EP2022578A1 - Salt core for casting - Google Patents
Salt core for casting Download PDFInfo
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- EP2022578A1 EP2022578A1 EP07743803A EP07743803A EP2022578A1 EP 2022578 A1 EP2022578 A1 EP 2022578A1 EP 07743803 A EP07743803 A EP 07743803A EP 07743803 A EP07743803 A EP 07743803A EP 2022578 A1 EP2022578 A1 EP 2022578A1
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- European Patent Office
- Prior art keywords
- ions
- expendable
- mol
- salt core
- salt
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- 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.)
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- 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 present invention relates to a water soluble expendable salt core for casting.
- casting such as aluminum high pressure die casting (HPDC) is a technique that injects a molten aluminum alloy into a metal mold at high speed under a high pressure to cast a near-net-shape structure.
- HPDC high pressure die casting
- an expendable core is used.
- the expendable core used in such a case must have a strength that can withstand a high pressure and high temperature because it may be subject to a large impact or impulse force fluctuation upon collision of a molten metal injected from the gate at high speed mold filling and because a high static compressive casting pressure is applied until solidification completion.
- the expendable core is removed from the cast product.
- the cast product has a complicated internal structure, if a generally used phenol resin bonded sand core is used as the expendable core, it is not easy to remove.
- a water soluble expendable salt core is available as the expendable core that can be removed by dissolution with, e.g., high-temperature water (reference 1: Japanese Patent Laid-Open No. 48-039696 , reference 2: Japanese Patent Laid-Open No. 50-136225 , and reference 3: Japanese Patent Laid-Open No. 52-010803 ).
- the expendable salt core as described above is formed by using a salt mixture of, e.g., sodium carbonate (Na 2 CO 3 ), potassium chloride (KCl), and sodium chloride (NaCl), melting these components, and molding.
- a salt mixture of, e.g., sodium carbonate (Na 2 CO 3 ), potassium chloride (KCl), and sodium chloride (NaCl) melting these components, and molding.
- an expendable fused salt core is formed by melting a salt and casting, however, the formation of a shrinkage cavity, micro-porosity, small heat crack, and the like would be caused in the salt core due to a change in volume such as solidification shrinkage occurring in the solidification process. It is therefore not easy to mold the expendable fused salt core conforming to the mold precisely. In this manner, with the prior art, an expendable fused salt core cannot be manufactured easily by casting using a molten salt.
- the present invention has been made to solve the above problems, and has as its object to facilitate manufacture of a water soluble expendable salt core for casting which is formed of a salt cast product obtained by molding after melting salts such as sodium and potassium and has a sufficient strength.
- An expendable salt core for casting according to the present invention is formed of a molten salt containing bromine ions, carbonate ions, and at least one of sodium ions and potassium ions.
- the molten salt is preferably formed of sodium ions, bromine ions, and carbonate ions.
- the molar ratio of carbonate ions in all the anions is preferably 30 mol%.
- the molar ratio of carbonate ions in all the anions is preferably 50 mol% to 80 mol%.
- the molten salt may be formed of potassium ions, bromine ions, and carbonate ions, and the molar ratio of carbonate ions in all the anions may be 30 mol%, or 50 mol% to 90 mol%.
- the molten salt may be formed of sodium ions, potassium ions, bromine ions, and carbonate ions.
- the melting temperature of the molten salt may fall within a range of 600°C to 680°C.
- the molar ratio of potassium ions in all the cations may be 50 mol% to 90 mol%, and the molar ratio of carbonate ions in all the anions may be 40 mol% to 80 mol%.
- a plurality of granular crystals are preferably formed in the parent phase in a dispersed state.
- the granular crystals are preferably formed of carbonate ions and at least one of sodium ions and potassium ions.
- the expendable salt core for casting is formed of a molten salt containing at least one of sodium ions and potassium ions, bromine ions, and carbonate ions.
- a water soluble expendable salt core for casting which is formed of a salt cast product obtained by melting and molding salts such as sodium and potassium can be manufactured easily to have a sufficient strength.
- Fig. 1 is a partially cutaway perspective view of a closed-deck type cylinder block which is cast using the expendable salt core for casting according to the present invention.
- reference numeral 1 denotes a closed-deck type cylinder block which is made of an aluminum alloy and cast using an expendable salt core 2 as an expendable salt core for casting according to the present invention.
- the cylinder block 1 is part of a water cooling 4-cycle 4-cylinder engine for a motorcycle which is molded into a predetermined shape by high pressure die casting (HPDC).
- the cylinder block 1 shown in Fig. 1 integrally has four cylinder bores 3, a cylinder body 4 having the cylinder bores 3, and an upper crank case 5 extending downward from the lower end of the cylinder body 4.
- a lower crank case (not shown) is attached to the lower end of the upper crank case 5.
- the upper crank case 5, together with the lower crank case, rotatably, axially supports a crank shaft (not shown) through a bearing.
- the cylinder body 4 is a so-called closed-deck-type cylinder body, and has a water jacket 6 which is formed in it using the expendable salt core 2.
- the water jacket 6 is formed to include a cooling water passage forming portion 7, cooling water inlet port 8, main cooling water passage 9, and communication passage 10.
- the cooling water passage forming portion 7 projects on one side of the cylinder body 4 and extends in the direction in which the cylinder bores 3 line up.
- the cooling water inlet port 8 is formed in the cooling water passage forming portion 7.
- the main cooling water passage 9 is formed to communicate with a cooling water distribution passage (not shown) formed in the cooling water passage forming portion 7 and cover all the cylinder bores 3.
- the communication passage 10 extends upward in Fig. 1 from the main cooling water passage 9 and opens to a mating surface 4a with respect to a cylinder head (not shown) at the upper end of the cylinder body 4.
- the water jacket 6 described above supplies cooling water flowing in from the cooling water inlet port 8 to the main cooling water passage 9 around the cylinder bores through the cooling water distribution passage, and guides the cooling water from the main cooling water passage 9 to a cooling water passage in the cylinder head (not shown) through the communication passage 10. Since the water jacket 6 is formed in this manner, the cylinder body 4 is covered with the ceiling wall (the wall that forms the mating surface 4a) of the cylinder body 4 except that the communication passage 10 of the water jacket 6 opens to the mating surface 4a at the upper end to which the cylinder head is connected. Hence, a closed-deck-type arrangement is formed.
- the expendable salt core 2 to form the water jacket 6 has a shape identical to that obtained by integrally connecting the respective portions of the water jacket 6.
- the cylinder body 4 is partly cut away to facilitate understanding of the shape of the expendable salt core 2 (the shape of the water jacket 6).
- the expendable salt core 2 is formed from a molten salt obtained by melting a salt mixture of a salt of bromine and at least one of sodium and potassium and a salt of carbonic acid and at least one of sodium and potassium.
- the expendable salt core 2 is formed into the shape of the water jacket 6 by, e.g., die casting.
- the components of the expendable salt core 2 will be described later in detail.
- the expendable salt core 2 can be formed by a casting method other than die casting, e.g., gravity casting.
- a mixture consisting of a plurality of salts (to be described later) is melted by heating to obtain a melt. Then, the melt is injected into an expendable salt core forming metal mold under a high pressure and solidified. After solidification, the obtained expendable salt core 2 is taken out from the mold.
