US3413251A - Materials for the manufacture of foundry molds and cores - Google Patents

Materials for the manufacture of foundry molds and cores Download PDF

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US3413251A
US3413251A US392190A US39219064A US3413251A US 3413251 A US3413251 A US 3413251A US 392190 A US392190 A US 392190A US 39219064 A US39219064 A US 39219064A US 3413251 A US3413251 A US 3413251A
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cores
mixture
molds
parts
materials
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Thamlitz Heinz
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Huttenes Gebr KG
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    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C11/00—Shielding structurally associated with the reactor
    • G21C11/08—Thermal shields; Thermal linings, i.e. for dissipating heat from gamma radiation which would otherwise heat an outer biological shield ; Thermal insulation
    • G21C11/088—Thermal shields; Thermal linings, i.e. for dissipating heat from gamma radiation which would otherwise heat an outer biological shield ; Thermal insulation consisting of a stagnant or a circulating fluid
    • 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
    • B22C1/02—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by additives for special purposes, e.g. indicators, breakdown additives
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/30—Nuclear fission reactors

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  • ABSTRACT OF THE DISCLOSURE comprises adding to a mixture of wet foundry sand and hydrophilic binder of thermosetting synthetic resin such as furan resin a small amount of hydrophibic substance such as tall oil distillation residues, situmes, and fat acid pitches.
  • This invention relates to methods and materials for the manufacture of foundry molds and cores and particularly to a method and material for manufacturing foundry molds and cores with hydrophilic binders which are unaffected by moisture.
  • Cores and molds of both these types in the hardened condition are generally of satisfactory strength but are often very sensitive to moisture. This is a serious disadvantage because it is usually desired to produce a cast product from such molds which has a smooth, clean surface.
  • it is conventional to wash the surface of the mold or core with an aqueous suspension or slime of an inorganic or organic material such as quartz sand, zirconium sand flour, clay, graphite coal dust or the like material with small amounts of a water soluble binder.
  • This coating or wash may be applied by dipping the cores into the aqueous mixture, or by spraying or painting the aqueous mixture onto the surfaces of the cores and molds.
  • the washed cores or molds are then dried in order to remove the water, generally in a furnace. It has been found that this practice of washing the mold or core substantially reduces the strength of a mold or core of the hydrophilic type.
  • the present invention overcomes this problem of reduction in strength by moisture effect on molds and cores produced from wet sand mixtures with hydrophilic binding agents. According to the present invention, this improvement is attained by the addition of a small amount of hydrophobic or water repellent agent into the sand-hydrophilic binder admixture. This improvement is attained by adding 0.01% to 2% of a hydrophobic or water repellent agent to the sand and binder mixture or about 1% to 10% of such hydrophobic agent to the hydrophilic binder.
  • the invention is based upon the unexpected and surprising discovery that wet sand mixtures with a hydrophilic binder such as the hydrophilic resin binders may be insensitive to moisture by the addition of small amounts of hydrophobic materials so that moulds and cores made therefrom after being baked retain their strength even after washing with aqueous washes or slimes.
  • hydrophobic substances which have been found to be advantageous in the practice of this invention are solutions of bitumes, bituminous materials, the distillation residues of fatty acids, the distillation residues of tall oil and similar materials.
  • compositions of the samples In addition to the compositions of the samples the results of the two tensile strength tests just referred to are given below. All compositions are given in parts by weight.
  • Mixture 1a 100 parts of quartz sand. 0.6 part of orthophosphoric acid (acting as catalyst). 2.0 parts of furan resin (acting as hydrophilic binder). 0.3 part of a distillation residue of tall oil (acting as hydrophobic substance).
  • Mixture 2 100 parts of quartz sand. 0.4 part of aqueous solution of NH Cl. 2.0 parts of furan resin (acting as hydrophilic binder).
  • Tensile strengths 995 p.s.i. before immersion. 500 p.s.i. after immersion.
  • Mixture 2a 100 parts of quartz sand. 0.4 part of aqueous solution of NH Cl. 2.0 parts of furan resin (acting as hydrophilic binder). 0.02 part of a distillation residue of tall oil (acting as hydrophobic substance).
  • quartz sand 0.4 part of aqueous solution of NH Cl 2.0 parts of a mixture containing approximately percent by weight of furan resin (acting as hydrophilic binder) and 5 percent by weight of a distillation residue of tall oil (acting as hydrophobic substance).
  • a preferred embodiment of the invention comprises a hydrophilic mixture of sand, such as Ottawa sand, with a hydrophilic resin binder, such as ureaformaldehyde furfuryl alcohol, to which is added 0.01% to 0.2% of sulphate pitch dissolved in petroleum or test benzene.
  • a hydrophilic resin binder such as ureaformaldehyde furfuryl alcohol
  • a foundry core and mold mixture essentially com prising wet foundry sand, furan resin as hydrophilic binder, and about 0.01% to about 2% of hydrophobic substance selected from the group consisting of solutions of bitumes, bituminous materials, distillation residues of vegetable and animal oils, distillation residues of fatty acids and distillation residues of tall oil.
  • Mixture according to claim 1 essentially comprising 100 parts of quartz sand, 06 part of orthophosphoric acid, 2.0 parts of furan resin and 0.3 part of a distillation residue of tall oil.
  • Mixture according to claim 1 essentially comprising 100 parts of quartz sand, 0.4 part of aqueous solution of NH C1, 2.0 parts of furan resin and 0.02 part of a distillation residue of tall oil.
  • Mixture according to claim 1 essentially comprising 100 parts of quartz sand, 0.4 part of aqueous solution of NH CI and 2.0 parts of a mixture consisting of approximately by weight of furan resin and approximately 5% by weight of a distillation residue of tall oil.

