Effect of Martensite on Deformation Structure and Recrystallization Behavior in Ferritic Stainless Steel

To improve the surface quality of 16mass%Cr ferritic stainless steel sheet processed by cold-rolling and annealing, the role of the hard martensite phase, in particular, the hardness ratio k between martensite and ferrite prior to cold-rolling on microstructure evolution was investigated by varying the k value through changing tempering temperatures after intercritical annealing. The specimen with k>2.0 exhibits the extremely heterogeneous deformation. In particular, ferrite around martensite becomes prominently strained. The specimen with k 2.0 provides the nucleation site of recrystallization leading to fragmenting the elongated {100} colony, and the orientation is randomized. Consequently, the presence of martensite prior to cold-rolling is effective to prevent the ridging of ferritic stainless steel sheets.