US3216075A - Method for manufacturing foundry cores and molds - Google Patents

Method for manufacturing foundry cores and molds Download PDF

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Publication number
US3216075A
US3216075A US256408A US25640863A US3216075A US 3216075 A US3216075 A US 3216075A US 256408 A US256408 A US 256408A US 25640863 A US25640863 A US 25640863A US 3216075 A US3216075 A US 3216075A
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Prior art keywords
binder
weight
formaldehyde
furfuryl alcohol
sand
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Lloyd H Brown
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Quaker Oats Co
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Quaker Oats Co
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Priority to NL295300D priority Critical patent/NL295300A/xx
Application filed by Quaker Oats Co filed Critical Quaker Oats Co
Priority to US256408A priority patent/US3216075A/en
Priority to GB29484/63A priority patent/GB1000671A/en
Priority to CH943063A priority patent/CH458637A/de
Priority to BR151234/63A priority patent/BR6351234D0/pt
Priority to AT610263A priority patent/AT251778B/de
Priority to LU45330D priority patent/LU45330A1/xx
Priority to FR962433A priority patent/FR1388184A/fr
Priority to ES296046A priority patent/ES296046A1/es
Priority to BE643423D priority patent/BE643423A/xx
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    • 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
    • B22C1/22—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 of resins or rosins
    • B22C1/2233—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 of resins or rosins obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • B22C1/224—Furan polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C23/00—Tools; Devices not mentioned before for moulding

Definitions

  • This invention relates to a new and useful method for the high-speed manufacture of foundry cores and molds.
  • the method of this invention utilizes a special binder and produces cores and molds having high cold strength, high hot strength, and low gas evolution.
  • This method produces cores and molds which lead to iron and steel castings in which pinholes are virtually absent.
  • a high-speed foundry core and mold making process, particularly one utilizing automatic equipment, is possible only when a complex balance of properties has been achieved in the sand binders.
  • The. binders must be stable enough to permit convenient room temperature storage before and after mixing with sand, yet set or harden very quickly when applied to a core box or mold.
  • binders of the prior art which can be set or hardened quickly are sensitive in regard to overand under-cure, which can be accompanied by serious diminishing of strength.
  • a process for the high-speed production of cores and molds demands a binder which is not particularly subject to underor over-cure.
  • binder employed in a particular process must impart sufficient strength to the sand core or mold to enable it to withstand the destructive forces resulting .from the density and motion of the metal being poured,
  • An object of the present invention is to provide a comparatively inexpensive method for the high-speed production of foundry cores and molds which are suitable for the production of substantially pinhole-free nodular iron and steel castings.
  • Another object of this invention is to provide a method for production of said cores and molds which requires a very short dwell time, thereby providing for correspond 3,216,075 Patented Nov. 9, 1965 ice ingly high rate of production in terms of units produced per core box or pattern per unit time.
  • a further object of this invention is to provide a method which utilizes a binder which is stable at ordinary room temperatures, yet is extremely reactive and fast curing when used in accordance with the process of this invention, and yet is not sensitive to overor under-cure.
  • a still further object of this invention is to provide a method which leads to sand cores or molds which have a high degree of cold strength, and moreover have a high degree of strength at pour temperatures.
  • Another object of this invention is to provide a method for making cores and molds which is readily adaptable to the increasingly important high-speed, automatic, mechanized foundry operations.
  • a further object of this invention is to provide a method for high-speed manufacture of cores and molds which is readily applicable to a wide variety of foundry sands, despite the wide range of alkalinity and acidity which can normally be encountered in these materials.
  • Another object of this invention is to provide a method which does not require the use of curing ovens.
  • the special binder employed by the method of this invention is a substantially anhydrous, nitrogen-free mixture comprising a boron-containing component in an amount between 5% and 40% by weight based on the weight of the binder, and a second component which is either (a) a mixture of acid catalyst in an amount between 0.5% and 15% by weight based on the weight of said mixture, and a liquid furfuryl alcohol-formaldehyde composition in an amount between 99.5% and by weight based on the weight of said mixture, said composition containing at least 15% by weight furfuryl alcohol monomer, and having between about 2% and 30% formaldehyde level, as defined hereinafter, or (b) a liquid furfuryl alcohol-formaldehyde composition containing at least 15% by weight furfuryl alcohol monomer and having between about 12 and about 30% by weight formaldehyde level.
  • the method of this invention comprises the following steps:
  • step 2 (2) applying foundry mix provided by step 1 to a shaped, heated surface, such as that of a core box or pattern, said surface being at a temperature between 350 and 600 F.;
  • boron-containing component herein refers to either single compounds or mixtures of compounds including boron oxides, such as the anhydride B 0 the various acids which reflect the various degrees of hydra tion of boron oxides, and the lower oxy acids of boron.