Description

Nov. 26, 1968 H. THAMLITZ 3,413,251
MATERIALS FOR THE MANUFACTURE OF FOUNDRY MOLDS AND CORES Filed Aug. 26, 1964 TENS/LE STRENGTH, PSI
TIME, HOURS (MIXTURE 2 United States Patent "ice 3,413,251 MATERIALS FOR THE MANUFACTURE OF FOUNDRY MOLDS AND CORES Heinz Thamlitz, Kaarst, near Neuss, Germany, assignor to Gebr. Huttenes Kommanditgesellschaft, Dusseldorf- Heerdt, Germany Filed Aug. 26, 1964, Ser. No. 392,190 Claims priority, application Germany, Sept. 20, 1963, H 50,314 6 Claims. (Cl. 26024) ABSTRACT OF THE DISCLOSURE Method of producing mixtures suitable for the production of foundry molds and cores comprises adding to a mixture of wet foundry sand and hydrophilic binder of thermosetting synthetic resin such as furan resin a small amount of hydrophibic substance such as tall oil distillation residues, situmes, and fat acid pitches.
This invention relates to methods and materials for the manufacture of foundry molds and cores and particularly to a method and material for manufacturing foundry molds and cores with hydrophilic binders which are unaffected by moisture.
Methods and materials for the manufacture of foundry cores and molds are generally known. They fall basically into two types: (1) those that use hydrophobic binders and (2) those that use hydrophilic binders.
Cores and molds of both these types in the hardened condition are generally of satisfactory strength but are often very sensitive to moisture. This is a serious disadvantage because it is usually desired to produce a cast product from such molds which has a smooth, clean surface. In order to accomplish this, it is conventional to wash the surface of the mold or core with an aqueous suspension or slime of an inorganic or organic material such as quartz sand, zirconium sand flour, clay, graphite coal dust or the like material with small amounts of a water soluble binder. This coating or wash may be applied by dipping the cores into the aqueous mixture, or by spraying or painting the aqueous mixture onto the surfaces of the cores and molds. The washed cores or molds are then dried in order to remove the water, generally in a furnace. It has been found that this practice of washing the mold or core substantially reduces the strength of a mold or core of the hydrophilic type.
The present invention overcomes this problem of reduction in strength by moisture effect on molds and cores produced from wet sand mixtures with hydrophilic binding agents. According to the present invention, this improvement is attained by the addition of a small amount of hydrophobic or water repellent agent into the sand-hydrophilic binder admixture. This improvement is attained by adding 0.01% to 2% of a hydrophobic or water repellent agent to the sand and binder mixture or about 1% to 10% of such hydrophobic agent to the hydrophilic binder.
The invention is based upon the unexpected and surprising discovery that wet sand mixtures with a hydrophilic binder such as the hydrophilic resin binders may be insensitive to moisture by the addition of small amounts of hydrophobic materials so that moulds and cores made therefrom after being baked retain their strength even after washing with aqueous washes or slimes. Among the hydrophobic substances which have been found to be advantageous in the practice of this invention are solutions of bitumes, bituminous materials, the distillation residues of fatty acids, the distillation residues of tall oil and similar materials.
The following examples are to show the influence of 3,413,251 Patented Nov. 26, 1968 hydrophobic substances upon the sensitivity to water of cores and molds which before had hydrophilic properties. Various mixtures whose compositions are given below were subjected to the same type of test. All the mixtures were prepared in a pug mill and samples made of each mixture. Each sample was then stored for 24 hours, or hardened, as will be indicated below, and its tensile strength determined subsequently. Thereafter, a further sample of the same mixture, after storing it for 24 hours, or hardening, was immersed in water for 30 seconds and after superficial drying by allowing the water to drip off for 10 seconds also subjected to a tensile strength test.
In addition to the compositions of the samples the results of the two tensile strength tests just referred to are given below. All compositions are given in parts by weight.
Mixture 1 Composition:
100 parts of quartz sand 0.6 part of orthophosphoric acid (acting as catalyst).
2.0 parts of furan resin (acting as hydrophilic binder).
Tensile strengths:
710 p.s.i. before immersion.
210 p.s.i. after immersion.
Mixture 1a Composition: 100 parts of quartz sand. 0.6 part of orthophosphoric acid (acting as catalyst). 2.0 parts of furan resin (acting as hydrophilic binder). 0.3 part of a distillation residue of tall oil (acting as hydrophobic substance).
Tensile strengths:
850 p.s.i. before immersion. 570 p.s.i. after immersion.
The samples made of the above compositions, numbered 1 and 1a, were stored for 24 hours before the first tensile strength test was conducted. As distinguished therefrom, the samples made of the following mixtures were hardened in a heated pattern, and an aqueous solution of NH Cl was therefore added to the mixtures to act as hardening agent.
