling device connecting the high pressure line with container moving cylinders, installed with the possibility of reciprocating movement along the longitudinal axis of the bed and coaxially arranged press stamp associated with the plunger m main power cylinder, container and the hollow ram mounted on the front cross member. In the initial position, the plunger of the additional cylinder is extended as far as possible from the cylinder.

 The heated billet is fed to the axis of the press and is pushed into the container with the die using a hollow press stamp. High pressure fluid is fed into the master cylinder and the crosshead together with the container is lowered down. Begin the stage of extrusion, and then extrusion. At this moment, the speed of the container and the stamp are the same, the reverse extrusion process takes place. After the outflow of metal begins, the throttle is opened and the liquid from the additional cylinder begins to overflow into the low-pressure line. The plunger of the additional cylinder is heated, which leads to a decrease in the speed of movement of the press stamp relative to the speed of movement of the container. The friction forces of the active action are induced on the side surface of the workpiece.

 After reaching the set value of the press residue, the extrusion process is stopped. The high pressure liquid is fed into the retour cylinders and the crosshead returns to its original position.

 The press residue is separated from the product and removed. The die is mounted on the hollow die and the cycle can be repeated.

 This press allows you to carry out the process using the active action of the friction forces.

 At the same time, in order to achieve high press performance and obtain a high level of mechanical properties of products, it is necessary to strictly maintain the speed of movement of the container and the speed of movement of the press stamp in a certain optimal ratio during the pressing process. This press does not allow you to accurately maintain this ratio. The regulation of the speed of movement of the container relative to the stamp is carried out by releasing the liquid from the additional cylinder through the throttle to the low pressure line. In the process of pressing, as mentioned above, the force required to move the container changes several times. This leads to the same pressure changes in the additional cylinder. Therefore, opening the throttle to the same amount at different stages of the process leads to different amounts of fluid release, and therefore, to obtain different ratios of the speeds of movement of the containers of the stamp. In this press, it is impossible to take into account the changing process conditions; during the extrusion of the metal, it is necessary to open or close the throttle. Deviation of the ratio of the speeds of movement of the container and the press die from the optimum requires a significant reduction in the speed of extrusion, the products are obtained with defects and uneven distribution of mechanical properties along the length.

The objective of the invention is the creation of such a method of hot extrusion of metal with the active action of friction forces and a hydraulic extrusion press for its implementation, which would be due to a certain ratio of the speeds of movement of the container and the stamp would increase the productivity of the process and at the same time regulate the distribution of the mechanical properties of the resulting product along its length . This problem is solved in that in a method of hot extrusion of metal with the active action of friction forces, including heating the workpiece to be extruded (1), placing it in a container (3) and extruding through a matrix (5) that determines the shape and geometric dimensions of the finished product, s using a stamp (4) while moving the container and the stamp with a speed of movement of the container at a higher speed of movement of the stamp (4), and the speed V from moving the container (3) is set depending on the speed according to the invention, the speed V from the movement of the container (3) is set depending on the speed of extrusion or on the temperature field of the workpiece (1), the ratio of the speeds of movement of the container (3) and the stamp (4) during the extrusion process is maintained in the range of 1, 05-1.3, and the greater the value of the extrusion speed corresponds to a larger value of the ratio of the speeds of movement of the container and the stamp.

 This allows you to increase the productivity of the process, increase the level of mechanical properties, simplify the design of the press, provides uniform mechanical properties along the entire length of the products and makes it possible to obtain products with a regulated distribution of mechanical properties.

 During the extrusion process, the ratio of the speeds of the container and the stamp can be kept constant. This simplifies the design of the press. During the extrusion process, the ratio of the speeds of the container and the stamp can be changed in the range from 1.05 to 1.3 times.

 This makes it possible to obtain products with a regulated distribution of mechanical properties.

 The ratio of the heating temperature of the front end of the workpiece to the heating temperature of the rear end of the workpiece is 1.8-1.1. This makes it possible to further increase the productivity of the process.

During the extrusion process, the speed V R of the movement of the stamp is changed depending on the change in the temperature gradient of the workpiece along its length. This allows you to regulate the mechanical properties of the resulting product along its entire length.

 The same problem is also solved by the fact that in a hydraulic extrusion press containing a front cross member and a rear cross member rigidly fixed to the bed with a main power cylinder and container moving cylinders fixedly connected thereto, communicating with the high and low pressure lines, a throttling device connecting the high line pressure with container movement cylinders installed with the possibility of reciprocating movement along the longitudinal axis of the bed and located the press stamp associated with the plunger of the master ram cylinder, the container and the hollow press stamp fixed on the front cross member according to the invention, the cross member is rigidly fixed to the plunger of the master cylinder, on which the additional cylinder is mounted, on the plunger of which the press stamp, the additional cylinder hydraulically connected with a throttling device made in the form of at least one stabilizing cylinder, consisting of a cylindrical body with a plunger placed in it, and one of these elements of the stabilizing cylinder is mounted on the rear cross member, and the other is rigidly connected to the traverse, while the inner cavity of the stabilizing cylinder is in communication with the inner cavity of the additional cylinder.

This ensures that the optimum ratio V C / V R of the speeds of movement of the container and the press stamp during the extrusion process is automatically obtained, which makes it possible to obtain an exact alignment of the press stamp, and thereby improve product quality.

 The inner cavity of the stabilizing cylinder may communicate with the low pressure line. This allows the traverse to idle.

For a given value of the ratio of the speeds of the container and the stamp, the cross-sectional area of the stabilizing cylinder is
F s -F a (1-1 / K W ),
Where
F S is the cross-sectional area of the stabilizing cylinder;
F a is the cross-sectional area of the additional cylinder;
K W - the ratio of V C / V R speeds of the container V C and the stamp V R ;
and the length of the inner working cavity of the additional cylinder is
H a = H w b (1-1 / K w )
Where
H a the length of the working cavity of the additional cylinder;
H w b - the maximum length of the stroke of the stabilization cylinder.

 This allows you to get the required ratio of the speeds of the container and the stamp.

 It is advisable that the hydraulic extrusion press contains at least two forcing force cylinders, each of which is made in the form of a cylindrical body with a plunger located in it and one of these elements of each forcing force cylinder is fixedly mounted on one of the cross-beams, and the other on the traverse, and the internal cavity of each of them is connected to the low and high pressure line.2 This saves high pressure liquid.

 The hydraulic connection of the inner cavity of each cylinder, hydraulically connected to the additional cylinder, with the corresponding high and low pressure line, can be carried out through the valve.

 This simplifies overall press management.

 It is advisable that the internal cavity of each forcing cylinder is hydraulically communicated with the internal cavity of the additional cylinder. This makes it possible to expand the technological capabilities of the press.

 The hydraulic connection between the inner cavity of the auxiliary cylinder and the inner cavity of each associated hydraulic power cylinder can be through a valve. This eliminates the ingress of air into the hydraulic system.

 The hydraulic extrusion press may contain an additional throttling device, made in the form of a housing with holes and a cover, inside of which a spring-loaded spool with a through cavity is installed, the geometrical dimensions and configuration of which determine the rate of mutual movement of the container and the stamp, the through cavity is hydraulically communicated through the corresponding hole in the housing of the additional throttling device with the internal cavity of the additional cylinder pa and manifold the low pressure side of the spool opposite the spring-loaded side spool mounted cylinder body which is rigidly connected to the housing of the auxiliary restricting unit, while a plunger is rigidly connected to the spindle, the inner cavity of this cylinder is hydraulically communicated with the inner space of the auxiliary cylinder.

