Electrochemical and Microstructural Investigation of Grain Boundary Precipitation in AISI 304 Stainless Steels Containing Nitrogen

Microstructural characterization of δ/γ/σ/γ2/χ phases in silver-doped 2205 duplex stainless steel under 800 °C aging

“…Because the element N was not the stabilizer of ferrite, the numerous undissolved N element are provided from the ferrite [18]. In addition, the element N possesses better affinity to Cr than the element C [19], wherefore the elements N and Cr easily react with each other and precipitate to form Cr 2 N. Due to the formation of Cr 2 N at the δ/γ grain boundaries, Cr concentration in ferrite was decreased by diffusing toward δ/γ grain boundary to induce ferrite transform to γ 2 phase. Furthermore, the γ 2 -phase continuous growth process needed austenitic stabilizers (Ni, Cu and Mn) to supply reaction of δ→γ 2 .…”

Time–temperature-sensitization diagrams and critical cooling rates of different nitrogen containing austenitic stainless steels

“…Controversial opinions exist among various authors on the threshold nitrogen % up to which the beneficial effect with respect to sensitization is observed [15][16][17][18][19]. In other words, in austenitic stainless steels, the effect of nitrogen on the sensitization process is not clearly understood.…”

Effect of nitrogen content in sensitised austenitic stainless steel on the crack growth rate in simulated BWR environment

“…Presence of nitrogen in austenitic SS has been reported to affect the IGSCC susceptibility to a large extent. Mozhi et al [29,61,62] have reported that presence of nitrogen to the extent of 0.16 wt.% in austenitic type 304 stainless steels increases the SCC resistance and reduces it when nitrogen level increases further. Nitrogen addition in austenitic type 304 stainless steels retards the sensitisation kinetics as for a constant carbon level, the grain boundary chromium concentration in equilibrium with the carbide increases with increasing nitrogen content.…”