Method and system for casting a metal

Abstract

A system (1) for casting a metal (2), the system (1) comprises a mould (6) comprising a feeder (4) for feeding a cast part (3). The system comprises an isolating sleeve (10) enclosing at least a part of the feeder (4) and an induction coil element (20) for arrangement on the outside of the isolating sleeve (10). The induction coil element (20) comprises an induction coil (21) and a cooling channel (22) for controlling the temperature of the metal (2) in the feeder (4). The system (1) comprises a control unit (30) connected to the induction coil element (20) for controlling power to the induction coil (21) and providing a flow of coolant to the cooling channel (22). The system further comprises a temperature sensor (40) for sensing a temperature at a fixed position in the feeder (4), the temperature sensor (40) being in communication with the control unit (30).

Description

[0001] METHOD AND SYSTEM FOR CASTING A METAL

[0002] TECHNICAL FIELD

[0003] The invention relates to metal casting, and more specifically to improved utilization of the feeder in metal casting.

[0004] BACKGROUND

[0005] In metal casting, feeders are utilized to fill in the metal volume of the cast part that has been reduced in the mould due to thermal contraction. As the temperature of the metal decreases, the metal density increases. A feeder is a volume of the mould which is occupied by molten metal when the metal is in a liquid phase, and acts as a reservoir to feed metal to the cast part as the metal solidifies. The main principle behind feeder design has traditionally been to design a mould with a feeder volume large enough to ensure that the metal in the lower part of the feeder, closest to the cast part, solidifies after the cast part. It is further desirable to prevent negative solidification effects such as cavitation into the cast part, material tension, poor material quality and cracks. To achieve this, and in addition have some margin, the feeder has traditionally been designed quite large, so large that the expense of additional heating, additional material cost, and cost of excess material handling has been significant.

[0006] To delay the solidification in the feeder, i.e. to prolong the liquid phase of the metal in the feeder, an exothermic sleeve is known to be provided around the feeder. This exothermic sleeve may control the temperature of the metal in the feeder, and such an element may be placed onto an isolating sleeve encompassing the feeder and either directly or indirectly control the temperature of the metal in the feeder. An isolating sleeve is known to be provided around the feeder, to restrict the molten metal and to define the feeder volume. Due to restrictions in shape and material, known isolating sleeves are prone to significant heat transfer from the molten metal to the surrounding mould.

[0007] Further, no technical solution has been able to feed a metal casting aiming for 100% yield of the metal in the feeder. Traditionally, the volume of metal in the feeder is large, and a casting process therefore causes wear and tear of the machines and equipment, causes excess energy usage and may be limited by available furnaces and crucibles. It is a problem in the art of metal casting to precisely control the feeding of molten metal into the cast part from the feeder, due to solidification inside the feeder itself. This leads to excess use of molten metal and energy for melting the solidified metal. Current technologies for feeding metal castings is related directly to both total volume of casting, determining the amount of metal needed from the feeder, and the largest sphere of the cast part. This determines the solidification time and thus the time period that feeding is needed. There is a need for a system which accurately adjusts the temperature of the metal in the feeder, to precisely control the solidification of the metal in the feeder and thus maximize the utilization of the feeder.

[0008] Common methods of metal casting comprise several steps that are tedious to prepare, and also comprise elements that can only be utilized only once. Preparing a mould and feeder design, installing an isolating sleeve, etc. makes traditional metal casting a tedious process poorly adapted for series production of a cast part.

[0009] There is therefore a need for an improved method and system of metal casting to reduce or eliminate the above-mentioned disadvantages of known techniques. Documents useful for understanding the field of technology include JP4494868B2, JPH09314310A and US8056608B2.