- the passage forming portion 2a which forms the cooling water inlet port 8 and the cooling water distribution passage, an annular portion 2b which surrounds the four cylinder bores 3, and a plurality of projections 2c extending upward from the annular portion 2b are formed integrally.
- the projections 2c form the communication passage 10 of the water jacket 6.
- the expendable salt core 2 is supported at a predetermined position in the metal mold (not shown) by a core print (not shown) during casting, and is removed by dissolution with hot water or vapor after casting.
- the cylinder block 1 may be dipped in a dissolution tank (not shown) which contains dissolving liquid consisting of, e.g., hydrochloric acid and hot water.
- dissolving liquid consisting of, e.g., hydrochloric acid and hot water.
- the passage forming portion 2a and the projections 2c exposed to the mating surface 4a, of the expendable salt core 2 come into contact with the dissolving liquid and dissolve.
- the dissolved portions expand gradually until all the portions dissolve finally.
- hot water or vapor may be sprayed under a pressure from a hole.
- a core print may be inserted in portions where the projections 2c are to be formed.
- hydrochloric acid is used in the process of removing the expendable salt core 2 from the cylinder block 1 as a cast product, carbon dioxide gas foams.
- the foam provides a stirring function and promotes dissolution effectively.
- the expendable salt core 2 contains potassium carbonate and sodium carbonate, when it dissolves in water, the resultant water exhibits alkaline. This alkali state poses problems such as corrosion of the cylinder block 1 as an aluminum cast product. Regarding this problem, corrosion of the cylinder block can be prevented by adding hydrochloric acid to control pH to near 7.
- the expendable salt core 2 will be described.
- the expendable salt core 2 according to this embodiment is formed to at least contain at least one of potassium and sodium as cations and bromine as anions.
- the expendable salt core 2 is formed of a molten salt of bromine ions and at least one of sodium ions and potassium ions.
- the expendable salt core 2 is formed to also contain carbonic acid as anions.
- the expendable salt core 2 is formed by casting using a melt (molten salt) obtained by melting a salt mixture of sodium bromide and sodium carbonate.
- the expendable salt core 2 is formed by casting using a melt obtained by melting a salt mixture of potassium bromide and potassium carbonate.
- the expendable salt core 2 is formed by casting a melt obtained by melting a salt mixture of potassium bromide and sodium carbonate.
- the expendable salt core 2 is formed by casting a melt obtained by melting a salt mixture of sodium bromide and potassium carbonate.
- the expendable salt core 2 is formed by casting using a melt obtained by melting a salt mixture of at least three members of potassium bromide, sodium bromide, sodium carbonate, and potassium carbonate.
- the expendable salt core 2 is formed by casting using a melt obtained by melting a salt mixture of at least four members of potassium bromide, sodium bromide, sodium carbonate, and potassium carbonate.
- the expendable salt core 2 may contain other ions.
- the expendable salt core 2 main contain, in addition to bromine ions and carbonate ions as anions, other anions such as sulfuric acid ions, nitric acid ions, and chlorine ions.
- the expendable salt core 2 may be manufactured by die casting which performs casting using a solid-liquid coexisting melt such as a semi-solidified melt.
- a mixture (salt mixture) of the plurality of slats described above may be melted by heating to obtain a melt.
- the temperature of the melt may be decreased to set the melt in the semi-solidified (solid-liquid coexisting) state.
- the melt in the semi-solidified state may be injected into a metal mold for an expendable salt core under a high pressure and solidified. After solidification, the resultant product may be taken out from the metal mold, thus fabricating the expendable salt core 2.
- the expendable salt core 2 (expendable salt core for casting) according to the embodiment described above employs a bromide.
- a bromide When compared to an expendable salt core which is formed of chloride salts without using a bromide, the solidification shrinkage ratio is small, and shrinkage cavities do not form easily.
- a bromide has a lower latent heat of fusion than a chloride. With the expendable salt core 2 containing bromine, a melting energy can be reduced more when compared to an expendable salt core that does not contain bromine.
- a bromide has larger water solubility than a chloride.
- the expendable salt core 2 containing bromine dissolves more in an equivalent amount of water than the expendable salt core not containing bromine, so that it can be removed more quickly.
- a water soluble expendable salt core for casting formed of a salt cast product obtained by melting and molding salts such as sodium and potassium can be manufactured more easily.
- Tables 1 and 2 and Fig. 2 show a change in bending strength (measurement value) occurring when the anionic ratio of bromine ions to carbonate ions is changed in an expendable salt core manufactured by melting a salt mixture of sodium bromide and sodium carbonate. This refers to cases in which the molten salt to form the expendable salt core is formed of sodium ions, bromine ions, and carbonate ions.
- Table 1 shows the measurement results (maximum bending loads) of the bending strengths of the fabricated test pieces
- Table 2 shows the measurement results (maximum bending strengths) of the bending strengths of the fabricated test pieces. Tables 1 and 2 are identical except that representations of the measurement results are different.
- the concentration of each ion is measured according to the analysis method determined by the rules of ion chromatograph analysis of JIS standard K0127. As shown in Tables 1 and 2 and Fig. 2 , expendable salt cores in which a concentration YCO 3 2- of carbonate ions in all the cations is 30 mol% to 80 mol% exhibit high bending strengths exceeding a bending strength of 13.9 MPa. Particularly, expendable salt cores with YCO 3 2- of 50 mol% to 80 mol% exhibit higher bending strengths.
- Tables 3 and 4 and Fig. 3 show a change in bending strength (measurement value) occurring when the anion ratio of bromine ions to carbonate ions is changed in an expendable salt core manufactured by melting a salt mixture of potassium bromide and potassium carbonate. This refers to cases in which the molten salt to form the expendable salt core is formed of potassium ions, bromine ions, and carbonate ions.
- Table 3 shows the measurement results (maximum bending loads) of the bending strengths of the fabricated test pieces
- Table 4 shows the measurement results (maximum bending strengths) of the bending strengths of the fabricated test pieces. Tables 3 and 4 are identical except that representations of the measurement results are different.
- the concentration of each ion is measured according to the analysis method determined by the rules of ion chromatograph analysis of JIS standard K0127. As shown in Tables 3 and 4 and Fig. 3 , expendable salt cores in which the concentration YCO 3 2- of carbonate ions in all the cations is 60 mol% to 80 mol% exhibit high bending strengths exceeding a bending strength of 16.0 MPa.
- Tables 5, 6, and 7 show a change in bending strength (measurement value) occurring when the anion ratio of bromine ions to carbonate ions is changed in an expendable salt core manufactured by melting a salt mixture of sodium bromide, potassium bromide, potassium carbonate, and sodium carbonate. This refers to cases in which the molten salt to form the expendable salt core is formed of sodium ions, potassium ions, bromine ions, and carbonate ions.
- the following Tables 5, 6, and 7 show the measurement results (maximum bending strengths) of the bending strengths of the fabricated test pieces. The concentration of each ion is measured according to the analysis method determined by the rules of ion chromatograph analysis of JIS standard K0127, in the same manner as described above.
- Fig. 4 shows the relationship (phase diagram of Na-K-Br-CO 3 system) among the cation ratio of potassium ions, the anionic ratio of carbonate ions, and the melting temperature (liquidus temperature). This corresponds to the results of the above Tables 2, 4, 5, 6, and 7.
