| 摘要 |
1,221,538. Extruding; working at specified temperatures; making typewriter parts. INTERNATIONAL BUSINESS MACHINES CORP. 24 May, 1968 [14 July, 1967], No. 24853/68. Headings B3A, B3P and B3V. [Also in Division C7] A method of forming a metal article particularly a typewriter part comprises pressing metal from a heated stock 20 through a passageway 15 and into a heated forming cavity 11, the pressure causing the metal to be passed into the cavity as a ribbon which is then deformed by bending and pressed into a solid body having a shape conforming to that of the internal surface of the cavity, the metal being maintained wholly in a solid crystalline phase throughout the process. The stock metal and forming cavity are preferably heated such that the metal used attains a temperature at which it becomes superplastic. Metal pellets may also be used in the process. Preferred metals are by weight 78% zinc and 22% aluminium; 67% aluminium and 33% copper; 88% aluminium and 12% silicon; or 62% copper and 38% zinc; 59% copper and 41% zinc or 52% copper and 48% zinc. Preferred forming temperatures for the Zn: Al alloy are 500‹ to 532‹ F. and for the Al : Si alloy 900‹ to 1040‹ F. |
