MXPA06005979A - Casting of metal artefacts - Google Patents

Abstract

The invention provides a process, casting assembly (10) and casting apparatus for charging a mould (12) with molten metal and solidifying it in the mould to form an artefact, the process including, prior to charging the mould, heating the mould by induction heating to an elevated temperature at which the charging takes place. The assembly (10) includes a mould (12) for casting he artefact and an induction heating arrangement (14), which includes at least one induction coil surrounding the mould, for heating it to an elevated temperature prior to the casting. The apparatus (20) includes the assembly (10) and a melting apparatus (4) for forming a molten charge of metal, the apparatus (40) including a heating arrangement (44) for heating a precursor of the molten charge to melt it.

Description

MOLDING METAL ARTIFACTS Description of the Invention The present invention is concerned with the molding of a metal artifact. More particularly, the invention is concerned with a process for molding a metal device, with a molding assembly for molding metal artifacts and with a molding apparatus or installation for molding a metal device, all being particularly suitable for molding artifacts. of light metal. As used herein, the term "light metal" encompasses both light metals such as and alloys thereof in which one or more light metals form the greater proportion of more than 50% by mass, light metals are those that have a density of less than 2.7 g / cm3. Usually light metals have low melting points of 660 ° C or lower. According to a first aspect of the invention, there is provided a process for molding a metal artefact by loading a die or mold with molten metal and causing or allowing the metal to solidify in the die or mold to form the artifact, the process includes the stage, before the loading of the die or mold with the molten metal, of heating the matrix or mold by induction heating to an elevated temperature, the charging takes place with the die or mold at the elevated temperature, heating by induction is used to provide the surface of the interior of the matrix or mold with a desired temperature profile, by which the inner surface of the matrix or mold has different parts or zones at different temperatures from each other, in contact with the metal melt charged to the die or mold, to promote by this desired cooling and solidification rates in different parts of the material charged to the die or molds and the The charge of the matrix or mold is of a fusion apparatus that has the capacity to produce a full load of polished metal that is matched or correspond in volume with the capacity or volume of the matrix or mold, the charge of the matrix or mold is With enough molten metal to produce a single appliance and the load acts completely to consume a full molten charge produced by the melting apparatus, the heating arrangement of the melting apparatus is an induction heating arrangement comprising at least one coil of induction. The process may include the step of purging the matrix or mold, prior to heating, such that the molding of the artifact takes place under a desired atmosphere. Instead of or in addition, the purge can be carried out during heating of the die or mold. Thus, in other words, the process may include the step, before loading the die or mold, of purging the die or mold with a purge gas, charging takes place under an atmosphere provided by the purge gas. Preferably, the purge is carried out both before and during the heating of the die or mold, the purge is discontinued before the charging takes place. The purge gas can be selected from the group consisting of argon, carbon dioxide and mixtures thereof. Instead of this, the purge can be by means of a gas such as sulfur hexafluoride (SFe) which can act as an alkaline flux. The process may include the step, before loading the matrix or mold with molten metal, of sealing or blocking the die or mold. In addition to the same, the process may include the step of disconnecting the supply of purge gas to the die or mold, prior to loading the die or mold with the molten metal. Commonly, the supply of purge gas is discontinued when the matrix or mold reaches its operating temperature. The charge of the matrix or mold will be carried out commonly to fill the matrix or mold to its full capacity. The load can be carried out under reduced pressure, which acts to fill the matrix or mold to its full capacity. In particular and preferably, the filling of the matrix or mold with the load is under an intermediate pressure, not being what is known in the art as low pressure injection molding or what is known in the art as high pressure injection molding. More particularly, charging can be effected by injection molding at an intermediate pressure in the range of 50 KPa-30 MPa. It will be appreciated that routine experimentation