EFFECT OF ROUGH ROLLING CONDITION ON THE FORMABILITY AND RIDGING OF 17-PERCENT-CR STAINLESS-STEEL SHEET

The ridging quality of the 17% Cr stainless steel sheet was found to be closely associated with the rough rolling schedule in the hot rolling process. When the rough rolling is carried out in the temperature region where no substantial alpha --> gamma transformation occurs immediately after the final rough rolling pass, namely final rough rolling is carried out in alpha-single phase or in gamma + alpha dual phases before and after final pass in the rough rolling with the inter-pass time of about 30 s, the static recrystallization in the rough rolling process is promoted and the ridging of the final annealed sheet is remarkably improved even processed without hot band annealing. The riding quality is not improve when alpha --> gamma transformation occurs immediately after the rough rolling as the static recrystallization after rough rolling is suppressed by the transformation even with inter-pass time longer than 30 s. Base on this finding, the new hot rolling method referred as "IRP" (Inter-pass Recrystallization Process) has been developed.