DE2239912A1 - METHOD AND DEVICE FOR HYDROSTATIC EXTRUSION - Google Patents

Description

PATENT LAWYERS

DR. W. SCHALK DIPL.-1NG. P. WIRTH DI PL.-I NG. G. DAN N EN BERG DR. V. SCHMIED-KOV / ARZIK · DR. P. WEI NHOLD · DR. D. GUDEL

6 FRANKFURTAM MAIN GR. ESCHENHEIMER STRASSE 39

U.S. Serial No. 172.039

August 11, 1972 BT / -mr-

PW / Si

Batteile Memorial Institute

505 King Avenue, Columbus, Ohio, USA

Method and device for hydrostatic extrusion

The invention disclosed in more detail below relates to extrusion technology and lubrication in extrusion, namely the extrusion of a metal billet which, by the application of high pressure, is forced through a die whose cross-sectional area is smaller than that of the original billet. The invention provides a method and a device for reducing the required power or energy consumption of the high pressure source or the high pressure drive by reducing the pressure required to overcome the friction on the wall of the recipient and generated and applied in normal or conventional extrusion processes to zero or almost Zero or substantially reduced . The invention also has the advantage that conditions for hydrostatic or quasi-hydrostatic extrusion are created without the known

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th prior art occurring complicated and cumbersome Facilities or procedures are required.

According to the state of the art, the basic idea known as hydrostatic extrusion is of particular importance a pressurized flowing medium exerts the force which squeezes the ingot out through the die opening. The advancing piston has the task of maintaining a high pressure of the flowing medium, and not to advance the ingot by striking the front end of the ingot that lies away from the extrusion nozzle. In the It is common practice in the practice of the extrusion process to devote considerable time to an extrusion operation for the supply and forwarding of the flowing medium, i.e. for the injection, the compression, the relaxation and the squeezing of this medium is lost. The requested results in terms of production quantities or speeds (Extrusions per unit time) are significantly less than those usually performed using conventional Extrusion processes and devices can be achieved.

One of the advantages of the present invention is that production quantities or speeds are made possible which are the same or approximately the same as those that are achieved by conventional extrusion in either a hydraulic or mechanical press, while according to the invention nevertheless the known advantages of simple hydrostatic extrusion can be achieved.

The prior art is also the suggestion of importance, a hydrostatic extrusion process with so-called elevated feed bars (billet-augmented hydrostatic extrusion)

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make, 'in which the punch causing the feed is in contact with the ingot during an extrusion process remains, hereinafter referred to as "extrusion with increased billet feed" referred to as. In the method of U.S. Patent 3,382,691, Green, the primary purpose is to Application of pressure with increased billet advance in order to maintain better control of the influence of the billet, than it is achieved in a simple hydrostatic extrusion process, in particular during a state as so-called "stick-slip", i.e. alternating plugging or Sticking and slipping is known, in which the bar moves intermittently instead of at a constant rate Speed to be advanced. The pressure exerted by the punch during the billet extrusion process with increased feed is carefully monitored and regulated in such a relationship to the pressure of the flowing medium, that the ingot is not in the sizeable ring-shaped Gap compresses or bulges into it through plastic deformation, the upright between the bar and the recipient is obtained. To ensure constant pressure levels both for the flowing medium and for the reinforced billet extrusion feed process during the extrusion of the billet becomes that existing in the recipient contained the billet Volume excess of flowing medium continuously in a separate hydrostatic pressure vessel flowing back into it through an axial bore of the extrusion die tapped. This setup is necessarily more complicated and expensive than a simple one hydrostatic extrusion with a comparable size of the. Pressure levels of the flowing medium. Also with this device or this method, the output rate or speed is relatively low, because of the difficulties noted above, in the simple

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to supply and forward the flowing medium to hydrostatic extrusion presses.

The invention aims to improve the hydrostatic extrusion process by using special equipment and processes to improve, which simplify the operation very considerably beyond that which has been used up to now Practice of professionals was carried out.

