METHOD FOR MANUFACTURING FERRITIC STAINLESS STEEL SLABS WITH EQUIAXED GRAIN STRUCTURES

摘要

A method for manufacturing ferritic stainless steel slabs having high equiaxed crystal ratio and manufacturing ferritic stainless steels having solidification microstructures with less ridging defects accordingly by controlling concentrations of Ti and Al in molten steel through Si/Mn/Al/Ti composite deoxidation in a vacuum decarburizing and refining process is provided. A method for manufacturing ferritic stainless steels having solidification microstructures comprises: a step of blowing oxygen into molten steel contained in a vacuum decarburizing ladle from an upper part of the ladle to conduct a decarburizing reaction; an alloying step of deoxidizing the molten steel, and injecting 0.2 to 0.4 mass% of Ti into the deoxidized molten steel; a first determining step of analyzing concentration of Al contained in the molten steel to determine whether the Al concentration is within a set value range from 0.005 to 0.12 mass% or not; a second determining step of determining whether the Al concentration of a final molten steel is within a target value range from 0.02 to 0.04 mass% or not after stirring the molten steel using an inert gas if the Al concentration satisfies the set value range; a step of continuously casting the molten steel if the Al concentration satisfies the target value range.