GB784124A - - Google Patents

Abstract

784,124. Moulding metal powders. BIRMINGHAM SMALL ARMS CO., Ltd. May 27, 1955 [June 8, 1954], No. 16704/54. Class 87(2). [Also in Groups II and XXVI] A gas turbine blade or other article, having ducts therein, is made from metal powder by making a metal powder compact having therein destructible cores, and then heating the compact to sinter the metal particles together and drive off the core material as gas, the spaces previously occupied by the cores constituting ducts. The cores are made of non-metallic material that is hard but resilient at normal temperature, e.g. polystyrene or hard wax. Figs. 1 to 4 illustrate a method of forming a gas turbine blade compact in which first, Fig. 1, metal powder 1 is filled into a die 2, levelled and lightly (100 p.s.i.) compacted by a punch 3 having nine groove-forming ribs 6. This number nine is equal to the number of ducts to be formed in the blade. Into one of the grooves 5 so formed in the surface of the powder is placed a polystyrene &c. core 7, Fig. 2. Then a second layer 10 of powder is placed on top of the first layer, levelled and lightly compacted, and into two of the grooves thus formed are placed two cores 12, Fig. 3. These operations are repeated until all nine groove positions have been filled with cores, as shown in Fig. 3, the last core being shown at 14. A plain punch 15 then applies high pressure (10-30 tons p.s.i.) and compresses the powder to a compact 9, Fig. 4, which is in shape a rectangular parallelepiped, the cores taking up the positions shown. The compact 9 is then sintered, the cores passing off as gas to leave ducts. The sintered compact is machined to form a gas turbine blade shown in outline at 16, Fig. 4, and in Fig. 5. In Fig. 5, 20 are the ducts and 22 are (machined) channels for the supply of cooling fluid to the ducts. The ducts may be other than circular in cross-section, may have bulbous closed ends, and may be branched. Specification 784,123 is referred to.