Effect of MgO on Crystallization Properties of Mold Flux for Ultra-wide Slab Peritectic Steel

Controlling the heat flux at meniscus is one of the key aspects to prevent the formation of cracks during the continuous casting of crack-sensitive steel. This study investigated the influence of MgOMgO addition on the performance of moldMold slag in the production of ultra-wide strand with a cross-section of 3000 mm × 150 mm. The main results indicated that when MgOMgO increased from 0 to 8 wt%, the crystallization of slag film gradually decreased to 0% and then gradually increased. The break temperatureBreak temperature and melting point also have the same change rule. When MgOMgO was below 6 wt%, the O2− ionized from MgOMgO destroyed the silicon-oxygen tetrahedron structure of the flux and inhibited crystallization. Conversely, magnesia alumina spinel would form in the flux. XRD results also confirmed these results. This study provided a new idea for the composition optimization of mold fluxMold flux for continuous casting of large cross-section peritectic steel.