Method for manufacturing sintered body and sintered body

Abstract

A sintered body manufacturing method includes: a preparation step of preparing a raw material powder containing an iron-based metal powder; a molding step of subjecting the raw material powder to uniaxial pressing using a die to produce a green compact having an overall average relative density of 93% or more; a machining step of machining the green compact to produce a machined compact; and a sintering step of sintering the machined compact to obtain a sintered body.

1 . A method for manufacturing a sintered body, the method comprising:
 a preparation step of preparing a raw material powder containing an iron-based metal powder;   a molding step of subjecting the raw material powder to uniaxial pressing using a die to produce a green compact having an overall average relative density of 93% or more;   a machining step of machining the green compact to produce a machined compact; and   a sintering step of sintering the machined compact to obtain a sintered body.   
     
     
         2 . The method for manufacturing a sintered body according to  claim 1 , wherein, in the machining step, the green compact is machined into a helical gear shape. 
     
     
         3 . The method for manufacturing a sintered body according to  claim 1 , wherein the uniaxial pressing is performed at a pressure of 600 MPa or higher. 
     
     
         4 . The method for manufacturing a sintered body according to  claim 1 , wherein the machining step is performed using a cutting method. 
     
     
         5 . The method for manufacturing a sintered body according to  claim 1 , wherein the machining step is performed while compressive stress is applied to the green compact in such a direction that tensile stress acting on the green compact from a working tool is counteracted. 
     
     
         6 . A sintered body composed of an iron-based material comprising:
 an average relative density of the whole sintered body being 93% or more.   
     
     
         7 . The sintered body according to  claim 6 , wherein the sintered body is a helical gear. 
     
     
         8 . The sintered body according to  claim 7 , wherein the helical gear has teeth inclined 30° or more with respect to an axial line of the helical gear.