Impact of fast heating and cooling on the mechanical behaviour of alumina-magnesia refractory castables

• Published in: Ceramics international Vol. 49; no. 22; pp. 36507 - 36515
• Main Authors: Dai, Yajie, Zhu, Haixia, Zhu, Qingyou, Wang, Fei, Liao, Ning, Li, Yawei, Konietzky, Heinz, Aneziris, Christos G.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.11.2023
• Subjects: Alumina-magnesia castables; Calcium hexaluminate; Damage process; Heat treatment; Induction heating; Heat treatment; Alumina-magnesia castables; Calcium hexaluminate; Damage process; Induction heating
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2023.08.334

The alumina-magnesia castables is one kind of monolithic refractories for steel ladle, whose thermo-mechanical properties vary with temperature during the lining pre-heating process and metallurgical service. The understanding of their variation tendency and sensibility to temperature fluctuation is important for the improvement of high-efficiency pre-heating strategy and real-time service performance. In this study, the influence of heat treatment temperature and heating/cooling rate on the thermo-mechanical properties and fracture behaviour of alumina-magnesia castables is investigated using uniaxial compressive tests equipped with an induction heating system and Brazilian test combined with digital image correlation and acoustic emission. The brittleness and mechanical strength of alumina-magnesia castables increase with heat treatment temperature due to the better sintering and formation of calcium hexaluminate and spinel phases. Without full relaxation of residual stresses, the stiffness increases while the strength decreases after fast heating of 200 °C/min. Meanwhile. the same castables after different thermal treatments show disparate mechanical responses to cooling rates.