Effect of thermal aging at 475 °C on the properties of lean duplex stainless steel 2101

An investigation of the effect of thermal aging at 475 °C for up to 2000 h on the properties of a lean duplex stainless steel (LDSS) 2101 was conducted. Quantitative analyses of XRD based on Rietveld refinement revealed that the thermal aging did not affect the volumetric proportions of the ferrite/austenite phases present in the duplex microstructure. However, results from ferritoscope measurements showed a decrease in magnetic permeability of the ferrite after a prolonged exposure to 475 °C. In addition, the hardness of the ferritic phase increased significantly with the aging time and saturated after 600 h, resulting in a drastic decrease in Charpy impact energy. On the other hand, DL-EPR tests showed that the degree of Cr depletion (Qr/Qa) × 100 increased continuously as a function of the thermal aging at 475 °C for up 2000 h.