PSI - Issue 72

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ScienceDirect

Procedia Structural Integrity 72 (2025) 157–163

12th Annual Conference of Society for Structural Integrity and Life (DIVK12) Comparison of the Properties of the Welded Joint of Structural Steel S235 and S460 Before and After Incremental Sheet Forming Nedeljko Vukojević a, * , Zlatan Ištvanić b , Fuad Hadžikadunić a , Amna Bajtarević - Jeleč a a Fakultetska br.1, 72000 Zenica, Bosnia and Herzegovina, University of Zenica, Faculty of Mech. Eng. b Bage br.5, 70100 Jajce, Bosnia and Herzegovina, Metacomm Jajce Ltd. Abstract Pressure vessel heads are made by plastic deformation of steel sheets. One of the production processes is incremental sheet forming (ISF). This plastic deformation treatment causes changes in the base steel sheets, which can have positive or negative. The focus of the research is the heat affected zone in the welded joint. The application of the ISF process affects the mechanical properties differently, depending on the quality of the material, the thickness of the sheet, and diameter of sheet which is the subject of analysis in this paper. Experimental research was carried out on two diameters and two thicknesses of steel sheets and typical materials of grades S235JR+N and P460NL1.The research included standard destructive tests aimed at determining the actual mechanical properties of the welded joint (HAZ), measuring hardness, determining value of residual stresses on samples taken from the welded joint zone of the finally shaped vessel heads. © 2026 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 Aleksandar Sedmak, Branislav Djordjevic, Simon Sedmak Dr. Simon Sedmak, ssedmak@mas.bg.ac.rs, Innovation Center of Faculty of Mechanical Engineering, Belgrade, Serbia

Keywords: Heat Affected Zone; Incremental Sheet Forming; Pressure Vessel Heads; Steel S235 and S460

1. Introduction The mechanical tests presented in this paper aim to provide a more complete understanding of the condition of dish ends of pressure vessels made by welding. The procedure applied in this study was conducted to investigate and obtain adequate insights into the state and behavior of welded joints of plates for making dish ends through an incremental plastic deformation. The dish ends were produced using a progressive plastic deformation in process developed in

* Corresponding author - Phone: +387 61 175 998; Fax: +387 32 426 612. E-mail address: nedeljko.vukojevic@unze.ba

2452-3216 © 2026 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 Aleksandar Sedmak, Branislav Djordjevic, Simon Sedmak Dr. Simon Sedmak, ssedmak@mas.bg.ac.rs, Innovation Center of Faculty of Mechanical Engineering, Belgrade, Serbia 10.1016/j.prostr.2025.08.087