Cast Titanium Compressor Casing.

摘要

The development of a process for centrifugally casting the Ti 6Al-4V compressor casing for the T700 turboshaft engine is described. The cast casing results in a 35-pound saving of material input and a 30-hour saving of shop labor (at the 250th unit) compared to the forging which it replaces, due to the cast net shape outer contour which includes features formerly welded to the forged casing. Conventional expendable wax patterns and ceramic shell molds were chosen over a permanent metallic mold system. Preheated molds were mounted vertically on a centrifuge and rotated at from 350 to 500 rpm during casting. Mechanical properties were well within design requirements although generally lower than forged properties. Ballistic testing showed the containment capability of the cast and forged material to be equal. Two cast casings were run in test engines and were judged to be equal in performance to forgings. There was no weight penalty associated with the use of a cast casing. (Author)