Analysis of circumferentially welded thin-walled cylinders to study the effects of tack weld orientations and joint root opening on residual stress fields

Abstract

In recent years, the demand for resilient welded structures with excellent in-service load-bearing capacity has been growing rapidly. The operating conditions (thermal and/or structural loads) are becoming more stringent, putting immense pressure on welding engineers to secure excellent quality welded structures. The local, non-uniform heating and subsequent cooling during the welding processes cause complex thermal stress-strain fields to develop, which finally leads to residual stresses, distortions, and their adverse consequences. Residual stresses are of prime concern to industries producing weld-integrated structures around the globe because of their obvious potential to cause dimensional instability in welded structures, and contribute to premature fracture/failure along with significant reduction in fatigue strength and in-service performance of welded structures. Arc welding with single or multiple weld runs is an appropriate and cost-effective joining method to produce high-strength structures in these industries. Multi-field interaction in arc welding makes it a complex manufacturing process. A number of geometric and process parameters contribute significant stress levels in arc-welded structures. In the present analysis, parametric studies have been conducted for the effects of a critical geometric parameter (i.e. tack weld) on the corresponding residual stress fields in circumferentially welded thin-walled cylinders. Tack weld offers considerable resistance to the shrinkage, and the orientation and size of tacks can altogether alter stress patterns within the weldments. Hence, a critical analysis for the effects of tack weld orientation is desirable.welding are unavoidable. Actually, intense localized heating (expansion) followed by rapid cooling (contraction) of the material in and around the weld region produces significant residual stress fields [1]. These high-magnitude residual stresses of the order of the yield strength of the material [2] within the heataffected zone (HAZ) can be a major threat for the in-service structural integrity of welded structures.The precise prediction of residual stress fields (magnitude and trends) is not an easy task due to the complexity involved, including short-term localized heating and rapid cooling, temperature-dependent material behaviour, moving heat source, and metallurgical transformations. Accordingly, finite-elementbased (FE-based) numerical simulations gained JMES1191

Bending fatigue behaviour and microstructure in welded high-strength bolt structures

“…Because materials of high-strength bolts are often difficult to weld, studies are required to focus on fatigue strength properties in the welded bolt structures, their characteristics, and mechanisms involved in the fracture process. 5–9…”

“…Bainitic steels can not only easily obtain high strength but also has notch toughness at low temperature, has suitable microstructure control rolling and forming workabilities and has high weldability as well. 2,5,8…”

Mechanical constraint effect on residual stress and distortion in T-fillet welds by three-dimensional finite element analysis

“…Due to the mechanical constraints imposed by the initial tack welding of the parts in the welding arrangement, the thermal gradient may produce residual stress and/or distortion in the joined metals. 1,2 The distortion and residual stress in welded components are undesirable and major efforts have been directed to control and reduce them. In T-fillet welds of beams and column joints in steel constructions, different types of mechanical constraint is achieved by the change in sequence of tack welding the parts.…”

“…Hence, there has been a need to study the effect of the initial mechanical constraints on structures to be welded to obtain an accurate estimation of the final deformation and residual stresses. 2,3 In steel-welded structures, the distortion is due to local shrinkage in the weld caused by rapid heating and cooling, and can be categorized by longitudinal, transverse, and angular forms. 4 These are inherent deformations and their extent can be influenced by the heat input intensity, design of joint geometry, plate thickness, and ultimately by the position and sequence of tack welding of the parts during the welding process.…”

“…4 These are inherent deformations and their extent can be influenced by the heat input intensity, design of joint geometry, plate thickness, and ultimately by the position and sequence of tack welding of the parts during the welding process. 1,2 Accurate simulation of welding process should be carried out by considering thermal, metallurgical, and mechanical aspects of the process. [5][6][7][8][9][10][11] In many researches particularly where the weld of low carbon steel has been studied, the modeling was achieved by only sequentially coupled thermal-mechanical analysis.…”