CA1051608A - Preparation of high temperature shell molds - Google Patents
Preparation of high temperature shell moldsInfo
- Publication number
- CA1051608A CA1051608A CA231,708A CA231708A CA1051608A CA 1051608 A CA1051608 A CA 1051608A CA 231708 A CA231708 A CA 231708A CA 1051608 A CA1051608 A CA 1051608A
- Authority
- CA
- Canada
- Prior art keywords
- composition
- binder
- alkyl
- carbon atoms
- silicate
- 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
Links
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
- B22C1/20—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 of organic agents
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/0008—Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
- C08K5/0016—Plasticisers
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/16—Nitrogen-containing compounds
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/16—Nitrogen-containing compounds
- C08K5/17—Amines; Quaternary ammonium compounds
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Mold Materials And Core Materials (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A binder composition and process for preparing shell molds are provided. The process comprises the first step of coating a pattern with a novel binder composition containing a silicate ester, preferably a prehydrolyzed alkyl orthosilicate ester in which the alkyl group has from 1 to 4 carbon atoms, an aminoalcohol, preferably one of the formula HORN(R')2 in which R is a divalent hydrocarbon radical having from 1 to .epsilon. carbon atoms, and R' is hydrogen, an alkyl radical or a radical of the formula -ROH, sufficient organic solvent to form a binder composition having an SiO2 content of from 10-35 percent by weight, and a refractory material; the second step of stuccoing and thereafter drying the coated pattern.
The coating, stuccoing and drying sequence is repeated until the desired coating thickness is achieved and then a sealing coat is applied, if desired.
A binder composition and process for preparing shell molds are provided. The process comprises the first step of coating a pattern with a novel binder composition containing a silicate ester, preferably a prehydrolyzed alkyl orthosilicate ester in which the alkyl group has from 1 to 4 carbon atoms, an aminoalcohol, preferably one of the formula HORN(R')2 in which R is a divalent hydrocarbon radical having from 1 to .epsilon. carbon atoms, and R' is hydrogen, an alkyl radical or a radical of the formula -ROH, sufficient organic solvent to form a binder composition having an SiO2 content of from 10-35 percent by weight, and a refractory material; the second step of stuccoing and thereafter drying the coated pattern.
The coating, stuccoing and drying sequence is repeated until the desired coating thickness is achieved and then a sealing coat is applied, if desired.
Description
1~5~
This invention relates to a binder composition for shell molds, and more particularly to a process for the preparation of shell molds for the casting of metals.
Precision casting of metal and other types of material in the molten state is used in many industries and, generally, such castings are made in expendable molds. There are three general types of processes for making the expendable molds and these may be classified as the "lost wax", the single investment and the double investment processes. These all have one thing in common; they are one-use molds in which the mold is generally destroyed in removing the casting therefrom. To provide an economical process, a master mold or pattern is initially prepared from which refractory molds are made by one of the above processes.
In the manufacture of precision castings by investment shell casting techniques, disposable patterns are made from waxes, plastic materials, frozen mercury -and other materials which readily may be removed from the mold. The investment cycle consists of m~king the pattern by injecting the pattern material into the die and gating the pattern to a central sprue to form a pattern cluster.
Generally, the pattern cluster is dipped into an agitated slurry of the coating composition, drained, stuccoed while still wet ~
with particulate mold material and aried. The dipping, draining, stucco- ;
ing and drying sequence is repeated he desired number of times, depen-ding on the thickness and strength of the shell mold desired.
Thereafter, the disposable pattern is removed by methods such as, for example, melting or solvent treatment and the mold cured by fir-ing at a temperature sufficient to remove the volatiles and provide adequate bonding. The molds are then heated and filled with molten metal and after cooling, the castings are removed from the sprue and finished in the usual manner.
The preparation of shell molds has been described in United States Patent No. 3,270,382 issued Septe~ber 6, 1966 to Emblem et al in which two different coatings are applied alternately - 1 -' ~ '~
,. . . . .
..
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;; ~
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to an expendable pattern. One coating consists of a gel-~orming acid hy-droly2ed alkyl silicate solution and the other coating consists of a gel-forming basic silicate ester. m e acid hydrolyzed solution and the basic silicate est~r o~ the applied coatings each act upon the other so as to cause gelation of the other.
In United States Patent No. 3,079,656 issued ~arch 5, 1963 to E~blem et al, the patentees describe the preparations of aminosilicates by an interchange reaction bet~^7een an alkyl silicate and an aminoalcohol, while removing the alcohol produced as the result of tne interchange reac-tion. The aminosilicates may be co~bined with a reEractory material and applied to an expendable pattern. The coating is gelled by the addition of water. Likewise, amLnoaIk~lsilicates have heen disclosed as binders in United States Patent ~o. 3,112,538 issued December 3, 1963 to Emblem et al.
The binder is combined with fine refractory powders to form a slurry which is ap~lied to a wax pattern. Each coating is allowed partially to harden before the next is applied. me coated pattern is then hardened for 24 hours before t~e wax pattern is removed. '~ -Binders containing a mixture of an alkyl silicate and an aminoalkyl silicate have been described in United S-tates Patent ~o. 3,329,520 issued July 4, 1967 to Emblem et al. These binders are combined wlth a refractory material and water and then cast into the desired s'nape.
A paint composition containing a mixture of organlc silicates and an amine having a pKa value above 7.8 is described in Australian Patent .~o. 163,467. However, wh~n the composition contains an amine such as, for . .
. .
" ' ~ ' ' . ' ' ~ ",, ' "`.'' '' ~, ' ' l~S~)8 example, monoethanolamine, the mixture must age for at least 48 hours and up to fourteen days before it can be used as a protective coating on said cores.
It is an object of one as~ect of this invention to provide a pro-cess for preparing shell molds.
An object of another aspect of this invention is to provide a pro-cess for preparing shell molds which utilize a single binder com~osition.
An object of another aspect of this invention is.to provide a pro-cess for preparing shell molds ~ich may be used after air drying for from 1 to 3 hours.
~ n object of a further aspect of this invention is to provide a binder composition which does not reouire the addition of additional water to cause gelation thereof.
