US3619866A - Magnetizable mass casting device - Google Patents

Magnetizable mass casting device Download PDF

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Publication number
US3619866A
US3619866A US22125A US3619866DA US3619866A US 3619866 A US3619866 A US 3619866A US 22125 A US22125 A US 22125A US 3619866D A US3619866D A US 3619866DA US 3619866 A US3619866 A US 3619866A
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Prior art keywords
mold
casting
magnetizable
pattern
forming
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US22125A
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Richard Hofmann
Adalbert Wittmoser
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C33/00—Moulds or cores; Details thereof or accessories therefor
    • B29C33/38—Moulds or cores; Details thereof or accessories therefor characterised by the material or the manufacturing process
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/06—Permanent moulds for shaped castings
    • B22C9/061—Materials which make up the mould
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C41/00—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor
    • B29C41/02—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor for making articles of definite length, i.e. discrete articles
    • B29C41/04—Rotational or centrifugal casting, i.e. coating the inside of a mould by rotating the mould
    • B29C41/042—Rotational or centrifugal casting, i.e. coating the inside of a mould by rotating the mould by rotating a mould around its axis of symmetry
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/0302—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity characterised by unspecified or heterogeneous hardness or specially adapted for magnetic hardness transitions
    • H01F1/0311—Compounds
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/0302—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity characterised by unspecified or heterogeneous hardness or specially adapted for magnetic hardness transitions
    • H01F1/0311—Compounds
    • H01F1/0313—Oxidic compounds
    • H01F1/0315—Ferrites
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S425/00—Plastic article or earthenware shaping or treating: apparatus
    • Y10S425/033—Magnet

Definitions

  • a mold of particulate material including magnetizable particles is made shape-retaining by subjecting the shaped mold to a magnetic field of suicient strength to tix the position of the particulate magnetizable mold-forming material.
  • the present invention is concerned with a casting method and more particularly lwith a mold including a cavity into which a mass to be cast, for instance liquid metal or synthetic plastic material may be introduced.
  • a mold-forming particulate material consisting essentially of natural or synthetic sand is utilized and the pattern is embedded therein.
  • synthetic plastic materials may be used as binder for the sand or the like.
  • a special casting method provides for patterns of foamed polystyrene and the like, for instance patterns made of the material commercially available under the trade name Styropor. Such pattern is not removed from the mold but retained therein and, upon introduction of the material to be cast, due to the high temperature thereof, the pattern will be subjected to combustion and will be gasied substantially without leaving any residue. The combustion gases pass through the interstices in the sand mold or the like.
  • This method is widely used because making and storage of the pattern of foamed polystyrene or the like can be carried out in an extremely economical manner. However, obviously, each pattern can be used only once.
  • a pattern is introduced into a particulate mass of mold-forming material so as to form a mold cavity therein.
  • the mold-forming material includes particles of magnetizable material in an amount sufficient to rigidify the mold-forming material while the same is exposed to a magnetic field, so that the mold cavity formed in the mass by introduction of the pattern will be maintained and the thus-formed mold will remain shape-retaining during the entire length of exposure thereof to the magnetic lield.
  • the thus formed mold is then subjected to the magnetic eld so as to become rigidified, prior to introduction of the material to be cast into the mold and at least during the initial period of introduction of the material to be cast.
  • the casting arrangement for carrying out the abovedescribed method broadly comprises a casting box, activatable magnetic field-forming devices such as induction coils located adjacent the casting box, preferably surrounding the same, and possibly also including an induction coil in the interior of the casting box, depending on the shape of the article to be cast, and a magnetizable mass of particulate, mold-forming material located in the casting box and adapted to be magnetized so as to become shape-retaining while being subjected to the magnetic tield.
  • activatable magnetic field-forming devices such as induction coils located adjacent the casting box, preferably surrounding the same, and possibly also including an induction coil in the interior of the casting box, depending on the shape of the article to be cast
  • a magnetizable mass of particulate, mold-forming material located in the casting box and adapted to be magnetized so as to become shape-retaining while being subjected to the magnetic tield.
  • FIG. 1 is an elevational cross-sectional view of a casting arrangement in accordance with the present invention in which the pattern may be removed after formation of the mold cavity;
  • FIG. 2 is a cross-sectional elevational view of a casting arrangement or device in which the pattern consists of material which will be gasied upon introduction of the molten casting material;
  • FIG. 3 is a cross-sectional view taken along line III- III of FIG. 1;
  • FIG. 4 is a cross-sectional elevational view of a device for producing tubular casting in accordance with the present invention.
