GB897133A - Improvements in or relating to methods for producing blades for fluid flow apparatus - Google Patents

Abstract

897,133. Making turbine blades; bending and twisting; extruding; forging; die-rolling. GENERAL ELECTRIC CO. May 26, 1959 [May 28, 1958; Oct. 9, 1958], No. 17888/59. Classes 83 (2) and 83 (4). A process for making a turbine or like blade from a blank 10, Fig. 2, having a base 10b and an airfoil section 10a joined together by a transition section 10t comprises reducing the latter at 10r, Fig. 6, by flowing metal away therefrom to form fillets 10# on opposite sides of the blank and to shape the adjacent surface 10s of the base; rolling the airfoil section 10a between opposed rolling dies 44, 45, Fig. 17; upsetting the base surface 10s and fillets 10# and simultaneously coining the blank between dies 120, 121, Fig. 28, to finish forge the airfoil section 10a with the desired cant and twist; finally trimming the airfoil section to finished dimensions. Extruding.-A heated slug of rectangular section, Fig. 1 (not shown), is extruded in a die 12, Fig. 2, by a ram 11 to form the airfoil section 10a and transition section 10t. Upsetting; die rolling.- After cleaning, the blank 10, Fig. 7, is placed between dies 25, 26 pivoted respectively at 27, 28, and pressed by a mechanical or hydraulic ram 16. Protuberances 14a, 15a, Fig. 6, thus form the rounded fillets 10# whilst the base 10b is upset to fill the cavity 32; excess metal forms a flash 10m. Downward movement of dies 25, 26 is limited by stops 33, 34 and upward movement, performed by springs 35, 36, is limited by adjustable stops 39, 40. An ejector 38 actuated by spring or piston means 37 assists removal of the blank. The flash 10m is then removed and, preferably after cleaning and annealing, the blank is inserted in the holder 42, Fig. 17, of a die-rolling apparatus where the airfoil 10a is rolled between die rolls 44, 45. Lower roll 45, Fig. 19, is mounted on a stationary axis whilst upper roll 44 is carried by an arm 72a pivoted at 73 and actuated by a mechanical or hydraulic ram 78. Holder 42 is carried by a member 90 slidable along horizontal guides 95 by a piston 88 and held initially in an inclined position by a lug 92 engaging a fixed pin 91. Thus after inserting the blank in holder 42, hydraulic fluid supplied from reservoir 80 by pump 81 is admitted through solenoid valve 87b to the right of piston 88 which moves member 90 leftwise, and causes it to fall against plunger 99. Meanwhile, arm 72a has been lowered by ram 78 to grip the blade between the rolls 44, 45 and subsequently a member 104 engages a pivoted lever 101 to urge the entire holding assembly 96 leftwise against spring 103 with a force sufficient to reshape the fillets 10# and surface 10s, Fig. 15 (not shown). Switch 113 actuated by the arm 72a then reverses solenoid valve 87a, causing hydraulic fluid to act on the right of piston 69 which rotates the die rolls anticlockwise through linkage 67, 65, 76, 74, 63, 61; simultaneously, valve 87b is also reversed whereby air pressure from receiver 89 acting continuously on the left of piston 88 produces a biasing force 51, Fig. 17, on the blade to keep it straight during rolling. Forging; bending and twisting.-The blank 53 is then placed between coining dies 120, 121, Fig. 28, with its base 10b resting against spring-loaded anvils 122a, 122b. Top die 120 is then lowered, for example by a toggle press, whereby inclined surfaces 124a, 122s cooperate to force the blank between the dies and upset its surface 10s against die surfaces 120a, 121a, and reshape the fillets. Meanwhile the airfoil section 10a has been bent upwardly relativley to its base and as the dies close this section is coined and twisted. A locating hole is also punched by a pin 137. Finally, the airfoil section is trimmed in length and width, the leading and trailing edges are rounded and the base 10b machined. Specifications 897,135, 897,136 and 897,137 are referred to.