Patent ID: 7687021
Filing Date: 2010-03-30
Classification: B22F,F01D,F05D,Y02T,Y10T

Abstract:
1. A method of fabricating a turbine stator casing, said casing comprising a double-skinned shroud with inner and outer skins and empty spaces between the inner and outer skins, the method comprising: between walls of portions of a mold comprising at least two portions, forming a cavity of shape corresponding to that of said shroud; securing cores made of soluble material to at least one of said mold portions with tubular pegs, said cores being held spaced apart from the wall of said mold portion by said pegs and representing said empty spaces that are to be provided inside said shroud, each peg having a first end and a second end, said first end being mounted in a first housing formed in one of said cores and said second end being mounted in a second housing formed in the mold portion, and wherein each peg defines a through hole opening out through its first and second ends, filling said cavity with a metal alloy powder such that said pegs are in contact with said powder; sintering said powder by hot isostatic pressing such that said powder densifies to form said shroud during said sintering and such that said pegs are welded to said outer skin of said shroud during said sintering; eliminating said cores by dissolving said cores with a solvent that does not dissolve said pegs such that said first end of each peg is located in said empty spaces between the inner and outer skins of the shroud; and extracting the shroud from said mold with the second end of each peg protruding from said outer skin of said shroud such that said through hole of each peg provides a cooling air passage from outside said shroud, through said outer skin of the shroud and into paid empty spaces between the inner and outer skins of the shroud.