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Publication numberUS3407864 A
Publication typeGrant
Publication dateOct 29, 1968
Filing dateJun 1, 1966
Priority dateJun 12, 1965
Also published asDE1483641A1, DE1483641B2, DE1483641C3
Publication numberUS 3407864 A, US 3407864A, US-A-3407864, US3407864 A, US3407864A
InventorsKurt Anderko, Manfred Stark, Rudolf Henle
Original AssigneeSchmidt Gmbh Karl
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Forming hollow cast articles
US 3407864 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

3,407,864 Patented Oct. 29, 1968 ice United States Patent 3 407 864 by enabling the gas to escape into the sintered salt core. Furthermore the r u tr tru tur lfects a essen- FORMING HOLLOW CAST ARTICLES 0 S Sm e S c e e 11 Kurt Anderko, Heflbrmm (Neckar), Rudolf Heme, tial decrease of time necessary for removing the core Neckarsulm, Wurttemberg, and Manfred Stark, from the castlng- ()dh im, Ge assignors t K -l S h idt 5 More particularly, sodium or potassium chloride mixed G.m.b.H., Neckarsulm, Wurttemberg, Germany, a with up to about of a sintering aid (the above re- P f Germany ferred to second constituent) is placed in an appropriately Flled J e 1966! 554,331 shaped mold and pressed into the shape of the mold for Claims priority,applgaltiog ygigamany,June 12,1965, about 1.5 to 2.5 minutes. The molded shape is then 4 Claimcs 1O dried, e.g. for about an hour at 200 C., and then sintered, e.g. for about /2 to 1 hour at about 700 C. The sintered This invention relates to the production of hollow core shap s are then cooled to about pffifel'ably castings. It more particularly refers to improvements in Without removing them from the sintering heating means. the production of cast metal articles having void spaces The thus produced sintered cores are available for use therein 15 in preparing hollow castings by suitably placing them in It is known to produce cast articles having voids therein the casting die and casting an appropriate material about by forming soluble cores and casting the desired article hem- It may in some cases be desirable to smooth out about the core or cores. After the article has been cast, the surfaces and particularly the edges of the sintered core. the cores are dissolved out thereby leaving the desirable This may be accomplished by sanding or grinding as the voids in the casting. One particularly desirable applica- 04186 y tion of this practice is in the manufacture of cylinder It has been found to be desirable in making use of the blocks for internal combustion engines. Channels for thus prepared sintered cores, to preheat them prior to cooling Water are suitably cast into the block by the insertion in the casting mold. Alternatively, it may be referred to technique of fugitive cores. practical to transfer the cores hot from the sintering step It has been the practice in the past to utilize water soluescribed directly to the casting mold. It has been found ble ma erials as the fugitive cores since they can be advisable to provide the sintered core at a temperature of dissolved and washed out most easily and economically. b ut 5-0 to 300 C. Where such core is to be used in Exemplary of the water soluble core materials which the production of hollow metal castings. Where the casthave been used are metal halide salts particularly sodium ings are to be made of materials having a lower melting and potassium chloride. These materials are quite inex- 3 Point, it y be desirable to Provide the sintered Cores at pensive as Well as easy to Work with and readily somewhat lower temperatures. recoverable. One specific example of a core made according to this It has been found that simple moldings and castings invention contained 95 weight percent: sodium chloride, produced in the prior art manner are excellent. However, 3 Weight percent borax, 1 weight percent magnesium oxide it has been found that in producing intricately shaped and 1 weight percent talc. Amixture of these materials in articles such as those containing sudden changes in crosshe r cit d proportions was made into a sintered core and section, the stresses on the core materials, both mechanillsfid to Produce a hollow cast metal PieCe. After the cal stresses and those induced by heating, are greatly casting had been cooled, the core was removed by simple increased. The soluble core materials of the prior art dissolution in Water. have been found to be somewhat lacking in these situa- The time required for the removal of the sintered salt tions. core was only /10 of that necessary for the removal of It is therefore an object of this invention to provide the salt cores of the known art. an improved core material for use in producing castings What is claimed is: containing voids. 1. In the method of forming a solid casting having at It is another object of thi invention t id an i nleast one predetermined void space therein which comproved process for the production of hollow cast articles. prises casting molten metal around at least one soluble Other and additional objects of this invention will be- Salt Core and then dissolving the Core material; the come apparent from a consideration of this entire specifi- P Ovetnent which comprises Providing as Said Core mate cation including the claims appended hereto, rial sintered salt comprising at least one soluble metal In accord with and f lfillin th j hi i halide salt and up to about 10 weight percent at least one tion includes the production of a hollow cast article by material Selected from the g p Consisting of bOIaX, casting such article about a fugitive core comprising at magnesium Oxide, and talcleast one soluble metal halide salt and up to about 10% The improved Process Claimed in Claim 1 wherein by weight of at least one second constituent selected from Said metal halide i8 Sodium Chloridethe group consisting of borax, magnesium oxide and talc. The improved Precess claimed in claim 1 wherein It is preferred to use water soluble cores. It is preferred, Said metal halide is Potassium Chlorideprincipally for economic reasons, to use sodium or potas- The improved Process Claimed in Claim 1 wherein i hl id as h metal h lid l said core contains borax, magnesium oxide, and talc.

