Effect of Rare Earth on Oxidation Behavior of 9Cr-3Co-2W Martensitic Heat-resistant Steel in 625 ℃ Water Vapor Environment
Steam oxidation corrosion resistance is an important index to evaluate boiler steel. In this study 9Cr-3Co-2W martensitic heat-resistant steel （/% 0.08C， 0.40Si， 0.40Mn， 9.00Cr， 0.20Ni， 0.50Mo， 1.50 W. 0.05Nb， 0.20V， 0.07N， 0.030Al， 0.0012B， S≤0.010， P≤0.020）， the oxidation kinetics curves of the tw...
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| Format: | Article |
| Language: | zho |
| Published: |
Editorial Office of Special Steel
2025-08-01
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| Series: | Teshugang |
| Subjects: | |
| Online Access: | https://www.specialsteeljournal.com/fileup/1003-8620/PDF/2025-00066.pdf |
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| Summary: | Steam oxidation corrosion resistance is an important index to evaluate boiler steel. In this study 9Cr-3Co-2W martensitic heat-resistant steel （/% 0.08C， 0.40Si， 0.40Mn， 9.00Cr， 0.20Ni， 0.50Mo， 1.50 W. 0.05Nb， 0.20V， 0.07N， 0.030Al， 0.0012B， S≤0.010， P≤0.020）， the oxidation kinetics curves of the two groups without rare earth and with rare earth w［Ce］ 0.03% in 625 ℃ water vapor environment were carried out， and the morphology and structure of the oxide film were analyzed by SEM and XRD. The results show that the outer layer of iron oxide scale in both sets of experimental steel are mainly rich in Fe oxide Fe3O4 or Fe2O3， and the inner layer is rich in Cr and Fe oxides （Fe，Cr）2O3 and （（Fe，Cr）3O4 in the 625 ℃ water vapor environment. However， the outer layer of iron oxide scale in the experimental steel without rare earth addition has poor density ， and even cracks appear. The experimental steel with rare earth added has dense outer oxide layer and large chromium-rich oxide layer thickness. On the surface of the oxidation kinetics curve， at the initial stage of oxidation （0 h-200 h）， with the extension of oxidation time， the oxidation rate of the test steel is large. After the oxidation time exceeds 200 h， the oxidation rate gradually decreases， and after 2 000 h， the oxidation rate approaches the level， and the oxidation rate continues to decline and gradually becomes stable. The addition of a small amount of rare earth Ce can help to form a dense oxide film and improve the oxidation resistance of the steel. |
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| ISSN: | 1003-8620 |