Fabrication method of alloy parts by metal injection molding and the alloy parts

Abstract

Provided is a method of manufacturing a part and the part capable of manufacturing a high value-added precision part having a low sintering temperature, a good hardness, and a good productivity at a low cost. The method includes steps of: mixing a material of from 40 to 75 wt % selected from the group consisting of Fe and a combination of Fe and Co, a material of 20 wt % or more selected from the group consisting of W, Mo, Cr, Nb, V, and Ni, a material of from 2 to 14 wt % selected from the group consisting of B, C, Cu, and Si, alloy powder having a composition including unavoidable impurities, and a binder; performing an injection molding on the mixture to form the injection moldings to have a shape of the part; removing the binder from the injection moldings; and sintering the injection moldings from which the binder is removed.

1 . A method of manufacturing an alloy part, comprising steps of:
 mixing a material of from 40 to 75 wt % selected from the group consisting of Fe and a combination of Fe and Co, a material of 20 wt % or more selected from the group consisting of W, Mo, Cr, Nb, V, and Ni, a material of from 2 to 14 wt % selected from the group consisting of B, C, Cu, and Si, alloy powder having a composition including unavoidable impurities, and a binder;   performing an injection molding on the mixture to form the injection moldings to have a shape of the part;   removing the binder from the injection moldings; and   sintering the injection moldings from which the binder is removed.   
   
   
       2 . The method of  claim 1 , wherein the alloy powder has a composition of 20 to 35 wt % Cr, 1 to 2.5 wt % Si, 0.5 wt % or less C, 0.1 to 3 wt % Cu, 2 to 5 wt % B, 0.1 to 8 wt % Mo, 14 to 22 wt % Ni, and 4 to 16 wt % Co. 
   
   
       3 . The method of  claim 1 , wherein the alloy powder has a composition of 40 to 50 wt % Cr, 1 to 2.5 wt % Si, 0.5 wt % or less C, and 5.6 to 6.2 wt % B. 
   
   
       4 . The method of  claim 1 , wherein the step of sintering is performed in a vacuum in a reducing gas or an inert gas atmosphere at a temperature of from 1100° C. to less than a melting point of the alloy. 
   
   
       5 . The method of  claim 4 , wherein the sintering temperature ranges from 1150° C. to less than the melting point of the alloy. 
   
   
       6 . The method of  claim 1 , wherein an average size of the alloy powder ranges from 0.01 to 100 μm. 
   
   
       7 . The method of  claim 1 , wherein the step of removing the binder is performed by heating the injection moldings at a temperature of from 300 to 700° C. in a reducing gas, an inert gas, or a mixture of the reducing gas and the inert gas atmosphere and maintaining the temperature for 0.5 to 5 hours. 
   
   
       8 . An alloy part manufactured by performing steps of:
 mixing a material of from 40 to 75 wt % selected from the group consisting of Fe and a combination of Fe and Co, a material of 20 wt % or more selected from the group consisting of W, Mo, Cr. Nb, V, and Ni, a material of from 2 to 14 wt % selected from the group consisting of B, C, Cu, and Si, alloy powder having a composition including unavoidable impurities, and a binder;   performing an injection molding on the mixture to form the injection moldings to have a shape of the part;   removing the binder from the injection moldings; and   sintering the injection moldings from which the binder is removed.   
   
   
       9 . The alloy part of  claim 8 , wherein the alloy powder has a composition of 20 to 35 wt % Cr, 1 to 2.5 wt % Si, 0.5 wt % or less C, 0.1 to 3 wt % Cu, 2 to 5 wt % B, 0.1 to 8 wt % Mo, 14 to 22 wt % Ni, and 4 to 15 wt % Co. 
   
   
       10 . The alloy part of  claim 8 , wherein the alloy powder has a composition of 40 to 50 wt % Cr, 1 to 2.5 wt % Si, 0.5 wt % or less C, and 5.6 to 6.2 wt % B. 
   
   
       11 . The alloy part of  claim 8 , wherein a porosity of the part is a volume fraction of 7% or less. 
   
   
       12 . The method of  claim 2 , wherein an average size of the alloy powder ranges from 0.01 to 100 μm. 
   
   
       13 . The method of  claim 3 , wherein an average size of the alloy powder ranges from 0.01 to 100 μm.