Hot Deformation Behavior of an API X70 Steel: A Processing Map Approach
نویسندگان
1 Department of Materials Science and Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran
2 Department of Materials Science and Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran
3 Department of Materials Science and Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran
4 Department of Materials Science and Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran
doi
10.22099/ijmf.2025.53864.1341چکیده
This study investigates the hot deformation behavior of an API X70 microalloyed steel using a processing map approach. Cylindrical specimens were subjected to compression tests at temperatures ranging from 950 to 1100 °C and strain rates from 0.001 to 1 s⁻¹. Flow curves revealed typical features of work hardening, dynamic recovery, and dynamic recrystallization. Power dissipation efficiency and instability criteria were calculated using a dynamic material model to construct processing maps at various strain levels. The maps identified three optimal hot deformation regions at higher strains, with the most favorable zone (efficiency of 25–33%) located at 1075–1100 °C and 0.001–0.005 s⁻¹. Microstructural validation confirmed these safe zones, while unstable regions were characterized by crack formation and deformation bands. A constitutive analysis yielded an apparent activation energy for hot deformation of 572.5 kJ/mol. The findings provide valuable guidance for optimizing hot working conditions of API X70 steel.
