US2388299A - Method of fabricating molds - Google Patents
Method of fabricating molds Download PDFInfo
- Publication number
- US2388299A US2388299A US504063A US50406343A US2388299A US 2388299 A US2388299 A US 2388299A US 504063 A US504063 A US 504063A US 50406343 A US50406343 A US 50406343A US 2388299 A US2388299 A US 2388299A
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- United States
- Prior art keywords
- mold
- coating
- water
- pattern
- silicon
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- 238000004519 manufacturing process Methods 0.000 title description 8
- 239000000203 mixture Substances 0.000 description 28
- 239000000463 material Substances 0.000 description 25
- 239000011248 coating agent Substances 0.000 description 22
- 238000000576 coating method Methods 0.000 description 22
- 229910052710 silicon Inorganic materials 0.000 description 20
- 239000010703 silicon Substances 0.000 description 20
- 229910052751 metal Inorganic materials 0.000 description 18
- 239000002184 metal Substances 0.000 description 18
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 10
- 239000011819 refractory material Substances 0.000 description 10
- 239000007788 liquid Substances 0.000 description 7
- 239000000243 solution Substances 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- -1 etc) Chemical group 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 5
- 150000002739 metals Chemical class 0.000 description 5
- 239000005871 repellent Substances 0.000 description 5
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 4
- 239000011230 binding agent Substances 0.000 description 4
- 238000005495 investment casting Methods 0.000 description 4
- 239000000377 silicon dioxide Substances 0.000 description 4
- 239000003981 vehicle Substances 0.000 description 4
- 239000003232 water-soluble binding agent Substances 0.000 description 4
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 238000005266 casting Methods 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 2
- 239000004115 Sodium Silicate Substances 0.000 description 2
- 229910052910 alkali metal silicate Inorganic materials 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 239000000460 chlorine Substances 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 238000007598 dipping method Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 235000013312 flour Nutrition 0.000 description 2
- 239000000499 gel Substances 0.000 description 2
- 125000005843 halogen group Chemical group 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 239000004576 sand Substances 0.000 description 2
- 229910052911 sodium silicate Inorganic materials 0.000 description 2
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 239000005955 Ferric phosphate Substances 0.000 description 1
- 229920000084 Gum arabic Polymers 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910018487 Ni—Cr Inorganic materials 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 239000004111 Potassium silicate Substances 0.000 description 1
- 241000978776 Senegalia senegal Species 0.000 description 1
- 229920002472 Starch Polymers 0.000 description 1
- 235000010489 acacia gum Nutrition 0.000 description 1
- 239000000205 acacia gum Substances 0.000 description 1
- 125000002877 alkyl aryl group Chemical group 0.000 description 1
- 125000000217 alkyl group Chemical group 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 125000003710 aryl alkyl group Chemical group 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 125000001797 benzyl group Chemical group [H]C1=C([H])C([H])=C(C([H])=C1[H])C([H])([H])* 0.000 description 1
- 125000000484 butyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- VNNRSPGTAMTISX-UHFFFAOYSA-N chromium nickel Chemical compound [Cr].[Ni] VNNRSPGTAMTISX-UHFFFAOYSA-N 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000006071 cream Substances 0.000 description 1
- 239000011928 denatured alcohol Substances 0.000 description 1
- GNEPOXWQWFSSOU-UHFFFAOYSA-N dichloro-methyl-phenylsilane Chemical class C[Si](Cl)(Cl)C1=CC=CC=C1 GNEPOXWQWFSSOU-UHFFFAOYSA-N 0.000 description 1
- LIKFHECYJZWXFJ-UHFFFAOYSA-N dimethyldichlorosilane Chemical compound C[Si](C)(Cl)Cl LIKFHECYJZWXFJ-UHFFFAOYSA-N 0.000 description 1
- 238000010410 dusting Methods 0.000 description 1
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 229940032958 ferric phosphate Drugs 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 150000004820 halides Chemical class 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- WBJZTOZJJYAKHQ-UHFFFAOYSA-K iron(3+) phosphate Chemical compound [Fe+3].[O-]P([O-])([O-])=O WBJZTOZJJYAKHQ-UHFFFAOYSA-K 0.000 description 1
- 229910000399 iron(III) phosphate Inorganic materials 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 239000005055 methyl trichlorosilane Substances 0.000 description 1
- JLUFWMXJHAVVNN-UHFFFAOYSA-N methyltrichlorosilane Chemical compound C[Si](Cl)(Cl)Cl JLUFWMXJHAVVNN-UHFFFAOYSA-N 0.000 description 1
