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: The present invention provides a method for casting a slab having a good cast surface. The method includes heating the surface of molten metal on a metal inlet side of a mold by a first heat source so that the following formulas: q?0.87 and c?11.762q+0.3095 are satisfied where c is a cycle time [sec] of turning movement of the first heat source, and q is an average amount of heat input [MW/m2] determined by accumulating an amount of heat input applied by at least the first heat source to the contact region between the upper surface of the slab on the metal inlet side and the mold, along the path of turning movement of the first heat source, and dividing the resultant accumulated value by the cycle time c.

Abstract: In the present invention the torch movement period is 20-40 seconds, with the torch movement period being the time required to move plasma torches (which heat the surface of molten metal in the casting mold) one time. The average heat input amount at multiple sites, which are obtained by dividing the initial solidification portion (which is where the molten metal makes contact with the casting mold and first solidifies) into multiple sites in the circumferential direction of the casting mold, is 1.0-2.0 MW/m2. The molten metal advection time, which is the time required for electromagnetically stirred molten metal to travel the length of the torch heating region of the surface of the molten metal in the lengthwise direction of the casting mold, is 3.5 seconds or less.

Abstract: In the present invention the torch movement period is 20-40 seconds, with the torch movement period being the time required to move plasma torches (which heat the surface of molten metal in the casting mold) one time. The average heat input amount at multiple sites, which are obtained by dividing the initial solidification portion (which is where the molten metal makes contact with the casting mold and first solidifies) into multiple sites in the circumferential direction of the casting mold, is 1.0-2.0 MW/m2. The molten metal advection time, which is the time required for electromagnetically stirred molten metal to travel the length of the torch heating region of the surface of the molten metal in the lengthwise direction of the casting mold, is 3.5 seconds or less.

Abstract: The present invention provides a method for casting a slab with good cast surface quality. The method includes pouring molten metal 8 into a mold 2 from one of the paired shorter sides of the mold 2 while allowing superheat ?T [° C.], which is a temperature difference obtained by subtracting the melting point Tm [° C.] of the raw material from the temperature Tin [° C.] of the molten material on the surface of the molten metal in the mold and at the pouring point of the molten metal, to satisfy the following Formula (1) and Formula (2): 0.0014?T2 +0.0144?T+699.45>800 ??Formula (1) 0.0008?T2 +0.2472?T+853.

Abstract: The present invention provides a method for casting a slab having a good cast surface. The method includes heating the surface of molten metal on a metal inlet side of a mold by a first heat source so that the following formulas: q?0.87 and c?11.762q+0.3095 are satisfied where c is a cycle time [sec] of turning movement of the first heat source, and q is an average amount of heat input [MW/m2] determined by accumulating an amount of heat input applied by at least the first heat source to the contact region between the upper surface of the slab on the metal inlet side and the mold, along the path of turning movement of the first heat source, and dividing the resultant accumulated value by the cycle time c.

Abstract: The present invention provides a method for casting a slab with good cast surface quality. The method includes pouring molten metal 8 into a mold 2 from one of the paired shorter sides of the mold 2 while allowing superheat ?T [° C.], which is a temperature difference obtained by subtracting the melting point Tm [° C.] of the raw material from the temperature Tin [° C.] of the molten material on the surface of the molten metal in the mold and at the pouring point of the molten metal, to satisfy the following Formula (1) and Formula (2): 0.0014?T2 +0.0144?T+699.45>800 ??Formula (1) 0.0008?T2 +0.2472?T+853.

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: In the present invention the torch movement period is 20-40 seconds, with the torch movement period being the time required to move plasma torches (which heat the surface of molten metal in the casting mold) one time. The average heat input amount at multiple sites, which are obtained by dividing the initial solidification portion (which is where the molten metal makes contact with the casting mold and first solidifies) into multiple sites in the circumferential direction of the casting mold, is 1.0-2.0 MW/m2. The molten metal advection time, which is the time required for electromagnetically stirred molten metal to travel the length of the torch heating region of the surface of the molten metal in the lengthwise direction of the casting mold, is 3.5 seconds or less.