can be used to determine a desired or optimum intermediate pressure under which the die or mold must be filled with the molten charge. The process can include using the metal as a selected metal consisting of aluminum, magnesium, lithium, zinc and alloys thereof. Preferably, the process includes using the metal as a light metal consisting of magnesium, aluminum. and alloys thereof. The process is expected to be useful in particular in the molding of light metal or alloy products selected from the group consisting of tire wheels such as aluminum or magnesium alloy wheel wheels, automotive gearboxes, steering wheels, housing of steering columns, auxiliary brake parts or components and automotive, marine and aircraft engine parts or components. Commonly, the process will be used in the molding of aluminum wheels and magnesium alloy. Thus, the molding can be of a light metal artifact in the form of a motorized vehicle wheel wheel. In particular, the process is expected to be useful in molding artifacts having cross-sectional thicknesses in the range of 1.5-30 mm, usually 2-25 mm, with respective masses of 0.25-30 kg, usually 0.5-20 kg. In other words and more particularly, the molding can be of a metal artifact in which part of the solidified artifact that is farthest from the surface of the artifact is spaced from the nearest part of the artifact surface by a spacing of 0.75 - 15mm, the artifact has a mass of 0.25 - 30 Kg. Importantly, the process may include the step of providing the matrix or mold with a desired temperature profile, by the selective application of induction heating to it, to promote the solidification at desired speeds of different parts of the molten light metal charged to the die or mold. In addition, the charge of the die or mold can be from a melting apparatus that is movable alternatively in relation to the die or mold, the process includes moving the melting apparatus alternately between a loading position, where it is loaded with a precursor of the molten charge and a filling position wherein the molten charge is transferred from the melting apparatus to the molding assembly. The molding can be carried out in a variety of matrices or molds each associated with a single melting apparatus which is loaded,. Each melting apparatus is associated with a single die or mold and is electrically heated by induction heating, a common power source is used to supply electric power to the dies or molds for induction heating thereof and a source of heat. Common electrical power is used to supply electrical power to the fusion devices. The process may be carried out by using a molding apparatus or installation as defined hereinbelow. According to another aspect of the invention, there is provided a molding apparatus or installation for molding metal artifacts, the apparatus or installation includes a molding assembly for molding an artifact and metal, the molding assembly includes a mold or mold for molding the artifact and also includes an induction heating arrangement, the induction heating arrangement includes at least one induction coil surrounding the die or mold, to heat the die or mold to a high temperature prior to molding the artifact, the The induction heating arrangement includes a plurality of at least two such induction coils that are operable independently from each other to heat the die or mold to the elevated temperature as they provide to the interior surface of the. matrix or mold with a desired temperature profile and the molding apparatus or installation includes a melting apparatus for forming a molten metal charge for use in molding the metal apparatus in the molding assembly, the device. The fusion device includes a heating arrangement for heating a precursor of the molten charge to a temperature at which the molten charge is formed from the precursor, the fusion apparatus having the capacity to produce a full charge of molten metal having a volume that is made correspond or match the capacity or volume of the die or mold, such that the molding of a single artifact of the die or mold completely consumes a full molten charge produced by the fusion apparatus when the fusion apparatus is put into operation at full capacity, the heating arrangement of the fusion apparatus is an induction heating arrangement comprising at least one induction coil. The induction heating arrangement of the molding assembly may be in the form of an induction heater of variable frequency. The assembly may include a supply of purge gas connected to the die or mold to supply a purge gas into the die or mold. The matrix or mold can be a disposable matrix, such as a matrix or sand molding mold. Instead, the matrix or mold may comprise a reusable die or mold. The reusable die or mold can be a metal die or mold, preferably a steel die or mold. In particular, the matrix or mold can be a reusable multi-core segmented metal matrix or mold.