- 239000002687 nonaqueous vehicle Substances 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 229910052913 potassium silicate Inorganic materials 0.000 description 1
- NNHHDJVEYQHLHG-UHFFFAOYSA-N potassium silicate Chemical compound [K+].[K+].[O-][Si]([O-])=O NNHHDJVEYQHLHG-UHFFFAOYSA-N 0.000 description 1
- 235000019353 potassium silicate Nutrition 0.000 description 1
- 230000002940 repellent Effects 0.000 description 1
- 239000011369 resultant mixture Substances 0.000 description 1
- 150000004760 silicates Chemical class 0.000 description 1
- 235000019795 sodium metasilicate Nutrition 0.000 description 1
- 235000019794 sodium silicate Nutrition 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 229910001256 stainless steel alloy Inorganic materials 0.000 description 1
- 235000019698 starch Nutrition 0.000 description 1
- 239000008107 starch Substances 0.000 description 1
- JIHHDUPGGJREGT-UHFFFAOYSA-N tetrachlorosilane;trichloro(methyl)silane Chemical compound C[Si](Cl)(Cl)Cl.Cl[Si](Cl)(Cl)Cl JIHHDUPGGJREGT-UHFFFAOYSA-N 0.000 description 1
- 125000003944 tolyl group Chemical group 0.000 description 1
- 239000000080 wetting agent Substances 0.000 description 1
- 229910052845 zircon Inorganic materials 0.000 description 1
- GFQYVLUOOAAOGM-UHFFFAOYSA-N zirconium(iv) silicate Chemical compound [Zr+4].[O-][Si]([O-])([O-])[O-] GFQYVLUOOAAOGM-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
- B22C1/16—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents
- B22C1/165—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents in the manufacture of multilayered shell moulds
Definitions
- the present invention relates to a method of fabricating molds for use in the precision casting of metal parts.
- a general type of mold for precision casting of metals comprises a lining of finely-divided refractory material adapted to present a smooth surface to the metal being cast and a strong, porous backing or investment material which constitutes the mold proper.
- Such molds are made by applying to the surface of a wax pattern a coating comprising essentially a finely-divided refractory material and a settable, water soluble binder.
- This fine-grained coating containing a water-soluble binder is adapted to form a smooth, continuous interface against which the metal solidifies. After the coating has hardened, the coated pattern is embedded in a hardenable, gelatinous investment material having the necessary strength, porosity, and other properties desired in a mold of this type.
- the wax When the wax is melted out of the unfired mold, it expands and has a tendency to crack the mold lining. If the lining cracks, small pieces of it break off and produce rough surfaces on the cast mold parts or even pits where such broken pieces are trapped in the cast parts. Also, when hot metal enters molds of complex design, the metal erodes the cracked coating even more and penetrates the cracks between the lining material and mold proper.
- the present invention is based on my discovery that the above-mentioned diificulties may be overcome and a strong, durable mold obtained by contacting the coating applied to the wax pattern with a composition comprising an organo-silicon halide.
- This treatment of the 1ming material renders the coating sufficiently water-repellent to prevent substantial solution thereof by the aqueous component of the investment material but does not apparently prevent a bonding of the investment material to the lining material sufllcient to prevent cracking and scaling of the lining during subsequent heating of the mold.
- the amount of carbon deposited by the treatment is so small that it does not affect the strength of the mold or cause any trouble due to evaporation or burning during the baking operation.
- a wax pattern which has preferably been washed with a suitable solvent, such as denatured alcohol, to remove any oily surface film, is provided with a surface coating of a finely-divided refractory material, such as silica or zirconia flour, which coating may conveniently be deposited by spraying, dipping, etc.
- a suitable solvent such as denatured alcohol
- Any suitable water-solubleinorganic binder may be used to bond the refractory material.
- the water-soluble silicates such as sodium silicate, sodium meta silicate, potassium silicate, and the like.
- the powdered refractory material is mixed with a solution of the silicate and the resultant mixture applied to the wax pattern.
- the mixture should be of the consistency of thick cream.
- the coating which may first be dusted with a refractory material having a particle size larger than the particle size of the refractory material in the coating, is allowed to dry. It is thereafter treated with a composition comprising an organo-silicon halide or mixture of organo-silicon halides adapted to render the surface of the lining material which will come in contact with the investment material sufliciently water-repellent to prevent solution thereof by the aqueous component of the investment material.
