Post-delubrication peening for forged powder metal components

Abstract

A process of forming powder metal components which minimizes decarburization and oxidation of the component prior to final forging. The process begins by molding powder metal material into a preform configuration. The preform is delubricated to extract lubricant found in the pores of the preform. Passing the preform through a shot peening operation closes a majority of the surface pores creating a densified layer within which interconnected pores are eliminated. Following post-delubrication peening (PDP), the component is sintered and then forged into its final configuration.

What is claimed is:  
     
         1 . A process for the manufacture of powder metal components comprising the steps of: 
 molding a powder metal material into a preform configuration;    delubricating said powder metal preform;    subjecting said powder metal preform to shot peening to density an outer layer of said preform;    sintering said shot peened preform; and    forging said sintered preform.    
     
     
         2 . The process as defined in  claim 1  wherein said powder metal preform is subjected to a shot speed of less than 100 meters per second.  
     
     
         3 . The process as defined in  claim 1  wherein said powder metal preform is delubricated at a temperature between 1200° F. and 1800° F. in an atmosphere which includes N 2  and H 2 .  
     
     
         4 . A process for the manufacture of powder metal components comprising the steps of: 
 molding a powder metal material into a preform configuration; subjecting said preform to a process for densifying the surface of said preform;    sintering said preform; and forging said preform.    
     
     
         5 . The process of  claim 4  wherein said surface densification process comprises shot peening.  
     
     
         6 . The process of  claim 5  wherein the shot hardness is between 47 to 51 Re.  
     
     
         7 . The process as defined in  claim 5  wherein said powder metal preform is subjected to a shot speed of less than 100 meters per second.  
     
     
         8 . The process as defined in  claim 4  wherein said sintering of said preform is preformed in a furnace less than 2,450° F.  
     
     
         9 . The process as defined in  claim 8  wherein said perform is sintered in said furnace for less than 60 minutes.