  • FIG. 5 is a schematic elevational view in cross section of a casting arrangement according to the present invention and including means for producing a plurality of magnetic fields in which the lines of magnetic force may cross sect each other;
  • FIG. 6 is a schematic elevational view in cross section of a casting arrangement according to the present invention, wherein the casting box comprises a plurality of segments of different cross sectional dimensions;
  • FIG. 7 is an elevational cross-sectional view of a permanent mold arrangement in accordance with the present invention.
  • FIG. 8 is a cross-sectional longitudinal view of an arrangement for centrifugal casting in accordance with the present invention.
  • the mass which is to be shaped by the pattern embedded therein and which after removal of the pattern will define the mold cavity which is to be filled with a material to be cast must be of a certain consistency or, in other words, must be of such consistency as to be shape-retaining once the mold cavity has been formed therein.
  • the present invention provides that the pattern is embedded in a mas of magnetizable particles of relatively small grain size and that this mass, after the mold cavity has been defined therein by introduction of the pattern (or by centrifugal force as will be described further below), is prior and possibly also during and after the casting, subjected to at least one magnetic field, such as the electric field produced -by induction, whereupon the pattern, depending on the type thereof is removed from the shaped mold which is rigidiiied by being exposed to the magnetic field.
  • Removal of the pattern may be carried out in conventional manner, for instnace by physically removing the pattern, or by utilizing a pattern which will be -gasitied upon contact with the casting mass which is introduced into the mold cavity while the latter is maintained in a shape corresponding to that of the pattern by application of the induction field.
  • the magnetizable particles which form at least a portion of the mold-forming particulate mass preferably will have a particle size of below 0.7 mm. and most preferably between about ⁇ 0.1 and 0,5 mm. In most cases it is preferred to utilize substantially spherical particles, however, in certain cases-as will be described further below, it is preferred to utilize elongated particles such as needles or chips.
  • magnetizable materials which can be made available in the form of small particles and which are capable of withstanding elevated temperatures to which they might be exposed during the casting process may be utilized. These include primarily natural magnetizable iron, and nickel alloys, as well as FeO and magnetizable ferrites.
  • a magnetic iield is formed which will rigidify the particulate molding material in the shape determined by the pattern introduced into the casting box and at least partially embedded in the molding or moldforming material.
  • the mold cavity, corresponding to the shape of the pattern is then formed either by removal of the pattern or by combustion of the latter.
  • the magnetizable material such as iron or another magnetizable heavy metal or alloys thereof, or a magnetizable mineral such as magnetite will be utilized in the form of needle-shape bodies or in sandlike configuration, or in the form of chips, for instance filings or borings, preferably within the above-described size limitations.
  • the molten plastic material will have formed a semi-solid or solid skin along the mold cavity-forming wall of the mold material which has been rigidified by being exposed to a magnetic field, so that, due to the formation of such skin, heat demagnetization of the magnetizable particles will no longer affect the shape of the body being cast.
  • the needle-shaped particles will have a length equal to between 5 and 20 times their diameters and the average diameter of the needles preferably will be below 0.7 mm. and most preferably between about 0.1 and 0.5 mm.
  • mold-forming material a mixture of ma gnetizable particles and non-magnetizable particles such as mineral sand.
  • the admixed sand is not magnetizable, however, it will be maintained in fixed position by the surrounding magnetizable particles so that the entire mixture will be rigidi-hed upon exposing the same to a magnetic field which directly affects only the magnetizable portion of the mixture.
  • Sand being of much lower heat conductivity than the magnetizable particles, particularly if the latter consists of metal or alloys, will permit the desired control of heat transfer from the molten casting material.
  • the mold forming particulate material according to the present invention possesses an excellent permeability for gases. This may be particularly due to the fact that no compacting of the moldforming material such as is conventionally carried out in the case of sand molds, will be required.
  • the method of the present invention is excellently suitable for forming molds by means of combustible patterns, for instance patterns of Styropor or similarly acting foamed synthetic materials, which patterns are retained in the mold and will be gasified or burned practically without residue upon being contacted with the molten casting mass which eventually will completely till the space previously occupied by the combustible pattern.