 This allows you to get a variable ratio of the speeds of the container and the stamp during the process.

 The cover of the additional throttling device is installed with the possibility of axial movement to control the amount of preliminary preload of the spool spring. This makes it possible to expand the technological capabilities of the throttling device.

 In addition, an additional throttling device can be equipped with a lead screw fixedly mounted on the end of the spool from the spring side, and a through hole is made in the cover, in which the screw is placed with the possibility of controlling their reciprocating movement. This makes it possible to expand the technological capabilities of the throttling device.

 It is advisable to install a valve between the additional cylinder and the additional throttling device. This allows you to expand the technological capabilities of the press.

 The cylindrical body and, accordingly, the plunger of the additional cylinder can be made stepwise, and the cavities formed by these steps are hydraulically interconnected. This reduces the overall size of the press.

 Rationally, the stage of the additional cylinder facing the plunger of the main power cylinder is partially placed in this plunger and rigidly connected to it. This allows you to further reduce the size of the press.

 In FIG. 1. schematically shows a hydraulic extrusion press for implementing the method of hot extrusion of metal with the active action of friction, according to the invention; in FIG. 2. schematically one of the optimal embodiments of a hydraulic extrusion press according to the invention; in FIG. 3. schematically an additional throttling device according to the invention; in FIG. 4. schematically, an embodiment of a hydraulic extrusion press with a stepped plunger of an additional cylinder according to the invention.

 A patented method of hot extrusion with the active action of friction forces is as follows.

 The blank 1 (Fig. 1, 2, 4) to be extruded is heated, it is placed in the cavity 2 of the container 3 and then, by moving the press stamp 4 and the container 3 together, it is squeezed out through the channel of the matrix 5, which determines the shape of the finished product (in FIG. not shown), which is mounted on the hollow die 6. In the extrusion process, the container 3 is mixed at a speed exceeding the speed of the press die 4 by about 1.05-1.3 times.

The heating of the workpiece 1 can be carried out, for example, in induction furnaces, resistance furnaces, and flame heating furnaces (not shown in FIG.). The heating temperature range of the preform 1 is selected depending on the type of alloy of the preform 1 to be extruded. For example, in the case of heating preforms 1 of hardly deformable aluminum alloys, heating is carried out to a temperature of about 300-400 o C depending on the requirements for the mechanical properties of the products and the speed of pressing.

 Heating the workpiece before extrusion reduces the resistance to deformation of the workpiece material to be deformed. This reduces the energy consumption for the completion of the extrusion process. In addition, in a number of alloys, for example, in the case of processing difficultly deformed aluminum alloys, heating of the workpieces makes it possible to increase the level of mechanical properties in the products. In addition, in some cases, heating allows to increase the adhesive interaction between the workpiece 1 and the container 3, which leads to an increase in the friction forces, and this is very important for the patented process, since in the considered method the friction forces between the container 3 and the workpiece 1 play a positive role, increasing the depth peripheral flow to metals. So, their increase contributes to the alignment of the flow velocity of the metal in the channel of the matrix 5. This allows you to increase the limiting velocity of the flow of metal. After heating, the workpiece using the feed mechanism 7 is fed to the press and pushed into the cavity 2 of the container 3 of the press. The length of the container 3 is performed in such a way that the whole preform, die 5 and press stamp 4 can freely fit in it. The length of the press stamp 4 is consistent with that part of the length of the container 3 that is necessary for mutual mixing relative to the workpiece.

To reduce the energy costs of the extrusion process before pressing, the container 3, the die 5 and the stamp 4 can be preheated. The heating temperature depends on the material of the extrudable billet 1. For example, when pressing hardly deformable aluminum alloys, it is approximately 300-400 o C.

 Then, in the course of the traverse 8, they simultaneously begin to mix the container 3 and the press stamp 4 towards the matrix 5. Moreover, the length of the hollow press stamp 6 should be equal to the length of the container 3 so that the matrix 5 can be removed from the opposite side of the container 3.

 After the stamp 4, the workpiece 1 and the die 5 come into contact, the stage of unpressing the workpiece 1 begins. At this stage, the workpiece 1 occupies the entire volume limiting it. The diameter of the workpiece 1 becomes equal to the diameter of the container 3. After that, the metal begins to be extruded into the matrix channel 3. The channel configuration of the matrix 5 corresponds to the cross section of the obtained product, but taking into account the thermal expansion of the matrix 5 as a result of its heating and some shrinkage of the metal after it is cooled. During the stage of extrusion, the speed of movement of the container 3 and the stamp 4 must be the same (reverse pressing method), otherwise, separate parts of the side surface of the workpiece 1 can be shifted to another part of this surface, since only part of the workpiece 1 is in contact with the container 3 This may result in defects in the products.

After the beginning of the pressing stage, the speed V C of the movement of the container 3 is increased 1.05-1.3 times compared with the speed V R of the movement of the stamp 4. The ratio of the speed V C of the movement of the container 3 to the speed V R of the movement of the stamp 4 is called kinematic coefficient K W.

 As a result of this mutual displacement, friction forces appear on the side surface of the workpiece 1, which are directed toward the outflow of the metal, which makes it possible to create an accelerated peripheral metal flow in the workpiece 1 and slow down the axial layers. This significantly changes the nature of the metal flow, which leads to a smoothing of the metal flow in the compressive part of the plastic zone, and therefore in the channel of the matrix 5. A more uniform metal flow provides a reduction in tensile stresses on the side surface of the finished product. These stresses are the main constraining factor in the choice of the limiting extrusion rate on a whole series of alloys, for example, during the extrusion of hardly deformed aluminum alloys. Thus, a decrease in tensile stresses makes it possible to increase the maximum permissible extrusion rates during deformation of difficultly deformed aluminum alloys by 2–3 times. In addition, such a favorable metal flow creates conditions for a quasi-steady flow of metal, which reduces the uneven distribution of mechanical properties along the length and cross section of the products.

During extrusion under the conditions of the active action of friction forces, the workpiece material undergoes additionally not only shear deformations, but also inhibition of the axial flow, and this contributes to a better study of the cast structure of the material and an increase in the density of dislocations, which makes it possible to increase the general level of mechanical properties in the products. For example, when extruding hardly deformed aluminum alloys, all other things being equal, an increase in the mechanical properties of products is 10–40%
At the same time, the effectiveness of this process substantially depends on the conditions of interaction of the container 3 with the workpiece 1, i.e. the magnitude of the implementation of the active action of friction forces.

It has been experimentally established that in the case of extrusion, when the ratio of the speeds V C / V R of the container and the stamp exceeds 1.3, an excessive shift of the container 3 relative to the workpiece 1 is observed. This circumstance causes an accelerated flow of the peripheral layers of the metal, which in turn leads to increased heating of these layers and leads to deterioration of heat removal from the crimping part of the plastic zone of the workpiece 1. This requires a decrease in the pressing speed. In addition, an increase in the temperature of the peripheral layers of the metal leads to a decrease in the deformation resistance, and this in turn leads to the localization of shear deformation over the cross section of the workpiece and thereby limits the volumetric pressing effect in the mode of using the active action of the friction forces. This makes it necessary to reduce the pressing speed.

