Magnetization study of the sensitization in SS304LN

• Published in: Materials research bulletin Vol. 109; pp. 149 - 154
• Main Authors: Sinha, Prerna, Chakravarty, Sujay, Singh, Raghuvir, Singh, P.K., G., V.S. Murthy
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2019
• Subjects: Degree of sensitization; Ferromagnetic; Magnetic; Sensitization; Stainless steel; Degree of sensitization; Sensitization; Magnetic; Ferromagnetic; Stainless steel
• ISSN: 0025-5408; 1873-4227
• DOI: 10.1016/j.materresbull.2018.09.028

Highlights •Sensitization of AISI 304 L N leads to the formation of a ferromagnetic phase due to the depletion of Cr in the Fe-Cr-Ni matrix resulting due to the formation of Ni-Fe matrix.•The magnetic behavior of the Ni-Fe matrix shows a complex behavior depending on the Cr-carbide layer thickness near the grain boundary.•The magnetic behavior has contributions from both ferromagnetic and paramagnetic or to be more particular super paramagnetic nature of the phase formed.•The blocking temperatures of the magnetic phase depend on the volume fraction of the Cr-depletion resulted from sensitization. At high enough values of DOS% these values are in the range of 200–250 K. [Display omitted] Sensitization is precipitation of chromium carbide in stainless steels during exposure to high temperatures service that leads to premature corrosion failure of components. It is well known that during sensitization process, chromium carbide forms at the grain boundary along with chromium depletion near the grain boundary resulting in the change of the magnetic property of the steel from paramagnetic to ferromagnetic. From this study, it is clear that the magnetic characterisation is sensitive enough to detect the sensitisation. However, the magnetic behavior has contributions from both ferromagnetic and super paramagnetic nature of the phase.