  • combustible patterns for instance patterns of Styropor or similarly acting foamed synthetic materials
  • the electromagnetic induction field which is required for rigidifying the magnetizable particles-containing mass is preferably produced by means of induction coils which are so arranged as to surround at least the side wall of the casting box, preferably along its entire height and which may also extend outwardly of the bottom and top portion of the casting box.
  • the casting box is of relatively great height, i.e ⁇ if the mold cavity and the pattern are of relatively great height, it is preferable to control the solidiiication of the molten casting material which is introduced into the mold cavity by subdividing the induction lield into annular sections which preferably are individually controllable, for instance by suitable diiferentiation in the structure of the correlated induction coils or by separate control of the current flowing through the induction coils corresponding to the respective sections.
  • the casting box of superposed sections which may be of different cross-sectional dimensions, preferably so that the thickness of the mold-forming material between the pattern and the wall of the casting box will remain more or less uniform, in other words, the dimensions of the individual sections of the casting box would be correlated in this case to the cross-sectional dimensions of the portion of the pattern which will be located in the respective section of the casting: box.
  • the moidforming particulate material may consist of a mixture of magnetizable, non-magnetizable particles. Generally, the proportion of non-magnetizable particles should not exceed about 40% of the Weight of the mixture.
  • a mixture of 95% magnetizable and non-magnetizable constituents may be advantageously utilized, for a wall thickness of between 12 and 25 mm.
  • the proportion of non-magnetizable constituents may be increased, for instance to a mixture of 75% magnetizable and 25% non-mangetizable constituents, and for relatively thin molds such as molds having a wall thickness of less than l2 mm., a mixture of 60% magnetizable and 40% non-magnetizable particles may be utilized.
  • the magnetic or induction fields may be controlled in sections thereof depending on the type of material to be cast and its temperature, its degree of solidification and/or the type of magnetic mold-forming particles.
  • Such control of sections of the magnetic field may be carried out with respect to the length of time for which the respective magnetic field is to be maintained and/or with respect to its magnetic force or field strength.
  • the present invention also provides the application of a separating agent, coating or an agent for improving the surface characteristics of the cast body onto the mold cavity-forming face of the mold-forming material after the pattern has been removed from the mold.
  • a separating agent, coating or an agent for improving the surface characteristics of the cast body onto the mold cavity-forming face of the mold-forming material after the pattern has been removed from the mold may be applied in more or less conventional manner by dusting, brushing or spraying.
  • chromium or nickel to the surface of the cast body or to nitrate the same or to improve in other ways the quality of the solidifying skin of the cast body.
  • tellurium coatings or the like to the inner face of the mold in order to obtain a white hard surface structure, or to apply sulfurcontaining agents which will improve sliding of the cast body relative to the inner mold face.
  • the casting method of the present invention the forming of the mold as well as the casting in the mold while the mold-forming material is still under the inuence of a magnetic field and thus rigidified, can be controlled in a particularly advantageous manner by means of automatic control devices, particularly with respect to introduction of the molten casting material and the control of the induction or magnetic fields.
  • the present invention also encompasses a casting arrangement or device for carrying out the above-described method.
  • the casting device of the present invention comprises a casting box and at least one electrical coil preferably arranged about the perpendicular wall of a casting box for producing a magnetic field therein, as well as the mold-forming material consisting at least to a significant extent of particulate magnetic or magnetizable material of relatively small grain size in which the pattern may be embedded in order to form the mold cavity so that the molten casting material may be introduced into the latter.
  • Patterns of foamed polystyrene may also be advantageously replaced with patterns of polyurethane foam.
  • the cooling of the molten casting material in the mold cavity or the rate of solidication of the same may be controlled in conventional manner by the provision of cooling coils through which a cooling fluid, possibly water or air, passes, or other bodies replacing such coils, or by blowing gases, for instance, air through the porous mold.
  • the cooling coils or the like may be inserted into the mold cavity or may be outwardly arranged in a manner known to those skilled in the art.
  • the magnetizable mass of mold-forming material may be introduced into the casting box by means of a conventional conveying device, preferably while the casting box is subjected to vibration.
  • vibration may be automatically started by mold-forming material contacting the bottom of the casting box.
  • the pattern will have been inserted into the casting box so that the mold-forming material will now embed the pattern.
