CONTROL OVER ULTRA-LOW TITANIUM CONTENT IN ULTRA-LOW-CARBON Al-Si KILLED STEEL Russian patent published in 2014 - IPC C21C5/54 

FIELD: metallurgy.

SUBSTANCE: invention can be used for adjustment of titanium ultra-low content in ultra-low-carbon Al-Si killed steel. Said ultra-low content in ultra-low-carbon Al-Si killed steel features the following composition, wt %: C≤0.005, Si 0.1-3.45, Mn 0.1-0.5, P≤0.2, S≤0.002, Al 0-1.2, N≤0.005, Ti≤0.0015, Fe and unavoidable impurities making the rest. Liquid steel of said composition is produced by hot pre-treatment, melting and circulation evacuation (RH) of purified melt and cast. Note here that ladle top slag is modified by feed of calcium-aluminium-based modifier in amount of 0.6-1.7 kg/t of steel for guaranteed fulfilment of control requirements. This is made in compliance with termination of RH-purified decarbonisation is terminated when total content of iron (T.Fe) in composition of top slag should make ≥5%, while content of Al₂O₃ should equal ≤23%. Note here that after RH-purified decarbonisation for killing and alloying, used are ferrosilicon, ferroaluminium and ferromanganese. Then, deep desulphurisation with its efficiency of 50-70%.

EFFECT: decreased content of titanium at low costs.

3 cl, 1 tbl, 4 dwg