Correlation between critical pitting temperature and degree of sensitisation on alloy 2205 duplex stainless steel

In this study effect of different ageing conditions on intergranular corrosion, pitting corrosion and relation between critical pitting temperature (CPT) and degree of sensitisation (DOS) was investigated by potentiostatic polarisation and double loop-EPR methods. The results showed by increasing sensitisation time, DOS increased and measured CPT value decreased. In addition the values of DOS and CPT of specimens aged at 650 °C showed almost liner relation while this correlation was diminished for the specimens aged at 800 °C. The results may be attributed to the further formation of precipitates on specimens aged at temperature of 800 °C.

Research highlights
► Correlation between DOS and CPT on DSS2205 has been investigated.
► By increase in ageing time DOS increases and CPT decreases.
► Effect of ageing in 800 °C was higher on microstructural changes than 650 °C.
► DOS and CPT show liner relation in specimens aged at 650 °C.
► There was no relation between DOS and CPT in 800 °C aged specimens.