Stress Corrosion Cracking of SUS304 Stainless Steel in High Temperature Water : Effect of Dissolved Oxygen and Strain Rate(Materials, Metallurgy & Weldability)

概要

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This study was made to investigate the effects of dissolved oxygen, strain rate and solution treatment temperature on the stress corrosion cracking (SCC) of the sensitized SUS 304 stainless steel. For the specimens solution-treated at 1373K, the higher IGSCC susceptibility was attributed to Cr-depleted zone and the segregation of impurities in the high temperature water with dissolved oxygen. However, in the deaerated water, the IGSCC susceptibility decreased. As the solution treatment temperature increased, the degree of sensitization evaluated by Strauss test decreased owing to narrow Cr-depleted zone. In a slow strain rate test (SSRT), IGSCC susceptibility increased with the decrease in the strain rate in dependent of the solution treatment temperature. But, for the specimens solution-treated at 1573K, SSRT results were not correspondent with the results by Strauss test, that is, SSRT was a severe test compared with corrosion tests such as Strauss test. It was found that the electrolytic conductivity of high temperature water in SSRT was higher on sensitized specimens than that of solution-treated specimens. This increase in the electrolytic conductivity seems to be related to the pit formation at the grain boundaries of the sensitized specimens.
大阪大学の論文