Various microstructures of Alloy 690 and types of cold work were tested in representative pressurized water
reactor primary water at 290 to 360°C. Intergranular cracking was observed on Alloy 690 at constant stress
intensity factor (no cycling) and with “gentle” cyclic loading, but not in every case. Crack growth rates in some
tests were in the range of 1 to 10 x 10–9 mm/s, but growth rates as high as 7 x 10–7 mm/s were observed in Alloy 690 with microstructural banding and 1-dimension cold rolling tested in the S-L orientation, which aligns the planes of banding, rolling and cracking.
Keywords: Stress corrosion cracking, crack growth rate, high temperature water, Alloy 690, microstructural
banding, cold work, deformation