PROCEDURE FOR FABRICATION OF FORGED PIECES OF LOW CARBON FERRITE-PEARLITE STEELS

摘要

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.;1 ex, 2 tbl