| 摘要 |
<p>1472939 Casting processes; forging; making gear and like blanks OSPREY METALS Ltd 19 Aug 1975 [21 Aug 1974] 36770/74 Headings B3F B3A and B3H A method of manufacturing a spray deposited preform of metal or metal alloy from which a precision metal article can be manufactured comprises directing a stream 6 of molten metal or metal alloy on to a collecting surface 7, atomizing the stream by subjecting it to high velocity jets of gas 4 having an initial temperature that is appreciably less than that of the molten metal or alloy, the gas temperature and flow rate being such that sufficient heat is extracted by the gas from the molten metal or alloy during flight and on deposition on the surface that the molten metal or alloy forms a coherent preform and its solidification and formation are not dependent on the temperature and/or thermal properties of the collecting surface. In apparatus for carrying out the method, molten metal 1 is poured through a refractory nozzle 3 of a tundish 2 and is atomized and cooled by jets of nitrogen, argon, or a mixture of carbon monoxide, carbon dioxide, nitrogen and hydrogen at ambient temperature discharged from an atomizing device 4. The spray 6 of hot particles is deposited on the collecting surface or die 7 to form the preform 8 which may be removed by an ejector 9. The preform may be transferred directly or at some later stage to the dies 10, 11 of a drop-forging hammer to produce a forging with or without the addition of heat, surplus flash being trimmed off to produce the precision article such as a gear, lever, cutting tool, impeller blade, rocker arm, &c. The precision article may be formed by pressing or extrusion. More than one spray may be used acting simultaneously or consecutively and relative movement may be effected between the spray and collecting surface. The metal or alloy may be carbon or alloy steels, aluminium, aluminium alloys, brass, phosphor bronze, nickel or cobalt based alloy. The article may comprise a mixture of materials which are mixed in flight or sprayed so that the article is formed of layers of different material. Fibres, filaments or whiskers may be incorporated in the sprayed material.</p> |
