Multistep Cross Rolling of UNS S32101 Steel: Microstructure, Texture, and Magnetic Properties

Abstract

In the present study, effect of multistep cross rolling (MSCR) on microstructure, texture, and magnetic properties has been investigated for UNS S32101 steel. UNS S32101 steel consisting of almost equal proportion of ferrite and austenite was 80% cold cross rolled in multiple steps. The microstructures were characterized using optical microscopy (OM), scanning electron microscopy (SEM), and electron backscattered diffraction (EBSD), while crystallographic texture was determined by x-ray diffraction (XRD). Microstructure showed decrease in band thickness and spacing for both austenite and ferrite with increased cold-rolling reduction. Lenticular bulges were the main feature of microstructure after 80% cold rolling, indicating the presence of strain-induced martensite (SIM). Hysteresis loops were also measured in order to characterize other parameters associated with deformation and SIM. The magnetic anisotropy decreased, while coercivity (Hc), area under the B-H loop and magnetic losses increased with an increase in cold-rolling reduction. Hc was found to be directly proportional to the amount of reduction during cold rolling and inversely proportional to equivalent circle grain size. As-received sample showed strong cube ({100} ) with strong Brass ({110} ) in austenite and strong α (rolling direction, RD// ) and γ (normal direction, ND// ) fibers in ferrite. For 80% rolling, strong Brass and Goss ({110} ) were developed in austenite, while strong rotated cube ({100) ) and γ-fiber were obtained in ferrite.