A casting apparatus for producing castings using molds each having a sprue, comprising a mold-conveying means for conveying molds each containing a melt poured through the sprue; nozzles each having a gas-introducing opening attachable to and detachable from the sprue; nozzle-attaching/detaching means each moving each nozzle to attach and detach the gas-introducing opening to and from the sprue; moving means for moving the nozzle-attaching/detaching means, such that the nozzle-attaching/detaching means moves following a mold conveyed by the mold-conveying means, while keeping the connection of the gas-introducing opening to the sprue by the nozzle-attaching/detaching means; and a gas supply means connected to each nozzle for supplying a gas to the gas-introducing opening.

A method for casting comprising: providing a seed, the seed characterized by: an arcuate form and a crystalline orientation progressively varying along an arc of the form; providing molten material; and cooling and solidifying the molten material so that a crystalline structure of the seed propagates into the solidifying material.

A method for casting comprising: providing a seed, the seed characterized by: an arcuate form and a crystalline orientation progressively varying along an arc of the form; providing molten material; and cooling and solidifying the molten material so that a crystalline structure of the seed propagates into the solidifying material.

A method for producing a casting using a gas-permeable casting mold comprising a cavity composed of a production cavity and a flow path, the flow path comprising a sprue through which a gravity-poured melt flows downward, and a runner connecting the production cavity to the sprue, comprising gravity-pouring a metal melt in a volume smaller than that of the entire cavity and larger than that of the production cavity into the gas-permeable casting mold; supplying a gas through the sprue to push the metal melt in the flow path, thereby pushing the metal melt upward in the production cavity, so that the production cavity is filled with the metal melt; in a hypothetical equilibrium state in which a hypothetical liquid fills the production cavity by the supplied gas, setting the volume of the metal melt to be poured to be equal to the volume of the hypothetical liquid, such that the surface height hs of the hypothetical liquid remaining in the flow path after filling the production cavity, the height h1 of the lowest ceiling portion of the runner, and the height h2 of a point at which a ceiling of the runner is connected to the sprue, meet the relation of h2>hs>h1.

A method for producing a casting using a gas-permeable casting mold comprising a cavity composed of a production cavity and a flow path, the flow path comprising a sprue through which a gravity-poured melt flows downward, and a runner connecting the production cavity to the sprue, comprising gravity-pouring a metal melt in a volume smaller than that of the entire cavity and larger than that of the production cavity into the gas-permeable casting mold; supplying a gas through the sprue to push the metal melt in the flow path, thereby pushing the metal melt upward in the production cavity, so that the production cavity is filled with the metal melt; in a hypothetical equilibrium state in which a hypothetical liquid fills the production cavity by the supplied gas, setting the volume of the metal melt to be poured to be equal to the volume of the hypothetical liquid, such that the surface height hs of the hypothetical liquid remaining in the flow path after filling the production cavity, the height h1 of the lowest ceiling portion of the runner, and the height h2 of a point at which a ceiling of the runner is connected to the sprue, meet the relation of h2>hs>h1.

A method for producing a casting by pouring a metal melt by gravity into a gas-permeable casting mold having a cavity comprising at least a sprue, a runner and a product-forming cavity, comprises pouring a metal melt into a desired cavity portion including the product-forming cavity through the sprue, the melt being in a volume smaller than the volume of an entire cavity of the gas-permeable casting mold and substantially equal to the volume of the desired cavity portion; supplying a gas to the desired cavity portion through the sprue before the desired cavity portion is filled with the poured melt, so that the melt fills the desired cavity portion and solidifies; the gas being supplied from a gas-blowing nozzle fit into the sprue.

A method for producing a casting by pouring a metal melt by gravity into a gas-permeable casting mold having a cavity comprising at least a sprue, a runner and a product-forming cavity, comprises pouring a metal melt into a desired cavity portion including the product-forming cavity through the sprue, the melt being in a volume smaller than the volume of an entire cavity of the gas-permeable casting mold and substantially equal to the volume of the desired cavity portion; supplying a gas to the desired cavity portion through the sprue before the desired cavity portion is filled with the poured melt, so that the melt fills the desired cavity portion and solidifies; the gas being supplied from a gas-blowing nozzle fit into the sprue.

A method for casting comprising: providing a seed, the seed characterized by: an arcuate form and a crystalline orientation progressively varying along an arc of the form; providing molten material; and cooling and solidifying the molten material so that a crystalline structure of the seed propagates into the solidifying material.

A method for casting comprising: providing a seed, the seed characterized by: an arcuate form and a crystalline orientation progressively varying along an arc of the form; providing molten material; and cooling and solidifying the molten material so that a crystalline structure of the seed propagates into the solidifying material.

A casting tool for a piston may include a casting mold for forming a piston part from a casting melt and a casting head including a feeder for feeding the casting melt into the casting mold. The casting head may include a ring-shaped groove, and the groove may include an inner groove flank for forming the casting melt into a circumferential, ring-shaped sealing rib such that an inner rib flank of the sealing rib rests with a sealing effect against the inner groove flank when the casting melt solidifies in the groove. Additionally or alternatively, the casting head may include a ring-shaped collar, and the collar may include an outer collar flank for forming the casting melt to provide a circumferential, ring-shaped sealing groove such that an outer groove flank of the sealing groove rests with a sealing effect against the outer collar flank when the casting melt solidifies.