GB820035A - Improvements relating to turbine or compressor blades - Google Patents

Abstract

820,035. Making turbine and like blades; extruding. WIGGIN & CO. Ltd., H. Oct. 18, 1957 [Oct. 23, 1956], No. 32306/56. Classes 83 (2) and 83 (4). A method of making a turbine or compressor blade having a blade portion 4, Fig. 7, with an integral root 8 and platform 9 and having longitudinal cooling passages 2, comprises making holes longitudinally in a billet, Figs. 2, 8 (not shown), and filling them with a removable filler having similar flow characteristics to the billet metal, partially extruding the billet through a die 15, Fig. 3, to produce a blank having an extruded portion 4 for forming the blade and an unextruded portion 5, in which parts 6 of the holes are inclined, for forming the root and platform, and machining the root and platform whereby the inclined parts of the holes are intersected by a machined surface or surfaces and open at 10 in one or both sides of the root. The billet may be of a creep-resisting nickel chromium or nickel-chromium-cobalt alloy and the filler of an iron-manganese-titanium alloy. Blind holes are drilled in the billet and after filling, the solid end thereof is hot-extruded through the die 15 which has inclined surfaces 17 determining the inclination of the parts 6. Opposite sides 20, Fig. 5 (not shown), of the root are then curved by machining or gap rolling and the blank portion is hot forged in closed dies to aerofoil section, Fig. 6 (not shown). The root and platform are then machined. The solid end of the blade portion may be cut off to expose the holes or a shroud may be formed by upsetting the solid end and drilling holes therein to meet the passages 2. In another embodiment, Figs. 8-10 (not shown), only one row of holes are drilled in the billet to form passages which open into one side only of the blade root. The filler is removed by acid leaching or otherwise.