DE1752238A1 - Hydrostatic double extrusion - Google Patents

Description

f hydrostatic double extrusion

The invention relates to cold hydrostatic extrusion in two ways .Steps.

JDa.s principle for hydrostatic cold extrusion (extrusion under! I'lüGsiglreitsdruck) has been known for a long time. The method means that a lohiing inserted in a cylinder with a mouthpiece or a nozzle is exposed to all-round liquid pressure and is sprayed out through the 1 / üae Iier as soon as the pressure has a certain value from the material of the ioniings, the diisenform, the reduction etc. o-b han _i :; t.

lien relationship between the liquid pressure ρ and the reduction R is approximately based on the G calibration

ρ = B ₁ + B ₀ In R

' ¹ O = ^{ WiXBGhni-b-bQ area of the 3 blank

¹¹ O.ueruchnittsflüohe of the squeezed 3drink

. and ßp aind constants that depend on the material, the, form of the gö etc, depend.

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BATH ORIGINAL

Usually the blank is cold at the start of extrusion. During extrusion, when the material of reduction R is subjected to a heating takes place, the ρ depends on this reduction or via the above-mentioned relation of the pressure used, one tfenn imagines that the whole formed by the reduction Wär me completely in Extruded material remains, it can easily be shown that in this a temperature T would be reached that of the

"Equation

whereby

T = f follows,

et

Q is the density of the material and

c is the specific heat of the material.

In reality, only a low temperature is reached because a Part of the heat is dissipated. The temperature increase in the extruded material tends to make it soft and tough make, i.e. you get a low breaking strength and high elongation, which is especially true for the materials of interest in this context like steel, copper, aluminum and their alloys is the case.

At the same time with this warming and the following reduction in pestilence However, a different process takes place in the case of the materials which are cold-hardening are. The reduction R gives these materials a cold deformation which, if they would act alone, would give the extruded one Would give material greater strength and hardness.

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With hydrostatic cold extrusion, both processes, cold hardening and heating, take place at the same time. The boundary at which the extruded material transitions from a hard to a soft state (or vice versa) is generally not sharp, but the transition can be gradual. As an example it can be mentioned that extruded copper appears to become soft essentially above p = 13 kb and hard below this value.

The designs refer to aluminum as a pressed material, specifically on extrusion of aluminum wire, in order to obtain a more concrete illustration of the problems and the invention. The ratios however, are with various other materials in consideration of the characteristic properties of these materials applicable.

Aluminum wire is widely used nowadays according to the following Method made: i

Aluminum is continuously cast into a strand that is in one or several steps is rolled to a smaller cross-section and then the final dimension and hardness by drawing receives one or more drawing dies. In its most consistent execution this method is continuous, i.e. the cast workpiece is fed directly to the drawing machine and finally reeled. The method is shown in Fig. 1 and in the description of the figures explained in more detail.

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ORIGINAL

The method has two main advantages:

1. It's a continuous method.

2. Get by the large number of relatively small reductions the end product great hardness and tensile strength.

However, the method also has obvious disadvantages:

1. The blanks must be melted.

2. Many drawing steps are required.

3. The drawing dies are worn out and must be replaced.

4. The speed is relatively slow. In practice, the reel speed is hardly greater than 20 m / sec.

The cold hydrostatic extrusion method has the obvious Advantage that very high reductions can be achieved. R = 10,000 or higher can be used without difficulty for aluminum can be obtained. At the same time, as mentioned, this high reduction results in a relatively soft end product. A disadvantage of the method is that it is discontinuous, but this is of no practical importance if the extruded material is in sufficient Lengths can be obtained. This is always possible with aluminum. With a length of the blank of approx. 1 m and with R = 10,000 an extruded wire length of 10 km, while the currently highest required length in practice hardly 3 km should exceed. The speed of the extruded wire can be made very high. If, for example, the one in the orthotic pressure chamber in Pig. 1 penetrating piston has a speed of 0.025 m / sec

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has what is an achievable value, the extruded wire becomes one Have an exit speed of at least 250 m / sec.

The desirable properties of a hydrostatic manufacturing facility Extrusion can be summarized as follows:

1 . low reduction.

2. The extruded oil material must have great strength at ^ .luiäiiiium-wire at least equal in size to those used in normal Pull, is obtained.

3. Me extrusion speed (production per unit time) must be sufficiently high.

4. Me continuous extruded length must be sufficient.

/ Ig mentioned here the problem is to satisfy point 1 and 2 at the same time · δμ. The invention aims to solve this problem.

An obvious method would be to first carry out a hydrostatic extrusion with a large reduction, then to cool the pressed out material in order to finally cool it down in several steps with little editing, ie wire drawing in the now usual way on aie / inddimensioneh y. \ x to reduce. This method is practically applicable, but is afflicted with the error, among other things, that each material extruded into wire must be drawn through several drawing dies before the final drawing takes place. This is a disadvantage considering the production speed. Welding of the wire

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end up solving this problem, but this too is associated with certain practical difficulties, particularly with regard to the reeling. The method is in Pig. 2 and in connection with this explained.

