Ali, M., Seppälä, O., Fabritius, T., & Kömi, J. (2022). Microstructure evolution and static recrystallization kinetics in hot-deformed austenite of coarse-grained Mo-free and Mo containing low-carbon CrNiMnB ultrahigh-strength steels. Materials Today Communications, 33, 104676. https://doi.org/10.1016/j.mtcomm.2022.104676
Microstructure evolution and static recrystallization kinetics in hot-deformed austenite of coarse-grained Mo-free and Mo containing low-carbon CrNiMnB ultrahigh-strength steels
|Author:||Ali, Mohammed1,2; Seppälä, Oskari1; Fabritius, Timo3;|
1Materials and Mechanical Engineering, Centre for Advanced Steel Research, University of Oulu, P.O. Box 4200, FI-90014 Oulu, Finland
2Steel Technology Department, Central Metallurgical Research and Development Institute, Helwan 11421, Egypt
3Process Metallurgy Research Unit, Centre for Advanced Steel Research, University of Oulu, P.O. Box 4300, FI-90014 Oulu, Finland
|Online Access:||PDF Full Text (PDF, 14.3 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe2022102062628
|Publish Date:|| 2022-10-20
The static recrystallization characteristics and microstructure evolution in hot-deformed austenite were evaluated for a newly developed low-carbon CrNiMnB ultrahigh-strength steel with and without molybdenum addition. The time for 50% static recrystallization (t50%) over a wide range of strains and hot-deformation temperatures were obtained using the stress-relaxation technique on Gleeble thermomechanical simulator. Moreover, effect of deformation parameters on the size distribution and average size of prior austenite grains are investigated. A novel semi-automatic stress relaxation test reading tool with a graphical user interface was created and used successfully for the current study. The obtained results of strain‘s power and the apparent activation energy are within the range stated in literature for C-Mn and microalloyed steels. Addition of molybdenum increase the power of strain and the apparent activation energy from − 1.9 to − 2.6 and 206 to 212 kJ/mol, respectively. The retardation effect of molybdenum addition was shown by a new regression equation devised for calculating t50%. The developed equations show a good agreement with the experimental data and can be used in the designing of roughing during thermomechanical processing. The deformation parameters i.e., temperature, strain and holding time have a significant effect on the size distribution and average size of prior austenite grains.
Materials today communications
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
216 Materials engineering
The authors would like to thank Finnish Foundation for Technology Promotion for their financial support during this work through the program of postdoc in company (PoDoCo). Also, part of this work was conducted within the framework of the AMET project funded by Business Finland. Oskari Seppälä would like to acknowledge financial assistance of Business Finland, project FOSSA- Fossil-Free Steel Applications.
© 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).