In the case of a reusable matrix or mold, a matrix or segmented multi-core mold comprising two or more cores or segments can be a matrix or mold. In particular, the matrix or mold may comprise a core or segment superior to which the solidified artifact remains detachably attached at the end of the molding. The core or upper segment may include or be associated with release means to release the artifact therefrom. In this case, the die or mold will also commonly comprise a load core or core and a ring of side cores associated with pistons, such cores or side segments giving the die or mold its segmented character. In particular, the reusable matrix or mold can be hydraulically operable, with respect to the pistons of the side cores and with respect to the lifting of the upper core and the molding of the remaining cores to bring the molding into contact with pins forming the means of release. The die or mold will commonly have a discharge orifice for use in filling or unloading the die or mold with molten light metal. In one embodiment of the invention, the die or mold has its loading orifices provided through the bottom or front core to load or fill the die or mold from below. In a preferred embodiment, the reusable die or mold is hydraulically operable and has a bottom or face core provided with a loading orifice. metal to load the matrix or. mold with molten metal from below. The induction heating arrangement may include two or more induction coils, operable independently from each other to have a desired temperature profile in the die or mold. The molding assembly can be of permanent construction as part of an interaction, being constructed to remain more or less permanently in situ, in a production facility for molding light metal artifacts. Instead of this and preferably, the molding assembly is not of permanent construction, being movable constant from one apparatus of one production facility to another. Preferably, the melting apparatus is sized to melt metal charges that are matched in size with the size of. the matrix or mold, in such a way that the molding of the artifact in the matrix or mold consumes a whole load. In each case, wherein the array or mold arrangement, on the one hand, and the melting apparatus on the other hand, include one or more induction heating coils, the induction coils can be electrically connected to a power supply source. for them. The fusion apparatus may alternatively be movable relative to the molding assembly between a loading position, wherein the loading of the melting apparatus with a precursor of the molten charge takes place and a filling position wherein the transfer of a load melting of the melting apparatus or melting installation to the molding assembly takes place. Thus, the molding apparatus or installation may include rails, the fusion apparatus is mounted via wheels on the rails, the wheels may roll along the rails during reciprocating movement of the fusion apparatus relative to the molding assembly. The molding apparatus or installation may include two or more of the molding assemblies and the same number of the melting apparatuses, the molding assemblies share a common heating management source and the fusion appliances share a heating power source common, for the molding of artifacts in respective molding cycles that are sufficiently out of phase to allow such sharing. In other words, the molding apparatus or installation may include a plurality of the molding assemblies and the same plurality of fusion apparatus, each molding assembly is associated with only one of the fusion apparatuses and each fusion apparatus is associated With a single molding assembly, the molding assemblies share a common electric heating power source and the fusion appliances share a common electric heating power source.

The arrangement of the installation is particularly appropriate for the case where the heating arrangement for the melting apparatus or installations is also an induction heating arrangement, the heating power sources are sources of electrical power. The invention will now be described by way of non-limiting illustrative example with reference to the attached schematic figures. In the Figures, Figure 1 shows a detailed schematic side elevational view of the various components of a molding assembly according to the invention for molding a light metal artifact according to the process of the invention; Figure 2 shows a detailed schematic side elevational view of the various components of a melting apparatus for use with the molding assembly, to form a molten metal melt charge of light metal, for use in the process of the invention; Figure 3 is a three-dimensional view of a molding apparatus or installation according to the invention, for molding light metal artifacts, according to the method of the invention; Figure 4 is a three-dimensional view of a molding installation according to the invention and comprising two molding apparatus or installations of Figure 3 for molding light metal artifacts according to the method of the invention; Figure 5 shows a series of views in simplified schematic side elevation of the molding apparatus or installation of Figure 3, illustrating the method of molding a light metal device in the form of a magnesium alloy wheel, in accordance with the invention, using the molding apparatus or installation