  • Boron oxide (B 0 and boric acid (H BO are commercially available and are eminently satisfactory boroncontaining components in the binder of this invention.
  • the special binders of this invention containing between 15% and 25% (by weight based on the weight of the binder) of boron oxide, or of boric acid, or of a mixture of boron oxide and boric acid, are preferred.
  • acid catalyst refers to relatively strongly acidic materials which are capable of catalyzing the polymerization of the special binder of this invention.
  • Strong mineral acids such as phosphoric acid, hydrochloric acid and many organic acids
  • anhydrides such as citric acid and maleic anhydride
  • boric acid are suitable catalysts.
  • Weak acids such as boric acid
  • Other acidic materials such as BCl FeCl AlCl etc., also have some utility as catalysts.
  • Phosphoric acid and citric acid are the preferred acid catalysts.
  • an, acid catalyst When used, it is preferred that it be used in an amount between 3% and 9% by weight based on the weight of the mixture of the catalyst and furfuryl alcohol-formaldehyde composition used therewith.
  • Primary or secondary amine salts e.g., NH OH-HCI, are also useful catalysts. Since the catalysts are present in low concentrations, the binders utilizing the amine salts are considered substantially nitrogen-free.
  • liquid furfuryl alcohol-formaldehyde composition refers to a mixture containing at least 15 furfuryl alcohol monomer by weight and also free formaldehyde or furfuryl alcohol-formaldehyde resin, or both.
  • a preferred liquid furfuryl alcohol-formaldehyde composition contains between 30% and 60% furfuryl alcohol by weight based on the weight of the composition.
  • the formaldehyde ingredient may be supplied by dissolved anhydrous formaldehyde or trioxane. Although paraform is a less desirable source of free formaldehyde since it contains some water of hydration, it can be used for this purpose provided it does not raise the water content of the binder over by weight.
  • Aqueous solutions of formaldehyde, such as formalin, should not be used directly as an ingredient of the furfuryl alcohol-formaldehyde composition because of the water present but, of course, may be used in the preparation of the substantially anhydrous furfuryl alcohol-formaldehyde resinsa Substantially anhydrous, nonnitrogencontaining formaldehyde polymers and/or furfuryl alcohol polymer may also be included in the liquid furfuryl alcohol-formaldehyde composition employed in this invention.
  • furfuryl alcohol-formaldehyde resin herein refers to any of the substantially anhydrous nonnitrogen-containing furfuryl alcohol-formaldehyde resins well known to the art. These resins are generally prepared by the steps: (1) catalyzed condensation of furfuryl alcohol and formaldehyde, (2) deactivation of the catalyst, and (3) distillation to remove ingredient water and water of reaction. Any of the nonnitrogen-containing sources of formaldehyde may be utilized in preparation of the resin, e.g., paraform, trioxane, anhydrous formaldehyde, and aqueous solutions, such as formalin. Substantially all of the water added by way of ingredients, as well as water formed during preparation of the resin, should be removed.
  • Furfuryl alcohol-formaldehyde resins such as those produced in accordance with procedures comparable to those disclosed in US. Patent No. 2,874,148 and in US. Patent No. 2,343,972, are commercially available today and are eminently satisfactory in the special binder of this invention.
  • the resinification reaction is terminated at early stages, much of the unreacted furfuryl alcohol monomer will still be present.
  • the viscosity reaches about 2000 centipoises (cps.) sufficient furfuryl alcohol monomer will remain unreacted to provide more than the 15% furfuryl alcohol monomer required by the special binder of this invention.
  • furfuryl alcohol-formaldehyde compositions which contain less than 0.5% unreacted formaldehyde by weight based on the weight of the composition. Such compositions containing furfuryl alcohol-formaldehyde resin in an amount between about 20% and 60% by weight are preferred.
  • substantially anhydrous is meant that the water content is preferably as low as possible, and should not exceed about 5%, based on the weight of the binder.
  • foundry sand must be substantially dry. Use of wet sand leads to undesirable gas formation during pouring but also has a decidedly detrimental effect on the strength of the cores or molds.
  • the formaldehyde level of a composition or mixture as used herein is defined as the total weight of formaldehyde added at any time as an ingredient per parts by weight of the composition or mixture.
  • the weight of formaldehyde includes formaldehyde equivalent added in the form of trioxane, paraform, formalin, furfuryl alcohol-formaldehyde resin, etc.
  • formaldehyde level is obviously empirical in that the formaldehyde may not be present as such in some of the binders of this invention.
  • the formaldehyde may be free, of course, but as hereinbefore indicated, it is preferred that the formaldehyde be incorporated into furfuryl alcohol-formaldehyde resin.
  • Example 1 To illustrate this definition of the formaldehyde level term, it is seen in Example 1 below that 6 parts of formaldehyde were used as an ingredient to produce 73.2 parts of furfuryl alcohol-formaldehyde resin. Hence, the formaldehyde level of the resin is 8.2% based on the weight of the resin. When this resin is diluted 50--50 with furfuryl alcohol, the resulting mixture has a formaldehyde level of 4.1% based on the weight of the mixture.
