Effect Of Pre-Strain And Aging Heat Treatment On The Corrosion Behavior For 2205 Duplex Stainless Steel In 6% Fecl3 Solution

A 2205 duplex stainless steel (DSS) was pre -stretched to 5% and subsequently aged at 850 C for 0-120 minutes, to explore the effects of pre-strain and aging treatment on the corrosion behavior of the DSS in 6% FeC13 solution at 50 C for 72 hours. The microstructure, hardness and corrosion behavior of the pre-strained and aged DSS were investigated based on statistical data and physical metallurgy in comparison with the counterparts without pre -strain. The results showed that the sigma (a) phase precipitated firstly in 5-ferrite grain boundaries and then in 6-ferrite/y-austenite (61y) phases boundaries by consuming the volume fraction of 6-ferrite. The volume fraction of o- phase in the DSS with and without pre-strain increased with increasing aging times following a classical Johnson-Mehl-Avrami (JMA) relationship, and the kinetics of the precipitation of a phase was accelerated by pre -strain throughout the aging time of 60120 min. The hardness of the non-pre -strained DSS (NPDSS) was lower than that of pre -strained DSS (P-DSS) throughout 0-120 min at 850 C. The hardness of NP-DSS increased continuously with increasing aging time, and the hardness of P-DSS decreased firstly and then increased continuously with increasing aging time. The aged NP-DSS displayed a gradually serious pitting with increasing aging time, and the corresponding corrosion behavior of the aged PDSS exhibited pitting firstly and then mainly cracking, and the pitting occurred in the vicinity of olo- and ylo- boundaries.