[0010] SUMMARY OF THE INVENTION

[0011] It is an object of the invention to mitigate, alleviate or eliminate one or more of the above-identified deficiencies and disadvantages in the prior art and solve at least the above-mentioned problem. It is further an object of the invention to provide a method and a structure that can minimize, or at least reduce, the size of the feeder and the amount of molten metal in the feeder. It is an object of the invention to reduce heating cost of the feeder. It is an object of the invention to minimize the resulting excess material volume of the cast part and minimize the material inventory of the casting process. It is an object of the invention to provide a method and a structure that can improve the quality of the resulting cast part in terms of production price, reduction or elimination of structural deficiencies such as cavities, cracks, phase homogeneity and surface tension.

[0012] According to a first aspect, there is provided a system for casting a metal, the system comprising: a mould comprising a feeder for feeding a cast part; an isolating sleeve enclosing at least a part of the feeder; an induction coil element for arrangement on the outside of the isolating sleeve, the induction coil element comprising an induction coil and a cooling channel for controlling the temperature of the metal in the feeder; a control unit connected to the induction coil element for controlling power to the induction coil and providing a flow of coolant to the cooling channel; a temperature sensor for sensing a temperature at a fixed position in the feeder, the temperature sensor being in communication with the control unit.

[0013] According to an embodiment, the temperature sensor is connected to the induction coil element by a sensor support element.

[0014] According to an embodiment, the sensor support element comprises a base for fixation to the top of induction coil elements of different diameters and a retaining element for fixing the temperature sensor in a vertical direction.

[0015] According to an embodiment the isolating sleeve comprises a disc element removably connected to a tube element.

[0016] According to an embodiment the tube element comprises a stopping element and the disc element comprises an opening, the disc element has an outer diameter which extends further out in a radial direction than the stopping element, wherein the disc element is configured to be threaded onto the tube element and abut the stopping element.

[0017] According to an embodiment the disc element is formed by an insulating material and the tube element is formed by a heat shock resistant material.

[0018] According to an embodiment the induction coil element is a tubular element, and the induction coil and the cooling channel are embedded in the induction coil element.

[0019] According to a second aspect, there is provided a method of casting a metal, the method comprising the steps of: providing a mould comprising a feeder and an isolating sleeve, the isolating sleeve enclosing at least a part of the feeder; arranging an induction coil element on the isolating sleeve; connecting the induction coil element to a control unit for controlling the temperature of metal in the feeder; filling the mould with molten metal; measuring or predicting the temperature at a fixed position in the feeder; controlling solidification of the metal in the feeder by controlling the temperature generated by the induction coil element; removing the induction coil element from the isolating sleeve and the mould. According to an embodiment, the step of providing a mould comprising a feeder and an isolating sleeve in addition comprises providing a dummy coil element, the dummy coil element enclosing at least part of the isolating sleeve, and the method further comprises a step of extracting the dummy coil element from the isolating sleeve before the step of arranging the induction coil element on the isolating sleeve.

[0020] According to an embodiment, the induction coil element comprises an induction coil and a cooling channel, and controlling the temperature generated by the induction coil element comprises adjusting the power of the induction coil based on the measured or predicted temperature at a fixed position in the feeder.

[0021] BRIEF DESCRIPTION OF THE FIGURES

[0022] The aspects of the invention, including its particular features and advantages, will be readily understood from the following detailed description and the accompanying figures. The figures are provided to illustrate the general structures of the invention. Like reference numerals refer to like elements throughout.

[0023] Fig. 1 shows an isometric view of elements of a system for casting a metal, comprising a cast part, an isolating sleeve, an induction coil element and a control unit.

[0024] Fig. 2 shows a section view through elements of a mould for casting a metal. Metal in a liquid phase is shown in the cast part and the feeder.

[0025] Fig. 3 shows an isometric exploded view of an isolating sleeve, induction coil element and temperature sensor.

[0026] Fig. 4a-4g show in section views steps of a method for casting a metal.

[0027] DETAILED DESCRIPTION

[0028] The invention will now be described with reference to the accompanying figures, in which preferred example embodiments of the invention are shown. The invention may, however, be embodied in other forms and should not be construed as limited to the herein disclosed embodiments. The disclosed embodiments are provided to fully convey the scope of the invention to the skilled person.