of Figure 3 and Figure 6 is another series of simplified schematic side elevational views of the molding apparatus or apparatus of Figure 3, further illustrating the method of molding an artifact of light metal in the form of a magnesium alloy wheel illustrated by Figure 5. Referring first to Figure 1 of the drawings, reference number 10 generally refers to a molding assembly for molding a light metal artifact, according to the invention. The molding assembly 101 comprises a die or mold 12 for molding a light metal artifact in the form of a magnesium alloy wheel and also comprises an induction heating arrangement 14 surrounding the die or mold 12. The die or mold 12 is a multi-core or segmented reusable steel die or mold comprising an upper core 16 to which a solidified artifact remains removably attached at the end of the molding process, a bottom or load core 18 having a hole or centrally located load passage 20 provided therethrough for loading or filling the die or mold 12 from below and a segmented ring of four side cores 22 associated with respective pistons 241, the side cores 22 give the die or mold 12 its segmented character. The die or mold 12 is put into operation hydraulically, with respect to the pistons 24 of the side cores 22 and with respect to the lifting of the upper core 16 and any molding of light metal attached (not shown) up and away from the remaining nuclei. The upper core 16 is associated with release means (not shown) to release the artifact thereof at the end of the molding process. The heating arrangement 14 comprises six windings forming induction coils 25, 26, 27, 28, 29 and 30, operable independently of each other, to obtain a desired temperature profile in the die or mold 12. The molding assembly 10 also it includes a supply of purge gas schematically shown by dashed line 31, for supplying SF6 / C02 purge gas to the die or mold 12 before and during the molding process. Referring now to Figure 2 of the drawings, reference number 40 generally refers to a melting apparatus to form a light metal melt charge., according to the invention. The fusion apparatus or installation 40 comprises. a steel cylinder sleeve or cylinder 42 of low or medium hollow carbon content of circular cross-section to contain a molten charge of light metal and also to facilitate the heating of a precursor of the light metal charge, an induction heating arrangement 44 comprising an induction coil 46 for heating the contents of the cylinder or sleeve 42 to form a molten charge and a molten metal transfer assembly 48 for transferring a molten charge of light metal from the cylinder or sleeve 42 to the die or mold 12 in which an artifact is molded. The melting apparatus 40 also includes a supply of inert gas 50 for supplying argon gas to the interior of the cylinder or sleeve 42, such that the fusion of the light metal charge takes place under a largely inert atmosphere and also to provide cooling to the lower end or base of the cylinder or sleeve 42 to form a secondary seal therefor as hereinafter described. In service, the induction coil -46 is mounted on the metal transfer assembly 46, the coil 46 is connected to the barrel 62 surrounding the cylinder or sleeve 42 to heat the contents thereof. The transfer assembly 48 comprises a telescopically movable multi-stage piston arrangement 52 for use in raising the cylinder or sleeve 42 to be fixedly engaged with the periphery of the loading orifice 20 of the die or mold 12, prior to filling the matrix or mold 12 with a melt charge of the cylinder or sleeve 42. the multi-stage piston arrangement 52 incorporating a central piston comprising three telescopic piston rods 54, 55, 56, the central rod having a piston head 58 provided with A conical sealing surface 59 for sealingly engaging the periphery of the orifice 20 to the die or mold 12 when an entire fused charge in the cylinder or sleeve 42 has been transferred from the cylinder or sleeve 42 to the die or mold 12. The multi-stage piston arrangement 52 includes a variable speed and force controller (not shown) to control the speed of movement thereof and also for control The upward force exerted by the piston head 58 on a molten charge on the sleeve cylinder 52 and on the die or mold 12, when the piston head 58 is sealingly coupled to the periphery of the loading orifice 20 of the die or mold 12. Thus, in use, the cylinder or sleeve 42 is supported on the transfer assembly 48, such that the multi-stage piston arrangement 52 is movable within the interior of the cylinder or sleeve 42 in engagement slidable and sufficiently sealed therewith to allow a molten charge in the cylinder or sleeve 42 to be pushed up and out of the cylinder or sleeve 42 after upward movement of the piston rods 54, 55, 56, to transfer and inject the molten charge to the matrix or mold 12. The transfer assembly 48 also comprises a plurality of concentric barrels 60, 61, 62, 63 and 64 of different diameters. The barrels 60, 61, 62, 63 and 64 are telescopically vertically movable relative to each other and interconnected. The barrel 60 is the bottom barrel and has wheels 66 for running on rails 67 that form part of the molding installation of Figures 4-6 to alternately move the fusion apparatus or facility 40 between a loading position where the loading of the cylinder or sleeve 42 with a precursor of a