Programma in fase di definizione. I titoli degli interventi e i nominativi dei relatori saranno progressivamente aggiornati.
- Materials degradation of austenitic stainless steels AISI316 in caustic environments: causes and mitigation approaches (E. Coscia - SYENSQO)
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A corrosion damage case occurring in caustic service at the SYENSQO site in Spinetta Marengo was investigated to determine the root cause, confirm the degradation mechanism and define suitable corrective actions. The affected equipment, operating under alkaline process conditions, showed localized cracking and material deterioration consistent with a progressive damage scenario. A structured damage-analysis workflow was implemented, combining on-site inspections, non-destructive testing (NDT) and laboratory characterization. The field assessment prioritized NDT techniques capable of detecting and sizing crack-like indications and supporting the confirmation of stress corrosion cracking (SCC). Visual examination and surface preparation were followed by liquid penetrant testing for surface-breaking indications. Where geometry and access allowed, complementary inspection approaches (e.g., replicated surface metallography) were applied to correlate crack morphology with local metallurgical condition and operating stresses.
Representative samples were then analyzed in the laboratory through metallographic cross-sections and microstructural examinations to characterize crack features (branching, intergranular/transgranular path, secondary cracking) and to differentiate SCC from alternative damage modes such as fatigue or fabrication-related defects. The combined evidence supported a caustic-environment cracking mechanism affecting the in-service alloy under the specific process conditions. Based on the confirmed damage mechanism and the operating window, a materials selection activity was performed to identify a more compatible alloy for caustic service. Candidate materials were screened against corrosion/SCC resistance in alkaline media, fabrication and weldability constraints, mechanical requirements, and availability. The study concludes with a proposed material upgrade and inspection/monitoring recommendations to reduce recurrence risk and improve long-term asset integrity.