[0029] It is also to be understood that the terminology used herein is for purpose of describing particular embodiments only, and is not intended to be limiting. It should be noted that, as used in the specification and the appended claim, the articles "a", "an" and "the" are intended to mean that there are one or more of the elements or steps unless the context explicitly dictates otherwise. Thus, for example, reference to "a unit" or "the unit" may include several devices, and the like. Furthermore, the words "comprising", "including", "containing" and similar wordings does not exclude other elements or steps.

[0030] With reference to figures 1 , 2 and 3, a system 1 for casting a metal 2 is illustrated. When a cast part 3 is cast, metal 2 is present in the volume of the cast part 3, in a feeder 4, and in a runner or ingate 5 (not shown in figures 1 -3, see figures 4a-4g). The cast part 3 is illustrated as a sphere. The mould 6 is not shown in figures 1 -3, this is shown in figures 4a-4g. The feeder 4 is thus part of the cast part 3, utilized to fill in the metal volume of the cast part 3 that has been reduced due to thermal contraction. The volume of the feeder 4 is thus dependent on the volume of metal 2 to be fed to the cast part 3, followed by solidification. Metal 2 is fed to the cast part 3 and feeder 4 through the ingate 5, this is described more in detail with reference to figures 4a-4g.

[0031] An isolating sleeve 10 defines the feeder 4 in the mould. The isolating sleeve 10 is positioned on top of the cast part 3. At least a part of the isolating sleeve 10 is heat shock resistant. The isolating sleeve 10 acts as an isolating layer between the molten metal 2 inside the feeder 4 and the surrounding mould, both in a radial direction of the feeder 4, but also to separate the volume outside the feeder 4 from the cast part 3 below. The isolating sleeve 10 comprises two separate elements, a disc element 10a and a tube element 10b. The disc element 10a may be a generally flat element, e.g. manufactured from a plate. The disc element 10a comprises an opening 1 1. The opening 1 1 preferably extends through the disc element 10a in a direction perpendicular to the disc element 10a. The opening 11 may be positioned centrally on the disc element 10a, such that the disc element 10a has the shape of a revolved cross section.

[0032] The tube element 10b may have an outer diameter corresponding to or being a little less than the diameter of the opening 11 of the disc element 10a. The disc element 10a is thus configured for being threaded onto the tube element 10b. The tube element 10b further comprises a stopping element 12. The stopping element 12 is preferably provided at a longitudinal end of the tube element 10b. The disc element 10a has an outer diameter which extends further out in a radial direction than the stopping element 12. The stopping element 12 may preferably be a circumferential flange extending around the periphery of the tube element 10b. The stopping element 12 is configured to abut the disc element 10a, and the disc element 10a may thus rest on the stopping element 12, as illustrated in figure 2.

[0033] Because the isolating sleeve 10 is made from two separate elements, manufacturing and transport of the isolating sleeve 10 is greatly simplified. The disc element 10a may e.g. be manufactured by die cutting a plate, casting in a mould, or by other known methods of manufacturing a disc element. Manufacturing the tube element 10b may also be greatly simplified. Transport of isolating sleeves 10 may also be more efficient in that disc elements 10a and tube elements 10b may be transported separately, and thus allows a plurality of the two separate elements to be transported in a much more compact and space-efficient way.

[0034] The disc element 10a may be made from a different material than the tube element 10b, allowing optimal material properties for each of the two elements of the isolating sleeve 10. The disc element 10a is not in direct contact with the molten metal 2 and can have different material properties than the tube element 10b. In one embodiment, the tube element 10b is made of a heat shock resistant material, preferably a fibrous heat shock resistant material, and the disc element 10a is made of a material with increased isolating properties, but which may not be heat shock resistant. The isolating sleeve 10 is preferably not made from a metal, as it would interfere induction heating of the metal 2 in the feeder 4.

