Journal of Welding Science

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Fusion welding is widely used in heavy industries to join different parts together. But sometimes welding-induced distortions cause problems like misalignment during assembling and make costs to remove them. Thus it is imperative to predict and mitigate them to improve weldments quality and also reduce in fabrication costs. This study at first will introduce inherent deformation method for prediction of welding-induced distortion. In following a relatively large panel will be simulated by finite element software ANSYS and its distortion will be calculated. The results will be compared by experimental measurement. Afterward this investigation will present an efficient welding sequence which produce minimal distortion.

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In this research in order to improve the mechanical properties of Aluminium alloy 2024, nanostructure Aluminum sheets were first produced by Cryorolling process and then was welded by resistance spot welding method. For this purpose, the samples solution treated at 495˚C for 55 minute and subsequently cryorolled up to 85% reduction in thickness. For obtaining simultaneous strength and ductility, the cryorolled sheets were then subjected to aged. In this regard the produced samples were then resistance spot welded with different welding parameters, including welding current 60 to 105 KA, electrode force of 3 KN, and welding time of 0.1 s. The highest tensile shear peak load was obtained through welding with 95 KA current.

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Friction stir spot welding (FSSW) is a type of solid state welding that is used in the connection of small pieces and light metals such as aluminum alloy especially. The technical problem during melting of aluminum alloys is one of the most important reasons for developing application of friction stir welding for aluminum alloys. In this research, the effects of important processing parameters such as tool rotation speed, dwell time, plunge depth of tool and sheets thickness on the mechanical properties such as failure force and energy of FSS welded AA-3105 alloy have been experimentally studied using micro hardness and tensile tests. Tensile-shear tests show four different fracture modes of weld failure which consist of shear fracture, circumferential fracture, nugget pull out fracture and fracture in base material modes. The results show that the weld strength drops with increasing the tool rotation speed. Strength and hardness of weld and weld zone increase and then decrease with increasing dwell time of rotational tool which it can be obtained an optimum value of dwell time. Strength and fracture energy and load of welds increases with increasing the sheet thickness

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Today in addition to Join by friction stir welding, the composite fabrication process is also performed simultaneously. The main purpose of the present research is to investigate the effect of pin geometry on the property of Aluminum 6061- alumina nanocomposite created by friction stir welding. For this purpose friction stir welding was carried out by selecting five types of pin geometries on Aluminum 6061 in which Al2O3 particles were deposited and the samples were examined by tensile and hardness tests, optical and electron microscope. Samples were investigated by tensile and hardness test, optical and electronic microscopy. Regular hexagonal pins due to having six smooth face and impulsive movement during rotation, caused a good perturbation which resulted in maximum tensile strength and elongation percentage of 198 MPa and 10.25 and minimum grain size of 13.3 micron, respectively. In the sample welded by a threaded cylindrical pin due to non-impact during rotation, inappropriate flow of reinforcing particles and its accumulation at perturbation the lowest tensile strength and elongation percentage of 133.5 MPa and 1.95%, respectively, were observed.