PSI - Issue 68

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

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 68 (2025) 822–827

European Conference on Fracture 2024 Development of a numerical model for estimating the hardness of steel after quenching Ema Kukuljan a , Robert Basan a, *, Dario Iljkić a , Ela Marković a a University of Rijeka, Faculty of Engineering, Vukovarska 58, HR-51000 Rijeka, Croatia Abstract For estimation of hardness of steel after quenching, the transient thermal numerical model was developed enabling simulation of the quenching process i.e., rapid cooling of the steel specimen in the quenching medium. Relevant variables in heat transfer during quenching process are geometry of the specimen, temperatures of quenchant and specimen and related material and heat transfer coefficients. Due to the unknown values of the heat transfer and heat conduction coefficients, numerical model and corresponding parameters were calibrated based on simulated cooling curves and reference cooling curves for both the surface and the core of the specimens obtained from the literature. During the development of the numerical model, particularly high influence of the heat transfer coefficient and to a somewhat lesser degree that of heat conduction coefficient and their significant dependence on temperature was observed. Iterative calibration procedure that considers the non-stationarity of these coefficients was performed. For model validation, the obtained hardness values were compared with experimental results from literature. © 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: numerical analysis, quenching, steel, hardness, estimation 1. Introduction Heat treatment processes modify the properties of materials such as steel through controlled heating and cooling. Quenching is widely used to enhance hardness and other mechanical properties of entire steel components or selected regions (e.g., the surface) to improve their performance in various industrial applications. a © 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

* Corresponding author. Tel.: +385-51-651-530; fax: +385-51-651-416. E-mail address: robert.basan@riteh.uniri.hr

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.2025.06.136