The method and the associated device-like features according to the invention consist in the following: the ingot is Provided in advance with one or more coatings, which are made up of two different lubricant systems intended for this purpose come. Each of the lubrication systems can supply one substance or a few per system caused by substances fed in together, which have the intended mode of action in each case. One with a solid lubricant (solid-lubrication) working, assigned to the ingot System works primarily as a lubricant for the extrusion mold or the extrusion die. One with Liquid-lubrication system superimposes its effect on the solid-state lubricant system and works primarily as a lubricant for the recipient, i.e. in the same way as the hydrostatic one flowing medium in the simple hydrostatic extrusion or in the one working with increased bar feed hydrostatic extrusion works. The layer of liquid lubricant is sealed by advancing a Piston pressurized. The presence of a thin, pressurized lubricating fluid existing film between the bar and the wall of the recipient or the extrusion cylinder sets the friction on the wall during the extrusion of the billet down or even practically eliminates them. The radial

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The space between the ingot and the recipient is preferably kept to the minimum size that is required is, through the presence of a thin, pressurized liquid film, the friction on the wall of the recipient or cylinder even more to a minimum. Also, only a minimal amount of liquid lubricant is used between the ingot and the piston at the start of the pressing process applied to the possibility of ensure that sufficient fluid pressure is generated prior to extrusion and that friction is kept to a minimum will. By reducing the volume of liquid lubricant to a minimum, one can use the. '. Ingots by means of of the method and the device according to the invention provided in advance with a coating in various ways. This passing by the ingot increases to a high degree with the help of the medium, which practically creates a hydrostatic flow Mass the production output or speed of the hydrostatic extrusion process, as / it is usually otherwise is exercised according to the state of the art.

Another essential feature of the invention is that the piston is given the opportunity to touch the billet shortly before and during the extrusion process. These The mode of operation is similar to that of the hydrostatic extrusion process with increased billet feed. As a result of that the radial gap between the ingot and the recipient is reduced to a minimum and the appropriate one Lubrication system training and appropriate training using extrusion tools, it is possible to take advantage of hydrostatic extrusion with increased billet feed to achieve without the otherwise this procedure

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accompanying disadvantages of complicated and expensive equipment occur. The radial gap preferably used according to the invention depends to a certain extent on the size of the ingot. For bars with diameters between 25 | 4 mm and 101.6 mm, the gap can be approximately 0.254 mm. Smaller billet diameters can have a gap of less than 0.254 mm down to one . Apply a minimum gap of a few tause / now. With the exception of these smaller ingots, this gap is usually less than Λ% of the nominal diameter of the ingot. According to the invention, the bar may be compressed, but not excessively compressed, because of the small space then used. The use of a lubricant system with a low volume of lubricant also makes it unnecessary to draw off liquid lubricant during the extrusion of the billet, as is disclosed in relation to the prior art in US Pat Ingot feed relates.

Below is a preferred embodiment of the device and the method according to the invention with reference to the drawing for example described, namely shows

the single drawing, designated as FIG. 1, in a semi-schematic representation, a cross section by an extruder, with two lubrication systems for inside the annular Grease introduced between the bar and the recipient lubricant are shown.

The drawing shows an extrusion device that has a Ingot 10 within a recipient or cylinder 20

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which has a piston or punch 30 arranged in such a way that it can press the ingot 10 through a mouthpiece 21. The piston 30 has a seal 31 _f which is arranged and designed in such a way that it either completely prevents any liquid lubricant 22 or solid lubricant 23 from entering the front face of the piston 30 or minimizes this process when the piston is within the Recipient 20 is advanced. The ingot 10 is "lubricated" by two lubrication systems, namely a system for the supply of liquid lubricant 22 and a system for / application of a solid lubricant 23. These lubricants can consist of different materials, such as fluorine-containing plastics on the one hand and castor oil on the other , or they can consist of one and the same material, for example wax in solid form, a layer of this wax, which is adjacent to the recipient 20, being heated by the heating elements 40 in such a way that it forms a film of liquid lubricant 22.

