EP2307158A2 - Noyaux à base de sel et procédé de fabrication desdits noyaux - Google Patents

Noyaux à base de sel et procédé de fabrication desdits noyaux

Info

Publication number
EP2307158A2
EP2307158A2 EP09780844A EP09780844A EP2307158A2 EP 2307158 A2 EP2307158 A2 EP 2307158A2 EP 09780844 A EP09780844 A EP 09780844A EP 09780844 A EP09780844 A EP 09780844A EP 2307158 A2 EP2307158 A2 EP 2307158A2
Authority
EP
European Patent Office
Prior art keywords
water
soluble
soluble salt
salt cores
core
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.)
Withdrawn
Application number
EP09780844A
Other languages
German (de)
English (en)
Inventor
Dirk Thiemann
Gudrun Schiller
Dieter Käfer
Peter Stingl
Harald Hudler
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ceramtec GmbH
Original Assignee
Ceramtec GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Ceramtec GmbH filed Critical Ceramtec GmbH
Publication of EP2307158A2 publication Critical patent/EP2307158A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/10—Cores; Manufacture or installation of cores
    • B22C9/105—Salt cores

Definitions

  • the invention relates to cores and a method for producing cores from salt by core shooting for use as a cavity placeholder in the production of metallic castings, preferably via the die casting technology, which dissolve completely without leaving solid residues in a solvent and therefore completely and easily from the Have workpieces removed.
  • Nuclei which are used in the casting of metal workpieces in the molds to keep the cavities provided in the workpieces when filling the molds with the melt, are subject to significantly higher requirements than, for example, sand casting or low-pressure chill casting.
  • the cores must be easy to produce, dimensionally stable and contour-accurate, and the materials used for their production and the solvent dissolving them should not affect the casting quality, the environment or cause any health hazards.
  • the surface of the cores must be particularly smooth and contour-accurate and the cores must dissolve completely in a suitable solvent and can be easily removed without leaving solid residue from the cavities of the workpieces .
  • Residues of cores containing non-dissolvable components such as quartz sand can cause damage to surfaces to be refined or cause the failure of an aggregate, for example, when core residues lead to blockage of an injector in the common rail system of a diesel engine.
  • Object of the present invention is to produce cores of salt, which have the necessary strength during die casting of the workpieces and can be easily and completely removed from the workpieces.
  • salt cores according to the so-called core shooting method, also called shot salt cores, which withstand the extreme stresses which occur, for example, in die-cast aluminum. That is, the cores must on the one hand have a high strength and on the other hand can easily be dissolved out of the casting after casting.
  • sand cores can be prepared with water glass as a binder, which have a maximum strength of 500 N / cm 2 . Significantly higher values are achieved in the cores according to the invention, and yet the cores can be easily removed after casting without residue.
  • the cores according to the invention consist of a salt, the binder and optionally fillers, additives and catalysts can be mixed. These cores are intended for workpieces cast using nonferrous metals, such as aluminum, brass or copper, by the die casting process.
  • the cores according to the invention are composed of substances which dissolve completely in water as a preferred solvent for reasons of environmental protection and can thus be removed without residue from the cavities of the workpieces.
  • the cores according to the invention have the advantage that they are composed of substances which, when handled properly, do not show any gas-releasing reactions which pollute the environment, neither during their preparation nor during the casting process.
  • the quality of the castings is improved by avoiding casting defects such as blowholes, gas pores or the like due to the formation of corrosive gases.
  • the substances can be recovered by suitable processes from the liquid phase, for example the salt by spray drying or evaporation.
  • All compositions of the core materials according to the invention can be processed in conventional core shooters by core shooting as a shaping process.
  • the complexity of the geometry of the cores determines the core shooting parameters as well as the design and design of the tool for making the cores and shooting head of the core shooter.
  • the core shooting allows the production of geometrically very complicated cores built with great contour accuracy on the surface and homogeneous structure with uniform density and strength.
  • Suitable materials for the cores according to the invention are the water-soluble salts of alkali and alkaline earth elements such as sodium chloride, potassium chloride and magnesium chloride, the water-soluble sulfates and nitrates of alkali and alkaline earth elements such as potassium sulfate in particular, magnesium sulfate, and water-soluble ammonium salts such as ammonium sulfate.
  • alkali and alkaline earth elements such as sodium chloride, potassium chloride and magnesium chloride
  • the water-soluble sulfates and nitrates of alkali and alkaline earth elements such as potassium sulfate in particular, magnesium sulfate
  • water-soluble ammonium salts such as ammonium sulfate.
