US3314116A - Gasifiable casting pattern - Google Patents

Gasifiable casting pattern Download PDF

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US3314116A
US3314116A US298676A US29867663A US3314116A US 3314116 A US3314116 A US 3314116A US 298676 A US298676 A US 298676A US 29867663 A US29867663 A US 29867663A US 3314116 A US3314116 A US 3314116A
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Prior art keywords
casting
pattern
gasifiable
layer
feeder head
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US298676A
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Wittmoser Adalbert
Schade Johannes
Krzyzanowski Erich
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Full Mold Process Inc
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Full Mold Process Inc
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D15/00—Casting using a mould or core of which a part significant to the process is of high thermal conductivity, e.g. chill casting; Moulds or accessories specially adapted therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C3/00—Selection of compositions for coating the surfaces of moulds, cores, or patterns
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C7/00—Patterns; Manufacture thereof so far as not provided for in other classes
    • B22C7/02—Lost patterns
    • B22C7/023—Patterns made from expanded plastic materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/02—Sand moulds or like moulds for shaped castings
    • B22C9/04—Use of lost patterns
    • B22C9/046—Use of patterns which are eliminated by the liquid metal in the mould
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D27/00—Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting
    • B22D27/20—Measures not previously mentioned for influencing the grain structure or texture; Selection of compositions therefor

