GB830472A - Improvements relating to the production of turbine or compressor blades - Google Patents

Abstract

830,472. Making turbine and like blades; extruding. WIGGIN & CO. Ltd., H. Jan. 21, 1958 [Jan. 21, 1957], No. 2153/57. Classes 83 (2) and 83 (4). A turbine or compressor blade having an integral root and longitudinal cooling passages is made by forming a billet, Fig. 3, with longitudinal holes of greater cross-sectional area over part of their length 2, than over the remainder 2<SP>1</SP>, inserting a filler into the holes, deforming some or all of that part of the billet with a greater size hole to form a blank for the blade portion, and then removing the filler. The holes may be drilled from one or from opposite ends of the starting billet using different diameter drills, Fig. 6 (not shown). In another embodiment a starting billet 1, Fig. 1 (not shown) has longitudinal holes 2 of uniform diameter drilled wholly or partly therethrough. The holes may then be deformed into elliptical section, Fig. 5 (not shown), by rolling the billet as described in Specification 826,152. The billet is then partially extruded from a container 3, Fig. 2, through a die of rectangular section 5, by means of a ram 4, whereby the filled holes 2<SP>1</SP> in the extruded part are reduced in size. The unextruded part of the billet is then machined to provide a billet of uniform section, Fig. 3, and this billet is partially extruded by a ram 7, Fig. 4, from a container 6 through a die 8 of roughly aerofoil section to form the blade portion. Alternatively the blade portion may be formed by rolling. The blade portion with its fitted holes 2<SP>11</SP> is then formed into its final profile by rolling, die-stamping or machining. In another embodiment the starting billet 13, Fig. 7, is cut from a bar 12 of T-section. Holes 14 of uniform section are drilled and the head portion of the billet is then extruded by means of a ram 16, Fig. 9, through a die 17 whose orifice has a cross-section substantially the same as the leg portion 13 of the billet which leads during the extrusion. The holes 14<SP>1</SP> in the extruded head portion are thus reduced. The resultant billet, after trimming off at X-X, is then partially extruded through the die 8, Fig. 4. The leg 13 may be tapered so as to produce tapered cooling passages in the final blade. When a shroud is required at the tip end the holes are blind at the leading end of the billet and the blind end is subsequently deformed to the shape of the shroud.