Method and device for producing feedstock in piece form from metal

Abstract

The disclosure relates to a method for producing feedstock in piece form from metal, in particular aluminium and/or aluminium alloys, for a metal-casting installation, in particular aluminium-casting installation, in which scrap parts of metal, in particular of aluminium and/or aluminium alloys, are sorted on the basis of their alloying constituents and/or alloy contents and subsequently, on the basis of an alloy to be produced in the feedstock, the scrap parts are mixed into a composition having a homogeneous distribution of the alloy and fed to a press, in which the scrap parts of the composition are subjected to a pressure that compresses the scrap parts while generating a temperature, wherein, as a result of the application of pressure, the scrap parts are heated up to the transition temperature between solid and liquid of at least some of the scrap parts and/or the alloys and/or alloying constituents thereof before the feedstock is discharged in a specific geometrical form.

Claims

1. A method for producing feedstock in piece form made from metal for a metal casting installation, in which method scrap parts made of metal are sorted according to alloy components and/or alloy contents thereof and afterwards the scrap parts are mixed, based upon an alloy to be produced in the feedstock, to form a composition comprising a homogenous alloy distribution and supplied to an extruder in which a pressure is applied to the scrap parts of the composition, which pressure compacts the scrap parts and generates an increase in temperature, wherein the pressure application is of a magnitude such that the scrap parts are heated up to a temperature that corresponds to a melting point of at least a part of the scrap parts and/or the alloy contents and/or the alloy components thereof without an external heat application, before the feedstock having a particular geometric form is output from the extruder.

2. The method according to claim 1 wherein the scrap parts are crushed before being sorted.

3. The method according to claim 2, wherein before the crushing the scrap parts are combined according to the alloy to be produced in the feedstock and supplied to a crushing device.

4. The method according to claim 1, wherein individual fractions of the scrap parts comprising a known composition are taken out of a stocking device as required for the alloy to be produced in the feedstock and are supplied to a mixing device.

5. The method according to claim 1, wherein the feedstock is output as a continuous rope material and cut to length according to needs.

6. The method according to claim 1, wherein metal parts including chips, dust, and melting residuals from the production of metal parts will be used as scrap parts.

7. A device for producing feedstock in piece form made from metal according to the method of claim 1, comprising a storing device comprising several storing areas for storing scrap parts made of metal sorted according to their alloy components and/or alloy contents, a mixing device, in which the scrap parts taken out of the storing areas in a predetermined proportion are mixed to form a composition comprising a homogenous alloy distribution for obtaining an alloy to be produced in the feedstock, and the extruder.

8. The device according to claim 7, wherein a crushing device is arranged downstream of the storing device.

9. The device according to claim 7, wherein the extruder is configured as a screw extruder.

10. The device according to claim 7, wherein the extruder is configured as a piston extruder.

11. The device according to claim 7, wherein the mixing device is arranged upstream of the extruder, wherein individual fractions of the scrap parts taken out of the storage device and comprising a known composition as required for the alloy to be produced in the feedstock are supplied to the mixing device.

12. The device according to claim 7, wherein a cutting device is arranged downstream of the extruder, by means of which cutting device the feedstock output as continuous rope material is cut to length according to needs.

13. The device according to claim 7, wherein a measuring device is arranged downstream of the extruder.

Description

DETAILED DESCRIPTION

(1) Example embodiments will now be described more fully with reference to the accompanying drawing.

(2) The device comprises several storing areas 2 in which scrap parts made of aluminium or aluminium alloys comprising different configurations with respect to the composition and/or the geometric form and/or the size are stored. A continuous conveyor 3 is arranged above the storing areas 2, which continuous conveyor 3 comprises a displaceable continuous conveyor 4, the position of which with respect to the continuous conveyor 3 can be adjusted, such that the individual storing areas 2 can be filled with scrap parts via the continuous conveyor 3 and the continuous conveyor 4.