  • Furfuryl alcohol-formaldehyde resins having formaldehyde levels substantially above 30% are very ditficult to prepare. Further, formaldehyde may be forced into a composition, e.g., by adding paraform, but we have found that this formaldehyde is lost rapidly and leads to severe odor problems.
  • FIGURE 1 shows the tensile strength of cured cores (produced in accordance with this invention), plotted against the dwell times utilized in two series of tests. Each series utilized a different embodiment of the special binder of this invention in an amount of 2% by weight based on the weight of the sand. Both embodiments of the special binder contained 20% boric acid by weight based on the weight of the binder.
  • the embodiment of the special binder of this invention utilized in series A of FIGURE 1 contained no catalyst, but had a formaldehyde level of about 16%.
  • the furfuryl alcohol-formaldehyde composition of this binder contained 70% furfuryl alcohol-formaldehyde resins and 30% furfuryl alcohol monomer.
  • the embodiment of the special binder of this invention utilized in series B of FIG- URE 1 contained phosphoric acid in the amount of 5% by weight based on the weight of the binder, had a formaldehyde level of about 3%, and the furfuryl alcoholformaldehyde composition utilized therein had 50% furfuryl alcohol-formaldehyde resin and 50% furfuryl alcohol monomer.
  • FIG. 2 illustrates the relationship between formaldehyde level and dwell time required in order that the cured core (produced in accordance with this invention) achieve a tensile strength of 200 p.s.i.
  • the latter tensile strength is chosen merely for the purpose of illustration in that it appears to be a minimal tensile strength which is suitable for many foundry purposes. It is obvious from the data herein that strengths amounting to twice this value are commonly obtained and can be reproducibly obtained by the process of this invention (see Example 6).
  • the cores tested to provide the information summarized in FIG. 2 were produced in accordance with this invention, and utilized 2% binder, based on the weight of the sand, 20% boric acid, based on the weight of the binder, and were prepared in a 450 F.
  • FIG. 2 further shows that the presence of the acid in the special binder does speed up the rate of strength formation but that excellent results were achieved with no catalyst at all.
  • the special binder as defined herein, is utilized. It is seen from Table VI below that, even in the presence of 5% acid catalyst, the binder consisting essentially of highly reactive furfuryl alcohol monomerpolymer mixture having zero formaldehyde level leads to a tensile strength of only 120 p.s.i.
  • An acid catalyzed binder consisting essentially of furfuryl alcohol monomer-free polymer, also having zero formaldehyde level, provides zero tensile strength in a parallel test.
  • the method of this invention is readily applicable to a wide variety of sands despite the wide range of acidity and alkalinity normally encountered thereon.
  • sands contaminated with highly alkaline substances should be washed before use in this invention.
  • the binder ingredients may be mixed prior to addition to the sand with the exception of the acid catalyst ingredient, if employed, or the ingredients may be mixed after addition of the individual ingredients to the sand.
  • proper quantities of boric acid, furfuryl alcohol monomer, and furfuryl alcohol formaldehyde resin are mixed prior to their addition to the sand.
  • the same materials are added individually to the sand and mixed thereon by mulling.
  • these ingredients may either be premixed with the other ingredients or added to the sand individually with the other ingredients and mixed thereon.
  • the acid catalyst ingredient should be added only to the sand -before, during or after the addition of the other binder ingredients to the sand.
  • the mixing action provided by commercial mullers is satisfactory. The advantages of continuing mixing until the binder is substantially uniformly distributed on the sand are considered obvious.
  • the term wet as applied to sand mixes indicates that a liquid binder is employed. It has been emphasized elsewhere herein that the special binder of this invention is substantially anhydrous.
  • the wet, shapable, hardenable sand mix provided by step 1 of the process of this invention may be applied to a pattern or core box or the like in any suitable manner. Conventional sand slingers and sand blowers are very satisfactory.
  • the core box or pattern is heated by any convenient means to provide temperatures at their sand-contacting surfaces between about 350 F. and about 600 F Temperatures between about 400 and 500 F. are preferred.
  • the method of this invention is particularly suited to the production of cores, shell cores, and shell molds.
  • foundry mix provided by step 1 of this invention is (a) blown between heated, matched patterns, the sand-contacting surfaces of the patterns having a temperature between 350 F. and 600 F (b) the foundry mix is permitted to dwell between the matched patterns for a period of time suf ficient to allow the foundry mix to become a self-supporting foundry shape, (c) the foundry shape is separated from the patterns, and (d) the foundry shape is cured at ambient room temperatures for at least 30 minutes,
  • the foundry provided by step 1 is (a) blown onto a shaped, heated surface in a core box, the surface having a temperature between 35 0 F. and 600 F., (b) 'the foundry mix is permitted to dwell in the core box for a time not less than about 10 seconds nor more than about 40 seconds, during which time the mix becomes a nonshapab-le, handleable, self-supporting foundry core, (0) the core is separated from the core box, and (d) the core is cured at ambient room temperatures for at least 30 minutes.