  • the vibrating device may be automatically shut of ⁇ r ⁇ and, simultaneously or after some delay, the magnetic field or fields may be formed so as to rigidify the particulate mass of magnetizable mold-forming material.
  • the schematic elevational cross-sectional view of a casting device comprises a casting box 1, electric coil 2 which surrounds the side Wall of casting box 1 and serves for creating a magnetic or induction field within the casting box 1, and particulate mold-forming material 3 in which an upwardly flaring substantially conical pattern 4 is embedded.
  • Moldforming material ⁇ 3 may consist ofi magnetizable small grain material, for instance of iron or other magnetizable heavy metals or magnetizable minerals and may be in the shape of sand-like granules, i.e. more or less spherical small particles, of needles, or of chips such as borings and filings.
  • an electromagnetic induction field will be created and will cause fixing of the particles of mold-forming material 3 which consists of magnetizable material so as to form a rigidified body of the mold-forming material 3.
  • the magnetic force replaces thereby the binding agent which is conventionally utilized in sand molding.
  • pattern 4 may be removed from the mold without thereby changing the configuration of the mold cavity which corresponds to the shape of the now removed pattern 4. Thereafter, while maintaining the induction field, liquid or molten casting materials may be poured or otherwise introduced into the mold cavity.
  • FIG. 2 differs from what is shown in FIG. 1 by the replacement of pattern 4 with pattern 5 made of Styropor or other foamed synthetic material which upon introduction of the hot molten casting material will be gasifed substantially without residue.
  • a molten casting mass is introduced having a temperature above the Curie point of the magnetizable portion of the mold-forming material, such as molten steel, then the points of needle 6 which are adjacent the mold cavity will loose their magnetic properties, however, even these needles 6 will be retained in their position because their oposite ends which are farther distant from the mold cavipty will only slowly be heated to a temerature above their Curie point.
  • the mold-forming mass 3 of a mixture of a magnetizable and of a nonmagnetic material, the latter for instance being mineral sand, which non-magnetic material due to its low heat conductivity will retard the rising of the temperature in radial direction from the mold cavity and thereby will also to some extent retard the solidication of the hot molten material in the mold cavity.
  • a magnetizable and of a nonmagnetic material for instance being mineral sand
  • the tine structure thereof may be controlled in a desired manner, and on the other hand, by retarding heat transfer from the wall of the mold cavity into the mold-forming mass, increase of the temperature at the points of needles 6 which are farther distant from the mold cavity also will be retarded.
  • cooling of1 the mold-forming material as well as control of the speed of solidication of the molten casting material may be carried out in conventional manner by means of] cooling coils 7 illustrated in FIG. 4.
  • FIG. 4 illustrates particularly utilization of the present invention in connection with the casting of tubular members.
  • a core portion 8 and in the interior thereof a further electric coil 9l which will produce an additional induction field.
  • This arrangement may also be correspondingly utilized in the case of divided hollow patterns. It may be advantageous to utilize for the moldforming material short lengths of wire or magnetizable materials of similar elongated shape which may felt so that the removal of the pattern or of the cast body will not affect the shape of the mold cavity.
  • an induction iield will also be formed between the coils 2', surrounding the top and bottom portions of casting box 1.
  • Coils 2' are particularly advantageous if the casting device is to be tilted in order to evenly distribute the mold-forming material and introducing the same into undercuts or other diiiicultly accessible portions of the pattern surface. This arrangement is also advantageous if, in view of the size of the pattern, during removal of the same frictional forces between the mold-forming material and the pattern as well as gravitational forces must be 8 counteracted by providing an ⁇ additional induction field.
  • FIG. 6 illustrates a casting device for casting bodies corresponding to a pattern of greatly varying crosssectional dimensions and relatively great height.
  • Such body for instance, may be a machinery housing.
  • the casting box of sections indicated as 1, 1a, 1b and 1c of differing crosssectional dimensions so that the distance of the pattern surface from the wall of the casting box will be substantially the same along the entire surface of the pattern.
  • the casting box is formed of annular sections whereby the diameter of each superposed section is smaller than that of the section directly below ⁇
  • the individual sections of the casting box are surrounded by induction coils 2, 2a, 2b and 2c of correspondingly varying diameters.
  • these induction coils are connected with control devices 10, 10a, 10b, and 10c which permit separate control of the current flowing through the induction coils associated with each of the sections of the casting box, corresponding to the cooling of the casting material in the mold cavity.
