The Dynamic Recrystallization of Hot-Deformed Austenite in a Micro-Alloyed Steel

Abstract

As the dynamic recrystallization (DRX) behavior of hot-deformed austenite is the basis of determining controlled rolling schedule for steel, in the present work, the dynamic recrystallization behavior of austenite of a 0.22%C-1.30%Mn-0.04%Nb micro-alloyed steel was investigated by means of high temperature compression tests on the Thermecmastor-Z simulator. By the analysis of true stress-strain curves at different deformation stages, the hot deformation equation of austenite was established for the steel. As a result, the energy to induce recrystallization of austenite for the steel is 419.1 kJmol-1, as it was influenced by the drag effect of micro-alloyed element Nb in solid solution. The ratio (σc/σp) of critical stress σc (where DRX occurs) to peak stress σp is 0.93 while the ratio (εc/εp) of critical strain εc to peak stress εp is 0.52 for the steel. The austenite grain size of dynamic recrystallization of the micro-alloyed steel is refined by decreasing the deformation temperature and improving the stain rate.

Archives of Metallurgy and Materials

“…Increasing stress relief temperature from 950 to 1150°C decreased peak stress, which is related to the dynamic recrystallization kinetics due to temperature rising (Fig. 9) [8]. The identification image and EDS analysis of the intended precipitate by scanning electron microscopy (SEM) is shown in Fig.…”

“…2 and Fig. 3, with an increment in the strain rate and decrement in the deformation temperature, the flow stress and peak stress have enhanced in the stress-strain curves due to the postponement of the dynamic recrystallization [8]. The decrease in the temperature of hot deformation decreased the recrystallization rate and increased the work hardening [8,14].…”

“…Badjena and Park illustrated that Al-V-N micro-alloyed steel accelerated dynamic recrystallization [7]. She et al investigated hot deformed Mn-Nb micro-alloyed steel in order to determine the controlled rolling of steel parameters [8].…”

“…Many researchers have worked on stress relaxation on micro-alloyed steel as well [10][11][12][13]. By calculating the activation energy of hot deformation and comparing it with austenite lattice self-diffusion activation energy [5,8], the effect of carbonitrides on dynamic recrystallization can be understood.…”