  • handleable is meant capable of being handled without damage to shape.
  • the sand mix is allowed to dwell in contact with the shaped, heated surface for a period of time between 5 and 45 seconds if the shell has cross sections amounting to about two inches or less. Thicker, and consequently heavier, shells or molds may require longer times, up to about three minutes. The vast majority of cores and molds made by the high-speed mechanized processes appear to have cross sections of about two inches or less.
  • dwell time refers to the duration of time in which the sand mix is allowed to remain in contact with the heated surface of the core box, pattern, etc.
  • dwell time values reported herein in connection with the sand-blowing embodiments indicate the time lapse between the termination of the sand injection and the ejection of the hardened sand shape from the core box or pattern.
  • a wet sand mix is not ideally suited to the dump shell method of forming molds.
  • the dump shell forming methods usually employ dry (i.e., solid, not liquid) resin binders.
  • dry resin binders In the dump method an excess quantity of sand-resin mix is dumped onto the heated pattern surface and allowed to dwell thereon until a sand shell hardens. Thereafter the filled heated pattern is inverted and the nonhardened sand resin mix falls out, leaving a sand shell mold attached to the pattern.
  • a wet sand mix may have sufficient green strength to be self supporting in the sense that a childs sand castle on the beach is self supporting. Such a structure or sand shape is not handleable, however, as is evidenced by the disastrous consequences of an attempt to lift or tip over the sand castle.
  • wet sand foundry shapes are generally not self supporting or handleable in the sense that they cannot be manipulated by foundry machinery after or during ejection of the shape. from the core box or pattern. In the process of this invention two changes take place in the wet sand mix as a consequence of dwelling in contact with the heated pattern or core box. First, the binder sets sufficiently for the sand mix to become a self-supporting, handleable, unitary sand shape.
  • the unitary sand shape can then be manipulated or handled by foundry machinery during and after ejection from the core box or pattern.
  • the not completely understood curing reactions begin at an accelerated rate. It must be made clear that the brief dwell time does not cure the binder. The curing process is triggered by the brief dwell in contact with the heated surface, and the cure is completed after approximately one-half to one hour at ambient room temperature conditions. A one-half-hour cure is satisfactory in most cases. Hence, the curing operation requires no additional heating equipment, such as ovens or the like.
  • core box and pattern costs are not negligible, the high rate of production of cores and molds in terms of units produced per core box or pattern per unit time is most advantageous.
  • EXAMPLE 1 'Furfuryl alcohol (78.4 lbs.), 37% formalin solution (16.24 lbs.), and oxalic acid (40 grams) are charged to la jacketed kettle equipped with anchor-type stirrer and thermometer and a reflux condenser. While stirring, the temperature of the kettle contents was raised to 100 C. over a period of 45 minutes by means of steam in the jacket. At this point an exothermic reaction became obvious, and it was necessary .to maintain cooling by circulating water in the jacket for minutes. After another hour and a quarter it was necessary to introduce steam into the jacket to maintain reflux.
  • the kettle charge was then neutralized with 132 grams of triethanolamine. Water was distilled off at atmospheric pressure until the still charge reached 140 C. The viscosity of the resulting 73.7 pounds of resin was 5600 centipoises at 40 C. A 56.4-p ound portion of this resin was mixed with 54 pounds 3 ounces of furfuryl alcohol monomer to give a viscosity of 180 centipoises at 25 C. This mixture was used as a binder ingredient in accord with the process of this invention and proved eminently satisfactory.
  • EXAMPLE 2 A portion (1.5 parts) of the mixture produced by Example 1 was mulled with silica sand (98.5 parts). Phosphoric acid (0.0011 part) and boric acid (0.015 part) were also added to the sand, and the mixture was mulled until an apparently uniform mixture was obtained. Portions of this mixture were blown into test core boxes heated to 450 F. Hardened, unitary, handleable test cores were ejected therefrom after thirty seconds dwell time. After one-half to one hour cure at ambient room temperature conditions, the cores were tested and found to have tensile strengths of 400-450 p.s.i.
  • EXAMPLE 4 A sand mix was prepared by mulling 2300 parts of sand and 5 parts of aqueous 85% phosphoric acid for one minute, then mulling in 50 parts of the furfuryl alcoholformaldehyde composition produced by Example 3 for three additional minutes. Note that no boric acid was used in the preparation of the mix. Portions of this mix were blown into core boxes heated to 350 F. Some test cores produced had been subjected to ten seconds dwell time, others to thirty seconds dwell time. After 24 hours cure at dry ambient room temperature conditions, those having ten seconds dwell time showed an average tensile strength of 144 p.s.i. and those cores subjected to thirty seconds dwell time showed an average tensile strength of 154 p.s.i.
