Howmet Research Corporation

Howmet Corporation

Rajeev V Naik

John J Corrigan

Brian David Przeslawski

A casting furnace includes a melting chamber, a dual zone mold heating chamber, and a dual zone mold cooling chamber. The melting chamber provides a source of molten alloy or ceramics with adequate superheat. The dual zone mold heating chamber includes an independently controlled primary heating zone and a secondary heating zone. The primary heating zone raises the mold temperature adequately to impart high gradient solidification conditions. The secondary heating zone assists the primary heating zone to minimize overheating of the majority of the mold. The dual zone mold cooling chamber includes a primary cooling chamber and a secondary cooling chamber. The primary cooling chamber speeds up solidification in order to prevent defect formation and refine microstructure. The secondary cooling chamber slows down the cooling of castings to reduce residual stresses build up and minimize elemental segregation through augmenting solid-state diffusion of lower melting elements.

Casting furnace for solidification restructuring (FSR)

A casting method and apparatus are provided for casting a near-net shape article, such as for example a gas turbine engine blade or vane having a variable cross-section along its length. A molten metallic melt is provided in a heated mold having an article-shaped mold cavity with a shape corresponding to that of the article to be cast. The melt-containing mold and mold heating furnace are relatively moved to withdraw the melt-containing mold from the furnace through an active cooling zone where cooling gas is directed against the exterior of the mold to actively extract heat. At least one of the mold withdrawal rate, the cooling gas mass flow rate, and mold temperature are adjusted at the active cooling zone as the melt-containing mold is withdrawn through the active cooling zone to produce an equiaxed grain microstructure along at least a part of the length of the article.

Casting method, apparatus and product

Casting method, apparatus, and product

Method and apparatus for casting molten metal or alloy into a plurality of molds that are connected by mold ingate passages in melt flow communication to a melt supply passage which is configured in a manner to completely or partially fill the molds with the molten metal or alloy sequentially one after another. Filling of the molds in this manner provides uniform mold filling, reduces foreign matter in molds filled after the first-filled mold, and improves quality of the cast articles.

Sequential mold filling

A ceramic investment shell mold is reinforced with a carbon based fibrous reinforcement having an extremely high tensile strength that increases as the mold temperature is increased especially within the range of casting temperatures employed for casting large directionally solidified industrial gas turbine components. The carbon based fibrous reinforcement is wrapped or otherwise positioned around the repeating ceramic slurry/stucco layers forming the intermediate thickness of the shell mold wall. The reinforced shell mold can be used to cast large directionally solidified industrial gas turbine components with accurate dimensional control.

Reinforced ceramic shell mold and method of making same

A reinforced core for use in metal casting processes, especially directional solidification casting processes, comprises an elongated, thin-walled outer quartz or silica rich tubular member and a carbon base reinforcement disposed in and extending along a length of the tubular member. The carbon base reinforcement can comprise one or more graphite rods cemented together in end-to-end relation or a carbon fiber bundle. The carbon base reinforcement can include an outer carbide surface region by coating or surface reaction.

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Grafton, VA, United States of America

Rajeev V Naik