| abstract |
The invention belongs to the field of auxiliary materials for smelting steel, in particular to a covering slag for a pre-melting continuous casting crystallizer. The weight percentage components of the covering slag are as follows: 31 to 36 percent of SiO2, 30 to 35 percent of CaO, 2 to 5 percent of MgO, not more than 1.5 percent of Fe2O3, 2 to 5 percent of Al2O3, 8 to 11 percent of Na2O, 5 to 8 percent of F, 0.8 to 1.5 percent of Li2O, 3 to 6 percent of C and the rest are unavoidable impurities. The covering slag has a good liquidity and spreadability, can uniformly cover the surface of molten steel, has no piling phenomenon, and has the advantages of active slag surface, uniform melting and no caking phenomenon. The invention has a better insulating performance and has no cold steel agglomerated on the liquid surface; can ensure a casting blank to be fully lubricated so as to realize a high pulling rate; has a stable performance after absorbing the impurities and can realize stable and smooth continuous manufacture; avoids the steel leakage phenomenon, improves the casting blank quality and can lead the longitudinal crack of a plate blank and the angle part cross crack to be reduced by more than two third averagely; the invention has a low cost and is convenient for popularizing. |