The invention is characterized in that a blank in two steps to a finished or essentially finished product

"is pressed in such a way that with hydrostatic extrusion of a blank the pressed material is introduced through a nozzle directly into a subsequent nozzle and is pressed hydrostatically through this. The reduction in extrusion through the first nozzle is considerable larger, usually many times larger than the reduction through the subsequent nozzle. The pressure chambers for the two steps are like this arranged that the nozzle for the first pressing step or the holder for this nozzle forms a partition between the chambers. The chambers can be designed as a unit with an inner set

\ , and the nozzle for the first pressing step or the holder for this nozzle can be designed as a piston which is inserted into the unit and supported by the mentioned approach. The nozzle for the second pressing step is movably arranged for this step in the pressure chamber so that it can be pushed directly to the nozzle for the first pressing step before the start of the extrusion, so that the extruded material coming from the first nozzle enters the nozzle for the second Crotch is pressed. Expedient; is the nozzle for the second step or the holder for this like a double-acting one

BATH ORIGINAL

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Piston formed by the pressure fluid between the receiving position at the nozzle for the first pressing step and the working position moved a certain distance away from this.

The pressed strand or wire produced by the deformation of the material is heated in the nozzle, is cooled by the pressure fluid in the pressure chamber for the second pressing step. To receive the chamber is connected to a cooler for uniform cooling. Cooled pressure medium is expediently pressed out of a possibly ring-shaped mouthpiece in the first pressing step Strand or wire straightened.

The known methods indicated for the production of aluminum wire and the arrangement for double extrusion according to the invention are described in more detail below with reference to the drawing, in which Drawing show:

Fig. 1 shows a method for continuously making wire from

a melt,
2 shows the production of wire in conventional hydrostatic cold extrusion with subsequent drawing of the workpiece obtained to the correct dimension and hardness by drawing

stones,
Fig. 3 and 4 the production of wire with the correct dimension

and hardness by double extrusion according to the invention and Pig, 5 a variation of the pressure chamber.

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In Pig. 1, 1 denotes a casting machine for a conventional casting of a bar 2 which is rolled into a wire 4 in a rolling mill 3 which is drawn out in drawing machines with drawing dies 5 and 6 to form a wire 7 of the desired dimension and hardness. The wire will then wound onto a reel 8. In Fig. 2, 11 is a pressure chamber, 12 a nozzle arranged in this and 13 a movable piston. The cylinder and piston are in a press frame, not shown arranged. 14 and 15 denote seals between the cylinder and the nozzle or piston. The nozzle 12, which also has one wall in the pressure chamber forms, rests on a press table 25. The blank 16 is surrounded by a pressure medium 17. With the downward one Movement of the piston 13 generates a pressure in the pressure chamber, which presses out the material in the blank 6 through the mouthpiece 12, so that a wire 18 is formed. This intermediate product is wound onto a reel 19, transferred to a reel 20 and passed through a number of drawing dies 21, 22, 23 drawn to the correct dimension and hardness, after which it is wound onto a reel 24.

In Pig. 3 and 4, 30 is a cylinder, 31 is a wall into which a nozzle 32 is inserted, 33 a piston which is arranged in a press frame, not shown, 34 are seals between the cylinder 30 and piston 33 or the wall 31 * 35 is a blank and 36 a pressure medium which completely fills the space between the blank 35, cylinder 30, piston 33 and wall 31. Right under the cylinder 30 a cylinder 37 is arranged. The wall 31 in the cylinder 30 forms

-9 ~ BATH ORIGINAL

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also an end wall in this cylinder. The other end wall is made from a cover 33. 39 is a seal between the cylinder 37 and the ./and 31 or the cover 38. The cylinder 37 is with formed exnem annular projection 40, which is against a table

41 is supported in the press frame mentioned and not shown. An axially movable piston 42 with a nozzle 43 and a hollow shaft 44, which is guided through the cover 38, is arranged in the cylinder 37. 45 are seals between the cylinder 37 and piston 42, or between the cover 38 and shaft 44. The space 46 above the piston

42 and the lumen 47 under the piston 42 are filled with compressed air and are in communication with valves 50 and 51> via lines 48 and 49, respectively by soft the movements of the piston 42 by means of

ik pressure medium can be controlled by a hydraulic system (not shown in the figures). The lumen 46 is also connected to a cooler 55 via lines 52 and 53 and a circulation pump 54. 56 denotes material (wire) pressed through the mouthpiece 32 and 57 through the mouthpiece 43 and 53 a reel for winding up the material (wire).

