Process of making parts by powder metallurgy and preparing a powder for use therein

Claim 1

THE PROCESS OF PREPARING A POWEDERED METAL PRODUCT FOR USE IN POWDER METALLURGY FROM A SOLID STARTING MATERIAL WHICH CONSISTS PREDOMINANTLY OF IRON IN THE FORM OF AT LEAST ONE OF THE OXIDES OF IRON, SAID STARTING MATERIAL ALSO CONTAINING (A) NICKEL, FROM ABOUT 1/2% TO ABOUT 3% (CALCULATED AS METAL BASED ON THE TOTAL METAL PRESENT), SAID NICKEL BEING PRESENT IN SAID STARTING MATERIAL IN A FORM WHICH IS SELECTED FROM THE OXIDES AND THE CHLORIDES OF NICKEL, AND (B) A MATERIAL TO ASSIST THE ASSIMILATION OF CARBON WHICH IS SELECTED FROM THE GROUP CINSISTING OF MOLYBDENUM AND MANGANESE, AND WHICH IS PRESENT IN A CONCENTRATION FROM ABOUT 0.1% TO ABOUT 2% (CALCULATED AS METAL BASED ON THE TOTAL METAL PRESENT), THE MANGANESE (WHEN PRESENT) BEING IN A FORM WHICH IS SELECTED FORM FERRO-MANGANESE AND MANGANESE OXIDE AND CHLORIDE, AND THE MOLYBDENUM (WHEN PRESENT) BEING IN A FORM SELECTED FROM METALLIC MOLYBDENUM AND MOLYBDENUM OXIDE AND CHLORIDE; SAID PROCESS COMPRISING THE STEPS OF CO-REDUCING SAID STARTING MATERIAL BY CONTACTING IT IN A REDUCING ZONE WITH A GASEOUSD REDUCING ATMOSPHERE CONTAINING HYDROGEN AS AN ESSENTIAL REDUCING AGENT AND CONTAINING HYDROGEN CHLORIDE WHICH IS PRESENT IN A VOLUME CONCENTRATION FROM ABOUT 1 TO 8% BASED UPON THE TOTAL OF HYDROGEN PLUS HYDROGEN CHLORIDE PRESENT; MAINTAINING THE SOLID MATERIALS IN SAID REDUCING ZONE IN THE TEMPERATURE RANGE OF ABOUT 1000* F.TO ABOUT 1800* F., AND SUPPLYING AT LEAST A PART OF THE HYDROGEN CHLORIDE, WHICH IS NECESSARY TO MAINTAIN THE CONCENTRATION THEREOF AS AFORESAID, FROM A SOURCE SEPARATE AND DISTINCT FROM SAID STARTING MATERIAL, THE HYDROGEN CHLORIDE CONCENTRATION BEING MAINTAINED AS AFORESAID THROUGHOUT THE CO-REDUCTION OF SAID STARTING MATERIAL; AND FOLLOWING THE CO-REDCTION STEP AFORESAID, COOL-OLDING THE REDUCED MATERIAL PRODUCED AS AFORESAID UNDER NONOXIDIZING CONDITONS TO A TEMPERATURE SUCH THAT IT MAY BE EXPOSED TO THE ATMOSPHERE WITHOUT SUBSTANTIAL SPONSTANEOUS OXIDATION.