  • all easily soluble salts are suitable whose decomposition or melting point is above the temperature of the liquid molten metal.
  • the core materials can be easily and simply divided into the desired grain sizes or grain classes.
  • the chosen particle size distribution influences in particular the surface properties of the cores. The smaller the grain size, the smoother the surface.
  • the highest possible degree of filling is sought, which can be achieved by mixing different salts and optionally the additional substances with different distribution curves, for example by a bi- or trimodal grain distribution of the mixture.
  • grain sizes in the range of 0.01 mm to 2 mm are selected, depending on the material, desired surface quality and contour accuracy of the workpiece to be cast.
  • Water-soluble fillers may optionally replace part of the salt, up to 30% by volume, so as not to adversely affect the density and strength.
  • the grain size of the filler is suitably adjusted to the grain size or the particle size distribution of the salt.
  • a suitable binder or a suitable binder system is added to the salt before the core shooting.
  • All binders are possible which, after the curing process, are completely water-soluble, which well wet the salt and optionally the fillers, the mixture of these substances being malleable into cores by means of core shooting.
  • Silicate binders are generally suitable if they are water-soluble. It is also possible to use the water-soluble alkali metal and ammonium phosphates or binders of monoaluminum phosphate. Binders of soluble water glass are preferred.
  • the amount added depends on the water glass module, 1 to 5, and is dependent on Wetting behavior, between 0.5 wt .-% and 15 wt .-%, preferably 5 wt .-% to 8 wt .-%.
  • Wetting behavior between 0.5 wt .-% and 15 wt .-%, preferably 5 wt .-% to 8 wt .-%.
  • the properties of a mixture of salt, optionally filler and binder or binder system can be influenced by the targeted addition of additives. It is also a prerequisite here that these additives or the reaction products of these additives are completely removable from the cavity of a workpiece completely and without residue by dissolution in water, and that during casting no gasses adversely affecting the casting process are released, which can lead to casting defects.
  • these additives may include: wetting agents, additives which influence the consistency of the mixture, lubricants, deagglomeration additives, gelling agents, additives which alter the thermophysical properties of the core, for example the thermal conductivity, additives which prevent the metal from sticking to the cores Additives, which lead to a better homogenization and miscibility, additives, which increase the storability, additives, which prevent a premature hardening, additives, which prevent a smoke and condensate formation during the casting as well as additives, which lead to the acceleration of the hardening. These additives are known to those skilled in the art of making conventional cores. Their added quantity depends on the type and composition of the core material.
  • the gas influencing the core material preferably CO2 or air, in particular for hardening and drying of the cores, can be blown into the still closed form after firing.
  • the pressure may be lower than when shooting the cores and be up to about 5 bar.
  • a thermal aftertreatment of the cores at temperatures up to 500 ° C. is also possible.
  • a thermal treatment takes place already during shaping in the mold by heating it to a temperature matched to the core material.
  • the core material is composed of the salt and the binder and the additives such as fillers, additives and catalysts, if necessary, wherein the fillers and binders are inorganic. All substances can be homogeneously mixed with known mixing units. The amount of binder and additive additives to be added depends on the purpose of the cores and determines the surface quality as well as the density and strength of the cores.
  • the processing of the core materials is carried out separately from the core shooting process, where appropriate, suitable protective measures to prevent agglomeration and premature curing must be provided.
  • suitable protective measures to prevent agglomeration and premature curing must be provided.
  • treatment, transport and storage can also take place under protective gas.
  • Substances which alter the properties of the other materials of the core material are advantageously fed directly into the core shooter.
  • the mixing then takes place in the gas stream, which transports the other substances into the mold.
  • the core material is pressed between 1 bar and 10 bar, adjusted to the composition of the Core material or on the filling and flow of the mass injected into the mold.
  • the filling pressure is dependent on the particle size distribution or the grain size and grain shape. Fine-grained salts generally require higher shooting pressures.
  • composition and properties of a core have a significant impact on the quality of the die cast part. With reference to an embodiment, therefore, the most important properties are listed here.
  • the properties given refer to cores that are not coated with a size.
  • the core uses a core of NaCI with the following additional substances such as water glass binders and other additives such as release agents, setting retardants, wetting agents, etc.
