Establishment of methodologies for characterization of intergranular corrosion of stainless steels
Liew, Yan Han
Date of Issue2016
School of Materials Science and Engineering
Singapore Institute of Manufacturing Technology (SIMTech)
Intergranular corrosion (IGC) in austenitic stainless steel is a common and severe issue during welding and high temperature usage. Hence, using austenitic stainless steel as a start, the various IGC standard tests were evaluated. This includes the American Society for Testing and Materials (ASTM) A262 and ASTM G108 international standards. This is followed by the establishment of methodologies for these standards, paving the way to greater capabilities in IGC characterization for the industries in Singapore. With the establishments, a more detailed analysis on a variety of differently conditioned AISI 304 & AISI 304L grade stainless steels was done. A few important areas were investigated, such as the influence of low carbon grade AISI 304L and critical parameters for solutionizing. At the same time, the correlation and reliability of the standards were also evaluated. Issues regarding the assumption made in the calculation of results for G108 demonstrates that this is not a straightforward task of following an international standard. In-depth knowledge of the fundamentals and principles are required. A useful outcome of this project includes the qualitative and quantitative databanks of information, which will offer valuable data for future IGC evaluation and research. Ultimately, this project provides a good fundamentals for long-term research on IGC. Recommended future work includes looking into the corrosion mechanism involved in AISI 304L, investigating the existence of a critical size, shape or distribution of chromium carbide precipitates, or venturing into customizing the IGC evaluation tests for other materials.
Final Year Project (FYP)
Nanyang Technological University