Cores for use in this invention are suitably prepared by molding an appropriate mixture of metal halide and the References Cited second constituent into the shape of the void desired in UNITED STATES PATENTS the final casting. The shaped core is then dried and heated 1 523 5 9 25 Gibbons 0 3 9 to a sintering temperature by which treatment the core 554 97 9 1925 Alden 254-317 shape becomes dimensionally stable and strong enough 1,603,262 10/1926 Ald 106 .38,9 to withstand greater thermal and mechanical stresses than 2,420,851 5/ 1947 Zahn et a1. 164---35 was possible with prior art cores. 2,736,077 2/ 1956 Bartlett l64-36 The sintered salt cores according to the invention have 3,131,999 5/1964 Suzuki et a1. 164-16 also further advantageous properties. Owing to their 3,218,684 11/1965 Spink 164--79 porous sinter structure they are able e.g. to eliminate the V detrimental effect of the gas formation inevitably occur- SPENCER OVERHQLSEK p'lmary Emwnerring during the solidification of technical aluminum melts E, MAR, Assistant Examiner.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1523519 *Feb 12, 1924Jan 20, 1925Hartford Rubber Works CoCore or filler of fusible material for hollow vulcanizable articles
US1554697 *Jul 18, 1921Sep 22, 1925Milton AldenManufacture of hollow articles
US1603262 *Mar 6, 1926Oct 19, 1926Alden MiltonManufacture of hollow articles
US2420851 *Jul 8, 1943May 20, 1947Austenal Lab IncMethod of making patterns and use thereof
US2736077 *May 23, 1951Feb 28, 1956Thompson ProductsMethod of making shell mold
US3131999 *Mar 9, 1960May 5, 1964Sumitomo Metal IndFusible salt pattern composition and process of making molds
US3218684 *Aug 31, 1962Nov 23, 1965Dow Chemical CoProcess of making cellular metal structures
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3643728 *Jul 8, 1970Feb 22, 1972United Aircraft CorpProcess of casting nickel base alloys using water-soluble calcia cores
US3645491 *Jul 22, 1969Feb 29, 1972Aeroplane Motor Aluminum CastiSoluble metal casting cores comprising a water-soluble salt and a synthetic resin
US3701379 *Jul 6, 1971Oct 31, 1972United Aircraft CorpProcess of casting utilizing magnesium oxide cores
US3722574 *Jun 29, 1971Mar 27, 1973United Aircraft CorpProcess of making magnesium oxide cores
US3968828 *May 29, 1975Jul 13, 1976Ashland Oil, Inc.Method of casting non-ferrous alloys
US4134777 *Oct 6, 1977Jan 16, 1979General Electric CompanyMethod for rapid removal of cores made of Y2 O3 from directionally solidified eutectic and superalloy materials
US4925492 *Sep 21, 1987May 15, 1990The Interlake CorporationCeramic core for investment casting and method for preparation
US5232610 *Sep 15, 1989Aug 3, 1993Mclaughlin Timothy MMetallic pellets and a bonding agent
US5722038 *Feb 11, 1993Feb 24, 1998Mclaughlin; Timothy M.Mold element construction and related method
US5803151 *Apr 4, 1997Sep 8, 1998Alyn CorporationSoluble core method of manufacturing metal cast products
US5853825 *May 8, 1996Dec 29, 1998Parsons; Donald HomerFree form nugget and method of casting
US5921312 *Sep 18, 1997Jul 13, 1999Alyn CorporationSoluble core for casting
US6035923 *Aug 28, 1996Mar 14, 2000Mazda Motor CorporationMethod of and apparatus for producing light alloy composite member
WO1997035678A2 *Mar 10, 1997Oct 2, 1997Int Center For Paton InstChannel fabrication in metal objects
WO2013058152A1 *Oct 10, 2012Apr 25, 2013Suzuki Motor CorporationCasting core, method for producing same, and method for casting using said core
U.S. Classification164/522, 164/132, 106/38.9, 65/23, 164/246, 164/36, 264/221
International ClassificationB22C9/10
Cooperative ClassificationB22C9/105
European ClassificationB22C9/10C