(3) Another continuous conveyor 5 is arranged beneath the storing areas 2. Each storing area 2 comprises a safety slide 6 on the side of the exit. The safety slides 6 of the storing areas 2 can be opened and closed via a no further represented control, wherein a certain quantity of the different scrap parts stored in the individual storing areas 2 will be transferred onto the continuous conveyor 5 during the opening period.

(4) In addition, a no further represented weighing device can be provided, which is placed between the safety slide 6 and the continuous conveyor 5, such that the quantity of scrap parts comprising a particular composition, i.e. alloy, which is to be transferred onto the continuous conveyor 5 will be weighed, in order to be united with scrap parts from the other storing areas 2, such that the scrap parts conveyed by the continuous conveyor 5 will form a feedstock which comprises a predetermined alloy.

(5) The continuous conveyor 5 transports the scrap parts from the storing areas 2 into a crushing device 7, which comprises two rotating rollers 8 with rabbet ledges that are optionally arranged on these ones. The distance between the rollers 8 or the rabbet ledges that are arranged thereon, but are not represented can be adjusted, such that scrap parts having a particular geometric design and size can be produced by means of the crushing device 7. The scrap parts that pass through the crushing device 7 get then on a sieve device 9 arranged beneath the crushing device 7, which sieve device 9 separates the crushed scrap parts into at least two size fractions, namely into a so-called undersize grain material which passes through the sieve device 9 and an oversize grain material that does not pass through the sieve device 9 and is supplied by the sieve device 9 to a storage container 10. The oversize grain material can be removed by a continuous conveyor 11 from this storage container 10 and for example be transferred onto the continuous conveyor 3 for a new supply to the storing area 2.

(6) The undersize grain material, which passes through the sieve device 9, can be supplied to different bins 13 via a pivoting chute 12, in which bins the undersize grain material of the scrap parts is stored. Herein, different qualities of the scrap parts, namely with respect to their alloy composition and/or with respect to the quantities of the alloy components, are stored in the individual bins 13.

(7) Different fractions of the scrap parts can thus be taken out of the bins 13 and be supplied to a mixing device 14. Such a mixing device 14 can be for example a shaking tub. But it is also possible that such a mixing device 14 comprises mixing tools, such as for example screws which serve to homogenize the different fractions of scrap parts from the bins 13 in the mixing device 14.

(8) As soon as the mixing operation in the mixing device 14 is completed, the mixing device 14 transfers the composition of different batches of scrap parts to another continuous conveyor 15 which supplies the composition of scrap parts to a pressing device 16, namely a screw extruder. The supply takes place in a dosed manner such that the pressing device 16 is constantly filled with a predetermined quantity of scrap parts. Preferably, the supply to the screw extruder is realized in a continuous manner, but at least in such a way that rope material 17 can be continuously output of the exit of the screw extruder.

(9) The supplied scrap parts are compressed in the screw extruder and thus heated up to a temperature, which corresponds to the transition temperature between solid and liquid of at least a part of the scrap parts. On the threshold of the transition temperature the so-called thixotropic state of the heated scrap parts is achieved, which causes a fluidity due to a reduced viscosity. The thus heated scrap parts are pressed through the matrix belonging to the extruder on the end side, such that a continuous output of rope material 17 is obtained. Afterwards, the rope material 17 is cut to length according to the needs by means of a cutting device 18 and then stacked as feedstock 1 on for example a pallet 19.

(10) The use of an extruder is preferable for extruding material having a high viscosity, such as for example aluminium. For this purpose, a special configuration of the extruder screw in combination with a special configuration of the extrusion chamber is provided, in order to limit the rotating flow of the metal. Thanks to this configuration the required compression and extrusion pressure is obtained. During the extrusion of aluminium scrap this one reaches a temperature in the extruder, at which the aluminium scrap sticks together, but also adheres to the walling of the extruder or of the extruder screw. In the following the aluminium scrap will be kneaded and thus reaches a higher temperature, wherein then a plug made of solid material will be formed at the end of the extruder screw, which material will be pushed by following material into an extrusion chamber. The aluminium scrap then leaves the extrusion chamber as continuous rope material and can be cut to length in the form of needs-based feedstock 1, for example in the form of ingots.

(11) The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are inter-changeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.