A molding material mixture for producing casting molds for metal processing, particularly for non-ferrous metals, such as aluminum or magnesium, is intended to reduce problems such as metal-mold reaction and/or shrinkage porosity defect. The free-flowing refractory molding material in the molding material mixture is coated with a mixture of inorganic salts exhibiting a eutectic melting point in the range of about 400 C to about 500 C, particularly in the range of about 420 C to about 460 C. Preferably this coating occurs by contacting the inorganic salt mixture with the molding material mixture at a temperature between 500 C and 700 C, in a manner that maintains the free-flowing nature of the coated product. One mixture of inorganic salts that is used is a mixture consisting of, by weight: 74% potassium fluoroborate; 15% potassium chloride; and 12% potassium fluoride. This mixture has a eutectic melting point of 420 C.

A molding material mixture for producing casting molds for metal processing, particularly for non-ferrous metals, such as aluminum or magnesium, is intended to reduce problems such as metal-mold reaction and/or shrinkage porosity defect. The free-flowing refractory molding material in the molding material mixture is coated with a mixture of inorganic salts exhibiting a eutectic melting point in the range of about 400 C to about 500 C, particularly in the range of about 420 C to about 460 C. Preferably this coating occurs by contacting the inorganic salt mixture with the molding material mixture at a temperature between 500 C and 700 C, in a manner that maintains the free-flowing nature of the coated product. One mixture of inorganic salts that is used is a mixture consisting of, by weight: 74% potassium fluoroborate; 15% potassium chloride; and 12% potassium fluoride. This mixture has a eutectic melting point of 420 C.

“A gypsum-based embedding material” is provided with which favorable casting can be conducted not only in the case where a conventional wax pattern is used, but also, in particular, in the case where a resin pattern different from the conventional wax pattern in disappearance temperature and disappearance behavior is used, and with which, although being a “gypsum-based embedding material”, occurrence of cracks, breakage, or the like in a mold is suppressed even when casting is conducted by “rapid heating” excellent in treatment efficiency. The gypsum-based embedding material composition for casting comprising, as main components, calcined gypsum as a binder, cristobalite and quartz as heat-expandable refractory materials, and a non-heat-expandable refractory material having an average particle diameter of 5 to 20 μm, the blending amount of the non-heat-expandable refractory material in 100 parts by mass of the main components being 10 to 25 parts by mass.

“A gypsum-based embedding material” is provided with which favorable casting can be conducted not only in the case where a conventional wax pattern is used, but also, in particular, in the case where a resin pattern different from the conventional wax pattern in disappearance temperature and disappearance behavior is used, and with which, although being a “gypsum-based embedding material”, occurrence of cracks, breakage, or the like in a mold is suppressed even when casting is conducted by “rapid heating” excellent in treatment efficiency. The gypsum-based embedding material composition for casting comprising, as main components, calcined gypsum as a binder, cristobalite and quartz as heat-expandable refractory materials, and a non-heat-expandable refractory material having an average particle diameter of 5 to 20 μm, the blending amount of the non-heat-expandable refractory material in 100 parts by mass of the main components being 10 to 25 parts by mass.

The object of the present invention is to provide an embedding material composition for casting that makes it possible to conduct a favorable casting in the case where casting is conducted using a resin pattern that is different from a conventional wax pattern in disappearance temperature and disappearance behaviors through “rapid heating” excellent in treatment efficiency. The present invention relates to an embedding material composition for casting not using a heat-expandable refractory material as a main component, comprising: a binder; and a non-heat-expandable refractory material having an average particle diameter of 5 to 20 μm as main components, in which a content of the binder is 25 to 40 parts by mass and a content of the non-heat-expandable refractory material is 60 to 75 parts by mass in the case where the total amount of the main components is 100 parts by mass, and the present invention also relates to a casting process using the embedding material composition for casting.

The object of the present invention is to provide an embedding material composition for casting that makes it possible to conduct a favorable casting in the case where casting is conducted using a resin pattern that is different from a conventional wax pattern in disappearance temperature and disappearance behaviors through “rapid heating” excellent in treatment efficiency. The present invention relates to an embedding material composition for casting not using a heat-expandable refractory material as a main component, comprising: a binder; and a non-heat-expandable refractory material having an average particle diameter of 5 to 20 μm as main components, in which a content of the binder is 25 to 40 parts by mass and a content of the non-heat-expandable refractory material is 60 to 75 parts by mass in the case where the total amount of the main components is 100 parts by mass, and the present invention also relates to a casting process using the embedding material composition for casting.

The present invention provides a gypsum-based embedding material composition for casting useful for forming a rapid-heating type gypsum-based embedding material and a method for producing the same. The gypsum-based embedding material is formed of the gypsum-based powdery embedding material composition by adding a malaxation liquid into the composition and heating the mixture in a high-temperature furnace. The gypsum-based embedding material composition contains as main components, at least one co-pulverized material selected from a co-pulverized material of calcined gypsum and quartz, that of calcined gypsum and cristobalite, and that of calcined gypsum, quartz, and cristobalite. The composition further contains a powdery moisture-retaining component or a liquid moisture-retaining component having a low water content, and has an average particle diameter of 30 μm or less.

The present invention provides a gypsum-based embedding material composition for casting useful for forming a rapid-heating type gypsum-based embedding material and a method for producing the same. The gypsum-based embedding material is formed of the gypsum-based powdery embedding material composition by adding a malaxation liquid into the composition and heating the mixture in a high-temperature furnace. The gypsum-based embedding material composition contains as main components, at least one co-pulverized material selected from a co-pulverized material of calcined gypsum and quartz, that of calcined gypsum and cristobalite, and that of calcined gypsum, quartz, and cristobalite. The composition further contains a powdery moisture-retaining component or a liquid moisture-retaining component having a low water content, and has an average particle diameter of 30 μm or less.

The invention concerns a method of manufacturing a shell mould (1) with several layers (2, 3, 4, 5), including at least one contact layer (2), from a model (6) of wax or other similar material of a part to be manufactured, the method comprising a step of dipping the model (6) into a contact slip forming the contact layer (2) and comprising an inorganic or organic binder and a powder, wherein the powder is a mullite-zirconia composite.

The invention concerns a method of manufacturing a shell mould (1) with several layers (2, 3, 4, 5), including at least one contact layer (2), from a model (6) of wax or other similar material of a part to be manufactured, the method comprising a step of dipping the model (6) into a contact slip forming the contact layer (2) and comprising an inorganic or organic binder and a powder, wherein the powder is a mullite-zirconia composite.