  • EXAMPLE 5 amounts of sand, boric acid, and phosphoric acid.
  • percent boric acid, formaldehyde level, and percent catalyst indicated in Table I below are based on the weight of binder. Cores were prepared from each mix utilizing ten, twenty, and thirty second dwell times. After about 45 minutes cure, the p.s.i. tensile strength of each was determined, and average values obtained are in Table I.
  • a resin was prepared in a manner similar to Example 3 except that 1.0 mole of formaldehyde was incorporated per mole of furfuryl alcohol to provide a formaldehyde level of approximately 27% in the final substantially anhydrous mixture.
  • the resinification reaction was terminated When a viscosity of 1000 centipoises at 25 C. was obtained.
  • a small sample of substantially anhydrous product was subjected to low-vacuum distillation in order to remove volatiles. The distillate was further fractionated to give quantities of furfuryl alcohol monomer, furfuryl alcohol dimer and difurfuryl ether which indicated that these compounds were present in the substantially anhydrous product in amounts by weight of about 25%, 15% and 5%, respectively.
  • a furfuryl alcohol-formaldehyde resin containing 0.5 mole formaldehyde per mole furfuryl alcohol was prepared by a procedure similar to that of Example 1.
  • the substantially anhydrous product of the resinification vessel was diluted 50-50 with furfuryl alcohol.
  • the formaldehyde level of this furfuryl alcohol-formaldehyde composition was about 8%
  • a series of wet sand mixes were prepared utilizing this composition and Juniata sand, each containing varying amounts of phosphoric acid catalyst and/ or other catalysts. Each mix in this series contained 20% boric acid based on weight of binder and 4% binder based on weight of mix. Cores were produced as in Example 6 employing various box temperatures and dwell times. The results are summarized in Table III.
  • Test specimens 1 /8" in diameter were prepared by blowing mix into a box heated to 400 F. and allowing dwell time of 30 seconds. Compressive strength of cured specimens was determined at 1500 F. and 2500 F. using a Dietert No. 785 Thermolab with a hooded post. Specimens were in a helium atmosphere using flow rate of 1 liter per minute at time of test. The results are tabulated in Table IV.
  • the preferred embodiment of this invention utilizes binders containing formaldehyde which is incorporated into highly advanced copolymers.
  • One practical advantage is the drastic improvement in the odor problem, both during mixing and/or mulling and blowing operations.
  • the following tests were conducted at elevated temperature (120 F.).
  • Each of the resins referred to in Table VII was prepared by a procedure similar to that described in Example 3. Twenty parts of boric acid was added per 100 parts of binder, and two parts binder was used per 100 parts of sand in each set of tests.
  • Furf'uryl alcohol-, furfuryl alcohol-formaldehyde-boric acid mixtures have. a room temperature life far beyond the needs of most foundries. Under room temperature conditions, mixtures such as these have proven entirely .satisfactory inthe method of this invention even after months of time lapsed between. the. time. they were mixed.
  • EXAMPLE 10 A furfuryl alcohol-formaldehyde resin was prepared in a manner similar to that of Example 1. A mixture containing 0.25 moles of formaldehyde (as 37% formalin) per mole of furfuryl alcohol was resinified using 0.08% oxalic acid as a catalyst until a 56,000 cps. viscosity (40 C.) was obtained. The final substantially anhydrous resin was diluted with furfuryl alcohol until viscosity was reduced to 180 cps. at 25 C. This required 0.847 pound of furfuryl alcohol per pound of resin.
  • test cores were prepared using the liquid fu-rfuryl alcohol-formaldehyde composition of Example 10, 5% phosphoric acid, and 20% boric acid based on the weight of the binder, and produced in accordance with the method of this invention, utilizing a 60-second dwell in the foundry core box at 450 F., followed by about Five additional sets of test cores were prepared using various commercial binders and prior art methods, including the traditional cereal oil, and a phenolic binder used in the dry dump shell mold method. These five test samples were prepared essentially in accord. with the manufacturers recommendations and accepted art procedures. The binders are identified in the Sample. Identity tabulation of Table VIII, in which the percent binder refers to. the percent of binder based on the weight of sand mix.
  • the percent catalyst in Table VIII refers to the percent of catalyst based on. the weight of binder pl-us catalyst.
  • Catalyst (A) is an aqueous solution containing '1- part ammonium chloride and 40 parts urea per 100 parts solution.
  • Catalyst (B) is an aqueous solution containing 2.5 parts ammonium chloride and 40 parts urea per 100 parts solution.
  • Catalyst (C) is an aqueous solution containing 4.0 parts ammonium chloride and 40 parts urea per 100 parts solution.
