Criteria for prediction of plastic instabilities for hot working processes: Part II. Characterization of plastic flow of medium carbon microalloyed steel using phenomenological and continuum criteria

Abstract

In the study of hot working processes, the knowledge of interaction between microstructural behaviour and control process parameters such as temperature, strain rate, and strain is very important. In the last decades, processing maps have been developed to design, control, and optimize the hot strain of various metallic materials. In this work, to study the hot workability of medium carbon microalloyed steel, during hot compression tests, a comparative study between two types of processing maps constructed using phenomenological and thermodynamic continuum criteria has been carried out. The analysis of the maps indicates that the studied steel does not undergo any type of plastic instability. However, the maps corresponding to the strain of ϵ = 0.6 reveal a domain of dynamic recrystallization, considered as the more efficient domain within the ‘safe’ region process. This domain is centred at 1150°C and 10 s^− 1. Also, the comparative study of the obtained results shows the difference between the positions of plastic strain domains predicted by the two criteria.

Keywords:

• hot working
• microalloyed steel
• plastic instability maps
• dynamic recrystallization
• flow localization

Acknowledgements

One of the authors, Anas Al Omar, wishes to thank the CICYT (Spain) for its financial support through the project DPI2007-63665.