  • Vibrating of the casting box with the pattern and the mold-forming material therein may be accomplished, as schematically illustrated in FIG. 2, by supporting the casting box on a plate 21 which is subjected to vibration by operation of vibrator 22.
  • the casting box 1 is formed of individual elements which may be attached to each other whereby either or each of the elements is provided with an electric coil for forming of a magentic field, or has associated therewith at least part of such coil and the part coils may be connected to each other when connecting adjacent elements of the casting box.
  • the connecting of these elements to form the complete casting box may be carried out in per se known manner with conventional screw or guide pin devices.
  • the actuating of the electric coils and the introduction of the mold-forming material may be carried out by hand or with automatic control.
  • the method of the present invention will in many eases reduce the casting expenses by about 30% due to the shortening of the period of time required for forming the mold cavity.
  • the casting arrangement according to the present invention as well as the method of the present invention are suitable for series casting as well as for casting of individual pieces.
  • Mass production of cast bodies including cast tubular elements is conventionally carried out by ingot casting, pressure casting, continuous casting, centrifugal casting and the like.
  • the economic feasibility and the technological results of these and similar methods depend to a considerable extent on the useful lifespan of the permanent molds which ⁇ are u-tilized thereby.
  • the mold surface portions which are contacted by the molten casting material are frequently coated with materials such as finely granular refractory materials, which :are suspended in a liquid carrier such as water, alcohol and the like and which, for instance by spraying, brushing or immersion may be applied to the surface of the permanent mold.
  • a liquid carrier such as water, alcohol and the like
  • Such surface coatings or layers are connected with the disadvantage that the liquid carrier or solvent contained therein as well as binding agents which frequently are required generally produce gases or give off gases when contacted by the molten casting material.
  • most of these coatings contain quartz as the basic constituent, a certain health hazard is created by quartz particles which are separated during the casting process.
  • these dry coating materials usually have a lower specific gravity than the molten casting material and this difference in the specific gravities favors separation of surface particles form the coating or layer upon contact with the introduced stream of molten casting material. This again results in a most undesirable mixing of material of the coating layer with the casting material and in ⁇ an undesirable formation of the inner surface of the cast bodies formed by such centrifugal casting method.
  • the above-discussed difficulties and disadvantages may be overcome by forming a surface layer at the operative surface of the permanent mold 'which consists essentially of a particulate loose mass of magnetizable materials such as were described further above, for instance grains of iron, and to hold the particulate layer at the face of the permanent mold by a magnetic force, i.e. by applying a magnetic or induction field which will rigidify the particulate layer o-f magnetizable material.
  • a layer is formed interposed between the operative surface of the permanent mold and the molten casting material which is introduced into the same, which layer is free of metallurgically harmful constituents and will not form gas upon being exposed to the high temperature of the molten casting material.
  • the layer can be easily removed, by simply shutting off the magnetic field, and consists of physiologically harmless material. Due to the relatively low heat conductivity of the material of the layer, particularly if the layer is formed of magnetizable mineral material, as compared with the heat conductivity of the permanent mold which may be formed of metal, the interposed layer will also retard the heat flow from the molten casting material through the permanent mold and this is frequently desirable.
  • particles of the surface layer are incorporated in the molten casting material, such particles will be quickly dissolved in, for instance, molten ferrous material and thereby rendered harmless.
  • the last-described method of the present invention is of particular advantage for producing cast bodies in permanent molds by centrifugal casting.
  • the method may be used for forming a particulate layer on the operative surface of water cooled centrifugal molds, for instance in accordance with the De Lavand process, and the useful lifespan of the permanent mold Will be prolonged thereby and the surface quality of the cylindrical bodies, such as cast pipes produced in the process will be improved.
  • the magnetizable loose material may be introduced into a roating mold so that under the infiuence of centrifugal forces a layer of between and 10 mm. thickness (more or less) will be evenly formed on the operative face of the mold. Upon appplication of the magnetic field, this layer will be sufficiently rigidified so that the molten casting material may now be introduced into the thus-formed casting mold, without damaging the latter. After solidification of the metal melt in the mold, the magnetic field is shut off and the surface layer will thereupon trickle out of the mold thereby facilitating removal of the cast body.
  • the size of the magnetizable particles of which the surface layer is formed may be easily adjusted in per Se conventional manner so that the degree of roughness of the operative face of the magnetically fixed particulate layer will suffice to prevent under the prevailing operating conditions sliding of the melt along the operative surface of the magnetically fixed layer.
