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Laser cuts time to completion at vosper thornycroft
About: This article is published in Welding and metal fabrication.The article was published on 1996-01-01 and is currently open access. It has received 18 citations till now.
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TL;DR: In this article, the effect of flux on the flow and temperature fields of weld pool is simulated by the PHOENICS software, which shows that without flux, the fluid flow will be outward along the surface of the weld pool and then down, resulting in a flatter weld pool shape.
Abstract: The mechanism of the increasing of A-TIG welding penetration is studied by using the activating flux we developed for stainless steel. The effect of flux on the flow and temperature fields of weld pool is simulated by the PHOENICS software. It shows that without flux, the fluid flow will be outward along the surface of the weld pool and then down, resulting in a flatter weld pool shape. With the flux, the oxygen, which changes the temperature dependence of surface tension grads from a negative value to a positive value, can cause significant changes on the weld penetration. Fluid flow will be inward along the surface of the weld pool toward the center and then down. This fluid flow pattern efficiently transfers heat to the weld root and produces a relatively deep and narrow weld. This change is the main cause of penetration increase. Moreover, arc construction can cause the weld width to become narrower and the penetration to become deeper, but this is not the main cause of penetration increase. The effects of flux on fluid flow of the weld pool surface and arc profiles were observed in conventional TIG welding and in A-TIG welding by using high-speed video camera. The fluid flow behavior was visualized in realtime scale by micro focused X-ray transmission video observation system. The result indicated that stronger inward fluid flow patterns leading to weld beads with narrower width and deeper penetration could be apparently identified in the case of A-TIG welding. The flux could change the direction of fluid flow in welding pool. It has a good agreement with the simulation results.
39 citations
TL;DR: In this article, an integrated approach using the Taguchi method, artificial neural network (ANN), and genetic algorithm (GA) was proposed to optimize the weld bead geometry of gas tungsten arc (GTA) welding specimens.
Abstract: Many parameters affect the quality of the gas tungsten arc (GTA) welding process. It is not easy to obtain optimal parameters of the GTA welding process. This paper applies an integrated approach using the Taguchi method, artificial neural network (ANN), and genetic algorithm (GA) to optimize the weld bead geometry of GTA welding specimens. The proposed approach consists of two stages. First stage executes initial optimization via Taguchi method to construct a database for the ANN. In second stage, an ANN is used to provide the nonlinear relationship between factors and the response. Then, a GA is applied to obtain the optimal factor settings. The experimental results showed that the weld bead geometry of the optimal welding parameters via the proposed approach is slender than apply Taguchi method only.
37 citations
TL;DR: In this paper, the influence of specific flux powders, including FeF2, FeO, and FeS, on the surface appearance, geometric shape, angular distortion, hot crack susceptibility, and metallurgical properties of 5-mm-thick 17Cr-10Ni-2Mo alloys welded using the tungsten inert gas (TIG) process was investigated.
32 citations
TL;DR: In this article, the effect of active oxide fluxes with gas tungsten arc welding on the microstructure and mechanical properties of AZ31B magnesium alloy weldment was investigated.
Abstract: In this study, the effect of active oxide fluxes with gas tungsten arc welding on the microstructure and mechanical properties of AZ31B magnesium alloy weldment was investigated. The gas tungsten arc welding process through a flux spray layer was applied to an AZ31B magnesium alloy sheet to produce a bead-on-plate specimen. Oxide (TiO2, SiO2, Fe2O3, Al2O3, and ZrO2) powders were used as the activating fluxes. The macrographs and micrographs of the weld beads were examined using an optical microscope and a scanning electron microscope. The specimens with SiO2 and Fe2O3 fluxes had high depth-to-width ratio welds, followed by those with TiO2 and ZrO2 fluxes and while that with Al2O3 flux had the low ratio weld. The use of 70 A welding current for the specimens with different fluxes produced complete penetration, whereas the specimen without any flux required a 90 A welding current to produce complete penetration. The weld bead microstructure was affected by the activating fluxes, which created different ther...
16 citations
TL;DR: In this article, the weld bead geometry of 6061 aluminum alloy welds pre-coated with activating flux before gas metal arc (GMA) welding was optimized to obtain the optimal welding parameters that were considered with multiple quality characteristics such as penetration, depth-to-width ratio (DWR) and fusion area of GMA welds.
Abstract: We optimized the weld bead geometry of 6061 aluminum alloy welds pre-coated with activating flux before gas metal arc (GMA) welding. In this activated GMA welding process, there were five single component fluxes used in the initial experiment to evaluate the penetration capability of bead-on-plate GMA welds. Based on the higher penetration of weld bead, two single component fluxes were selected to create mixed component flux in next stage. The grey-based Taguchi method was employed to obtain the optimal welding parameters that were considered with multiple quality characteristics such as penetration, depth-to-width ratio (DWR) and fusion area of GMA welds. The experimental procedure of the proposed approach not only increases penetration of 6061 aluminum alloy welds, but also improves the DWR and fusion area of GMA butt-joint welds simultaneously.
14 citations