Definitions

  • the present invention relates to a casting arrangement
  • the present invention is concerned with improvements relating to gasifiable patterns.
  • lost patterns can be applied that means patterns which are destroyed after embedding, for example when employing a wax pattern which is melted out.
  • the present invention contemplates in a casting arrangement, in combination, a molding material having embedded therein a body consisting essentially of a gasifiable member having substantially the configuration of an article to be cast and adapted to be gasified at an elevated temperature corresponding to the temperature of "a molten casting charge adapted to be cast to form the article, and a layer consisting of a solid material which remains solid at the elevated temperature, contacting and substantially completely covering the outer surface of the gasifiable member.
  • the present invention contemplates for use in a casting arrangement, a casting pattern, comprising, in combination, a gasifiable body having substantially the configuration of an article to be cast and being adapted to be gasified at an elevated temperature corresponding to the temperature of a molten casting charge adapted to be cast to form the article the gasifiable body having distributed therethrough a substance adapted to act on the molten casting charge, and a layer consisting of a solid material which remains solid and is gas permeable at the elevated temperature, contacting and substantially completely covering the outer surface of the gasifiable body and having incorporated therein a substance adapted upon contact with the casting charge to affect the surface properties of the cast article.
  • the present invention also includes a method of casting, comprising the steps of embedding in a mold body a form which is gasifiable substantially without residue on subjection to a molten casting charge and which is shaped for exact reproduction as a casting and the surface of which is covered with a layer consisting of a solid material which remains solid and is gas permeable at the temperature of the molten casting charge, providing in the mold body and in the layer a passage for a molten casting charge to the embedded form, and pouring into the passage a molten casting charge for gasifying and replacing the embedded form in the mold body.
  • the present invention is also concerned with patterns which consist essentially of combustible or gasifiable substances such as expanded plastics and the like, which patterns are particularly suitable as feeder heads of the type which are frequently incorporated in casting arrangements in order to prevent formation of shrinkage cavities during casting of the molten metal.
  • the feeder head patterns according to the present invention have been found to give very good results in connection with the process of casting which is described in US. Patent No. 2,830,343.
  • the present invention also contemplates in a casting arrangement, in combination, a casting pattern consisting'essentially of a gasifiable member having substantially the configuration of an article to be cast and consisting essentially of a material adapted to be gasified at an elevated temperature corresponding to the temperature of a molten casting charge adapted to be cast to form the article, a feeder head pattern of substantially spherical configuration and consisting essentially of a material adapted to be gasified at the elevated temperature operatively connected to the casting pattern, and a body of molding material enveloping and having embedded therein the casting pattern and the substantially spherical gasifiable feeder head.
  • the present invention utilizes a gasifiable casting pattern of expanding plastic, for instance of polystyrene or polyethylene and is concerned with an improvement of the casting method which is disclosed in US. Patent No. 2,830,343, according to which the gasifiable casting pattern is embedded in a molding material, for instance, a molding sand or other loose, non-shaping material to which a cold setting binder may be added, and whereby the pattern is gasified and decomposed by the heat of the penetrating melt or molten casting charge.
  • a gasifiable casting pattern of expanding plastic for instance of polystyrene or polyethylene and is concerned with an improvement of the casting method which is disclosed in US. Patent No. 2,830,343, according to which the gasifiable casting pattern is embedded in a molding material, for instance, a molding sand or other loose, non-shaping material to which a cold setting binder may be added, and whereby the pattern is gasified and decomposed by the heat of the penetrating melt or
  • the outer surface of the pattern is provided with a shell-like, substantially incombustible coat or layer which will not be affected by the temperature of the penetrating melt and which preferably will be highly permeable to gas or becoming permeable to gas during the pouring process. It is also within the scope of the present invention to incorporate in the cellular plastic casting pattern solid or gaseous materials which will act on, or react with, the molten casting charge, for instance in the case of a molten metal casting charge, a material which will cause a metallurgical treatment of the casting metal.
  • the present invention thus overcomes the difficulties experienced up to now in connection with gasifiable casting patterns and will result in the production of cast bodies or castings of the desired surface structure, even when embedded in a loose molding material such as dry quartz sand which need not contain any binder. Even metal shot or similar materials may be used as the molding material. Furthermore, according to the present invention, not only an improvement of the surface of the casting is achieved but also of its inner structure which may be influenced by the incorporation of suitable materials in the gasifiable cellular plastic casting pattern.
  • the shell-like, substantially incombustible coat or layer on the outer face of the cellular plastic pattern will also advantageously act as a barrier preventing the escape of alloying and similar materials which may have been incorporated in the cellular gasifiable plastic casting pattern.
  • the surrounding in'combustible layer may be such as to prevent passage therethrough of alloying or other materials which had been distributed throughout the gasifiable plastic pattern.
  • the porous layer thus may be traversed by the gases formed, for instance, by pyrolysis of the cellular plastic but will retain and prevent passage therethrough of the particles of the alloying or the like material in the mold, which particles of alloying or the like material will thus be incorporated in, or react with, the casting charge.
  • FIG. 1 is a perspective view of a gasifiable casting pattern according to the present invention
  • FIG. 2 is a cross sectional view taken along lines II-II of FIG. 1;
  • FIG. 3 is an elevational view partially in cross section of a casting pattern for a radiator, according to the present invention.
  • FIG. 4 is a cross sectional view taken along lines -IV-IV of FIG. 3;
  • FIG. 5 is an elevational cross sectional view of a casting mold incorporating the casting pattern of FIGS. 1 and 2;
  • FIGS. 6-10 will serve primarily to illustrate embodiments of the present invention which encompass a gasifiable feeder head
  • FIG. 6 is an elevational view in cross section of a molding box with embedded feeder head and casting pattern
