Investment of powders and method for rapid preparation of investment molds
OwnerMashallah M. Quraishi, Anselmo J. Gutierrezinventors
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Abstract
The present invention relates to improved investment powders for use in making improved investment molds for casting metals, and the use of such molds with vacuum and/or either conventional, convection conduction or microwave heating apparatus, to rapidly eliminate water, wax and residual carbon from the mold cavities at temperatures lower than the casting temperature range of the mold at the time of casting.
Claims11
An improved investment powder for use in making molds for casting metals at a selected mold casing temperature range, said temperature range being no greater than casting temperature of the metal being cast, said powder including gypsum and, at least, one form of silica, said powder being improved by the use of at least one water soluble oxidizing agent selected from the group consisting of KNO.sub.3, Ca(NO.sub.3).sub.2, LiNO.sub.3, Fe (NO.sub.3).sub.2, NaNO.sub.2, Ni(NO.sub.3).sub.2, Cu(NO.sub.3).sub.2, Al(NO.sub.3).sub.2, NH.sub.4 NO.sub.3 and Mg (NO.sub.3).sub.2 and present at 1/2-10% of said powder, where, when heated, said oxidizing agent releases oxygen at temperatures below said selected mold casting temperature range and said release of oxygen allows elimination of water wax and residual carbon present in said mold at said temperature range.
An improved investment powder for use in making molds for casting metals, said powder including gypsum, and, at least, one form of silica, said powder being improved by the use of 0.1-10% glucose, wherein said glucose decomposes to carbon below a selected mold casting temperature range, said temperature range being no greater than the casting temperature of the metal being cast, wherein said decomposition renders said molds more susceptible to heat radiation.
Dependencies are inferred from the claim text.