Experimental Investigation and Mathematical Modeling of Dynamic Recrystallization Behavior of Nb microalloyed Steels

摘要

Isothermal single compression tests were performed on three Nb microalloyed steels from 850 to 1150°C at constant strain rate (0.1-5s~(-1)) in order to investigate the dynamic recrystallization behaviour and predict the flow stress during plate rolling. The effects of deformation conditions and Nb content on the activation energy of deformation were thoroughly studied, and the quantitative relationship between the activation energy of deformation and Nb content was developed. The ratio of the critical strain to the peak strain decreases with increasing Nb content, from which an empirical equation was developed. In addition, the influence of Nb content and deformation conditions on the steady state grain size was determined. Finally, the flow stress of Nb microalloyed steels was accurately evaluated based on the one-internal-variable evolution equation by including the influence of DRX. The comparison between the experimental and theoretical results confirmed the validity of the modeling.