Issue 47

P. Ferro et al., Frattura ed Integrità Strutturale, 47 (2019) 221-230; DOI: 10.3221/IGF-ESIS.47.17 221 Fracture and Structural integrity: ten years of ‘Frattura ed Integrità Strutturale’ Numerical modelling of residual stress redistribution induced by TIG-dressing P. Ferro, F. Bonollo University of Padova, Italy paolo.ferro@unipd.it , https://orcid.org/0000-0001-8682-3486 franco.bonollo@unipd.it, https://orcid.org/0000-0002-7196-2886 F. Berto University of Trondheim (NTNU), Norway filippo.berto@ntnu.no , https://orcid.org/0000-0002-4207-0109 A. Montanari University of Rome, Italy roberto.montanari@uniroma2.it , https://orcid.org/0000-0001-7791-4431 A BSTRACT . TIG-dressing is a technique used to improve the fatigue strength of welded joints by a remelting of the weld toe region that promotes both a smoother transition between the plate and the weld crown and a residual stress redistribution. These effects are very hard to be quantified by numerical simulation since a highly coupled thermo-fluid-mechanical analysis is required. However, if the final weld toe geometry is supposed to be known or a-posteriori measured, a simplified numerical method can be used to simulate the residual stress redistribution that uses the activation-deactivation function of elements. This technique is applied to a real steel weldment and the results, in terms of phases proportions and residual stress redistribution, were found in good agreement both with data coming from metallurgical analysis and the improved fatigue strength observed on welded joints after the TIG-dressing operation. K EYWORDS . Numerical modelling; Welding; TIG-dressing; Residual stress; Microstructure; Phase transformation Citation: Ferro, P., Berto, F., Bonollo, F., Montanari, R., Numerical modelling of residual stress redistribution induced by TIG- dressing, Frattura ed Integrità Strutturale, 47 (2019) 221-230. Received: 17.08.2018 Accepted: 21.09.2018 Published: 01.01.2019 Copyright: © 2019 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION everal studies have demonstrated that unwelded plain material shows a linear relation between static strength and fatigue strength, but that the presence of notches results in a reduction of the fatigue strength. As a result, the fatigue strength of different steel grades is usually assumed to be equal in design codes. The low fatigue strength of S