Abstract: A centrifugally cast composite roll comprising an outer layer formed by a centrifugal casting method, and an inner layer made of ductile cast iron and integrally fused to the outer layer; the outer layer being made of an Fe-based alloy having a chemical composition comprising by mass at least 0.8-3.0% of Cr, 1.5-6.0% of Mo, and 1.8-5.5% of V, and a metal structure in which the area ratio of graphite is 0.3-10%; the inner layer comprising a roll body portion fused to the outer layer, and shaft portions integrally extending from both ends of the roll body portion; and the total amount of Cr, Mo and V being 0.15-2.0% by mass in end portions of both shaft portions, and the difference in the total amount of Cr, Mo and V between one shaft portion and the other shaft portion being 0.2% or more by mass.

Abstract: The present invention provides a method for manufacturing a biocompatible precious metal alloy object. According to a first aspect melting of alloying elements and casting of the biocompatible precious metal alloy are carried out in a process chamber (11) being provided with a process gas of predetermined composition. A burning flame (19) of a hydrocarbon-containing gas provides low oxygen and water content. According to a second aspect post-processing of a precious metal alloy is made in atmosphere provided by the process gas to form the biocompatible precious metal alloy object. The biocompatible precious metal alloy object manufactured according to the invention has a low probability of causing sensitisation when in contact with the human body.

Abstract: An aluminum casting process using a casting mold in which after the cavity (25) is filled with an inert gas, magnesium is introduced into the cavity to have a magnesium layer (58a) deposited on the cavity wall. Then, nitrogen gas is introduced into the cavity to form magnesium nitride (58b) on the surface of the magnesium layer after the cavity wall is heated to a specific temperature. Then, molten aluminum is supplied to have an aluminum casting molded, while the surface of the molten aluminum (39) is reduced with magnesium nitride. This makes it possible to form magnesium nitride within a short time and decrease the amount of nitrogen gas as required.

Abstract: An aluminum casting process using a casting mold in which after the cavity (25) is filled with an inert gas, magnesium is introduced in to the cavity to have a magnesium layer (58a) deposited on the cavity wall. Then, nitrogen gas is introduced into the cavity to form magnesium nitride (58b) on the surface of the magnesium layer after the cavity wall is heated to a specific temperature. Then, molten aluminum is supplied to have an aluminum casting molded, while the surface of the molten aluminum (39) is reduced with magnesium nitride. This makes it possible to form magnesium nitride within a short time and decrease the amount of nitrogen gas as required.

Abstract: A reduction casting method includes the steps of: pouring a molten metal into a cavity of a molding die; and performing casting while reducing an oxide film formed on a surface of the molten metal by allowing the molten metal and a reducing substance to come into contact with each other in the cavity. On this occasion, the molten metal is poured into the cavity in a state in which the molding die is forcibly cooled by a cooling device, thereby being rapidly cooled. Further, on this occasion, a solidification speed at which the molten metal is rapidly cooled is allowed to be 600° C./min or more. Still further, on this occasion, the molten metal is filled into the cavity in a filling time of from 1.0 second to 9.0 seconds.

Abstract: An aluminum casting method includes the step of applying in advance a mold release agent including magnesium to a mold surface. Thereafter, a nitrogen gas is injected into a cavity to cause reaction between the magnesium in the surface of the mold release agent and the nitrogen gas, thereby forming magnesium nitride. Since the nitrogen gas reacts only with the magnesium exposed in the surface of the mold release agent, the forming time of the magnesium nitride is reduced and also the amount of nitrogen gas used is reduced.

Abstract: A casting apparatus for performing a casting while an oxide film formed on a surface of a molten metal is reduced by allowing the molten metal and a reducing compound to be contacted with each other, includes: a molding die having a cavity for receiving the molten metal, a sprue from which the molten metal is poured and a feeder head portion arranged between the sprue and the cavity. A difference of heat insulation is partially provided between the feeder head portion and the cavity such that the molten metal filled in the cavity and the feeder head portion is sequentially solidified in a direction of from a terminal portion of the cavity to the feeder head portion.

Abstract: A reduction casting method includes the steps of: allowing a metallic gas and a reactive gas to react with each other to generate a reducing compound; introducing the thus-generated reducing compound into a cavity of a molding die 11; and reducing an oxide film formed on a surface of a molten metal by the reducing compound to cast a cast product. The reduction casting method uses a non-reactive gas as a carrier gas when the metallic gas is introduced into the cavity, in which a flow quantity of the non-reactive gas is allowed to be from one sixth to twice that of the reactive gas.

Abstract: In a reduction casting method in which casting is performed while an oxide film formed on a surface of the molten metal is reduced, after an inside of a cavity of a molding die is allowed to be in a non-oxidizing atmosphere, a reducing substance having a stronger reducing property than a metal of the molten metal has is allowed to act on the molten metal whereupon casting is performed while the oxide film formed on the surface of the molten metal is reduced.

Abstract: A casting apparatus for performing a casting while an oxide film formed on a surface of a molten metal is reduced by allowing the molten metal and a reducing compound to be contacted with each other, includes: a molding die having a cavity for receiving the molten metal, a sprue from which the molten metal is poured and a feeder head portion arranged between the sprue and the cavity. A difference of heat insulation is partially provided between the feeder head portion and the cavity such that the molten metal filled in the cavity and the feeder head portion is sequentially solidified in a direction of from a terminal portion of the cavity to the feeder head portion.

Abstract: The method of casting of the present invention is capable of making volume of a feeder head can be small and making cooling rate of the feeder head can be easily made lower than that of a cavity. The method is executed in a casting machine, which includes a casting die, in which the feeder head is provided between a metal inlet and the cavity and in which heat insulating of the feeder head is greater than that of the cavity so as to make cooling rate of the feeder head lower than that of the cavity. The method comprises the steps of: pouring a molten metal into the cavity; reacting the molten metal on a deoxidizing compound in the cavity so as to deoxidize an oxide film formed on a surface of the molten metal; and supplementing the molten metal in the feeder head to the cavity when the molten metal in the cavity is solidified and shrinked.

Abstract: In the method of deoxidation casting, a disused metal left in a feeder head can be easily removed from a cast product, or the molten metal left in the feeder head can be removed from the cast product so as to easily finish the cast product. The method comprises the steps of: pouring a molten metal into a cavity of a casting die; and reacting a deoxidizing compound with the molten metal so as to deoxidize an oxide film formed on a surface of the molten metal. And the method is characterized in that rate of cooling the molten metal in a feeder head of the casting die is lower than that in the cavity, and that the molten metal in the feeder head, which is not solidified, is treated when the molten metal in the cavity is solidified so as to make an outline of a cast product correspond to that of a desired product.

Abstract: An apparatus and method for casting metal strip includes a moving chill body that has a quench surface. A nozzle mechanism deposits a stream of molten metal on a quenching region of the quench surface to form the strip. The nozzle mechanism has an exit portion with a nozzle orifice. A depletion mechanism includes a plurality of independently controllable gas nozzles to supply a reducing gas to multiple zones of a depletion region located adjacent to and upstream from the quenching region. The gas flow profile can be controlled in each zone independently of controlling the gas flow in other zones. The reducing gas reacts exothermically to lower the density to provide a low density reducing atmosphere within the depletion and substantially prevent formation of gas pockets in the strip.