| 摘要 |
<p>PURPOSE:To eliminate incorrect inward curved deformation at a cylindrical part and relieve the internal stress in a reverse curved part by a method wherein a vessel, in the interior of which vacuum is generated by cooling, is set in a vacuum chamber and a bottom part is inward deformed by reversely depressing by pressing the lower end part of the bottom part with a pressing jig and finally the vessel is heated for heat setting. CONSTITUTION:A vessel 1 in which high temperature containment liquid is hermetically contained is housed and arranged upside down in a vacuum chamber 7. In this case, since the degree of vacuum in the vacuum chamber 7 is too small to allow to develop curved deformation at a cylindrical part 2, the vessel 1 is positioned in the vacuum chamber 7 with no curved deformation developed. In the state just mentioned above, a reverse depressed deformation is smoothly carried out by pressing the lower end part of the bottom part 3 with a pressing jig 8. Next, by pressingly heating the reverse curved part with a heating plate 10, a heat setting treatment to relieve the internal stress, which is generated within the reverse curved part, is done so as to stabilize the reverse curved form of the reverse curved part in order to allow to give a high self-form-retaining capability to the lower end part of the bottom part 3.</p> |
