Abstract: A coating for a mold surface of a casting mold includes a metallic bond coat bonded to the mold surface and having a continuous, uniform thickness of between about 0.002 to 0.005 inch on the mold surface. A topcoat of yttria stabilized zirconia is located on top of the metallic bond coat and has a continuous, uniform thickness of between about 0.005 to 0.030 inch. The topcoat has a porosity between 5-15%. The topcoat has a surface layer having a thickness of between about 0.001 to 0.002 inch and a porosity of less than 1%.

Abstract: A coating for a mold surface of a casting mold includes a metallic bond coat bonded to the mold surface and having a continuous, uniform thickness of between about 0.002 to 0.005 inch on the mold surface. A topcoat of yttria stabilized zirconia is located on top of the metallic bond coat and has a continuous, uniform thickness of between about 0.005 to 0.030 inch. The topcoat has a porosity between 5-15%. The topcoat has a surface layer having a thickness of between about 0.001 to 0.002 inch and a porosity of less than 1%.

Abstract: A bottom heated holder furnace (10) for containing a supply of molten metal includes a storage vessel (20) having sidewalls (22) and a bottom wall (24) defining a molten metal receiving chamber (26). A furnace insulating layer (32) lines the molten metal receiving chamber (26). A thermally conductive heat exchanger block (50) is located at the bottom of the molten metal receiving chamber (26) for heating the supply of molten metal. The heat exchanger block (50) includes a bottom face (55), side faces (56), and a top face (57). The heat exchanger block (50) includes a plurality of electrical heaters (70) extending therein and projecting outward from at least one of the faces of the heat exchanger block (50), and further extending through the furnace insulating layer (32) and one of the sidewalls (22) of the storage vessel (20) for connection to a source of electrical power.

Abstract: A bottom heated holder furnace (10) for containing a supply of molten metal includes a storage vessel (20) having sidewalls (22) and a bottom wall (24) defining a molten metal receiving chamber (26). A furnace insulating layer (32) lines the molten metal receiving chamber (26). A thermally conductive heat exchanger block (50) is located at the bottom of the molten metal receiving chamber (26) for heating the supply of molten metal. The heat exchanger block (50) includes a bottom face (55), side faces (56), and a top face (57). The heat exchanger block (50) includes a plurality of electrical heaters (70) extending therein and projecting outward from at least one of the faces of the heat exchanger block (50), and further extending through the furnace insulating layer (32) and one of the sidewalls (22) of the storage vessel (20) for connection to a source of electrical power.

Abstract: A vacuum die-casting machine has a sprue cavity with sufficient depth facing the shot cylinder that the shot cylinder piston can easily crush with a pressure of less than 1000 psi the thin cylindrical shell of solidified metal which develops into the biscuit, and continue to advance after the die cavity becomes fried with molten metal to inject additional molten metal into the die cavity to make up for shrinkage porosity as the cast part cools. The runner through which the molten metal passes from the sprue cavity into the die cavity has generally spherical reservoirs adjacent circular gates to further assure the supply of the additional molten metal to make up for shrinkage in the part. In addition, the piston can be oil cooled steel to delay formation of the biscuit.

Abstract: Apparatus for casting a metal article includes a mold having a mold insert provided by cooperating shell and insert core which defines a coolant flow passageway. The insert has a portion disposed adjacent to the mold cavity and, in a preferred embodiment, defines a portion of the mold cavity. The passageway portion disposed adjacent to the mold defining surface of the insert has turbulence inducing elements which establish turbulence of the coolant as it flows therethrough. In a preferred embodiment, the turbulence inducing elements consist of a plurality of generally parallel elongated ribs oriented generally perpendicular to the axial extent of the turbulence inducing portion of the coolant passageway. The apparatus is particularly advantageous for a die casting having thin wall portions disposed upstream in respect of the direction of metal flow from thick wall portions. A corresponding method is provided.

Abstract: A nozzle apparatus for producing flexible fibers of superconducting material receives melted material from a crucible for containing a charge of the superconducting material. The material is melted in the crucible and falls in a stream through a bottom hole in the crucible. The stream falls through a protecting collar which maintains the stream at high temperatures. The stream is then supplied through the downwardly directed nozzle where it is subjected to a high velocity air flow which breaks the melted superconducting material into ligaments which solidify into the flexible fibers. The fibers are collected by blowing them against a porous cloth.

Abstract: A method for manufacturing a ribbed flow channel (38) results in enhancing the heat transfer performance of a hydraulically expanded heat exchanger such as a coiled tube boiler (10). The ribs are machined or rolled into a flat metal sheet (20) prior to forming a cylinder. One cylinder (28) is rolled so that the ribs are located inside the cylinder while the other cylinder (32) is rolled with the ribs located on the outside. Cylinder (32) is positioned inside cylinder (28) and electron beam welded to form a helical weld path (16). A pressure fitting (34) is attached to the welded cylinder (36) and hydraulic pressure (P) is applied to deform the cylinders (28, 32) between the helical weld path thus creating a ribbed flow channel (38).