Patent ID: 6491089
Filing Date: 2002-12-10
Classification: B22D

Abstract:
A process for manufacturing carbon steel strip having a thickness of less than or equal to 10 mm directly from liquid steel comprising the steps of:providing a liquid steel having a composition comprising, in percentages by weight based on total weight: carbon&lE;0.5%, manganese from 0.2 to 2%, silicon&lE;2%, the %Mn/%Si ratio being between 3 and 16, optionally aluminum+titanium+zirconium&lE;0. 10%, iron and usual impurities; casting said liquid steel between lateral surfaces of copper and copper alloy of two internally coated rotating horizontal rolls; said lateral surfaces of said rolls have contiguous dimples giving said surfaces a roughness Rz of between 40 and 200 &mgr;m and a roughness Ra of between 10 and 40 &mgr;m; and the atmosphere surrounding the meniscus of said liquid steel present between said rolls contains between 40 and 100% nitrogen, any balance being an inert gas insoluble in said liquid steel or of a mixture of such inert gases.