Abstract
Stress corrosion cracking (SCC) is a potential risk in structural steels used for steam boilers. To investigate the effect of dissolved oxygen (DO) on SCC susceptibility, three steels, T23, T24 and T91 were annealed at 1065°C and then quenched to create a susceptible microstructure and then exposed in a Jones test to stagnant and circulating water at 200°C with varying DO levels. The results indicated that among the tested steels, the SCC susceptibility was highest in T91 but lowest in T23 which did not exhibit crack initiation with 100 ppb DO. T24 showed no cracking with 50 ppb DO but cracked with 100 ppb DO under these conditions. Based on these results, the next planned step is to monitor crack growth in-situ and determine a critical DO content for each material.