  • FIG. 7 is a cross sectional view taken along line A-A of FIG. 6;
  • FIG. 8 is an elevational, cross sectional view of another embodiment of the present invention.
  • FIG. 9 is a fragmentary, elevational, cross sectional view of a further embodiment of the present invention.
  • FIG. 10 is a fragmentary, elevational, cross sectional view of yet another embodiment of the present invention.
  • the casting pattern 1 which is illustrated in FIGS. 1, 2 and 5 may serve as an example for producing a casting in accordance with the present invention without requiring a core, while at the same time providing the casting with hardened surface portions in the area of the wheel body. Furthermore, as illustrated in FIG. 5, the casting will be produced in accordance with the present invention so as to be substantially free of cavities and pipings.
  • Tthe upwardly extending portions 2, as shown in FIG. 1, serve for reliable attachment of the risers and feeding conduits shown in FIG. 5.
  • the gasifiable foamed plastic pattern 1 carries a porous layer or coat 3 which covers the entire outer surface of plastic pattern 1.
  • Incorporated and substantially evenly distributed throughout foam cellular plastic pattern 1 may be alloying materials or other materials which will act on the molten casting charge when the same is introduced into the mold so as to gasify and replace the plastic pattern.
  • Interposed between the layer 3 of solid material, which remains solid at the temperature of the molten casting charge and which preferably will be gas permeable at such temperature, and the gasifia'ble member 1 may be a layer 4 of a material adapted to act on and to influence the surface portion of the casting during formation of the same, for instance to increase the hardness of the surface portion.
  • FIGS. 3 and 4 illustrate one of the relatively rare cases when by proceeding in accordance with the present invention it is nevertheless desirable to use a core.
  • the outermost layer 31 as shown in FIGS. 3 and 4 consists of a solid material which will remain solid at casting temperatures and layer 31 contacts the outer surface of the gasifiable cellular plastic pattern 32.
  • the core consists of a cellular plastic body 33 and a layer 34 interposed between cellular plastic core 33 and cellular plastic pattern 32.
  • Layer 34 consists of a material of low heat conductivity so that upon introduction of the molten casting charge and replacement of gasifiable plastic pattern 32 by the casting charge, heat penetration toward the gasifiable cellular plastic core portions 33 will be considerably retarded, namely for a sutficient length of time so that gasification of plastic core bodies 33 will take place only after the portion of the casting charge adjacent to layer 34'l1as been solidified and has become shape-retaining and self-supporting.
  • cores containing a gasifiable body are particularly suitable for castings which include relatively thin walls and which are formed with one or more inner cavities access to which is relatively difiicult.
  • FIG. 5 illustrates the casting pattern of FIGS. 1 and 2 incorporated in a molding arrangement which includes a shell 51, mold body 52, open feeder funnel 53 and feeder 54 with riser 55.
  • Feeding funnel 53, feeder 54 and riser 55 consist, initially similarly to pattern 1, of gasifiable cellular plastic material and feeding funnel 53 and feeder 54 are surrounded by a layer of heat insulating material 56.
  • the foamed cellular gasifiable plastic pattern again may have incorporated therein suitable alloying or treating materials for acting on or reacting with the casting charge.
  • Heat insulating layers 56 may consist of the porous gas permeable solid material which remains solid at casting temperatures as described further above.
  • the spherical blind riser 57 which is also surrounded by heat insulating layer 56 is formed with a small cutout at its upper portion which will serve for maintaining the elevated temperature of the melt for somewhat longer period of time.
  • the constriction underneath spherical riser 57 will facilitate breaking off the material which has solidified in riser 57.
  • Feeder and riser arrangements which are surrounded by heating means, usually providing heat by an alumin'o-thermic or the like process, or by insulating materials have been known for a long time.
  • heating means usually providing heat by an alumin'o-thermic or the like process, or by insulating materials
  • insulating materials have been known for a long time.
  • these elements had to consist of pressure resistant, hard, ceramic hollow bodies which had a relatively limited heating or insulating effect and were quite expensively, while, according to the present invention, these members will consist of a form of gasifiable cellular plastic material which is covered with a layer of suitable insulating material or the like.
  • the materials which may be used for forming the solid gas permeable layer 3 and which also may be used [for forming the heat insulating layer 56, are conventional materials which are, per se, known in the art.
  • Heat resistant materials which are porous or which will become highly permeable to gas when exposed to the temperature of the molten casting charge are highly suitable for the first purpose. These materials include diatomaceous earth or kieselguhr, asbestos, synthetic mineral fibers such as mineral wool, fire clay, clay, pumice, bentonite, perlite, vermiculite and the like, to which quartz sand or a similar material may be added if desired.
  • binding agents for these mineral materials may be used thermosetting or preferably cold setting substances such as plaster of Paris, cement, starch or synthetic resins, the latter being preferred.
  • the layer is formed by preparing a suspension of the mineral material and binding agent in water, to which suspension a suitable wetting agent and/or film forming agent may be added and which is then applied to the cellular plastic pattern, for instance, by hand, spray gun, immersion or other methods.
  • the coating or layer will require only a short period of air drying, but it need not be subjected to a special drying process and may be allowed to stand in wet condition.
  • the thickness of the coating preferably will not exceed 6 mm. and more preferably will be between 2 and 5 mm. The outside of the layer or coating may remain in rough and uneven condition.
  • such treating layer or coating may consist of graphite, tellurium or ferrosilicon, in other cases, particularly when producing light metal castings, a treating layer of silicon or sulfur frequently will be found advantageous for improvement of the surface quality of the casting.
  • the specific material of which the heat resistant gas permeable layer is to be formed will depend on the type of casting which is to be produced, such as whether an aluminum casting is to be produced at about 700 C. or a steel casting at about 1,500 C.
  • the heat resistant porous layer may be formed of a mixture of about 85% by weight of unblown perlite, about 5% of water glass (aqueous solution containing 30% by weight of sodium silicate) as binder and about 10% by weight of ground graphite.
  • Water which may contain a wetting agent and a filmforming agent is added in an amount sufficient to form a stiif paste which may be easily applied to the cellular casting pattern by hand and which dries quickly and adheres well to the surface of the cellular plastic pattern.
