| 摘要 |
1479745 Continuous casting VEREINIGTE OSTERREICHISCHE EISEN-UND STAHLWERKE-ALPINE MONTAN AG 7 Nov 1974 [8 Nov 1973] 48308/74 Heading B3F To limit corrosion by liquid slag, of the surface of a steel strand, such as a slab, being withdrawn from a cooled oscillating mould wherein the steel is covered by a layer of slag-producing powder, the surface temperature of the strand in the secondary cooling zone (lying between 800 and 1250‹ C) and the softening temperature of the powder and slag (lying between 750 and 1150‹ C.) are related so that while passing through the cooling zone, for a given strand length, the strand surface temperature should be at the most 150‹ C. above the slag softening temperature although if the maximum limit is exceeded by any part of the surface of the length it is not exceeded for more than two minutes. The softening temperature of the slag, above which liquid phases occur, is determined by taking samples from the mould. If a suitable powder has not been chosen, fluxing agents are added to correct the softening temperature. In the graph, in which the slag softening temperature is plotted as abscissa against the strand surface temperature as ordinate, the line 4 represents surface temperatures (150‹ limit) above which slag influence for more than two minutes may cause cracks. The surface temperature of the strand is measured at a number of points, e.g. pyrometrically, and the secondary cooling water regulated accordingly. Compositions of steel, powder and slag are given. |
