Investigating the Impact of Initial Microstructure on IQP Processing of Medium-Mn Steel with Mn Segregation Banding

This article presents the design and preparation of two distinct initial microstructures in medium-Mn steel, both of which retain Mn segregation banding. The specific composition of the steel is Fe-0.25C-3.08MN-1.5Si-0.054 Nb, wt%. To facilitate a comparative study under the IQP process, ingots of 25 kg laboratory smelted steel were reheated to approximately 1200 ﾰC for 1 hour and hot rolled to 4.5 mm. Rectangular specimens were then machined from the cold rolled sheets, measuring 1.5 mm in thickness, parallel to the rolling direction.

Heat treatment experiments were conducted on a continuous annealing simulator, with varying intercritical annealing temperatures and quenching temperatures tailored for each sample. The article also delves into another initial microstructure obtained after cold rolling, which underwent the same treatment regimen.

The research focuses on investigating the impact of these distinct initial microstructures on the subsequent IQP process, emphasizing the role of different annealing and quenching parameters in controlling the final microstructure and properties of the medium-Mn steel.