**Analysis of Longitudinal Residual DeflectionsinT-jointWeldedStructure**

#### **MatoPeri´c 1,IvicaGaraši´c 2,Sandro Nižeti´c 3,\*andHrvojeDedi´c-Jandrek 3**

**Preheating**

1 Bestprojekt, Bureau of Energetics and Mechanical Engineering Ltd., Petrovaradinska 7, 10000 Zagreb, Croatia; mato.peric@fsb.hr

2 Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, I. Luˇci´ca 5, 10000 Zagreb, Croatia; ivica.garasic@fsb.hr

 **a** 

**Technique**


Received: 16 November 2018; Accepted: 11 December 2018; Published: 14 December 2018

**Abstract:** In this paper a numerical analysis of a T-joint fillet weld is performed to investigate the influences of different preheat temperatures and the interpass time on the longitudinal residual stress fields and structure deflections. In the frame of the numerical investigations, two thermo-mechanical finite element models, denoted M2 and M3, were analyzed and the results obtained were then compared with the model M1, where the preheating technique was not applied. It is concluded that by applying the preheat temperature prior to the start of welding the post-welding deformations of welded structures can be significantly reduced. The increase of the preheat temperature increased the longitudinal residual stress field at the ends of the plates. The influence of the interpass time between two weld passes on the longitudinal residual stress state and plate deflection was investigated on two preheated numerical models, M4 and M5, with an interpass time of 60 s and 120 s, respectively. The results obtained were then compared with the preheated model M3, where there was no time gap between the two weld passes. It can be concluded that with the increase of interpass time, the plate deflections significantly increase, while the influence of the interpass time on the longitudinal residual stress field can be neglected.

**Keywords:** welding residual stress; welding deflection; T-joint fillet weld; preheat temperature; interpass time; finite element analysis
