Abstract
Carbide free nano-bainitic (NSB) steels have a dual phase structure comprising of retained austenite (RA) and bainitic ferrite (BF). The content and morphology RA and BF in NSB steels can be easily modulated by changing the austempering temperature. This results in significant changes in the strength and is expected to influence the corrosion resistance as well. The corrosion behavior of three NSB steel blocks austempered at 250, 300 and 350 °C has been studied in aqueous chloride (3.5 wt% NaCl) environment. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization have been used to investigate the role of austempering temperature on the corrosion response. It is found that the corrosion current density and hence the corrosion rate decreases with a reduction in austempering temperature. Moreover, a reduction in the austempering temperature shifts the corrosion potential towards the nobler side. The EIS studies have shown that the charge transfer resistance gets enhanced for specimens austempered at lower temperatures. This comes with a concomitant lowering in the capacitance of the electrical double layer formed between the steel specimen and electrolyte. Thus, it is possible to achieve a combination of high hardness and corrosion resistance by fabricating the NSB steels at low austempering temperatures.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