- the largest circles represent test pieces that exhibit an average bending strength exceeding 20 MPa.
- the second largest circles represent test pieces that exhibit an average bending strength of 15 MPa to 20 MPa.
- the third largest circles represent test pieces that exhibit an average bending strength of 10 MPa to 15 MPa.
- the smallest circles represent test pieces that exhibit an average bending strength of 0 MPa to 10 MPa.
- FIG. 4 also shows the liquidus temperature of NaBr when K + is 0 mol% and CO 3 2- is 0 mol%, the liquidus temperature of KBr when Na + is 0 mol% and CO 3 2- is 0 mol%, the liquidus temperature of Na 2 CO 3 when K + is 0 mol% and Br - is 0 mol%, and the liquidus temperature of K 2 CO 3 when Na + is 0 mol% and Br - is 0 mol%.
- thick lines represent eutectic lines.
- the melting temperature of the molten salt may be set to approximately 680°C at maximum.
- Fig. 5 is an SEM photograph of the solidification structure of an expendable salt core fabricated using a molten salt in which the concentration of potassium ions in all the cations is 50 mol% and the concentration of carbonate ions in all the anions is 70 mol%.
- the expendable salt core fabricated from the molten salt with this composition exhibits a bending strength of 20 MPa or more, as shown in Fig. 4 , thus providing a very high strength.
- a state is observed in which a plurality of granular crystals are evenly dispersed in the parent phase.
- the composition of the granular crystal portion observed in this manner was analyzed by an energy-dispersive X-ray spectroscopic analyzer.
- the concentration of potassium ions in all the cations was 32 mol%, and the concentration of carbonate ions in all the anions was 100 mol%.
- Fig. 6 is an SEM photograph of the solidification structure of an expendable salt core fabricated using a molten salt in which the concentration of potassium ions in all the cations is 60 mol% and the concentration of carbonate ions in all the anions is 70 mol%.
- the expendable salt core fabricated from the molten salt with this composition exhibits a bending strength of 15 MPa to 20 MPa, as shown in Fig. 4 , thus providing a high strength.
- this expendable salt core as shown in Fig. 6 , a state is observed in which a plurality of granular crystals are evenly dispersed in the parent phase.
- the composition of the granular crystal portion observed in this manner was analyzed by the energy-dispersive X-ray spectroscopic analyzer.
- the concentration of potassium ions in all the cations was 42 mol%, and the concentration of carbonate ions in all the anions was 100 mol%.
- Fig. 7 is an SEM photograph of the solidification structure of an expendable salt core fabricated using a molten salt in which the concentration of potassium ions in all the cations is 40 mol% and the concentration of carbonate ions in all the anions is 70 mol%.
- the expendable salt core fabricated from the molten salt with this composition exhibits a bending strength 0 MPa to 10 MPa, as shown in Fig. 4 , and does not provide a very high strength.
- this expendable salt core as shown in Fig. 7 , comparatively large dendrites are observed in the parent phase.
- the composition of the dendrite portion observed in this manner was analyzed by the energy-dispersive X-ray spectroscopic analyzer.
- the concentration of potassium ions in all the cations was 22 mol%, and the concentration of carbonate ions in all the anions was 100 mol%.
- a plurality of granular crystals need to be formed in the parent phase in a dispersed manner.
- the granular crystals and dendrites observed by the SEM described above are crystals (primary crystals) which are formed first in the cooling process of the molten salt, and have comparatively high melting temperatures. After primary crystals are formed, the portion containing eutectic mixtures having a comparatively low melting point solidifies to form parent phase portions around the primary crystals. If the primary crystals formed in the parent phase of eutectic mixtures in this manner are not large dendrites but smaller granular crystals, the obtained expendable salt core may provide a high strength.
- an expendable salt core formed of sodium ions, bromine ions, and carbonate ions and not containing potassium ions exhibits a high bending strength when the concentration of carbonate ions in all the anions is 30 mol% or falls between 50 mol% to 80 mol%.
- concentration of carbonate ions is 60 mol%, a state is also observed in the solidification structure of the expendable salt core in which a plurality of granular crystals are dispersed in the parent phase.
- NaBr is a fragile substance that causes cleavage fracture. With NaBr, only a low bending strength of less than 10 MPa is obtained, as described above. In contrast to this, when a carbonate is added to form the salt mixture, the solidified structure is formed of NaBr and Na 2 CO 3 , thus providing a higher bending strength.
- An expendable salt core having a high strength can be obtained not only by simply adding a carbonate, but also by selecting a composition in which a crystal structure having a comparatively high melting point is formed in the parent phase having a comparatively low melting point. As primary crystals are mixed in the parent phase, progress of cracks and the like may be interfered with, providing a high strength. If the primary crystals are large dendrites, cracks tend to progress. If the primary crystals are smaller granular crystals, a higher strength can be obtained as described above.
- a prismatic test piece with a predetermined size is fabricated. A load is applied to the test piece, and the bending load is obtained from the maximum load needed to break the test piece. Fabrication of the test piece will be described first.
- a rod-like test piece 901 as shown in Figs. 9A and 9B is formed using a predetermined metal mold.
- the employed metal mold is made of chrome molybdenum steel, e.g., SCM440H.
- Fig. 9A also shows riser portions 902 used when charging the metal mold with a melt. In measurement of the bending strength, the portions 902 are cut off.
- Fig. 9A is a side view
- Fig. 9B is a sectional view taken at the position b - b in Fig. 9A .
- the sizes indicated in Figs. 9A and 9B are design values of the metal mold.
- the test piece 901 is supported by two support portions 1001 arranged at the center of the test piece 901 at a gap of 50 mm from each other.
- two load portions 1002 at a gap of 10 mm from each other apply a load to the test piece 901.
- the load to be applied to the test piece 901 is gradually increased.
- the maximum load needed to break the test piece 901 was the bending load shown in Tables 1 and 3.
- the test piece 901 is formed by pouring the melt into the metal mold, it is difficult to form a test piece having a shape completely coinciding with the size true to the mold due to flow marks or shrinkage cavity.
- the present invention can be suitably used as a core in casting such as aluminum die casting.
Abstract
Description
- The present invention relates to a water soluble expendable salt core for casting.
- As is known well, casting such as aluminum high pressure die casting (HPDC) is a technique that injects a molten aluminum alloy into a metal mold at high speed under a high pressure to cast a near-net-shape structure. In this casting, when molding a cast product having a hollow structure, e.g., a water cooling water jacket in the closed-deck type cylinder block of an internal combustion engine, an expendable core is used. The expendable core used in such a case must have a strength that can withstand a high pressure and high temperature because it may be subject to a large impact or impulse force fluctuation upon collision of a molten metal injected from the gate at high speed mold filling and because a high static compressive casting pressure is applied until solidification completion. After casting, the expendable core is removed from the cast product. When the cast product has a complicated internal structure, if a generally used phenol resin bonded sand core is used as the expendable core, it is not easy to remove. In contrast to this, a water soluble expendable salt core is available as the expendable core that can be removed by dissolution with, e.g., high-temperature water (reference 1: Japanese Patent Laid-Open No.
