PSI - Issue 68

Ema Kukuljan et al. / Procedia Structural Integrity 68 (2025) 822–827 E. Kukuljan et al. / Structural Integrity Procedia 00 (2025) 000–000

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3. Approach to the estimation of hardness after quenching The approach to the estimation of hardness distribution in quenched steel specimen is based on cooling curves from which values of t 8/5 representing the times required for cooling from 800°C to 500°C are determined, and used for the analytical determination of resulting hardness using Jominy results and related values. Based on the obtained t 8/5 cooling times, the Jominy distance is determined from the diagram describing the relationship between t 8/5 and Jominy distance for all steels. After that, the hardness corresponding to this Jominy distance is identified using the diagram that describes the relationship between the Jominy distance and the achieved hardness (Fig. 2.).

Fig. 2. Determination of hardness based on value of t 8/5 , Smoljan et al. (2015).

Cooling curves from which times t 8/5 are obtained can be determined experimentally but since this task is complex and demanding, the aim of this work is the development of a numerical model enabling simulation of the quenching process and obtaining cooling curves and t 8/5 times numerically. 4. Numerical model For the required simulation of the quenching process as described in section 2, transient thermal numerical analysis in ANSYS was selected, Ansys Inc. (2010). Due to the geometry and type of the problem, a cylindrical specimen is modeled as axisymmetric thus reducing the complexity of the simulation and calculation times (Fig. 3.).

Fig. 3. Cylindrical specimen modelled as axisymmetric plane finite element model