Topic
Gas metal arc welding
About: Gas metal arc welding is a research topic. Over the lifetime, 11706 publications have been published within this topic receiving 109555 citations. The topic is also known as: metal active gas welding & GMAW.
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TL;DR: In this paper, the effects of three welding processes on the tensile, fatigue and corrosion behaviour were studied using optical and electron microscopes, and the results showed that the FSW joints exhibit superior tensile and fatigue properties compared to EBW and GTAW joints.
76 citations
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01 Jun 1994-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this paper, a model of the gas metal-arc (GMA) welding process in three dimensions for moving heat sources has been attempted using the finite element method, and the occurrence of finger penetration in the weldment resulting from a streaming type of metal transfer at high contents is explained by assuming that the heat content of transferring droplets is distributed in a certain volume of the workpiece below the arc.
Abstract: The modeling of the gas metal-arc (GMA) welding process in three dimensions for moving heat sources has been attempted using the finite element method. The occurrence of finger penetration in the weldment resulting from a streaming type of metal transfer at high contents is explained by assuming that the heat content of transferring droplets is distributed in a certain volume of the workpiece below the arc. Volumetric distribution of the heat content of transferring droplets has been considered as an internal heat-generation term, and the differences between penetration characteristics in two cases of globular and streaming conditions of metal transfer have been analyzed. It is shown that weld penetration depends on the depth at which the droplets distribute their energy inside the workpieces. Temperature dependence of thermophysical properties,i.e., thermal conductivity and specific heat, has been included. Latent heat is incorporated by a direct iteration method. Heat losses from the plate caused by convection and radiation are also considered. The model is validated by predicting the weld-bead dimensions and comparing them with experimental data.
76 citations
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TL;DR: In this article, a passive vision-sensing system, comprising two cameras and composite filtering techniques, was proposed for real-time detection of the bead height and width through deposition of thin walls.
Abstract: Additive manufacturing based on gas metal arc welding is an advanced technique for depositing fully dense components with low cost. Despite this fact, techniques to achieve accurate control and automation of the process have not yet been perfectly developed. The online measurement of the deposited bead geometry is a key problem for reliable control. In this work a passive vision-sensing system, comprising two cameras and composite filtering techniques, was proposed for real-time detection of the bead height and width through deposition of thin walls. The nozzle to the top surface distance was monitored for eliminating accumulated height errors during the multi-layer deposition process. Various image processing algorithms were applied and discussed for extracting feature parameters. A calibration procedure was presented for the monitoring system. Validation experiments confirmed the effectiveness of the online measurement system for bead geometry in layered additive manufacturing.
76 citations
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TL;DR: In this paper, a dynamic two-dimensional arc model was used to investigate the effects of various forces acting on the droplet in gas metal arc welding (GMAW), based on the equations of conservation of mass, energy, momentum and current, Ohm's law and a Maxwell equation.
Abstract: A dynamic two-dimensional arc model has been used to investigate the effects of the various forces acting on the droplet in gas metal arc welding (GMAW). The model is based on the equations of conservation of mass, energy, momentum and current, Ohm's law and a Maxwell equation. The model treats the welding wire, the plasma and the workpiece. For molten metal droplets at the tip of the welding wire, we account for effects of inertia, gravity, surface tension, magnetic force, viscous drag force and arc pressure. Calculations are presented for a 1.6 mm diameter wire of mild steel for arcs in argon to determine the separate effects of these forces on droplet formation. It is found that, for arcs in pure argon at currents around the transition from the globular transfer mode to the spray transfer mode, viscous drag and arc pressure effects are approximately self-cancelling. It is also found that forces have a much larger effect than do forces on the transition from globular to spray modes of metal transfer.
76 citations
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TL;DR: In this paper, low-cost and no-cost substrate release mechanisms that allow gas metal arc weld 3-D printed ER4043 aluminum and ER70S-6 steel parts to be removed from a reusable print substrate with minimal energy were investigated.
76 citations