| 摘要 |
PURPOSE:To obtain high degree of resistance for the increasing permeability even when there is deformation and its repetition in the material used at a cryogenic temperature by a method wherein a prestrain is statically given to austenite stainless steel within the range in which magnetic permeability is not increased at room temperature. CONSTITUTION:A prestrain is statically given to austenite stainless steel at room temperature within the range in which permeability does not increase. To be more precise, a work-hardening process is performed statically on the above-mentioned stainless steel at the room temperature, which is insensitive to the change in permeability, within the range wherein magnetic permeability is not increased. Tension is not necessarily required, the same result can be obtained by giving a compressive strain, and pertaining to a practical hardening method, the hardening of the stainless steel can also be accomplished by cold rolling and the like performed in the stage of manufacture of the material. By increasing the strength of material at a cryogenic temperature by work- hardening the material as above-mentioned, the range of distortion of permeability boosting limit can be effectively increased. |