molten charge takes place and a filling position wherein the melting apparatus 40 is in alignment with the loading orifice 20 of the die or mold 12 of the molding assembly 10, to allow that a molten charge formed by melting a precursor thereof in the cylinder or sleeve 42 is transferred thereto to the die or mold.12, filling it by this commonly with the molten charge. The barrel 64 is the upper barrel and provides a circumferentially extending upward facing support ring having a slit (not shown) for sealingly engaging the lower end of the cylinder or sleeve 42 therein. The barrel 62 in turn provides a circumferentially extending upward facing support ring on which the induction coil 46 is supported when it is placed on the cylinder or sleeve 42 to surround it. In addition to the seal provided by the groove on the barrel 64, the argon gas supplied by the gas supply 50 provides cooling to the lower end of the cylinder or sleeve 42 during melting of the molten charge precursor, allowing part of the molten charge to flow. formed solidifies in an area between the piston arrangement 52 and the upper barrel 64 and at the lower end of the cylinder or sleeve 42, thereby providing a secondary seal which is formed of solidified light metal from the molten charge. Referring now to Figure 3 of the Figures, the reference number 70 generally refers to a molding apparatus or installation for molding light metal artifacts, according to the invention. The same reference numbers are assigned to the same parts as in Figures 1 and 2, unless otherwise specified. The molding apparatus or installation 70 comprises a molding assembly 10 as described above and a fusion apparatus 40 also as described above. The molding apparatus or installation 70 also includes a hydraulic controller 72 for the die or mold and a hydraulic controller 74 for the fusing apparatus 40. The upper core 16 is associated with release means (not shown) for releasing the artifact therefrom. at the end of the molding process. The molding apparatus or installation 70 also includes a central processing unit (CPU) 76 to verify heating of the induction heating arrangement 14 to obtain the desired temperature profile and also to provide feedback control to respective power supplies 92 and 94 (Figure 4) for the same. The molding apparatus or installation 70 also includes rails (not shown but seen at 67 in Figure 2) on which the transfer wheels 76 of the metal assembly 48 of the fusion apparatus 40 can run. Thus, the melting apparatus 40 is movable alternately in relation to the array array 12 between a loading position (as shown in Figure 3) where the loading of the melting apparatus 40 where a precursor of the molten charge takes place and a filling position (see Figures 5 and 6) wherein the transfer of a molten charge from the melting apparatus. The molding apparatus or installation 70 also includes rails (not shown but seen at 67 in Figure 2) on which the wheels 66 of the metal transfer assembly 48 of the fusion apparatus 40 can run. Thus, the melting apparatus 40 is movable alternately in relation to the array array 12 between a loading position (as shown in Figure 3) where the loading of the melting apparatus 40 with a precursor of the molten charge takes Place and a filling position (see Figures 5 and 6) wherein the transfer of a molten charge from the melting apparatus 40 to the die or mold 12 of the molding assembly 10 takes place. Referring now to Figure 4 of the drawings, the reference number 90 generally refers to a development of the apparatus or installation 70 in the form of a molding installation. The molding installation 90 comprises two molding apparatus or installations 70, each comprising a molding assembly 10 having a die or mold 12 in which the molding of the artifact is effected and having a fusion apparatus 40 for inducing fusion of a load of light metal. Molding installation 90 also includes a fusion induction heating power supply 92, for example of 100 kW, to separately supply energy to each of the two fusion devices 40, a matrix induction heating power supply 94, also for example 100 kW, to separately supply energy to each set molding 10, a cooling tower (not shown) to provide cooling fluid and a gas supply control unit 96 for supplying purge gases to the molding assembly 10 and also to the fusion apparatus 40. It will be appreciated that the molding facility 90 allows two artifacts to be molded simultaneously using molding cycles that are out of phase, the fusion apparatuses 40 that share the common induction heating power supply 92 and the molding facilities 10 that share the source of common induction heating power 94. The molding of the artifacts then takes place in respective molding cycles which are their sufficiently out of phase to allow such a compartment. It will thus be appreciated that the molding installation 90 can be put into operation almost continuously, in that the molding apparatus or installations 70 can be used in an alternating base, one has its fusion apparatus 40 in its filling position and is used for molding while the other has its fusion apparatus 40 in its loading position and is loaded with a precursor of the light metal and is prepared to be moved alternately to its filling position as soon as the molding process in the other Molding apparatus or installation 70 is completed. Referring now to Figures 5 and 6 of the drawings, the use of the molding apparatus or installation 70 described above is illustrated with reference to the molding of a light metal device in the form of a 100 magnesium alloy wheel, using a precursor in shape of a yew or ingot. 