  • the core was formed at a pressure of 6 bar on a core shooter. He was subjected to a thermal treatment of 1 min duration at 200 0 C for curing.
  • the present core is particularly suitable for use in die-cast aluminum. In aluminum die casting, liquid aluminum is pressed into the mold at a pressure of 10 MPa to 200 MPa. It flows into the mold at a speed of up to 120 m / sec. In order to withstand the forces occurring during casting, the core must be dimensionally stable. The mechanical properties of the material were determined on a sample measuring 180 mm in length, 22 mm in width and 22 mm in height. The flexural strength, measured according to VDG leaflet P73 (February 1996) is 1400 N / cm 2 .
  • the porosity also plays a decisive role.
  • the pore content is 30% in this embodiment.
  • salt cores based on sodium chloride have a density of 1.2 g / cm 3 to 1.8 g / cm 3 , determined by the buoyancy method. This corresponds to a porosity of 10% to 35%.
  • the flexural strength, measured according to VDG leaflet P73, is between 400 N / cm 2 and 1500 N / cm 2 .
  • the core After the die casting has cured, the core must be removed. It is important that the core completely and easily dissolves immediately and without solid residues.
  • the dissolution rate of the core material naturally depends on the core material and its pretreatment as well as the core size. For pure salt, it may differ from that for a composition with binder and fillers. Experiments with a die cast test part have shown that a core measuring 22 mm ⁇ 22 mm ⁇ 180 mm completely turns out with hot water within 1 minute to 2 minutes wash out the casting.
  • the present invention accordingly relates to:
  • the shaped cores have a density of 1.2 g / cm 3 to 1.8 g / cm 3 ;
  • water-soluble salts used are those whose decomposition or melting point is above the temperature of the liquid metal;
  • water-soluble salts used are chlorides of the alkali and alkaline earth elements, in particular sodium chloride, potassium chloride and / or magnesium chloride, water-soluble sulfates and nitrates of the alkali and alkaline earth elements, in particular potassium sulfate and / or magnesium sulfate, water-soluble ammonium salts, in particular ammonium sulfate or mixtures of these salts;
  • a portion of the core material contains a water-soluble filler, that the grain size of the filler is matched to the grain size of the core material and that the proportion of the filler in the core material up to 30
  • Vol .-% may be
  • binder water-soluble silicate compounds preferably water glasses, alkali phosphates, ammonium phosphates and / or monoaluminum phosphate or mixtures of these compounds are used;
  • binders between 0.5 wt .-%, and 15 wt .-% is;
  • binder is a water glass and the proportion of the binder, depending on the wetting behavior and water glass module between 0.5 wt .-% and 15 wt .-%;
  • water-soluble salt sodium chloride with a particle size between 0.01 mm and 2 mm and the binder is water glass;
  • binder water glass in a proportion of 0.5 wt .-% to 15 wt .-%, depending on the particle size distribution and matched to the water glass module, is included;
  • Wt .-% is and wherein the shaping in a core shooting machine with a shooting pressure of 6 bar at room temperature and is cured with hot air;
  • the density is 1.35 g / cm 3
  • the open porosity is 30%
  • the flexural strength is 1400 N / cm 2 ;
  • salt cores are heat treated after shaping at a temperature of 500 0 C.
  • the present invention therefore furthermore relates to:
  • Grain size distribution or the grain size and grain shape is formed to the salt core
  • salt cores are molded at pressures of 1 bar to 10 bar;
  • the components are mixed with particle sizes of different distribution curves, preferably by a bi- or trimodal grain distribution of the components in order to achieve a high degree of filling of the molds by the mixture (the core material);
  • water-soluble salts of the alkali and alkaline earth chlorides especially sodium chloride, potassium chloride and / or magnesium chloride, water-soluble sulfates and nitrates of alkali and alkaline earth elements, especially potassium sulfate and / or magnesium sulfate, and water-soluble ammonium salts, especially ammonium sulfate or mixtures of these salts which, if appropriate with the additional auxiliaries, are mixed homogeneously and shaped into a core;
  • the core materials are used with particle sizes in the range of 0.01 mm to 2 mm, depending on the material, the desired surface quality and contour accuracy of the metal to be cast workpiece;
  • the additional filler or additional fillers are added to the core material in a proportion of up to 30 vol .-% and the Grain size of the filler is matched to the grain size of the salt or salts;
  • binders are added with a proportion depending on the specific surface, the wetting behavior and the particle size distribution, and that these binders are preferably water-soluble silicate compounds, in particular water glasses, alkali phosphates, ammonium phosphates and monoaluminum phosphate;
  • nuclei are gassed after firing with gases tailored to the core material for hardening
  • cores are hardened after firing by a heat treatment adapted to the core material at temperatures up to 500 0 C.
  • the enumerated with o lists mean optional, preferably embodiments of the inventive method for producing water-soluble salt cores.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)
  • Mold Materials And Core Materials (AREA)
  • Catalysts (AREA)