An object of a still fur~her aspect of this invention is to provide a binder com~osition ~nich does not require removing the alcohol resul~ing from the esterification of an organosilicate and an aminoalcohol.
By one broad aspect, then, a coating composition is provided for the preparation of shell molds cc~prising a refractory material and a binder P
composition which is substantially free of water, the binder composition comprising a silicate ester, an ammoalcohol of the formula HOR~R')2 in which R is a divalent hydrocar~on radical having from 1 to 6 carbon atoms, Rl is selected from the group consisting of hydrogen, an alkyl radical of the formula -ROH in which R is the same as above, in which the mol ratio of anuno-alcohol to silicate ester is from 1:1 to 10:1, and an i.
'. ' . ' :, ~,, :
.
. .
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~ 15~6~
organic solvent, thereby to form a binder composition naving an SiO2 content of from 10 to 35 percent by weight based on the weiyht of the binder.
By a preferred variant, the silicate ester comprises a prehydro-lyzed alkyl orthosilicate in which alk;yl group has from 1 to 4 carbon atoms.
By oth~r variants, the prehydrolyzed alkyl orthosilicate is ethylpolysilicate or i5 silicate "40".
By yet oth~r variants, the aminoalcohol may ~e monoetnanolamlne or triet7nanola~ine.
By another variant, the composition may include, as additional additives, at least one of boron compounds and organic acids.
By one variant, t7ne boron compound is boric acid or an alhyl bor ate in which the alkyl ~roup contains 1 to 8 carbon aton~7.
By another variant, tne acid is a mo.~car~oxylic acid haviny from -1 to 10 carbon atoms.
By another aspeot of this invention, a process is provided for preparin~ a sllell mold which comprises: coating an expendable pattern with a oQmposition containing a binder which a,$ ~ubsta7ltially Eree of ~ater and refractory material, in which the ratio of refractory material to binder is from about 4 to 50 parts of refractory naterial per part of binder SiO2, the binder ccmprisi~g a silicate ester, an a7ninoalconol of t7ne formwla HO~N (R I ) 2 in which R is a dival~nt h ~ rbon radical having from 1 bD 6 carbon atQ~s~
R' is selected from the group oonæi~ting of hydrogen, an alkyl radical and a radical o the formula -R~H in which R is the s~mei as above, in ~ 4 ~-; j , ., - . , . . , , , ~, . . ................. .. .
: . . ~:, : ~,, , which the mol ratio of aminoalcohol to silicate ester is frorn 1:1 to 10:1 and sufficient organic solvent to provide an SiO2 content of from 10 to 35 percent by weight based on the weight of the binder; stuccoing the coated pa~tern, air drying; and repeating the above sequence of steps until a coat-ing of desired thickness is achieved.
By variants thereof, the si]icate ester may be a prehydrolyzed aIkyl orthosilicate in which the alkyl group has from 1 to 4 carbon atoms or the coating composition may also contain from 0.5 to 10 percent by ~7eight based on the ~leight of the binder cornposition of an alkyl borate.
By yet another aspect, the process includes the step of applying a seal coat, said seal coat comprising a composition containing a hydrolyzed silicate ester, a refractory material an~ an organic solvent.
m e process of an aspect of this inventlon constitutes an improve-ment in investment casting over that disclosed in the art. For e~ample, the binder oQmposition of an aspec~ of this invention does not require an aging period, i.e., the composition is ready to use substantially immediately after muxing the lngredients. rloreover, the resulting shell is ready for r use after air drying for from one to three .~ours. Also, the binder oom-position of an aspect of this invention gels in the presence of atmosp.~eric moisture and does not require adding additional water to the binder com~
position. In addition, the process of an aspect of this invention utilizes a single binder composition to prepare shell molds, whereas many of the shell molds prepared heretofore required at least two different types of binder compositions.
~ ~ 4 a - _ ~ `
'. :: :
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ccording to one varian-t and e~bodiment of this invention, previ-ously claimed and e~ched disposable patterns are coated with a binder com~
position containing a refractory material. s-tuccoing with a coarse refractory material and then dried to set the coating material. The sequence of steps is repeated until the desired eoating tnickness is achieved. The coated pattern thus formed may be sealed with a backup coating containing a hy-drolyzed silicate ester, a solvent and a refractory material, if desired.
The sllicate esters found to be useful in providing compositions r`
of aspects~f the present invention are tetraethyl orthosilicate, "condensed"
ethyl silicate and ethyl silicate "40". "Condensed" ethyl silicate is tetraethyl orthosilicate containing 10 percent polysilicates and is the un-distilled reaction product of silicon tetrachloride and 200-proof ethanol having a nominal composition of from 2 to 5 percent ethanol, 90 to 95 per-cent orthosilicate and from 5 to 10 percent polyethoxy polysilicates.
Ethyl silicate "40" is a mixture of polysilicates averaging 5 silicon atoms per m~lecule having a siliea content of 40 percent~ It is formed by reaet-ing silicon tetrachloride ~ith ethanol containing some water under conditions r such that a silica content of 40 percent is achieved. Other silicate esters which may be ~mployed are those that - 4 b -: - .'. , !, , ," ' ' , `' ~' ~ , ' ' ' ':,,, ' .:, ' . . , . : ' ~
~L~S.~ 8 are obtained from the hydrolysis and condensation of ethyl silicate "40".
Aminoalcohols which ma~ be employed in the binder composition of an aspect of this invention may be represented by the formula HORN(R')2 where R is a divalent hydrocarbon radical having from 1 to 6 carbon atoms, R' is hydrogen or an alkyl group having from 1 to 6 carbon atoms or a group of the formula -ROH in which R is the same as above.
Examples of suitable aminoalcohols are mono-, di-, or triethanolamine, monoisopropanolamine, 2-amino-butan-1-ol, 3-amino-propan-1-ol, 2-dimethyl-amino-2-methylpropan-1-ol and the like.
Any organic solvent which is a mutual solvent for the silicate ester and the aminoalcohol may be employed. It is preferred that the solvent have a boiling point below 250~C. and more preferably below 150C.
