Patent ID: 6355087
Filing Date: 2002-03-12
Classification: B22F,C21D,C22C

Abstract:
A process of preparing an iron-based powder having less than 0.25% by weight of oxygen and less than 0.01% by weight of carbon comprising the steps ofa) water-atomising a raw powder consisting essentially of iron and optionally at least one alloying element selected from the group consisting of chromium, managanese, copper, nickel, vanadium, niobium, boron, silicon, molybdenum and tungsten and having a carbon content between 0.1 and 0.9% by weight and an oxygen/carbon weight ratio of about 1 to 4 and at most 0.5% of impurities; b) charging a gas tight furnace with the powder in essentially inert gas atmosphere and closing the furnace; c) increasing the furnace temperature to a temperature between 800 and 1350Â° C. d) monitoring the increase of the formation of CO gas in the furnace and evacuating gas from the furnace when a significant increase of the CO formation is observed; and e) cooling the powder when the increase of the formation of CO gas diminishes.