(502d) Tensile Properties and Corrosion Susceptibility of Alloy C - 276 in S - I Environment

The tensile properties of Alloy C 276, a leading candidate structural material for heat exchanger applications, have been determined at temperatures ranging from ambient to 600°C at a strain rate of 10-3 / sec. The results indicate that both the yield strength and ultimate tensile strength of this alloy were gradually reduced with increasing temperature, as expected. However, the ductility in terms of percentage elongation was reduced at 200 and 450°C. The results of stress corrosion cracking (SCC) tests involving this alloy in a simulated acidic solution, containing sulphuric acid & sodium iodide (S-I) revealed no failure at a constant load. SCC testing under a slow-strain-rate condition showed reduced failure stress at an elevated temperature, with insignificant variation in the ductility parameters. As to the general corrosion behavior, this alloy showed very little weight loss in a similar environment. The fractographic evaluation of the primary fracture surface of the tensile specimens revealed dimpled microstructures, indicating ductile failure.