Influence of thermo-mechanical material properties on the structural response of a welded butt-joint by FEM simulation and experimental tests

Effect of Metal-Cored Filler Wire on Surface Morphology and Micro-Hardness of Regulated Metal Deposition Welded ASTM A387-Gr.11-Cl.2 Steel Plates

Environmental and human-friendly welding is the need of the hour. In this context, this study explores the application of the regulated metal deposition (RMD) technique for ASTM A387-Gr.11-Cl.2 steel plates. To examine the effect of metal-cored filler wire (MCFW), MEGAFIL 237 M was employed during regulated metal deposition (RMD) welding of 6 mm thick ASTM A387-Gr.11-Cl.2 steel plates. The welding was carried out at an optimized current (A) of 100 A, voltage (V) of 13 V, and gas flow rate (GFR) of 21 L/min. Thereafter, the as-welded plates were examined for morphological changes using optical microscopy. Additionally, the micro-hardness of the as-welded plates was measured to make corroboration with the obtained surface morphologies. In addition to this, the as-welded plates were subjected to heat treatment followed by surface morphology and micro-hardness examination. A comparison was made between the as-welded and heat-treated plates for their obtained surface morphologies and microhardness values. During this, it was observed that the weld zone of as-welded plates has a dendritic surface morphology which is very common in fusion-based welding. Similarly, the weld zone of heat-treated plates has a finer and erratic arrangement of martensite. Moreover, the obtained surface morphologies in the weld zone of as-welded and heat-treated plates have been justified by their respective hardness values of 1588.6 HV and 227.3 HV.

Numerical Simulation and Experimental Measurement of Residual Stresses in a Thick-Walled Buried-Arc Welded Pipe Structure

In this study, a numerical simulation of a single pass welding of two thick-walled pipes with the buried-arc method was performed in order to determine the residual stresses caused by welding. The numerical simulation procedure in the thermal analysis was performed by the element birth and death method while the structural analysis was performed simultaneously, without the application of the element birth and death technique in order to reduce the duration of the numerical simulation. The simulation results were validated by experimental residual stress measurements on the outside surfaces of the welded model using the X-ray diffraction technique. A good agreement between the results of the numerical simulation and experimental measurements was confirmed.

FEM Simulation and Experimental Tests on the SMAW Welding of a Dissimilar T-Joint

Residual stresses induced by the welding processes may, in some cases, result in significant warping and distortions that can endanger the integrity of the welded structures. This document reports an investigation of the welding process to make a dissimilar T-joint through an advanced Finite Element (FE) modelling and a dedicated laboratory test. The T-joint consisted of two plates of dissimilar materials, AISI304 and S275JR steels, both having a thickness of 5 mm, welded through a Shielded Metal Arc Welding (SMAW). Thermocouples were used to acquire the temperature variations during welding. In parallel, an FE model was built and the welding process was simulated through the “element birth and death” technique. Numerical and experimental outcomes were compared in terms of temperature distributions during welding and in terms of distortion at the end of the final cooling, showing that the FE model was able to provide a high level of accuracy.