ROLL CASTING STEEL STRIP: COMPOSITION TO FORM LIQUID DE-OXIDATION FILM LESS THAN 5 MICRONS THICK ON ROLL SURFACE AT STEEL LIQUIDUS TEMPERATURE

摘要

Method of casting steel strip in which molten steel solidifies as a shell on a chilled casting surface (100). The casting surface (100) has a texture (101) formed by a regular pattern of surface projections (103) and depressions (102) and the steel chemistry is selected to generate in the casting pool deoxidation products which form on the casting surface (100) a layer of less than 5 microns thickness a major proportion of which is liquid during cooling of the steel to below its liquidus temperature in the formation of said solidified shell. The substantially liquid layer suppresses the formation of surface defects in the solidifying metal surface due to early deposition of solid oxides on the casting surface.