The effect of potential on the susceptibility to stress corrosion cracking (SCC) of Type 316L stainless steel (SS) \[UNS $31603\] and Alloy 22 \[UNS N06022\] was determined in hot, concentrated chloride solutions using precracked compact tension (CT) specimens. In the case of Alloy 22, constant deflection tests using single and double U-bend specimens were also conducted in hot, acidified and supersaturated PbC12 solutions. It was found that Alloy 22 is very resistant to crack initiation and propagation at an initial stress intensity of 47 MPam 1/2 \[43 ksi'in 1/2\] in 9.1 molal LiC1 solution at 95 °C \[203 °F\], confirming previously reported results. No crack growth was observed even when cyclic loading at a frequency of 0.001 Hz and a R ratio (R = Kimin/Kimax) of 0.7, with Klmax - 47 MPa'm 1/2 \[43 ksi'inV2\], was applied. Also, no SCC was detected in the chloride solutions containing lead species, even for thermally aged specimens. On the contrary, relatively fast crack growth was observed on Type 316L SS specimens in 9.1 molal LiC1 solution at 95 °C \[203 °F\] when the potential was above the repassivation potential for crevice corrosion, even at a stress intensity of 20 MPam 1/2 \[18 ksi'inl/2\].
Keywords: Stress corrosion cracking, localized corrosion, stainless steel, nickel base alloys, nuclear waste disposal