Examples of suitable organic solvents are aliphatic alcohols, such as, for example, methanol, ethanol, isopropanol, butanol; ketones, such as, for example, acetone, methyl ethyl ketone and aromatic hydroca~bons such as, for example, benzene, toluene and the like. Polyethers which may be employed as solvents in the binder composition of an aspect of this invention are glycol ethers such as, for example, monoalkylene glycol monoalkyl ethers, dialkylene glycol monoalkyl ethers 3 dialkylene glycol dialkyl ethers and monoalkylene glycol dialkyl ethers. Examples of preferred glycol ethers are ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol dibutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, and esters of the ethylene glycols such as, for example, ethylene glycol monobutyl ether acetate, ethylene glycol mono-methyl ether acetate and the like.
The amount of aminoalcohol employed in the binder composition of an aspect of this invention is not critical. It can be present in a mol ratio of aminoalcohol to ethyl silicate of from 1:1 to lO:l and more preferably from 3:1 to 8:1.
Generally the amount of silicate esters employed in the binder composition of an aspect of this invention is sufficient to provide a binder having an SiO2 content of the order from 10 to 35 percent and more preferably from 15 to 30 percent by weight bas d on the weight of the binder composition.
Refractory materials which may be employed in the binder com-position of an aspect of this invention are many and varied. Generally, well-known refractories such as, for example, the oxides and silicates -- -of silicon, alumina, zirconium, zinc, magnesium, chromium and titanium may be used. These include the acidic minerals, the neutral or amphot-10 eric minerals, especially those whose primary elements are found in Group II of the Periodic Table, the gel acid minerals, e.g., allophane and the basic minerals, e.g., zirkelite. Also, there should be mentioned the many synthetic materials including the zeolites, molecular sieves, ion-exchange resins and similar substances. Apart from the foregoing, zircon, grog, calcined clay, silica flour, sand anf fused silica may be used providing compositions of aspects of t~is invention. Examples of acidic, weakly acidic or neutral amphoteric minerals are fused silica, natural silica, zircon, stillimanite, zirconite, whicll is a mixture of silicates and oxides of zircon; mullite which is a high refractory 20 aluminum silicate, clays, magnesia9 and other metal oxides and silicates.
These refractory materials may be employed alone or in com-bination depending on the particular casting operation contemplated.
Also, the particle size of the refractory material is selected depending on the specific purpose for which the mold is being fabricated. In some cases, it is desirable to employ a mixture containing both relatively coarse and fine particles. G~nerally, a coarser refractory material is used in the stuccoing step than is used in the initial coating composi-tions, thereby providing a bond betweén one shell coat and the succes-sive coat.
A shell mold conforming to an aspect of this invention is pro-duced without the use of any other binder than the one described as an aspect of this invention. However, where a seal coat or backup coat is ' ' ' ': : , :
1~5160~
desired a bin~er composition containing a refractory material and sili-cate esters such as, for example, the prehydrolyzed type commercially available or those prepared by the acid hydrolysis of any of the commer-cially available forms of ethyl silicate, includinE monomeric orthosili-cate, "condensed" ethyl silicate or ethyl silicate "40" may be employed.
To prevent premature gelation of the seal coat composition, a small quantity of acid having an acidity greater than that of the hydrolyzed ethyl silicate or an acidic buffering agent can be added to the binder solution. The p~ oE the seal coat composition should be maintained in the range from 1 to 3.2. Suitable acids and buffering agents include hydrochloric acid, phosphoric acid, sulfuric acid, and ammonium nitrate. The quantity of acid or buffering agent employed will vary depending upon the acid or buffering agent used and the refractory aterial present in the composition.
The same refraGtory materials which were employed in the prior - coating composition may be used in the seal coat. Generally, these refractory materials are oxides and silicates of silicon, alumina, zirconium, zinc, tin, magnesium, chromium, titanium and the like. ~ther refractory materials such as, for example, grog, calcined clay, silica flour, sand or fused silica may also be used in the seal coat composi-tion.
These refractory materials may be employed ~everally or in any combination deemed desirable depending on the particular casting opera-tion contemplated.
The same solvents which were used in the initial coating com-position described above may be used in the seal coat. Examples of suitable solvents are the alcohols, ketones and polyethers such as, for example, the monoalkylene glycols monoalkyl ethers, dialkylene glycols monoalkyl ethers, monoalkylene glycols dialkyl ethers and dialkylene glycols dialkyl ethers.
The amount of binder employed in the coating composition is substantially determined by the particle size of the refractory materials . . .
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since the finer the refractory material the more readily it absorbs the binder 9 hence the more binder required. In some cases where the refractory particles are coarse, the amount of binder required may be such that for every 100 parts refract:ory material there may be used only that amount of binder necessary to provide 1 part of binder SiO2. Con-versely, where the particles of refractory material are extremely fine it may be necessary to use with each 4 parts of refractory material that amount of binder necessary to provide 1 part of binder SiO2. In other words, the ratio of refractory material to binder may range from 4 to 100 parts refractory material per part of binder SiO2.
In general, the seal coat composition is applied to the pre-viously dried coating and then dried in the presence of atmospheric moisture. In the event it is desired to accelerate the gelling of the seal coat,` then a basic material su~h as, for example, ammonia or ~ -organic amines such as, for example, aliphatic, aromatic and cyclic amines having up to 10 carbon atoms may be employed. Examples of suit-able amlnes are methylamine, mono-, di- and triethylamines, propylamine, n-butylamine, cyclohexylamine, hydrazine, piperidine, and the like.
After the pattern has been covered with the desired number of coats, it is dried at a temperature which may vary from 25C. up to the fluidizing temperature of the disposable pattern. The temperature may then be increased in a nonoxidizing atmosphere to fluidize and remove the disposable pattern therefrom. The resulting shell mold is subse-quently fired by exposure to a temperature of from 500 to 3000~C. in an oxidizing atmosphere for from 1 to 12 hours.
Various aspects of the invention are illustrated by the follow-ing examples in which all parts are by weight unless otherwise specified.