In the embodiment according to FIG. 5, the pressure chambers for both the orsten and the second extrusion step are arranged in a single cylinder CO. The wall between the chambers in which the ⁷ IULLdDtUG /. 32 is mounted for the first Presschritt, a piston 61 which _t is in a ringfürmi; .en projection 62 rests in the cylinder 60th 63 is a seal that seals between the cylinder 6o and piston 61

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o- ·: 'GSNAL

tet. Otherwise the arrangement is the same as in Pig. 3 and 4 shown match.

The arrangement according to the invention works as follows:

The chamber in cylinder 30, the primary chamber, is made with a blank 35 loaded, and the piston 42 is guided into its upper position shown in FIG. 3, in the pressure medium the space 47 via the valve 51 and the line 49 is fed so that the upper part of the piston rests directly on the ./and 31 in which the nozzle 32, the primary nozzle, is arranged. The piston 33 is inserted into the cylinder 30 and creates a pressure in the one enclosed in the primary chamber Pressure medium 36, which thereby extrudes the material in the blank 35 through the nozzle 34. The extruded rod or wire 56 is pushed directly against the mouthpiece 43. At the same time, the space 46, the secondary karamer, is pressurized by the fact that a pressure medium is supplied via the valve 50 and the line 48, the piston 42 is pushed into the position shown in FIG. 4 when the pressure medium in the space 47 through the line 49 and the valve 51 can flow out. The pressure in space 46 is given such a value that the same amount of material always passes through nozzle 43 »the secondary nozzle, as is pressed through nozzle 32, the primary nozzle. The rod 56 pressed by the nozzle 32 is thereby substantially just when the pressure in space 46, the secondary chamber, increases is low, the rod 56 is kinked, curls itself into the se-

ORIGINAL BATHROOM -11-

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secondary chamber and forms a coil, making an extrusion through the secondary nozzle 43 is impossible. Pressed through the secondary nozzle Material, e.g. 3. Wire, is wound on a reel 53.

The distance between the primary nozzle 32 and the secondary nozzle 43 becomes like this chosen large that the rod 56 on one for extrusion in the Secondary nozzle 45 is cooled appropriate starting temperature. this usually means that a substantial part of the at the primary Extrusion generated heat must be dissipated. The cooling can be carried out in a variety of ways, for example by the liquid in the space 47, the secondary chamber, through a cooler 55 pumps with a pump 54, as described in Pig. 5, 4 and 5 is shown.

if: i ^: o. wants to have hard material in the finished product, the ! eduction in the second pressing step, i.e. through the dog piece 43 "small and the blank 56 is effectively cooled before it reaches the mouthpiece 43. This allows the temperature at the secondary Extrusion can be kept so low that the cold deformation effect predominates in this step.

By the invention it is achieved that one also with hydrostatic Cold extrusion, within wide limits, the hardness and strength of the finished product, be it wire, rods or profiles, can vary.

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BATH

The invention is of course not limited to that shown in the figures Limited versions, but can be varied in many ways within the scope of the claims.

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Claims (1)

Patent claims: 1. Arrangement for hydrostatic cold extrusion of a blank by a nozzle, characterized in that the extruded strand or wire is introduced directly into a subsequent nozzle (43) and is pressed hydrostatically through this. 2. Arrangement according to claim 1, characterized in that the reduction When pressing through the first nozzle (32), it is considerably larger (7th times larger) than the reduction when pressing through the following Nozzle (43). 3. Arrangement according to claim 1 or 2, characterized in that the nozzle (32) for the first pressing step or the holder (31) for Ciie ^ o nozzle forms a partition between the two pressure chambers (30, 37). 4. Arrangement according to claim 3, characterized in that the pressure chambers for the first and the second pressing step as a unit (60) are designed with an inner extension (62), and that the nozzle (32) for the first pressing step or the holder for this nozzle is designed as a piston (61) which is supported by the extension (62). b. Arrangement according to one or more of the preceding claims, characterized in that the nozzle (43) for the second pressing 109820/0595 _r! , _r , ^ ■ - "- ,,,,," ~ ¹⁴ ~ step axially movable in the pressure chamber (37) for this step is arranged. 6. Arrangement according to claim 5, characterized in that the nozzle (43) for the second pressing step or the holder for this The nozzle is designed as a double-acting piston (42). 7. Arrangement according to claim 5 or 6, characterized in that the nozzle (43) for the second pressing step or the holder for this Nozzle is arranged so that it (he) can be pressed against the nozzle (32) for the first pressing step, so that at the beginning of the Pressing the material from the nozzle in the first pressing step is pushed directly into the nozzle in the second step. 8. Arrangement according to one or more of the preceding addresses, characterized in that the pressure chamber (37) for the second pressing step is connected to a cooler (55). 9. Arrangement according to claim 3, characterized in that the cooled Pressure medium is directed through a mouthpiece against the material pressed out through the nozzle in the first pressing step. 109820/0595 Emptied