  • the particle size of the material of the surface layer preferably will be below 0.7 mm. and generally between 0.1 and 0.5 mm., however, in order to obtain a particularly smooth surface on the cast body, it is sometimes advisable to further reduce the particle size of the material of the surface layer, for instance to a particle size of between 0.1 to 0.03 mm.
  • the permanent mold may be made in conventional manner of various materials such as grey iron, steel, copper alloys, light metal, graphite and the like. If the material of the permanent mold is not per se magnetizable, it is possible to have the magnetic field penetrate through the permanent mold so as to cause fixing or rigidification of the particulate magnetizable layer at the operating surface of the mold.
  • Fire-resistant materials which may be admixed to the magnetizable particulate material further include aluminum oxide, olivine, chromite, and such refractor or fireresistant material may be applied in proportions such as described further above, whereby again the maximum proportion of non-magnetizable particles in the layer-forming mixture will depend on the desired thickness of the layer.
  • the permanent mold consists of magnetic or magnetizable materials such as cast iron or steel
  • magnetic adherence between the particles and the mold may follow.
  • the mold is formed for instance of aluminum, then, as described previously, coils for instance of copper may be arranged to surround the permanent mold so that upon passages of current through such coils a magnetic field will be created which acts through the mold wall onto the particulate material forming a layer thereon.
  • the last-described method may be used in connection with permanent mold casting, die casting, continuous Casting and centrifugal casting methods, in other words, it is applicable to practically all permanent mold casting processes.
  • FIGS. 7 and 8 illustrate casting arrangements with permanent molds.
  • a permanent mold 71 is surrounded by induction coils 72 which serve for forming a magnetic field which will cause adherence of layer 73 formed of magnetizable particulate material to the mold cavity 74- defining face 75 of permanent mold 71.
  • Permanent mold 81 is surrounded by induction coils 82 and the magnetic field formed by passing currents through induction coils 82 will cause adherence of layer 83 to the Operating inner face 84 of the permanent mold 81.
  • the configuration of the pattern is relatively complicated and uneven, it may be dicult, particularly in the case of hollow patterns, to stabilize the magnetizable particles at certain portions of the pattern surface.
  • reference numeral 51 denotes two larger solid bodies of magnetizable material which are arranged at the pattern surface in order to provide a more even surface for embedding in the particulate mold-forming material.
  • This problem can be overcome in a simple manner by spraying onto the pattern and possibly onto the entire pattern plate an either heat or cold hardenable material to which is applied prior to hardening thereof the magnetizable particulate material.
  • heat or cold hardenable materials are well known to those skilled in the art and include, for instance, furane resins, phenolic resins and also polyurethane resins which, by admixture of suitable hardeners also might be converted into a foam.
  • the thickness of the thus-formed hardened layer in which prior to hardening thereof particles of the magnetizable material have been incorporated preferably will be between about 0.5 and mm.
  • magnetizable particles which are located directly adjacent the surface of the pattern will be bound by forces other than magnetic forces and thus will not be influenced by the direction of lines of force emanating at these areas or zones from the mold cavity-forming magnetically xed particulate material.
  • a separating agent to the surface of the pattern prior to spraying the latter with the resin.
  • Certain silicones may be excellently suitable as separating agent and application of the separating agents will facilitate removal of the pattern so that the magnetic particles-containing resin binder will remain in contact with the par ticulate magnetizable mold-forming material and will form, at least in the zones to which it has been applied, the mold cavity-defining surface.
  • the binder material which will serve to x particulate magnetizable material by other than magnetic forces may also be a quick hardening synthetic resin or an organic silicate as Well as heat or cold hardenable inorganic materials, per se known to those skilled in the art.
  • the formation of the magnetic field has been described herein primarily as being accomplished by surrounding the casting box with at least one electric coil. However, in certain cases it has been found to be more advantageous to insert the casting box between the pole pieces of the yoke of a magnet. ln this manner, it is possible to obtain the required electromagnetic lixing of the magnetizable particles, or to produce or provide the required electromagnetic forces in casting boxes of varying sizes, Without requiring induction coils of different dimensions.
