CORE ROD OF METALLIC MOLD FOR POWDER METALLURGY

摘要

PURPOSE: To prolong the service life of a core rod by constituting the core rod of a metallic mold for powder metallurgy to form a sintered parts having a hole of a bar-like base end part and a cylindrical tip part to increase the connecting strength of both parts. ;CONSTITUTION: This core rod 10 for metallic mold to form the steel parts 13 of a nut, etc., by the powder metallurgy method is constituted of the bar-like steel-made base end part 11 and connected quality cylindrical steel-made tip side part 12. A projecting part 11b formed with a male screw 11c is provided at the tip part of the base end part 11 and the tip side part 12 is fitted to the outer periphery of the projecting part and both parts are mutually brazed in wide contact area and tightly fixed. Further, a recessed part 12b, where at least a part of a nut member 13 screwed with the male screw 11c is invaded in the tip side part 12 is formed, and the tip side part 12 is fitted to the projecting part 11b, then the nut member 13 is screwed to the male screw part 11c to integrally connect the tip side part 12 and the base end part 11. Since the joined strength between the base end side part 11 and the tip side part 12 is high, the core rod can be used for a long time without collapse of the parts at the time of forming the nut.;COPYRIGHT: (C)1995,JPO