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 correlation of the heat flux on the anode surface with the plasma properties at the free-fall edge was developed by using the models of the tungsten inert gas (TIG) welding arc and anode boundary layer.
36 citations
TL;DR: In this article, the effect of shielding gas on the penetration, defects, and mechanical properties of the hybrid weld beads was investigated using either 80%Ar-20% CO2 or 100%CO2 shielding gas.
Abstract: In this study, high-power disk laser–metal active gas arc hybrid welding was performed on thick plates of high-tensile-strength steel, HT780. The effect of shielding gas on the penetration, defects, and mechanical properties of the hybrid weld beads was investigated using either 80 %Ar–20 %CO2 or 100 %CO2 shielding gas. The results showed that the process window of laser powers for the production of sound welds was wider in 100 %CO2 gas, although more spatters occurred. Besides, the optimization of the arc parameters could reduce spattering significantly by controlling the globular transfer mode to form a buried arc. The Vickers hardness test was performed to identify the levels of hardening and softening in the bead and HAZ, respectively. The tensile test results showed that the tensile strengths of the joints hybrid-welded in either 80 %Ar–20 %CO2 or 100 %CO2 gas were much higher than those of the HT780 base material. The Charpy V-notch test results revealed that the values of the hybrid-welded joints in 80 %Ar–20 %CO2 gas were higher than those in 100 %CO2 gas. The reduction in toughness was attributed to the increase in the oxygen content and the consequent formation of a higher number of oxides in a weld bead made in 100 %CO2 gas.
36 citations
TL;DR: A series of emission spectroscopy of arc plasma for TIG welding for magnesium with normal wire and activated flux coated wire is developed in this paper, where the effect of the fluxes on the weld penetration of the magnesium alloy is examined.
Abstract: The activated flux coated wires are used to examine the effect of the fluxes on the weld penetration of the magnesium alloy. A series of emission spectroscopy of arc plasma for TIG welding for magnesium with normal wire and activated flux coated wire are developed. It is found that intensities of emission spectra of Mg I increase significantly when the flux wires are used. All the flux coated wire can increase the weld penetration of the TIG welding. The electron temperature and electron density of welding plasma are estimated. The result indicated that the electron temperature of arc plasma decrease when the flux coated wires are used; on the contrary, the electron density of the plasma got enhanced. It is believed that the current density increases with the electron density increase, which is one of the reasons that the penetration depth increase when the flux wires are used.
36 citations
TL;DR: In this paper, a unified arc model for gas metal arc welding, including metal transfer, is presented, which does not account for heat transfer in the metal, but the wire melting rate is determined by the arc current.
Abstract: The gas metal arc welding (GMAW) process combines aspects of arc plasma, droplet transfer, and weld pool phenomena. In the GMAW process, an electrode wire is melted by heat from an arc plasma, and molten metal at the wire tip is deformed by various driving forces such as electromagnetic force, surface tension, and arc pressure. Subsequently, the molten droplet detaches from the tip of the wire and is transferred to the base metal. The arc plasma shape changes together with the metal transfer behavior, so the interaction between the arc plasma and the metal droplet changes from moment to moment. In this paper, we describe a unified arc model for GMAW, including metal transfer. In the model, we do not account for heat transfer in the metal, but the wire melting rate is determined by the arc current. The developed model can show transition from globular transfer at low currents to spray transfer at higher currents. It was found that electromagnetic force is the most important factor at high currents, but surface tension is more important than electromagnetic force at low currents in determining the transfer mode.
36 citations
Journal Article•
TL;DR: In this paper, the authors compared the heat input of the welding arc, calculated from the measured values for voltage and current, is compared to the heat gained by the weldment for pulsed and nonpulsed current welding.
Abstract: In this work, the heat input of the welding arc, calculated from the measured values for voltage and current, is compared to the heat gained by the weldment for pulsed and nonpulsed current welding. The effects of shielding gas composition, arc length, weld geometry and weld position on heat transfer are examined. Methods for calculating the heat received by the weld during pulsed current welding are discussed
36 citations