BALL SCREW SHAFT AND ITS HARDENING METHOD

摘要

PROBLEM TO BE SOLVED: To distinguish a ball screw shaft heat-treated by the in-oil induction hardening from a product which is not heat-treated yet.

SOLUTION: A colored part 3 of a blue oxide film by the bluing in an area of both ends of a screw groove 2 unnecessary for any hardened layer and capable of preventing a ball from being rolled by dropping the temperature rise by the induction hardening in oil to be in a range of 200-700°C. A ball screw shaft 1 heat-treated by the in-oil induction hardening is distinguished from a product which is not heat-treated yet by the blue color by the bluing.

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