48-039696 50-136225 52-010803 - The expendable salt core as described above is formed by using a salt mixture of, e.g., sodium carbonate (Na2CO3), potassium chloride (KCl), and sodium chloride (NaCl), melting these components, and molding. Hence, a high static compressive casting pressure resistance is obtained, and workability and stability of dimension accuracy in casting are improved.
- When an expendable fused salt core is formed by melting a salt and casting, however, the formation of a shrinkage cavity, micro-porosity, small heat crack, and the like would be caused in the salt core due to a change in volume such as solidification shrinkage occurring in the solidification process. It is therefore not easy to mold the expendable fused salt core conforming to the mold precisely. In this manner, with the prior art, an expendable fused salt core cannot be manufactured easily by casting using a molten salt.
- The present invention has been made to solve the above problems, and has as its object to facilitate manufacture of a water soluble expendable salt core for casting which is formed of a salt cast product obtained by molding after melting salts such as sodium and potassium and has a sufficient strength.
- An expendable salt core for casting according to the present invention is formed of a molten salt containing bromine ions, carbonate ions, and at least one of sodium ions and potassium ions. For example, the molten salt is preferably formed of sodium ions, bromine ions, and carbonate ions. In this case, in the molten salt, the molar ratio of carbonate ions in all the anions is preferably 30 mol%. Alternatively, in the molten salt, the molar ratio of carbonate ions in all the anions is preferably 50 mol% to 80 mol%.
- The molten salt may be formed of potassium ions, bromine ions, and carbonate ions, and the molar ratio of carbonate ions in all the anions may be 30 mol%, or 50 mol% to 90 mol%. Alternatively, the molten salt may be formed of sodium ions, potassium ions, bromine ions, and carbonate ions. The melting temperature of the molten salt may fall within a range of 600°C to 680°C. The molar ratio of potassium ions in all the cations may be 50 mol% to 90 mol%, and the molar ratio of carbonate ions in all the anions may be 40 mol% to 80 mol%.
- A plurality of granular crystals are preferably formed in the parent phase in a dispersed state. The granular crystals are preferably formed of carbonate ions and at least one of sodium ions and potassium ions.
- According to the present invention, the expendable salt core for casting is formed of a molten salt containing at least one of sodium ions and potassium ions, bromine ions, and carbonate ions. Hence, a water soluble expendable salt core for casting which is formed of a salt cast product obtained by melting and molding salts such as sodium and potassium can be manufactured easily to have a sufficient strength.
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Fig. 1 is a perspective view of a cylinder block which is cast using an expendable salt core for casting according to an embodiment of the present invention; -
Fig. 2 is a graph showing the bending strengths of bending test pieces; -
Fig. 3 is a graph showing the bending strengths of bending test pieces; -
Fig. 4 is a phase diagram showing the bending strengths of bending test pieces as well as the relationship among the cationic ratio of potassium ions vs. sodium ions, the anionic ratio of carbonate ions vs. bromine ions, and the liquidus temperature; -
Fig. 5 is an SEM photograph of a solidification structure in an expendable salt core; -
Fig. 6 is an SEM photograph of a solidification structure in an expendable salt core; -
Fig. 7 is an SEM photograph of a solidification structure in an expendable salt core; -
Fig. 8 is an SEM photograph of a solidification structure in an expendable salt core; -
Fig. 9A is a view showing the state of a test piece used for bending strength measurement; -
Fig. 9B is a partial sectional view showing the state of the test piece used for bending strength measurement; and -
Fig. 10 is a view for explaining bending strength measurement. - The embodiment of the present invention will be described hereinafter with reference to the drawings. First, how an expendable salt core for casting according to the embodiment of the present invention is used will be described with reference to
Fig. 1. Fig. 1 is a partially cutaway perspective view of a closed-deck type cylinder block which is cast using the expendable salt core for casting according to the present invention. Referring toFig. 1 , reference numeral 1 denotes a closed-deck type cylinder block which is made of an aluminum alloy and cast using anexpendable salt core 2 as an expendable salt core for casting according to the present invention. The cylinder block 1 is part of a water cooling 4-cycle 4-cylinder engine for a motorcycle which is molded into a predetermined shape by high pressure die casting (HPDC). - The cylinder block 1 shown in
Fig. 1 integrally has fourcylinder bores 3, acylinder body 4 having thecylinder bores 3, and anupper crank case 5 extending downward from the lower end of thecylinder body 4. A lower crank case (not shown) is attached to the lower end of theupper crank case 5. Theupper crank case 5, together with the lower crank case, rotatably, axially supports a crank shaft (not shown) through a bearing. - The
cylinder body 4 is a so-called closed-deck-type cylinder body, and has awater jacket 6 which is formed in it using theexpendable salt core 2. Thewater jacket 6 is formed to include a cooling waterpassage forming portion 7, coolingwater inlet port 8, main cooling water passage 9, andcommunication passage 10. The cooling waterpassage forming portion 7 projects on one side of thecylinder body 4 and extends in the direction in which the cylinder bores 3 line up. The coolingwater inlet port 8 is formed in the cooling waterpassage forming portion 7. The main cooling water passage 9 is formed to communicate with a cooling water distribution passage (not shown) formed in the cooling waterpassage forming portion 7 and cover all thecylinder bores 3. Thecommunication passage 10 extends upward inFig. 1 from the main cooling water passage 9 and opens to amating surface 4a with respect to a cylinder head (not shown) at the upper end of thecylinder body 4. - The
water jacket 6 described above supplies cooling water flowing in from the coolingwater inlet port 8 to the main cooling water passage 9 around the cylinder bores through the cooling water distribution passage, and guides the cooling water from the main cooling water passage 9 to a cooling water passage in the cylinder head (not shown) through thecommunication passage 10. Since thewater jacket 6 is formed in this manner, thecylinder body 4 is covered with the ceiling wall (the wall that forms themating surface 4a) of thecylinder body 4 except that thecommunication passage 10 of thewater jacket 6 opens to themating surface 4a at the upper end to which the cylinder head is connected. Hence, a closed-deck-type arrangement is formed. - The
expendable salt core 2 to form thewater jacket 6 has a shape identical to that obtained by integrally connecting the respective portions of thewater jacket 6. InFig. 1 , thecylinder body 4 is partly cut away to facilitate understanding of the shape of the expendable salt core 2 (the shape of the water jacket 6). - The
