| 摘要 |
PROBLEM TO BE SOLVED: To provide a feed screw of structure having non-magnetic action higher than that of non-magnetic stainless steel, harmless to a human body and cheap like non-magnetic stainless steel. SOLUTION: This feed screw is provided with a screw shaft 1 and a nut 2 relatively slidably screwed onto the screw shaft 1 and at least with one of the screw shaft and the nut formed of a Mn-Ni-Cu-based alloy. Like non- magnetic stainless steel, the Mn-Ni-Cu-based alloy does not contain components toxic to a human body, and can be much more cheaply manufactured compared to ceramics. Further, the relative magnetic permeability of the alloy is closer to 1 compared to that of non-magnetic stainless steel.
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