It is the task and mode of action of the solid-state lubricant 23 that it remains essentially on the surface 14 of the ingot 10 and the. Lubrication where the Metal deformation creates the possibility of contact between the bar and the wall of the recipient. It is known, that such contact often occurs in the places where the metal deformation is particularly pronounced and on which the ingot has the tendency to be compressed. The ver-OUiIgUi Section 26 of the extrusion mold'des recipient 20 and the mouth parts 21 are two such areas where

ofnhr exists. One of the tasks of the solid-state lubricant c 23 makes it easier to touch in poor areas et ^ ti! «The presence of the solid-state

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Lubricant 23 along the entire surface 14 of the ingot 10 also provides direct metal-to-metal contact in any area of the recipient wall 28 or reduces the risk of contact to a minimum. It also becomes the normal property of the solid-state lubricant 23, Metal-to-metal contact in common extrusion processes to prevent, reinforced according to the invention in that the liquid lubricant 22 is present, which within the between the recipient surface 28 and the annulus formed in the solid lubricant 23 is highly pressurized.

The layer consisting of liquid lubricant 22 primarily has the task and mode of action, which along the Wall 28 of the recipient reduce friction occurring. Furthermore, the liquid lubricant contributes to the fact that there is a space between the tapered front or nose part of the ingot and the entry surface of the extrusion die, contributing to that within the tapered portion to reduce friction occurring in the extrusion mold. The lubrication caused by the liquid lubricant 22 The wall 28 of the recipient makes it possible for the otherwise normally exhausted and lost to overcoming friction Now exert energy on the parallel bars. The elimination of this friction on the wall of the recipient also creates the possibility of increasing the ratio of the length of the bar to its diameter without the need to -the to substantially increase the force exerted on the parallel bars.

The liquid lubricant also serves to transfer the high pressure that is created when the cavity volume of the recipient is decreased by advancing the sealed piston 30. This pressure can be adjusted by that one changes the amount of liquid lubricant that

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initially present inside the recipient, if required, with high pressures of the liquid lubricant To work, a free space is left between the ingot 10 and the piston 30 between their end faces at 13 and introduces an excess of liquid lubricant into this space before the extrusion process begins. When the ingot 10 is pressed into the extrusion mold 26 and the mouthpiece opening closes practically and effectively, so the pressure prevailing in said liquid layer increases during and in the same mass as the cavity volume of the recipient decreases. If the mentioned excess of volume, of the flowing medium or liquid lubricant is large, the punch 30 does not contact the ingot 10 at 13 before or before the extrusion process takes place it is advanced or while it is going on. The present invention is usually carried out in the foregoing Way is not exercised and the initiation of the extrusion process is usually effected when the forward

striding piston 30 has compressed the liquid lubricant 22 to such an extent that the piston 30 and the Ingots 10 are in contact with one another and the advancement of the ingot 10 is due to that exerted at 13 by the piston 30 Printing takes place. The initiation and effect of the extrusion of the billet by striking or contact with the piston has the additional advantage of eliminating temporary high pressure peaks or keeping them to a minimum, which would otherwise .at the start of a hydrostatic extrusion process result when the lubrication in the area of the extrusion mold is only present at the edge of the ingot or is low or is insufficient. There is a possibility that at some point in the extrusion process the change in The cavity volume of the recipient has become so large that

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the pressure in the liquid lubricant 22 is equal to the pressure exerted by the piston 30, and that at this point is between the ingot 10 and the piston 30 at 13 a film of liquid lubricant 22 forms. This process may not always occur. He means In any case, however, no difficulty, since the ingot is advanced within the recipient in essentially the same way becomes as if it were in contact with the face of the piston at 13. "Plunger" or "piston face" is not intended to be construed narrowly and is not intended to limit the invention, i.e. that of the The scope of protection also extends to the use of technical and patent law equivalents. The seal 31 can also be designed in the form of a dummy block (stuffing box), such a sealing block the ingot 10 touches at 13. YES, it is also a matter of will and ability of those skilled in the art of metal extrusion to adjust the pressure of the liquid lubricant created during the operation or to change it without having to make too many attempts.