Abstract

Les noyaux qui sont introduits dans le moule lors du moulage sous pression de pièces métalliques pour garder libres les cavités prévues dans les pièces lors du remplissage des moules avec le métal fondu sont soumis à de grandes exigences concernant leur stabilité de forme et leur capacité à être éliminés des cavités. Selon l'invention, la substance du noyau est donc totalement hydrosoluble et peut être éliminée des pièces avec de l'eau, sans laisser de résidus, et lesdits noyaux peuvent être fabriqués à partir de sels sous forme non liquide et d'additifs, selon le procédé du tir de noyaux avec compression, en fonction de la composition de la substance des noyaux et de la substance avec laquelle les noyaux sont enrobés.
EP09780844A 2008-07-18 2009-07-20 Noyaux à base de sel et procédé de fabrication desdits noyaux Withdrawn EP2307158A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102008040541 2008-07-18
PCT/EP2009/059317 WO2010007180A2 (fr) 2008-07-18 2009-07-20 Noyaux à base de sel et procédé de fabrication desdits noyaux

Publications (1)

Publication Number Publication Date
EP2307158A2 true EP2307158A2 (fr) 2011-04-13

Family

ID=41550765

Family Applications (1)

Application Number Title Priority Date Filing Date
EP09780844A Withdrawn EP2307158A2 (fr) 2008-07-18 2009-07-20 Noyaux à base de sel et procédé de fabrication desdits noyaux

Country Status (6)

Country Link
EP (1) EP2307158A2 (fr)
CN (1) CN102159342A (fr)
BR (1) BRPI0915997A2 (fr)
MX (1) MX2011000528A (fr)
RU (1) RU2551335C2 (fr)
WO (1) WO2010007180A2 (fr)

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Publication number Priority date Publication date Assignee Title
MX2012005213A (es) * 2009-11-06 2012-07-03 Emil Muller Gmbh Nucleos a base de sal, metodo para la produccion de los mismos y uso de los mismos.
DE102010051356B4 (de) * 2010-11-13 2019-02-21 Volkswagen Ag Verfahren zur Herstellung eines Einlegeteils für die Erzeugung eines Hohlraums in einem Gussbauteil sowie Einlegeteil
WO2013058152A1 (fr) * 2011-10-19 2013-04-25 スズキ株式会社 Noyau de coulée, son procédé de fabrication et procédé de moulage par coulée utilisant ledit noyau
DE102012203800B3 (de) * 2012-03-12 2013-05-29 Federal-Mogul Nürnberg GmbH Verfahren und Vorrichtung zum Herstellen eines Kolbens mit einem Kühlkanal, sowie danach hergestellter Kolben
DE102012204480A1 (de) * 2012-03-21 2013-09-26 Mahle International Gmbh Verfahren zur Herstellung eines gekühlten Ringträgers
CN102672138B (zh) * 2012-03-29 2014-10-22 山东华盛荣镁业科技有限公司 压铸模具和压铸方法
DE102012022331A1 (de) 2012-11-14 2013-05-16 Daimler Ag Salzkern und Herstellverfahren dafür
WO2015014711A1 (fr) 2013-07-24 2015-02-05 Emil Müller GmbH Noyaux de sel et procédés de fabrication additive pour réaliser des noyaux de sel
DE102013021197B3 (de) * 2013-12-17 2015-02-26 Daimler Ag Verfahren zum Herstellen eines Gießkerns sowie Gießkern
KR20180110930A (ko) * 2017-03-30 2018-10-11 현대자동차주식회사 중공형 솔트코어 및 이의 제조 방법
CN107262661A (zh) * 2017-05-23 2017-10-20 厦门建霖工业有限公司 一种耐高温高强度水溶性型芯及其制备方法
CN108838339A (zh) * 2018-08-03 2018-11-20 襄阳美利信科技有限责任公司 一种盐芯压铸的方法

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US3501320A (en) * 1967-11-20 1970-03-17 Gen Motors Corp Die casting core
SU768528A1 (ru) * 1978-07-03 1980-10-07 Предприятие П/Я А-3732 Смесь дл изготовлени водорастворимых стержней
US4446906A (en) * 1980-11-13 1984-05-08 Ford Motor Company Method of making a cast aluminum based engine block
JP2005066634A (ja) * 2003-08-22 2005-03-17 Toyota Motor Corp 水溶性中子バインダ、水溶性中子、及びその製造方法
DE10359547B3 (de) * 2003-12-17 2005-03-03 Emil Müller GmbH Wasserlösliche Salzkerne
WO2005058526A2 (fr) * 2003-12-17 2005-06-30 Ks Aluminium-Technologie Ag Noyau pouvant etre retire pour le moulage de metaux et procede de production dudit noyau
WO2006010449A2 (fr) * 2004-07-23 2006-02-02 Ceramtec Ag Innovative Ceramic Engineering Noyaux de fonderie en ceramique
US20090250587A1 (en) * 2005-09-30 2009-10-08 Kaefer Dieter Core and a Method for the Production Thereof

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Also Published As

Publication number Publication date
RU2551335C2 (ru) 2015-05-20
BRPI0915997A2 (pt) 2019-04-09
CN102159342A (zh) 2011-08-17
WO2010007180A3 (fr) 2010-06-17
MX2011000528A (es) 2011-10-14
WO2010007180A2 (fr) 2010-01-21
RU2011105861A (ru) 2012-08-27

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