Properties investigation of CaO–Al2O3–SiO2–Li2O–B2O3–Ce2O3 mould flux with different w(CaO)/w(Al2O3) for heat-resistant steel continuous casting

ABSTRACTThe new CaO–Al2O3–SiO2–Li2O–B2O3–Ce2O3 mould flux was devised to realise smooth continuous casting of Ce-bearing heat-resistant steel. The new devised mould flux was based on calcium-aluminate system, so the w(CaO)/w(Al2O3) has great influence on the properties of the slag, which is similar to the basicity in the silicate system. The melting temperature, viscous properties, slag structure and crystalline phases with different w(CaO)/w(Al2O3) were investigated. The melting temperature of the mould flux could remain relatively steady with w(CaO)/w(Al2O3) in the range of 1.0–1.82. The main network former in the new slag was [AlO4]-tetrahedron. The network formed by [AlO4]-tetrahedron was destroyed by increasing w(CaO)/w(Al2O3), the viscosity decreased consequently. The mould flux show weaker crystallisation tendency with increasing w(CaO)/w(Al2O3). When the temperature decreased to 1100°C, the change of the fully crystallised phases with increasing w(CaO)/w(Al2O3) was as follows: Li2O·Al2O3 + 2CaO·Al...