  • a casting arrangement comprising, in combination, a casting box comprising a plurality of superposed p0rtions of different cross-sectional dimensions; a magnetizable mass of particulate mold-forming material in said superposed portions', a removable pattern arranged within said mass of particulate mold-forming material in said casting box for forming a mold cavity in said material; and means for magnetizing said particulate mold-forming material so as to become shape-retaining to maintain said cavity after removal of said pattern, said means comprising a plurality of induction coils respectively surrounding said superposed portion of said casting box for forming upon actuation a magnetic field within each of said portions, and means for individually controlling the current owing through each of said induction coils.
  • a casting arrangement comprising, in combination, a casting box; a hollow core in said casting box; a magnetizable mass of particulate mold-forming material in said casting box about said core; a removable pattern arranged within said mass of particulate mold-forming material in said casting box about and spaced from said core for forming a mold cavity in said material; and activatable mgnetic field-forming means comprising at least one induction coil in said hollow core and at least one induction coil surrounding said casting box for magnetizing said particulate mold-forming material so as to become shape-retaining to maintain said cavity after removal of said pattern.
  • a casting arrangement comprising, in combination, a casting box; a magnetizable mass of particulate moldforming material in said casting box; a removable pattern arranged within said mass of particulate mold-forming material in said casting box for forming a mold cavity in said material; activatable magnetic field-forming means operatively associated with said casting box for forming upon activation a magnetic field within said casting box to magnetize said particulate mold-forming material so as to become shape-retaining to maintain said cavity after removal of said pattern; and cooling coils arranged in said casting box in contact with said magnetizable mass to prevent demagnetizing thereof during contact with hot metal cast in the arrangement.
  • a casting arrangement comprising, in combination, a casting box; a magnetizable mass of particulate moldforming material in the form of needles in said casting box; a removable pattern arranged within said mass of particulate mold-forming material in said casting box for forming a mold cavity in said material; and activatable magnetic field-forming means associated with said casting box for magnetizing upon activation said needleshaped particulate mold-forming material so as to become shape-retaining to maintain said mold cavity after removal of said pattern and to orient said needle-shaped particulate material to extend in longitudinal direction toward said field-forming means and so that the outer ends of said needles will be located distant from said mold cavity, whereby during casting of hot material into said cavity demagnetization of the needles will be prevented and the mass of mold-forming material will retain its shape.
  • a casting arrangement comprising, in combination, a casting box; a magnetizable mass of particulate material in said casting box; a pattern arranged within said mass of particulate material, said pattern consisting of material which gasiies upon contact with hot metal to be cast in the arrangement for forming a mold cavity in said particulate material; and means for magnetizing said particulate material to maintain said cavity upon gasifying the material forming said pattern.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Mold Materials And Core Materials (AREA)
  • Acyclic And Carbocyclic Compounds In Medicinal Compositions (AREA)
US22125A 1966-11-11 1970-03-31 Magnetizable mass casting device Expired - Lifetime US3619866A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DEH60967A DE1301439B (de) 1966-11-11 1966-11-11 Verfahren und Vorrichtung zum Herstellen einer Giessform mittels eines magnetisierbaren Werkstoffes
DEW0043734 1967-04-11
DEH0063131 1967-06-28

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US3619866A true US3619866A (en) 1971-11-16

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US (1) US3619866A (cs)
AT (1) AT285838B (cs)
CA (1) CA924865A (cs)
CH (1) CH470219A (cs)
CS (1) CS150202B2 (cs)
DE (2) DE1301439B (cs)
GB (1) GB1196757A (cs)
NL (1) NL156074B (cs)