In addition, the choice of an excessively large ratio V C / V R of the speed V C of the movement of the container 3 to the speed V R of the movement of the stamp 4 (more than 1.3) requires either a reduction in the initial length of the workpiece 1, which naturally leads to a decrease in the productivity of the press, or increasing the length of the container 3, which increases the metal consumption of the press structure and, consequently, leads to its cost increase.

Using during the extrusion process the ratio of the speeds V C / V R of the container 3 and the press stamp 4 below the optimal values K W <1.05 leads to the localization of shear deformation only in the boundary layer of the workpiece 1, which reduces the volumetric effect of the friction forces. This leads to uneven flow of the metal and reduces the permissible level of extrusion speed, leads to a deterioration in the quality of products.

 The extrusion process is carried out to a certain size of the workpiece 1, called a press residue (not shown in FIG.). The height of the press residue is mainly determined by the moment the formation of the press weights of the first kind begins.

 In the case of pressing with the active action of friction forces at the end face of the workpiece facing the short press stamp 4, friction forces converging to the axis of the ingot are induced. This nature of the action of the friction forces allows you to significantly delay the start of the formation of a press-type of the first kind, which allows deformation to a smaller value of the press residue. For example, when pressing hardly deformable aluminum alloys, this height is 0.05-0.1 of the diameter of the container 3.

 After the end of the pressing, the press stamp 4 is removed, the press residue is squeezed out of the container 3 and then it is separated. The finished product is pulled out of the matrix 5, if necessary, subjected to dressing, cut to measure and fed to the warehouse of finished products.

During the extrusion process, the container 3 can be mixed with a constant ratio of the speed V C / V R of the movement of the container to the speed of movement of the press stamp, which is in the range from about 1.05 to 1.3 times.

The level of the mechanical properties of the products and their distribution along the length is affected by the initial temperature of the workpiece 1, the pressing speed and the value K W of the ratio V C / V R of the speeds of movement of the container and the stamp. The leading movement of the container 3 allows you to further shift the peripheral layers of the workpiece 1, which leads to additional shear deformations in the extrudable material. This in turn allows you to further grind the cast structure of the workpiece 1 and thereby improve the mechanical properties of the products. In many cases, products with a uniform distribution of the mechanical properties of the metal along the entire length of the products are required. Maintaining the ratio V C / V R of the speeds of movement of the container and the press stamp constant during extrusion ensures a uniform distribution of the mechanical properties of the metal along the length of the products.

The constant ratio V C / V R of the speed of movement of the container to the speed of movement of the press stamp during the process allows you to simplify the design of the press and, therefore, reduce its cost by eliminating expensive control systems, control, installation of actuators to change the ratio of V C / V R speeds moving the container and the stamp during the extrusion process.

Pressing speed is an important characteristic of the extrusion process. With increasing pressing speed, the productivity of the process increases, but at the same time, as a result of the work of deformation in the workpiece, the amount of heat released increases. In turn, changing the temperature of the workpiece 1 significantly affects the process of dynamic recrystallization taking place in it, and, therefore, affects the structure of the resulting products, which in turn affects the level of mechanical properties. To compensate for the temperature changes in the workpiece 1, due to changes in the extrusion speed, it is necessary to change the value K W of the ratio V C / V R of the speeds of movement of the container and the stamp. For example, increasing the extrusion speed requires an increase in the ratio V C / V R , the speeds of movement of the container 3 and the stamp 4. This contributes to better heat dissipation conditions as a result of a more rapid movement of the container.

 The initial temperature of the workpiece largely determines the level of mechanical properties of the product, the permissible pressing speed. The influence of the temperature of the workpiece on the volumetric effect of the friction forces is also significant. The lower the temperature of the workpiece, the higher the resistance to deformation, the larger in width (and volume) the peripheral metal flow is formed as a result of the action of active friction forces induced in the workpiece by accelerated movement of the container. Therefore, with a decrease in the initial temperature of the workpiece, ceteris paribus, it is necessary to reduce the ratio of the speeds of movement of the container and the stamp.

In addition, during the extrusion of the workpiece 1, the initial uniform temperature field in the workpiece may change. Small heating of the container 3, the matrix 5 and the stamp 4 leads to the fact that during the extrusion process the workpiece 1 gradually cools. At the same time, its temperature has a significant effect on the process of dynamic recrystallization taking place in the preform 1, and therefore, on the structure of the obtained products, and this in turn affects the level of mechanical properties of the products. To obtain uniform mechanical properties of the products, it is necessary to compensate for the change in the conditions of recrystallization in the workpiece by changing the ratio V C / V R of the speeds of movement of the container and the stamp. For example, with decreasing the temperature of the workpiece 1 along the process, it is necessary to reduce the ratio V C / V R of the speeds of movement of the container and the stamp.

At the same time, in a number of industries it is necessary to obtain an uneven distribution of the mechanical properties of the metal along the length of the products. For example, at the ends of drill pipes where the tool joint is located, an elevated level of mechanical properties is desired. The same requirements apply to long-length aircraft parts at their mountings. Currently, according to existing technologies, such conditions for the distribution of mechanical properties along the length of the products cannot be ensured, and thickenings are specially made in critical places on the products. Obtaining products with thickenings (endings) is much more complicated and their cost is several times higher than conventional products. In the proposed method, by changing the ratio V C / V R of the speeds of movement of the container and the stamp and the temperature gradient in the workpiece during extrusion, it is possible to increase or decrease grinding metal structure, and thereby change the level of mechanical properties of products.

At the same time, as a result of numerous experiments, it was found that in the case where the ratio V C / V R of the speeds of movement of the container and the stamp exceeds 1.3, the peripheral layers of the workpiece 1 undergo intensive shear deformation, which is accompanied by dynamic recrystallization. This leads to a decrease in deformation resistance in these layers of the workpiece, because the dislocation density decreases sharply, and the grain size increases several times. Therefore, the level of mechanical properties in products decreases.

The use of the ratio V C / V R of the speeds of movement of the container and the press stamp less than K W <1.05 during extrusion leads to the localization of shear deformation in the boundary layer of the workpiece 1 and does not allow it to act on its central layer. The structure of these layers remains coarse-grained, and the products have a low level of mechanical properties.

 As mentioned above, in the process of extrusion as a result of the work of deformation in the workpiece 1, heat is generated, which significantly increases its initial temperature. It should be noted that this phenomenon is especially pronounced during the high-speed pressing process using the active action of friction forces. Significant changes in temperature in the workpiece 1 require a significant reduction in the speed of extrusion, and this significantly reduces the productivity of the process. In addition, as mentioned above, a change in the temperature of the workpiece 1 during the pressing process affects the dynamic recrystallization conditions occurring in it, therefore, the structure and, consequently, the level of mechanical properties vary significantly along the length of the products. This circumstance is in many cases undesirable. Heating of the workpiece 1 according to the proposed method, when the temperature of the front end is 1.8-1.1 times higher than the temperature of its rear end, allows you to compensate for the generated deformation heat. Heating the front end of the workpiece to higher temperatures than its rear part allows you to start the process with the required extrusion speed, and the product has no defects in the form of transverse cracks. In the process of extrusion in the workpiece 1, heat exchange processes with the working tool take place, so the residence time of the workpiece 1 in the container should be as small as possible. Therefore, it is most effective to use gradient-heated preforms 1 along the length in a high-speed pressing method with the active action of friction forces.

