Intergranular Stress Corrosion Cracking Resistance Research Articles

Microstructure and stress corrosion resistance of alloys X750, 718, and A286 in light water reactor environments

The results of microstructural characterization and stress corrosion cracking tests are presented for several heat treatment conditions of the age-hardenable Alloys X750, 718, and A286. Resistance to intergranular stress corrosion cracking (IGSCC) was evaluated using slow strain rate tests in pressurized water reactor (PWR) primary water, microstructural etch, and rising-load screening tests. The results of these tests indicate greater IGSCC resistance in the PWR primary water environment for X750 microstructures with heavier grain boundary coverage by Cr23C6, regardless of grain boundary chromium depletion. Alloys 718 and A 286 were not highly SCC susceptible according to these screening tests, although they are not immune to IGSCC in reactor environments. Results are compared with those of a related program, including crack initiation and crack growth tests in pressurized and boiling water reactor (BWR) environments.

Technical Note:Influence of Silicon on the Intergranular Stress Corrosion Cracking Resistance of 18Cr-8Ni Base Stainless Steel

<b><i>Technical Note:</i></b>Influence of Silicon on the Intergranular Stress Corrosion Cracking Resistance of 18Cr-8Ni Base Stainless Steel

Effect of Heat Treatment Applied Potential on the Caustic Stress Corrosion Cracking of Inconel 600

Abstract The stress corrosion cracking (SCC) behavior of differently heat-treated specimens of Inconel 600 in 25 molal (m) NaOH solution at 140 C was studied as a function of potential by using the slow strain rate technique (SSRT). It was found that the cracking susceptibility and the failure mode (intergranular vs transgranular) depends heavily on potential, heat treatment, and grain size. In the mill-annealed condition, intergranular stress corrosion cracking (IGSCC) was obtained at potentials extending from the active peak (−900 mVSCE) to the secondary anodic peak (−400 mVSCE), while transgranular stress corrosion cracking (TGSCC) occurred at the open circuit potential (OCP), ∼−980 mVSCE, and at 0 mVSCE (secondary passive region). Solution-annealed material showed reduced IGSCC susceptibility with respect to the mill-annealed material, while almost complete IGSCC resistance was obtained by heat treatment at 700 C of both mill- and solution-annealed materials. Also, material with small grain size exhib...

Comparative Stress Corrosion Behavior of Welded Austenitic Stainless Steel Pipe in High Temperature High Purity Oxygenated Water

Abstract An alloy for boiling water reactor (BWR) welded pipe applications that is not subject to intergranular stress corrosion cracking (IGSCC) has been qualified for service in high purity high temperature oxygenated water. This alloy provides extra margin against cracking as compared to reference Type 304 stainless steel. Several commercially available alloys were studied in the form of welded 4 inch (10 cm) diameter schedule 80 pipe. Basic resistance to IGSCC was evaluated utilizing cyclic load stress corrosion tests conducted on 4 foot (1.2 m) lengths of welded pipe. Once the basic IGSCC resistance was established, the corrosion fatigue resistance of the alloys was evaluated to verify the adequacy of the ASME Code fatigue design curve. Results of all the testing were analyzed in terms of a model that considers chemical composition, degree of sensitization, stress and phases present. The two optimum alternate alloys were selected.