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.
SAF 2507 superduplex stainless steel; sigma phase; thermal cycle
