Abstract: A mold wash is used in a casting method using a lost foam to make a casting having a hole with a diameter of 12 mm or less. The casting method includes determining a thermal decomposition amount ?C(?,t) [wt %] of a resin binder when the mold wash is exposed at a temperature ? [° C.] for a time t [sec], and determining a room temperature transverse rupture strength ?b(?,t) [MPa] of the mold wash after receiving thermal loads, and performing casting with the mold wash having the room temperature transverse rupture strength ?b(?,t) after receiving thermal loads being equal to or larger than a threshold value ?cr [MPa].

Abstract: A core molding method for molding a core having a twisted shape by use of a core mold includes a curing step and a mold extracting step. In the curing step, after the core mold is disposed along a vertical direction within a frame whose top is open, a self-hardening sand formed of a kneaded mixture of a sand, a resin and a curing agent is charged into the frame from the top of the frame, and then cured. In the mold extracting step, the core mold is extracted in the vertical direction from the core formed of the cured self-hardening sand while rotating the core mold and the frame relatively to each other around an axis of the core mold.

Abstract: A mold molding method includes a binder reaction amount calculation step of calculating a reaction amount ?C(?, ti) [wt %] (i=1, 2) of a binder, a specimen room temperature compressive strength calculation step of calculating room temperature compressive strength ?c(?, t) [MPa] of a specimen, a mold room temperature compressive strength prediction step of predicting room temperature compressive strength ?ca(?, t) of the mold in advance, and a mold room temperature compressive strength extraction step of extracting room temperature compressive strength ?ce(?, t) of the mold. When the mold is actually molded, the model is removed just after elapse of the time t1, as one of the molding condition parameters which satisfies the room temperature compressive strength ?ce(?, t).

Abstract: A mold wash is used in a casting method using a lost foam to make a casting having a hole with a diameter of 12 mm or less. The casting method includes determining a thermal decomposition amount ?C(?,t) [wt %] of a resin binder when the mold wash is exposed at a temperature ? [° C.] for a time t [sec], and determining a room temperature transverse rupture strength ?b(?,t) [MPa] of the mold wash after receiving thermal loads, and performing casting with the mold wash having the room temperature transverse rupture strength ?b(?,t) after receiving thermal loads being equal to or larger than a threshold value ?cr [MPa].

Abstract: A mold molding method includes a binder reaction amount calculation step of calculating a reaction amount ?C(?, ti) [wt %] (i=1, 2) of a binder, a specimen room temperature compressive strength calculation step of calculating room temperature compressive strength ?c(?, t) [MPa] of a specimen, a mold room temperature compressive strength prediction step of predicting room temperature compressive strength ?ca(?, t) of the mold in advance, and a mold room temperature compressive strength extraction step of extracting room temperature compressive strength ?ce(?, t) of the mold. When the mold is actually molded, the model is removed just after elapse of the time t1, as one of the molding condition parameters which satisfies the room temperature compressive strength ?ce(?, t).

Abstract: A core molding method for molding a core having a twisted shape by use of a core mold includes a curing step and a mold extracting step. In the curing step, after the core mold is disposed along a vertical direction within a frame whose top is open, a self-hardening sand formed of a kneaded mixture of a sand, a resin and a curing agent is charged into the frame from the top of the frame, and then cured. In the mold extracting step, the core mold is extracted in the vertical direction from the core formed of the cured self-hardening sand while rotating the core mold and the frame relatively to each other around an axis of the core mold.

Abstract: The buoyancy transfer jig includes: a rod-shaped rod portion which is disposed extending from an outside of a pattern to an inside of a hollow portion by way of an opening portion which is formed in a foamed mold and makes the outside of the pattern and the hollow portion connected with each other, and is disposed in self hardening sand filled in the hollow portion and the opening portion; and a plate-shaped blade portion which is formed continuously with the rod portion and is disposed in the casting sand.