The choice of one or another temperature ratio between the front and rear ends of the workpiece depends on a number of factors. Using the SPAT method, it is most efficient to extrude hardly deformable aluminum alloys with high thermal conductivity. Therefore, to create a temperature gradient between the front t p and the rear ends t s of the workpiece with a ratio t p / t s > 1.8 is technically very difficult. With a decrease in the overall dimensions of the workpiece and especially its length, the possibility of obtaining a maximum temperature ratio t p / t s decreases. Creating a temperature gradient with a ratio of t p / t s <1.1 is impractical. The cost of creating a temperature gradient does not pay off due to a slight increase in productivity.

 Changing the extrusion rate using the speed controller 9 during the process allows you to more finely respond to changes in the temperature field in the workpiece 1 and thereby with high accuracy to maintain a constant temperature of the products at the exit of the matrix channel 5. This makes it possible to obtain an extremely uniform distribution of mechanical properties along the length products and significantly increase the productivity of the extrusion process.

 The table shows specific examples of the implementation of the proposed method of hot extrusion with the active action of the friction forces, while all tests were carried out on billets of difficult to deform aluminum alloys of the following composition (in percentage ratio): Cu 4.4; Mn 0.865; Mg-1.48; Fe-0.35; Si 0.31; Zn-0.145; Ti-0.0465; Ni-0.003; the rest is Al, on presses with an effort of 35 MH with a container diameter of 310 mm, coefficient. hoods λ -133.5.

 Thus, the inventive method of hot extrusion of metals with the active action of friction due to inducing on the contact surface of the workpiece and the container the friction forces of the active action and controlling them in the optimal range allows for the most efficient new extrusion method.

 In this method, friction forces carry certain contact layers of the ingot along, creating an accelerated peripheral metal flow. The width and speed of the peripheral flow relative to the central layers of the workpiece, depending on the task, can be adjusted in rational ranges by changing the ratio of the speeds of movement of the container and the press stamp in combination with the choice of temperature and speed conditions of the process.

 Patented extrusion method with the active action of friction due to the reduction of tensile stresses on the matrix belt allows to obtain the flow rate of the metal, exceeding these values by 5-6 times compared with the direct method and by 20-50% compared with the reverse method of pressing.

 Due to additional shear deformations in the ingot according to the patented method, it is possible to obtain mechanical properties of products that significantly exceed the properties of products obtained by reverse and direct methods. Only extrusion with the active action of friction forces due to the ability to flexibly and in an optimal range to control the metal extrusion process allows to obtain products either with a uniform distribution of mechanical properties along the length and cross section of the products, or with a predetermined distribution of them along the length of the products.

 By regulating in the rational range the magnitude of additional shear deformations in combination with the optimal temperature interval for heating the ingots, it is possible to obtain products without a large-crystalline rim.

 When extruding a metal with the active action of friction forces by creating a favorable direction of these forces on the contact surface between the press washer and the metal and controlling them in the optimal range, it is possible to practically eliminate the process of formation of the press tension and, accordingly, reduce the press size by 2–3 times -residue, thereby increasing the yield of products to 90-95%. By creating compressive 5 stresses on the surface of the workpiece in the optimal range, some surface microscopic defects can be eliminated. product objects. In addition, rational extrusion modes can reduce residual stresses on the surface of products. These circumstances make it possible to obtain products with increased corrosion resistance.

In addition, the patented method allows to achieve high extrusion speeds and thereby reduce the time spent by the ingot in the container within a minute. Such conditions make it possible to use ingots with gradient heating along the length with high efficiency, which in turn makes it possible to increase the productivity of the entire process by an additional 15-20%
The patented hydraulic extrusion press contains a frame 10 (Fig. 1), on which the front 11 and rear 12 crossbars are mounted, between which the container 3 and the crosshead 8 are mounted with the possibility of axial reciprocating movement on the guides (not shown). cross cylinders 12 are equipped with power cylinders: the main power cylinder having a cylindrical body 15 and a plunger 14 and retour cylinders (not shown for simplicity)). The plungers 14 of the main and retour cylinders are rigidly connected to the traverse 8.

 At least one stabilization cylinder having a housing 15 and a plunger 16 is installed on the rear cross member 12. Given the rational arrangement, either the housing or the plunger can be mounted on the rear cross member, then another element of the stabilization cylinder is mounted on the cross beam, respectively. To reduce the overall dimensions of the press and according to the technology used, two or more stabilization cylinders can be installed on the press. Stabilization cylinders act as a throttling device. In FIG. 1, as an embodiment, two stabilization cylinders are shown. On the rear cross member 12 (as well as one of the embodiments), cylindrical housings 15 of stabilization cylinders are mounted, and their plungers 16 are rigidly connected to the traverse 8. In the plungers 16 there are axial channels 17 communicating with the pipe 18. Pipelines 18 connect the internal cavity 19 stabilization cylinders with an internal cavity 20 of an additional cylinder having a cylindrical body 21 and a plunger 22, which are coaxially mounted on the cross beam 8. On the plunger 22 of the additional cylinder, a stamp 4 is coaxially mounted with a rigid fastener ennoy it press washer 23.

 On the traverse 8, protrusions 24 are made, interacting with the tides 25 on the container 3. To move the container on the press, the cylinders of the forward and reverse motion of the container are installed. Given the rational layout, their cylindrical bodies can be mounted either on the front cross member or on the rear cross member of the press. As one embodiment of FIG. 1, the cylindrical bodies 28 and 29 of the reverse and forward cylinders of the container 3 are mounted on the front cross member 41, and their plungers 26 are mounted on the container 3.

 A window 30 is made in the front cross member 11 into which the pressed product passes. Coaxial with this window 30, on the front cross member 11 in the universal socket 31, a hollow die 6 with a replaceable die 5 is installed. A device (not shown in Fig. 1) for transferring the die 5 through the container 3 is also installed on the front cross member 11 can be mounted a knife 32 for separating press residues, as well as the feeding mechanism 7 of the workpieces with a clamping device 33.

 The cavity 2 of the container 3 from two opposite sides includes a continuous press stamp 4 with a press washer 23 and a hollow press stamp 6 with a die 5, between which the pressed workpiece 1 is placed. On pipelines suitable to the inner cavity 35 of the main power cylinder of the highway 34 high pressure, installed the filling valve 36 and the regulator 9 of the movement speed of the beam 8. The pipelines of the low pressure line 37 are also suitable for the press.

 A device for extruding using active friction forces works as follows.

 In the initial position, the plunger 22 of the additional cylinder is extended as far as possible from the housing 21 (to the right in Fig. 1), and the plungers 14 and 16 of the main and stabilizing cylinders, as well as the reture cylinders, are in the extreme left position.

