PROCEDURE FOR FABRICATION OF FORGED PIECES OF LOW CARBON FERRITE-PEARLITE STEELS Russian patent published in 2011 - IPC C21D8/00 C21D1/25 C21D1/78 

FIELD: metallurgy.

SUBSTANCE: procedure for fabrication of forged pieces out of low carbon ferrite-pearlite steels consists in melting, casting steel, forging and thermal treatment. Also, steel is cast with a lift tube under layer of slag at rate of 2-2.5 t/min. Before forging an ingot is heated in furnace at temperature 1200-1220°C and conditioned on base of calculation τ=1.1-1.3 d_avmin per mm of cross section of medium diametre of the ingot. Final thermal treatment is performed in three stages: first there are performed two quenching operations at temperature of heating T₁=Ac₃+(30-50°C) and T₂=Ac₃±20°C - cooling in water, further tempering at temperature 650-670°C with cooling in water.

EFFECT: raised cold resistance of low carbon ferrite-pearlite steels.

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