Abstract: An opening is provided in a foam pattern, and a coating agent is applied to the opening. The coating agent applied to the opening is taken as a beam having a sectional secondary moment I (mm4), a vertical plate thickness h (mm), and a length L (mm). It is assumed that a volume of a cavity part in the foam pattern is V (mm3), a bulk density of the casting sand filling the cavity part is ?s (kg/mm3), a gravitational acceleration is g (mm/sec2), a density of the melt is ?m (kg/mm3), an angle of the opening with respect to a vertical direction is ?, and a transverse strength of the coating agent at the highest temperature during pouring of the melt is ?b (MPa). A sectional shape of the opening, the angle ? of the opening, and the transverse strength ?b of the coating agent are selected to satisfy the expression: ?bI>V(?m??s)g{(hL/2)sin ??cos ?}.

Abstract: In the following expression, it is assumed that a thickness of a coating agent applied to a foam pattern [2] is t (mm), a diameter of a hole part [3] is D (mm), and a normal-temperature transverse strength of the dried coating agent is ?c (MPa). At the time of producing a casting provided with a hole having a diameter of 18 mm or smaller and a length of 1 (mm), a coating agent that satisfies the following expression is used when a solidification end time te (sec) at which solidification of a melt ends on a periphery of the hole part [3] is within a time t0 (sec) at which thermal decomposition of the coating agent ends. ?c?{t0/(t0?te)}×(1.

Abstract: For continuously casting an ingot of titanium or titanium alloy, molten titanium or titanium alloy is poured into a top opening of a bottomless mold with a circular cross-sectional shape, the solidified molten metal in the mold is pulled downward from the mold, a plurality of plasma torches disposed on an upper side of molten metal in the mold such that their centers are located directly vertically above the molten metal in the mold, are operated to generate plasma arcs that heat the molten metal in the mold, and the plasma torches are moved in a horizontal direction above a melt surface of the molten metal in the mold, along a trajectory located directly vertically above the molten metal in the mold, while keeping a mutual distance between the respective plasma torches such that the plasma torches do not interfere with each other.

Abstract: When a core die is being removed from a core while being rotated around its axis, the hardening time of self-hardening sand, the frictional forces generated between the core and the core die during die removal, and the strength of the core during die removal are optimized.

Abstract: Provided is a casting method using lost foam capable of forming a small highly-finished hole with a diameter of 18 mm or less and a length of 50 mm or more by casting. A casting method using lost foam of the present embodiment includes the steps of embedding, in foundry sand, a casting pattern formed by applying a mold wash with a thickness of 1 mm or more to a surface of the foam pattern, the foam pattern having a hole with a diameter of D (mm); replacing the foam pattern with molten metal by pouring the molten metal into the casting pattern and losing the foam pattern; and forming a casting having a small hole with a diameter of 18 mm or less and a length of 50 mm or more by cooling the molten metal, and the method satisfies the following formulas (0) and (1): 2<D?19.7??Formula (0) ?c??0.36+140/D2??Formula (1) where ?c (MPa) is transverse rupture strength (bending strength) of the mold wash that is heated to decompose resin constituting the mold wash and then returned to room temperature.

Abstract: The buoyancy transfer jig includes: a rod-shaped rod portion which is disposed extending from an outside of a pattern to an inside of a hollow portion by way of an opening portion which is formed in a foamed mold and makes the outside of the pattern and the hollow portion connected with each other, and is disposed in self hardening sand filled in the hollow portion and the opening portion; and a plate-shaped blade portion which is formed continuously with the rod portion and is disposed in the casting sand.

Abstract: In the following expression, it is assumed that a thickness of a coating agent applied to a foam pattern [2] is t (mm), a diameter of a hole part [3] is D (mm), and a normal-temperature transverse strength of the dried coating agent is ?c (MPa). At the time of producing a casting provided with a hole having a diameter of 18 mm or smaller and a length of 1 (mm), a coating agent that satisfies the following expression is used when a solidification end time te (sec) at which solidification of a melt ends on a periphery of the hole part [3] is within a time t0 (sec) at which thermal decomposition of the coating agent ends. ?c?{t0/(t0?te)}×(1.

