Microstructural Evolution and Mechanical Properties Co relation of Cold rolled Ferritic Lightweight Steel with Increasing Carbon

Abstract

The structure-properties relationship of cold-rolled and annealed Fe-7wt.%Al lightweight steels for varying carbon contents is explored in this work.Unlike Fe-Mn-Al-C based steels, which experienced processing issues, the hot-worked plates of the present steel were successfully cold-rolled to 2mm thick sheets. Various phases present in the steel for different carbon contents as predicted using the ThermoCalc programme are in line with the experimental findings. The basic alloy with 0.01C contains only a ferrite phase, however, the alloys with  higher carbon content  have a significant quantity of κ-carbide precipitates. The addition of carbon to Fe-7wt.%Al steel has improved its  tensile strength significantly (438 to 828MPa). Tensile elongation, on the other hand, has decreased dramatically (26 to 12 percent) with increasing carbon content The reduction in ductility with increasing carbon is mainly ascribed to the increasing κ-carbide  precipitates volume fraction with higher hardness, but not due to the environmental embrittlement as observed in case of higher Al containing steels.