Pouring device for casting a melt, and a method for casting a melt

Description

[0001] The invention relates to a casting device for casting a melt, as well as a method for casting a melt.

[0002] Electromagnetic pumps for conveying a melt between a melting furnace and a casting mold are known from EP1097013B1 and WO2019 204845 A1.

[0003] The design of EP1097013B1 has the disadvantage that the electromagnetic pump has a poor effectiveness, especially with paramagnetic materials such as aluminum.

[0004] The object of the present invention was to overcome the disadvantages of the prior art and to provide a method and a device by means of which paramagnetic materials can also be transported.

[0005] This object is achieved by a device and a method according to independent claims 1 and 12, respectively. Further embodiments are described in the corresponding dependent claims 2-11 and 13-18, respectively.

[0006] The casting device according to the invention has the advantage that the quality of the casting process can be improved.

[0007] Furthermore, it may be advantageous for the magnetic element to be designed as an electromagnet. An electromagnet offers the advantage that the magnetic field can be applied selectively.

[0008] It is provided that at least one first heating element is arranged in the region of the first electrode and at least one second heating element is arranged in the region of the second electrode. This has the advantage that excessive cooling of the melt in the region of the electrodes can be prevented by the heating elements, whereby solidification and / or cooling of the melt in the region of the electrodes can be prevented. This can be particularly necessary if a material with high thermal conductivity is used for the electrodes. Especially with such a configuration, heat is quickly dissipated from the melt, which creates the risk of local solidification and / or cooling of the melt in the region of the electrodes.

[0009] Furthermore, the melt can be maintained at a certain melt level in the riser tube between individual casting processes, particularly during the removal of a cast workpiece, without the melt flowing in the riser tube. The measures according to the invention ensure that the melt does not solidify in the area of ​​the electrodes.

[0010] Furthermore, it can be provided that the first heating element and the second heating element are each designed in the form of a resistance heating element, in particular with a ceramic heating conductor. This offers the advantage that a heating element designed in this way can be easily heated as needed, and, moreover, a sufficiently high temperature can be achieved to heat the electrodes. In particular, resistance heating elements with a ceramic heating conductor can be heated quickly to a high temperature.

[0011] Furthermore, it can be provided that two of the first heating elements are arranged on opposite sides of the cross-section of the first electrode. This has the advantage that the electrode can be heated evenly and / or more quickly across its cross-section.

[0012] Furthermore, it can be provided that the first electrode has a rectangular cross-section and that two of the first heating elements are arranged on opposite sides of the cross-section of the first electrode. This has the advantage that the electrode can be heated evenly across its cross-section.

[0013] Furthermore, it can be provided that the heating elements are dimensioned in such a way that if one of the two heating elements fails, the second of the heating elements can still provide sufficient heat energy to maintain the required temperature.

[0014] In particular, it can be provided that a machine control system detects a failure of one of the heating elements and automatically heats the remaining heating element(s) beyond normal operation to compensate for the failure of one of the heating elements. The failure of one of the heating elements can be detected, for example, by the lack of power consumption.

[0015] Another advantageous embodiment is one in which one of the first heating elements is arranged on each of the four sides of the rectangular cross-section of the first electrode. This has the advantage that the electrode can be heated evenly across its cross-section.

[0016] According to a further development, it is possible for the electrodes to comprise a graphite material in a first region of the melt contact surfaces. A graphite material has the advantage that it does not oxidize when contacted by an aluminum melt. Furthermore, a graphite material is a good electrical conductor. Furthermore, a graphite material exhibits high temperature resistance.

[0017] In an alternative embodiment, the electrodes may comprise an electrically conductive ceramic material in a first region of the melt contact surfaces. Such a ceramic material offers the advantage of being surprisingly well suited for contacting the melt in the intended application. In particular, the ceramic material exhibits high resistance to deformation, wear, and chemical corrosion. In particular, the ceramic may be manufactured as a sintered component.

[0018] In particular, it can be provided that the electrodes comprise a zirconium carbide material in a first region of the melt contact surfaces. Zirconium carbide is a compound with high chemical variability in the Zr-C ratio. Zirconium carbide exists in a composition range from ZrC1.0 to approximately ZrC0.6. The electrical properties nevertheless remain largely stable. Zirconium carbide differs from other materials in that it is thermally, chemically, and mechanically stable up to extremely high temperatures of 2500 °C.

[0019] Furthermore, it may be advantageous for the electrodes to be made of an austenitic material in a second region facing away from the melt contact surfaces. This has the advantage that an austenitic material exhibits good electrical conductivity while maintaining sufficient temperature resistance. This has the further advantage that the magnetic field is least affected by an austenitic material. Ferritic materials would deflect the magnetic field.

[0020] Furthermore, it can be provided that the heating elements are each arranged in the second region of the electrodes.

[0021] Furthermore, it can be provided that bores are formed in the second region of the first electrode, in which rod-shaped first heating elements are arranged. The use of rod-shaped heating elements inserted into the bores offers the advantage that the electrode can be heated evenly and from the inside out. In particular, the use of the rod-shaped heating elements in the second region of the first electrode can achieve good heat introduction into the electrode.

