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US 4,287,932 AGranted
Process for the precision molding of castings
AssigneeSulzer Brothers Limited
InventorHans Schneider
Life of this patent
Estimating the term…
Abstract
The material used for the production of cores for precision molds is a metal which is oxidizable at relatively low temperatures, i.e., below the solidification temperature of the melts for pouring, and which passes directly from the solid state to the gas state by oxide sublimation. This greatly speeds up the dissolving of cores, particularly small diameter cores, out of the castings.
Claims11
A process for the precision molding of castings, said process comprising the steps of
- forming a lost pattern with at least one inserted core of a metal which is oxidizable below the solidification temperature of a melt to be cast;
- thereafter forming a ceramic mold about said pattern and core;
- dissolving the pattern out of the ceramic mold;
- thereafter firing and heating the ceramic mold to a predetermined temperature;
- and
- pouring a melt of molten metal into the ceramic mold, whereby after solidification of the melt into a casting, the core metal oxidizes and sublimates to escape out of the casting.
3 more elements
A process of precision casting a turbine blade comprising the steps of
- positioning a plurality of metal cores in a chill mold, said cores being oxidizable below the solidification temperature of a melt to be cast;
- die-casting a lost pattern in the chill mold with said cores therein;
- forming a ceramic mold about the pattern and cores;
- dissolving the pattern out of the ceramic mold;
- then heating and firing the ceramic mold at a temperature of about 1000.degree. C. in the absence of air;
- pouring a melt of casting material into the heated ceramic mold;
- and
- thereafter exposing the ceramic mold to air to permit oxidization of the cores and sublimation of the cores out of the casting material during cooling of the casting material into a casting.
5 more elements
A process for precision casting a turbine blade comprising the steps of
- positioning a plurality of molybdenum wires with a coating of ceramic material thereon in a chill mold;
- die-casting a lost pattern in the chill mold with said wires therein;
- forming a ceramic mold about the pattern and wires;
- dissolving the pattern out of the ceramic mold;
- then heating and firing the ceramic mold at a temperature of about 1200.degree. C. in the absence of air;
- pouring a melt of casting material at a temperature of about 1500.degree. C. to 1600.degree. C. into the heated ceramic mold;
- and
- thereafter exposing the ceramic mold to air to permit oxidization of the wires and sublimation of the wires out of the casting during cooling of the casting material into a casting.
5 more elements
Dependencies are inferred from the claim text.