expendable salt core 2 according to this embodiment is formed from a molten salt obtained by melting a salt mixture of a salt of bromine and at least one of sodium and potassium and a salt of carbonic acid and at least one of sodium and potassium. Theexpendable salt core 2 is formed into the shape of thewater jacket 6 by, e.g., die casting. The components of theexpendable salt core 2 will be described later in detail. Note that theexpendable salt core 2 can be formed by a casting method other than die casting, e.g., gravity casting. In formation of theexpendable salt core 2 which employs die casting, first, a mixture consisting of a plurality of salts (to be described later) is melted by heating to obtain a melt. Then, the melt is injected into an expendable salt core forming metal mold under a high pressure and solidified. After solidification, the obtainedexpendable salt core 2 is taken out from the mold. - As shown in
Fig. 1 , in theexpendable salt core 2, thepassage forming portion 2a which forms the coolingwater inlet port 8 and the cooling water distribution passage, anannular portion 2b which surrounds the four cylinder bores 3, and a plurality ofprojections 2c extending upward from theannular portion 2b are formed integrally. Theprojections 2c form thecommunication passage 10 of thewater jacket 6. As is conventionally known, theexpendable salt core 2 is supported at a predetermined position in the metal mold (not shown) by a core print (not shown) during casting, and is removed by dissolution with hot water or vapor after casting. - To remove the
expendable salt core 2 after casting, the cylinder block 1 may be dipped in a dissolution tank (not shown) which contains dissolving liquid consisting of, e.g., hydrochloric acid and hot water. When dipping the cylinder block 1 in the dissolving liquid, thepassage forming portion 2a and theprojections 2c exposed to themating surface 4a, of theexpendable salt core 2 come into contact with the dissolving liquid and dissolve. The dissolved portions expand gradually until all the portions dissolve finally. In this core removing process, to promote dissolution of theexpendable salt core 2 left in thewater jacket 6, hot water or vapor may be sprayed under a pressure from a hole. In theexpendable salt core 2, in place of theprojections 2c, a core print may be inserted in portions where theprojections 2c are to be formed. - If hydrochloric acid is used in the process of removing the
expendable salt core 2 from the cylinder block 1 as a cast product, carbon dioxide gas foams. The foam provides a stirring function and promotes dissolution effectively. As theexpendable salt core 2 contains potassium carbonate and sodium carbonate, when it dissolves in water, the resultant water exhibits alkaline. This alkali state poses problems such as corrosion of the cylinder block 1 as an aluminum cast product. Regarding this problem, corrosion of the cylinder block can be prevented by adding hydrochloric acid to control pH to near 7. - The
expendable salt core 2 will be described. Theexpendable salt core 2 according to this embodiment is formed to at least contain at least one of potassium and sodium as cations and bromine as anions. In other words, theexpendable salt core 2 is formed of a molten salt of bromine ions and at least one of sodium ions and potassium ions. Theexpendable salt core 2 is formed to also contain carbonic acid as anions. - For example, the
expendable salt core 2 is formed by casting using a melt (molten salt) obtained by melting a salt mixture of sodium bromide and sodium carbonate. Alternatively, theexpendable salt core 2 is formed by casting using a melt obtained by melting a salt mixture of potassium bromide and potassium carbonate. Alternatively, theexpendable salt core 2 is formed by casting a melt obtained by melting a salt mixture of potassium bromide and sodium carbonate. Alternatively, theexpendable salt core 2 is formed by casting a melt obtained by melting a salt mixture of sodium bromide and potassium carbonate. Alternatively, theexpendable salt core 2 is formed by casting using a melt obtained by melting a salt mixture of at least three members of potassium bromide, sodium bromide, sodium carbonate, and potassium carbonate. Alternatively, theexpendable salt core 2 is formed by casting using a melt obtained by melting a salt mixture of at least four members of potassium bromide, sodium bromide, sodium carbonate, and potassium carbonate. - In addition to at least one of potassium ions and sodium ions as cations and bromine and carbonate ions as anions, the
expendable salt core 2 may contain other ions. For example, theexpendable salt core 2 main contain, in addition to bromine ions and carbonate ions as anions, other anions such as sulfuric acid ions, nitric acid ions, and chlorine ions. - In the above description, casting is performed using a melt obtained by melting a salt mixture. However, the present invention is not limited to this. For example, the
expendable salt core 2 may be manufactured by die casting which performs casting using a solid-liquid coexisting melt such as a semi-solidified melt. For example, a mixture (salt mixture) of the plurality of slats described above may be melted by heating to obtain a melt. Then, the temperature of the melt may be decreased to set the melt in the semi-solidified (solid-liquid coexisting) state. The melt in the semi-solidified state may be injected into a metal mold for an expendable salt core under a high pressure and solidified. After solidification, the resultant product may be taken out from the metal mold, thus fabricating theexpendable salt core 2. - The expendable salt core 2 (expendable salt core for casting) according to the embodiment described above employs a bromide. When compared to an expendable salt core which is formed of chloride salts without using a bromide, the solidification shrinkage ratio is small, and shrinkage cavities do not form easily. A bromide has a lower latent heat of fusion than a chloride. With the
expendable salt core 2 containing bromine, a melting energy can be reduced more when compared to an expendable salt core that does not contain bromine. A bromide has larger water solubility than a chloride. Hence, theexpendable salt core 2 containing bromine dissolves more in an equivalent amount of water than the expendable salt core not containing bromine, so that it can be removed more quickly. In this manner, with theexpendable salt core 2 according to this embodiment, a water soluble expendable salt core for casting formed of a salt cast product obtained by melting and molding salts such as sodium and potassium can be manufactured more easily. - Tables 1 and 2 and
Fig. 2 show a change in bending strength (measurement value) occurring when the anionic ratio of bromine ions to carbonate ions is changed in an expendable salt core manufactured by melting a salt mixture of sodium bromide and sodium carbonate. This refers to cases in which the molten salt to form the expendable salt core is formed of sodium ions, bromine ions, and carbonate ions. Table 1 shows the measurement results (maximum bending loads) of the bending strengths of the fabricated test pieces, and Table 2 shows the measurement results (maximum bending strengths) of the bending strengths of the fabricated test pieces. Tables 1 and 2 are identical except that representations of the measurement results are different. The concentration of each ion is measured according to the analysis method determined by the rules of ion chromatograph analysis of JIS standard K0127. As shown in Tables 1 and 2 andFig. 2 , expendable salt cores in which a concentration YCO3 2- of carbonate ions in all the cations is 30 mol% to 80 mol% exhibit high bending strengths exceeding a bending strength of 13.9 MPa. Particularly, expendable salt cores with YCO3 2- of 50 mol% to 80 mol% exhibit higher bending strengths. -
