| 摘要 |
PURPOSE:To suppress the dimensional change of the inside circumferential surface of cylindrical structural parts uniform and small by subjecting said parts to an ionic nitriding treatment while a jig for preventing nitriding is held in tight contact with the end face of said parts. CONSTITUTION:A jig 2 for preventing nitriding is held in tight contact with the end face (b) part of a cylindrical structural part 1 having an inside circumferential surface, that is, a cylinder part (a), and the cylinder part (a) is subjected to an ionic nitriding treatment by generating glow discharge in a nitriding gaseous atmosphere. This jig 2 is opened with a through-hole (c) of approximately the same bore as that of the cylinder part (a) of the part 1 to facilitate the ionic nitriding of the part (a). The part (d) of the jig 2 is made approximately the same size as that of the outside circumference of the part 1 to facilitate positioning of the part 1 and to prevent the generation of glow discharge in the outside circumferential clearance between the end face (b) part of the part 1 and the jig 2. According to this method, it is possible to suppress the dimensional change of the cylinder bore to be caused by the ionic nitriding extremely small and uniform. |