The heated preform 1 is fed to the feeding mechanism 7 and secured with a clamp 33 so that approximately one third of the preform 1 protrudes from it from the side facing the container 3. Then, using the feeding mechanism 7, the preform 1 is lifted onto the press axis. Then the return cylinders 26, 28 of the container 3 are turned on, and the latter is pushed onto the free part of the workpiece 1 located on the feed mechanism 7. The return cylinders are turned off at a time when there is a distance of about 30-50 mm from the feed mechanism 7 of the workpieces 1. Next, the feeding mechanism is removed and, by the further course of the container 3 (according to the drawing to the left), the workpiece 1 is pushed into the cavity 2 of the container 3. At the same time, the hollow die 6 completely leaves the container 3, and a matrix is put on it with a special device (not shown). 5. Liquid is supplied from the pipeline of the high-pressure line 34 to the power master cylinder, and the crosshead 5 makes a small idle stroke H I b moreover, the protrusions 24 on the traverse 8 are in contact with the tides 25 on the container 3, and all these movable elements begin to move at the same speed to the right. In this case, the internal cavity of the return cylinders of the container 3 and the internal cavity of the retur cylinder of the crosshead 8 are connected to the pipelines of the low pressure line 37, thereby discharging the liquid. When the traverse 8 moves to the right, it also pulls the plungers 16 of the stabilizing cylinders, while in the cylindrical bodies 15 space is gradually freed up. Since pressure is transmitted through the blank 1 to the press stamp 4, and he, in turn, transfers it to the plunger 22 of the additional cylinder, the liquid from the internal cavity 20 of the additional cylinder flows into the released cavities of the stabilizing cylinders. Stabilization cylinders act as a throttling device. In this case, a smooth uniform recession of the plunger 22 of the additional cylinder occurs, and therefore, the press stamp 4 lags behind the movement of the container 3. The speed V R of the movement of the press stamp 4 at this time is determined as the difference between the speed V b of the movement of the beam 8 and the speed V a of movement plunger 22 additional cylinders.

V R -V b -V a ,
where V b the speed of the traverse 8;
V a the speed of movement of the plunger 22 of the additional cylinder.

The speed V c of the movement of the container 3 is the same with the speed V a of the movement of the beam 8. The speed V b of movement of the beam 8 and the speed V a of recession of the plunger 22 of the additional cylinder are respectively directed in opposite directions. Therefore, the value of the kinematic coefficient K W is equal to the quotient of dividing the speed V b of the crosshead 8 by the difference in the speeds of the crosshead V b and the plunger V a of the additional cylinders.

K W -V c / V R -V b / (V b -V a ),
where K W kinematic coefficient;
V c the speed of movement of the container;
V R stamp travel speed;
V b the speed of the traverse;
V a the speed of movement of the plunger of the additional cylinder.

This value K W of the ratio V C / V R of the speeds of movement of the container V c and the stamp V R is automatically maintained throughout the entire working cycle of the pressing.

In this case, it is only necessary to stabilize the speed of movement of the plunger 14 of the main cylinder using the speed controller 9. This ensures that the container 3 on the side surface of the workpiece 1 forces the friction of the active action, directed towards the outflow of metal. The value K W of the ratio V C / V R of the speeds of movement of the container V C and the stamp V R are determined by the ratio of the dimensions of the inner cavity 20 of the additional cylinder of the inner cavities 19 of the stabilizing cylinders.

 After reaching the set value of the press balance, the fluid supply from the high-pressure line 34 is stopped by closing the filling valve 36, while the inner cavity 35 of the master cylinder communicates through the same filling valve 36 with the low-pressure line 37.

 The cavities of the reture cylinders (not shown in FIG.) Are connected to the high-pressure line 34 and, under their action, the crosshead 8 returns to its original (left) position. At the same time, from the inner cavity 19 of the stabilization cylinders, the liquid is forced into the inner cavity 20 of the additional cylinder, the additional plunger 22 is extended to its original (extreme right) position.

 Further, the return cylinders of the container 3 (or simultaneously with the removal of the beam 5 continue a slight movement of the container 3 to the right until it stops in the stroke limiter (not shown in Fig. 1) of the container 3, while the press residue is removed from the cavity 2 of the container 3. With a knife 32 of it Next, the container travel limiter is removed and the container 4, using the container movement cylinders (27.29), is shifted all the way into the front cross-section 11, while the matrix 5 leaves the container 3 from the side of the crosshead 8, after which it is removed from the hollow die 6. Gave th cycle can be repeated.

The installation of additional cylinders (21, 22) and stabilizing cylinders (15, 16), which perform the functions of a throttling device and are hydraulically interconnected, allows automatically, without any external adjustment, to obtain the optimal constant value K W of the ratio V C / V R of the speeds of movement of the container and press -stamps, i.e. fully implement the specified method of hot extrusion with the active action of friction forces. This device allows you to automatically maintain the necessary optimal ratio V C / V R of the speeds of movement of the container and the stamp even with a constant change in the speed of movement of the main plunger and, accordingly, the associated beam 8.

 The design of additional cylinders and stabilization cylinders is very simple, and they can be easily installed on any press.

 The hydraulic extrusion press may have an additional hydraulic connection in the form of a pipe 38 (Fig. 2), carried out by connecting the internal cavity 19 of the stabilization cylinder to the low-pressure line 37. A regulator 39 can be installed on the additional pipe 38, in which, for example, a controlled valve 40 and an uncontrolled spring-loaded valve 41 can be installed.

 An additional pipeline 38 allows you to make the press traverse 8 idle strokes of any size. In the absence of this connection, when the yoke 8 moves in the internal cavities 19 of the stabilizing cylinders, space is freed up, while there is no pressure on the press stamp 4 and the liquid is not squeezed out of the additional cylinder. This leads to the fact that a vacuum is created in the inner cavity 19 of the stabilization cylinders, leading to air suction into the hydraulic system. This condition of the hydraulic system is very dangerous, and it becomes inoperative.

 The implementation of additional hydraulic communication, made in the form of a pipe 38, allows, during idling, the beam 8 to supply liquid from the low-pressure line 37 to the released internal cavity 19 of the stabilization cylinders, which prevents air from entering the hydraulic system.

For a given value K W of the ratio V C / V R of the speeds of movement of the container and the stamp, the cross-sectional area F s of the stabilizing cylinder is selected from the relation
F S -F a (1-1 / K W ),
Where
F S cross-sectional area of the stabilizing cylinder;
F a the cross-sectional area of the additional cylinder;
K W value of the ratio V C / V R of the speeds of the container V C and the stamp V R ;
and the length of the internal working cavity of the additional cylinder is determined
H a = H w b (1-1 / K w ), (4)
Where
H a the length of the working cavity of the additional cylinder;
H w b the value of the maximum possible stroke of the traverse 8.

In the presence of several stabilization cylinders, the area F s of their cross section is summed up ΣF s
To automatically obtain the required value K W of the ratio V C / V R of the speeds of the container V C and the stamp V R and the reliable operation of the press units during the extrusion process, it is necessary to perform various press structural elements in strict accordance with each other. The length of the cylinder body 15 and the plungers 16 is chosen equal to the length of the body 13 of the main power cylinder and its plunger 14. The choice of such relations allows not to limit the working stroke of the beam 8. To exclude pressure multiplication in the internal cavity 20 of the additional cylinder, the cross-sectional area of the additional plunger 22 is equal to the total transverse sections of all power cylinders carrying out the working stroke of the traverse 8.

The stroke of crosshead 8, plungers 14 of power cylinders and plungers 16 of stabilization cylinders consists of idle H I b and worker H w b moves. In the calculations, the maximum possible stroke is used, depending on the maximum length of the workpiece 1, which can be placed and pressed out of the accepted length of the container 3. The total volume W s of the internal cavities 19 of all stabilization cylinders W i s (W s = ΣW i s ), released only during the working stroke, should be equal to the maximum volume W a of the free internal cavity 20 in the additional cylinder (with the maximum possible extended plunger 22 to the right in Fig. 2)
W a = W s ; W a = F a H a ; F a H a = ΣF s H w b (5)
Where
W a the cross-sectional area of the additional cylinder;
F s the cross-sectional area of all stabilization cylinders;
H a the length of the working cavity of the additional cylinder;
H w b value of the maximum stroke of the plunger of the stabilization cylinders.