102 preformed from a magnesium-aluminum-zinc alloy known in the art as AZ91. The yew or ingot 102 is placed on the piston arrangement 52, with the associated fusion apparatus 40 in its loading position. The cylinder or sleeve 42 is placed on the shingle or ingot 102, such that the lower end of the cylinder or sleeve 42 is sealingly engaged with the slit on the upper barrel 64 of the metal transfer assembly 48. The coil induction 46 is connected to barrel 62 of the transfer set. metal 48, in such a way that the positioning of the cylinder or sleeve 42 and the shingle or ingot 102 in position acts to surround them by the coil 46. The molding assembly 10 is prepared for molding by folding down the upper core 16, in such a manner which engages with the bottom or face core 18. The ring of lateral core segments is then placed in position, using its pistons 24, to close the die. Purge gas in the form of an SFd / C02 alkaline flux gas mixture comprising 0.2% by volume of SF6 is fed to the matrix or mold 12 and the matrix or mold 12 is heated using the induction coils 25, 26, 27 , 28, 29 and 30 by electrical power fed from the induction heating power supply 94 using a preselected frequency, until the die or mold 12 obtains a required operating temperature and has a desired temperature profile. The heating rate can be altered by changing the power input of the power supply 94 and / or by changing the frequency of the same, a higher frequency results in a higher heating rate and the coils 25, 26, 27 , 28, 29 and 30 can be put into operation selectively with different power supplies to them, to obtain the temperature profile. The melting apparatus 40 is moved alternately with the help of the wheels 66 on the rails 67 of the molding apparatus or installation 70, from the loading position where the loading of the cylinder or sleeve 42 with the yew or ingot 102 of a molten charge Alloy of AZ91 takes place, to a filling position wherein the melting apparatus 40 is in alignment with the loading orifice 20 through the bottom or face core 18 of the die or mold 12. The cylinder or sleeve 42 is sealingly coupled with the bottom surface of the face bottom or core 18 when raising the barrel 64 hydraulically, which also seals the cylinder or sleeve 42 to the barrel 64. The cylinder or sleeve 42 is purged by a purge gas of SF6 / C02. The yew or ingot 102 is melted under an atmosphere provided by the purge gas introduced to the cylinder or sleeve 42 by the supply of gas 50, until a molten charge of AZ91 alloy is formed. Argon is then used to provide a cooling atmosphere for the cooling of the molten charge at the end. bottom of the cylinder or sleeve 42 to form a secondary seal in the form of a more or less semi-solid or solidified portion or flute of the light metal (not shown). Once the desired operating temperature and temperature profile have been obtained in the die or mold 12 and the die or mold 12 has been locked under pressure with the help of the pistons 24 by means of the hydraulic control 72, the supply of gas to the cylinder or sleeve 42 is cut off and the molten charge is transferred under cylinder pressure or sleeve 42 to the die or mold 12 by means of the piston arrangement 52, thereby filling the die or mold 12 with the molten charge. Before and during the injection of the molten charge into the die or mold 12, the die or mold 12 is purged with the aforementioned SF6 / C02 alkaline purge / flux gas • 15 by means of the control unit 96 of the gas supply , such gas also protects the molten surface from the molten charge in both the sleeve 42 and when it enters the die or mold 12. The piston head 58 is sealingly blocked against the periphery of the loading orifice 20 and partially enters the charging hole 20 to increase the pressure on the molten charge in the die or mold 12. The die or mold 12 is allowed to cool and the melting apparatus 40 is separated from the die or mold 12. Then the melting apparatus 40 is moved alternately back to its loading position. Then the die or mold 12 is opened by hydraulically separating the segment ring of side cores 22 from each other with the help of the pistons 24 and the upper core 16 with the solidified wheel 100 appended thereto, it is lifted, using the controller. 72. Then the wheel 100 is separated or released from the upper core 16 by allowing downwardly directed bolts forming part of the release means (not shown) to push the wheel 100 downwardly during the "lifting of the upper core 16. The arrangement piston 52 is lowered and then the barrels of the assembly 20 are retracted, releasing cylinder or sleeve 42 and the solidified portion or spreader (not shown) of the molten charge that formed the secondary seal for the cylinder or sleeve 42. Then the cylinder or used sleeve 42 is cleaned and repositioned on the transfer assembly 48 in preparation for the molding of a new wheel 100. However, it will be appreciated that a cylinder or sleeve Different 42 can instead be used to avoid waste of production time and also to minimize the possibility of cross contamination. It is an advantage