[0022] Furthermore, it can be provided that bores are formed in the second region of the second electrode, in which rod-shaped first heating elements are arranged.

[0023] In a further development, it can be provided that the bores for the rod-shaped heating elements are introduced into the second region of the electrode starting from the separating surface between the first region of the electrode and the second region of the electrode.

[0024] Furthermore, it can be provided that the heating elements are designed in the form of flat heaters, which can have a rectangular cross-section.

[0025] Furthermore, the magnetic element can comprise a first coil and a second coil, which are arranged on two diametrically opposite sides of the cross-section of the flow connection element. This has the advantage that such an arrangement allows a high magnetic field to be applied to the flow connection element.

[0026] Furthermore, it can be provided that the magnetic element comprises a magnetic core, in particular an iron core, which is C-shaped and arranged in the region of the flow connection element such that the flow connection element is arranged between a first open end of the magnetic core and a second open end of the magnetic core, wherein the first coil surrounds the first open end of the magnetic core and the second coil surrounds the second open end of the magnetic core. This has the advantage that the magnetic core can enhance the magnetic effectiveness of the coils.

[0027] Furthermore, it can be provided that a plurality of flow connection elements are formed which are arranged uniformly distributed around a center, wherein individual magnetic core segments are arranged between the flow connection elements, wherein a magnetic core segment faces a first of the flow connection elements at a first longitudinal end and faces a second of the flow connection elements at a second longitudinal end, wherein the first longitudinal end of the magnetic core segment is surrounded by a first of the individual coils and the second longitudinal end of the magnetic core segment is surrounded by a second of the individual coils. This arrangement of the magnetic core segments can be uniformly distributed around the circumference.In such a structure, it is conceivable that two flow connection elements, three flow connection elements, four flow connection elements, five flow connection elements or a higher number of flow connection elements are arranged evenly distributed around the circumference.

[0028] In a first embodiment, it is conceivable that the individual coils are all supplied with current together in order to generate a magnetic field.

[0029] In another design variant, it is also conceivable for the individual coils to be selectively and independently energized to generate a magnetic field. This has the advantage that the magnetic field can be generated with varying strengths across the air gap.

[0030] According to a particular embodiment, it is possible for the magnetic element to comprise a plurality of individual coils evenly distributed around the cross-section of the flow connection element, with magnetic core segments arranged between the individual coils, each magnetic core segment being surrounded by a first of the individual coils at a first longitudinal end and by a second of the individual coils at a second longitudinal end. Such a configuration offers the advantage of achieving an increased magnetic field effect.

[0031] According to an advantageous development, a cooling device can be provided in the area of ​​the coils. This has the advantage that this measure can prevent the coils from overheating.

[0032] Furthermore, it can be provided that the electrodes are interchangeable.

[0033] Furthermore, it can be provided that a first recess is formed in the flow connection element, which serves to accommodate the first electrode. Furthermore, a second recess can be formed, which serves to accommodate the second electrode.

[0034] Furthermore, it can be provided that the first electrode forms a clearance fit with the first recess, so that the first electrode closes the first recess when inserted into the first recess.

[0035] Furthermore, it can be provided that the second electrode forms a clearance fit with the second recess, so that the second electrode closes the second recess when inserted into the second recess.

[0036] Furthermore, it can be provided that a first positioning element is formed on the first electrode, which serves for the positive positioning of the first electrode in the flow connection element. In particular, it can be provided that the first positioning element serves for axial positioning and thus for determining the position of the first melt contact surface.

[0037] In a first embodiment, the first positioning element can be designed in the form of a shoulder, wherein the first electrode is pushed into the flow connection element until the shoulder rests against a contact surface of the flow connection element. Furthermore, the first electrode can be pressed into the flow connection element by means of a first pressing element, so that the shoulder is pressed against the contact surface of the flow connection element. In particular, the first pressing element can be designed in the form of a spring element.

[0038] Furthermore, it can be provided that a sealing element is arranged on the contact surface or on the shoulder, or that a sealing element is arranged between the contact surface and the shoulder. This has the advantage of achieving an improved seal between the first electrode and the flow connection element.

[0039] Furthermore, it can be provided that a second positioning element is formed on the second electrode, which serves for the positive positioning of the second electrode in the flow connection element. In particular, it can be provided that the second positioning element serves for axial positioning and thus for determining the position of the first melt contact surface.

[0040] In a first embodiment, the second positioning element can be designed in the form of a shoulder, wherein the second electrode is pushed into the flow connection element until the shoulder rests against a contact surface of the flow connection element. Furthermore, the second electrode can be pressed into the flow connection element by means of a second pressing element, so that the shoulder is pressed against the contact surface of the flow connection element. In particular, the second pressing element can be designed in the form of a spring element.

[0041] Furthermore, it can be provided that a sealing element is arranged on the contact surface or on the shoulder, or that a sealing element is arranged between the contact surface and the shoulder. This has the advantage of achieving an improved seal between the second electrode and the flow connection element.

[0042] Furthermore, it can be provided that the first melt contact surface and the second melt contact surface have a surface in the form of a cylinder segment and, in the installed state of the first electrode and the second electrode, continue the inner surface of the flow connection element.

