Pcc Structurals, Inc.

Michael Gerald Sorbel

David H Sturgis

Mehrdad Yasrebi

Karl Milton Taft, Iii

Douglas Gene Nikolas

Mark E Springgate

Embodiments of a method for increasing the lifetime of a casting slurry are described. One feature of the disclosed embodiments comprises processing refractory materials that are used to form casting slurries to provide a substantial increase in slurry lifetime for slurries made using such processed materials compared to slurries made using materials not processed as described herein. One embodiment of the method comprises heat processing at least one refractory powder. Without limiting the invention to a theory of operation, processing is continued for a period of time sufficient to reduce the amount of hydration from a first hydration level to a second hydration level. A slurry is formed using the refractory powder at a hydration level which provides an increased slurry lifetime relative to the same material without processing according to the disclosed embodiments.

Method for processing casting materials to increase slurry lifetime

Methods for increasing the lifetime of a casting slurry are described. One feature of the invention is processing refractory powders at a first hydration level to produce powders having a second, lower hydration level before the processed materials are used to form casting slurries. Processing according to the disclosed methods results in a substantial increase in the lifetime of a slurry made using such processed materials compared to slurries made using materials not processed as described herein. One embodiment of the method comprises heat processing at least one refractory powder, typically refractory powders which have undergone hydration subsequent to commercial production, for a period of time sufficient to reduce the amount of hydration from a first hydration level to a second hydration level. A slurry is formed using the refractory powder at an hydration level which provides an increased slurry lifetime relative to the same material without processing according to the method of the present invention. Slurry formation can be accomplished substantially immediately after processing, or up to about one week after processing, typically less than 24 hours after processing, and even more typically within 2 hours to about 8 hours after processing.

Method for processing materials to increase slurry lifetime

Wax compositions that are useful, amongst other things, for forming investment casting patterns are described. One embodiment of the wax composition comprises: (a) pattern wax; and (b) from about 1% to about 85% by weight of a polymeric organic carbonate filler material. Examples of particular polymeric organic carbonate filler materials include, without limitation, polyethylene carbonate, polypropylene carbonate, poly(cyclohexane carbonate), poly(cyclohexane propylene carbonate), and mixtures thereof. Crosslinking the organic portion of the polymeric organic carbonate filler material can substantially reduce its thermal expansion. The wax compositions generally include other materials commonly used to form wax compositions. Such materials include waxes and resinous materials, conventional fillers, ultra-violet curable monomers, plasticizers, lubricants, and mixtures thereof. Conventional fillers, including urea, can be copolymerized with the polymeric organic carbonate filler material to reduce the dissolution and/or agglomeration of the filler. Wax patterns useful for forming investment casting molds are then made from such compositions using conventional techniques, such as injection molding. The patterns are serially immersed in slurries comprising refractory materials to form casting molds. Metal and metal alloy articles are then cast using such molds.

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Oregon City, OR, United States of America

Michael Gerald Sorbel