According to the invention, by setting the linear thermal expansion amount when a mold made of a molding sand is heated from a room temperature to 1000° C. to be not more than 0.9%, and the ratio (D/d) between the diameter of a slump (D) and the diameter of a slump cone (d) in a slump test of the molding sand having a hardening agent kneaded to be not less than 1.65, a molding sand preferable for use in a mold produced using the self-hardening type of three dimensional laminate molding sand mold, having low thermal expansibility preventing occurrence of a veining defect, and capable of forming a large and complicated shape can be obtained.
C04B 35/66 - Réfractaires monolithiques ou mortiers réfractaires, y compris ceux contenant de l'argile
B22C 1/10 - Compositions des matériaux réfractaires pour moules ou noyauxLeur structure granulaireCaractéristiques chimiques ou physiques de la mise en forme ou de la fabrication des moules caractérisées par des additions pour applications particulières, p. ex. indicateurs, addition pour faciliter la destruction du moule pour influencer la tendance au durcissement du matériau du moule
B22C 9/02 - Moules en sable ou moules analogues pour pièces coulées
B33Y 70/00 - Matériaux spécialement adaptés à la fabrication additive
B22C 1/02 - Compositions des matériaux réfractaires pour moules ou noyauxLeur structure granulaireCaractéristiques chimiques ou physiques de la mise en forme ou de la fabrication des moules caractérisées par des additions pour applications particulières, p. ex. indicateurs, addition pour faciliter la destruction du moule
B22C 1/22 - Compositions des matériaux réfractaires pour moules ou noyauxLeur structure granulaireCaractéristiques chimiques ou physiques de la mise en forme ou de la fabrication des moules caractérisées par l'emploi des agents liantsMélange d'agents liants d'agents organiques de résines naturelles ou synthétiques
The present invention provides a molding sand which is suitably usable in making a self-curing sand mold by a rapid prototyping technique and which makes it possible to form a large-sized mold that has a complicated shape and that exhibits such a low thermal expansion as to prevent veining. This molding sand satisfies the requirements: a mold produced using the molding sand exhibits a linear thermal expansion of 0.9% or less when heated from ordinary temperature to 1000°C; and a kneaded mixture of the molding sand and a curing agent exhibits a D/d ratio of slump diameter (D) to slump cone diameter (d) of 1.65 or more in a slump test.
B22C 1/00 - Compositions des matériaux réfractaires pour moules ou noyauxLeur structure granulaireCaractéristiques chimiques ou physiques de la mise en forme ou de la fabrication des moules
B22C 9/02 - Moules en sable ou moules analogues pour pièces coulées
ASAHI ORGANIC CHEMICALS INDUSTRY CO., LTD. (Japon)
KIMURA CHUZOSHO CO., LTD. (Japon)
ASAHI TSUSHO CORPORATION (Japon)
Inventeur(s)
Ogawa, Fumiyuki
Ikeda, Takuya
Hori, Shigeru
Hozumi, Hiroki
Fukuda, Yoya
Hayashi, Kenichi
Takada, Yoshiharu
Abrégé
Disclosed is an improved manufacturing method of casting molds wherein, in the periphery of aeration openings of the forming mold, RCS binder outflow prone to occur during aeration with steam is prevented, thereby not only resolving problems with the formed mold surface, but also improving separability of the mold during demolding from the forming mold and improving the effective strength of the obtained mold. The disclosed manufacturing method of casting molds involves (a) a first step for preparing dry-state resin-coated sand that is flowable at room temperature, obtained by kneading and mixing pre-heated molding sand and an aqueous solution of a water-soluble alkaline resole resin, (b) a second step in which, after filling said prepared resin-coated sand into a heated forming mold, the obtained filling phase is aerated at a pressure of 0.1MPa or less with steam at a temperature of less than 100C, moistening and cohering the resin-coated sand constituting said filling phase, and (c) a third step for curing the filling phase of the resin-coated sand that has been moistened and cohered.
