| 摘要 |
1,251,488. Forming metal; working at specified temperatures. PRESSED STEEL FISHER Ltd. 22 Aug., 1970, No. 40556/70. Headings B3Q and B3V. Apparatus for forming a superplastic alloy sheet 26 against a die 12 in an enclosure 11 having blank holding means 25 comprises a reservoir 14 containing a forming material 15 which is liquid at least at the forming temperature, a heater 29 for the material 15, a gas pressure supply 18 for expelling material from the reservoir into the enclosure 11, an overflow 20 for returning excess material 15 to the reservoir and a valve 19 for releasing gas pressure and allowing material 15 to flow back from the enclosure 11 to the reservoir. Thus after heating the sheet to the forming temperature, a partial vacuum set up by gravity-return of the material 15, which may be a low-melting-point alloy, oil or a salt, draws the sheet against the die. The forming action may be assisted by compressed-air supplied to a cover 27. Automatic blank loading, stripping and unloading devices may be provided and an air jet for cooling the work. |
