Stainless steel powder for high temperature applications

Abstract

A method of producing parts from powdered metal comprising the steps of providing a metallurgic powder comprising iron, 0-0.6 weight percent carbon, 0.5-5.0 weight percent silicon, 0.5-6.0 weight percent nickel, 0.5-1.5 weight percent molybdenum, 0-0.7 weight percent manganese, and 12-20 weight percent chromium, the weight percentages calculated based on the total weight of the powder. Secondly, the powders are compressed at a pressure of 35 to 65 tsi to provide a green compact. Then, the compact is heated in an atmosphere to a temperature of 2100° F. to 2400° F. for 20 to 90 minutes, such that the resulting microstructure of the compact is either single phase ferritic or dual phase ferritic and austenitic.

1 . A method of producing parts from powdered metal comprising the steps of: 
 a) providing a metallurgic powder comprising iron, 0-0.6 weight percent carbon, 0.5-5.0 weight percent silicon, 0.5-6.0 weight percent nickel, 0.5-1.5 weight percent molybdenum, 0-0.7 weight percent manganese, and 12-20 weight percent chromium, the weight percentages calculated based on the total weight of the powder;    b) compressing the metallurgic powder at a pressure of 35 to 65 tsi to provide a green compact; and    c) heating the compact in an atmosphere to a temperature of 2100° F. to 2400° F. for 20 to 90 minutes, such that microstructure of the compact has a duplex phase or a single phase, the duplex phase having both ferritic and austenitic phases and the single phase having only a ferritic phase.    
     
     
         2 . The method of  claim 1 , wherein the parts are rings used in a variable turning geometry turbocharger.  
     
     
         3 . The method of  claim 1 , wherein the step of compressing the metallurgic powder produces a compact with a density of 6.0 g/cc to 7.0 g/cc.  
     
     
         4 . The method of  claim 1 , wherein the atmosphere in which the compact is heated is selected from the group consisting of: 
 a) H 2 ;    b) N 2 /H 2 ; and    c) vacuum.