Estimating localised corrosion resistance of low alloy stainless steels: comparison of pitting potentials and critical pitting temperatures measured on lean duplex stainless steel LDX 2101 after sensitisation

摘要

Two different methods for estimating the corrosion resistance of low alloy stainless steels are compared: critical pitting temperature according to a modified ASTM G150 with a low chloride concentration (0.1M), and pitting potentials from polarisation curves acquired using the hovel Avesta multicell. The methods were tested on the lean duplex stainless steel grade LDX 2101, which has a corrosion resistance in the low end of the standard critical pitting temperature scale. The results from both methods correlated well with Charpy V impact energies and with the formation of carbides and intermetallics in the microstructure after annealing. In this study, the most consistent results for the sensitised material were obtained using pitting potentials.