[0035] The system 1 comprises an induction coil element 20. The induction coil element 20 is preferably a tube-shaped element comprising an induction coil 21 and a cooling channel 22. The cooling channel 22 may be embedded into the induction coil 21 , as in the illustrated embodiment. The induction coil element 20 is configured for arranging on the outside of the isolating sleeve 10, and may be threaded onto the isolating sleeve 10 and rest on the disc element 10a. The isolating sleeve 10 separates and acts as an isolating layer between the molten metal 2 in the feeder 4 and the induction coil element 20. The induction coil element 20 may therefore be installed or removed independently of the presence of metal 2 in the feeder 4. As the induction coil element 20 is powered, the induction coil 21 acts together with the metal 2 in the feeder 4 to heat or maintain the temperature of the metal 2 by induction heating.

[0036] The induction coil 21 and cooling channel 22 are preferably embedded into the induction coil element 20, and are therefore protected by the outside of the coil element 20. The induction coil element 20 is therefore one element that may be relocated from one mould to another, and comprises means for controlled heating and cooling of the feeder 4. As the induction coil element 20 is threaded onto the isolating sleeve 10, the induction coil 21 and cooling channel 22 are thus arranged around the feeder 4. The induction coil element 20 may comprise hoisting means 23, to provide easy and secure lifting and hoisting of the induction coil element 20. The hoisting means 23 may be pad eyes, or similar means known in the art of hoisting. The induction coil element 20 may be lifted by crane, forklift or other means known in the art of lifting. The induction coil element 20 is thus easily lifted from e.g. one system 1 for casting a metal to another.

[0037] In an embodiment, the induction coil 21 comprises two induction coils; a first induction coil 21 a and a second induction coil 21b. The induction coil element 20 may thus comprise at least one induction coil, and may preferably comprise at least two induction coils. The first and second induction coils 21 a, 21b are preferably arranged successively along the length of the induction coil element 20. The at least two induction coils 21 a, 21 b may be independently controlled, such that power is distributed to both induction coils 21 a, 21b when the feeder 4 is full of metal 2, but as the level of metal 2 in the feeder 4 decreases, power is only distributed to the lower second induction coil 21b. This renders the system 1 energy-efficient.

[0038] The induction coil element 20 is connected to a control unit 30 by connection means 31 , as illustrated in figure 1 . The connection means 31 may comprise cables and tubes for conveying electric power and providing and receiving coolant from the induction coil element 20. The coolant may preferably be cooling liquid. The control unit 30 may in addition be in wireless communication with the induction coil element 20. The control unit 30 is preferably a separate unit, configured to power the induction coil 21 . The power input to the induction coil element 20 (and thus the frequency of the induction coil 21 ) is dependent on the volume, alloy and temperature of the metal 2 in the feeder 4. The power input may also account for heat loss through the isolating sleeve 10. The control unit 30 may also control a flow of coolant to the cooling channel 22. The flowrate of coolant may be fixed. The control unit 30 may also cool the coolant as it is received from the induction coil element 20. The control unit 30 is thus able to control the temperature of the metal 2 in the feeder 4.

[0039] The system 1 comprises a temperature sensor 40, for sensing the temperature of the metal 2 at a fixed position in the feeder 4. The temperature sensor 40 may comprise an elongate element. An elongate element allows the temperature sensor to be connected to e.g. the induction coil element 20 away from where the actual temperature is measured, and be supported in a fixed position. The temperature sensor 40 may in one embodiment be a thermocouple, as in the illustrated embodiment. The temperature sensor 40 is preferably fixed to the induction coil element 20. More preferably, the temperature sensor 40 is fixed to an upper portion of the induction coil element 20. The induction coil element 20 may comprise end-surfaces at each lateral end thereof. The temperature sensor 40 may thus be connected to a top surface 24 of the induction coil element 20. More preferably, the temperature sensor 40 may be connected to the induction coil element 20 by a sensor support element 41 . The sensor support element 41 may be releasably connected to the top surface 24. Preferably, the sensor support element

[0040] 41 comprises a base 42 for fixation to the induction coil element 20. The base 42 is configured for connection to induction coil elements 20 of different diameters. The base 42 may comprise a curved portion, as in the illustrated embodiment. The base

[0041] 42 may further comprise elongated slots 43 through which fastening means may be provided, for easy adaptation to e.g. top surfaces 24 of induction coil elements 20 of different diameters.

