Microstructure and tensile properties of hot-rolled Fe-C-Mn-Si-Cu multiphase steel

Cu-containing Fe–C–Si–Mn multiphase steel was fabricated by hot rolling. The microstructure of the steel becomes more homogeneous and the type of hard second-phase changes to martensite from bainite with increasing quench-finish and coiling temperatures. The precipitation of Cu-related phases is promoted by an increase in quench-finish temperature. The steel with fine distributions of particles consisting of martensite and retained austenite within the e-Cu-containing ferrite matrix shows the best combination of strength and ductility.