  • a greater quantity of water is added so as to achieve the desired consistency which is best suitable for the respective manner of applying the paste.
  • the perlite in the above-described mixture may be replaced by similar proportions of mineral wool, kieselguhr, ground pumice and the like.
  • the water glass binder may be replaced by a starch solution or a suitable solution or dispersion of synthetic resin.
  • the graphite may be suitably replaced by ferro-silicon or silicon.
  • the materials which may be incorporated in the heat resistant layer or which may be interposed between the heat resistant layer and the surface of the cellular plastic pattern, may either be mixed into the mass of which the heat resistant layer is formed, or may be applied as an intermediate coating, for instance dispersed in alcohol or water containing a wetting agent and/or film forming agent.
  • the material which is intended to have a metallurgic effect on the melt or casting charge, or to alloy with the same, may be distributed as evenly as possible in the plastic material prior to blowing of the same, so that as a result of the expansion of the plastic material, an even distribution of the added materials will be accomplished in the cellular gasifiable plastic pattern.
  • the gasifiable expanded plastic material which contains the evenly distributed additional material may also be used to form the pouring system of the mold.
  • materials such as ferrosilicon or nodular graphite-forming elements such as magnesium and corium may be added.
  • Powdery substances may also be added to the expanded plastic for either preventing or promoting the solidification of cast-iron alloys in the form of white cast iron, for example magnesium and silicon (preventives) or sulfur and tellurium (promoters).
  • alloying constituents such as vanadium, molybdenum and the like may be introduced into the melt in accordance with the present invention.
  • Such alloying materials or other materials which serve to influence the quality of the casting formed of the molten casting charge, are usually added. in such quantities that, with reference to the weight of the casting, the alloying metals are present in an amount of up to 1%, silicon in an amount of up to 0.8% and magnesium in an amount of up to 0. 1%.
  • the expanded plastic when employing the gasifiable expanded plastic pattern as carrier, may contain up to 500% of its weight of alloying metal or silicon, or up to about 50% of its weight of magnesium, based on the weight of the expanded plastic.
  • the additional material may be incorporated in the preexpanded granulate or in the monomers 01f the plastic.
  • the added material may be distributed homogeneously, prior to the polymerization, in one or more of the monomers prior to their admixture, or in the monomer mixture.
  • the added material should be introduced in finely sub-divided form. This last procedure is particularly advantageous because it will result in a very even distribution of the added material, for instance an alloying constituent, in the expanded plastic.
  • the expansion of the plastic polymer will be carried out with the help of a suitable expanding agent under the influence of the super-heated steam, then certain difiiculties are encountered when the added material, for example magnesium in powder form, is attacked by water. If, on the other hand, the added material is introduced into the monomeric resin, then the material which is sensitive to steam will be distributed very homogeneously in plastic expanded with the use of steam and apparently remains protected against attack by Water due to the plastic material surrounding each of the particles of magnesium or the like.
  • the thickness of the thus formed dry layer of low thermal conductivity preferably will be about 23 mm. and its weight about 300 grams per square meter.
  • the heat insulating layer 56 which primarily covers the cellular plastic material which is located in place of the riser and feeder conduits, preferably will consist of a material of the type which is suitable for forming layers 3 or 31, and very good results are achieved with respect to forming such porous layer by using therefor mineral wool and a smoothening and binding agent such as bentonite.
  • layers 56 preferably will be considerably thicker than layers such as layers 3 and 31.
  • the casting method of the present invention is not limited to any specific casting charge or material. It is possible to cast according to the present invention substantially all casting metals such as bronze, light metals, iron, steel, heavy metals, as well as glass and silicate melts (quartz), molten A1 SiC and the like. It is of course required that the melt will be sufficiently fluid within a temperature range which will be sufficiently above the decomposition or gasification temperature of the foam plastic pattern, and the last condition generally is met by a temperature of about 400 C. Furthermore, it is of course desirable that there should be as little reaction as possible between the molten charge and the porous heat resistant layer or the layer of low heat conductivity which covers the plastic pattern.
  • substantially all casting metals such as bronze, light metals, iron, steel, heavy metals, as well as glass and silicate melts (quartz), molten A1 SiC and the like. It is of course required that the melt will be sufficiently fluid within a temperature range which will be sufficiently above the decomposition or gasification temperature of the foam plastic pattern, and the last
  • the plastic pattern according to the present invention is also suitable for forming castings in a mold body consisting of loose sand without binder, for instance of free flowing quartz sand.
  • reactants such as alloying elements
  • a cast body of alloyed metal can be produced.
  • the loss of the usually valuable reactants or alloying materials is insignificant and can be further reduced by using the porous heat resistant layer interposed between the cellular plastic pattern and the mold body.
  • reactants are preferably applied as a thin layer or incorand similar materials which are known by the trade name Freon.
  • cores are not required in connection with patterns made of gasifiable expanded plastic material. If, however, in exceptional cases such cores are required due to poor accessibility of interior recesses of the plastic pattern, then the cores may be incorporated when foaming the expanded plastic patterns or they may be inserted thereafter.
  • cores made of conventional material, i.e., bonded sand and the like, but also cores which consist of gasifiable expanded plastic, provided that the gasifiable expanded plastic core is surrounded by a solid layer of low thermal conductivity, a so-called heat barrier layer, which will retard the transmission of heat from the melt to the expanded plastic core until after the melt layer adjacent the core, i.e., outwardly and adjacent of the solid layer of low heat conductivity, has solidified. Due to the high temperature of the casting charge, the core will then be gasified and a recess will remain in the casting, the latter being covered adjacent to such recess by the barrier layer which can be easily blown off or otherwise removed.
  • the barrier layer which can be easily blown off or otherwise removed.
  • Such barrier layer may consist of gypsum, clay, magnesium, calcium oxide or similar materials with hydraulic or organic binders such as polyvinyl acetate resin, starch and the like, or including metal powders or metal flakes, and the heat barrier layer may be applied to the expanding plastic core in the same manner as the heat resistant porous coating is applied to the expanded plastic pattern.
