Cast turbine casing and nozzle diaphragm preforms

摘要

Various turbine component preforms are disclosed having near-net shape features. In one embodiment, a turbine casing preform is disclosed. The turbine casing preform includes an as-cast body comprising a partially cylindrical wall section of a turbine casing, the wall section having an inner surface and an outer surface. The turbine casing preform also includes a circumferentially-extending vane slot formed in the wall section on the inner surface. In another embodiment, a turbine nozzle diaphragm preform is disclosed. The turbine nozzle diaphragm preform includes an as-cast body comprising a partially-cylindrical wall section of a turbine nozzle diaphragm having an inner surface and an outer surface. The turbine nozzle diaphragm preform also includes an as-cast, circumferentially-extending seal member projecting from one of the outer surface or inner surface.

主权项

1. A turbine casing preform, comprising:
an as-cast body comprising a partially cylindrical wall section of a turbine casing, the wall section having an inner surface and an outer surface, the as-cast body comprising a nodular cast iron; and an as-cast vane slot formed in the wall section on the inner surface, the inner surface proximate the as-cast vane slot comprising a fine grain size as-cast microstructure having an average graphite nodule count of 100/mm2 or less, the as-cast vane slot having an as-cast slot profile that is configured for removal of the nodular cast iron to a depth sufficient to form a final vane slot having a final slot profile and a microstructure proximate the final vane slot that is substantially the same as the as-cast microstructure.