Interacting sensitivities of alloy 600 PWSCC to stress intensity factor, yield stress, temperature, carbon concentration, and crack growth orientation Alloy 600

Analyses of Alloy 600 primary water stress corrosion cracking data show there are interacting sensitivities of crack growth rate to applied stress intensity factor, yield stress, temperature, carbon concentration and crack growth orientation. The effects of these variables are expressed quantitatively using a crack advance model that is rate-limited by crack-tip-strain rate. Crystallographic texture and dynamic strain aging are considered to account for contrasting behavior observed for ST and LT orientation crack growth. Crack growth is conjectured to be rate-limited by “junction” pinning of mobile dislocations strengthened by interstitial carbon (ST) and “lineal” pinning by substitutional Cr and Fe (LT).