To provide a nitriding treatment method of a thin plate-shaped bearing member, by which the occurrence rate of defective thin plate-shaped bearing members with stains can be efficiently reduced.
The nitriding treatment method comprises sequentially subjecting a plurality of the thin plate-shaped bearing members, which are held by a jig, to a degreasing step, a deburring step, a cleaning step, a nitriding step, a cooling step, a cleaning step and a drying step, while the jig supports the thin plate-shaped bearing members in a state that their plate faces become parallel to a plane other than a horizontal plane without contacting each other. The final treatment in the cleaning step is carried out by a method chosen from: a method of soaking the thin plate-shaped bearing members in a water displacement agent; a method of soaking the same in a water displacement agent and subsequently drying the same; a method of soaking the same in pure water; a method of soaking the same in pure water and subsequently drying the same; a method of soaking the same in an aqueous solution of a cyanide compound; and a method of soaking the same in an aqueous solution of a cyanide compound and subsequently drying the same.
Megumi Konishi
Hide Tanaka Tetsu
Ichi Hirose
Toru Miyasaka