METHOD OF STEEL OUT-FURNACE TREATMENT Russian patent published in 2009 - IPC C21C7/00 

FIELD: metallurgy.

SUBSTANCE: invention relates to ferrous metallurgy, particularly to method of out-furnace carbon steel. Method includes steel deoxidation in ladle by aluminium, metal evacuation before its blowing by argon and introduction of calcium, measurement of oxygen activity in metal before calcium introduction and finishing up to specified level of oxygen activity in melt. Amount of calcium, introduced into metal in terms of assimilated, is specified subject to required content of CaO in nonmetallic inclusion, sulphur content before treatment by calcium, oxygen activity in metal. Oxygen activity in metal is finished up to specified level by means of introduction of deoxidising agent, for instance, aluminium, one or more times. Amount of calcium, introduced into metal must fulfil condition: 0.5…2.0·α_o≤[Ca]≤2.5·[S] at oxygen activity 0.0005…0.002% and 2.0…10.0·α_o≤[Ca]≤2.5·[S] at oxygen activity 0.0001…0.0005%. Calcium is introduced into metal in the form of flux cored electrode, into composition of which it is entered calcium-bearing alloying component.

EFFECT: usage of invention provides receiving in ready metal of minimal amount of nonmetallic inclusions.

5 cl, 1 ex, 3 tbl