A wax tree pattern is sprued and gated to conform to the requirements of the metal cast and casting desired. The tree is momen-tarily etched in a 75 percent trichloroethylene - 25 percent isopropyl alcohol mixture and the excess removed with isopropyl alcohol. The .
p~ttern is allowed to dry before dipping into a coating composition prepared in the following manner:
Binder Composition Ingredients Parts Ethyl silicate (condensed) ~ 416 Ethanol 540 Ethanolamine 244 The binder composition is prepared by adding with agitation ethanolamine to a solution containing "condensed" ethyl qilicate and ethanol at a temperature of from 40 to 45C. The solution i8 stirred for one hour at this temperature, cooled to 30C. and filtered.
Approximately 300 parts of the binder composition prepared above is mixed with 200 parts of ziroon (325 mesh) and 400 parts of fused silica (available from Ransom and Randolph Company and identified by the Trade Mark Rancosil #l) to form a slurry. The wax pattern is coated with the slurry, stuccoed with a fused silica sand (available from Ransom & Randolph Co~pany and identified by the Trade Mark Rancosil A) and air dried for 15 minutes. The sequence of dipping and stuccoing is repeated two times. The precoated pattern is then dipped into a composition containing 300 parts of the above binder composition, 100 partsiof zircon (200 mesh) and 300 parts of fused silica (known by the Trade Mark of Rancosil #2)~ stuccoed with a fused silica sand (known by the Trade Mark of Rancosil B), and air dried for 15 minutes. The sequence of dipping and stuccoing is repeated four times. The final coat is dried for from 1 to 3 hours, dewaxed at a temperature of 200C.
and then fired at a temperature of 1000C. A shell mold free of imper-fections is obtained.
The procedure of Example 1 is repeated except that 122 parts of ethanolamine is employed in the preparation of the binder composition.
A shell mold having considerable strength and free of lmperfections is -obtained.
1'~ , _ g _ . '~: .
I
The procedure of Example l is repeated except that 416 parts of ethyl silicate "40" is substituted for the "condensed" ethyl silicate.
Again a suitable shell mold free of imperfections is obtairted.
The procedure of Example l is repeated except that ethylene glycol monoethyl ether is substituted for ethanol. A shell mold having the desired strength is obtained.
E~YAMPLE S ~
A shell mold is prepared in accordance with the procedure of ~--Example l except that the precoated pattern is coated with a backup coat ~-consisting of the following ingrediénts.
Ingredients Parts by Weight _ Water ~ 0.5 Silbond H~4 (the Trade Mark for a 24.0 ..
partially hydrolyzed silicate binder available from Stauffer Chemical Company) - Isopropyl alcohol 24.0 Fused silica flour (fine grain, 148.0 known by the Trade Mark of Nalcast PlW available from Nalco Chemical Company) Water is added to the Silbond H-4 and the mixture allowed to stand overnight before the alcohol and fused silica flour are added.
Approximately l to 3 milliliters of sulfuric acid is added for each gallon of seal coat slurry to neutralize the basic ingredients.
The precoated pattern of Example l is dipped into the slurry described above, excess slurry is removed and then stuccoed with a coarse fused silica flour tknown by the Trade Mark of Nalcast S-2). The dipping and stuccoing sequence is repeated four times. The coated pattern is then dried o~Ternight and the wax removed by means of a high-pres~ure steam autoclave. The resulting shell is fired at a temperature o:f 1000C.
and while still hot, molten stainless steel is poured into the cast.
The cast is then cooled and the shell is broken off by vibration. The ,n~ :
~,,, - 10 --.'.' ' :, .. ,., .,, ', castin~ showed no appreciable scaling or imperfections of any kind.
Other additives which may be incorporated in the binder com-position of aspects of this invention are boron compounds and organic acids. Examples of suitable boron compounds are boric acid and alkyl borates in which each of the alkyl groups contairs from 1 to 8 carbon atoms. The term "borate" includes any alkanol ester of any boric acid.
Suitable examples of alkyl borates ar~e trimethyl borate, triethyl borate, tripropyl borate, triisobutyl borate, trimethoxy boroxine, tri-n-butoxy boroxine, trihexoxy boroxine and the like. The borate or ~orate mixtures can be added in pure form or in solvent solution as desired.
Suitable examples of organic acids which may be added to the binder composition for preparing shell molds are organic monocarboxylic acids having from 1 to 10 carbon atoms, such as, for example, formic acid, ace~ic acid, propanoic acid, butanoic acid, hexanoic acid, octanoic acid, decanoic acid, 2-ethylbutyric acid, 2-ethylpentanoic acid, f ~ 2-ethylhexoic acid and the like.
The amount of boron compound that may be added to the binder composition ranges from 0.5 to 10 percent and more preferably from 1 to 5 percent by weight based on the weight of the binder composition. The amount of organic acid that may be added ranges from 1 to 10 percent by weight and more preferably from 1.5 to 5 percent based on the weight of the binder composition.
The addition of the boron compound and the organic acid improves the stability of the binder composition, i.e., these additives improve the shelf life and the pot life of the resultlng coating composi-tion O
.
This invention relates to a binder composition for shell molds, and more particularly to a process for the preparation of shell molds for the casting of metals.
Precision casting of metal and other types of material in the molten state is used in many industries and, generally, such castings are made in expendable molds. There are three general types of processes for making the expendable molds and these may be classified as the "lost wax", the single investment and the double investment processes. These all have one thing in common; they are one-use molds in which the mold is generally destroyed in removing the casting therefrom. To provide an economical process, a master mold or pattern is initially prepared from which refractory molds are made by one of the above processes.
In the manufacture of precision castings by investment shell casting techniques, disposable patterns are made from waxes, plastic materials, frozen mercury -and other materials which readily may be removed from the mold. The investment cycle consists of m~king the pattern by injecting the pattern material into the die and gating the pattern to a central sprue to form a pattern cluster.
Generally, the pattern cluster is dipped into an agitated slurry of the coating composition, drained, stuccoed while still wet ~
with particulate mold material and aried. The dipping, draining, stucco- ;
ing and drying sequence is repeated he desired number of times, depen-ding on the thickness and strength of the shell mold desired.
Thereafter, the disposable pattern is removed by methods such as, for example, melting or solvent treatment and the mold cured by fir-ing at a temperature sufficient to remove the volatiles and provide adequate bonding. The molds are then heated and filled with molten metal and after cooling, the castings are removed from the sprue and finished in the usual manner.
