Atmospheric-Induced Stress Corrosion Cracking of Grade 2205 Duplex Stainless Steel—Effects of 475 °C Embrittlement and Process Orientation

Abstract

Abstract:The effect of 475˝C embrittlement and microstructure process orientation on atmospheric-induced stress corrosion cracking (AISCC) of grade 2205 duplex stainless steel has been investigated. AISCC tests were carried out under salt-laden, chloride-containing deposits, on U-bend samples manufactured in rolling (RD) and transverse directions (TD). The occurrence of selective corrosion and stress corrosion cracking was observed, with samples in TD displaying higher propensity towards AISCC. Strains and tensile stresses were observed in both ferrite and austenite, with similar magnitudes in TD, whereas, larger strains and stresses in austenite in RD. The occurrence of 475˝C embrittlement was related to microstructural changes in the ferrite. Exposure to 475˝C heat treatment for 5 to 10 h resulted in better AISCC resistance, with spinodal decomposition believed to enhance the corrosion properties of the ferrite. The austenite was more susceptible to ageing treatments up to 50 h, with the ferrite becoming more susceptible with ageing in excess of 50 h. Increased susceptibility of the ferrite may be related to the formation of additional precipitates, such as R-phase. The implications of heat treatment at 475˝C and the effect of process orientation are discussed in light of microstructure development and propensity to AISCC.

Characterization of 475°C Embrittlement of Duplex Stainless Steel Microstructure via Scanning Kelvin Probe Force Microscopy and Magnetic Force Microscopy

“…64 The majority of all larger precipitates were R phase (P 2 ,), which had significantly lower Volta potential differences than the other precipitates. 58 The width of their depletion zones was in the order of 50-100 nm. Carbides or secondary austenite have most likely formed a network along most interphase boundaries, as pointed out by P 1 and P 3 in Figure 10a.…”

Effects of Heat Input on Microstructure, Corrosion and Mechanical Characteristics of Welded Austenitic and Duplex Stainless Steels: A Review

“…DSS is not as resistant as ferritic SS but more resistant than austenitic against SCC [15]. The susceptibility of DSS to SCC depends on many factors, including alloying elements [120,121], microstructures [122,123], applied stresses [124,125], and environment [126][127][128][129].…”

Time-dependent in situ measurement of atmospheric corrosion rates of duplex stainless steel wires

“…The atmospheric corrosion performance of DSS has been studied as a function of strain, stress, and deposition density, and so far, a good understanding of the relationship of ferrite and austenite in DSS microstructures has been established. [28][29][30][31][32][33][34][35][36][37] However, CRs and SCC growth rates, in particular under atmospheric exposure conditions, have not been reported yet.…”