Influence of the Cold Rolling Conditions and the Initial Micro Structures on the Ridging Behavior in Ti-stabilized 18 Cr Ferritic Stainless Steel

摘要

The influence of the cold rolling conditions on the ridging resistance and the crystallographic texture distribution of Ti-stabilized 18% Cr ferritic stainless steel was studied in order to improve surface quality. In the present study, the effect of two sequences of cold rolling and annealing with the hot strips and the annealed hot strips as the starting materials was analyzed: a single cold rolling and annealing, and an interrupted cold rolling with an intermediate and a final anneal. In the conventional single step cold rolling, the ridging resistance was found to deteriorate with increasing cold reduction ratio. For a fixed total cold reduction ratio in the two stage cold rolling, ridging was less pronounced when a higher reduction was applied in the second step. Band-like clusters of grains with similar crystallographic orientations were observed in the mid-thickness of sheets with severe ridging. The results show that severe ridging is related to the presence of band-like clusters of non-g fiber components in a g-fiber matrix. The two stage cold rolling was found to result in less band-like clusters and an improved surface quality. Annealing of the hot strips prior the cold rolling operations was associated with an enhanced ridging resistance of the final sheets.