Low-temperature (below 500°C) interstitial treatment of corrosion-resistant alloys is a developing technology in surface engineering, resulting in performance enhancements in hardness and wear, corrosion-wear, fatigue and corrosion resistance. When applied to austenitic stainless steels, the resultant surface treatment has been described as S-phase, or expanded austenite. Major advances in understanding the technology and its application to austenitic, ferritic, martensitic and duplex alloys have occurred since the last symposium on this topic, held in Pittsburg in October 2014. This program will serve as a "state of the art" meeting, bringing together researchers from universities and government agencies all over the world, as well as providers and end users of low temperature surface hardening techniques. Papers devoted to all aspects of research on low-temperature processes (gas, ion and plasma processes) for surface enhancement of Corrosion Resistant Alloys (Fe-, Ni-, and Co-based Cr-containing alloys, as well as Ti and other passive alloys) by interstitial hardening (carburizing, nitriding and nitrocarburizing) will be presented.