Ridging Control in Transformable Ferritic Stainless Steels

An alloy design concept leading to an improved ridging resistance in the transformable ferritic stainless steels is introduced. It is based on achieving a small γ-phase fraction at the ingot soaking temperature. The γ-phase fraction is then increased to a maximum value during the early stages of hot rolling. The nucleation of γ-phase islands in the ferritic matrix increases the fraction of transformed ferrite. The multiplicity of crystallographic orientations resulting from the α→γ and γ→α transformations leads to a pronounced weakening of the as-cast texture and an increased ridging resistance.