of the invention that the molding apparatus or installation 70 need not necessarily be of a permanent construction, being movable from one production facility to another with ease .. Thus, the molding apparatus or installation 70 can be adjusted in a manner not expensive near an end user of the artifacts to be molded, thereby reducing transportation costs and the like. It is also a particular additional advantage of the invention that the induction heating of the matrix or mold 12 by the heating arrangement comprising the six induction coils 25, 26, 27, 28, 29 and 30, operable independently from each other, allows that a desired temperature profile is obtained in the die or mold 12 before the molding step, thereby having a desirable consequential effect on the solidification rate of the various portions of the artifact, such as wheel 100, thereby reducing efforts in the solidified device (wheel 100). Obtaining the desired flow distances for the complete filling of the matrix or mold 12 are also allowed. It is still a further advantage of the present invention that the molding apparatus or installation 70 does not require much space to be erected. For example, the molding apparatus or installation 70 as described above requires only a floor space of approximately 20-30 m2. The present process also offers other cost benefits such as the fact that the power source only has to be fed to the molding apparatus or facility 70 immediately before molding and can be turned off at the end of the molding of a single device, without affecting adversely affect the process or its efficiencies. The case of an energy interruption during the molding process using the method and apparatus or molding installation 70 of the present invention, it will be appreciated that the losses need not be greater than the loss of the molten charge in the cylinder or sleeve 42, which comprises the single ingot or ingot 102, as compared to a typical casting where the process is continuous and large amounts of metal they have to be melted at any point in the given time, all of which can solidify in the case of a power interruption. Indeed, the losses can in principle be completely avoided by simply remelting the contents of the cylinder or sleeve 42, when the power supply is restored. It is still an additional advantage of the process according to the present invention that the die or mold 12 of the molding assembly 10 does not require a re-run in order to obtain the optimum process conditions. The desired molding temperature profile can easily be obtained by selectively controlling the energy fed to each of the coils 25, 26, 27, 28, 29, and 30. The fact that the process does not require a cycle or run cycles means that a particular number of yews or ingots 102, which prevent any energy failures, must produce an equivalent number of wheels 100, with reduced waste arising from rejection artifacts and improved quality control.

Claims (19)

1. CLAIMS 1. A Process for molding a metal device by loading a die or mold with molten metal and causing o. allow the metal to solidify in the matrix or mold to form the artifact, the process includes, the stage, before loading the matrix or mold with the molten metal, heating the matrix or mold by induction heating at a temperature high, the charge takes place with the matrix or mold at the elevated temperature, the process is characterized because, in combination: the induction heating is used to provide the surface of the interior of the matrix or mold with a desired temperature profile, by which the inner surface of the matrix or mold has different parts or zones at different temperatures from each other, in contact with the molten metal charged to the matrix or mold, thereby promoting desired cooling and solidification rates in different parts of the metal charged to the die or mold, and the charge of the die or mold is from a fusion apparatus that has the capacity to produce a full charge of molten metal that is matched in volume with the capacity or volume of the die or mold, the charge of the die or mold is with enough molten metal to produce a single artefact and the charge acts completely to consume a full molten charge produced by the melting apparatus, the heating arrangement of the melting apparatus is an induction heating arrangement comprising at least one induction coil.
2. 2. The process according to claim 1, characterized in that it includes the step, before loading the matrix or mold, to purge the matrix or mold with a purge gas, the charge takes place under an atmosphere provided by the gas of purge.
3. 3. The process according to claim 2, characterized in that the purging is carried out both before and during the heating of the matrix or mold, the purge is discontinued before the charging takes place.
4. 4. The process according to any of the preceding claims, characterized in that the loading is carried out under pressure, acting to fill the matrix or mold to its full capacity.
5. 5. The process according to claim 4, characterized in that the charging is carried out by injection molding, at an intermediate pressure in the range of 50 kPa-30 MPa.
6. The process according to any of the preceding claims, characterized in that it includes using as the metal a metal selected from the group consisting of aluminum, magnesium, lithium, zinc and alloys thereof.