[0042] The sensor support element 41 may further comprise a retaining element 44. A first element of the retaining element 44 may be fixed to the base 42. A second element may be adjustable and lockable such as to bias and retain the temperature sensor 40 in the retaining element 44. The second element can be tightened to securely hold the temperature sensor 40 in a fixed position. As the temperature is measured at a fixed position inside the molten metal 2, detailed information of the temperature, feeder volume, etc. can be monitored and used to accurately control the temperature and the solidification of the metal 2 in the feeder 4. The data may also be used in following castings.

[0043] The temperature sensor 40 may be arranged in the feeder 4 such that the temperature is measured generally in the centre of the feeder 4 in a radial direction (and consequently in the centre of the isolating sleeve 10 and induction coil element 20). The temperature sensor 40 may further be arranged such that the temperature is measured in a lower portion of the feeder, e.g. next to the cast part 3. As the metal 2 in the cast part 3 and feeder 4 eventually solidifies, the temperature sensor 40 can be adjusted and arranged before the molten metal 2 is poured into the mould, such that the temperature sensor 40 is not embedded in the solidified metal. The temperature sensor 40 may thus be re-used in a later casting process. As the utilization of the metal 2 in the feeder 4 is very high, the temperature sensor 40 may be provided fixed in the feeder 4 adjacent the cast part 3.

[0044] The sensed temperature from the temperature sensor 40 is communicated to the control unit 30. The communication may be wirelessly or by the connection means 31 . In response to the sensed temperature, the control unit 30 may increase or decrease power to the induction coil element 20, so as to increase or decrease the temperature of the metal 2 in the feeder 4. Further, as the solidification temperature of the metal 2 in the system 1 is known, the control unit 30 determines the amount of power to be conveyed to the induction coil 21 in order to generate an optimal solidification sequence. The amount of coolant to be conveyed to the cooling channel 22 may alternatively also be controlled. The amount of heating the induction coil element 20 provides to the feeder 4 is based on the sensed temperature in the feeder 4. As the exact temperature in the feeder 4 is known and controlled, the need for considering the largest sphere of the cast part is eliminated. This yields a great advantage for the system 1 .

[0045] Referring now to figures 4a-4g, a method of casting a metal 2 is described. The control unit 30 is not shown in figures 4a-4g. Initially, as shown in figure 4a, a system 1 comprising a mould 6 is provided. The mould 6 may in one embodiment comprise a sand mould, but may in other embodiments comprise other moulds, such as a high pressure die casting. The mould 6 comprises a feeder 4 and an ingate 5. The feeder 4 is defined by an isolating sleeve 10 forming part of the mould 6. The system 1 may further comprise a dummy coil element 50. The mould 6 may be made with the dummy coil element 50 positioned onto the isolating sleeve 10, and a step of providing a mould 6 may comprise providing a dummy coil element 50. The dummy coil element 50 may prevent sand from the mould 6 from entering the space where the induction coil element 20 is to be arranged in a later step, and may also enable easy removal of the induction coil element 20 by occupying more space than the induction coil element 20. The step of providing the isolating sleeve 10 and dummy coil element 50 allows preparation of the mould 6 prior to filling the mould 6 with molten metal 2. As such, the induction coil element 20 may be provided only when it is needed, i.e. during filling of the mould 6 and solidification of the metal 2 in the feeder 4.

[0046] The isolating sleeve 10 is preferably made from two separate elements, as described previously with reference to figure 3. The isolating sleeve 10 encloses at least part of the feeder 4. When the mould 6 with the dummy coil element 50 has been provided, the dummy coil element 50 is removed, as indicated in figure 4b. A space 51 in the form of an annulus is left empty in the mould 6 around the isolating sleeve 10. In a next step, the induction coil element 20 is installed in the space 51 , this allows for effective utilization of the induction coil element 20, and thus effective series production.