  • a thickness of the barrier layer of a few millimeters will be sutficient for retarding heat transmission therethrough to such an extent that the core will be gasified only after the portion of the charge adjacent to the barrier layer has solidified.
  • feeder is to be understood to denote additional storage space for the melt in the mold, i.e., additional space which can be filled with molten charge. Such an additional space is frequently desirable in order to prevent hole or piping formation in metals which have a great tendency to shrink.
  • Hitherto parts of the molding system being particularly susceptible to shrink hole formation were provided with heating means or heat insulating means by introducing suitable materials into the mold cavity after having removed a conventional pattern.
  • Thermite mixtures were used as heating means and hard burne-d ceramical materials which were brittle, rather expensive and of relatively limited effect served as insulating material.
  • the coating provided according to the invention represents a considerable progress in this respect, as it can be applied without difiiculty near or at all critical points of the pattern in any desired thickness in order to secure the insulating effect required in every particular case.
  • the thickness of the coating may amount to 20 mm. or more. If required, the insulating effect can be increased by conventional heating means.
  • the insulating portions of the coating may consist substantially of the above mentioned mineral fiber materials, i.e., asbestos or synthetic mineral fibers. Coatings of this kind have by far better insulating effects than the hollow ceramic bodies conventionally used for this purpose. In spite of the relatively loose structure of such fibrous materials no difficulties arise when embedding the pattern, as all forces or stresses occurring thereby are absorbed by the expanded plastic pattern.
  • the gasifiable patterns are not only suited for molding metals but also for molding other melts, as for example glass and silicate melts and the like provided that their casting temperature is sufficiently higher than the decomposition temperature of the expanded plastic material. 1
  • the solid content of the intermediate coatings 4 only comprise in percent of weight: 75-95 pulverized silica, 5-8 ground graphite, 1-5 water glass, up to 3 bentonite, and A1 0,, at the balance.
  • spherical feeder patterns are provided which consist of gasifiable material of the type described further above, for instance of a cellular plastic material which will be gasified at the temperature of the molten casting metal. It is essential, according to the present invention, that the feeder heads are of substantially spherical configuration and consist essentially of such gasifiable material. Thereby, the difiiculties and disadvantages are overcome which were encountered when it was attempted to provide spherical feeder heads by incorporating a hollow sphere in the molding material.
  • Feeder heads of spherical configuration are more suitable than feeder heads of other shapes because of the more favorable relationship between volume and surface of the feeder head.
  • a feeder head pattern which consists essentially of a gasifiable material, for instance of expanded plastics, and has a substantially spherical shape.
  • Such spherical feeder head pattern can be suitably arranged, for instance, in the down gate or runner itself and also directly adjacent to the casting pattern.
  • the spherical gasifiable feeder head pattern may be covered with an essentially incombustible heat-insulating layer.
  • This layer should be such as to resist erosion and should consist of a material which is either porous or which will become gas-permeable when exposed to the heat of the molten casting metal.
  • the heat insulating layer will consist of mineral fibers which are mixed with a hardenable binding agent, substantially as described further above with respect to the gasifiable bodies forming the casting pattern of the present invention.
  • the thickness of the heat insulating layer surrounding the gasifiable feeder head pattern preferably will be less than 3 mm.
  • the gasifiable feeder head patterns with a layer of an exothermic substance, in which case the layer may he of considerably greater thickness than 3 mm.
  • exothermic heating arrangements i.e., feeder and riser arrangements which are surrounded by heating means which provide heat, for instance by an alumino-thermic or the like process, are, per se, known to those skilled in the art, however, it is now proposed to utilize such alumino-thermic or the like heating processes or exothermic layers in combination with gasifiable casting patterns and spherical and gasifiable feeder heads.
  • alloying and/or other metallurgically effective substances either uniformly or non-uniformly in the feeder head pattern.
  • the substances intended for incorporation in the casting may be embedded in the feeder head pattern spaced from the 'center portion thereof or even in the: outer non-gasifiable layer which surrounds the feeder head. This is desirable because alloying substances or the like, if located in the center portion of the feeder head would be swept away instantaneously by and with the penetrating melt.
  • the process is more or less similar, provided however, that the alloy and/ or exothermic substances are, for instance, foamed into the top or outer layer of the feeder head pattern or, if they are embedded, are located in appropriately arranged cavities of the feeder head pattern, namely so that the alloying or other treating substances will not be instantaneously swept into the casting pattern by the first portion of molten metal entering the feeder head. It is possible by this method to achieve a controlled mixing of the molten casting metal with the alloying constituents. It may be mentioned here that the positioning and the amount of alloying or other substances which are to be incorporated in the feeder head pattern will of course vary depending on the size and shape of the casting which is to be produced.
  • the feeder head will be formed with a passage therethrough which substantially will be a continuation of the passage formed by the runner through which molten metal is introduced to the feeder head. Provision of such a passage is imp-ortant'in many cases in which it is desirable that as little as possible of the carbon formed upon gasification of the feeder head will enter into the casting pattern or mold cavity in which the cast body is to be formed.
  • the passage through the feeder head as described above, the: gasified plastic material of the feeder head or at least the major portion thereof will penetrate outwardly through the gas permeable layer surrounding the feeder head and thus will not be introduced into the mold cavity in which the cast body is to be formed.
  • the feeder head pattern of the present invention in combination with conventional casting arrangements and procedures using solid patterns for forming the casting cavity in the mold.
  • at least the patterns for the runner or downgate will be gasifiable.