Abstract: An opening is provided in a foam pattern, and a coating agent is applied to the opening. The coating agent applied to the opening is taken as a beam having a sectional secondary moment I, a vertical plate thickness h, and a length L. It is assumed that a volume of a cavity part in the foam pattern is V (mm3), a bulk density of the casting sand filling the cavity part is ?s (kg/mm3), a density of the melt is ?m (kg/mm3), an angle of the opening with respect to a vertical direction is ?, and a transverse strength of the coating agent at the highest temperature during pouring of the melt is ?b (MPa). A sectional shape of the opening, the angle ? of the opening, and the transverse strength ?b of the coating agent are selected to satisfy the expression: ?bI>V(?m??s){(hL/2)sin ??cos ?}.

Abstract: Provided is a casting method using lost foam capable of forming a small highly-finished hole with a diameter of 18 mm or less and a length of 50 mm or more by casting. A casting method using lost foam of the present embodiment includes the steps of embedding, in foundry sand, a casting pattern formed by applying a mold wash with a thickness of 1 mm or more to a surface of the foam pattern, the foam pattern having a hole with a diameter of D (mm); replacing the foam pattern with molten metal by pouring the molten metal into the casting pattern and losing the foam pattern; and forming a casting having a small hole with a diameter of 18 mm or less and a length of 50 mm or more by cooling the molten metal, and the method satisfies the following formulas (0) and (1): 2<D?19.7 ??Formula (0) ?c??0.36+140/D2 ??Formula (1) where ?c (MPa) is transverse rupture strength (bending strength) of the mold wash that is heated to decompose resin constituting the mold wash and then returned to room temperature.

Abstract: Provided is a device for titanium continuous casting (1) capable, even when continuously casting large diameter titanium ingots or titanium alloy ingots, of suppressing component segregation thereof. The device for titanium continuous casting (1) comprises: a mold (3) having an upper section having a circular upper opening (3a) for pouring in molten metal (6), and a bottom section having a lower opening for continuously drawing ingots (11); and a plurality of plasma torches (4, 5) to heat the molten metal in the mold (3) from the upper opening (3a) side. The plurality of plasma torches (4, 5) are disposed so that the amount of heat input to the molten metal (6) present in the outer circumference enclosing the center of the upper opening (3a) is greater than the amount of heat input to the molten metal (6) present in the center of the upper opening (3a).

Abstract: For continuously casting an ingot of titanium or titanium alloy, molten titanium or titanium alloy is poured into a top opening of a bottomless mold with a circular cross-sectional shape, the solidified molten metal in the mold is pulled downward from the mold, a plurality of plasma torches disposed on an upper side of molten metal in the mold such that their centers are located directly vertically above the molten metal in the mold, are operated to generate plasma arcs that heat the molten metal in the mold, and the plasma torches are moved in a horizontal direction above a melt surface of the molten metal in the mold, along a trajectory located directly vertically above the molten metal in the mold, while keeping a mutual distance between the respective plasma torches such that the plasma torches do not interfere with each other.

Abstract: By controlling the temperature (TS) of a surface portion (11a) of an ingot (11) in a contact region (16) between a mold (2) and the ingot (11) and/or a passing heat flux (q) from the surface portion (11a) of the ingot (11) to the mold (2) in the contact region (16), the thickness (D) in the contact region (16) of a solidified shell (13) obtained by the solidification of molten metal (12) is brought into a predetermined range. Consequently, an ingot having a good casting surface state can be cast.

Abstract: When a core die is being removed from a core while being rotated around its axis, the hardening time of self-hardening sand, the frictional forces generated between the core and the core die during die removal, and the strength of the core during die removal are optimized.