B22C 9/02 - Moules en sable ou moules analogues pour pièces coulées
B22C 1/00 - Compositions des matériaux réfractaires pour moules ou noyauxLeur structure granulaireCaractéristiques chimiques ou physiques de la mise en forme ou de la fabrication des moules
B22C 1/10 - Compositions des matériaux réfractaires pour moules ou noyauxLeur structure granulaireCaractéristiques chimiques ou physiques de la mise en forme ou de la fabrication des moules caractérisées par des additions pour applications particulières, p. ex. indicateurs, addition pour faciliter la destruction du moule pour influencer la tendance au durcissement du matériau du moule
B22C 1/22 - Compositions des matériaux réfractaires pour moules ou noyauxLeur structure granulaireCaractéristiques chimiques ou physiques de la mise en forme ou de la fabrication des moules caractérisées par l'emploi des agents liantsMélange d'agents liants d'agents organiques de résines naturelles ou synthétiques
B22C 9/12 - Traitement des moules ou noyaux, p. ex. séchage, étuvage
4.
METHOD FOR REMOVING IMPURITIES IN MOLTEN CAST IRON, AND CAST IRON RAW MATERIAL
Disclosed is a method for removing the impurity elements Mn, Al, Ti, Pb, Zn and B in molten cast iron, which allows obtaining a clean molten metal in which depletion of useful C and Si is suppressed. An excess oxygen flame with a theoretical combustion ratio of fuel and oxygen of 1 to 1.5 (oxygen volume × 5 / fuel volume) is directly exposed to the surface of the pre-melted molten cast iron, overheating said melt surface, and the temperature of the aforementioned cast iron melt is maintained at 1250C or more but less than 1500C and a gas containing oxygen injected into the molten cast iron while causing said melt and the acid slag layer to contact.
A method for accurately predicting presence or absence of shrinkage cavity for prevention prior to casting for various shapes of cast metals or each portion of the cast metal. In a coagulation simulation process of a cast metal product, a differential pressure ΔP is determined from the equation given below: ΔP = k*dQ/dt*1/(wts/L+Lts/w+Lw/ts)*1/G3+b Occurrence of shrinkage cavity is predicted depending on whether or not the calculated value exceeds the specified value (judgment value). Further, when it is predicted that shrinkage cavity occurs, occurrence of shrinkage cavity is prevented by dividing a final coagulation portion by the use of a cooling metal or riser such that the calculated value never exceeds the judgment value.
A method of metal surface hardening treatment inducing transformation, in which transformation is induced in a surface interior of material as hardening treatment object by simple, rapid treatment utilizing a frictional heat under pressure without the occurrence of melt loss, quench crack, soft spot, deformation, etc. to thereby reform the structure of surface interior of material as hardening treatment object into a miniaturized martensitic structure. The method of surface hardening treatment comprised the steps of while rotating nearly cylindrical pressurization tool (2) at high velocity, pressing the bottom face thereof slightly into the surface of material as hardening treatment object (1) so as to attain application of given pressure, thereby generating a local frictional hear between the pressurization tool and the material as hardening treatment object; inducing transformation in the material as hardening treatment object at the locality having been exposed to the frictional heat; and when the surface of material as hardening treatment objent positioned in the vicinity of the pressurization tool starts to soften by the frictional heat, moving the pressurization tool.
A method of metal surface hardening treatment inducing transformation, in which transformation is induced in a surface interior of material as hardening treatment object by simple, rapid treatment utilizing a frictional heat under pressure without the occurrence of melt loss, quench crack, soft spot, deformation, etc. to thereby reform the structure of surface interior of material as hardening treatment object into a miniaturized martensitic structure. The method of surface hardening treatment comprises the steps of while rotating nearly cylindrical pressurization tool (2) at high velocity, pressing the bottom face thereof slightly into the surface of material as hardening treatment object (1) so as to attain application of given pressure, thereby generating a local frictional heat between the pressurization tool and the material as hardening treatment object; inducing transformation in the material as hardening treatment object at the locality having been exposed to the frictional heat; and when the surface of material as hardening treatment object positioned in the vicinity of the pressurization tool starts to soften by the frictional heat, moving the pressurization tool.
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