| 摘要 |
1,191,273. Altering physical structure. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. 27 June, 1967 [30 June, 1966], No. 29538/66. Heading B3V. [Also in Division C7] A metal, e.g. 20 Cr/25 Ni stainless steel tube for a nuclear fuel can, is worked to produce a varying amount of strain hardening throughout the cross-section and heat treated to produce a fine grain size, e.g. 7-12Á, at the surface and a coarser grain size, e.g. 25-50 Á, in the interior. In one embodiment, the tube wall thickness is reduced by 50% by external swaging using an internal mandrel and annealed at 800‹ C. for 80 hours or at 950‹ C. for 10 minutes, and then at 1050‹ C. for 10 minutes. In another example, the tube is internally swaged and annealed at 950‹ C. for 30 minutes. The tube may alternatively be worked by machining. |