Table 1 Sample Number Cation Ratio mol% Anion Ratio mol% Liquidus Temperature °C Molding Temperature °C Bending Load N XNa+ YBr- YCO3 2- 1st Time 2nd Time 1 100 100 0 747 757 393 377 2 100 90 10 710 720 2078 1590 3 100 80 20 680 690 2413 1028 4 100 70 30 650 660 2652 2266 5 100 60 40 648 658 2139 1664 6 100 50 50 705 715 3750 3224 7 100 40 60 735 745 4115 3078 8 100 30 70 772 782 3239 2938 9 100 20 80 807 817 3053 2672 10 100 10 90 837 847 1919 1605 Reference 100 0 100 856 866 347 219 -
Table 2 Sample Number Cation Ratio mol% Anion Ratio mol% Liquidus Temperature °C Molding Temperature °C Bending Strength MPa XNa+ YBr- YCO3 2- 1st Time 2nd Time 1 100 100 0 747 757 3.3 3.1 2 100 90 10 710 720 17.3 13.2 3 100 80 20 680 690 20.1 8.6 4 100 70 30 650 660 22.1 18.9 5 100 60 40 648 658 17.8 13.9 6 100 50 50 705 715 31.2 26.9 7 100 40 60 735 745 34.3 25.7 8 100 30 70 772 782 27.0 24.5 9 100 20 80 807 817 25.4 22.3 10 100 10 90 837 847 16.0 13.4 Reference 100 0 100 856 866 2.9 1.8 - Tables 3 and 4 and
Fig. 3 show a change in bending strength (measurement value) occurring when the anion ratio of bromine ions to carbonate ions is changed in an expendable salt core manufactured by melting a salt mixture of potassium bromide and potassium carbonate. This refers to cases in which the molten salt to form the expendable salt core is formed of potassium ions, bromine ions, and carbonate ions. Table 3 shows the measurement results (maximum bending loads) of the bending strengths of the fabricated test pieces, and Table 4 shows the measurement results (maximum bending strengths) of the bending strengths of the fabricated test pieces. Tables 3 and 4 are identical except that representations of the measurement results are different. The concentration of each ion is measured according to the analysis method determined by the rules of ion chromatograph analysis of JIS standard K0127. As shown in Tables 3 and 4 andFig. 3 , expendable salt cores in which the concentration YCO3 2- of carbonate ions in all the cations is 60 mol% to 80 mol% exhibit high bending strengths exceeding a bending strength of 16.0 MPa. -
Table 3 Sample Number Cation Ratio Anion Ratio mol% Liquidus Temperature °C Molding Temperature °C Bending Load N Xk+ YBr- YCO3 2- 1st Time 2nd Time 1 100 100 0 734 744 346 323 2 100 90 10 704 714 1390 1288 3 100 80 20 674 684 828 724 4 100 70 30 634 644 1839 1492 5 100 60 40 680 690 1275 754 6 100 50 50 731 741 1747 1359 7 100 40 60 774 784 2504 2075 8 100 30 70 811 821 2666 1924 9 100 20 80 838 848 2837 1358 10 100 10 90 867 877 1757 1638 Reference 100 0 100 901 911 451 394 -
Table 4 Sample Number Cation Ratio mol% Anion Ratio mol% Liquidus Temperature °C Molding Temperature °C Bending Strength MPa Xk+ YBr- YCO3 2- 1st Time 2nd Time 1 100 100 0 734 744 2.9 2.7 2 100 90 10 704 714 11.6 10.7 3 100 80 20 674 684 6.9 6.0 4 100 70 30 634 644 15.3 12.4 5 100 60 40 680 690 10.6 6.3 6 100 50 50 731 741 14.6 11.3 7 100 40 60 774 784 20.9 17.3 8 100 30 70 811 821 22.2 16.0 9 100 20 80 838 848 23.6 11.3 10 100 10 90 867 877 14.6 13.6 Reference 100 0 100 901 911 3.8 3.3 - Tables 5, 6, and 7 show a change in bending strength (measurement value) occurring when the anion ratio of bromine ions to carbonate ions is changed in an expendable salt core manufactured by melting a salt mixture of sodium bromide, potassium bromide, potassium carbonate, and sodium carbonate. This refers to cases in which the molten salt to form the expendable salt core is formed of sodium ions, potassium ions, bromine ions, and carbonate ions. The following Tables 5, 6, and 7 show the measurement results (maximum bending strengths) of the bending strengths of the fabricated test pieces. The concentration of each ion is measured according to the analysis method determined by the rules of ion chromatograph analysis of JIS standard K0127, in the same manner as described above.
-
Table 5 Sample Number Cation Ratio mol% Anion Ratio mol% Liquidus Temperature °C Molding Temperature °C Bending Strength MPa XNa+ XK+ YBr- YCO3 2- 1st Time 2nd Time 1 50 50 80 20 635 645 0.77 2.39 2 40 60 80 20 650 660 1.78 2.28 3 30 70 80 20 665 675 5.13 8.15 4 20 80 80 20 680 690 10.58 10.77 5 10 90 80 20 675 685 14.18 12.42 6 80 20 70 30 630 640 0.87 0.48 7 60 40 70 30 635 645 3.83 1.07 8 50 50 70 30 630 640 6.46 6.80 9 40 60 70 30 650 660 12.54 15.96 10 30 70 70 30 660 670 13.93 14.60 11 20 80 70 30 655 665 13.15 13.34 12 10 90 70 30 660 670 13.75 12.56 13 80 20 60 40 660 670 8.00 6.95 14 70 30 60 40 660 670 8.28 8.81 15 60 40 60 40 655 665 10.26 9.71 16 50 50 60 40 7.08 17 40 60 60 40 635 645 10.01 9.34 18 30 70 60 40 635 645 13.56 16.54 19 20 80 60 40 625 635 12.64 11.66 20 10 90 60 40 620 630 6.66 6.89 -
Table 6 Sample Number Cation Ratio mol% Anion Ratio mol% Liquidus Temperature °C Molding Temperature °C Bending Strength MPa XNa+ XK+ YBr- YCO3 2- 1st Time 2nd Time 21 90 10 50 50 705 715 11.53 12.09 22 80 20 50 50 700 710 10.43 9.66 23 70 30 50 50 690 700 14.32 8.10 24 60 40 50 50 655 665 13.32 13.15 25 40 60 50 50 615 625 14.25 12.38 26 30 70 50 50 615 625 7.26 6.86 27 20 80 50 50 610 620 15.31 17.21 28 10 90 50 50 665 675 14.48 17.86 29 90 10 40 60 730 740 11.32 13.14 30 80 20 40 60 720 730 12.77 12.87 31 70 30 40 60 700 710 7.83 10.00 32 60 40 40 60 660 670 11.25 14.08 33 50 50 40 60 630 640 11.97 9.49 34 40 60 40 60 605 615 13.90 13.90 35 30 70 40 60 620 630 17.73 15.28 36 20 80 40 60 660 670 10.65 17.58 37 10 90 40 60 715 725 16.10 16.41 -
Table 7 Sample Number Cation Ratio mol% Anion Ratio mol% Liquidus Temperature °C Molding Temperature °C Bending Strength MPa XNa+ XK+ YBr- YCO3 2- 1st Time 2nd Time 38 60 40 30 70 670 680 8.96 10.45 39 50 50 30 70 640 650 15.84 27.79 40 40 60 30 70 635 645 17.31 14.44 41 30 70 30 70 660 670 16.95 15.88 42 20 80 30 70 690 700 17.57 15.38 43 10 90 30 70 760 770 20.46 17.81 44 90 10 20 80 790 800 7.04 8.2 45 80 20 20 80 760 770 7.06 7.61 46 70 30 20 80 720 730 6.7 6.82 47 60 40 20 80 685 695 7.43 6.08 48 50 50 20 80 660 670 21.3 23.44 49 40 60 20 80 675 685 18.06 16.14 50 30 70 20 80 715 725 12.09 13.28 51 20 80 20 80 758 768 8.6 9.28 -
Fig. 4 shows the relationship (phase diagram of Na-K-Br-CO3 system) among the cation ratio of potassium ions, the anionic ratio of carbonate ions, and the melting temperature (liquidus temperature). This corresponds to the results of the above Tables 2, 4, 5, 6, and 7. The largest circles represent test pieces that exhibit an average bending strength exceeding 20 MPa. The second largest circles represent test pieces that exhibit an average bending strength of 15 MPa to 20 MPa. The third largest circles represent test pieces that exhibit an average bending strength of 10 MPa to 15 MPa. The smallest circles represent test pieces that exhibit an average bending strength of 0 MPa to 10 MPa.Fig. 4 also shows the liquidus temperature of NaBr when K+ is 0 mol% and CO3 2- is 0 mol%, the liquidus temperature of KBr when Na+ is 0 mol% and CO3 2- is 0 mol%, the liquidus temperature of Na2CO3 when K+ is 0 mol% and Br- is 0 mol%, and the liquidus temperature of K2CO3 when Na+ is 0 mol% and Br- is 0 mol%. InFig. 4 , thick lines represent eutectic lines. - As shown in Tables 5, 6, and 7 and
Fig. 4 , when the molten salt is formed of sodium ions, potassium ions, bromine ions, and carbonate ions, a high bending strength exceeding a bending strength of 16.0 MPa is obtained with an expendable salt core in which a concentration XK- (molar ratio) of potassium ions in all the cations is 50 mol% to 90 mol% and the concentration YCO3 2- (molar ratio) of carbonate ions in all the anions is 40 mol% to 80 mol% with the melting temperature falling within a range of 600°C to 680°C. From the viewpoints of durability of the mold that forms the core and the process cost necessary to form the core, the melting temperature of the molten salt may be set to approximately 680°C at maximum. - The observation results with a scanning electron microscope (SEM) of the solidification structures of the expendable salt cores described above will be described.