The preparation of shell molds has been described in United States Patent No. 3,270,382 issued Septe~ber 6, 1966 to Emblem et al in which two different coatings are applied alternately - 1 -' ~ '~
,. . . . .
..
,~.
;; ~
3~3~
to an expendable pattern. One coating consists of a gel-~orming acid hy-droly2ed alkyl silicate solution and the other coating consists of a gel-forming basic silicate ester. m e acid hydrolyzed solution and the basic silicate est~r o~ the applied coatings each act upon the other so as to cause gelation of the other.
In United States Patent No. 3,079,656 issued ~arch 5, 1963 to E~blem et al, the patentees describe the preparations of aminosilicates by an interchange reaction bet~^7een an alkyl silicate and an aminoalcohol, while removing the alcohol produced as the result of tne interchange reac-tion. The aminosilicates may be co~bined with a reEractory material and applied to an expendable pattern. The coating is gelled by the addition of water. Likewise, amLnoaIk~lsilicates have heen disclosed as binders in United States Patent ~o. 3,112,538 issued December 3, 1963 to Emblem et al.
The binder is combined with fine refractory powders to form a slurry which is ap~lied to a wax pattern. Each coating is allowed partially to harden before the next is applied. me coated pattern is then hardened for 24 hours before t~e wax pattern is removed. '~ -Binders containing a mixture of an alkyl silicate and an aminoalkyl silicate have been described in United S-tates Patent ~o. 3,329,520 issued July 4, 1967 to Emblem et al. These binders are combined wlth a refractory material and water and then cast into the desired s'nape.
A paint composition containing a mixture of organlc silicates and an amine having a pKa value above 7.8 is described in Australian Patent .~o. 163,467. However, wh~n the composition contains an amine such as, for . .
. .
" ' ~ ' ' . ' ' ~ ",, ' "`.'' '' ~, ' ' l~S~)8 example, monoethanolamine, the mixture must age for at least 48 hours and up to fourteen days before it can be used as a protective coating on said cores.
It is an object of one as~ect of this invention to provide a pro-cess for preparing shell molds.
An object of another aspect of this invention is to provide a pro-cess for preparing shell molds which utilize a single binder com~osition.
An object of another aspect of this invention is.to provide a pro-cess for preparing shell molds ~ich may be used after air drying for from 1 to 3 hours.
~ n object of a further aspect of this invention is to provide a binder composition which does not reouire the addition of additional water to cause gelation thereof.
An object of a still fur~her aspect of this invention is to provide a binder com~osition ~nich does not require removing the alcohol resul~ing from the esterification of an organosilicate and an aminoalcohol.
By one broad aspect, then, a coating composition is provided for the preparation of shell molds cc~prising a refractory material and a binder P
composition which is substantially free of water, the binder composition comprising a silicate ester, an ammoalcohol of the formula HOR~R')2 in which R is a divalent hydrocar~on radical having from 1 to 6 carbon atoms, Rl is selected from the group consisting of hydrogen, an alkyl radical of the formula -ROH in which R is the same as above, in which the mol ratio of anuno-alcohol to silicate ester is from 1:1 to 10:1, and an i.
'. ' . ' :, ~,, :
.
. .
;: ' ~'` .
~ 15~6~
organic solvent, thereby to form a binder composition naving an SiO2 content of from 10 to 35 percent by weight based on the weiyht of the binder.
By a preferred variant, the silicate ester comprises a prehydro-lyzed alkyl orthosilicate in which alk;yl group has from 1 to 4 carbon atoms.
By oth~r variants, the prehydrolyzed alkyl orthosilicate is ethylpolysilicate or i5 silicate "40".
By yet oth~r variants, the aminoalcohol may ~e monoetnanolamlne or triet7nanola~ine.
By another variant, the composition may include, as additional additives, at least one of boron compounds and organic acids.
By one variant, t7ne boron compound is boric acid or an alhyl bor ate in which the alkyl ~roup contains 1 to 8 carbon aton~7.
By another variant, tne acid is a mo.~car~oxylic acid haviny from -1 to 10 carbon atoms.
By another aspeot of this invention, a process is provided for preparin~ a sllell mold which comprises: coating an expendable pattern with a oQmposition containing a binder which a,$ ~ubsta7ltially Eree of ~ater and refractory material, in which the ratio of refractory material to binder is from about 4 to 50 parts of refractory naterial per part of binder SiO2, the binder ccmprisi~g a silicate ester, an a7ninoalconol of t7ne formwla HO~N (R I ) 2 in which R is a dival~nt h ~ rbon radical having from 1 bD 6 carbon atQ~s~
R' is selected from the group oonæi~ting of hydrogen, an alkyl radical and a radical o the formula -R~H in which R is the s~mei as above, in ~ 4 ~-; j , ., - . , . . , , , ~, . . ................. .. .
: . . ~:, : ~,, , which the mol ratio of aminoalcohol to silicate ester is frorn 1:1 to 10:1 and sufficient organic solvent to provide an SiO2 content of from 10 to 35 percent by weight based on the weight of the binder; stuccoing the coated pa~tern, air drying; and repeating the above sequence of steps until a coat-ing of desired thickness is achieved.
By variants thereof, the si]icate ester may be a prehydrolyzed aIkyl orthosilicate in which the alkyl group has from 1 to 4 carbon atoms or the coating composition may also contain from 0.5 to 10 percent by ~7eight based on the ~leight of the binder cornposition of an alkyl borate.
By yet another aspect, the process includes the step of applying a seal coat, said seal coat comprising a composition containing a hydrolyzed silicate ester, a refractory material an~ an organic solvent.
m e process of an aspect of this inventlon constitutes an improve-ment in investment casting over that disclosed in the art. For e~ample, the binder oQmposition of an aspec~ of this invention does not require an aging period, i.e., the composition is ready to use substantially immediately after muxing the lngredients. rloreover, the resulting shell is ready for r use after air drying for from one to three .~ours. Also, the binder oom-position of an aspect of this invention gels in the presence of atmosp.~eric moisture and does not require adding additional water to the binder com~
position. In addition, the process of an aspect of this invention utilizes a single binder composition to prepare shell molds, whereas many of the shell molds prepared heretofore required at least two different types of binder compositions.