[0043] In an alternative embodiment, the cross-section of the flow connection element can be rectangular, at least in sections, and the two melt contact surfaces can be arranged opposite each other and parallel to each other. This has the advantage that the short-circuit current can flow evenly between the melt contact surfaces. This allows a more uniform magnetic field to be generated in the melt.

[0044] In particular, it can be advantageous if the electrodes are connected to power sources via detachable clamp contacts. This allows the individual electrodes to be easily and conveniently replaced as needed.

[0045] The invention also relates to a method for casting a melt of a metallic material according to independent claim 12.

[0046] The melt of the metallic material is subjected to current by means of a first electrode and a second electrode, which contact the metallic material via melt contact surfaces. At the same time, a magnetic field acts on the area of ​​the melt exposed to current, with the electrodes being heated by heating elements as needed.

[0047] This has the advantage that excessive cooling of the melt in the area of ​​the electrodes can be prevented by the heating elements, thus preventing solidification of the melt in the area of ​​the electrodes. This can be particularly necessary when a material with high thermal conductivity is used for the electrodes. Especially with this type of configuration, heat is quickly dissipated from the melt, creating the risk of local solidification of the melt in the area of ​​the electrodes.

[0048] Furthermore, the electrodes can be heated when the melt flow in the flow connection element is stopped. This has the advantage of preventing local solidification of the melt in the area of ​​the electrodes.

[0049] Furthermore, it is conceivable that the electrodes are not heated if the melt flow in the flow connection element is sufficiently high and constant.

[0050] Furthermore, it can be provided that a casting device is used for casting the melt, which is designed as a low-pressure casting device or as a counter-pressure casting device, wherein the casting device comprises a furnace in which a receiving space is formed for receiving melt, wherein the receiving space is coupled to a casting mold by means of the flow connection element, wherein at the start of the casting process, the pressure in the receiving chamber is increased in order to press the melt through the flow connection element into the casting mold, whereby only when a predefined amount of melt, which has flowed through the flow connection element, is reached, the melt in the flow connection element is subjected to current and at the same time the magnetic field is activated, which acts on the area of ​​the melt subjected to current in order to slow down the melt in the flow connection element.

[0051] This has the advantage that the casting process can be carried out at high speed, thus achieving a short cycle time. At the same time, this measure makes it possible to produce a high-quality cast workpiece which, compared to conventional cast workpieces, can have fewer shrinkage cavities or air inclusions. In particular, by braking the melt using the magnetic field, the melt can be calmed down during casting, thus producing an improved cast workpiece. Surprisingly, it has been shown that an improved casting result can be achieved if the magnetic field or the current applied to the melt are not activated from the beginning of the casting process, but are only activated at a certain point during the casting process.

[0052] Furthermore, it can be provided that the pressure in the receiving chamber is increased such that a constant pressure increase occurs at the inlet of the casting mold, in particular a pressure increase between 16 mbar / s and 45 mbar / s, preferably between 23 mbar / s and 35 mbar / s. Particularly with such a pressure increase, a surprisingly good casting result can be achieved. A deviation of up to 3 mbar / s from a linear pressure increase is also considered a constant pressure increase.

[0053] In particular, the values ​​specified in the above paragraph can relate to a pressure increase in the differential pressure between the receiving space and the mold cavity. For example, if the back pressure in the mold cavity is increased or decreased in a counterpressure casting process, this can be taken into account accordingly to achieve a constant pressure increase.

[0054] Furthermore, it may be advantageous to apply current to the melt in the flow connection element and activate the magnetic field that acts on the current-exposed area of ​​the melt to slow the melt in the flow connection element when a melt surface flows from a gate into a mold cavity. This results in a surprisingly good casting result with few cavities in the inlet area. In particular, it may be provided that current is applied to the melt and the magnetic field is activated simultaneously.

[0055] Furthermore, a computer-implemented simulation model can be used to calculate the pressure increase, activation times, and activation intensities of the magnetic field, as well as the activation times and activation intensities of the current applied to the melt, at which a casting process with as few cavities as possible in the cast workpiece can be achieved. Furthermore, the computer-implemented simulation model can consider a pressure curve for the pressurization in the melt receiving chamber. Furthermore, the simulation model can be limited to the area of ​​the inlet into the casting mold, whereby the flow velocities at the inlet of the flow connection element may not be taken into account.This calculation result can be used to determine the activation times and intensities of the magnetic field, the activation times and intensities of the current applied to the melt, and the pressure curve for the pressurization in the melt receiving chamber. This has the advantage of allowing the ideal casting process to be calculated for different cast workpieces. By calculating this in a computer-implemented simulation model, surprisingly good results can be achieved for the cast workpiece, as a large number of different parameters can be considered compared to a test-based approach, and the time required to obtain different results can be significantly reduced.

[0056] In particular, it can be provided that the computer-implemented simulation model carries out the calculations using an artificial neural network.

[0057] Furthermore, it can be provided that a digital twin of the casting device is created and that the computer-implemented simulation model is adapted during the casting process. In particular, it can be provided that melt properties, such as a melt temperature, are measured and the parameters of the casting process, such as the temporal pressure increase curve and / or the temporal course and intensity of the generation of the magnetic field and / or the temporal course and intensity of the current application to the melt, are adapted depending on the melt properties.

