"Hot rolling is a manufacturing process that involves large material deformation, complicated geometries, contact conditions and non-uniform temperature gradients. Steel industries are motivated to prevent hot rolled steel products to be defect free and with desired shape and size. In order to simulate the process accurately, it is essential that the material model for steel accounts for the viscoplasticity and changes in properties that occur in steel at elevated temperatures as grain growth and recrystallization.
The healing of existing voids during hot rolling was investigated using finite element simulations. Voids are highly undesirable as they not only degrade the product quality but also serve to initiate cracks and fissures. During rolling most of the voids are expected to close due to deformation of the rolled material at high temperature. The influence of various rolling parameters on void closure were predicted using simulations.
During multi-pass hot rolling of steel microstructural changes occur due recrystallization and temperature. Elevated temperatures result in grain coarsening, while recrystallization triggers grain refinement. The parameters governing the static recrystallization kinetics were determined using the double hit compression test. Various steel grades were characterized to determine the change in grain size at elevated temperature. The effect of grain size on the flow stress was also found using a set of experiments. These findings helped to create a new plasticity model based on the classical Johnson-Cook model that included the influence of grain size on the flow stress and static softening due to recrystallization"--Abstract, page iv.
O'Malley, Ronald J.
Dharani, Lokeswarappa R.
Midha, A. (Ashok)
Mechanical and Aerospace Engineering
Ph. D. in Mechanical Engineering
Peaslee Steel Manufacturing Research Center
Missouri University of Science and Technology
Journal article titles appearing in thesis/dissertation
- Modeling and simulation of void closure during Steckel mill rolling for steel plate
- Modeling and simulation of mass flow during hot rolling low carbon steel I-beam
- A modified Johnson-Cook model incorporating the effect of grain size on flow stress
- Modeling and static recrystallization kinetics of high strength steel during multi-pass hot rolling
xv, 121 pages
© 2021 Shouvik Ganguly, All rights reserved.
Dissertation - Open Access
Ganguly, Shouvik, "Thermomechanical simulation and process optimization for hot rolling of steel" (2021). Doctoral Dissertations. 2971.