Abstract
The creep-fatigue properties of modified 9Cr-1Mo (grade 91) steel have been investigated for the purpose of design in cyclic service. In this paper test results from creep-fatigue (CF) and low cycle fatigue (LCF) on grade 91 steel are reported. The tests performed on the high precision pneumatic loading system (HIPS) are in the temperature range of 550-600ºC, total strain range of 0.7-0.9% and with hold periods in both tension and compression. Curves of cyclic softening and stress relaxation are presented. The CF test results and results obtained from literature are also analysed using methods described in the assessment and design codes of RCC-MRx, R5 and ASME NH as well as by the recently developed Φ-model. It is shown that the number of cycles to failure for CF data can be accurately predicted by the simple Φ-model. The practicality in using the life fraction rule for presenting the combined damage is discussed and recommendations for alternative approaches are made.
| Original language | English |
|---|---|
| Title of host publication | Advances in Materials Technology for Fossil Power Plants |
| Subtitle of host publication | Proceedings from the 7th International Conference, EPRI 2013 |
| Editors | D. Gandy, J. Shingledecker |
| Publisher | Electric Power Research Institute |
| Pages | 679 - 689 |
| ISBN (Print) | 978-1-6270-8060-6 |
| Publication status | Published - 2013 |
| MoE publication type | Not Eligible |
| Event | 7th International Conference on Advances in Materials Technology for Fossil Power Plants - Waikoloa, United States Duration: 22 Oct 2013 → 25 Oct 2013 Conference number: 7 |
Conference
| Conference | 7th International Conference on Advances in Materials Technology for Fossil Power Plants |
|---|---|
| Country/Territory | United States |
| City | Waikoloa |
| Period | 22/10/13 → 25/10/13 |
Keywords
- grade 91 steel
- creep-fatigue
- life fraction rule
- modelling