[0058] Furthermore, it can be provided that a change in the current or voltage applied to the coils, or also a change in the current or voltage applied to the electrodes, is detected by the machine control system, and the currents and voltages can be adjusted accordingly by the machine control system. This adjustment can be made based on stored adjustment tables. Alternatively, the adjustment can be made using a neural network.

[0059] Furthermore, the measured currents and voltages can be used to determine the presence of defects. In particular, the recorded currents and voltages, as well as other sensor values, can be incorporated into a simulation of the casting process. This allows conclusions to be drawn about the quality of the cast workpiece. If a quality defect is suspected, a quality inspection of the cast workpiece can be recommended.

[0060] Also advantageous is a form of embodiment according to which it can be provided that a heating process for heating the electrodes is started with a lead time before the melt flow stops or before a minimum flow rate is undershot, wherein the lead time is between 1 second and 600 seconds, in particular between 5 seconds and 120 seconds, preferably between 10 seconds and 60 seconds. This has the advantage that at the time the melt flow stops or at the time the minimum flow rate is undershot, the electrodes can already be sufficiently heated to prevent local solidification of the melt in the area of ​​the electrodes.

[0061] Furthermore, it can be provided that the melt in the flow connection element is subjected to current and the magnetic field is activated, which acts on the area of ​​the melt subjected to current in order to slow the melt in the flow connection element even before a melt level flows from a gate into a mold cavity. During this time, the pressure in the receiving space is increased and the magnetic field is deactivated at a predetermined time. This can achieve that an increased pressure is built up in the receiving space without melt flowing into the mold cavity. The melt can then be allowed to flow into the mold cavity at an increased speed. This results in a shortening of the cycle time.

[0062] In particular, it can be provided that the pressure in the receiving chamber is increased according to the above paragraph while an already cast workpiece is removed from the mold cavity. Subsequently, the magnetic field can be deactivated, at least temporarily, when the mold cavity is closed again.

[0063] In an alternative design variant, it is also conceivable for an air chamber to be coupled to the receiving chamber, particularly in a compressed air supply line upstream of the compressed air supply opening. The air chamber can be used to temporarily store compressed air in order to increase the pressure in the receiving chamber at a higher rate. This allows the melt to flow into the mold cavity at a higher rate. This results in a reduction in the cycle time.

[0064] Furthermore, a control system can be provided that is designed such that the electrodes are continuously heated to a temperature higher than the solidus temperature of the melt. For example, for aluminum, this temperature can be between 550°C and 850°C, in particular between 700°C and 750°C. For example, for AlSi10Mg, the liquidus temperature is 594°C and the solidus temperature is 561°C.

[0065] It is also advantageous to design the heating control of the electrodes based on the solidification time of the component to be cast and the solidification temperature of the melt, so that the temperature of the melt in the area of ​​the electrodes during solidification of the component does not fall below the solidification temperature of the melt, or only partially falls below it. This ensures that no part of the melt partially solidifies during the next casting cycle or during the next component. Furthermore, it can be ensured that the melt transported during filling of the cavity cools less in the area of ​​the electrodes.

[0066] For a better understanding of the invention, it is explained in more detail using the following figures.

[0067] They show in a highly simplified, schematic representation: Fig. 1 shows a first embodiment of a casting device in the form of a low-pressure die casting device or counter-pressure die casting device; Fig. 2 shows a further embodiment of a casting device in the form of a low-pressure die casting device or counter-pressure die casting device; Fig. 3 shows a schematic cross-sectional view of the flow connection element; Fig. 4 shows a sectional view along the section line IV-IV of Fig. 3 ; Fig. 5 a schematic cross-sectional view of the flow connection element of a further embodiment of the casting device; Fig. 6 a sectional view of a further embodiment of the casting device according to the section line IV-IV of Fig. 3 ; Fig. 7 a sectional view of another embodiment of the casting device according to the section line IV-IV of Fig. 3 ; Fig. 8 a diagram of a time course of a filling process of a mold cavity of a casting mold.

[0068] By way of introduction, it should be noted that in the variously described embodiments, identical parts are provided with identical reference symbols or component designations. The disclosures contained throughout the description can be applied analogously to identical parts with identical reference symbols or component designations. Furthermore, the positional information chosen in the description, such as top, bottom, side, etc., refers to the directly described and illustrated figure, and these positional information must be applied analogously to the new position in the event of a change in position.

[0069] Fig. 1 shows a schematic representation of a first embodiment of a casting device 1. The casting device 1 is designed in this embodiment as a low-pressure die casting device or as a counter-pressure die casting device.

[0070] The casting device 1 can comprise a furnace 2, in which a receiving space 3 for receiving melt 4 can be formed. In particular, it can be provided that a crucible 5 is arranged in the furnace 2, in which the melt 4 is received. The crucible 5 can be made of a ceramic material with high temperature resistance. The furnace 2 can serve, in particular, to keep the melt 4 at a high temperature level so that it remains in the molten state.

[0071] Furthermore, a mold clamping plate 6 can be formed, which defines the upper limit of the furnace 2. The mold clamping plate 6 can be formed either as a separate component or as an integral component of the furnace 2. A casting mold 7 can be arranged above the mold clamping plate 6, which has a lower casting mold part 8 and an upper casting mold part 9. The two casting mold parts 8, 9 form a mold cavity 10, which serves to receive the melt 4 and to shape the cast workpiece.

