Development and Application of Basic Dam Block for Tundish

摘要

In order to develop a high performance basic dam block for the tundish vessel in steelmaking, the influences of raw materials, binders, and additives on the hydration and high temperature properties of magnesia castables were studied. Crack initiation and propagation in cement-bonded magnesia castables caused by the slaking of magnesia aggregate during drying were suppressed by replacing magnesia powder with spinel aggregate. In the case of Na_2O centre dot 2CaO centre dot P_2O_5 (NC_2P) bonded castables, the slaking of magnesia aggregate that initiates cracks could be suppressed by adding a sufficient amount of phosphate, but hot bending strength was reduced with excess amounts of phosphate. Mechanical properties of NC_2P-bonded castables at high temperatures were improved by using magnesia aggregates of low SiO_2 contents.