METHOD OF IRON POWDER PRODUCTION Russian patent published in 2009 - IPC B22F9/08 

FIELD: metallurgy.

SUBSTANCE: invention relates to powder metallurgy particularly dealing with production of iron powders. One provides for preparation of an iron-carbon melt containing 3.8-4.3 wt % of carbon which melt becomes atomised by compressed air to be subsequently dehydrated and dried. The resultant raw powder whose oxygen-to-carbon concentration ratio is equal to 1.8-2.2 is refined for the particle size to be below 0.250 mm and mixed with hematite powder containing at least 98% Fe₂O₃ and introduced in an amount of 4-16 wt % and graphite powder in an amount required for the mixture oxygen-to-carbon ratio to be equal to 2.2-2.4. After that the powdered mixture forming a 25-35 mm thick layer is annealed in a furnace at a temperature of 920-940°C during 1.5-2 h in an atmosphere of a gas containing at least 70 vol. % of hydrogen, no more than 28 vol. % of nitrogen and impurities (balance) including no more than 1.1 vol. % of methane and no more than 4 mg/nm³ of ammonia, the gas dewdrop temperature being equal to -25°C. The gas is delivered into the furnace in a counterflow in an amount of 120-180 nm³ per 1 ton of the powered mixture. The sinter resulting from the annealing becomes subject to fragmentation followed by extraction of the iron powder useful fraction with a grain size less than 0.2 mm.

EFFECT: provision for improved quality of the powder and sintered products produced based thereupon, extension of the products scope of application in the capacity of structural, tribotechnical and electrotechnical materials, improvement of the process technical and economic performance.

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