The value K W of the ratio V C / V R of the speeds of the container V C and the stamp V R is determined by the ratio:
K w = V c / V R = (H c / τw) / (H R / τw) = H c / H R , (6)
Where
H c the amount of travel of the container 3;
H R stroke size of the stamp 4;
τw travel time.

The stroke H c of the container 3 is equal to the stroke H w b traverse 8, therefore, it is equal to the stroke H w s plungers 16 cylinder stabilization.

K w = H w s / (H w s -H a ) (7)
Thus, to obtain the specified ratio V C / V R of the speeds of the container V C and the stamp V R throughout the entire stroke, the length of the internal free cavity 20 of the additional cylinder must be
H a = H w s / (1-1 / K w ) (8)
Substituting the obtained expression (8) into expression (5), we obtain the necessary ratio between the cross-sectional area F a of the additional cylinder and the total cross-sectional area F S of all stabilization cylinders

Figure 00000002

At least two forcing rams can be installed on the hydraulic extrusion press, each of which is made in the form of a cylindrical body 42 with a plunger 43 located therein. Given the rational arrangement, either the housing or the plunger can be mounted on the rear cross member, then another element, respectively the boosting power cylinder is mounted on the traverse. Alternatively, in FIG. 2, the cylindrical body 42 of the boosting power cylinder is fixedly mounted on the rear cross member 3, and the plunger 43 on the crosshead 8, and the inner cavity 44 of each of them communicates with the high 34 and low 37 fluid pressure lines.

 With this embodiment of the hydraulic press, if necessary, to idle, the liquid from the high-pressure line 34 is supplied only to the internal cavity 44 of the boosting cylinders. At this time, only liquid from the low pressure line 36 enters the master cylinder. This saves a large amount of expensive fluid in high-pressure lines 34.

 To make the stroke, the traverse 8 in the main cylinder stop supplying fluid from the line 37 low pressure and begin to supply fluid from the line 34 high pressure. Fluid can continue to be supplied to the boost cylinders from the high pressure line 34. If only the main cylinder forces are sufficient for extrusion, liquid from the low-pressure line 37 falls into the boosting cylinders.

 In a hydraulic extrusion press, the internal cavity 44 of each of the boosting cylinders can be hydraulically connected to the internal cavity 20 of the additional cylinder via a channel 45 in the plunger 43 and a pipe 46.

This hydraulic connection allows the use of boost cylinders in addition to stabilizing cylinders, i.e. they can act as a throttling device. In this case, when calculating the total cross-sectional area ΣF s of the stabilizing cylinders, the cross-sectional area of all boosting cylinders is also taken into account.

 In the hydraulic extrusion press, valves 47.48 can be installed between the internal cavities 19, 44 of each hydraulic cylinder hydraulically connected to the additional cylinder and the mains and high 34 and low 37 pressures.

 Before starting these valves (47 and 48) are open. At the beginning of idling, liquid 48 enters the boosting cylinders from the high-pressure line 34, and liquid 47 passes through the valve 47 to the stabilization cylinders from the low-pressure line 37. After the end of the pressing and the beginning of the expiration of the metal of the workpiece, the valves 47 and 48 are closed, can be closed, after which liquid begins to flow from the internal cavity 20 of the additional cylinder into the stabilization cylinders and into the forcing cylinders.

 In a hydraulic extrusion press, the hydraulic connection 18, 46 between the internal cavity 20 of the additional cylinder and each of the internal cavities 19, 44, respectively, of the stabilization cylinders and the boost cylinders hydraulically connected to it, may contain valves 49 and 50, respectively.

 Before starting the press, these valves 49 and 50 are closed. During idling and the subsequent stage of pressing the workpiece in the container 3, the valves 49 and 50 continue to be closed. After extrusion and the beginning of the flow of metal into the channel of the matrix 5, valves 47 to 48 are closed and valves 49 and 50 open simultaneously. Moreover, due to the force of the plunger 22 of the additional cylinder, the liquid 43 from the internal cavity 20 of the additional cylinder begins to flow into the internal cavity 19 of the cylinder stabilization, and into the internal cavity of 44 boosting cylinders.

As already described above, as a result of this, the plunger 22 of the additional cylinder starts to sink (in FIG. 1, go to the left), and the speed V R of the movement of the press stamp 4 becomes lower than the speed V C of the movement of the container 3. Active friction forces occur on the side surface of the workpiece 1 directed towards the outflow of metal.

Since, in addition to the stabilization cylinders, the fluid flows from the additional cylinder into the cavity 44 of the boosting cylinder, the lag of the press stamp 4 will be greater than when only stabilizing cylinders are connected. This allows you to get another from the optimal interval ratio V C / V R the speed of movement of the container V C and the stamp V R. Thus, by varying the various combinations of connecting the stabilizing and boosting cylinders, using valves 49 and 50 it is possible to automatically use different ratios V C / V R of the speeds of movement of the container V C and the stamp on the same press during the entire working stroke, depending on the production need V r .

 On a hydraulic extrusion press, the valve 48 can be made three-position: the first position is “closed”, the second position is “open” to the high-pressure line 34, the third position is “open to the low-pressure line”. To supply fluid from the high-pressure line 34 to the boosting cylinders, the valve 48 is placed in the second position and the valve 51 is opened. To supply the fluid from the high-pressure line 34, the valve 48 is placed in the third position and the valve 51 is closed.

The hydraulic extrusion press may contain a throttling device (Fig. 3), consisting of a housing 52 with two holes: input 53 and output 54; a spool 55 with a through cavity 56 is installed inside the housing. The spool 55 interacts with the spring 57 on the one hand and the spring 57 on the other hand spool 55 has a housing 58 of the hydraulic cylinder rigidly associated with the housing 52. The piston 59 of this cylinder 58 with one end fixedly secured to the spool 55. The configuration and geometrical dimensions of the through cavity 67 define the magnitude ratio V C / V R with orostey mutual displacement of the container V C and the ram V R. The cavity 56 is hydraulically connected via a pipe 60 to the inner cavity 20 of the additional cylinder through an inlet 53 in the housing 52. On the other hand, the through cavity 56 in the spool 55 through the outlet 54 in the housing 51 is connected to the low-pressure line 37 via a pipeline 61. Internal the cavity 62 of the cylinder body 58 is also connected via a pipe 63 to the internal cavity 20 of the additional cylinder.

 A cover 64 is mounted on the housing 52 of the throttling device from the side of the spring 57. A valve 65 can be installed on the pipe 60 between the through cavity 56 of the spool 55 and the internal cavity 20 of the additional cylinder.

 Such a press works as follows. After placing the heated billet 1 (Fig. 2), a high pressure is supplied to the container 3 in the forcing cylinders 42, 43 through the open valves 48, 51, the crosshead 8 starts to idle. While the valve 47 is open, and the filling valve 36 is closed to the high pressure liquid and open to the low pressure liquid, therefore, the low pressure liquid enters the internal cavity 35 of the main cylinder 13, 14 and the internal cavities 19 of the stabilization cylinders, while the valves 49, 50 and 65 are closed. After the press stamp 4 comes into contact with the workpiece 1, and that in turn with the die 4, the filling valve 36 is opened for the passage of the high pressure fluid and is closed for the passage of the low pressure fluid. The stage of pressing the workpiece begins, requiring maximum energy costs.

