Abstract:
A single-crystal seed, apparatus and process for producing a casting having a single-crystal (SX) microstructure. The seed has a geometry that includes a vertex capable of destabilizing an oxide film that forms at the interface between the seed and a molten metal during the casting process, and thereby promotes a continuous single-crystal grain growth and reduces grain misorientation defects that can initiate from the seed/metal interface.
Abstract:
A single-crystal seed, apparatus and process for producing a casting having a single-crystal (SX) microstructure. The seed has a geometry that includes a vertex capable of destabilizing an oxide film that forms at the interface between the seed and a molten metal during the casting process, and thereby promotes a continuous single-crystal grain growth and reduces grain misorientation defects that can initiate from the seed/metal interface.
Abstract:
A cast article of a ductile iron wherein the ductile iron includes carbon from about 2.8 to 3.7 w/o, silicon from about 3.0 to 3.5 w/o, molybdenum from 0.8 to 1.5 w/o, magnesium from about 0.025 to 0.60 w/o, sulfur less than 0.01 w/o and nickel from about 0.0 to 1.3 w/o, the remaining content being iron is provided. The cast article is suitable for a gas turbine casing. A method of manufacturing a cast article is also provided.
Abstract:
A single-crystal seed, apparatus and process for producing a casting having a single-crystal (SX) microstructure. The seed has a geometry that includes a vertex capable of destabilizing an oxide film that forms at the interface between the seed and a molten metal during the casting process, and thereby promotes a continuous single-crystal grain growth and reduces grain misorientation defects that can initiate from the seed/metal interface.
Abstract:
A component for wind turbines includes cast austempered ductile iron containing about 3.0 to about 3.8 weight percent carbon, about 1.9 to about 2.8 weight percent silicon, up to about 0.3 weight percent manganese, up to about 0.8 weight percent copper, up to about 2.0 weight percent nickel, up to about 0.3 weight percent molybdenum, about 0.03 to about 0.06 weight percent magnesium, less than about 0.05 weight percent chromium, less than about 0.02 weight percent vanadium, and less than about 0.01 weight percent sulfur. The component is preferably a drive shaft or gearbox component having a mass of more than about 3 tons. A method of manufacturing the component is also provided.
Abstract:
A method by which properties of a component (18) formed of a ductile iron alloy and having thick sections can be promoted with an austempering process. The method entails casting a ductile iron alloy containing iron, carbon, silicon and alloying constituents. The casting is solidified at a rate that inhibits segregation of the alloying constituents to grain boundaries of the casting, and so that the casting contains graphite nodules having a count of greater than 100 nodules per mm2. The casting is then austempered by heating to an austenitization temperature to yield a microstructure having a single-phase matrix of austenite that contains carbon, and then quenching the casting to an austempering temperature. The casting is held at the austempering temperature for a duration sufficient to yield a microstructure whose matrix is mostly ausferrite and essentially free of martensite and pearlite.
Abstract:
A nickel base superalloy suitable for the production of a large, crack-free nickel-base superalloy gas turbine bucket suitable for use in a large land-based utility gas turbine engine, comprising, by weight percents: Chromium 7.0 to 12.0 Carbon 0.06 to 0.10 Cobalt 5.0 to 15.0 Titanium 3.0 to 5.0 Aluminum 3.0 to 5.0 Tungsten 3.0 to 12.0 Molybdenum 1.0 to 5.0 Boron 0.0080 to 0.01 Rhenium 0 to 10.0 Tantalum 2.0 to 6.0 Columbium 0 to 2.0 Vanadium 0 to 3.0 Hafnium 0 to 2.0 and remainder nickel and incidental impurities.