PSI - Issue 68

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2025) 000–000

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ScienceDirect

Procedia Structural Integrity 68 (2025) 769–775

European Conference on Fracture 2024 Evaluation of surface and volume damages under HCF and VHCF loading for quenched and tempered steels S. R. Raghuraman a *, A. Shrivastava b , F. Weber a,c , A. Gramlich b , U. Krupp b , P. Starke a,c a University of Applied Sciences Kaiserslautern, Department of Materials Science and Materials Testing (WWHK), Institute QM 3 , Schoenstraße 11, 67657 Kaiserslautern, Germany Abstract Achieving climate neutrality requires new advancements and adaptions in various engineering sectors, especially in the field of the steel industry. While recycling steels is a promising approach to reduce CO 2 emissions and production costs, the quality of recycled steels may deteriorate over time because of impurity enrichment. Apart from that, most steel components are prematurely recycled before the end of their structural integrity is reached. Re-use, before recycling, provides an attractive approach, particularly for the quenched and tempered SAE 4140 steel considered within this research, as recycling in electric arc furnaces consumes substantial energy. Considering the High-Cycle-Fatigue loading, fatigue damage develops predominantly at surface irregularities, whereas damage in the Very-High-Cycle-Fatigue regime is mainly shifted into the volume of the material. To evaluate the re-use potential, specimens were primarily loaded at defined stress amplitudes in the High-Cycle-Fatigue regime. In order to determine appropriate load levels, the lifetime prediction method StressLife was used. It enables the generation of a trend S-N curve with only three fatigue tests and is based on different empirical relations and a combination of non-destructive testing methods with conventional destructive fatigue testing . These methods provide information regarding the material response during fatigue experiments. In addition to that, the extent of fatigue damage induced is determined analytically in terms of optical- and scanning electron microscopy. The primarily loaded specimens were reconditioned to remove surface damages and then subjected to secondary loading with stress amplitudes lower than the primary loading amplitudes. Based on these insights the re-use potential can be estimated. © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ECF24 organizers Keywords: High-Cycle-Fatigue (HCF); Very-High-Cycle-Fatigue (VHCF); primary loading; secondary loading, re-use potential © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ECF24 organizers b RWTH Aachen University, The Steel Institute (IEHK), Intzestraße 1, 52072 Aachen, Germany c Saarland University, Faculty of Natural Sciences and Technology, 66123 Saarbrücken, Germany

* Corresponding author. E-mail address: srinivasa.raghuraman@hs-kl.de

2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ECF24 organizers

2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of ECF24 organizers 10.1016/j.prostr.2025.06.128