After the end of the pressing and the beginning of the outflow of metal through the channel of the matrix 5, the valves 47, 48, 51 are closed, and the valves 49, 50 and 65, all or each individually, are opened. The liquid from the inner cavity 20 of the additional cylinder begins to flow into the stabilization cylinders, the boost cylinders and through the valve 65 it goes to the through hole 56 in the spool 55 and to the cavity 62 of the cylinder 58 of the throttle device. Further, the liquid passes through the hole 56 in the spool 55 and enters through the outlet 53 into the low pressure line 37 through the pipe 61. As in addition to the stabilization cylinders and the boost cylinders, the liquid is additionally drained from the inner cavity 20 of the additional cylinder to the low pressure line 37 through the pipe 61, then the plunger 22 of the additional cylinder 21, 22 is recessed faster, and, therefore, the ratio V C / V R of the speeds of movement of the container V C and the stamp V R increases.

The fluid from the additional cylinder simultaneously acts on the plunger 58 of the throttle device, and that in turn affects the spool 55, trying to move it (in Fig. 3 to the right). The spring 57 restrains it from this movement, which abuts against the spool 55 on one side and the cover 64 on the other side. Therefore, the spool 55 is moved every moment of time until the fluid pressure on the plunger 59 is compensated by compressing the spring 57. Then, as the process proceeds extruding, the side surface of the workpiece 1 decreases, so the proportion of the force transmitted to the workpiece 1 through the container 3 also decreases, and the proportion of the force transmitted through the press stamp 4 increases. As a result, the pressure in the inner cavity 20 of the additional cylinder is constantly increasing, and therefore, the effect on the plunger 59 is constantly increasing. As a result of this action, the plunger 59 and the spool 55 are constantly moving (to the right), compressing the spring 57 more and more. When moving the spool 55, its through cavity 56 at different points in time will be differently located relative to the input 53 and output 54 holes in the housing 52 of the throttling device. The configuration of the through cavity 56 may be of variable cross-section along the length of the spool 55. Thus, in the course of the extrusion process in the additional throttling device, various passage sections for liquid are obtained. As a result of this, a different volume of liquid passes through the cavity 56 in the spool 55 at different times, and, consequently, the rate of recession of the plunger 22 of the additional cylinder will be variable. Based on the foregoing, it can be seen that the ratio V C / V R of the speeds of movement of the container 3 and the stamp 4 is variable during the extrusion cycle. The law of change in the ratio of V C / V R speeds is determined by the configuration and geometric dimensions of the through channel 56 in the spool 55. The law of change in the ratio of V C / V R of the speeds of movement of the container V C and the stamp V R is selected in the optimal interval indicated above, and it depends on the extrudable material and process parameters.

In the case when it is necessary to switch to a constant ratio V C / V R of the speeds of movement of the container V C and the stamp V R during the process, the valve 65 is closed.

In a hydraulic extrusion press, the cover 64 (Fig. 3) on the housing 52 of the additional throttling device can be mounted axially displaceable to control the amount of preload of the spring 57. By changing the amount of preload of the spring 57, the law of movement of the spool 55 during extrusion can be changed, and therefore, to adjust the law of change in the ratio V C / V R of the speeds of movement of the container and the stamp.

 An additional throttling device may have a spindle 66 fixedly mounted on the end of the spool 55 from the spring side 57. The cover 64 has a through hole 67 for the spindle 66 to pass through. The hole 67 in the cover 63 and the spindle 66 are mated, for example, threaded.

During the movement of the spool 55 (to the right in Fig. 3), the screw 66, moving into the hole 67 of the cover 64, rotates while rotating the spool 55. As a result of this rotation, the hole 56 in the spool 55 changes its position relative to the holes 53 and 54 in the housing 52 additional throttling device in addition to the axial also in the tangential direction. Thus, without altering the configuration of the cavity 56 in the spool 55, it is possible to correct the law of changing the ratio V C / V R of the speeds of movement of the container and the stamp during the extrusion process.

 The cylindrical housing 21 and, accordingly, the plunger 22 of the additional cylinder can be made stepwise (Fig. 4). As a result of this embodiment, the steps of the plunger 22 are formed of a larger diameter 68 and a smaller diameter 69 and two internal cavities: an annular 70 and a cylindrical 71. The internal cavities 70 and 71 communicate hydraulically with each other using a pipe 72.

 The additional cylinder with a stepped plunger 68.69 works similarly to the additional cylinder with a cylindrical plunger 22 (Fig. 2), the operation of which is described above.

However, for reliable operation of any hydraulic cylinders, it is necessary to have sufficiently large guides for their plungers (at least two to three diameters of the plunger itself). This condition leads to an increase in the overall dimensions of the cylinders and, therefore, of the elements (in this case, the width of the beam) in which they are placed. At the same time, in order to obtain the necessary ratio V C / V R of the speeds of movement of the container and the press stamp and to avoid multiplication in the internal cavity of the cylinder, the cross-sectional area of the additional cylinder must be sufficiently large.

 The implementation of the additional cylinder 21, 22 stepped allows you to save the necessary cross-sectional area of the additional cylinder, have a large direction for the plunger 22 and reduce the dimensions of the beam 8. This is due to the fact that as a result of hydraulic communication through the pipe 72, the cross-sectional area of the plunger 22 is determined by its larger stage 68. The main guide element of the plunger 22 is the stage 69 of the small diameter of the housing 21 of the additional cylinder and the plunger 22. This stage 69 of the plunger 22 lnyaetsya considerable length (several diameters of most stages), and the step 68 of larger diameter of the auxiliary cylinder is performed a small length. This embodiment of the larger stage 68 of the plunger 22 of the additional cylinder can significantly reduce the size of the pressing beam 5, and therefore the overall dimensions of the press.

 A smaller stage 69 of the additional cylinder can be partially placed in the main plunger 14 of the press, as shown in FIG. 4. The operation of the press with this embodiment of the plunger is carried out similarly to that described above in FIG. 2.

 The location of the part of the plunger 22 of the additional cylinder in the body of the main plunger 14 allows you to further reduce the size of the pressing beam 8 and, therefore, the entire press.

 Patented hydraulic extrusion press allows you to fully implement the pressing method with the active action of friction forces.

 The design of the patented hydraulic extrusion press is simple and reliable in operation and automatically throughout the work cycle allows you to maintain the necessary ratio of the speeds of movement of the container and the stamp. Using a patented press by simply switching the valves, you can get the ratio of the speeds of movement of the container and the stamp required for the manufacture of a particular product.

 To obtain products with a regulated distribution of mechanical properties along the length of the products on the press, it is possible to automatically perform a smooth change over the entire working cycle in the optimal range of the ratio of the speeds of movement of the container and the stamp.

