Continuous casting of steel without carbon segregation - with casting parameters adjusted to produce specific ratio of surface and core cooling rates

摘要

Steel is continuously cast with a solidus-liquidus interval greater than 55 deg.C and casting cross section smaller than 300 mm x 300 mm. The casting after exit from the mould is cooled in a secondary cooling zone. Casting parameters such as the overheating temp., casting velocity, and the length and intensity of the secondary cooling are jointly adjusted so that along a cooling section (14) bounded by the liquidus point (13) and the solidus point (15) for the centre of the continuous casting, the ratio of the cooling rate of the casting surface to the cooling rate of the central casting core is at least 0.4 (0.45-0.1). Pref. the casting parameters are adjusted so that, at the end of spray cooling, the liquidus point (13) for the centre of the casting is located within a diagram region where the casting surface is reheated during air cooling. Alternatively, these parameters are adjusted so that the liquidus point (13) is located in a region where the casting surface has reached the max. reheating temp. (7') or begins to fall again. USE/ADVANTAGE - Used in the metallurgical industry. It prevents C segregation and occurrence of cavities and/or internal cracks in the centre region of continuous castings with a small cross section.