Creep, fatigue and creep-fatigue behaviour of martensitic/bainitic steels and nickel-based alloys and their welded joints at the temperature range 500°C–750°C

ABSTRACT

The aim of the paper is to investigate experimentally the fatigue and creep-fatigue material behaviour of improved materials and welded joints for the application in flexible future power plants. These materials promise a reduction in manufacturing costs as well as an increase in flexibility by providing enhanced creep strength thorugh a wall thickness reduction. At the temperature range between 500°C −550°C, the investigation focusses on the creep and low-cycle fatigue behaviour of dissimilar welded joints from conventional materials (bainitic and martensitic materials T24 and T92) to nickel-based alloys (A617B and HR6W) fabricated as tubes. At the temperature range between 700°C and 750°C, it focusses on the creep, low-cycle fatigue and creep-fatigue behaviour of similar and dissimilar welded joints from nickel-based alloys (A740H, A617B and A263) fabricated as tubes and as pipes. Metallographic investigations after testing provide support for understanding the influence of temperature, strain amplitude and dwell time on the microstructure change and the fatigue strength.

KEYWORDS:

• Creep
• fatigue
• creep-fatigue
• martensitic/bainitic steels
• nickel-based-alloy
• weld joints
• tube
• pipe

Additional Notes to Authors

Do you wish your paper to be submitted to Materials at High Temperatures … … … … … … Yes/No

Those papers accepted for inclusion in the MHT Journal will only appear in the conference proceedings as an abstract with reference to the full paper in the relevant edition of the Journal.

An abstract book will be included within the delegate pack as below. You are invited to include a photo of the main author/presenter, to aid networking at the conference. If you prefer not to supply a photo we will happily include the abstract without a photo.

Any questions relating to paper/presentation and submission to paper please contact the Chair of the Scientific Committee Dr Augusto Di Gianfrancesco, [email protected].

Any questions relating to the organisation of the conference, registration or administration please contact the Chair of the Organising Committee Dr Peter Barnard, [email protected]

Acknowledgments

The results presented in this paper were generated within the European Research Project “Ni-based alloys for Operation of 725°C Power Plants, acronym NIBALO725“. This project has received funding from the Research Fund for Coal and Steel under grant agreement No. 709976. The authors thank the project consortium for the fruitful discussion during the project meetings, especially Special Metals for providing the A740H material (tube and pipe) and GE Power GmbH (former GE Boiler Deutschland GmbH) for the fabrication of the pipe and tube weldments.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Research Fund for Coal and Steel [709976].