[0072] The casting mold 7 can, for example, be designed in the form of a chill mold, which is suitable for casting several workpieces.

[0073] Alternatively, it is also conceivable that the casting mold 7 is designed as a lost casting mold, such as from a sand material, and thus only serves to cast a single workpiece.

[0074] Furthermore, a flow connection element 11 is formed, which serves to guide the melt 4 from the crucible 5 into the mold cavity 10. In the present exemplary embodiment, the flow connection element 11 is designed as a riser pipe 12, which projects into the receiving space 3 of the furnace 2 and penetrates the mold clamping plate 6. The lower mold part 8 can be directly connected to the riser pipe 12 and have a gate 13 into which the riser pipe 12 opens. Furthermore, a support structure 14 is shown in a highly simplified manner, which can be coupled to the upper mold part 9 and can serve to move the upper mold part 9 relative to the lower mold part 8.

[0075] Furnace 2 may further comprise a compressed air supply opening 15 through which compressed air can be introduced into the receiving chamber 3 of furnace 2. By applying compressed air to the receiving chamber 3 of furnace 2, the melt 4 in the riser tube 12 is forced into the mold cavity 10.

[0076] Furthermore, a magnetic element 16 is formed, which in the present embodiment is arranged in the region of the flow connection element 11. The magnetic element 16 can in the present embodiment comprise an electromagnet 17, which has a coil 18. The coil 18 is designed in this embodiment such that the flow cross-section of the flow connection element 11 is enclosed in a ring-shaped manner by the coil 18. In particular, as can be seen from Fig. 1As can be seen, the coil 18 can be arranged within the furnace 2 and surrounds the riser pipe 12, subjecting it to a magnetic field. Alternatively, the coil 18 can also be integrated into the riser pipe 12. Of course, a permanent magnet can also be provided instead of the coil 18.

[0077] From sectional view II, which represents a cross-section through the flow connection element 11, it can be seen that the magnetic element 16, in the region of the magnetic element 16, on an inner circumferential surface 19 of the riser pipe 12, can comprise a first electrode 20 and a second electrode 21, which are designed to apply current to the melt 4 being transported in the riser pipe 12. By means of the magnetic element 16, a Lorenz force 22 can be exerted on the melt 4 guided in the flow connection element 11. The Lorenz force 22 can act in a conveying direction 23 or counter to the conveying direction 23.

[0078] A first melt contact surface 24 of the first electrode 20 and a second melt contact surface 25 of the second electrode 21 can be integrated into the inner surface 19 of the flow connection element 11 or the gate 13. Thus, the electrodes 20, 21 can be flush with the inner surface 19 of the flow connection element 11 or the gate 13.

[0079] In particular, it is conceivable that the Lorenz force 22 acts as a conveying support for conveying the melt 4 from the crucible 5 into the mold cavity 10.

[0080] Furthermore, it is also conceivable that the Lorenz force 22 serves to brake the melt 4 conveyed in the flow connection element 11.

[0081] In further embodiments, it is also conceivable that the casting device 1 is designed as another type of casting device 1 which has a flow connection element 11.

[0082] In a further embodiment not shown, it is also conceivable that the magnetic element 16 is arranged between the mold clamping plate 6 and the casting mold 7.

[0083] Fig. 2 shows a further embodiment of a low-pressure die casting device or counter-pressure die casting device

[0084] In the Fig. 2 a further and possibly independent embodiment of the low-pressure die casting device or counter-pressure die casting device is shown, wherein again the same reference numerals or component designations are used for the same parts as in the previous Fig. 1 To avoid unnecessary repetition, please refer to the detailed description in the previous Fig. 1 pointed out or referred to.

[0085] As from Fig. 2As can be seen, it can be provided that the magnetic element 16 is integrated into the mold clamping plate 6 and surrounds the flow connection element 11 in this area.

[0086] In the Figures 3 and 4 a further and possibly independent embodiment of the casting device 1 is shown, wherein again the same reference numerals or component designations are used for the same parts as in the previous Figures 1 and 2 To avoid unnecessary repetition, please refer to the detailed description in the previous Figures 1 and 2 pointed out or referred to.

[0087] Fig. 3 the further embodiment of the casting device 1, in particular in the area of ​​the magnetic element 16, in a schematic cross-sectional view cut through the flow connection element 11 at the level of the electrodes 20, 21.

[0088] In Fig. 4is the further embodiment of the casting device 1, in particular in the area of ​​the magnetic element 16, in a sectional view according to the section line IV - IV according to Fig. 3 shown.

[0089] The further description of this embodiment of the casting device 1 is based on a summary of the Figures 3 and 4 .

[0090] As can be seen from the Figures 3 and 4 As can be seen, it can be provided that the first electrode 20 has a first melt contact surface 24 and the second electrode 21 has a second melt contact surface 25. In the installed state of the electrodes 20, 21, the two melt contact surfaces 24, 25, together with the inner surface 19, can delimit the flow channel of the flow connection element 11.

