Hot Deformation Behavior and Processing Maps of a Medium Manganese TRIP Steel

Abstract

The hot deformation behavior of a medium-Mn steel was studied in terms of hot compression flow curves in the temperature range of 850-1050°C and strain rates of 0.05-10 s-1. The thermo-mechanical analysis was carried out and suggested that the microstructure during deformation was completely austenite which had high tendency for dynamic recrystallization (DRX). The flow behavior was characterized by significant flow softening at deformation temperatures of 950-1050°C and lower strain rates of 0.05-5 s-1 , which was attributed to heating during deformation, DRX and flow instability. A step-by-step calculating procedure for constitutive equations is proposed. The verification of the modified equations indicated that the developed constitutive models could accurately describe the flow softening behavior of studied steel. Additionally, according to the processing maps and microstructure analysis, it suggested that hot working of medium-Mn steel should be carried out at 1050°C, and the strain rate of 0.05-10 s-1 resulted in significantly recrystallized microstructures in the in steel. The flow localization is mainly flow instability mechanism for experimental steel.

Microstructure evolution and static recrystallization kinetics in hot-deformed austenite of coarse-grained Mo-free and Mo containing low-carbon CrNiMnB ultrahigh-strength steels

“…For both steels, the flow stress decreases as the deformation temperature increases. This is due to a decrease in work hardening because of decreased dislocation motion resistance [25]. Compared to 0Mo steel, the addition of Mo increases the flow stress throughout all deformation temperatures.…”

Effect of Grain Size and Compression Direction on the Hot Deformation Characteristics of High-Cr Ultra-Super-Critical Rotor Steel with Columnar Grains

“…The load uner PRCD directly acts on the columnar grain boundaries, while promotes the generation of deformation bands under PPCD. The more grain boundaries and deformation bands provides the nucleation sites of DRX grains [ [18], [19]]. The broken δ-ferrite along the columnar grain boundaries is discontinuous, which is attributed to the brittleness of δ-ferrite.…”

Research on hot deformation behaviour of as-cast W12Cr4V5Co5 steel

“…Then, as the strain unceasingly advances, the stress gradually decreases and eventually approaches a stable state. The reason for this phenomenon can be explained as follows [19][20][21]: When the experimental alloy is plastically deformed at the initial stage, the interaction between dislocations increases with the increase of dislocation density, which hinders the dislocation movement, causing a sharp increase of flow stress. The continuous increase of deformation will induce the occurrence of dynamic recrystallization at some point, which is why the work hardening rate retarded, and in the process, distortion energy acts as a driving force.…”