Claims (18)

1. The method of hot extrusion of metal with the active action of friction, including heating the workpiece to be extruded, placing it in a container and extruding it through a matrix that determines the shape and geometric dimensions of the finished product using a press stamp while moving the container and the stamp with speed the movement of the container, a greater speed of movement of the press stamp, and the speed V with the movement of the container is set depending on the speed of extrusion, characterized in that the speed V from the movement of the container is set depending on the speed of extrusion or on the temperature field of the workpiece, the ratio of the speeds of movement of the container and the stamp during the extrusion process is maintained in the range of 1.05 1.3, and a larger value of the ratio of speeds of movement of the container corresponds to a larger value of the speed of extrusion and stamps.
2. The method according to claim 1, characterized in that in the process of extruding the workpiece, the ratio (V c / V r ) of the speeds of the container and the stamp is kept constant.
3. The method according to claim 1, characterized in that in the extrusion process the ratio (V c / V r ) of the speeds of the container and the stamp is changed within the range of 1.05 1.3.
 4. The method according to claim 1, characterized in that the ratio of the heating temperature of the front end of the workpiece to the heating temperature of the rear end of the workpiece is 1.8 1.1.
5. The method according to any one of claims 1 to 4, characterized in that during the extrusion process, the speed V r of the movement of the stamp is changed depending on the change in the temperature gradient of the workpiece along its length.
 6. A hydraulic extrusion press comprising a front cross member and a rear cross member rigidly fixed to the bed with a main power cylinder and container moving cylinders fixedly connected thereto, communicating with high and low pressure lines, a throttling device connecting the high pressure line to the container moving cylinders, installed with the possibility of reciprocating movement along the longitudinal axis of the bed and coaxially located press stamp associated with the plunger rum of the master cylinder, a container and a hollow stamp fixed on the front cross member, characterized in that the crosshead is rigidly fixed on the plunger of the main cylinder, on which an additional cylinder is placed, on the plunger of which the stamp is fixed, the additional cylinder is hydraulically connected to the throttling device made in the form of at least one stabilizing cylinder, consisting of a cylindrical body with a plunger placed in it, moreover, one of these stabilizing elements the cylinder is mounted on the rear cross member, and the other is rigidly connected to the traverse, while the inner cavity of the stabilizing cylinder is in communication with the inner cavity of the additional cylinder.
 7. The press according to claim 6, characterized in that the inner cavity of the stabilizing cylinder is in communication with the low pressure line.
8. The press according to claim 6, characterized in that for a given value of the ratio V c / V r of the speeds of the container and the stamp the cross-sectional area (F s ) of the stabilizing cylinder is
F s F a (1 1 / K w ),
where F s the cross-sectional area of the stabilizing cylinder;
F a the cross-sectional area of the additional cylinder;
K w the ratio of V c / V r speeds of the container V c and the stamp V r ,
and the length h a of the working cavity of the additional cylinder is
H a = H w b (1-1 / K w ),
where H a the length of the working cavity of the additional cylinder;
H w b - the maximum length of the stabilization slave cylinder.
 9. The press according to claim 6, characterized in that it is equipped with at least two forcing power cylinders, each of which is made in the form of a cylindrical body with a plunger located in it and one of these elements of each forming power cylinder is fixedly mounted on one of the cross members and the other on the traverse, and the internal cavity of each of them is connected to the low and high pressure mains.
 10. The press according to claim 9, characterized in that the inner cavity of each cylinder is hydraulically connected to the additional cylinder of the corresponding high and low pressure line through the valve.
 11. Press according to any one of paragraphs.6 to 9, characterized in that the inner cavity of each forcing cylinder is hydraulically connected to the inner cavity of the additional cylinder.
 12. Press according to any one of paragraphs.6 to 9, characterized in that the inner cavity of the additional cylinder is hydraulically connected to the inner cavity of each associated power cylinder through a valve.
 13. Press according to any one of paragraphs. 6 to 9, characterized in that it is equipped with an additional throttling device made in the form of a housing with holes and a lid, inside which a spring-loaded spool with a through cavity is installed, the geometric dimensions and configuration of which determine the magnitude of the speed of mutual movement of the container and the stamp the through cavity is hydraulically communicated through a corresponding hole in the housing of the additional throttling device with the internal cavity of the additional cylinder and the line a low pressure side of the spool opposite the spring-loaded side spool mounted cylinder body which is rigidly connected to the housing of the auxiliary restricting unit, while a plunger is rigidly connected to the spindle, the inner cavity of this cylinder is hydraulically communicated with the inner space of the auxiliary cylinder.
 14. The press of claim 13, wherein the cover of the additional throttling device is mounted axially displaceable to control the amount of pre-compression of the spool spring.
 15. Press according to claim 13, characterized in that the additional throttling device is provided with a lead screw fixedly mounted on the end of the spool from the spring side, and a through hole is made in the cover, in which the screw is placed with the possibility of controlling their reciprocal reciprocating movement.
 16. Press according to any one of paragraphs.13 to 15, characterized in that it is equipped with a valve installed between the additional cylinder and the additional throttling device.
 17. The press according to claim 6, characterized in that the cylindrical body and, accordingly, the plunger of the additional cylinder are made stepwise, and the cavities formed by these steps are hydraulically interconnected.
 18. The press according to claim 6, characterized in that the stage of the additional cylinder facing the plunger of the main power cylinder is partially placed in this plunger and is rigidly connected to it.
RU93050907A 1993-11-10 1993-11-10 Method for hot extrusion of metal at active action of friction forces and hydraulic extrusion press for performing the same RU2105621C1 (en)

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RU93050907A RU2105621C1 (en) 1993-11-10 1993-11-10 Method for hot extrusion of metal at active action of friction forces and hydraulic extrusion press for performing the same
PCT/RU1993/000303 WO1995013150A1 (en) 1993-11-10 1993-12-15 Process for the hot extrusion of metal with the active assistance of friction forces, and a hydraulic extrusion press for carrying out this process
EP94906412A EP0747144A1 (en) 1993-11-10 1993-12-15 Process for the hot extrusion of metal with the active assistance of friction forces, and a hydraulic extrusion press for carrying out this process

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RU2105621C1 true RU2105621C1 (en) 1998-02-27

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013012352A1 (en) * 2011-07-15 2013-01-24 Федеральное Государственное Бюджетное Образовательное Учреждение Высшего Профессионального Образования "Уфимский Государственный Авиационный Технический Университет" (Фгбоу Впо "Угату") Ultrafine-grained aluminium alloys for electrical products and method for producing same (variants)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3366534B2 (en) * 1996-09-19 2003-01-14 山陽特殊製鋼株式会社 Warm or hot front-rear simultaneous extrusion high-speed die forging method and apparatus
DE10346992A1 (en) * 2003-10-07 2005-05-12 Alcan Tech & Man Ag Temperature controlled material forming process and apparatus for carrying out the process
CN101985150B (en) * 2010-08-02 2013-06-12 天津市天锻压力机有限公司 Hydropress with compound function of isothermal forging and electrode pressing
WO2016070027A1 (en) 2014-10-31 2016-05-06 Massachusetts Institute Of Technology Compositions and methods for arranging colloid phases

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3670542A (en) * 1969-12-04 1972-06-20 Reynolds Metals Co Extrusion method and apparatus
FR2196860B1 (en) * 1972-08-24 1977-08-05 Morane Somua Pr Sses Mat
SU623604A1 (en) * 1976-11-22 1978-09-15 Предприятие П/Я Г-4361 Article-manufacturing method
SU645721A1 (en) * 1977-01-04 1979-02-05 Московский институт стали и сплавов Article-pressing method
SU676347A1 (en) * 1977-05-24 1979-07-30 Предприятие П/Я В-8173 Tuve-pressing method
JPS5625324B2 (en) * 1977-10-15 1981-06-11
DE3023388A1 (en) * 1980-06-23 1982-01-21 Schloemann Siemag Ag INDIRECT METAL EXTRUSION PRESS AND WORKING METHOD FOR REMOVING FROZEN BLOCKS FROM SUCH A PRESS

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013012352A1 (en) * 2011-07-15 2013-01-24 Федеральное Государственное Бюджетное Образовательное Учреждение Высшего Профессионального Образования "Уфимский Государственный Авиационный Технический Университет" (Фгбоу Впо "Угату") Ultrafine-grained aluminium alloys for electrical products and method for producing same (variants)

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