[0091] Furthermore, it can be provided that a first recess 26 is formed in the flow connection element 11, into which the first electrode 20 is inserted. Furthermore, it can be provided that a second recess 27 is formed in the flow connection element 11, into which the second electrode 21 is inserted. The recesses 26, 27 can penetrate the flow connection element 11.

[0092] A first positioning element 28 can be formed on the first electrode 20, which in the present embodiment is designed, for example, as a shoulder which can be brought into contact with a first contact surface 29 of the flow connection element 11.

[0093] A second positioning element 30 can be formed on the second electrode 21, which in the present embodiment is designed, for example, as a shoulder which can be brought into contact with a second contact surface 31 of the flow connection element 11.

[0094] Furthermore, it can be provided that the first electrode 20 is coupled to a first pole 33 of a power source by means of a first clamping contact 32.

[0095] Furthermore, it can be provided that the second electrode 21 is coupled to a second pole 35 of the power source by means of a second clamping contact 34.

[0096] Furthermore, a first pressing element 36 can be formed, by means of which the first electrode 20 is held in its position in the first recess 26.

[0097] Furthermore, a second pressing element 37 can be provided, by means of which the second electrode 21 can be held in its position in the second recess 27.

[0098] Furthermore, one or more heating elements 38 can be arranged on the first electrode 20. Furthermore, one or more heating elements 39 can be arranged on the second electrode 21. The heating elements 38, 39 can each be arranged on the side surfaces of the electrodes 20, 21.

[0099] How particularly good Fig. 3As can be seen, it can be provided that a first coil 18 is arranged on a first side of the flow connection element 11 and that a second coil 40 is formed on a second side of the flow connection element 11. Furthermore, a magnetic yoke can be formed, for example in the form of a C-shaped iron core or a magnetic core 41, which can have a first open end 42 and a second open end 43. The magnetic core 41 can be arranged such that the flow connection element 11 is arranged between the first open end 42 and the second open end 43 of the magnetic core 41. The first coil 18 can surround the iron core 41 in the region of the first open end 42. The second coil 40 can surround the magnetic core 41 in the region of the second open end 43.

[0100] Fig. 5 shows a further embodiment of the casting device 1. As can be seen from Fig. 5As can be seen, it can be provided that a plurality of flow connection elements 11 are formed, which can be arranged evenly distributed around a center. In the present exemplary embodiment, these are, for example, four flow connection elements 11. Individual magnetic core segments 45 can be arranged between the flow connection elements 11. Each of the magnetic core segments 45 faces a first of the flow connection elements 11 at a first longitudinal end 46 and faces a second of the flow connection elements 11 at a second longitudinal end 47. The first longitudinal end 46 of the magnetic core segment 45 is surrounded by a first of the individual coils 44, and the second longitudinal end 47 of the magnetic core segment 45 is surrounded by a second of the individual coils 44.

[0101] In an alternative embodiment, it is also conceivable for only one individual coil 44 to be formed per magnetic core segment 45. In particular, it can be provided that the individual coil 44 is arranged centrally of the magnetic core segment 45.

[0102] Thus, in the present embodiment, four magnetic core segments 45 are arranged between the four flow connection elements 11, with two of the individual coils 44 being formed for each magnetic core segment 45.

[0103] In further embodiments not shown, these can also be, for example, two, three, five, six, seven, eight or even more flow connection elements 11.

[0104] Furthermore, it is conceivable that the individual coils 44 are coupled to a common power source. In an alternative embodiment, it is also conceivable that the individual coils 44 are each coupled to their own power source and can thus be switched independently of one another.

[0105] Furthermore, it is conceivable that the individual electrodes 20, 21 are coupled to a common power source. In an alternative embodiment, it is also conceivable that the individual electrodes 20, 21 are each coupled to their own power source and can thus be switched independently of one another.

[0106] In the Figure 6 a further and possibly independent embodiment of the casting device 1 is shown, wherein again the same reference numerals or component designations are used for the same parts as in the previous Figures 1 to 5To avoid unnecessary repetition, please refer to the detailed description in the previous Figures 1 to 5 pointed out or referred to.

[0107] As from Fig. 6 As can be seen, it can be provided that the first electrode 20 has a first region 48. Furthermore, it can be provided that the second electrode 21 has a first region 49. Furthermore, it can be provided that the first electrode 20 has a second region 50. Furthermore, it can be provided that the second electrode 21 has a second region 51.

[0108] The first region 48, 49 and the second region 50, 51 can each be loosely adjacent to one another. Furthermore, it is also conceivable for the first region 48, 49 and the second region 50, 51 to be coupled to one another by means of a joint.

[0109] As from Fig. 6clearly visible, it can be provided that the heating elements 38, 39 are arranged in the second area 50, 51.

[0110] In the Figure 7 a further and possibly independent embodiment of the casting device 1 is shown, wherein again the same reference numerals or component designations are used for the same parts as in the previous Figures 1 to 6 To avoid unnecessary repetition, please refer to the detailed description in the previous Figures 1 to 6 pointed out or referred to.

[0111] As from Fig. 7 As can be seen, it can be provided that holes are arranged in the second region 50, 51 and that the heating elements 38, 39 are arranged in the holes.

