Effect of S addition on mechanical and machinability properties in austenitic Fe–Mn–Al–C lightweight steels

Abstract

In this study, the machinability of austenitic LWS and the effect of MnS formation on the mechanical and machinability properties were investigated. For this purpose, S was added over a wide range from 0.0048 to 0.0713 wt% to control MnS inclusions. As the S content increased, the number and area fraction of the MnS inclusions increased linearly, whereas the inclusion size first rapidly increased, and then its slope decreased. The tensile properties hardly changed regardless of the S content, whereas the Charpy impact energy deteriorated linearly with increasing S content. Furthermore, the machinability of LWS was considerably improved by the formation of MnS inclusions, which play a role in the site of mechanical stress concentration and thermal cavity and pore generation during machining.