- any suitable organo-silicon halide or mixture may be employed in the practice of my invention and the treatment may be carried out with the organo-silicon halide in vapor, liquid, or solution form.
- the vapor treatment of water non-repellent materials with organo-siliconhalides to render them water-repellent is broadly disclosed and claimed in Patent 2,306,222 issued to Winton I. Patnode.
- Numerous examples of suitable organo-silicon halides are disclosed in the abovementioned Patnode patent including alkyl (e. g. methyl, ethyl, butyl, etc), aryl (e. g. phenyl), aralkyl (e. g. benzyl), alkaryl (e. g.
- Mixed organo-silicon halides such as methyl phenyl silicon chlorides may also be employed.
- the compositions employed in the practice of my invention may also contain silicon halides other than the organo-silicon halides.
- I may employ mixtures of organo-silicon halides and silicon tetrahalides, such for example as the methyl silicon chloride-silicon tetrachloride azeotropic mixtures disclosed and claimed in the copending application Serial No. 476,767, filed February 22, 1943, in the name of Frank J. Norton and assigned to the same assignee as the present invention.
- compositions containing a mixture of two or more organosilicon halides containing an average of more than one halogen atom per silicon are particularly useful for the practice of the present invention.
- the nec- 4.0 includes coating a fusible pattern with a refracessary water-repellency may be obtained, forexample, by dipping the coated pattern for a few seconds into either the liquid silicon halide or a solution thereof.
- the treated patterns are allowed to set or age in the open air at room or slightly elevated temperatures for a short period of time prior to investment thereof in the mold material proper.
- the hydrochloric acid which is a byproduct of the water-repellency treatment, is permitted to evaporate-so that it does not subsequently interfere with the gellation or setting of the mold material.
- the coated patterns then are invested in any suitable mold composition containing water as the liquid vehicle.
- These mold compositions contain essentially a coarsergrained refractory material, such as silica (sand), alumina, zirconia, zircon, and the like, and a water-soluble binder such as an alkali silicate,
- a particularly useful mold composition is one containing about 95 per cent sand and about 5 per cent ferric phosphate plus suflicient water which sets or gels within a a to form a mixture reasonable time. Such a mixture should remain fluid for a period of time sufficient to expel all of .the air entrapped during the pouring or packing of the mold material around the coated pattern.
- the mold and embedded pattern are allowed to stand for a number of hours, conveniently over night, to obtain a thorough setting of the gel bond. They are then heated slowly to about 110 C. to drive out volatile matter and melt the wax pattern. By carrying out this heat treatment with the mold in an inverted position, the
- fused wax of the pattern flows out of the mold, leaving a mold cavity.
- the mold is then further heated to temperature ranging, for example, between 1000 F. and 2000 F. preparatory to casting.
- This heating may have a threefold purpose, namely, to burn out all remaining wax and volatile matter; to expand the mold so as to compensate for metal shrinkage; and to produce a preheated mold that will enable thin sections to be filled before the metal freezes.
- the coating has been found to adhere most tenaciously to the investment proper.
- the 'fused metal or alloy desired to be cast may be introduced into the mold cavity, preferably under pressure, and after the cast metal has solidified, the mold is broken away and excess metal trimmed from the completed casting.
- the method of fabricating a mold which comprises coating a fusible pattern with a mixture of a finely-divided refractory material and an inorganic binding material, at least partially drying said coating, contacting said coating with a composition comprising an organo-silicon halide and thereafter embedding the coated pattern in a settable investment composition comprising arefractory material and an aqueous solution of a binder for said refractory material.
- the step which comprises contacting the coated pattern with an organo-silicon halide adapted to render the refractory coating waterrepellent before embedding the coated pattern in the investment material.
- the method of fabricating a mold for the precision casting of metals which comprises coating a fusible pattern with a mixture of silica flour and an aqueous solution of a water-soluble silicate, drying said coating, contacting said coating with a composition comprising a mixture of methyl silicon halides to render said coating water-repellent and thereafter embedding the coated pattern in a settable slip comprising a mixture of a comminuted refractory mold material and an aqueous solution of a water-soluble binder.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Molds, Cores, And Manufacturing Methods Thereof (AREA)
Description
Patented Nov. 6, 1945 2,388,299 METHOD OF FABBICATING MOLDS Rudolf H. Thielemann, Schenectady, N. aignor to General Electric Company,
tion of New York Y., aaa corpora- No Drawing. Application September 27, 1943, Serial No. 504,063
4 Claims. (Cl. 22-193) The present invention relates to a method of fabricating molds for use in the precision casting of metal parts.