~ ~ 4 a - _ ~ `
'. :: :
:
i~5~
ccording to one varian-t and e~bodiment of this invention, previ-ously claimed and e~ched disposable patterns are coated with a binder com~
position containing a refractory material. s-tuccoing with a coarse refractory material and then dried to set the coating material. The sequence of steps is repeated until the desired eoating tnickness is achieved. The coated pattern thus formed may be sealed with a backup coating containing a hy-drolyzed silicate ester, a solvent and a refractory material, if desired.
The sllicate esters found to be useful in providing compositions r`
of aspects~f the present invention are tetraethyl orthosilicate, "condensed"
ethyl silicate and ethyl silicate "40". "Condensed" ethyl silicate is tetraethyl orthosilicate containing 10 percent polysilicates and is the un-distilled reaction product of silicon tetrachloride and 200-proof ethanol having a nominal composition of from 2 to 5 percent ethanol, 90 to 95 per-cent orthosilicate and from 5 to 10 percent polyethoxy polysilicates.
Ethyl silicate "40" is a mixture of polysilicates averaging 5 silicon atoms per m~lecule having a siliea content of 40 percent~ It is formed by reaet-ing silicon tetrachloride ~ith ethanol containing some water under conditions r such that a silica content of 40 percent is achieved. Other silicate esters which may be ~mployed are those that - 4 b -: - .'. , !, , ," ' ' , `' ~' ~ , ' ' ' ':,,, ' .:, ' . . , . : ' ~
~L~S.~ 8 are obtained from the hydrolysis and condensation of ethyl silicate "40".
Aminoalcohols which ma~ be employed in the binder composition of an aspect of this invention may be represented by the formula HORN(R')2 where R is a divalent hydrocarbon radical having from 1 to 6 carbon atoms, R' is hydrogen or an alkyl group having from 1 to 6 carbon atoms or a group of the formula -ROH in which R is the same as above.
Examples of suitable aminoalcohols are mono-, di-, or triethanolamine, monoisopropanolamine, 2-amino-butan-1-ol, 3-amino-propan-1-ol, 2-dimethyl-amino-2-methylpropan-1-ol and the like.
Any organic solvent which is a mutual solvent for the silicate ester and the aminoalcohol may be employed. It is preferred that the solvent have a boiling point below 250~C. and more preferably below 150C.
Examples of suitable organic solvents are aliphatic alcohols, such as, for example, methanol, ethanol, isopropanol, butanol; ketones, such as, for example, acetone, methyl ethyl ketone and aromatic hydroca~bons such as, for example, benzene, toluene and the like. Polyethers which may be employed as solvents in the binder composition of an aspect of this invention are glycol ethers such as, for example, monoalkylene glycol monoalkyl ethers, dialkylene glycol monoalkyl ethers 3 dialkylene glycol dialkyl ethers and monoalkylene glycol dialkyl ethers. Examples of preferred glycol ethers are ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol dibutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, and esters of the ethylene glycols such as, for example, ethylene glycol monobutyl ether acetate, ethylene glycol mono-methyl ether acetate and the like.
The amount of aminoalcohol employed in the binder composition of an aspect of this invention is not critical. It can be present in a mol ratio of aminoalcohol to ethyl silicate of from 1:1 to lO:l and more preferably from 3:1 to 8:1.
Generally the amount of silicate esters employed in the binder composition of an aspect of this invention is sufficient to provide a binder having an SiO2 content of the order from 10 to 35 percent and more preferably from 15 to 30 percent by weight bas d on the weight of the binder composition.
Refractory materials which may be employed in the binder com-position of an aspect of this invention are many and varied. Generally, well-known refractories such as, for example, the oxides and silicates -- -of silicon, alumina, zirconium, zinc, magnesium, chromium and titanium may be used. These include the acidic minerals, the neutral or amphot-10 eric minerals, especially those whose primary elements are found in Group II of the Periodic Table, the gel acid minerals, e.g., allophane and the basic minerals, e.g., zirkelite. Also, there should be mentioned the many synthetic materials including the zeolites, molecular sieves, ion-exchange resins and similar substances. Apart from the foregoing, zircon, grog, calcined clay, silica flour, sand anf fused silica may be used providing compositions of aspects of t~is invention. Examples of acidic, weakly acidic or neutral amphoteric minerals are fused silica, natural silica, zircon, stillimanite, zirconite, whicll is a mixture of silicates and oxides of zircon; mullite which is a high refractory 20 aluminum silicate, clays, magnesia9 and other metal oxides and silicates.
These refractory materials may be employed alone or in com-bination depending on the particular casting operation contemplated.
Also, the particle size of the refractory material is selected depending on the specific purpose for which the mold is being fabricated. In some cases, it is desirable to employ a mixture containing both relatively coarse and fine particles. G~nerally, a coarser refractory material is used in the stuccoing step than is used in the initial coating composi-tions, thereby providing a bond betweén one shell coat and the succes-sive coat.
A shell mold conforming to an aspect of this invention is pro-duced without the use of any other binder than the one described as an aspect of this invention. However, where a seal coat or backup coat is ' ' ' ': : , :
1~5160~
desired a bin~er composition containing a refractory material and sili-cate esters such as, for example, the prehydrolyzed type commercially available or those prepared by the acid hydrolysis of any of the commer-cially available forms of ethyl silicate, includinE monomeric orthosili-cate, "condensed" ethyl silicate or ethyl silicate "40" may be employed.
To prevent premature gelation of the seal coat composition, a small quantity of acid having an acidity greater than that of the hydrolyzed ethyl silicate or an acidic buffering agent can be added to the binder solution. The p~ oE the seal coat composition should be maintained in the range from 1 to 3.2. Suitable acids and buffering agents include hydrochloric acid, phosphoric acid, sulfuric acid, and ammonium nitrate. The quantity of acid or buffering agent employed will vary depending upon the acid or buffering agent used and the refractory aterial present in the composition.
