Creep deformation and rupture behaviour of service-exposed Super304H steel boiler tubes

ABSTRACT

The determination of creep properties of the components operating at high temperatures in thermal power plants is an enormous concern for safe life assessment. In this study, a series of miniature creep and tension tests were carried out with service-exposed (54,750 h and 68,550 h at 650 °C) and virgin Super304H steel materials. The power law creep behaviour, creep rupture life, and tensile properties were compared among the virgin and service-exposed materials. The creep strength of the 54,750-h-serviced material was comparable to that of the virgin material, while it decreased significantly for the 68,550-h-serviced material. The degradation of the properties of the service-exposed material was discussed based on metallurgical analyses and precipitation mechanisms.

KEYWORDS:

• Super304H
• ageing
• creep
• boiler Tube
• M₂₃C₆
• niobium

Acknowledgments

This work was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) with a grant (No. 2016 1110100090) funded by the Ministry of Trade, Industry, and Energy (MOTIE). This study was also supported with another KETEP grant (No. 2014 1010101850) funded by the MOTIE. Authors appreciate Mr. Lok Vanno’s technical support.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Korea Institute of Energy Technology Evaluation and Planning [20141010101850]; Korea Institute of Energy Technology Evaluation and Planning [20161110100090].