PSI - Issue 68

D. Tomerlin et al. / Procedia Structural Integrity 68 (2025) 1237–1244 D. Tomerlin et al./ Structural Integrity Procedia 00 (2025) 000–000

1243

7

Fig. 7. da/dN -Δ K fatigue crack growth curve (Spec. 1.4)

4. Discussions and conclusions The fracture toughness testing showed that increasing the reheat temperatures in the 2 nd cycle decrease the fracture toughness properties J IC and K JIC . The 1 st cycle heating leads to the highest fracture toughness J IC and K JIC , and δ IC values, while 2 nd cycle reheating has nagative influence to material fracture toughness. In terms of fatigue crack growth, the IC CGHAZ structure exhibits the highest da/dN crack growth rate, while CGHAZ structure exhibits the least da/dN crack growth rate, along with brittle fracture. References aldur® High-strength quenched and tempered fine-grained steels, Voestalpine Grobblech, Linz, Austria, 2022. ASTM E399-22 – Standard Test Method for Linear-Elastic Plane-Strain Fracture Toughness of M.M. ASTM Int.: West C., PA, USA, 2022. ASTM E647-13 – Standard Test Method for Measurement of Fatigue Crack Growth Rates. ASTM Int.: West Conshohocken, PA, USA, 2014. ASTM E1820-15 – Standard Test Method for Measurement of Fracture Toughness. ASTM International: West Conshohocken, PA, USA, 2016. Bertolo, V., Jiang, Q., Terol Sanchez, M., Riemslag, T., Walters, C.L., Sietsma, J., Popovich, V., 2023. Cleavage fracture micromechanisms in simulated heat affected zones of S690 high strength steels. Materials Science and Engineering: A, Volume 868, 144762, https://doi.org/10.1016/j.msea.2023.144762. EN 1011-2:2001 – Welding – Recommendations for welding of metallic materials – Part 2: Arc welding of ferritic steels. CEN, Brussels, Belgium, 2001. EN 10025-6:2004 – Hot rolled products of structural steel – Part 6: Technical delivery conditions for flat products of high yield strength structural steels in the quenched and tempered condition. CEN, Brussels, Belgium, 2004. Gáspár M., 2019. Effect of Welding Heat Input on Simulated HAZ Areas in S960QL High Strength Steel. Metals, 9(11):1226. https://doi.org/10.3390/met9111226. Guillal, A., Abdelbaki, N., Gaceb, M., Bettayeb, M. 2018. Effects of martensite-austenite constituents on mechanical properties of heat affected zone in high strength pipeline steels-review, Chemical Engineering Transactions 70, 583-588. doi: 10.3303/CET1870098. Hochhauser, F., Ernst, W., Rauch, R., Vallant, R., Enzinger, N., 2012. Influence of the soft zone on the strength of welded modern hsla steels. Weld. World 56, 77–85. Kim, J.J., Pham, T-H., Kim, S-E., 2015. Instrumented indentation testing and FE analysis for investigation of mechanical properties in structural steel weld zone. International Journal of Mechanical Sciences 103, 265-274. https://doi.org/10.1016/j.ijmecsci.2015.09.015.