Howmet Research Corporation

Howmet Corporation

John R Brinegar

Mark L Soderstrom

Dennis J Thompson

Bart M Kilinski

Brad J Murphy

Bradley Donaldson

William J DePue

Keith R Chamberlain

James J Vresics

Apparatus and method for DS casting using one or more thermal baffle members positionable at a lower open end of a directional solidification casting furnace by movement of a ram on which a mold to be cast is moved relative to the casting furnace. A unique thermal baffle member can be used for each particular series or run of molds to be cast.

Directional solidification method and apparatus

Molten metallic material is cast into a mold that is made with a barrier to reduce gas permeability through a mold wall that forms on its innermost side a mold surface for contacting the molten metallic material. The molten metallic material is gravity cast into the mold residing in a furnace in a casting chamber under a first pressure, such as subambient pressure. Then, a gaseous pressure is provided in the casting chamber higher than the first pressure rapidly enough to reduce or eliminate the presence of localized voids in the casting solidified in the mold.

Investment casting with improved melt filling

Method as well as apparatus for DS casting using a multi-stage thermal baffle disposed proximate a lower end of a DS casting furnace. The thermal baffle comprises a fixed primary baffle disposed at the lower end of the casting furnace and a secondary baffle initially releasably disposed adjacent and below the primary baffle prior to withdrawal of the melt-filled mold from the casting furnace. The primary baffle includes a primary aperture oriented perpendicular to the mold withdrawal direction and having a cross-sectional configuration tailored to accommodate a relatively large exterior region or profile of the melt-filled mold, such as a relatively wide platform region of a mold for making a turbine blade or vane. The secondary baffle includes a secondary aperture also oriented perpendicular to the mold withdrawal direction and having a cross-sectional configuration tailored to accommodate a relatively smaller exterior region or profile of the melt-filled mold, such as a narrower airfoil region of a mold for making a turbine blade or vane. The secondary baffle remains adjacent and immediately below the primary baffle during withdrawal of the mold from the furnace until the relatively larger region of the melt-filled mold passes through the primary aperture in a manner to release or disengage the secondary baffle from a temporary baffle support means to allow the secondary baffle to drop or move downwardly onto the chill plate for continued movement therewith as the melt-filled mold continues to be withdrawn from the furnace.

Method and investment shell mold for casting comprising introducing molten metallic material into an investment shell mold to fill a mold cavity and provide an upper surface of the molten metallic material above the mold cavity. An initially closed, destructible region of the mold then is broken to provide an entry opening through which exothermic material is placed on the upper surface of the molten metallic material to provide a source of molten metallic material to accommodate shrinkage of a casting as it solidifies in the mold cavity.

Investment casting with exothermic material

Method and apparatus for directional solidification of molten metal using a general horizontally oriented mold initially positioned in a casting furnace. The mold is filled with molten metal through a mold pour cup located on an upper region of the mold and a pour cup runner that enters the mold at location proximate a grain selection passage. The melt filled mold initially is withdrawn from the casting furnace to solidify the molten metal at the location where the pour cup runner enters the mold. The melt filled mold then is withdrawn while the mold is rotated about its horizontal axis to reduce segregation of alloying elements in the solidifying molten metal. Initial solidification of molten metal at the entry of the pour cup runner to the mold prevents molten metal from flowing out of the mold through the pour cup when the mold is subsequently rotated.

Horizontal rotating directional solidification

Method and apparatus for directional solidification of molten metal employs a generally horizontally oriented mold initially positioned in a casting furnace. The mold residing on a chill is filled with molten metal through a mold pour cup located on an upper region of the mold. The mold is withdrawn from the casting furnace to effect directional solidification. As the molten metal filled mold is withdrawn, the mold is oscillated about a general horizontal axis within an angular range of up to about 180 degrees. Such limited angle oscillation during mold withdrawal reduces segregation of alloying elements in the solidifying molten metal and prevents molten metal from leaving the mold through the pour cup.

Horizontal directional solidification

A method of forming a fine grained equiaxed casting by melting metal and removing most of the superheat of the molten metal. The molten metal is placed in a mold and optionally subjected to turbulence whereupon it solidifies to form the casting of the desired microstructure.

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Muskegon, MI, United States of America

John R Brinegar