Stress Corrosion Cracking of Sensitized Stainless Steel in Oxygenated High Temperature Water

The stress corrosion cracking (SCC) behavior of sensitized Type 304 stainless steel has been studied in 288 C (550 F) primary water as a function of oxygen and fluoride contents of the water, stress level, prestrain, heat treatment, and surface preparation (tarnish film, surface ground, or pickled). Susceptibility to intergranular cracking increased with increasing oxygen content in the water, increasing stress levels, or with tarnished or pickled surfaces. The other variables had little or no effect. Sensitized wrought Types 309 and 316 stainless steels were also susceptible to intergranular SCC, while sensitized Types 304L, 308L, and 347 stainless steels and Incoloy Alloy 800 and Inconel Alloy 600 did not crack under the most severe test conditions (3Sm stress loading in 288 C water containing 100 ppm oxygen).