Correlation between cementite precipitation and Portevin-Le Chatelier effect in a hot-rolled medium Mn steel

The correlation between cementite precipitation and plastic instability phenomena especially Portevin-Le Chatelier (PLC) effect was investigated for a hot-rolled medium Mn steel. The microstructure demonstrated lamellar morphology of austenite and ferrite. Cementite precipitations could be retained by controlling certain intercritical annealing (IA) process. The initial high density of dislocations in ferrite contributed to the continuous yielding. Cementite precipitations lowered solute carbon content in ferrite and the dynamic interaction with dislocations was eliminated. A moderate product of strength and elongation (PSE) grades hot-rolled medium Mn steel without PLC effect during tensile test was obtained by controlling the IA process. (C) 2019 Elsevier B.V. All rights reserved.