Topic
Shielding gas
About: Shielding gas is a research topic. Over the lifetime, 6697 publications have been published within this topic receiving 58668 citations.
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TL;DR: In this paper, the effects of shielding gas composition on the amount and composition of welding fumes produced during gas metal arc welding (GMAW) were measured for steady current over a range of wire-feed speeds and arc voltages using the standard procedures contained in ANSI/AWS F1.2.
Abstract: The control of exposure to welding fumes is of increasing importance in promoting a healthy, safe and productive work environment. This article describes the effects of shielding gas composition on the amount and composition of welding fumes produced during gas metal arc welding (GMAW). The amount of fumes generated during welding was measured for steady current over a range of wire-feed speeds and arc voltages using the standard procedures contained in ANSI/AWS F1.2 [American Welding Society. ANSI/AWS F1.2. Laboratory method for measuring fume generation rates and total fume emission of welding and allied processes. Miami, Florida; 1992]. Results of these measurements show that the fume formation rates (FFRs) increase with CO2 and O2 in the shielding gas mixture. The lowest FFRs were obtained with the mixtures of Ar + 2%CO2 and Ar + 3%CO2 + 1%O2. The highest FFRs were obtained with the mixtures of Ar + 18%CO2 and Ar + 5%CO2 + 4%O2. The welding fumes contains mainly iron, manganese, silicon, titanium and ...
67 citations
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TL;DR: In this paper, the effects of various gas metal arc welding (GMAW) and universal GMAW process parameters on dilution in single layer stainless steel cladding of low carbon structural steel plates were analyzed.
67 citations
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TL;DR: In this article, it was shown that oxides have two different effects: one on the fusion zone chemistry and the other on the electric arc behavior, and it was established that the oxide effects by Marangoni convection appeared for a critical value of the welding energy.
Abstract: Activated tungsten inert gas (TIG) welding, which involves the deposition of an inorganic powder on the metal surface prior welding, improves TIG welding performances in terms of weld bead penetration. Most common commercial fluxes contain halides and oxides. The present paper focuses on fluxes made of oxides. It appears that oxides have two different effects: one on the fusion zone chemistry and the other on the electric arc behaviour. First, oxygen reverses the Marangoni convection movements that become centripetal, contributing thus to increase 'D' penetration. On the other hand, oxides may cause an increase in the energy flux density transferred by the arc to the metal. The characterisation of the arc plasma by optical emission spectroscopy suggests that oxides do not increase the arc temperature. It is established that the oxide effects by Marangoni convection appear for a critical value of the welding energy, whereas the oxide effects on the electrical arc exist irrespective of the welding e...
66 citations
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03 Apr 1989
TL;DR: In this article, a welding gun with a motor mounted on the welding block and a barrel through which welding wire is fed by drive rollers turned by the motor is described. But the motor was mounted within a removable casing that encloses the block, motor, and speed control mechanism.
Abstract: Disclosed is a welding gun which includes a mounting block, a motor mounted to the welding block and a barrel through which welding wire is fed by drive rollers turned by the motor. There is a passageway through the welding block which has a valve therein for controlling the flow of a shielding gas through the passageway and through the barrel. A speed control mechanism device is mounted within a removable casing that encloses the block, motor, and speed control mechanism. The speed control includes a knob which is turned by the welder and includes a tactile response element that better enables the welder to determine the correct setting for the desired speed of the wire even though wearing a glove.
66 citations
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TL;DR: The welding flux for each of these processes must meet specific physical and chemical requirements to perform properly as discussed by the authors, and the flux viscosity is important because it controls the extent to which the flux can chemically alter the weld-metal composition, and it influences weld metal porosity, bead morphology, and the ability to make out-of-position weld deposits.
Abstract: Shielded-metal arc, submerged arc, and flux-cored arc welding processes (1) all rely on a flux to achieve an acceptable weld deposit. The welding flux for each of these processes must meet specific physical and chemical requirements to perform properly (2). A flux must have a melting range such that the weld metal solidifies before the molten slag does, and the resulting slag must have a density such that it floats to the top of the weld pool and collects there. The specific ranges of melting and density vary depending on the alloy being welded. The flux must also assist in main taining the arc plasma, in producing a shielding gas to protect the weld deposit from the atmosphere, and in limiting the amount of splatter. The flux viscosity is important because it controls the extent to which the flux can chemically alter the weld-metal composition, and it influences weld metal porosity, bead morphology, and the ability to make out-of-position weld deposits (3, 4). The flux must contain specific chemical additions to influence the weld metal's composition, microstructure, and properties.
66 citations