METHOD FOR PRODUCING EXTREMELY LOW CARBON STEEL SHEET AND EXTREMELY LOW CARBON CAST PIECE HAVING EXCELLENT SURFACE CHARACTERISTICS, WORKABILITY AND FORMABILITY

摘要

A method of producing an extremely low carbon steel cast slab characterized by casting molten steel obtained by reducing the carbon concentration of the molten steel to 0.005 mass% or less, then adding Cu, Nb, and B to the molten steel, furthermore, and adjusting the concentration of dissolved oxygen in the molten steel to 0.01 mass% to 0.06 mass% and extremely low carbon steel plate comprised of steel containing C: 0.005 mass% or less, acid soluble Al: 0.005 mass% or less, and further Cu, Nb, and B, characterized in that the steel has fine oxides of a diameter of 0.5 µm to 30 µm dispersed in it in an amount of 1000 particles/cm² to 1,000,000 particles/cm².