Environmentally assisted crack growth in one-dimensionally cold worked Alloy 690TT in primary water

Abstract

Environmentally assisted crack growth in thermally treated Alloy 690 cold worked one-dimensionally to the thickness reduction of 25% in primary water was investigated. In the water at 50°C and dissolved hydrogen (DH) of 2.7–2.9ppm, the alloy showed a crack growth rate of <2.2×10−9mm/s at a stress intensity factor of 35MPa√m. In the water at 340°C, stress corrosion crack growth rate of <1×10−8mm/s was observed in the alloy over a DH range of 0.37–2.6ppm. Further, it was found that hydrogen could promote SCC growth when increasing DH from a very low level.