[0047] A next step is installing an induction coil element 20 into the mould 6, this is shown in figure 4c. The induction coil element 20 is threaded onto the isolating sleeve 10 and into the space 51 . The induction coil element 20 comprises an induction coil and cooling channel (not shown in figures 4a-4g) as described with reference to figure 2. The method further comprises connecting the induction coil element 20 to a control unit 30 (not shown in figures 4a-4g) as described with reference to figure 1 . The induction coil element 20 may alternatively be connected to the control unit 30 prior to being installed in the mould 6.

[0048] When the induction coil element 20 is installed in the mould 6, it occupies most of the space 51 , as shown in figure 4d. The temperature sensor 40 may be provided on the induction coil element 20 after the induction coil element 20 is installed onto the isolating sleeve 10, and the temperature sensor 40 may be connected to the induction coil element 20 as described with reference to figures 2 and 3. The temperature sensor 40 may thus measure the temperature at a fixed location in the feeder 4. Alternatively, the temperature sensor 40 may be provided on the induction coil element 20 prior to installing the induction coil element 20 onto the isolating sleeve 10. E.g. if the level of the metal in the feeder 4 after solidification is known before the process of casting is initiated, the lowest portion of the temperature sensor 40 is advantageously placed such that the temperature sensor 40 is positioned just above the solidified metal 2 in the feeder 4. When the induction coil element 20 is connected to the control unit 30, the mould 6 is ready to receive molten metal.

[0049] The next step is filling the mould 6 with molten metal 2. Figure 4e shows molten metal 2 in the mould 6. The molten metal 2 is fed to the cast part 3 through the ingate 5. Molten metal 2 rises through the cast part 3 and is also present in the feeder 4 as the mould 6 is filled. The metal 2 is indicated in figure 4e with a honeycomb pattern. Solidification of the metal 2 takes place from figure 4e to figure 4f. As the density of solidified metal is higher than the density of molten metal, the volume of the metal 2 decreases as the metal 2 solidifies. The solidification of the metal 2 in the feeder 4 is controlled by monitoring the temperature of the metal 2 in the feeder 4, and maintaining a liquid phase as the cast part 3 solidifies. By keeping the temperature of the metal 2 in the feeder 4 higher than the temperature of the cast part 3, solidification of the metal 2 in the feeder 4 is prevented. This is achieved by the control unit controlling the temperature generated by the induction coil element 20. The temperature of the metal 2 in the feeder 4 may be precisely monitored due to the temperature sensor 40. The precise temperature of the metal 2 in the feeder 4 is thus monitored, and the temperature of the metal 2 in the feeder 4 may e.g. be kept just above the solidification temperature, to minimize energy usage and accommodate a controlled and optimized solidification. If the temperature sensor 40 is positioned just above the cast part 3 (i.e. in the lower part of the feeder 4) the temperature at the upper part of the cast part 3 is known, and the temperature of the metal 2 in the feeder 4 can be further precisely monitored.

[0050] Figure 4g shows the removal of the induction coil element 20 from the isolating sleeve 10 and the mould 6. This step may be when the cast part 3 is solidified, or when the feeder 4 is no longer needed. The induction coil element 20 may be removed immediately when it is no longer needed, and as such, the utilization of the induction coil element 20 is maximized. The temperature sensor 40 may be removed together with the induction coil element 20, and the induction coil element 20 and temperature sensor 40 may be re-used in a next metal casting process. If the next metal casting is identical to the previous, the induction coil element 20 can remain connected to the control unit, and the next metal casting can be rapidly initiated. If a similar metal casting is to be executed, the data from the sensed temperature of the temperature sensor 40 can be utilized to predict the solidification of the subsequent casting process, and a temperature sensor 40 may even be omitted. Temperature data such as a temperature curve for the system 1 and mould 6, at the measured fixed position in the centre of the feeder 4, can be stored and used for training a program to e.g. predict other temperature curves and predict solidification of metal 2 in systems 1 that has not been directly measured.

