In a recent work,1 the susceptibility to the intergranular corrosion of Alloy 800 has been examined in some low carbon laboratory-scale heats, aged in the temperature range 500 to 650 C for times up to 2000 hours. These heats, solution annealed at 1010 C, presented an average grain size between 30 and 35 microns (ASTM GS6.5). The time temperature-sensitization diagrams, obtained with the ASTM A 262 Practice E, depended on the titanium concentration; the carbon concentrations being nearly constant (about 300 ppm). A computer simulation, based on an improved chromium depletion theory, was found to describe the TTS behavior in good agreement with the experimental data. The only varying input parameter in the TTS computation was the initial titanium level in the alloys.
In the present work, the TTS behavior of three different heats of Alloy 800 (aged in the range 525 to 650 C, up to 1000 hours)...
