Speaker
Description
FeMnAlC lightweight steel exhibits a narrow hot-working window. In industrial rolling, shear stress and dynamic parameter variations are unavoidable and may induce defects. This study compares the hot deformation behavior of Fe-25Mn-5Al-0.7C steel under uniaxial compression versus shear compression using Gleeble 3800 tests at 950–1100 °C and 0.01–10 s⁻¹, including sudden temperature/strain rate changes. Microstructure was characterized by OM, SEM and XRD, and a DRX kinetic model was implemented into Deform 3D. The results show that shear stress significantly enlarges the instability region on processing maps and narrows the safe window to T > 1075 °C and ε ̇< 0.015 s⁻¹. Direct comparison between uniaxial and shear compression tests confirms that the presence of shear stress is largely responsible for defect formation (e.g., banded structures, flow localization) during rolling. Increasing temperature or strain rate eliminates such defects, while a sudden strain rate rise promotes DRX nucleation and improves uniformity. A temperature modified DRX model well predicts the microstructural evolution. These findings provide a theoretical basis for minimizing shear induced defects in industrial hot rolling of FeMnAlC lightweight steel.
| Speaker Company/University | Politecnico di Milano |
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