The present invention provides the advantage that the extrusion of the billet with substantially constant Extrusion pressure takes place, which is practically independent of the ratio of the length to the diameter of the ingot. Usual Extrusion processes start the operation with a maximum force when initiating the extrusion process, this force being proportional to the length of the not yet during the further course of the operation. extruded part of the ingot decreases. This gradual decrease in extrusion pressure is due to the usual processes ensure that the friction on the wall of the recipient

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decreases to the extent that the not yet extruded part the bar becomes shorter. The invention eliminates this friction on the recipient practically completely or almost and allows ^ that the ingots with a larger ratio of length to diameter are extruded with considerably lower pressures or squeezed out than they are used and are to be used in the usual methods and devices »The Conventional devices and methods for extrusion are indeed economical and result in good quality extrusions; but they are generally limited to extrusion of a bar whose ratio of length to diameter = diameter is less than about 3. However, if the ratio of Increased length to diameter, the extrusion pressure must also be increased and the advantage of a large and good production output when using longer bars to a large extent or completely canceled by the fact that an increased press output is required in order to carry out the extrusion process . .

According to the invention, the previous dependency of the extrusion pressure on the ratio of the length to the diameter of the ingot is removed. When clearing of this dependence, the invention brings with it the possibility _s ingot in a range of, greater ratios of the length to the diameter stranßzvL'pressen and thereby the output speed of a predetermined bzw- extruder to increase.

The invention can be performed in various designs and Ausi'ührujißnraöglichkeiten and applicable depending on the type used to .Schmiermittels. When the solids, ^r; cbni ermitto] \ ma the liquid lubricant from mutually different iJ.toffZusammensetzungen exist, the method and apparatus in the previously described are

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Way executed. Previously used as a solid lubricant Materials or substances can also be used to carry out the invention; they can be made of a metallic or Metal plating or such a coating on the bar or consist, among other things, of chemical compounds or mixtures or substances adhered to the bar or combinations of such lubricants. Specific Examples of useful solid lubricating materials include or consist of the following substances or compositions e.g. from these: copper coatings or plating, zinc phosphate and stearate soap and fluorine-containing plastics. It is true that these materials have given adequate lubricating properties when they are equally touched under high pressure. The invention however, it is not intended to be limited to the application of these materials, since any solids which have lubricating properties own, are applicable.

The liquid lubricant which adheres to the wall of the recipient can consist of a suitable liquid which is compatible with a solid lubricant and the material of the recipient. The method and apparatus according to of the invention were successful with common petroleum oils, vegetable oils, synthetic flowing media or liquids and water. A modification of this process can be to apply a coating of a tough, solid lubricant on the bar, made of a material that can withstand high temperatures. Before start In the extrusion process, a solid lubricant that melts at elevated temperatures is applied as a coating on the Applied to the inside of the recipient. The ingot is heated to a temperature sufficient to coat the lubricant to melt on the wall of the recipient. After introducing the hot and provided with a coating

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Barrens in the recipients provided with lubricant on the wall is the lubricant coating on this wall melted by heat transfer from the bar and a film of liquid lubricant on the wall / the. Recipients educated. The sealed piston is then advanced within the recipient or cylinder and the extrusion process carried out. '.

The invention is also in such cases feasible _s in which the solid lubricant and the liquid lubricant out of one and the same material, the viscosity of which is changed by the temperature of the material "The application of the invention in this manner, it brings with it ₉ that the bar (before its introduction into the recipient) is covered with a layer of a material ₉ that is a solid at the temperature of the bar and that the wall of the recipient is heated to a temperature ₉ at which part of the material is in contact with the wall / The material standing in the recipient either melts or / is brought to a considerably lower viscosity, whereby a layer of liquid is formed on this. A second lubricant system is created, as shown in the drawing, in which a single material supplies or represents both lubricants when used. The material used in this manner must, if a solid material, provide adequate lubrication of the billet, particularly as the billet passes through the extrusion die and die, preventing or minimizing metal-to-metal contact. Materials, which have the property shown to work in the aforementioned way and to act as a lubricant, are Z = B, or hydrogenated vegetable oils contained,

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_ 14 -

heavy petroleum products, waxes and ice.