The same refraGtory materials which were employed in the prior - coating composition may be used in the seal coat. Generally, these refractory materials are oxides and silicates of silicon, alumina, zirconium, zinc, tin, magnesium, chromium, titanium and the like. ~ther refractory materials such as, for example, grog, calcined clay, silica flour, sand or fused silica may also be used in the seal coat composi-tion.
These refractory materials may be employed ~everally or in any combination deemed desirable depending on the particular casting opera-tion contemplated.
The same solvents which were used in the initial coating com-position described above may be used in the seal coat. Examples of suitable solvents are the alcohols, ketones and polyethers such as, for example, the monoalkylene glycols monoalkyl ethers, dialkylene glycols monoalkyl ethers, monoalkylene glycols dialkyl ethers and dialkylene glycols dialkyl ethers.
The amount of binder employed in the coating composition is substantially determined by the particle size of the refractory materials . . .
~(~s~
since the finer the refractory material the more readily it absorbs the binder 9 hence the more binder required. In some cases where the refractory particles are coarse, the amount of binder required may be such that for every 100 parts refract:ory material there may be used only that amount of binder necessary to provide 1 part of binder SiO2. Con-versely, where the particles of refractory material are extremely fine it may be necessary to use with each 4 parts of refractory material that amount of binder necessary to provide 1 part of binder SiO2. In other words, the ratio of refractory material to binder may range from 4 to 100 parts refractory material per part of binder SiO2.
In general, the seal coat composition is applied to the pre-viously dried coating and then dried in the presence of atmospheric moisture. In the event it is desired to accelerate the gelling of the seal coat,` then a basic material su~h as, for example, ammonia or ~ -organic amines such as, for example, aliphatic, aromatic and cyclic amines having up to 10 carbon atoms may be employed. Examples of suit-able amlnes are methylamine, mono-, di- and triethylamines, propylamine, n-butylamine, cyclohexylamine, hydrazine, piperidine, and the like.
After the pattern has been covered with the desired number of coats, it is dried at a temperature which may vary from 25C. up to the fluidizing temperature of the disposable pattern. The temperature may then be increased in a nonoxidizing atmosphere to fluidize and remove the disposable pattern therefrom. The resulting shell mold is subse-quently fired by exposure to a temperature of from 500 to 3000~C. in an oxidizing atmosphere for from 1 to 12 hours.
Various aspects of the invention are illustrated by the follow-ing examples in which all parts are by weight unless otherwise specified.
A wax tree pattern is sprued and gated to conform to the requirements of the metal cast and casting desired. The tree is momen-tarily etched in a 75 percent trichloroethylene - 25 percent isopropyl alcohol mixture and the excess removed with isopropyl alcohol. The .
p~ttern is allowed to dry before dipping into a coating composition prepared in the following manner:
Binder Composition Ingredients Parts Ethyl silicate (condensed) ~ 416 Ethanol 540 Ethanolamine 244 The binder composition is prepared by adding with agitation ethanolamine to a solution containing "condensed" ethyl qilicate and ethanol at a temperature of from 40 to 45C. The solution i8 stirred for one hour at this temperature, cooled to 30C. and filtered.
Approximately 300 parts of the binder composition prepared above is mixed with 200 parts of ziroon (325 mesh) and 400 parts of fused silica (available from Ransom and Randolph Company and identified by the Trade Mark Rancosil #l) to form a slurry. The wax pattern is coated with the slurry, stuccoed with a fused silica sand (available from Ransom & Randolph Co~pany and identified by the Trade Mark Rancosil A) and air dried for 15 minutes. The sequence of dipping and stuccoing is repeated two times. The precoated pattern is then dipped into a composition containing 300 parts of the above binder composition, 100 partsiof zircon (200 mesh) and 300 parts of fused silica (known by the Trade Mark of Rancosil #2)~ stuccoed with a fused silica sand (known by the Trade Mark of Rancosil B), and air dried for 15 minutes. The sequence of dipping and stuccoing is repeated four times. The final coat is dried for from 1 to 3 hours, dewaxed at a temperature of 200C.
and then fired at a temperature of 1000C. A shell mold free of imper-fections is obtained.
The procedure of Example 1 is repeated except that 122 parts of ethanolamine is employed in the preparation of the binder composition.
A shell mold having considerable strength and free of lmperfections is -obtained.
1'~ , _ g _ . '~: .
I
The procedure of Example l is repeated except that 416 parts of ethyl silicate "40" is substituted for the "condensed" ethyl silicate.
Again a suitable shell mold free of imperfections is obtairted.
The procedure of Example l is repeated except that ethylene glycol monoethyl ether is substituted for ethanol. A shell mold having the desired strength is obtained.
E~YAMPLE S ~
A shell mold is prepared in accordance with the procedure of ~--Example l except that the precoated pattern is coated with a backup coat ~-consisting of the following ingrediénts.
Ingredients Parts by Weight _ Water ~ 0.5 Silbond H~4 (the Trade Mark for a 24.0 ..
partially hydrolyzed silicate binder available from Stauffer Chemical Company) - Isopropyl alcohol 24.0 Fused silica flour (fine grain, 148.0 known by the Trade Mark of Nalcast PlW available from Nalco Chemical Company) Water is added to the Silbond H-4 and the mixture allowed to stand overnight before the alcohol and fused silica flour are added.
Approximately l to 3 milliliters of sulfuric acid is added for each gallon of seal coat slurry to neutralize the basic ingredients.
The precoated pattern of Example l is dipped into the slurry described above, excess slurry is removed and then stuccoed with a coarse fused silica flour tknown by the Trade Mark of Nalcast S-2). The dipping and stuccoing sequence is repeated four times. The coated pattern is then dried o~Ternight and the wax removed by means of a high-pres~ure steam autoclave. The resulting shell is fired at a temperature o:f 1000C.
and while still hot, molten stainless steel is poured into the cast.
The cast is then cooled and the shell is broken off by vibration. The ,n~ :
~,,, - 10 --.'.' ' :, .. ,., .,, ', castin~ showed no appreciable scaling or imperfections of any kind.
Other additives which may be incorporated in the binder com-position of aspects of this invention are boron compounds and organic acids. Examples of suitable boron compounds are boric acid and alkyl borates in which each of the alkyl groups contairs from 1 to 8 carbon atoms. The term "borate" includes any alkanol ester of any boric acid.
