Abstract:
In manufacturing blades for gas turbines with a plurality of inner cooling channels by isostatic compression, a sintering capsule of deformable material is provided with thin-walled tubes arranged substantially parallel to the capsule wall parts corresponding to the high and low pressure surfaces of the blade. A powdered material is poured into the capsule, which is then evacuated, sealed and heated to at least 800*C. Thereafter the heated capsule is subjected to an external gas pressure of at least 500 bars. Simultaneously with the compression, the tubes are subjected to such a high internal gas pressure that the linear decrease in the tube cross-section is at most 50 percent.
Abstract:
FOR MANUFACTURING BILLETS OUT OF POWDER FOR FURTHER MACHINING BY ROLLING, FORGING OR MCAHINING, POWER IS POURED INTO A CONTAINER HAVING AN EVAUCATING OPENING AND IS THEN ISOSTATICALLY COMPRESSED BY SUBJECTING THE CONTAINER WITH THE ENCLOSED POWER TO A HIGH EXTREME PRESSURE. THE BILLET IS PLACED IN A HEATED FURNACE AND HEATED WHILE IT IS SIMULTANEOUSLY EVACUATED FOR DEGASSING. AFTER EVACUATION IS COMPLETED, THE BILLET IS PREHEATED IN ANOTHER FURNACE TO A TEMPERATURE SUITABLE FOR PRESSURE SINTERING AND THEN IN ANOTHER FURNACE IS SUBJECTED SIMULTANEOUSLY TO HIGH HEAT AND HIGH PRESSURE.
Abstract:
In a procedure in which a body formed of an iron-based alloy is manufactured from powder by isostatic compression, the powder is placed in a flexible container and subjected to isostatic pressure and heat. The isostatic hot pressing is carried out at two temperatures, at one of which the iron-based alloy is at least 25 percent in Alpha -phase and at the other of which the iron-based alloy is in gamma -phase. If the treatment at the temperature for gamma -phase is carried out first, the body is cooled below the temperature level at which it is at least 25 percent in Alpha -phase to prevent retention of the gamma phase and then raised to the temperature at which it is at least 25 percent in Alpha -phase.
Abstract:
In a cylindrical elongated furnace for treating material at high temperature in a gaseous atmosphere under high pressure, the furnace chamber is insulated from the walls of the pressure chamber by at least three tubular parts arranged one inside the other with insulating parts. At least one ring is provided attached to one of the tubular parts and having a downwardly and inwardly sloping similar part secured to the inside of this part and directed towards, but terminating short of, the opposed part.
Abstract:
A cylindrical elongated furnace for treating material at high temperature in a gaseous atmosphere under high pressure is formed of a high pressure cylinder with end closures projecting into it and a furnace chamber arranged in the high pressure cylinder. The furnace chamber is insulated from the walls of the pressure chamber by a cylindrical casing having gas-impermeable tubes arranged one inside the other with an insulation between them. At least one layer of insulating material in the casing engages only the outer or inner surface of one tube and is spaced from the adjoining tube, the space between being filled with gas. The insulating material may be held against the outside of one of the tubes by rings or a spiral strip running helically.
Abstract:
Sintered bodies are formed from powder material by sintering a body produced from a powder at atmospheric pressure or below and at such a temperature that the powder grains adhere to each other and thereafter isostatically hot pressing the sintered bodies to high density in a furnace containing an inert atmosphere. The powder may contain hard metal particles such as metal carbides and a binder of an iron group metal. The furnace is formed by a cylindrical pressure chamber with a high pressure cylinder and end closures projecting into the cylinder. A furnace chamber is arranged in the pressure chamber and has heating windings and an insulating lid and bottom. One end closure of the pressure chamber has an annular part with members sealing against the cylinder and a valve plate covering the opening of the annular part. A vacuum conduit is provided which can be sealingly connected to the annular part and which includes projecting members for separating the valve plate and the annular part when the conduit is placed in operative position.