[0112] Fig. 8 shows a diagram of a time course of a filling process for filling a mold cavity of a casting mold with melt.

[0113] In the Fig. 8Different time profiles of various filling curves with different pressure increases in the flow connection element 11, particularly in the riser pipe 12, are shown. The filling time is plotted on the abscissa. The flow velocity of the melt in the riser pipe 12 is plotted on the ordinate.

[0114] A first filling curve 52 shows the temporal course of the flow velocity of the melt in the riser pipe 12 at a pressure increase of 34 mbar / s and when the magnetic field is activated after a certain time.

[0115] A second filling curve 53 shows the time course of the flow velocity of the melt in the riser pipe 12 at a pressure increase of 24 mbar / s and when the magnetic field is activated after a certain time.

[0116] A third filling curve 54 shows the temporal progression of the melt flow velocity in the riser tube 12 at a pressure increase of 15.7 mbar / s and without activation of the magnetic field during the casting process. This third filling curve 54 represents conventional casting processes as known from the prior art.

[0117] All three filling curves 52, 53, and 54 refer to three identical cast workpieces cast in the same casting device. For all three filling curves 52, 53, and 54, the drop in flow velocity at the end of the filling curve 52, 53, and 54 represents the end of the filling period of the casting process.

[0118] As from Fig. 8As can be seen, with an increased pressure increase, as illustrated by the first filling curve 52, a shortened filling time can be achieved. Despite this shortened filling time, with an increased pressure increase and activation of the magnetic field, as illustrated by the first filling curve 52, an improved cast workpiece can be achieved compared to the casting process known from the prior art according to the third filling curve 54, which has fewer air inclusions.

[0119] The embodiments show possible embodiments, whereby it should be noted at this point that the invention is not limited to the specifically illustrated embodiments thereof, but rather various combinations of the individual embodiments with each other are also possible and this possibility of variation lies within the skill of the person skilled in the art in this technical field due to the teaching of technical action by means of the objective invention.

[0120] The scope of protection is determined by the claims. However, the description and drawings must be used to interpret the claims. Individual features or combinations of features from the various embodiments shown and described may represent independent inventive solutions. The problem underlying these independent inventive solutions can be derived from the description.

[0121] All information on value ranges in this description is to be understood as including any and all sub-ranges thereof, e.g. the information 1 to 10 is to be understood as including all sub-ranges starting from the lower limit of 1 and the upper limit of 10, ie all sub-ranges begin with a lower limit of 1 or greater and end with an upper limit of 10 or less, e.g. 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10.

[0122] For the sake of clarity, it should finally be pointed out that, in order to better understand the structure, some elements have been shown out of scale and / or enlarged and / or reduced in size. Reference symbol list 1 Pouring device 31 second contact surface 2 Oven 32 first terminal contact 3 recording room 33 first power source 4 melt 34 second terminal contact 5 crucible 35 second power source 6 mold clamping plate 36 first pressure element 7 mold 37 second pressure element 8 lower mold part 38 first heating element 9 upper mold part 39 second heating element 10 mold cavity 40 second coil 11 Flow connection element 41 Magnetic core 12 riser pipe 42 first open end of the magnetic core 13 Cut 14 supporting structure 43 second open end of the magnetic core 15 Compressed air supply opening 16 Magnetic element 44 Single coil 17 electromagnet 45 Magnetic core segment 18 first coil 46 first longitudinal end of magnetic core segment 19 inner surface 20 first electrode 47 second longitudinal end of magnetic core segment 21 second electrode 22 Lorzenkraft 48 first area first electrode 23 Conveying direction 49 first area second electrode 24 first melt contact surface 50 second area first electrode 25 second melt contact surface 51 second area second electrode 26 first recess 52 first filling curve 27 second recess 53 second filling curve 28 first positioning element 54 third filling curve 29 first investment area 30 second positioning element

Claims

1. A casting device (1) for casting a melt (4), wherein the casting device (1) has a flow connecting element (11) for conducting the melt (4), wherein a first electrode (20) and a second electrode (21) are arranged on the flow connecting element (11), wherein the first electrode (20) has a first melt contact surface (24) and the second electrode (21) has a second melt contact surface (25), wherein in the installed state of the electrodes (20, 21) the melt contact surfaces (24, 25) are configured for contacting the melt (4) guided in the flow connecting element (11), and that a magnetic element (16) is arranged on the flow connecting element (11), which magnetic element (16) is configured to apply a magnetic field to the region of the melt (4) to which current is applied, whereby a Lorenz force (22) can be exerted on the melt (4) guided in the flow connecting element (11), characterized in that at least one first heating element (38) is arranged in the region of the first electrode (20) and at least one second heating element (39) is arranged in the region of the second electrode (21).

2. The casting device (1) according to claim 1, characterized in that the first heating element (38) and the second heating element (39) are each configured in the form of a resistance heating element, in particular with a ceramic heating conductor.

3. The casting device (1) according to claim 1, characterized in that the first electrode (20) has a rectangular cross-section and in that two of the first heating elements (38) are arranged on opposite sides of the cross section of the first electrode (20).

4. The casting device (1) according to one of the preceding claims, characterized in that the electrodes (20, 21) have a graphite material or an electrically conductive ceramic material in a first region (48, 49) of the melt contact surfaces (24, 25).

