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A device has a magnetically shielded component that is magnetically shielded from an external magnetic field, and a housing. The housing is made from a ferritic stainless steel that has an austenitized surface layer rendered on the surface, and an internal layer portion having an internal ferrite ph

A device has a magnetically shielded component that is magnetically shielded from an external magnetic field, and a housing. The housing is made from a ferritic stainless steel that has an austenitized surface layer rendered on the surface, and an internal layer portion having an internal ferrite phase that functions as a magnetic shield for the magnetically shielded component.

대표청구항 ▼

1. A device comprising: a magnetically shielded component that is magnetically shielded from an external magnetic field; anda housing,the housing being made from a ferritic stainless steel that has an austenitized surface layer rendered on a surface, and an internal layer portion having an internal

1. A device comprising: a magnetically shielded component that is magnetically shielded from an external magnetic field; anda housing,the housing being made from a ferritic stainless steel that has an austenitized surface layer rendered on a surface, and an internal layer portion having an internal ferrite phase that functions as a magnetic shield for the magnetically shielded component,the device being a timepiece with a rotor,the magnetically shielded component being a movement inside the timepiece,the housing being a case member of the timepiece and/or a back cover disposed opposite the movement. 2. The device described in claim 1, wherein: the internal layer portion has an internal base layer of a uniform thickness not including the interfacial area between the internal layer portion and the austenitized surface layer. 3. The device described in claim 1, wherein a bottom plate located between the timepiece dial and the movement is made from a magnetic shield material. 4. The device described in claim 1, wherein: the housing is made from a Fe—Cr ferritic stainless steel base member of 17-25 wt% Cr, and nitrogen atoms are added from the surface of the base member to form an austenitized surface layer while leaving a ferrite phase internal layer portion. 5. The device described in claim 4, wherein: the Ni content of the base member is less than or equal to 0.05 wt%. 6. A method of manufacturing a housing used as an external part of a device, comprising steps of: producing a housing of the desired shape using ferritic stainless steel;converting the surface to single-phase austenite by causing nitrogen atoms to be absorbed from the surface of the housing to austenitize the entire surface and then quenching the housing; andreturning an inside portion to a ferrite phase inside layer while leaving an austenitized surface layer at the surface by heating the single-phase austenite and then cooling at a cooling rate that produces chromium nitride,the device being a timepiece with a rotor,the magnetically shielded component being a movement inside the timepiece, the housing being a case member of the timepiece and/or a back cover disposed opposite the movement.