Microstructure characterization and mechanical properties of austenitic Super 304H steel after operation

• Published in: The International journal of pressure vessels and piping Vol. 211; p. 105294
• Main Authors: Purzyńska, H., Golański, G., Sroka, M., Sasiela, A., Zieliński, A.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-10-2024
• Subjects: Mechanical properties; Microstructure; Precipitation; Super 304H steel; Mechanical properties; Super 304H steel; Precipitation; Microstructure
• ISSN: 0308-0161
• DOI: 10.1016/j.ijpvp.2024.105294

The paper presents the results of testing the microstructure and mechanical properties of austenitic Super 304H steel after approximately 31,000 h of operation at a temperature of 570 °C. The microstructure analysis showed that the utilization of the tested steel contributed to the precipitation of numerous M23C6 carbides and individual sigma phase particles at grain boundaries, while dispersive ε_Cu and MX particles was observed inside the grains. At the grain boundaries, the precipitates sometimes formed a continuous mesh. The presence of numerous secondary phases resulted in higher than standard strength properties while maintaining the required plastic properties.
•Austenitic creep-resistant Super 304h steel after long-term service has been investigated.•Changes in the microstructure after long-term service have been examined.•Precipitation of the secondary carbides M23C6, sigma, MX and ε_Cu was observed after service.