5. The casting device (1) according to one of the preceding claims, characterized in that the electrodes (20, 21) have an austenitic material in a second region (50, 51) facing away from the melt contact surfaces (24, 25).

6. The casting device (1) according to claim 5, characterized in that bores are formed in the second region (50) of the first electrode (20), in which bores rod-shaped first heating elements (38) are arranged.

7. The casting device (1) according to one of the preceding claims, characterized in that the magnetic element (16) comprises a first coil (18) and a second coil (40), which are arranged on two diametrically opposite sides of the cross section of the flow connecting element (11).

8. The casting device (1) according to claim 7, characterized in that the magnetic element (16) comprises a magnetic core (41) which is C-shaped and is arranged in such a way in the region of the flow connecting element (11) that the flow connecting element (11) is arranged between a first open end (42) of the magnetic core (41) and a second open end (43) of the magnetic core (41), wherein the first coil (18) surrounds the first open end (42) of the magnetic core (41) and the second coil (40) surrounds the second open end (43) of the magnetic core (41).

9. The casting device (1) according to one of claims 1 to 6, characterized in that a plurality of the flow connecting elements (11) are formed, which are arranged uniformly distributed around a center, wherein individual magnetic core segments (45) are arranged between the flow connecting elements (11), wherein a magnetic core segment (45) faces a first one of the flow connecting elements (11) at a first longitudinal end (46) and faces a second one of the flow connecting elements (11) at a second longitudinal end (47), wherein the first longitudinal end (46) of the magnetic core segment (45) is surrounded by a first one of the individual coils (44) and the second longitudinal end (47) of the magnetic core segment (45) is surrounded by a second one of the individual coils (44).

10. The casting device (1) according to one of claims 7 to 9, characterized in that a cooling device is formed in the region of the coils (18, 40, 44).

11. The casting device (1) according to one of the preceding claims, characterized in that the electrodes (20, 21) are each coupled to current sources by means of releasable clamping contacts (32).

12. A method for casting a melt (4), wherein the melt (4) of the metallic material is conveyed through a flow connecting element (11) during the casting process, wherein current is applied in the region of the flow connecting element (11) by means of a first electrode (20) and a second electrode (21), which contact the metallic material by means of melt contact surfaces (24, 25), and simultaneously a magnetic field acts on the region of the melt (4) to which current is applied, whereby a Lorenz force (22) is exerted on the melt (4) guided in the flow connecting element (11), characterized in that the electrodes (20, 21) are heated as required by means of heating elements (38, 39), wherein at least one first heating element (38) is arranged in the region of the first electrode (20) and at least one second heating element (39) being arranged in the region of the second electrode (21).

13. The method according to claim 12, characterized in that a casting device (1) is used for casting the melt (4), which casting device (1) is configured as a low-pressure casting device or as a counter-pressure casting device, wherein the casting device (1) comprises a furnace (2) in which a receiving space (3) is formed to receive melt (4), wherein the receiving space (3) is coupled to a casting mold (7) by means of the flow connecting element (11), wherein - at the start of the casting process, the pressure in the receiving space (3) is increased in order to force the melt (4) through the flow connecting element (11) into the casting mold (7), wherein - only when a predefined amount of melt which has flown through the flow connecting element (11) is reached is current applied to the melt in the flow connecting element (11) and at the same time the magnetic field which acts on the region of the melt (4) to which current is applied is activated in order to brake the melt in the flow connecting element (11).

14. The method according to claim 13, characterized in that the pressure in the receiving space (3) is increased in such a way that a constant pressure increase, in particular a pressure increase between 16 mbar / s and 45 mbar / s, preferably between 23 mbar / s and 35 mbar / s, takes place at an inlet of the casting mold (7).

15. The method according to claim 13 or 14, characterized in that current is applied to the melt in the flow connecting element (11) and the magnetic field, which acts on the region of the melt (4) to which current is applied, is activated in order to brake the melt in the flow connecting element (11) when a melt level of the melt (4) flows from a gate (13) into a mold cavity (10).

16. The method according to one of claims 13 to 15, characterized in that a simulation model is used to calculate at which pressure increase and at which activation times and activation intensities of the magnetic field and at which activation times and activation intensities of the current application to the melt (4) a casting process with as few blowholes as possible in the cast workpiece can be achieved.

17. The method according to one of claims 12 to 16, characterized in that the electrodes (20, 21) are heated when the melt flow in the flow connecting element (11) is stopped, in particular that a heating process for heating the electrodes (20, 21) is started with a lead time before the melt flow is stopped or before the flow rate falls below a minimum flow rate, wherein the lead time is between 1 second and 180 seconds, in particular between 5 seconds and 120 seconds, preferably between 10 seconds and 60 seconds.

18. The method according to one of claims 12 to 17, characterized in that current is applied to the melt in the flow connecting element (11) and the magnetic field, which acts on the region of the melt (4) to which current is applied, is activated in order to brake the melt in the flow connecting element (11) even before a melt level of the melt (4) flows from a gate (13) into a mold cavity (10), and that the pressure in the receiving space (3) is increased in the meantime and that the magnetic field is deactivated at a predetermined point in time.