Effect of initial solidified structure on ridging phenomenon and texture in type 430 ferritic stainless steel sheets

This study investigated the effect of the initial solidified structure on the ridging phenomenon and the texture in type 430 ferritic stainless steel sheets that have alpha+gamma two-phases at high temperature. The initial solidified structure with equiaxed or columnar grains was used and the effect of annealing of hot-rolled sheet on the texture formation during cold rolling and annealing was investigated. The effect of the initial solidified structure on the ridging phenomenon differed depending on annealing of hot-rolled sheet. With annealing of hot-rolled sheet, the columnar grain specimen exhibited severer ridging than the equiaxed grain specimen. On the other hand, without annealing of hot-rolled sheet, there was no effect of the initial solidified structure, and both specimens showed slight ridging. The columnar grain specimen with {001}<uv0> initial texture had strong {001}<110> texture after hot rolling and annealing, and the grain colonies with {001}<110> and {112}<110> orientations were identified after cold rolling and annealing. However, without annealing of hot-rolled sheet, the equiaxed and columnar grain specimens showed roughly random textures. In the case without annealing of hot-rolled sheet, the deformation zone forming around the hard alpha' phase during cold rolling was effective for no influence of the initial solidified structure and the microstructure before cold rolling.