Abstract- Duplex stainless steels (DSS) which comprise dual microstructure consisting of phase balance of austenitic
phase ('y phase) and ferritic phase (a phase) have been an area of interest for researchers, stainless steel producers, fabricators
and end users. This paper gives a brief review on low temperature surface heat treatment processes of nitriding,Carburizing and nitrocarburizing on DSS by surface engineering techniques of thermochemical heat treatment which typically performed by introducing carbon and/or nitrogen elements to produce hard layer expanded austenite on the surface layer performed below 500 °C. The formation of expanded austenite/ expanded layer is important to achieve enhanced surface hardness and wear resistance,without compromising their corrosion resistance. The comparisons of characteristics of each process is discussed and prospect on performing heat treatment on DSS is briefly
discussed.