Casi /Cafe Wire

Calcium treatment of Aluminum-killed clean steel

In case of Al-killed grades, the steel bath contains high melting point Al2O3 (Alumina) inclusions which can lead to  nozzle clogging at the continuous caster,  poor transverse mechanical properties after rolling, bad resistance to HIC and bad machinability.

The addition of Ca during ladle refining transform Al2O3 into (CaO)x(Al2O3)y which has low melting point and also remains globular during rolling, thus eliminateing the above problems.

                                     12 (Ca)+ 11 (Al2O3) ♦ 12 CaO.7Al2O3+8 (Al)