Metal powder for powder metallurgy, compound, granulated powder, and sintered body

Abstract

A metal powder for powder metallurgy contains Fe as a principal component, Cr in a proportion of 10% by mass or more and 30% by mass or less, C in a proportion of 0.15% by mass or more and 1.5% by mass or less, Si in a proportion of 0.3% by mass or more and 1% by mass or less, Zr in a proportion of 0.01% by mass or more and 0.5% by mass or less, Nb in a proportion of 0.01% by mass or more and 0.5% by mass or less, and Mn and Ni in a total proportion of 0.05% by mass or more and 1.6% by mass or less. Further, the metal powder for powder metallurgy preferably has a crystal structure of martensite-based stainless steel.

What is claimed is: 
     
         1 . A metal powder for powder metallurgy, comprising:
 Fe as a principal component;   Cr in a proportion of 10% by mass or more and 30% by mass or less;   C in a proportion of 0.15% by mass or more and 1.5% by mass or less;   Si in a proportion of 0.3% by mass or more and 1% by mass or less;   Zr in a proportion of 0.01% by mass or more and 0.5% by mass or less;   Nb in a proportion of 0.01% by mass or more and 0.5% by mass or less; and   Mn and Ni in a total proportion of 0.05% by mass or more and 1.6% by mass or less.   
     
     
         2 . The metal powder for powder metallurgy according to  claim 1 , wherein the metal powder has a crystal structure of martensite-based stainless steel. 
     
     
         3 . The metal powder for powder metallurgy according to  claim 1 , wherein a content ratio of the Zr to the Nb (Zr/Nb) is 0.3 or more and 3 or less. 
     
     
         4 . The metal powder for powder metallurgy according to  claim 1 , wherein a content sum of the Zr and Nb is 0.05% by mass or more and 0.6% by mass or less. 
     
     
         5 . The metal powder for powder metallurgy according to  claim 1 , wherein when a content sum of the Zr and the Nb is represented by (Zr+Nb), a ratio of (Zr+Nb) to the Si, (Zr+Nb)/Si, is 0.1 or more and 0.7 or less. 
     
     
         6 . The metal powder for powder metallurgy according to  claim 1 , wherein the Mn is contained therein in a proportion of 0.01% by mass or more and 1.25% by mass or less. 
     
     
         7 . The metal powder for powder metallurgy according to  claim 1 , wherein the Ni is contained therein in a proportion of 0.05% by mass or more and 0.6% by mass or less. 
     
     
         8 . The metal powder for powder metallurgy according to  claim 1 , wherein the metal powder has an average particle diameter of 0.5 μm or more and 30 μm or less. 
     
     
         9 . A compound, comprising:
 a metal powder for powder metallurgy including:
 Fe as a principal component; 
 Cr in a proportion of 10% by mass or more and 30% by mass or less; 
 C in a proportion of 0.15% by mass or more and 1.5% by mass or less; 
 Si in a proportion of 0.3% by mass or more and 1% by mass or less; 
 Zr in a proportion of 0.01% by mass or more and 0.5% by mass or less; 
 Nb in a proportion of 0.01% by mass or more and 0.5% by mass or less; and 
 Mn and Ni in a total proportion of 0.05% by mass or more and 1.6% by mass or less; and 
   a binder which binds particles of the metal powder for powder metallurgy to one another.   
     
     
         10 . The compound according to  claim 9 , wherein the metal powder has a crystal structure of martensite-based stainless steel. 
     
     
         11 . The compound according to  claim 9 , wherein a content ratio of the Zr to the Nb (Zr/Nb) is 0.3 or more and 3 or less. 
     
     
         12 . The compound according to  claim 9 , wherein a content sum of the Zr and Nb is 0.05% by mass or more and 0.6% by mass or less. 
     
     
         13 . The compound according to  claim 9 , wherein when a content sum of the Zr and the Nb is represented by (Zr+Nb), a ratio of (Zr+Nb) to the Si, (Zr+Nb)/Si, is 0.1 or more and 0.7 or less. 
     
     
         14 . A granulated powder, wherein the granulated powder is obtained by granulating the metal powder for powder metallurgy according to  claim 1 . 
     
     
         15 . A granulated powder, wherein the granulated powder is obtained by granulating the metal powder for powder metallurgy according to  claim 2 . 
     
     
         16 . A granulated powder, wherein the granulated powder is obtained by granulating the metal powder for powder metallurgy according to  claim 3 . 
     
     
         17 . A granulated powder, wherein the granulated powder is obtained by granulating the metal powder for powder metallurgy according to  claim 4 . 
     
     
         18 . A granulated powder, wherein the granulated powder is obtained by granulating the metal powder for powder metallurgy according to  claim 5 . 
     
     
         19 . A sintered body produced by sintering a metal powder for powder metallurgy containing:
 Fe as a principal component;   Cr in a proportion of 10% by mass or more and 30% by mass or less;   C in a proportion of 0.15% by mass or more and 1.5% by mass or less;   Si in a proportion of 0.3% by mass or more and 1% by mass or less;   Zr in a proportion of 0.01% by mass or more and 0.5% by mass or less;   Nb in a proportion of 0.01% by mass or more and 0.5% by mass or less; and   Mn and Ni in a total proportion of 0.05% by mass or more and 1.6% by mass or less.   
     
     
         20 . The sintered body according to  claim 19 , wherein the sintered body has a relative density of 97% or more and a surface Vickers hardness of 570 or more.