Fig. 5 is an SEM photograph of the solidification structure of an expendable salt core fabricated using a molten salt in which the concentration of potassium ions in all the cations is 50 mol% and the concentration of carbonate ions in all the anions is 70 mol%. The expendable salt core fabricated from the molten salt with this composition exhibits a bending strength of 20 MPa or more, as shown inFig. 4 , thus providing a very high strength. In this expendable salt core, as shown inFig. 5 , a state is observed in which a plurality of granular crystals are evenly dispersed in the parent phase. The composition of the granular crystal portion observed in this manner was analyzed by an energy-dispersive X-ray spectroscopic analyzer. The concentration of potassium ions in all the cations was 32 mol%, and the concentration of carbonate ions in all the anions was 100 mol%. -
Fig. 6 is an SEM photograph of the solidification structure of an expendable salt core fabricated using a molten salt in which the concentration of potassium ions in all the cations is 60 mol% and the concentration of carbonate ions in all the anions is 70 mol%. The expendable salt core fabricated from the molten salt with this composition exhibits a bending strength of 15 MPa to 20 MPa, as shown inFig. 4 , thus providing a high strength. In this expendable salt core, as shown inFig. 6 , a state is observed in which a plurality of granular crystals are evenly dispersed in the parent phase. The composition of the granular crystal portion observed in this manner was analyzed by the energy-dispersive X-ray spectroscopic analyzer. The concentration of potassium ions in all the cations was 42 mol%, and the concentration of carbonate ions in all the anions was 100 mol%. -
Fig. 7 is an SEM photograph of the solidification structure of an expendable salt core fabricated using a molten salt in which the concentration of potassium ions in all the cations is 40 mol% and the concentration of carbonate ions in all the anions is 70 mol%. The expendable salt core fabricated from the molten salt with this composition exhibits a bendingstrength 0 MPa to 10 MPa, as shown inFig. 4 , and does not provide a very high strength. In this expendable salt core, as shown inFig. 7 , comparatively large dendrites are observed in the parent phase. The composition of the dendrite portion observed in this manner was analyzed by the energy-dispersive X-ray spectroscopic analyzer. The concentration of potassium ions in all the cations was 22 mol%, and the concentration of carbonate ions in all the anions was 100 mol%. - From the above description, to obtain an expendable salt core with a higher strength, a plurality of granular crystals need to be formed in the parent phase in a dispersed manner. The granular crystals and dendrites observed by the SEM described above are crystals (primary crystals) which are formed first in the cooling process of the molten salt, and have comparatively high melting temperatures. After primary crystals are formed, the portion containing eutectic mixtures having a comparatively low melting point solidifies to form parent phase portions around the primary crystals. If the primary crystals formed in the parent phase of eutectic mixtures in this manner are not large dendrites but smaller granular crystals, the obtained expendable salt core may provide a high strength.
- The above discussion often holds true for composition ratios other than those shown in
Figs. 5, 6 , and7 . For example, an expendable salt core formed of sodium ions, bromine ions, and carbonate ions and not containing potassium ions exhibits a high bending strength when the concentration of carbonate ions in all the anions is 30 mol% or falls between 50 mol% to 80 mol%. Of this molar ratio range, when the concentration of carbonate ions is 60 mol%, a state is also observed in the solidification structure of the expendable salt core in which a plurality of granular crystals are dispersed in the parent phase. - As is known well, NaBr is a fragile substance that causes cleavage fracture. With NaBr, only a low bending strength of less than 10 MPa is obtained, as described above. In contrast to this, when a carbonate is added to form the salt mixture, the solidified structure is formed of NaBr and Na2CO3, thus providing a higher bending strength. An expendable salt core having a high strength can be obtained not only by simply adding a carbonate, but also by selecting a composition in which a crystal structure having a comparatively high melting point is formed in the parent phase having a comparatively low melting point. As primary crystals are mixed in the parent phase, progress of cracks and the like may be interfered with, providing a high strength. If the primary crystals are large dendrites, cracks tend to progress. If the primary crystals are smaller granular crystals, a higher strength can be obtained as described above.
- Measurement of the bending strength will be described. To measure the bending strength, a prismatic test piece with a predetermined size is fabricated. A load is applied to the test piece, and the bending load is obtained from the maximum load needed to break the test piece. Fabrication of the test piece will be described first. A rod-
like test piece 901 as shown inFigs. 9A and 9B is formed using a predetermined metal mold. The employed metal mold is made of chrome molybdenum steel, e.g., SCM440H.Fig. 9A also showsriser portions 902 used when charging the metal mold with a melt. In measurement of the bending strength, theportions 902 are cut off.Fig. 9A is a side view, andFig. 9B is a sectional view taken at the position b - b inFig. 9A . The sizes indicated inFigs. 9A and 9B are design values of the metal mold. - To measure the bending strength of the rod-
like test piece 901 fabricated in the above manner, first, as shown inFig. 10 , thetest piece 901 is supported by twosupport portions 1001 arranged at the center of thetest piece 901 at a gap of 50 mm from each other. In this support state, at the intermediate portion of the twosupport portions 1001, twoload portions 1002 at a gap of 10 mm from each other apply a load to thetest piece 901. The load to be applied to thetest piece 901 is gradually increased. The maximum load needed to break thetest piece 901 was the bending load shown in Tables 1 and 3. - A bending strength σ (MPa) can be obtained from a bending load P in accordance with an equation σ = 3LP/BH2 where H is the length of the load direction in the section of the test piece, B is a length perpendicular to the load direction in the section of the test piece, and L is the distance from the
support portions 1001 serving as fulcrums to theload portions 1002 where the load acts. Although thetest piece 901 is formed by pouring the melt into the metal mold, it is difficult to form a test piece having a shape completely coinciding with the size true to the mold due to flow marks or shrinkage cavity. Therefore, the bending strength is calculated based on an approximation that the test piece has a rectangular section and that H ≈ 20 mm, B ≈ 18 mm, and L = 20 mm. Due to this approximation, the estimated strength is lower than the actual strength by approximately 0% to 20%. For example, it can be assumed that a test piece which is broken by a bending load of 1200N is stronger than an ideal test piece having a bending strength of 10 MPa. - The present invention can be suitably used as a core in casting such as aluminum die casting.