  • the feeder head when using lateral runners extending more or less horizontally toward the casting pattern, the feeder head may be arranged at the point where the vertical downgate bends to form the lateral runner. In this manner, a more favorable space utilization within the mold arrangement is achieved. It is also possible and frequently advantageous to form the gasifiable feeder head and runner patterns integral with each other from one piece of expanded plastic material whereby, preferably, the runner should be shaped, in accordance with aerodynamic prin ciples, so as to prevent the aspiration of air by the stream of molten metal flowing towards the feeder head.
  • inlet and/or outlet passages or the patterns for such passages, i.e., either upstream or downstream of the spherical feeder head, a conventional strainer core. If the feeder head pattern is arranged within the downgate pattern, then such strainer core may be placed either upwardly or downwardly of the feeder head pattern.
  • the combination of runners and spherical feeder heads is particularly suitable for the casting of ingots, because it is possible in this case to save material by surrounding the gasifiable feeder head pattern with exothermic material.
  • molding box 71 is shown with mold 72 therein corresponding to the shape of the object to be cast.
  • Feeder head pattern 73 is connected with runner 74, as well as with casting pattern 72 and therethrough connects with riser 75.
  • Feeder head pattern 73, as Well as runner 74, casting pattern 72 and riser 75, are formed of gasifiable material, i.e., material Which will be gasified at the temperature of the molten metal poured into to the mold for forming the casting.
  • feeder head pattern 73 is of substantially spherical shape and may be arranged in downgate 74 directly adjacent to casting pattern 72.
  • the patterns 72, 74 and 75 need not necessarily consist of gasifiable material, but may also be formed of conventional material such as wood, in which case the patterns 72, 74 and 75 must be removed before casting.
  • feeder head pattern 3 consists of gasifiable material.
  • Feeder head pattern 73 may be covered by a heat-insulating layer 73a and/or by an exothermic substance.
  • a core 73b, permeable to gas, may extend into the interior of the feeder head pattern 73, in a manner known per se.
  • the connecting pattern 73c between feeder head 73 and casting pattern 72 is formed, preferably as illustrated in FIG. 7, namely by arranging the spherical feeder head 73 closely adjacent to casting pattern 72.
  • feeder head pattern 73 is located in the bend 73d formed at the lower end of downgate 74 and, in this manner, the supply conduit for the molten metal becomes shorted and a better space economy is obtained.
  • a concentric runner 74 is provided and the feeder head pattern may consist of one or more portions '73 and 73" which may be provided with relatively large concentric, eccentric or, as shown, decentric grooves 73e into which, for instance, alloying or other metallurgically effective substances may be introduced.
  • the lower part of the feeder head pattern may be provided with annular recesses 73a as shown in the drawing, which may receive and hold at least one aligned protrusion 73] of the upper portion 73 of the feeder head pattern. It is possible to incorporate alloying materials uniformly or non-uniformly into and throughout the body of the feeder head pattern, or to distribute these materials only about the surface of the feeder head pattern.
  • the feeder head pattern has a hollow core or at least one passage 73g extending throughout the feeder head in the direction of flow of the molten metal. It is sometimes also preferred to utilize feeder head patterns according to the present invention to form spherical blind riser patterns 75' which simultaneously serve as feeder heads.
  • the combined runner feeder head pattern 73 includes strainer core 76 which in the illustrated embodiment is located upstream of feeder head pattern 73. However, as discussed further above, strainer core 76 or the like may also be arranged downstream of feeder head pattern 73.
  • FIG. 10 The fragmentary view of FIG. 10 will serve to illustrate the advantageous arrangement of a spherical gasifiable feeder head according to the present invention in connection with an ingot casting arrangement.
  • the feeder or feeder heads 73 are at least partly surrounded with heat insulating or exothermic materials.
  • feeder head 73 or at least the portion thereof closest to the mold cavity 78 should be surrounded by insulating materials to retard cooling of the molten metal passing through these portions of the feeder head.
  • feeder head pattern 73 may be embedded in a separate mold head block 77, or in the upper portion of the proper ingot boxes.
  • the ingot is poured through feeder head 73 into the cavity 78 which is surrounded by molding material 79.
  • a layer of refractory material present in a significant amount up to a quarter inch applied to the outer surface of said member and dries to a solid condition, said layer being solid and gas permeable at the temperature of the molten casing charge and said member with said layer applied thereto being embedded in a molding material, whereby said member will be gasified upon subjection to the molten casting charge.
  • a layer of refractory material which is applied to the outer surface of said member and dries to a solid condition, said layer being solid and gas permeable at the temperature of the molten casting charge, and said member with said layer applied thereto being embedded in a molding material, whereby said member is gasified upon subjection to the molten casta member gasifiable substantially without residue upon 4.
  • said layer being solid and gas permeable at the elevated temperature of the molten casting charge whereby said member and layer can be wholly embedded in a molding material and the member replaced by the molten casting charge.
  • a casting pattern member gasifiable substantially without residue on subjection to a molten casting charge and having substantially the configuration of an article to be cast
  • a casting pattern member gasifiable substantially without residue on subjection to a molten casting charge and having substantially the configuration of an article to be cast, said member having distributed therethrough a material in significant amounts up to 500% by Weight of the pattern to produce a predetermined characteristic in said molten casting charge, and
  • a layer of refractory material which is applied to the outer surface of said member and dries to a solid condition and remains solid and gas permeable at the temperature of the molten casting charge.
  • a casting pattern For use in a casting arrangement.
  • a casting pattern comprising in combination,
  • a layer of refractory material which is applied to the outer surface of said member in a slurry form and dries to a solid condition, said layer having incorporated therein a substance in significant amounts up to 10% by weight of the refractory material to produce a predetermined characteristic in the surface properties of the cast article when contacted by the molten casting charge.
  • a casting pattern consisting essentially of a member gasifiable substantially without residue on subjection to a molten casting charge and having substantially the configuration of an article to be cast
  • a blind riser pattern of substantially spherical configuration consisting essentially of a material gasifiable substantially without residue on subjection to a molten casting charge and being operatively con nected to said casting pattern, said pattern having a conical indentation in its upper surface extending downwardly into said pattern,

