PSI - Issue 13

Hugo Wärner et al. / Procedia Structural Integrity 13 (2018) 843–848

848

Hugo Wärner et al./ Structural Integrity Procedia 00 (2018) 000 – 000

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Fig. 7. Crack initiation and propagation; (a) Overview of crack in TMF t d =0 s , ε a =0.4 %, ΔT=100 -800 °C virgin material; (b) EBSD-mapping for zoomed in region in (a); (c) Overview of small crack in CF t d =300 s, ε a =0.25 %; (d) EBSD-mapping for region in (c). (Horizontal loading direction)

3. Conclusions The low cycle fatigue (LCF), thermo-mechanical fatigue (TMF) and creep-fatigue interaction (CF) behavior of Sanicro 25 have been analyzed. From the discussed results, these conclusions are deduced:  For all testing conditions, Sanicro 25 shows cyclic hardening and this effect is further promoted by increased strain ranges, decreased dwell times, decreased temperature ranges and pre-aging.  Coffin-Manson fatigue life curves for TMF and CF are shifted to the lower fatigue lives compared to LCF.  The influence of aging is different between TMF and CF, where the aging reduces the cyclic life for TMF conditions in contrast to CF condition where aging increases the cyclic life.  For LCF, TMF and CF crack initiation appear in multiple grain boundaries at the surface of the specimen. The crack initiation in the three different testing conditions are oxidation assisted. Acknowledgements Present study was financially supported by AB Sandvik Materials Technology in Sweden and the Swedish Energy Agency through the Research Consortium of Materials Technology for Thermal Energy Processes, Grant No. KME-701. AFM Strategic Faculty Grant SFO-MAT-LiU#2009-00971 at Linköping University is also acknowledged. The support by IPMinfra through projects No. LM2015069 and CEITEC 2020 No. LQ1601 of MEYS, Czech Rep. is also acknowledged. References Blum R., Vanstone R W., and Messelier-Gouze C., 2004. Materials Development for Boilers and Steam Turbines Operating at 700°C. In Proceedings of 4th International Conference on Advancement in Material Technology for Fossil Power Plant, South Carolina, pp. 116. Chai G., Nilsson J O., Boström M., Högberg J., and Forsberg U., 2010. Advanced heat resistant austenitic stainless steel. In Proceedings of the ICAS 2011, Guilin City, China, pp. 56. Chai G., BoströmM., Olaison M., and Forsberg U., 2013. Creep and LCF Behaviors of Newly Developed Advanced Heat Resistant Austenitic Stainless Steel for A-USC. In Procedia Engineering 55, pp. 232. Gibbons T B., 2013. Recent advances in steels for coal fired power plant: A review. In Transactions of the Indian Institute of Metals 66, pp. 631-640. Heczko M., Esser B.D., Smith T.M., Beran P., Manzánová V., McComb D.W., Kruml T., Polák J., Mills M.J., 2018. Atomic resolution characterization of strengthening nanoparticles in a new high-temperature-capable 43Fe-25Ni-22.5Cr austenitic stainless steel. Materials Science and Engineering A 719, pp. 49-60. Petrá š R., Škorík V., Polák J, 2016. Thermomechanical fatigue and damage mechanisms in Sanicro 25 steel. Materials Science and Engineering A 650, pp. 52-62. Polák J., Petrá š R., Heczko M., Kuběna I., Kruml T., Chai G., 2014. Low cycle fatigue behavior of Sanicro25 steel at room and at elevated temperature. In Materials Science and Engineering A 615, pp. 175-182. Rautio R., Bruce S., 2004. A new material for ultrasupercritical coal fired boiler. In Proceedings of 4th International Conference on Advancement in Material Technology for Fossil Power Plant, Hilton Head Island, South Carolina, pp. 274. Sandvik AB. 2017. Sanicro 25 Tube and Pipe, Seamless Datasheet. https://www.materials.sandvik/en/materials-center/material-datasheets/tube-and pipe-seamless/sanicro-25/?show=pdf. Viswanathana R., Colemana K., and Rao U., 2006. Materials for ultra-supercritical coal-fired power plant boilers. International Journal of Pressure Vessels and Piping 83, pp. 778. Wärner H., Calmunger M., Chai G., Moverare J., 2018. Creep-fatigue interaction in heat resistant austenitic alloys. Fatigue 2018 MATEC Web of Conferences 165:05001. Wärner H., Calmunger M., Chai G., Johansson S., Moverare J. 2017. Thermomechanical Fatigue Behavior of Aged Heat Resistant Austenitic Alloys. EUROMAT17, Thessaloniki, Greece, urn:nbn:se:liu:diva-143978 (URN).