Corrosion resistance of duplex stainless steel subjected to long-term annealing in the spinodal decomposition temperature range

The effect of thermal annealing up to 15,000 h between 300 °C and 500 °C on the corrosion resistance of the duplex stainless steel (DSS) 7MoPLUS has been investigated by using the DLEPR test. Spinodal decomposition in 7MoPLUS is unabated even after annealing for 15,000 h and no healing has been observed. The possible healing mechanisms in this temperature range (back diffusion of Cr atoms from the Cr-rich ferrite (αCr) and diffusion of Cr atoms from the austenite) and its absence in the present steel have been discussed.

► Long-term DLEPR data on duplex stainless steel.
► Spinodal decomposition remains unabated even after 15,000 h of annealing.
► Effect of long-term annealing on healing has been investigated.