| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1616954 | Journal of Alloys and Compounds | 2011 | 10 Pages |
In 25% Cr duplex stainless steels, the effect of prior-solution treatment temperature (STT) on the microstructure and corrosion behavior with ageing at 750 °C and 850 °C was investigated. The results revealed that the precipitation rate of σ-phase was fast in the early stage of ageing for 80 min, and then got slower with ageing time up to 330 min. The σ-phase formation was effectively suppressed by raising STT from 1060 °C to 1230 °C especially for ageing at 750 °C. Consequently, the corrosion rate of specimen was dependent on the amount of σ-phase precipitation, and was lowered due to higher STT, and more σ-phase precipitation can lead to the transition from metastable to stable pitting with ageing at 750 °C up to 330 min. Pitting occurred easily around coarse σ precipitates and caused selective dissolution in ferrite. The longer ageing time increased intergranular corrosion (IGC) susceptibility, whereas higher STT contributed to better resistance to IGC.
• The σ-phase precipitation was suppressed due to higher solution temperature. • Corrosion rate was dependent on the amount of σ-phase precipitation in initial ageing. • More σ-phase precipitation led to the transition from metastable to stable pitting. • Higher solution treatment temperature led to the formation of smaller pits. • Higher solution temperature contributed to the increase in resistance to IGC.
