This study investigated the hot deformation behavior and dynamic recrystallization (DRX) characteristics of a coarse-grained Fe-24Mn steel slab using plane strain compression (PSC) tests. Tests were conducted at 900-1,000 °C and strain rates of 0.5-10 s-1. Constitutive equations based on the Zener-Hollomon parameter accurately predicted flow stress ( ). A processing map based on the Dynamic Materials Model (DMM) predicted flow instability at high strain rates (10 s-1) due to a negative strain rate sensitivity exponent. However, electron backscatter diffraction (EBSD) analysis revealed that these regions actually exhibited a fully recrystallized microstructure with low Kernel Average Misorientation (KAM) values, contradicting the DMM prediction. This discrepancy is attributed to adiabatic heating during high-speed deformation, which induces thermal softening and provides the driving force for DRX. Consequently, the region with negative power dissipation efficiency at high strain rates should be reinterpreted not as a failure zone, but as a window for efficient microstructural refinement. The study identifies 950 °C and 10 s-1 as the optimal processing conditions for grain refinement of the as-cast slab.

Abstract
1. 서 론
2. 실험 방법
3. 결과 및 고찰
    3.1. 유동 곡선
    3.2. 구성 방정식
    3.3. 공정 지도
    3.4. 미세 조직 진화
    3.5. 공정 지도와 미세조직 간의 상관관계
4. 결 론
Acknowledgement
References
<저자소개>

• 이창우((재)포항소재산업진흥원 강관기술센터) | Changwoo Lee (Steel Pipe Technology Center, Pohang Institute of Materials Industry Advancement, Pohang 37923, Republic of Korea) Corresponding author
• 이재준((재)포항소재산업진흥원 강관기술센터) | Jae Jun Lee (Steel Pipe Technology Center, Pohang Institute of Materials Industry Advancement, Pohang 37923, Republic of Korea)
• 김병구(한국생산기술연구원 에너지소재부품연구그룹) | Byoungkoo Kim (Advanced Energy Materials and Components R&D Group, Korea Institute of Industrial Technology, Busan 46938, Republic of Korea)