Claims (9)
- An expendable salt core for casting,
characterized by
being formed of a molten salt containing bromine ions, carbonate ions, and at least one of sodium ions and potassium ions. - An expendable salt core for casting according to claim 1, characterized in that
said molten salt is formed of sodium ions, bromine ions, and carbonate ions. - An expendable salt core for casting according to claim 2, characterized in that
in said molten salt, a molar ratio of carbonate ions in all the anions is 30 mol%. - An expendable salt core for casting according to claim 2, characterized in that
in said molten salt, a molar ratio of carbonate ions in all the anions is 50 mol% to 80 mol%. - An expendable salt core for casting according to claim 1, characterized in that
said molten salt is formed of potassium ions, bromine ions, and carbonate ions, and a molar ratio of carbonate ions in all the anions is 30 mol%. - An expendable salt core for casting according to claim 1, characterized in that
said molten salt is formed of potassium ions, bromine ions, and carbonate ions, and a molar ratio of carbonate ions in all the anions is 50 mol% to 90 mol%. - An expendable salt core for casting according to claim 1, characterized in that
said molten salt is formed of sodium ions, potassium ions, bromine ions, and carbonate ions,
a melting temperature of the molten salt falls within a range of 600°C to 680°C,
a molar ratio of potassium ions in all the cations is 50 mol% to 90 mol%, and
a molar ratio of carbonate ions in all the anions is 40 mol% to 80 mol%. - An expendable salt core for casting according to claim 1, characterized in that
a plurality of granular crystals are formed in a parent phase in a dispersed state. - An expendable salt core for casting according to claim 8, characterized in that
said granular crystals are formed of carbonate ions and at least one of sodium ions and potassium ions.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP2006140063 | 2006-05-19 | ||
PCT/JP2007/060369 WO2007136032A1 (en) | 2006-05-19 | 2007-05-21 | Salt core for casting |
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EP2022578A1 true EP2022578A1 (en) | 2009-02-11 |
EP2022578A4 EP2022578A4 (en) | 2013-08-28 |
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EP07743803.4A Withdrawn EP2022578A4 (en) | 2006-05-19 | 2007-05-21 | Salt core for casting |
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US (1) | US20090288797A1 (en) |
EP (1) | EP2022578A4 (en) |
JP (1) | JP4685934B2 (en) |
WO (1) | WO2007136032A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2586546A1 (en) * | 2011-10-31 | 2013-05-01 | Bühler AG | Method for preparing salt cores |
DE102012022390B3 (en) * | 2012-11-15 | 2014-04-03 | Audi Ag | Preparing a salt core for the formation of cavities in a light-metal die-casting, comprises introducing a paste-like salt-liquid mixture into cavity of compression mold, and compressing the mixture to expel fluid contained in the mixture |
CN103801671A (en) * | 2014-01-21 | 2014-05-21 | 北京交通大学 | Method and dies for manufacturing oxygen lance nozzle blank |
WO2014108419A1 (en) * | 2013-01-09 | 2014-07-17 | Emil Müller GmbH | Salt cores infiltrated with molten salt, preferably for diecasting applications |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
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ITMI20120950A1 (en) | 2012-06-01 | 2013-12-02 | Flavio Mancini | METHOD AND PLANT TO OBTAIN DIE-CASTING JETS IN LIGHT ALLOYS WITH NON-METALLIC SOURCES |
US8820389B1 (en) * | 2012-10-31 | 2014-09-02 | Brunswick Corporation | Composite core for the casting of engine head decks |
US9527131B1 (en) * | 2013-12-20 | 2016-12-27 | Brunswick Corporation | Congruent melting salt alloys for use as salt cores in high pressure die casting |
KR102478505B1 (en) * | 2016-12-23 | 2022-12-15 | 현대자동차주식회사 | Saltcore For Die-casting with Aluminum and the Method Therefor |
KR102215760B1 (en) * | 2017-01-19 | 2021-02-15 | 현대자동차주식회사 | Saltcores Having Improved Strength of Adhesive Part For High Pressure For Die-casting |
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US3501320A (en) * | 1967-11-20 | 1970-03-17 | Gen Motors Corp | Die casting core |
JPS5314618A (en) * | 1976-07-28 | 1978-02-09 | Hitachi Ltd | Water soluble casting mould |
WO2005028142A1 (en) * | 2003-09-17 | 2005-03-31 | Yamaha Hatsudoki Kabushiki Kaisha | Core for use in casting |
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JPS4839696B1 (en) * | 1969-12-27 | 1973-11-26 | ||
JPS4839696A (en) | 1971-09-27 | 1973-06-11 | ||
JPS5215446B2 (en) | 1974-04-19 | 1977-04-30 | ||
JPS5210803A (en) | 1975-07-12 | 1977-01-27 | Inst Gorunogo Dera Akademii Na | Device for retaining shank of cold chisel |
-
2007
- 2007-05-21 US US12/301,078 patent/US20090288797A1/en not_active Abandoned
- 2007-05-21 JP JP2008516682A patent/JP4685934B2/en active Active
- 2007-05-21 WO PCT/JP2007/060369 patent/WO2007136032A1/en active Application Filing
- 2007-05-21 EP EP07743803.4A patent/EP2022578A4/en not_active Withdrawn
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
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US3501320A (en) * | 1967-11-20 | 1970-03-17 | Gen Motors Corp | Die casting core |
JPS5314618A (en) * | 1976-07-28 | 1978-02-09 | Hitachi Ltd | Water soluble casting mould |
WO2005028142A1 (en) * | 2003-09-17 | 2005-03-31 | Yamaha Hatsudoki Kabushiki Kaisha | Core for use in casting |
Non-Patent Citations (1)
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Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2586546A1 (en) * | 2011-10-31 | 2013-05-01 | Bühler AG | Method for preparing salt cores |
WO2013064304A1 (en) * | 2011-10-31 | 2013-05-10 | Bühler AG | Method for producing salt cores |
DE102012022390B3 (en) * | 2012-11-15 | 2014-04-03 | Audi Ag | Preparing a salt core for the formation of cavities in a light-metal die-casting, comprises introducing a paste-like salt-liquid mixture into cavity of compression mold, and compressing the mixture to expel fluid contained in the mixture |
WO2014108419A1 (en) * | 2013-01-09 | 2014-07-17 | Emil Müller GmbH | Salt cores infiltrated with molten salt, preferably for diecasting applications |
CN103801671A (en) * | 2014-01-21 | 2014-05-21 | 北京交通大学 | Method and dies for manufacturing oxygen lance nozzle blank |
CN103801671B (en) * | 2014-01-21 | 2016-07-13 | 北京交通大学 | A kind of manufacture method of oxygen gun sprayer blank |
Also Published As
Publication number | Publication date |
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JPWO2007136032A1 (en) | 2009-10-01 |
EP2022578A4 (en) | 2013-08-28 |
WO2007136032A1 (en) | 2007-11-29 |
JP4685934B2 (en) | 2011-05-18 |
US20090288797A1 (en) | 2009-11-26 |
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