Influence of analysis, heat treatment and structure on susceptibility to intergranular stress corrosion cracking of nickel--chromium--iron alloys (Alloy 800 and Alloy 600)

From international nuclear industries fair; Basel, Switzerland (16 Oct 1972). Corrosion tests on a variant of Alloy 800 (Sanicro 30) in a modified Strauss solution have shown that the resistance to intergranular corrosion can be improved by a production sequence giving a small grain size and a high degree of stabilization. An investigation has also been performed in contaminated high- pressure water (100 ppM Cl/sup -//8 ppM O/sub 2/) on double U-bends of strip in Sanicro 30 and Alloy 600. This showed, for the inner U-bend in the crevice area, that the depth of intergranular attack depended on the type of low-temperature heat treatment. For Alloy 600 this was true also for the outside surface of the outer U-bend. The results from this investigation do not contradict the theory of a correlation between intergranular corrosion and intergranular stress corrosion cracking. (auth)