A general type of mold for precision casting of metals comprises a lining of finely-divided refractory material adapted to present a smooth surface to the metal being cast and a strong, porous backing or investment material which constitutes the mold proper. Such molds are made by applying to the surface of a wax pattern a coating comprising essentially a finely-divided refractory material and a settable, water soluble binder. This fine-grained coating containing a water-soluble binder is adapted to form a smooth, continuous interface against which the metal solidifies. After the coating has hardened, the coated pattern is embedded in a hardenable, gelatinous investment material having the necessary strength, porosity, and other properties desired in a mold of this type.
Since the binder of the mold lining material which is applied to the wax pattern is watersoluble, it has been necessary in the past to employ with such linings investment materials containing a non-aqueous or substantially nonaqueous liquid vehicle, such as an alcohol, to prevent disintegration of the lining by the liquid component of the investment material. With the application of precision molds to the manufacture of larger, more complex-shaped parts, for example, parts containing thin, wide sections, from metals of relatively high melting points, such as stainless steel alloys of the nickel-chromium type, it has been found that-the usual investment materials containing non-aqueous vehicles are not sufilciently strong to back up or reinforce the precoat or lining material applied to the wax pattern. When the wax is melted out of the unfired mold, it expands and has a tendency to crack the mold lining. If the lining cracks, small pieces of it break off and produce rough surfaces on the cast mold parts or even pits where such broken pieces are trapped in the cast parts. Also, when hot metal enters molds of complex design, the metal erodes the cracked coating even more and penetrates the cracks between the lining material and mold proper.
Investment or mold materials containing water as the liquid vehicle offer the strength and density necessary to back up the lining coat of large complex-shaped molds and in these respects are much superior to investment materials containing non-aqueous binder vehicles. However, when a coated pattern is invested in such mold mixtures, the water tends to dissolve the water-soluble pattern coating and to wash it away so that a smooth surface free from imperfections is no longer presented to the metal being cast in such a mold.
The present invention is based on my discovery that the above-mentioned diificulties may be overcome and a strong, durable mold obtained by contacting the coating applied to the wax pattern with a composition comprising an organo-silicon halide. This treatment of the 1ming material renders the coating sufficiently water-repellent to prevent substantial solution thereof by the aqueous component of the investment material but does not apparently prevent a bonding of the investment material to the lining material sufllcient to prevent cracking and scaling of the lining during subsequent heating of the mold. The amount of carbon deposited by the treatment is so small that it does not affect the strength of the mold or cause any trouble due to evaporation or burning during the baking operation.
In the practice of my invention, a wax pattern which has preferably been washed with a suitable solvent, such as denatured alcohol, to remove any oily surface film, is provided with a surface coating of a finely-divided refractory material, such as silica or zirconia flour, which coating may conveniently be deposited by spraying, dipping, etc. Any suitable water-solubleinorganic binder may be used to bond the refractory material. I prefer to use the water-soluble silicates such as sodium silicate, sodium meta silicate, potassium silicate, and the like. The powdered refractory material is mixed with a solution of the silicate and the resultant mixture applied to the wax pattern. If desired, a small amount of any suitable commercial wetting agent and a small amount of starch, gum arabic, or the like, may be added to the mixture to improve its adhesion, cohesion and consistency. For best results the mixture should be of the consistency of thick cream. The coating, which may first be dusted with a refractory material having a particle size larger than the particle size of the refractory material in the coating, is allowed to dry. It is thereafter treated with a composition comprising an organo-silicon halide or mixture of organo-silicon halides adapted to render the surface of the lining material which will come in contact with the investment material sufliciently water-repellent to prevent solution thereof by the aqueous component of the investment material.
