Study of SCC Susceptibility of Sensitized SUS 304 Steel in High Temperature Water and Effect of Synthetic Weld Thermal Cycles on its Sensitivity

Abstract

SCC susceptibility of sensitized SUS 304 stainless steel in high temperature water was studied. The results are as follows.
SCC susceptibility was increased by adding crevice to tensile specimen surface, for the corrodent being to acidify by hydrolysis in crevice. SCC susceptibility was best fit to TTS curve gained by EPR test than other corrosion tests such as Strauss test and grain boundary corrosion test in high temperature water. In addition, giving synthetic weld thermal cycle before the sensitizing heat treatment, the sensitization was considerably promoted. This would be caused that nucleation of carbide was occurred in synthetic weld thermal cycle process and the carbide growth and chromium depleted zone formation around the carbide were promoted in following sensitization process.