Original scientific paper

https://doi.org/10.17559/TV-20250414002592

Experimental and Numerical Evaluation of Residual Stresses Caused by Welding the Nozzle to the Header

Darko Damjanovic orcid.org/0000-0002-7341-6029 ; University of Slavonski Brod, MEF, Trg Ivane Brlic Mazuranic 2, 35 000 Slavonski Brod, Croatia *
Marko Pavkovic ; Koncar - Metalnekonstrukcije d.o.o., Fallerovosetaliste 22, 10 000 Zagreb, Croatia
Rehan Khan ; National University of Sciences and Technology, Islamabad 44000, Pakistan
Lorenzo Scappatiacci ; 5Allimep SRL, Via dell' Acciaio 7, 06134 Perugia, Italy

* Corresponding author.

Abstract

Residual stresses play a critical role in determining the structural integrity and performance of engineering components and systems. This paper presents a comprehensive investigation into the numerical and experimental assessment of residual stresses caused by welding nozzles to the header. The diameter and wall thickness of the nozzle as well as the diameter of the header are the same in all considered cases, while the wall thickness of the header wall is varied. Three specimens were investigated. The research aims to provide a deeper understanding of the influence of header wall thickness to the residual stresses caused by welding. The Finite Element Method was used to model the heat input during welding and evaluate the residual stresses and deformations. The main focus is on the residual stresses. The numerical models are validated against experimental measurements using semi-destructive measurement method: Incremental Hole Drilling Method according to ASTM E837. The data obtained from experiments are compared with the numerical simulations, leading to a comprehensive assessment of the model's accuracy and predictive capabilities. A very good correlation between both, experimental and numerical approach was obtained. In particular, the study demonstrates that increasing the wall thickness of the header leads to higher residual stresses near the weld, which is crucial information for design engineers aiming to balance mechanical strength with stress control. The validated numerical approach also provides a reliable tool for early-stage design optimization, enabling engineers to simulate and refine welding strategies before actual fabrication. The combination of experimental and numerical approaches provides a holistic view of residual stress evaluation and its applications across various industries, specific in this paper, in the boiler industry, where the equipment operates under pressure and elevated temperatures and weld residual stresses should not be neglected as usual.

Keywords

ASTM E837; header; nozzle; residual stress; welding

Hrčak ID:

335073

URI

https://hrcak.srce.hr/335073

Publication date:

30.8.2025.

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