Chloride-Induced Stress Corrosion Cracking of Oxide-Dispersion-Strengthened Austenitic Steels

Abstract

The stress corrosion cracking (SCC) behavior of oxidedispersion-strengthened (ODS) 304 austenitic steels has been investigated in a chloride-rich aqueous environment at 143°C. ODS 304 alloys are found to be more resistant to SCC than the commercial AISI 304 steels. Under a constant tensile load of 177 MPa, the crack growth rate in ODS 304 steels is about one fourth of AISI 304 steels, and the time-to-failure of ODS 304 steels is 7.5 times of AISI 304 steels. Intergranular SCC dominates the fracture surface of AISI 304 steel, while in ODS 304 steel both intergranular and transgranular SCC occur. Electrochemical reactivity tests show ODS 304 steel is less sensitized than AISI 304, likely a result of a low carbon concentration and small grain size.