The materials to be used as lubricants according to the invention are not limited to the above examples, but can be any materials as appropriate Lubricating properties both in the solid state and in the have a liquid state and work in the desired manner, only with the proviso that the temperature at which the state of the lubricant from the solid state to the liquid state changes in a usable state Area lies. The use of materials in which such a change in the physical state does not take place, but a constant change in viscosity takes place when the temperature rises, is also possible according to the invention, only with the restriction to those lubricants whose vis-, The viscosity changes with a change in temperature in such a way that the lubricant changes from a solid state to a lesser state Pass over viscosity, which has approximately the properties of a liquid.

The right temperatures for heating the recipient or the ingot or for the formation of a liquid lubricant layer depend on the material used for the lubricants: through simple testing by a specialist one can easily determine the optimal temperature for any given procedure.

It goes without saying that the use of the terms "liquid" or "liquid ¹ 'and" solid "is intended to denote those properties which are present under actual extrusion conditions and not those at ambient temperature and at atmospheric pressure.

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Of course, the term used above is intended to "Recipient 20" or "cylinder 20" also encompass the extruded part 26, regardless of whether this section with the wall 28 of the recipient is directly related or not or is an independent part. Therefore, if indicated above was that "the recipient 20 - or the wall of the recipient or cylinder 20 - is heated", is thus also This means that the extrusion die section 26 and the extrusion nozzle 21 are also heated.

Furthermore, it goes without saying for the person skilled in the art that he is within the scope of the disclosed inventive concept and the scope of protection of the claims or the invention, modifications of the individually disclosed embodiments of the invention Can make method and the inventive device. For example, more than two lubrication systems can be provided, or the product produced need not be a simple rod such as that obtained from a cylindrical billet as shown is shown in the drawing. The specialist in the ■ Within the scope of the inventive concept, its implementation on the manufacture of tubular products or such products adapt that have complicated cross-sections.

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Claims (1)

