Grain refinement of non-magnetic austenitic steels during asymmetrical hot rolling process

Asymmetrical hot rolling (ASHR) was proposed to acquire productive grain refinement for Fe-20Mn-4Al-0.3C and Fe-18Cr-18Mn-0.5N non-magnetic austenitic steels. The intensive additional shear deformation caused by ASHR promotes the nucleation of recrystallization and grain refining of steel plates. With the speed ratio of 1.2, the austenitic grains were refined to ∼5 μm on the surface, the recrystallization fraction was enhanced to ∼34.7%, and the thickness of fine-grained surface layer increases to ∼450 μm for Fe-20Mn-4Al-0.3C steel. The Fe-18Cr-18Mn-0.5N steel also exhibited an effective surface grain refinement with an average size of ∼3 μm, and the recrystallization fraction reached ∼76.9% at the speed ratio of 1.15.