[0051] As is known in the art of producing a cast metal part, the cast part 3 may need to be further processed. But as the amount of metal 2 in the feeder 4 is minimized, the cast part 3 needs less such processing, and there is less waste material from the casting process.

[0052] While the invention has been described with reference to the embodiments mentioned above, it is to be understood that modifications and variations can be made without departing from the scope of the present invention, and such modifications and variations shall remain within the field and scope of the invention, as defined by the appended claims.

Claims

CLAIMS1 . A system (1) for casting a metal (2), the system (1) comprising: a mould (6) comprising a feeder (4) for feeding a cast part (3); an isolating sleeve (10) enclosing at least a part of the feeder (4); an induction coil element (20) for arrangement on the outside of the isolating sleeve (10), the induction coil element (20) comprising an induction coil (21 ) and a cooling channel (22) for controlling the temperature of the metal (2) in the feeder (4); a control unit (30) connected to the induction coil element (20) for controlling power to the induction coil (21) and providing a flow of coolant to the cooling channel (22); a temperature sensor (40) for sensing a temperature at a fixed position in the feeder (4), the temperature sensor (40) being in communication with the control unit (30).

2. The system (1) for casting a metal (2) according to claim 1 , wherein the temperature sensor (40) is connected to the induction coil element (20) by a sensor support element (41 ).

3. The system (1) for casting a metal (2) according to claim 2, wherein the sensor support element (41 ) comprises a base (43) for fixation to the top of induction coil elements (20) of different diameters and a retaining element (44) for fixing the temperature sensor (40) in a vertical direction.

4. The system (1) for casting a metal (2) according to any one of claims 1 -3, wherein the isolating sleeve (10) comprises a disc element (10a) removably connected to a tube element (10b).

5. The system (1) for casting a metal (2) according to claim 4, wherein the tube element (10b) comprises a stopping element (12) and the disc element (10a) comprises an opening (11 ), the disc element (10a) has an outer diameter which extends further out in a radial direction than the stopping element (12), wherein the disc element (10a) is configured to be threaded onto the tube element (10b) and abut the stopping element (12).

6. The system (1) for casting a metal (2) according to claim 4 or 5, wherein the disc element (10a) is formed by an insulating material and the tube element (10b) is formed by a heat shock resistant material.

7. The system (1) for casting a metal (2) according to any one of claims 1 -6, wherein the induction coil element (20) is a tubular element, and the induction coil (21) and the cooling channel (22) are embedded in the induction coil element (20).

8. A method of casting a metal (2), the method comprising the steps of: providing a mould (6) comprising a feeder (4) and an isolating sleeve (10), the isolating sleeve (10) enclosing at least a part of the feeder (4); arranging an induction coil element (20) on the isolating sleeve (10); connecting the induction coil element (20) to a control unit (30) for controlling the temperature of metal (2) in the feeder (4); filling the mould (6) with molten metal (2); measuring or predicting the temperature at a fixed position in the feeder (4); controlling solidification of the metal (2) in the feeder (4) by controlling the temperature generated by the induction coil element (20); removing the induction coil element (20) from the isolating sleeve (10) and the mould (6).

9. The method of casting a metal (2) according to claim 8, wherein the step of providing a mould (6) comprising a feeder (4) and an isolating sleeve (10) in addition comprises providing a dummy coil element (50), the dummy coil element (50) enclosing at least part of the isolating sleeve (10), and the method further comprises a step of extracting the dummy coil element (50) from the isolating sleeve (10) before the step of arranging the induction coil element (20) on the isolating sleeve (10).

10. The method of casting a metal (2) according to claims 8 or 9, wherein the induction coil element (20) comprises an induction coil (21 ) and a cooling channel (22), and controlling the temperature generated by the induction coil element (20) comprises adjusting the power of the induction coil (21) based on the measured or predicted temperature at a fixed position in the feeder (4).

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