Possibility of Using Direct Current Potential Drop for Stress Corrosion Cracking Life Assessment

Abstract

The standard tests for degree of sensitivity in Stainless Steel grade 304 are ASTM A262 and % DOS utilizing the DL-EPR technique. However, these methods are limited by their low resolution and challenges in classifying DOS when the grain boundary is particularly susceptible to corrosion. The direct current potential drop (DCPD) technique was used to determine the potential drop in solutionized specimens. These experimental specimens were sensitized by heating them at 650 °C for 1–32 h. The results reveal that the ASTM A262 showed microstructure examination for aging times greater than 2 h, and the sensitization was classified as just ditch structure. When DCPD was compared to DL-EPR, the potential drop initially dropped and then climbed to a high of 91.88 μV–96.83 μV and 78.32 –75.49 μV for solutionized specimens. At the same time, the DL-EPR technique’s DOS gradually increased, peaking at 40.86%. Nevertheless, due to the insufficient resolution to show a change in intergranular corrosion at the grain boundary, DOS stayed within the usual range of 38.82%. Conversely, the potential drop technique showed a steady decline, with the as-received and solutionized specimens showing 73.34 μV and 69.53 μV, respectively, as a result of the increased iron proportion in the matrix brought on by chromium replacing iron in the precipitated carbide. The outcomes demonstrated the benefit of employing the DCPD in comparison with conventional methods. It could also be used to determine the possibility that a crack would occur from stress corrosion cracking.