Any suitable organo-silicon halide or mixture may be employed in the practice of my invention and the treatment may be carried out with the organo-silicon halide in vapor, liquid, or solution form. The vapor treatment of water non-repellent materials with organo-siliconhalides to render them water-repellent is broadly disclosed and claimed in Patent 2,306,222 issued to Winton I. Patnode. Numerous examples of suitable organo-silicon halides are disclosed in the abovementioned Patnode patent including alkyl (e. g. methyl, ethyl, butyl, etc), aryl (e. g. phenyl), aralkyl (e. g. benzyl), alkaryl (e. g. tolyl) silicon halides and compounds containing hydrogen as well as one or more hydrocarbon radicals and halogen atoms attached to silicon. Mixed organo-silicon halides such as methyl phenyl silicon chlorides may also be employed. The compositions employed in the practice of my invention may also contain silicon halides other than the organo-silicon halides. For example, I may employ mixtures of organo-silicon halides and silicon tetrahalides, such for example as the methyl silicon chloride-silicon tetrachloride azeotropic mixtures disclosed and claimed in the copending application Serial No. 476,767, filed February 22, 1943, in the name of Frank J. Norton and assigned to the same assignee as the present invention. I prefer to use compositions containing a mixture of two or more organosilicon halides containing an average of more than one halogen atom per silicon. A mixture of dimethyl dichlorosilane and methyl trichlorosilane having a chlorine content of about 60 per cent is particularly useful for the practice of the present invention.
Ordinarily it is suflicient to contact the coated pattern with vapors of an organo-silicon halide composition for from 3 to 5 minutes. If a liquid organo-silicon halide composition or a solution of an organo-silicon halide is employed, the nec- 4.0 includes coating a fusible pattern with a refracessary water-repellency may be obtained, forexample, by dipping the coated pattern for a few seconds into either the liquid silicon halide or a solution thereof.
The treated patterns are allowed to set or age in the open air at room or slightly elevated temperatures for a short period of time prior to investment thereof in the mold material proper. In this way the hydrochloric acid, which is a byproduct of the water-repellency treatment, is permitted to evaporate-so that it does not subsequently interfere with the gellation or setting of the mold material. The coated patterns then are invested in any suitable mold composition containing water as the liquid vehicle. These mold compositions contain essentially a coarsergrained refractory material, such as silica (sand), alumina, zirconia, zircon, and the like, and a water-soluble binder such as an alkali silicate,
a water-soluble phosphate cement or the like. A particularly useful mold composition is one containing about 95 per cent sand and about 5 per cent ferric phosphate plus suflicient water which sets or gels within a a to form a mixture reasonable time. Such a mixture should remain fluid for a period of time sufficient to expel all of .the air entrapped during the pouring or packing of the mold material around the coated pattern.
The mold and embedded pattern are allowed to stand for a number of hours, conveniently over night, to obtain a thorough setting of the gel bond. They are then heated slowly to about 110 C. to drive out volatile matter and melt the wax pattern. By carrying out this heat treatment with the mold in an inverted position, the
fused wax of the pattern flows out of the mold, leaving a mold cavity. The mold is then further heated to temperature ranging, for example, between 1000 F. and 2000 F. preparatory to casting. This heating may have a threefold purpose, namely, to burn out all remaining wax and volatile matter; to expand the mold so as to compensate for metal shrinkage; and to produce a preheated mold that will enable thin sections to be filled before the metal freezes. During this heating cycle the coating has been found to adhere most tenaciously to the investment proper.
The 'fused metal or alloy desired to be cast may be introduced into the mold cavity, preferably under pressure, and after the cast metal has solidified, the mold is broken away and excess metal trimmed from the completed casting.
By means of my treatment of the mold lining, it has been possible to cast metal parts of intricate shapes from high melting point metals and alloys without experiencing any trouble due to solution of the mold lining during fabrication of the mold or cracking or breaking away of the mold lining during heat treatment of the mold or during casting of the metal part.
What I claim as new and desire to secure by Letters Patent of the United States is:
l. The method of fabricating a mold which comprises coating a fusible pattern with a mixture of a finely-divided refractory material and an inorganic binding material, at least partially drying said coating, contacting said coating with a composition comprising an organo-silicon halide and thereafter embedding the coated pattern in a settable investment composition comprising arefractory material and an aqueous solution of a binder for said refractory material.
2. In the method of fabricating a mold which tory composition adapted to form a smooth, ac-
terial, the step which comprises contacting the coated pattern with an organo-silicon halide adapted to render the refractory coating waterrepellent before embedding the coated pattern in the investment material.
