Best ways to prevent SCC in chemical process industries

More than 140 SCC failures mainly occurred in chemical process industries have been analyzed for last 30 years and research works to establish engineering preventive measures for representative SCC have been also conducted. Until about 15 years ago, more than 30% of all materials failures, which were asked to be solved by the materials engineering section of an engineering contractor, had been SCC. In the last 5 years, SCC failures have been 10 percent. The background behind this is that some preventive measures against SCC would now be taken at the designing stage. In this paper, the importance of studying technical information of SCC from field sites and the SCC laboratory data at the same table will be discussed based on 2 cases, that is, polythionic acid SCC on stabilized stainless steels and amine SCC on carbon steels. In addition, the predicting method for chloride SCC on 300 series SS in heat exchangers will be also proposed.