Numerical Investigation of Transient Temperature and Residual Stresses in Thin Dissimilar Aluminium Alloy Plates

AbstractThe purpose of the present investigation is to assess transient temperature and residual stresses in Gas Metal Arc Welding (GMAW) of dissimilar aluminium alloys (AA). A moving heat source model based on Goldak's double – ellipsoid heat flux distribution is utilised in finite element simulation of welding process. To solve the three dimensional thermal and mechanical equations, ANSYS Workbench software was used. Element death and birth code was written for modelling the amount of material added during the analysis. Effects of conduction, convection and radiation were considered in transient thermal analysis. Temperature dependent properties as thermal conductivity, heat capacity, yield stress, elastic modulus and thermal expansion were employed in the welding simulations. Based on the results, it was found that lower temperature and higher residual stresses were generated in AA 6061-T6 plate as compared to AA 5052-H32 plate

Optimization of different welding processes using statistical and numerical approaches – A reference guide

Welding input parameters play a very significant role in determining the quality of a weld joint. The joint quality can be defined in terms of properties such as weld-bead geometry, mechanical properties, and distortion. Generally, all welding processes are used with the aim of obtaining a welded joint with the desired weld-bead parameters, excellent mechanical properties with minimum distortion. Nowadays, application of design of experiment (DoE), evolutionary algorithms and computational network are widely used to develop a mathematical relationship between the welding process input parameters and the output variables of the weld joint in order to determine the welding input parameters that lead to the desired weld quality. A comprehensive literature review of the application of these methods in the area of welding has been introduced herein. This review was classified according to the output features of the weld, i.e. bead geometry and mechanical properties of the welds

Experimental and numerical study to minimize the residual stresses in welding of 6082-T6 aluminum alloy

One of the most important negative consequence in the fusion welding processes is the generation of tensile residual stresses in welded joints. The main goals of this work are to determine the optimal combination of welding parameters to minimize the residual stress level and the influence of each welding parameter in that feature to weld 6082-T6 aluminum alloy plates using the GMAW welding process. To achieve these goals was implemented the Taguchi orthogonal array (L27) to define the design of numerical and experimental tests. All combinations were simulated in the Simufactwelding 6.0 software, from which it was possible to obtain the values of maximum residual stresses. The data treatment was carried out, reaching the combination of levels for each parameter. With ANOVA analysis was found that the parameter with the greatest influence in the residual stress generation was the welding speed, while the parameter with the least influence was the torch angle. Also, to minimize the residual stresses it was observed that the optimal combination of welding parameters is welding current intensity of 202 A, welding speed of 10 mm/s, and 30° of inclination of the angular torch. The two simulations that resulted in the highest and lowest residual stresses were validated experimentally by the hole drilling method to measure the residual stresses.info:eu-repo/semantics/publishedVersio

Engineering Principles

Over the last decade, there has been substantial development of welding technologies for joining advanced alloys and composites demanded by the evolving global manufacturing sector. The evolution of these welding technologies has been substantial and finds numerous applications in engineering industries. It is driven by our desire to reverse the impact of climate change and fuel consumption in several vital sectors. This book reviews the most recent developments in welding. It is organized into three sections: “Principles of Welding and Joining Technology,” “Microstructural Evolution and Residual Stress,” and “Applications of Welding and Joining.” Chapters address such topics as stresses in welding, tribology, thin-film metallurgical manufacturing processes, and mechanical manufacturing processes, as well as recent advances in welding and novel applications of these technologies for joining different materials such as titanium, aluminum, and magnesium alloys, ceramics, and plastics

Wire Arc Additive Manufacturing of Stainless Steels: A Review

Wire arc additive manufacturing (WAAM) has been considered as a promising technology for the production of large metallic structures with high deposition rates and low cost. Stainless steels are widely applied due to good mechanical properties and excellent corrosion resistance. This paper reviews the current status of stainless steel WAAM, covering the microstructure, mechanical properties, and defects related to different stainless steels and process parameters. Residual stress and distortion of the WAAM manufactured components are discussed. Specific WAAM techniques, material compositions, process parameters, shielding gas composition, post heat treatments, microstructure, and defects can significantly influence the mechanical properties of WAAM stainless steels. To achieve high quality WAAM stainless steel parts, there is still a strong need to further study the underlying physical metallurgy mechanisms of the WAAM process and post heat treatments to optimize the WAAM and heat treatment parameters and thus control the microstructure. WAAM samples often show considerable anisotropy both in microstructure and mechanical properties. The new in-situ rolling + WAAM process is very effective in reducing the anisotropy, which also can reduce the residual stress and distortion. For future industrial applications, fatigue properties, and corrosion behaviors of WAAMed stainless steels need to be deeply studied in the future. Additionally, further efforts should be made to improve the WAAM process to achieve faster deposition rates and better-quality control.</jats:p

A Comprehensive 3-D Model on Gas Metal Arc Welding

A unified comprehensive model was developed to simulate the transport phenomena occurring during the gas metal arc welding process. An interactive coupling between arc plasma; melting of a continuously fed electrode; droplet formation, detachment, transfer, and impingement onto the workpiece under the influences of several competing forces including gravity, electromagnetic force, arc pressure, plasma shear stress, and surface tension; and weld pool dynamics all were considered. The transient distributions of current density, arc temperature, arc pressure, melt flow velocity and melt temperature in the droplet and in the weld pool were all calculated. Based on the unified model, the following investigations were conducted: 1) the effect of welding current on droplet generation, especially the use of pulsed current to achieve the one-droplet-per-pulse (ODPP) metal transfer; 2) the determination of dynamically stabled wire feed speeds for given welding conditions; 3) the effects of surface active elements (Marangoni effect) on the weld pool flow and solidified weld profile; 4) the fundamental mechanisms leading to the formation of ripples; 5) the issues associated with the beginning and the end of the welding (limited penetration and the formations of crater); 6) the deflection of arc plasma by an external magnetic field

Design for Low-Cost Gas Metal Arc Weld-Based Aluminum 3-D Printing

Additive manufacturing, commonly known as 3-D printing, has the potential to change the state of manufacturing across the globe. Parts are made, or printed, layer by layer using only the materials required to form the part, resulting in much less waste than traditional manufacturing methods. Additive manufacturing has been implemented in a wide variety of industries including aerospace, medical, consumer products, and fashion, using metals, ceramics, polymers, composites, and even organic tissues. However, traditional 3-D printing technologies, particularly those used to print metals, can be prohibitively expensive for small enterprises and the average consumer. A low-cost open-source metal 3-D printer has been developed based upon gas metal arc weld (GMAW) technology. Using this technology, substrate release mechanisms have been developed, allowing the user to remove a printed metal part from a metal substrate by hand. The mechanical and microstructural properties of commercially available weld alloys were characterized and used to guide alloy development in 4000 series aluminum-silicon alloys. Wedge casting experiments were performed to screen magnesium, strontium, and titanium boride alloying additions in hypoeutectic aluminum-silicon alloys for their properties and the ease with which they could be printed. Finally, the top performing alloys, which were approximately 11.6% Si modified with strontium and titanium boride were cast, extruded, and drawn into wire. These wires were printed and the mechanical and microstructural properties were compared with those of commercially available alloys. This work resulted in an easier-to-print aluminum-silicon-strontium alloy that exhibited lower porosity, equivalent yield and tensile strengths, yet nearly twice the ductility compared to commercial alloys