Continuous casting of stainless austenitic steel strips between rolls involves using rolls having surface comprising contacting circular or elliptical pits and inert gas soluble in steel around meniscus of molten metal

摘要

Stainless austenitic steel strips of thickness not greater than 10 mm are produced by continuous casting of molten metal between two cooled, rotating rolls having surface comprising contacting circular or elliptical pits of diameter 100-1500 microns and depth 20-150 microns . Inert gas soluble in the steel surrounds the meniscus of the molten metal. The molten metal comprises (in weight %) C% = 0.08, Si% = 1, P% = 0.04, Mn% = 2, Cr 17-20%, Ni% 8-10.5, S% 0.007-0.040, and Fe and production impurities the remainder. The ratio Creq/Nieq = 1.55-1.9, preferably 1.70-1.90, where Creq(%) = Cr% + 1.37 Mo% + 1.5 Si% + 2 Nb% + 3 Ti% Nieq(%) = Ni% + 0.31 Mn% + 22 C% + 14.2 N% + Cu%. The inert gas surrounding the meniscus of the molten metal is a gas that is soluble in the steel or a mixture of gases, or contains at least 50 volume % of such a gas or such a mixture of gases. The inert gas is preferably comprises a mixture of nitrogen (50-100 volume %) and argon (50-0 volume %). An Independent claim is given for a stainless austenitic steel strip of thickness 10 mm or less that can be obtained by the above process.