Synchrotron X-ray fluorescence imaging study on chloride-induced stress corrosion cracking behavior of austenitic stainless steel welds via selective corrosion of 6-ferrite

Chloride-induced stress corrosion cracking (CISCC) is a degradation of austenitic stainless steels by Cl-containing media, residual stress, and materials susceptibility. In this study, synchrotron X-ray fluorescence imaging and electron microscopy were utilized to investigate the CISCC mechanism in austenitic stainless steel welds 304 LER308L and 316 L-ER316L. Specimens were exposed to 60 degrees C and 30% relative humidity conditions for 3 months and their microstructure and chemistry were analyzed. Since 6-ferrite is composed of ferrite formers especially Cr and acts as a sink for impurities, selective corrosion of 6-ferrite results in pitting corrosion and CISCC propagation.

Automated summary

Chloride-induced stress corrosion cracking (CISCC) is a degradation phenomenon in austenitic stainless steels caused by Cl-containing media, residual stress, and materials susceptibility. In this study, synchrotron X-ray fluorescence imaging and electron microscopy were used to investigate the CISCC mechanism in austenitic stainless steel welds 304 LER308L and 316 L-ER316L. Specimens were exposed to 60 degrees C and 30% relative humidity conditions for 3 months, and their microstructure and chemistry were analyzed. Selective corrosion of 6-ferrite, which is composed of ferrite formers especially Cr and acts as a sink for impurities, leads to pitting corrosion and CISCC propagation.