POWDER FORGED MEMBER, POWDER MIXTURE FOR POWDER FORGING, METHOD FOR PRODUCING POWDER FORGED MEMBER, AND FRACTURE SPLIT TYPE CONNECTING ROD USING THE SAME

摘要

The present invention provides a powder forged memberin which fatigue strength is improved while securing itsmachinability without increasing its hardness, and self-consistencyafter fracture split can be secured, a methodfor producing the same, and a fracture split typeconnecting rod using the powder forged member. The powderforged member is obtained by forging a sintered preform ata high temperature, the sintered preform formed bysubjecting a powder mixture to preliminary compacting andthereafter sintering the subjected compacted preform. Thesintered preform has a ratio of free Cu of 10% or less uponthe start of the forging. The component composition of thepowder forged member after the forging is composed of, C:0.2 to 0.4% by mass, Cu: 3 to 5% by Mass, Mn: 0.5% by massor less (excluding 0), and the balance iron with inevitableimpurities, and has a ferrite ratio of 40 to 90%.