Suitable examples of alkyl borates ar~e trimethyl borate, triethyl borate, tripropyl borate, triisobutyl borate, trimethoxy boroxine, tri-n-butoxy boroxine, trihexoxy boroxine and the like. The borate or ~orate mixtures can be added in pure form or in solvent solution as desired.
Suitable examples of organic acids which may be added to the binder composition for preparing shell molds are organic monocarboxylic acids having from 1 to 10 carbon atoms, such as, for example, formic acid, ace~ic acid, propanoic acid, butanoic acid, hexanoic acid, octanoic acid, decanoic acid, 2-ethylbutyric acid, 2-ethylpentanoic acid, f ~ 2-ethylhexoic acid and the like.
The amount of boron compound that may be added to the binder composition ranges from 0.5 to 10 percent and more preferably from 1 to 5 percent by weight based on the weight of the binder composition. The amount of organic acid that may be added ranges from 1 to 10 percent by weight and more preferably from 1.5 to 5 percent based on the weight of the binder composition.
The addition of the boron compound and the organic acid improves the stability of the binder composition, i.e., these additives improve the shelf life and the pot life of the resultlng coating composi-tion O
.
Claims (13)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A coating composition for the preparation of shell molds comprising a refractory material and a binder composition which is substantially free of water, said binder composition comprising a silicate ester, an amino-alcohol of the formula HORN(R')2 in which R is a divalent hydrocarbon radical having from 1 to 6 carbon atoms, R' is selected from the group consisting of hydrogen, an alkyl radical or a radical of the formula -ROH in which R is the same as above, in which the mol ratio of aminoalcohol to silicate ester is from 1:1 to 10:1, and an organic solvent, thereby to form a binder composition having an SiO2 content of from 10 to 35 percent by weight based on the weight of the binder.
2. The coating composition of claim 1 wherein said silicate ester comprises a prehydrolyzed alkyl orthosilicate in which the alkyl group has from 1 to 4 carbon atoms.
3. The composition of claim 2 wherein said pre-hydrolyzed alkyl orthosilicate is ethylpolysilicate.
4. The composition of claim 2 wherein said pre-hydrolyzed alkyl silicate is silicate "40".
5. The composition of claims 1, 2 or 3 wherein the aminoalcohol is monoethanolamine.
6. The composition of claims 1, 2 or 3 wherein the aminoalcohol is triethanolamine.
7. The composition of claims 1, 2 or 3 including therein, as additional additives, at least one of boron compounds and organic acids.
8. The composition of claims 1, 2 or 3 including therein, as additional additives, at least one of boron compounds and organic acids and wherein said boron compound is boric acid or an alkyl borate in which the alkyl group contains 1 to 8 carbon atoms.
9. The composition of claims 1, 2 or 3 including therein, as additional additives, at least one of boron compounds and organic acids and wherein said acid is a monocarboxylic acid having from 1 to 10 carbon atoms.
10. A process for preparing a shell mold which comprises: coating an expendable pattern with a composition containing a binder which is substantially free of water and a refractory material, in which the ratio of refractory material to binder is from about 4 to 50 parts of refractory material per part of binder SiO2, said binder comprising a silicate ester, an aminoalcohol of the formula HORN(R')2 in which R is a divalent hydrocarbon radical having from 1 to 6 carbon atoms, R' is selected from the group consisting of hydrogen, an alkyl radical and a radical of the formula -ROH in which R is the same as above, in which the mol ratio of aminoalcohol to silicate ester is from 1:1 to 10:1 and sufficient organic solvent to provide an SiO2 content of from 10 to 35 percent by weight based on the weight of the binder; stuccoing the coated pattern; air drying; and repeating the above sequence of steps until a coating of desired thickness is achieved.
11. The process of claim 10 wherein said silicate ester comprises a prehydrolyzed alkyl orthosilicate in which the alkyl group has from 1 to 11 carbon atoms.
12. The process of claims 10 or 11 wherein the coating composition contains from 0.5 to 10 percent by weight based on the weight of the binder composition of an alkyl borate.
13. The process of claims 10 or 11 including the step of applying a seal coat, said seal coat comprising a composition containing a hydrolyzed silicate ester, a refractory material and an organic solvent.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US48986774A | 1974-07-18 | 1974-07-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1051608A true CA1051608A (en) | 1979-04-03 |
Family
ID=23945593
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA231,708A Expired CA1051608A (en) | 1974-07-18 | 1975-07-17 | Preparation of high temperature shell molds |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS5117118A (en) |
| BE (1) | BE831539A (en) |
| CA (1) | CA1051608A (en) |
| DE (1) | DE2531001A1 (en) |
| FR (1) | FR2278422A1 (en) |
| GB (1) | GB1508020A (en) |
| IT (1) | IT1045563B (en) |
| NL (1) | NL7508625A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02165840A (en) * | 1988-12-20 | 1990-06-26 | M D Kasei Kk | Molding material for sand mold for casting and production of sand mold for casting |
-
1975
- 1975-06-23 JP JP50075786A patent/JPS5117118A/ja active Pending
- 1975-07-11 DE DE19752531001 patent/DE2531001A1/en not_active Withdrawn
- 1975-07-15 FR FR7522048A patent/FR2278422A1/en not_active Withdrawn
- 1975-07-16 IT IT50543/75A patent/IT1045563B/en active
- 1975-07-17 CA CA231,708A patent/CA1051608A/en not_active Expired
- 1975-07-17 GB GB30059/75A patent/GB1508020A/en not_active Expired
- 1975-07-18 NL NL7508625A patent/NL7508625A/en not_active Application Discontinuation
- 1975-07-18 BE BE158446A patent/BE831539A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| BE831539A (en) | 1976-01-19 |
| DE2531001A1 (en) | 1976-02-05 |
| GB1508020A (en) | 1978-04-19 |
| NL7508625A (en) | 1976-01-20 |
| IT1045563B (en) | 1980-06-10 |
| FR2278422A1 (en) | 1976-02-13 |
| JPS5117118A (en) | 1976-02-10 |
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