SE (1) SE343492B (cs)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4056800A (en) * 1975-12-11 1977-11-01 Raytheon Company Magnetic field aligning means
US4222429A (en) * 1979-06-05 1980-09-16 Foundry Management, Inc. Foundry process including heat treating of produced castings in formation sand
US4249889A (en) * 1979-06-05 1981-02-10 Kemp Willard E Method and apparatus for preheating, positioning and holding objects
US4560521A (en) * 1984-03-28 1985-12-24 Northern Telecom Limited Maintaining homogeneity in a mixture
US4767584A (en) * 1985-04-03 1988-08-30 Massachusetts Institute Of Technology Process of and apparatus for producing design patterns in materials
US4935083A (en) * 1988-09-21 1990-06-19 Massachusetts Inst Technology Process for producing design patterns on materials
US5097888A (en) * 1990-09-17 1992-03-24 Augustine Iii Robert B Casting flow control system
US5545368A (en) * 1995-01-20 1996-08-13 Ford Motor Company Method of magnetically reinforcing composite components
US5865236A (en) * 1994-10-13 1999-02-02 Georg Fischer Disa A/S Crushed and graded magnetite ore for manufacturing moulds and cores
US20120042993A1 (en) * 2010-08-23 2012-02-23 Babcock & Wilcox Technical Services Y-12, Llc Control of Microstructure in Soldered, Brazed, Welded, Plated, Cast or Vapor Deposited Manufactured Components
WO2016023755A1 (de) * 2014-08-15 2016-02-18 Elkamet Kunststofftechnik Gmbh Kunststoffformteil und verfahren zu seiner herstellung
US10953590B2 (en) * 2016-01-25 2021-03-23 The Boeing Company Electromagnetic support tooling for composite part curing

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2455491A1 (fr) * 1979-05-02 1980-11-28 Pont A Mousson Procede et installation de moulage sous basse pression de pieces metalliques en empreinte en sable a paroi mince
DE19649014A1 (de) * 1996-11-27 1998-05-28 Ks Aluminium Technologie Ag Verfahren und Vorrichtung zum Herstellen von Gußstücken
DE102016214170A1 (de) * 2016-08-01 2018-02-01 MTU Aero Engines AG Induktionsheizvorrichtung, Vorrichtung mit mindestens einer Induktionsheizvorrichtung und Verfahren zur induktiven Erwärmung von Bauelementen oder eines Bauteilwerkstoffs

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3216074A (en) * 1964-02-26 1965-11-09 Edward N Harrison Method for making shaped foundry articles

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4056800A (en) * 1975-12-11 1977-11-01 Raytheon Company Magnetic field aligning means
US4222429A (en) * 1979-06-05 1980-09-16 Foundry Management, Inc. Foundry process including heat treating of produced castings in formation sand
US4249889A (en) * 1979-06-05 1981-02-10 Kemp Willard E Method and apparatus for preheating, positioning and holding objects
US4560521A (en) * 1984-03-28 1985-12-24 Northern Telecom Limited Maintaining homogeneity in a mixture
US4767584A (en) * 1985-04-03 1988-08-30 Massachusetts Institute Of Technology Process of and apparatus for producing design patterns in materials
US4935083A (en) * 1988-09-21 1990-06-19 Massachusetts Inst Technology Process for producing design patterns on materials
US5097888A (en) * 1990-09-17 1992-03-24 Augustine Iii Robert B Casting flow control system
US5865236A (en) * 1994-10-13 1999-02-02 Georg Fischer Disa A/S Crushed and graded magnetite ore for manufacturing moulds and cores
US5545368A (en) * 1995-01-20 1996-08-13 Ford Motor Company Method of magnetically reinforcing composite components
US20120042993A1 (en) * 2010-08-23 2012-02-23 Babcock & Wilcox Technical Services Y-12, Llc Control of Microstructure in Soldered, Brazed, Welded, Plated, Cast or Vapor Deposited Manufactured Components
US9181611B2 (en) * 2010-08-23 2015-11-10 Consolidated Nuclear Security, LLC Control of microstructure in soldered, brazed, welded, plated, cast or vapor deposited manufactured components
WO2016023755A1 (de) * 2014-08-15 2016-02-18 Elkamet Kunststofftechnik Gmbh Kunststoffformteil und verfahren zu seiner herstellung
US10751919B2 (en) 2014-08-15 2020-08-25 Elkamet Kunststofftechnik Gmbh Plastic molded part and method for producing the same
US10953590B2 (en) * 2016-01-25 2021-03-23 The Boeing Company Electromagnetic support tooling for composite part curing

Also Published As

Publication number Publication date
AT285838B (de) 1970-11-10
DE1558123B2 (de) 1976-02-05
SE343492B (cs) 1972-03-13
NL156074B (nl) 1978-03-15
DE1558154B2 (de) 1975-01-02
CA924865A (en) 1973-04-24
CH470219A (de) 1969-03-31
CS150202B2 (cs) 1973-09-04
DE1301439B (de) 1969-08-21
GB1196757A (en) 1970-07-01
NL6714618A (cs) 1968-05-13
DE1558154A1 (de) 1970-03-19
DE1558123A1 (de) 1970-03-19

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