PW / ~ mr- Batteile Memorial Institute H. August 1972 U.S. Serial No. 172.039 Patent or Protection claims M.! Method of extruding an ingot through an extrusion die through, preferably for hydrostatic or quasi-hydrostatic extrusion, in particular one Metal ingot, and for lubricating the ingot in the extrusion receiver, the working temperature of the receiver - preferably also a piston or piston which is guided in a longitudinally displaceable manner for advancing the / inside the recipient Stamp) adapted lubricant, namely in the one between the bar or piston on the one hand, and the inner wall of the Recipients and / or the extrusion mold or the extrusion mouthpiece ^ f ^ Ä ^ fe ^ n Annular space, characterized that the bar is previously coated with a solid or solid material adhering to it, which is its composition or by its nature when passing dos Barrens through the extrusion mold as a lubricant for the Ingot works; that further in the annular space between the coated billet and the inner wall of the recipient a layer of a liquid, acting as a lubricant material is applied or during the Extrusion process is generated, preventing the solid material and the liquid material from escaping and that the piston or punch is brought into contact with the ingot as it is advanced and pressed out and at the same time the liquid lubricant essentially during and through the advancement of the punch or piston is put under increased pressure. 309808/0 9 85 2. The method according to claim!, Characterized in that as Fe st st off material and as flüasL-ges Material used for lubrication different materials, which differ in their physical State, especially in their physical state or in differ in their viscosity and / or in their chemical composition. 3. The method according to claim 1, characterized by that the solid material and the liquid material have one and the same chemical composition have that furthermore the recipient is heated in such a way that the state or physical state of the with the Wall of the recipient-material in contact changed and thereby the desired layer of liquid lubricant is formed, which is · in In contact with the inner surface of the recipient. 4 «The method according to claim 2 _V, characterized in that for lubrication on the one hand as solid material or solid material one or more metals and / or material or materials in element form and / or organic compounds and / or inorganic compounds and on the other hand as liquid material one or more vegetable Oils and / or petroleum oil and / or inorganic liquid compounds are used » 5. The method according to claim 3 *, characterized in that that as both a solid or solid material and working as a liquid material Lubricating material of one and the same starting composition hydrogenated castor oil and / or one or more heavy petroleum juin fats or oils and / or wax and / or ice is used « ΛΙ A method of extruding and lubricating an ingot while extruding it through an extrusion die through it, according to one of claims 1-5, since d u r c b // g eke η nze refuses to overlay that for the previous one the ingot is a tough solid lubricating material is used that can withstand elevated temperatures; that also for coating the inner surface of the extrusion receptacle a second solid or solid lubricant is used, which turns into liquid form when heated; that also the ingot on or preferably is heated above that temperature at which the second solid lubricant is converted into a liquid will; that then the heated ingot is inserted into the interior of the recipient and one against the wall of the recipient lying or adhering layer of liquid lubricant from the two-tone solid or Solid lubricant is formed and that the recipient is then inserted by inserting a sealed plunger or piston closed and this is advanced into contact with the ingot. Device, in particular for carrying out the method according to one of claims 1-6 for extrusion of an ingot in an extruder with a recipient or extrusion cylinder together with a longitudinally displaceable, drivable punch or piston, extrusion mold and. mouthpiece and means for applying and / or pressurizing lubricant in an annular space formed between the bar or piston on the one hand and the inner wall of the recipient and / or the extrusion mold or the extrusion mouthpiece on the other hand, characterized in that the means for applying and / or pressurization of lubricant two i lubricant systems are provided in such a way that the one Syatou (23) forms a coating of the ingot made of a solid otter pest body material, which its feed i 0 M ^; ! (ι B - ' UW Ü composition or its nature when passing through the Build by "the extrusion mold as a lubricant for the Ingot works, and the other system (22) in the a ^ ingf a layer of a liquid, material acting as a lubricant forms or. is generated during the extrusion process, and that the piston or plunger (30) in the working position has a closure to prevent lubricant from escaping from it Ringrauiü forms and for pressurizing the lubricant is movable. 8. Apparatus according to claim 7? characterized in that the two lubricant systems (23 and 22) having mutually different lubricants, namely one (23) with a solid material can be fed or produced, and the other nftit a liquid material can be fed or _o to manufacture and can be placed under elevated pressure to give the Different lubricants differ in their physical state _P, in particular in their physical state or in their viscosity and / or in their chemical composition. 9. Apparatus according to claim 7, characterized in that Both lubricant systems (22 and 23) can be fed or produced with one and the same solid material and the recipient (20) can be heated in such a way that the State or aggregate state of the wall of the recipient solid lubricating material in contact changed and the layer (22) in the annular space : is formed from liquid lubricant that comes into contact with the inner surface of the resipient, the solid material and the liquid material being and have the same chemical composition « 309808 / 0-9 85 10. The device according to claim 9, characterized in that, preferably on the outside of the recipient (20), a heating device (40) for heating it and for optionally setting the temperature on the surface of its interior to a temperature or melting temperature adapted to the lubricant of the solid lubricant is provided. 11.Vorrichtung according to any one of claims 7-10, characterized in that the measured in the radial direction width of the annular space between the not yet coated or the already coated with the pesticide bar (10) and the inner wall of the recipient (20) is less than 1 % of the nominal diameter of the billet (10) to be extruded or of the diameter of the extrusion cavity of the recipient or its punch (30). 12. Device according to one of claims 7 to 11, characterized in that that of the rear end face of the bar (10) facing end (13) of the ^ stamp r. or piston (30) on or near this end face, on Circumference of the piston and the ram, is provided with a seal or packing (31) that prevents the escape of Prevents lubricant from the annulus surrounding the ingot. The patent attorney: 309808/0985