3. The method of fabricating a mold for the precision casting of metals which comprises coating a fusible pattern with a mixture of silica flour and an aqueous solution of a water-soluble silicate, drying said coating, contacting said coating with a composition comprising a mixture of methyl silicon halides to render said coating water-repellent and thereafter embedding the coated pattern in a settable slip comprising a mixture of a comminuted refractory mold material and an aqueous solution of a water-soluble binder.
4. The method of fabricating a mold for the precision casting of metals which comprises applying to the surface of a fusible wax pattern a coating comprising finely-divided silica, water,
.and an alkali silicate, dusting the surface of the
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US504063A US2388299A (en) | 1943-09-27 | 1943-09-27 | Method of fabricating molds |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US504063A US2388299A (en) | 1943-09-27 | 1943-09-27 | Method of fabricating molds |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2388299A true US2388299A (en) | 1945-11-06 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US504063A Expired - Lifetime US2388299A (en) | 1943-09-27 | 1943-09-27 | Method of fabricating molds |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US2388299A (en) |
Cited By (28)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2430655A (en) * | 1945-04-10 | 1947-11-11 | Burgess P Wallace | Foundry facings and method of making same |
| US2441695A (en) * | 1944-05-31 | 1948-05-18 | Austenal Lab Inc | Casting mold |
| US2452416A (en) * | 1944-04-26 | 1948-10-26 | Gen Electric | Process of making dimethyl silicone products |
| US2463193A (en) * | 1946-09-26 | 1949-03-01 | Selas Corp Of America | Preparing investments for casting |
| US2491096A (en) * | 1945-08-31 | 1949-12-13 | Austenal Lab Inc | Casting mold |
| US2521839A (en) * | 1949-08-11 | 1950-09-12 | Austenal Lab Inc | Refractory casting mold and method of making same |
| US2522548A (en) * | 1946-10-03 | 1950-09-19 | Thoger G Jungersen | Method of making a phosphate gel and mold with phosphate gel binder |
| US2557971A (en) * | 1948-06-08 | 1951-06-26 | Jr Harold M Jacklin | Method of centrifugal casting |
| US2604398A (en) * | 1946-02-21 | 1952-07-22 | Eastman Kodak Co | Light-sensitive photographic stripping film |
| US2679669A (en) * | 1949-09-21 | 1954-06-01 | Thompson Prod Inc | Method of making hollow castings |
| US2703913A (en) * | 1950-02-06 | 1955-03-15 | Bristol Aeroplane Co Ltd | Precision casting |
| US2741817A (en) * | 1950-08-03 | 1956-04-17 | Universal Castings Corp | Heat disposable pattern for molding a blade cavity |
| US2744011A (en) * | 1950-04-11 | 1956-05-01 | Diffusion Alloys Ltd | Process for the manufacture of sintered articles |
| US2759232A (en) * | 1953-01-02 | 1956-08-21 | Arwood Prec Castings Corp | Process of removing wax, plastic, and like pattern materials from thin shell molds |
| US2763626A (en) * | 1951-06-21 | 1956-09-18 | Borden Co | Molding sand composition comprising a halogenated aliphatic hydrocarbon as a release agent |
| US2795022A (en) * | 1953-04-09 | 1957-06-11 | Shaw Process Dev Corp | Method of making moulds |
| US2811760A (en) * | 1953-04-01 | 1957-11-05 | Shaw Process Dev Corp | Method for the production of casting moulds |
| US2815552A (en) * | 1951-11-15 | 1957-12-10 | Vickers Electrical Co Ltd | Method of making a mold by the lost-wax process |
| US2836867A (en) * | 1950-12-04 | 1958-06-03 | Morris Bean & Company | Process of making mold |
| DE1035860B (en) * | 1951-08-30 | 1958-08-07 | Renault | Process for the production of a mold cover for precision casting by means of meltable models |
| US2875485A (en) * | 1953-12-17 | 1959-03-03 | Sulzer Ag | Precision casting mold and method of making the same |
| US2887557A (en) * | 1954-06-29 | 1959-05-19 | Stettner & Co Fabrik Elektro K | Silicones |
| DE1080738B (en) * | 1952-03-04 | 1960-04-28 | Boehler & Co Ag Geb | Multi-layered form for the precision or investment casting process |