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)
US298676A 1962-04-02 1963-07-30 Gasifiable casting pattern Expired - Lifetime US3314116A (en)

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US615866A US3498360A (en) 1963-07-30 1966-11-01 Method of casting in a mold which is coated during casting

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GB12542/62A GB945208A (en) 1962-04-02 1962-04-02 Process for the manufacture of castings employing gasifiable patterns

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US3314116A true US3314116A (en) 1967-04-18

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Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3339620A (en) * 1964-12-21 1967-09-05 Full Mold Process Inc Cavityless casting pattern and method of making same
US3373795A (en) * 1965-08-10 1968-03-19 Trw Inc Gating of unshrouded airfoils to permit directional solidification
US3434527A (en) * 1966-01-06 1969-03-25 Allis Chalmers Mfg Co Method for ultra-high purity precision casting
US3455373A (en) * 1966-01-06 1969-07-15 Allis Chalmers Mfg Co Apparatus for ultrahigh purity precision casting
US3467172A (en) * 1966-08-01 1969-09-16 American Colloid Co Exothermic metallurgical charges
US3635280A (en) * 1969-11-07 1972-01-18 John T Parsons Self-aligned multipart combustible casting pattern and method of making same
US3654987A (en) * 1966-11-01 1972-04-11 Full Mold Process Inc Gasifiable casting care
JPS5017928Y1 (en&quot) * 1970-08-25 1975-06-02
US3934639A (en) * 1973-05-09 1976-01-27 Foseco International Limited Method of marking an ingot
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
US4464231A (en) * 1980-10-22 1984-08-07 Dover Findings Inc. Process for fabricating miniature hollow gold spheres
US4482000A (en) * 1982-07-26 1984-11-13 General Motors Corporation Variable-permeability pattern coating for lost foam casting
US4651798A (en) * 1984-09-17 1987-03-24 Rikker Leslie D Molding medium, method for making same and evaporative pattern casting process
US4842037A (en) * 1987-06-10 1989-06-27 Foseco International Limited Metal casting patterns
US20040108091A1 (en) * 2001-04-05 2004-06-10 Keisuke Ban Casting method and casting apparatus
CN110978874A (zh) * 2019-12-31 2020-04-10 中国美术学院 一种金属工艺品表面加工金属图文的工艺
CN111992664A (zh) * 2020-08-29 2020-11-27 晋城市金工铸业有限公司 一种球墨铸铁表面铬系白口化耐磨铸造工艺

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US3616841A (en) * 1967-10-30 1971-11-02 Energy Research And Generation Method of making an inorganic reticulated foam structure
EP0195512B1 (en) * 1985-02-27 1990-10-24 Japan Styrene Paper Corporation Casting method
EP0280830A1 (en) * 1987-03-02 1988-09-07 Battelle Memorial Institute Method for producing metal or alloy casting, composites reinforced with fibrous or particulate materials
CN104128558B (zh) * 2014-08-19 2016-01-27 成都桐林铸造实业有限公司 一种解决渗漏和粘砂的铸造工艺