  • Catalyst (D) is aqueous phosphoric acid.
  • the Ignition Loss reported in Table VIII represents the percent of initial cured sample weight which is lost in two hours at 800 C. (air atmosphere).
  • the rate of gas evolution at 2500 F. of the six sets of cured cores was determined using a modified Dietert gas determinator.
  • volume, etc. are made at predetermined time intervals.
  • the Gas Evolved volumes reported in Table VIII are an indication of the rate at which gas is evolved by the cured core or mold at pour temperature. The value reported is the number of milliliters of gas evolved by a IO-gram sample of the core or mold in the first twenty seconds after the sample and its container were plunged into a zone heated to 2500 F. (nitrogen atmosphere). These values are corrected for readings changes encounteredvwhen blanks are run in the same manner using only 10 grams of dry sand and the sample container. The results obtained are summarized in Table VIII below.
  • Cereal-oil binder 1.0% MO GUL (Corn Products Corporation) +1.25% Linseed Oil (Archer-D aniels-Midlan d) 2.
  • Urea-Formaldehyde binder 2.0% URAC 180 (American Cyanamid Corporation).
  • UrearFormaldehyde-Furiuryl Alcohol binder FURSET 2590 (2.0%) (The Quaker Oats Company).
  • Urea-Fonnaldehyde-Furfuryl Alcohol binder 2.00% FURSET 4090 (The Quaker Oats Company).
  • Example binder 2.00% binder based on the weight of sand mix.
  • the Comparison column in Table VIII relates the volume of gas evolved during the initial 20 seconds by the sample to that evolved during the same period by cores or molds produced by the method of this invention in accordance with Example 10. The dramatic decrease in rate of gas evolution from cores and molds produced in accordance with the method of this invention is evident from the above data. Castings produced utilizing the prior art cores and molds (first five listed in Table VIII) exhibit pinholin-g of various degrees of severity.
  • Nodular iron and steel castings manufactured from the cores and molds :produced by the process of this invention are substantially 100% free of pinholes as determined by X-ray examinations.
  • production rates previously unattainable can be achieved.
  • the quality of these cores and molds, in terms of surface soundness, handleability, cold and hot strengths, and shakeout, is most satisfactory. The invention is thus believed to constitute a significant and patentable advance in the art.
  • a method for the high-speed production of cores and molds suitable for production of substantially pinhole-free iron and steel castings comprising the following steps:
  • Y binder in an amount between about 0.5 and 6.0
  • said binder consisting essentially. of a boroncontaining component selected from the Binder contains group consisting of boron oxides, boron acids reflecting the various degrees of hydration of boron oxides, and lower oxy acids of boron, said boron-containing component being'present in an amount between 5 and 40% by weight based on the weight about 2 and 30% formaldehyde level, and (b) a liquid furfuryl alcohol-formaldehyde composition containing at least 15% furfuryl alcohol monomer and having between about 12 and about 30% formaldehyde level, said mixing continuing until said binder is substantially uniformly distributed on said foundry sand, thereby providing a hardenable, shapable foundry mix,
  • step 2 (2) applying the foundry mix provided by step 1 to a shaped, heated surface
  • said surface being at a temperature between 350 and 600 F.
  • the boron containing component is boricacid and said second component is a mixture of an acidcatalyst in an amount between 0.5 and 15% by weight based on the weight of said mixture, and aliquid furfuryl alcohol-formaldehyde composition in an amount between 99.5 and by weight based on the weight of said mixture, said composition containing at least 15 furfuryl alcohol monomer, and between about 2 and 30% formaldehyde level.
  • boric acid in an amount between 15 and 25% by weight based on the weight of the binder
  • composition comprising (a) furfuryl alcohol monomer in an amount between 30 and 60% by weight based on the weight of said mixture, and
  • composition having between 2 and 30% formaldehyde level.
  • a method for the high-speed production of cores suitable for use in production of substantially pinholefree iron and steel castings comprising the following steps:
  • binder in an amount between about 0.5 and 6.0
  • said binder consisting essentially of a boroncontaining component selected from the group consisting of boron oxides, boron acids reflecting the various degrees of hydration of boron oxides, and lower oxy acids of boron, said boron-containing component being present in an amount between and 40% by weight based on the weight of the binder, and a second component which is a member selected from the group consisting of (a) a mixture of an acid catalyst, in an amount between 0.5 and 15% by weight based on the weight of said mixture, and liquid furfuryl alcohol-formaldehyde composition in an amount between 99.5 and 85% by weight based on the weight of said mixture, said composition containing at least 15% furfuryl alcohol monomer, and having between about 2 and 30% formaldehyde level, and (b) a liquid furfuryl alcohol-formaldehyde composition containing at least 15% furfuryl alcohol monomer and having between about 12 and about 30% formaldehyde level,
  • step 2 blowing the foundry mix provided by step 1 onto a shaped, heated surface in a core box
  • said surface having a temperature between 350 F. and 600 F.
