DEVICE AND METHOD FOR THE PLASTIC FORMING OF A WORKPIECE MADE OF METAL OR A METAL ALLOY BY MEANS OF ECAP

Abstract

A device for the plastic forming of a workpiece made of metal or a metal alloy by ECAP is described. The device comprises more than two channels, wherein an inlet channel and an outlet channel are provided, wherein these channels indirectly connect to one another and are arranged approximately perpendicularly to one another. Furthermore, a method for the plastic forming of a workpiece made of metal or a metal alloy ECAP is described. The workpiece is pressed once or multiple limes through a device having more than two channels, wherein the workpiece is plastically formed by a single or multiple pressing through an inlet channel and an outlet channel which indirectly connects to the inlet channel and is arranged approximately perpendicularly thereto.

Claims

1. A device for the plastic forming of a workpiece made of metal or a metal alloy by means of ECAP, which device comprises more than two channels, characterized in that an inlet channel and an outlet channel are provided, wherein these channels indirectly connect to one another and are arranged approximately perpendicularly to one another.

2. The device according to claim 1, characterized in that at least one additional channel is provided, wherein the inlet channel and the outlet channel are connected to one another by the at least one additional channel.

3. The device according to claim 1, characterized in that each two channels are arranged relative to one another such that they form a forming bend.

4. The device according to claim 1, characterized in that a heating apparatus is provided.

5. A method for the plastic forming of a workpiece made of metal or a metal alloy by ECAP, wherein the workpiece is pressed once or multiple times through a device having more than two channels, in particular through a device according to claim 1, characterized in that the workpiece is plastically formed by a single or multiple pressing through an inlet channel and an outlet channel which indirectly connects to the inlet channel and is arranged approximately perpendicularly thereto.

6. The method according to claim 5, characterized in that, before each introduction into the inlet channel, the workpiece is rotated about a longitudinal axis of the same.

7. The method according to claim 5, characterized in that the workpiece is formed at least twice each time it is pressed through the device.

8. The method according to claim 5, characterized in that the workpiece is pressed through multiple channels, wherein a forming bend is provided between each two channels.

9. The method according to claim 5, characterized in that the workpiece is heated, wherein a temperature is lowered each time the workpiece is pressed through the device.

Description

[0020] Additional features, advantages and effects of the invention follow from the exemplary embodiment described below. In the drawings which are thereby referenced:

[0021] FIG. 1 shows a device according to the invention;

[0022] FIG. 2 shows experimental results of a tensile test;

[0023] FIG. 3 shows experimental results of a compression test;

[0024] FIG. 4 shows additional experimental results of a tensile test;

[0025] FIG. 5 shows additional experimental results of a compression test;

[0026] FIG. 6 shows experimental results of high strengths.

[0027] FIG. 1 shows a device 1 according to the invention for the plastic forming of a workpiece made of metal or a metal alloy by means of ECAP. The device 1 comprises an inlet channel 2 and an outlet channel 3, wherein the inlet channel 2 and the outlet channel 3 are connected by an additional channel 4. The inlet channel 2 and the outlet channel 3, or the longitudinal axes thereof, are arranged approximately perpendicularly to one another. Between the inlet channel 2 and the additional channel 4, a forming bend with an angle a of approximately 90 is provided, Furthermore, between the additional channel 4 and the outlet channel 3, another forming bend is embodied, wherein this forming bend has an angle of approximately 120. The device 1 is thus embodied as a double ECAP device.

[0028] In general, it can also be beneficial if multiple additional channels 4 are provided between the inlet channel 2 and the outlet channel 3, wherein a forming bend is embodied between each two channels 2, 3, 4.

[0029] In FIGS. 2 and 3, experimental results of a tensile test and a compression test are shown. Data A for a workpiece in a starting condition, data B for a workpiece formed using a known ECAP device, and data C for a workpiece formed using the device 1 according to the invention are thereby compared with one another. The workpiece is made of a magnesium alloy and, for data B and data C, is in each case pressed multiple times through a known device and a device 1 according to the invention, respectively. Both the tensile test according to FIG. 2 and also the compression test according to FIG. 3 show that the workpiece produced using the device 1 according to the invention exhibits a significantly higher strength. The workpiece is heated during both the pressing through the known device and also through the device 1 according to the invention, wherein a temperature is lowered from 350 C. to 290 C. between a first pressing-through of the workpiece and a last pressing-through of the same.

[0030] Analogous data A, B and C are shown in FIGS. 4 and 5, wherein a workpiece made of a magnesium alloy is once again formed and measured. However, the magnesium alloy differs in its composition from the magnesium alloy according to FIGS. 2 and 3. It is thereby also evident that the workpiece plastically formed using the device 1 according to the invention exhibits a significantly higher strength than a workpiece produced using an ECAP device having two channels. In this case, a temperature is lowered from 300 C. to 220 C., wherein the workpiece is once again pressed multiple times through a known device and a device 1 according to the invention. Data A once again originates from the untreated workpiece.

[0031] FIG. 6 shows experimental results of a workpiece 1 made of a magnesium alloy, which workpiece has been produced using a device 1 according to the invention. Extremely high strength levels are achieved. A tensile strength of the workpiece is approximately 468 MPa and an elastic limit of the same is approximately 413 MPa.

[0032] With the device 1 according to the invention and the method according to the invention, a workpiece made of a metal or a metal alloy can be produced in an efficient manner, which workpiece exhibits high strength, adequate ductility, high hardness, a uniform fineness of grain, and a low tendency to form cracks. A workpiece of this type is therefore suitable, for example, for the production of a stent or other medical implants.