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: Disclosed is a continuous casting method in which a melt obtained by melting titanium or a titanium alloy is poured into a bottomless mold and is drawn downward while being solidified, wherein: the surface of the melt in the mold is heated by horizontally moving a plasma torch over the surface of the melt; thermocouples are provided at a plurality of locations along the circumferential direction of the mold; if the temperature of the mold measured by one of the thermocouples is lower than a target temperature, then the output of the plasma torch is increased when the plasma torch comes close to the location where that thermocouple is installed; and if said temperature is higher than the target temperature, then the output of the plasma torch is decreased when the plasma torch comes close to the location where that thermocouple is installed.

Abstract: A continuous casting method in which a molten metal obtained by melting titanium or a titanium alloy is injected into a bottomless mold having a rectangular cross-section and withdrawn downward while being caused to solidify, wherein a plasma torch (7) is caused to rotate in the horizontal direction above the surface of the molten metal (12) in the mold (2), and a horizontally rotating flow is generated by electromagnetic stirring on at least the surface of the molten metal (12) in the mold (2). It is thereby possible to cast a slab in which the casting surface condition is excellent.

Abstract: A continuous casting apparatus continuously casts an ingot formed of titanium or a titanium alloy. The apparatus includes a bottomless mold with a circular cross-sectional shape and a plasma torch. In the bottomless mold, a molten metal is poured from a top opening and the molten metal is solidified and the molten metal solidified is pulled out downward. The plasma torch is disposed on an upper side of the molten metal in the mold and generates a plasma arc that heats the molten metal. A plurality of plasma torches are disposed on the upper side of the molten metal in the mold. The plurality of plasma torches are moved in a horizontal direction above a melt surface of the molten metal along a trajectory keeping a distance not to allow for interference with each other.

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: A continuous casting method in which a molten metal obtained by melting titanium or a titanium alloy is injected into a bottomless mold having a rectangular cross-section and withdrawn downward while being caused to solidify, wherein a plasma torch (7) is caused to rotate in the horizontal direction above the surface of the molten metal (12) in the mold (2), and a horizontally rotating flow is generated by electromagnetic stirring on at least the surface of the molten metal (12) in the mold (2). It is thereby possible to cast a slab in which the casting surface condition is excellent.

Abstract: Disclosed is a continuous casting method in which a melt obtained by melting titanium or a titanium alloy is poured into a bottomless mold and is drawn downward while being solidified, wherein: the surface of the melt in the mold is heated by horizontally moving a plasma torch over the surface of the melt; thermocouples are provided at a plurality of locations along the circumferential direction of the mold; if the temperature of the mold measured by one of the thermocouples is lower than a target temperature, then the output of the plasma torch is increased when the plasma torch comes close to the location where that thermocouple is installed; and if said temperature is higher than the target temperature, then the output of the plasma torch is decreased when the plasma torch comes close to the location where that thermocouple is installed.

Abstract: The continuous casting device according to the present invention enables at least some of a plurality of hearths (3) to be converted between being hearths (13) used for titanium, which are used during the continuous casting of titanium ingots, and being hearths (23) used for titanium alloy, which are used during the continuous casting of titanium alloy ingots. The number of hearths (23) used for titanium alloy is greater than the number of hearths (13) used for titanium. Also, the total capacity of the hearths (23) used for titanium alloy is greater than the total capacity of the hearths (13) used for titanium. Thus, titanium ingots and titanium alloy ingots can each be continuously cast by means of a single piece of equipment.

Abstract: A mold (2) has a cooling means (21) for having the thermal flux at four corner sections (2a) be smaller than the thermal flux at four face sections (2b). The cooling means (21) has first channels (22a) which are each embedded in the four corner sections (2a) respectively and which channel cooling water, and second channels (22b) which are each embedded in the four face sections (2b) respectively and which channel cooling water. The distance from the inner peripheral surface of the mold (2) to the first channels (22a) is greater than the distance from the inner peripheral surface of the mold (2) to the second channels (22b).

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.