  • a method for the high-speed production of shell molds suitable for use in production of substantially pinhole-free iron and steel castings comprising the following steps:
  • binder in an amount between about 0.5 and 6.0
  • said binder consisting essentially of a boroncontaining component selected from the group consisting of boron oxides, boron acids reflecting the various degrees of hydration of boron oxides, and lower oxy acids of boron, said boron-containing component being present in an amount between 5 and 40% by weight based on the weight of the binder, and a second component which is a member selected from the group consisting of (a) a mixture of an acid catalyst, in an amount between 05 and 15% by weight based on the weight of said mixture, and liquid furfuryl alcohol-formaldehyde composition in an amount between 99.5 and by weight based on the weight of said mixture, said composition containing at least 15% furfuryl alcohol monomer, and having between about 2 and 30% formaldehyde level, and (b) a liquid furfuryl alcoholformalde hyde composition containing at least 15% furfuryl alcohol monomer and having between about 12 and about 30% formaldehyde level,
  • the sand-contacting surfaces of said patterns having a temperature between 350 F. and 600 F., (3) permitting the foundry mix to dwell between said matched patterns for a period of time not less than about 10 seconds nor more than about 40 seconds sufficient to allow the foundry mix to become a selfsupporting handleable foundry shape, (4) separating the self-supporting foundry shape from said patterns, and (5 curing the self-supporting foundry shape at ambient room temperatures for at least 30 minutes.
  • the acid catalyst is phosphoric acid.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Mold Materials And Core Materials (AREA)
US256408A 1963-02-05 1963-02-05 Method for manufacturing foundry cores and molds Expired - Lifetime US3216075A (en)

Priority Applications (10)

Application Number Priority Date Filing Date Title
NL295300D NL295300A (ru) 1963-02-05
US256408A US3216075A (en) 1963-02-05 1963-02-05 Method for manufacturing foundry cores and molds
GB29484/63A GB1000671A (en) 1963-02-05 1963-07-25 Process for making cores and moulds
BR151234/63A BR6351234D0 (pt) 1963-02-05 1963-07-29 Processos para confeccao de machos e moldes de fundicao
CH943063A CH458637A (de) 1963-02-05 1963-07-29 Verfahren zur Schnellherstellung von Kernen und Formen
AT610263A AT251778B (de) 1963-02-05 1963-07-30 Verfahren zur Schnellherstellung von Kernen und Formen
LU45330D LU45330A1 (ru) 1963-02-05 1964-01-31
FR962433A FR1388184A (fr) 1963-02-05 1964-02-03 Procédé de fabrication de noyaux et de moules
ES296046A ES296046A1 (es) 1963-02-05 1964-02-04 Procedimiento para la producción extrarrápida de machos y modelos
BE643423D BE643423A (ru) 1963-02-05 1964-02-05

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US (1) US3216075A (ru)
AT (1) AT251778B (ru)
BE (1) BE643423A (ru)
BR (1) BR6351234D0 (ru)
CH (1) CH458637A (ru)
ES (1) ES296046A1 (ru)
GB (1) GB1000671A (ru)
LU (1) LU45330A1 (ru)
NL (1) NL295300A (ru)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3386016A (en) * 1965-08-02 1968-05-28 Sprague Electric Co Field effect transistor with an induced p-type channel by means of high work function metal or oxide
US3409582A (en) * 1964-04-22 1968-11-05 Quaker Oats Co Alkaline refractory mixtures containing formaldehyde-furylethylenealdehyde resins and gunning therewith
WO1995019235A1 (en) * 1994-01-12 1995-07-20 Ashland Inc. Heat cured foundry binders and their use
WO2012080454A1 (de) 2010-12-16 2012-06-21 Hüttenes-Albertus Chemische Werke GmbH EMISSIONSARMES KALTHÄRTENDES BINDEMITTEL FÜR DIE GIEßEREIINDUSTRIE
WO2023183192A1 (en) * 2022-03-22 2023-09-28 ASK Chemicals LLC Boric acid as a curing adjuvant in a warm box process

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2457753A1 (fr) * 1979-05-28 1980-12-26 Inventa Ag Procede pour la fabrication de moules
DE3411827A1 (de) * 1984-03-30 1985-10-10 Rütgerswerke AG, 6000 Frankfurt Haertbare formmassen und ihre verwendung
CN114082900A (zh) * 2021-11-25 2022-02-25 中车大连机车车辆有限公司 机车车钩钩舌覆膜砂砂芯制造工艺