Mixture 2 Composition: 100 parts of quartz sand. 0.4 part of aqueous solution of NH Cl. 2.0 parts of furan resin (acting as hydrophilic binder).
Tensile strengths: 995 p.s.i. before immersion. 500 p.s.i. after immersion.
Mixture 2a Composition: 100 parts of quartz sand. 0.4 part of aqueous solution of NH Cl. 2.0 parts of furan resin (acting as hydrophilic binder). 0.02 part of a distillation residue of tall oil (acting as hydrophobic substance).
Tensile strengths:
995 p.s.i. before immersion. 855 p.s.i. after immersion.
Mixture 2b Composition:
100 parts of quartz sand 0.4 part of aqueous solution of NH Cl 2.0 parts of a mixture containing approximately percent by weight of furan resin (acting as hydrophilic binder) and 5 percent by weight of a distillation residue of tall oil (acting as hydrophobic substance).
Tensile strengths:
925 p.s.i. before immersion 780 p.s.i. after immersion.
A preferred embodiment of the invention comprises a hydrophilic mixture of sand, such as Ottawa sand, with a hydrophilic resin binder, such as ureaformaldehyde furfuryl alcohol, to which is added 0.01% to 0.2% of sulphate pitch dissolved in petroleum or test benzene. This will produce molds or cores which are completely resistant to reduction of strength when washed with aqueous Washes such as an aqueous suspension of zircon sand.
For the purpose of the invention, and particularly for eliminating the undesired influence of moisture on molds and cores, it has been found that in general satisfactory results are obtained if an amount of 0.2% of a hydrophobic material, and frequently even much less, is added to a mixture of sand and hydrophilic binder.
The effects obtained by adding hydrophobic substances to the mixtures also become evident if, as in the diagram shown in the drawing, the tensile strength is plotted vs. the time required to dry the coating of black wash which usually is applied to the surfaces of molds and cores. In the said diagram, Curve I shows the behavior of a sample made of the above-mentioned Mixture 1 and Curve II that of a sample made of the above-mentioned Mixture 2. It will be noted that Curve II shows a rather normal and continuous drop of the tensile strength, resulting from thermal effects, whereas, according to Curve II, the strength of the respective sample passes through a pronounced minimum value. Obviously, while the strength is at such low values the cores and molds are subject to deformation and may even break.
In the foregoing specification, there have been set out certain examples and preferred embodiments and practices of this invention. However, it will be understood that this invention may be otherwise embodied within the scope of the following claims.
What I claim is:
1. A foundry core and mold mixture essentially com prising wet foundry sand, furan resin as hydrophilic binder, and about 0.01% to about 2% of hydrophobic substance selected from the group consisting of solutions of bitumes, bituminous materials, distillation residues of vegetable and animal oils, distillation residues of fatty acids and distillation residues of tall oil.
2. Mixture according to claim 1, wherein the hydrophobic substance consists of 0.01 to 0.2% of sulfate pitch solution in petroleum.
3. Mixture according to claim 1, wherein the hydrophobic substance consists of 0.01 to 0.2% of sulfate pitch solution in test benzine.
4. Mixture according to claim 1, essentially comprising 100 parts of quartz sand, 06 part of orthophosphoric acid, 2.0 parts of furan resin and 0.3 part of a distillation residue of tall oil.
5. Mixture according to claim 1, essentially compris ing 100 parts of quartz sand, 0.4 part of aqueous solution of NH C1, 2.0 parts of furan resin and 0.02 part of a distillation residue of tall oil.
6. Mixture according to claim 1, essentially comprising 100 parts of quartz sand, 0.4 part of aqueous solution of NH CI and 2.0 parts of a mixture consisting of approximately by weight of furan resin and approximately 5% by weight of a distillation residue of tall oil.
References Cited UNITED STATES PATENTS 3,004,312 10/1961 Froberger 260-38 2,988,525 6/1961 Clem 26038 2,955,336 10/1960 Horn et a1 260-28 2,923,989 2/ 1960 Thomson 26037 2,892,227 6/ 1959 Operhall 26039 2,861,307 11/1958 Froberler 26028 2,657,113 10/1953 Barlow 26028.5 2,586,585 2/ 1952 Wallace 260-39 FOREIGN PATENTS 730,178 5/1955 Great Britain.
OTHER REFERENCES Varnish Constituents-Chatfield-Leonard-Hill Ltd., London, 1953, pages 619, 634.
DONALD E. CZAJA, Primary Examiner.
C. W. IVY, Assistant Examiner.
US392190A 1963-09-20 1964-08-26 Materials for the manufacture of foundry molds and cores Expired - Lifetime US3413251A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2199485A1 (en) * 1972-08-24 1974-04-12 Shell Int Research
FR2448399A1 (en) * 1979-01-12 1980-09-05 Proizv Ob BINDER FOR AIR-SOLIDABLE MOLDING SAND, PROCESS FOR PREPARING SAID BINDER AND AIR-SOLIDABLE MOLDING SAND CONTAINING SAID BINDER
CN107282870A (en) * 2017-07-11 2017-10-24 马鞍山市兴隆铸造有限公司 A kind of preparation method of high intensity furan resin-sand

