Abstract: For insuring the consumption of mold fluxes and lubricating the slab with CaO-Al2O3 mold fluxes during casting high aluminium TRIP steel，the effects of different w(CaO)/w(Al2O3) on melting and flow behaviors were studied. The results showed that the melting temperature increased and then decreased with the increase of w(CaO)/w(Al2O3), being a maximum at w(CaO)/w(Al2O3)=1.2. The trend of melting temperature change (with w(CaO)/w(Al2O3)) was contrary to the trend of liquidus temperature change of CaO-Al2O3 phase diagram. With the increase of w(CaO)/w(Al2O3), the viscosity firstly decreased and then increased. When w(CaO)/w(Al2O3)=0.5~2.3, the change of viscosity became mild, where the value of viscosity was 0.08~0.142 Pa?s. The break temperature varied with w(CaO)/w(Al2O3), being a minimum at w(CaO)/w(Al2O3)=2.0. Taking into account the melting temperature, viscosity, break temperature and crystallization behaviors of the mould fluxes, the optimum w(CaO)/w(Al2O3) was 1.5~2.0.

Key words: high aluminium TRIP steel, CaO-Al2O3 based mould fluxes, melting temperature, viscosity, break temperature