7. 7. The process according to claim 6, characterized in that it includes using as the metal a light metal selected from the group consisting of magnesium, aluminum and alloys thereof.
8. 8. The process according to claim 7, characterized in that the molding is of a light metal device in the form of a motorized vehicle wheel.
9. 9. The process according to any of the preceding claims, characterized in that the molding is of an artifact of. metal in which the part of the solidified artifact that is furthest from the surface of the artifact is spaced from the nearest part of the artifact surface by a spacing of 0.75 - 15 mm, the artifact has a mass of 0.25 - 30 kg.
10. 10. The process according to any of the preceding claims, characterized in that the charge of the matrix or mold is from a fusion apparatus that is alternately movable in relation to the matrix or mold, the process includes making the apparatus move alternately. fusion between a loading position where it is charged with a precursor of the molten charge and a filling position wherein the molten charge is transferred from the fusion apparatus to the molding assembly.
11. 11. The process according to any of the preceding claims, characterized in that the molding is carried out in a plurality of dies or molds, each associated with a single melting apparatus from which it is loaded, each melting apparatus is associated with a single die or mold and is electrically heated by heating by induction, a common power source is used to supply electrical power to the dies or molds for induction heating thereof and a common power supply is used to supply electrical power to the fusing apparatus.
12. 12. A apparatus or molding installation for molding metal artifacts, the apparatus or installation includes a molding assembly for molding a metal artifact, the molding assembly includes a mold or mold for molding the artifact and the assembly includes an induction heating arrangement , the induction heating arrangement includes at least one induction coil that surrounds the matrix or mold for heating the matrix or mold to an elevated temperature before molding the apparatus, the apparatus or installation is characterized in that, in combination: the induction heating arrangement includes a plurality of at least two of the induction coils which are operable independently from each other to heat the die or mold to the elevated temperature as long as they provide the surface of the interior of the die or mold with a desired temperature profile, and the molding apparatus or installation includes a fusion apparatus for forming a molten metal charge for use in molding the metal artifact in the molding assembly, the The melting apparatus includes a heating arrangement for heating a precursor of the molten charge to a temperature at which the molten charge is formed from the precursor, the fusion apparatus having the capacity to produce a full charge of molten metal having a volume that it is matched or 10 corresponds to the capacity or volume of the die or mold, such that the molding of a single artifact in the die or mold completely consumes a full molten charge produced by the fusion apparatus when the fusion apparatus is put into operation at full capacity, the heating arrangement of the • Fusion apparatus is an induction heating arrangement comprising at least one induction coil.
13. The apparatus or installation according to claim 12, characterized in that the induction heating arrangement of the molding assembly is in 20 shape of a variable frequency induction heater.
14. The apparatus or installation according to claim 12 or claim 13, characterized in that it includes a purge gas supply line connected to the die or mold to supply a purge gas into the interior of 25 the matrix or mold.
15. 15. An apparatus or installation according to any of claims 12-14 inclusive, characterized in that the matrix or mold is a reusable multi-core segmented metal matrix or mold.
16. 16. The apparatus or installation according to claim 15, characterized in that the reusable matrix or mold is hydraulically operable and has a bottom or face core provided with a metal loading orifice for loading the matrix or mold with molten metal from down.
17. The apparatus or installation according to any of claims 12-16 inclusive, characterized in that the fusion apparatus is movable alternately in relation to the molding assembly between a loading position wherein the loading of the fusion apparatus with a precursor of the molten charge takes place and a filling position wherein the transfer of a molten charge from the melting apparatus to the molding assembly takes place.
18. 18. The apparatus or installation according to claim 17, characterized in that it includes rails, the fusion apparatus is mounted via wheels on the rails, the wheels can roll along rails during reciprocating movement of the fusion apparatus in relation to the molding set.
19. 19. The apparatus or installation according to any of claims 12-18 inclusive, characterized in that it includes a plurality of the molding assemblies and the same plurality of fusion apparatus, each molding assembly is associated with the fusion apparatus and each melting apparatus is associated with a single molding assembly, the molding assemblies share a common electric heating power source and the fusion appliances share a common electric heating power source.