This research work studies the microstructural changes in SAF 2507 superduplex stainless
steel after thermal cycle in the range from 200 to 900°C for 20 minutes. The results
showed there is no microstructural change in the temperature range of 200-700°C. However,
over 800°C the sigma phase precipitates; the percentage of this phase increases with
temperature. Sigma phase precipitates at the boundaries of δ/δ and δ/γ. The experimental
results also showed precipitation of small particles of sigma phase at 900°C all over
the microstructure showing the initial stages of formation.