Physical Simulation of the Hot Direct Rolling of Steel

Abstract

Thin slab casting and direct rolling technologies became important for hot strip production to increase the productivity, to lower the investment costs and to increase the energy efficiency. The main objective of our investigation is to gain a better understanding of the microstructural evolution starting from solidification through to the final hot rolled sheet. Small ingots were cast and direct rolled and reheated and rolled, using a thermomechanical testing machine. The differences in the recrystallization kinetics during both production routes were measured using double hit hot compression tests. In addition, multipass deformation trials were performed to reveal differences in the resulting microstructure and the grain size homogeneity. It was found, that the coarse initial microstructure before rolling become negligible after three rolling passes. This means that despite the simple and economical direct rolling similar mechanical strip properties can be obtained in comparison to conventional strip production routes.

Effect of Twinning on Microstructural Evolution During Dynamic Recrystallisation of Hot Deformed As-Cast Austenitic Stainless Steel

“…There is increasing interest in the understanding and modeling of microstructure evolution during DRX. [1] There are different nucleation mechanisms for single-phase polycrystalline materials that control recrystallization. The first is the bulging of pre-existing boundaries characterized by migration of pre-existing high-angle grain boundaries.…”

The Influence of Hot Charging Conditions on Microstructure and Precipitation of High Strength Nb–Ti Complex Microalloyed Steels

“…The grain size is more refined at 700°C compared with that higher than 700°C since the γ → α phase transformation has occurred. The γ → α transformation during cooling down to 700°C results in a significant finer grain structure, the schematic illustration of the as cast austenite microstructure in comparison with the microstructure after γ → α transformation is shown in Figure 3 8…”

Influence of the Microalloying Elements on the Temporary Inhibition of Static Recrystallization by Strain-Induced Precipitates

“…The deformation temperatures were between 1150 and 800°C and the recrystallized fraction was determined for several post‐deformation holding times. The double deformation technique was used to calculate X a , in particular applying the method known as “back extrapolation” . The accuracy of this method has been verified by comparing with metallographic observations .…”