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1039017A (fr) * 1950-07-04 1953-10-05 Terni Procédé de préparation d'agglomérants pour sables et terres de fonderie à base de résines synthétiques furfuriliques
US2874148A (en) * 1954-07-29 1959-02-17 Quaker Oats Co Resinification of furfuryl alcohol and formaldehyde at high hydrogen-ion concentrations
CA573760A (en) * 1959-04-07 E. Freeman Stephen Method and compositions for the production of foundry cores
US2999829A (en) * 1954-06-25 1961-09-12 Leo H Treat Aqueous shell molding composition comprising maleic acid, furfuryl alcohol, and urea
US3008205A (en) * 1958-09-19 1961-11-14 Gen Motors Corp Shell type molds and cores
US3024215A (en) * 1960-06-27 1962-03-06 Freeman Chemical Corp Foundry composition containing furfuryl alcohol polymer, foundry structure thereof, and method of making same
US3145438A (en) * 1958-09-18 1964-08-25 Archer Daniels Midland Co Gas cure of organic bonds for sand and abrasive granules

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA573760A (en) * 1959-04-07 E. Freeman Stephen Method and compositions for the production of foundry cores
FR1039017A (fr) * 1950-07-04 1953-10-05 Terni Procédé de préparation d'agglomérants pour sables et terres de fonderie à base de résines synthétiques furfuriliques
US2999829A (en) * 1954-06-25 1961-09-12 Leo H Treat Aqueous shell molding composition comprising maleic acid, furfuryl alcohol, and urea
US2874148A (en) * 1954-07-29 1959-02-17 Quaker Oats Co Resinification of furfuryl alcohol and formaldehyde at high hydrogen-ion concentrations
US3145438A (en) * 1958-09-18 1964-08-25 Archer Daniels Midland Co Gas cure of organic bonds for sand and abrasive granules
US3008205A (en) * 1958-09-19 1961-11-14 Gen Motors Corp Shell type molds and cores
US3024215A (en) * 1960-06-27 1962-03-06 Freeman Chemical Corp Foundry composition containing furfuryl alcohol polymer, foundry structure thereof, and method of making same

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3409582A (en) * 1964-04-22 1968-11-05 Quaker Oats Co Alkaline refractory mixtures containing formaldehyde-furylethylenealdehyde resins and gunning therewith
US3386016A (en) * 1965-08-02 1968-05-28 Sprague Electric Co Field effect transistor with an induced p-type channel by means of high work function metal or oxide
WO1995019235A1 (en) * 1994-01-12 1995-07-20 Ashland Inc. Heat cured foundry binders and their use
US5607986A (en) * 1994-01-12 1997-03-04 Ashland Inc. Heat cured foundry mixes and their use
WO2012080454A1 (de) 2010-12-16 2012-06-21 Hüttenes-Albertus Chemische Werke GmbH EMISSIONSARMES KALTHÄRTENDES BINDEMITTEL FÜR DIE GIEßEREIINDUSTRIE
CN103379971A (zh) * 2010-12-16 2013-10-30 胡坦斯·阿尔伯图斯化学厂有限公司 用于铸造工业的低发射冷固化粘合剂
DE202011110617U1 (de) 2010-12-16 2015-04-29 Hüttenes-Albertus Chemische Werke GmbH Emissionsarmes kalthärtendes Bindemittel für die Gießereiindustrie
CN103379971B (zh) * 2010-12-16 2015-09-30 胡坦斯·阿尔伯图斯化学厂有限公司 用于铸造工业的低发射冷固化粘合剂
US9993863B2 (en) 2010-12-16 2018-06-12 Huttenes-Albertus Chemische Werke Gmbh Low-emission cold-setting binder for the foundry industry
EP3495073A2 (de) 2010-12-16 2019-06-12 HÜTTENES-ALBERTUS Chemische Werke Gesellschaft mit beschränkter Haftung Mischung zur verwendung als bindemittel im no-bake-verfahren, reaktionsgemisch mit eine säure, verfahren zur herstellung der mischung, verfahren zum herstellen einer giessform oder eines kerns, verwendung der mischung sowie kit, der dieser mischung enthält
EP3495073A3 (de) * 2010-12-16 2019-07-10 HÜTTENES-ALBERTUS Chemische Werke Gesellschaft mit beschränkter Haftung Mischung zur verwendung als bindemittel im no-bake-verfahren, reaktionsgemisch mit einer säure, verfahren zur herstellung der mischung, verfahren zum herstellen einer giessform oder eines kerns, verwendung der mischung sowie kit, der dieser mischung enthält
WO2023183192A1 (en) * 2022-03-22 2023-09-28 ASK Chemicals LLC Boric acid as a curing adjuvant in a warm box process

Also Published As

Publication number Publication date
GB1000671A (en) 1965-08-11
LU45330A1 (ru) 1965-01-31
CH458637A (de) 1968-06-30
ES296046A1 (es) 1964-07-16
AT251778B (de) 1967-01-25
BE643423A (ru) 1964-08-05
BR6351234D0 (pt) 1973-06-26
NL295300A (ru)

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