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US1927076A (en) * 1931-07-18 1933-09-19 Nat Radiator Corp Wooden casting pattern
US2070821A (en) * 1933-11-22 1937-02-16 Magnesium Castings And Product Casting of magnesium and its alloys
US2205327A (en) * 1939-06-29 1940-06-18 Williams John Means for casting metals
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US2295227A (en) * 1942-09-08 Means fob casting metals
US2569899A (en) * 1949-01-07 1951-10-02 Fairbanks Morse & Co Mold for casting crankshafts
US2583533A (en) * 1945-04-17 1952-01-29 Hiensch Johannes Nathanael Method of destroying patterns
US2756475A (en) * 1953-02-24 1956-07-31 Gen Motors Corp Investment mold and core assembly
US2830343A (en) * 1956-04-26 1958-04-15 Harold F Shroyer Cavityless casting mold and method of making same
US2886869A (en) * 1956-08-01 1959-05-19 John M Webb Graphite refractory molds and method of making same
US2923990A (en) * 1960-02-09 Casting mold for fusible pattern
US3019497A (en) * 1958-11-21 1962-02-06 Howe Sound Co Making fine grained castings
US3114948A (en) * 1960-08-19 1963-12-24 Atlantic Casting And Engineeri Investment casting apparatus and method
US3169288A (en) * 1961-12-15 1965-02-16 Dow Chemical Co Coatings for patterns employed in cavityless casting process

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2295227A (en) * 1942-09-08 Means fob casting metals
US2923990A (en) * 1960-02-09 Casting mold for fusible pattern
US1927076A (en) * 1931-07-18 1933-09-19 Nat Radiator Corp Wooden casting pattern
US2070821A (en) * 1933-11-22 1937-02-16 Magnesium Castings And Product Casting of magnesium and its alloys
US2205327A (en) * 1939-06-29 1940-06-18 Williams John Means for casting metals
US2259634A (en) * 1940-01-15 1941-10-21 Castings Patent Corp Means for forming castings
US2583533A (en) * 1945-04-17 1952-01-29 Hiensch Johannes Nathanael Method of destroying patterns
US2569899A (en) * 1949-01-07 1951-10-02 Fairbanks Morse & Co Mold for casting crankshafts
US2756475A (en) * 1953-02-24 1956-07-31 Gen Motors Corp Investment mold and core assembly
US2830343A (en) * 1956-04-26 1958-04-15 Harold F Shroyer Cavityless casting mold and method of making same
US2886869A (en) * 1956-08-01 1959-05-19 John M Webb Graphite refractory molds and method of making same
US3019497A (en) * 1958-11-21 1962-02-06 Howe Sound Co Making fine grained castings
US3114948A (en) * 1960-08-19 1963-12-24 Atlantic Casting And Engineeri Investment casting apparatus and method
US3169288A (en) * 1961-12-15 1965-02-16 Dow Chemical Co Coatings for patterns employed in cavityless casting process

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3339620A (en) * 1964-12-21 1967-09-05 Full Mold Process Inc Cavityless casting pattern and method of making same
US3373795A (en) * 1965-08-10 1968-03-19 Trw Inc Gating of unshrouded airfoils to permit directional solidification
US3434527A (en) * 1966-01-06 1969-03-25 Allis Chalmers Mfg Co Method for ultra-high purity precision casting
US3455373A (en) * 1966-01-06 1969-07-15 Allis Chalmers Mfg Co Apparatus for ultrahigh purity precision casting
US3467172A (en) * 1966-08-01 1969-09-16 American Colloid Co Exothermic metallurgical charges
US3654987A (en) * 1966-11-01 1972-04-11 Full Mold Process Inc Gasifiable casting care
US3635280A (en) * 1969-11-07 1972-01-18 John T Parsons Self-aligned multipart combustible casting pattern and method of making same
JPS5017928Y1 (en&quot) * 1970-08-25 1975-06-02
US3934639A (en) * 1973-05-09 1976-01-27 Foseco International Limited Method of marking an ingot
US4249889A (en) * 1979-06-05 1981-02-10 Kemp Willard E Method and apparatus for preheating, positioning and holding objects
US4222429A (en) * 1979-06-05 1980-09-16 Foundry Management, Inc. Foundry process including heat treating of produced castings in formation sand
US4464231A (en) * 1980-10-22 1984-08-07 Dover Findings Inc. Process for fabricating miniature hollow gold spheres
US4482000A (en) * 1982-07-26 1984-11-13 General Motors Corporation Variable-permeability pattern coating for lost foam casting
US4651798A (en) * 1984-09-17 1987-03-24 Rikker Leslie D Molding medium, method for making same and evaporative pattern casting process
US4842037A (en) * 1987-06-10 1989-06-27 Foseco International Limited Metal casting patterns
AU601287B2 (en) * 1987-06-10 1990-09-06 Foseco International Limited Metal casting patterns
US20040108091A1 (en) * 2001-04-05 2004-06-10 Keisuke Ban Casting method and casting apparatus
US6848496B2 (en) * 2001-04-05 2005-02-01 Nissin Kogyo Co., Ltd. Casting method and casting apparatus
CN110978874A (zh) * 2019-12-31 2020-04-10 中国美术学院 一种金属工艺品表面加工金属图文的工艺
CN111992664A (zh) * 2020-08-29 2020-11-27 晋城市金工铸业有限公司 一种球墨铸铁表面铬系白口化耐磨铸造工艺

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CH427156A (de) 1966-12-31
BE627229A (en&quot)
GB945208A (en) 1963-12-23

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