| DE974520C (en) * | 1951-09-01 | 1961-01-26 | Renault | Precision casting process with lost wax |
| US2979790A (en) * | 1957-08-09 | 1961-04-18 | Shaw Process Dev Corp | Molds |
| DE1248237B (en) * | 1958-01-16 | 1967-08-24 | Dow Corning A G | Molding sand binders |
| US3718496A (en) * | 1970-11-16 | 1973-02-27 | Formica Corp | Textured caul plate surfaced with furnace cement |
| US3941864A (en) * | 1973-06-04 | 1976-03-02 | Wacker-Chemie Gmbh | Method for manufacturing molded structures and coatings based on inorganic binding agents |
-
1943
- 1943-09-27 US US504063A patent/US2388299A/en not_active Expired - Lifetime
Cited By (28)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2452416A (en) * | 1944-04-26 | 1948-10-26 | Gen Electric | Process of making dimethyl silicone products |
| US2441695A (en) * | 1944-05-31 | 1948-05-18 | Austenal Lab Inc | Casting mold |
| US2430655A (en) * | 1945-04-10 | 1947-11-11 | Burgess P Wallace | Foundry facings and method of making same |
| US2491096A (en) * | 1945-08-31 | 1949-12-13 | Austenal Lab Inc | Casting mold |
| US2604398A (en) * | 1946-02-21 | 1952-07-22 | Eastman Kodak Co | Light-sensitive photographic stripping film |
| US2463193A (en) * | 1946-09-26 | 1949-03-01 | Selas Corp Of America | Preparing investments for casting |
| US2522548A (en) * | 1946-10-03 | 1950-09-19 | Thoger G Jungersen | Method of making a phosphate gel and mold with phosphate gel binder |
| US2557971A (en) * | 1948-06-08 | 1951-06-26 | Jr Harold M Jacklin | Method of centrifugal casting |
| US2521839A (en) * | 1949-08-11 | 1950-09-12 | Austenal Lab Inc | Refractory casting mold and method of making same |
| US2679669A (en) * | 1949-09-21 | 1954-06-01 | Thompson Prod Inc | Method of making hollow castings |
| US2703913A (en) * | 1950-02-06 | 1955-03-15 | Bristol Aeroplane Co Ltd | Precision casting |
| US2744011A (en) * | 1950-04-11 | 1956-05-01 | Diffusion Alloys Ltd | Process for the manufacture of sintered articles |
| US2741817A (en) * | 1950-08-03 | 1956-04-17 | Universal Castings Corp | Heat disposable pattern for molding a blade cavity |
| US2836867A (en) * | 1950-12-04 | 1958-06-03 | Morris Bean & Company | Process of making mold |
| US2763626A (en) * | 1951-06-21 | 1956-09-18 | Borden Co | Molding sand composition comprising a halogenated aliphatic hydrocarbon as a release agent |
| DE1035860B (en) * | 1951-08-30 | 1958-08-07 | Renault | Process for the production of a mold cover for precision casting by means of meltable models |
| DE974520C (en) * | 1951-09-01 | 1961-01-26 | Renault | Precision casting process with lost wax |
| US2815552A (en) * | 1951-11-15 | 1957-12-10 | Vickers Electrical Co Ltd | Method of making a mold by the lost-wax process |
| DE1080738B (en) * | 1952-03-04 | 1960-04-28 | Boehler & Co Ag Geb | Multi-layered form for the precision or investment casting process |
| US2759232A (en) * | 1953-01-02 | 1956-08-21 | Arwood Prec Castings Corp | Process of removing wax, plastic, and like pattern materials from thin shell molds |
| US2811760A (en) * | 1953-04-01 | 1957-11-05 | Shaw Process Dev Corp | Method for the production of casting moulds |
| US2795022A (en) * | 1953-04-09 | 1957-06-11 | Shaw Process Dev Corp | Method of making moulds |
| US2875485A (en) * | 1953-12-17 | 1959-03-03 | Sulzer Ag | Precision casting mold and method of making the same |
| US2887557A (en) * | 1954-06-29 | 1959-05-19 | Stettner & Co Fabrik Elektro K | Silicones |
| US2979790A (en) * | 1957-08-09 | 1961-04-18 | Shaw Process Dev Corp | Molds |
| DE1248237B (en) * | 1958-01-16 | 1967-08-24 | Dow Corning A G | Molding sand binders |
| US3718496A (en) * | 1970-11-16 | 1973-02-27 | Formica Corp | Textured caul plate surfaced with furnace cement |
| US3941864A (en) * | 1973-06-04 | 1976-03-02 | Wacker-Chemie Gmbh | Method for manufacturing molded structures and coatings based on inorganic binding agents |
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