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2586585A (en) * 1949-09-14 1952-02-19 Whitehead Bros Co Synthetic mold composition
US2657113A (en) * 1950-02-13 1953-10-27 Int Minerals & Chem Corp Foundry composition and method
GB730178A (en) * 1951-09-18 1955-05-18 Coneygre Foundry Ltd Improved sand cores and moulds for the casting of metals
US2861307A (en) * 1956-01-10 1958-11-25 Gen Motors Corp Shell molds
US2892227A (en) * 1956-01-11 1959-06-30 Derald H Ruttenberg Metal casting process and elements and compositions employed in same
US2923989A (en) * 1960-02-09 Self-lubricating shell molds
US2955336A (en) * 1956-08-06 1960-10-11 Ford Motor Co Shell molding sand and the process of making and using the same
US2988525A (en) * 1957-07-09 1961-06-13 American Colloid Co Foundry mold composition
US3004312A (en) * 1953-06-25 1961-10-17 Gen Motors Corp Process of shell molding

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2923989A (en) * 1960-02-09 Self-lubricating shell molds
US2586585A (en) * 1949-09-14 1952-02-19 Whitehead Bros Co Synthetic mold composition
US2657113A (en) * 1950-02-13 1953-10-27 Int Minerals & Chem Corp Foundry composition and method
GB730178A (en) * 1951-09-18 1955-05-18 Coneygre Foundry Ltd Improved sand cores and moulds for the casting of metals
US3004312A (en) * 1953-06-25 1961-10-17 Gen Motors Corp Process of shell molding
US2861307A (en) * 1956-01-10 1958-11-25 Gen Motors Corp Shell molds
US2892227A (en) * 1956-01-11 1959-06-30 Derald H Ruttenberg Metal casting process and elements and compositions employed in same
US2955336A (en) * 1956-08-06 1960-10-11 Ford Motor Co Shell molding sand and the process of making and using the same
US2988525A (en) * 1957-07-09 1961-06-13 American Colloid Co Foundry mold composition

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2199485A1 (en) * 1972-08-24 1974-04-12 Shell Int Research
FR2448399A1 (en) * 1979-01-12 1980-09-05 Proizv Ob BINDER FOR AIR-SOLIDABLE MOLDING SAND, PROCESS FOR PREPARING SAID BINDER AND AIR-SOLIDABLE MOLDING SAND CONTAINING SAID BINDER
CN107282870A (en) * 2017-07-11 2017-10-24 马鞍山市兴隆铸造有限公司 A kind of preparation method of high intensity furan resin-sand

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BE653227A (en) 1965-01-18
NL6410844A (en) 1965-03-22
DE1433960A1 (en) 1968-11-14

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