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Introduction
Published in P. Chakravarthy, M. Agilan, N. Neethu, Flux Bounded Tungsten Inert Gas Welding Process, 2019
P. Chakravarthy, M. Agilan, N. Neethu
In gas metal arc welding (GMAW), the arc is established between a consumable electrode and the workpiece. The electric arc and the molten metal are shielded by inert gases (Ar and He) and CO2. GMAW uses the direct current electrode positive (DCEP) mode to obtain a stable arc, smooth metal transfer and good weld penetration. Constant arc voltage characteristic is normally employed in GMAW. In this process, molten metal from the electrode to the weld pool can be transferred by three basic transfer modes, namely, short circuiting, globular and spray transfer. Short circuiting transfer occurs with low current and while employing an electrode of smaller diameter. When the molten metal from the electrode tip touches the weld pool surface, short circuiting occurs. This mode is preferred for welding thin sections and out-of-position (overhead) welding. Globular transfer takes place when the metal drop size is greater than the electrode diameter, and under the influence of gravity, the droplet detaches from the electrode and transfers to the weld pool. Spray transfer occurs at a high current level, wherein electromagnetic forces cause the small discrete metal drops to move through the arc gap. Spray transfer mode is more stable and produces welds more spatter-free than the globular mode. GMAW is widely used for welding of aluminium alloys, and a high deposition rate can be achieved for welding thicker sections at a higher welding speed.
G
Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
gas metal arc welding (GMAW) a welding process that produces coalescence of metals by heating them with an arc between a consumable filler metal electrode and the parts to be joined. The process is used with shielding gas and without the application of pressure. gas substation an electric power substation in which the conductors are insulated from each other and the ground by a high-pressure gas, generally sulfur hexaflouride.
Manufacturing Processes
Published in Quamrul H. Mazumder, Introduction to Engineering, 2018
Gas metal arc welding (GMAW) is a welding process that joins metals by heating them to their melting point with an electric arc. The arc is between a continuous, consumable electrode wire and the metal being welded. The arc is shielded from contaminants in the atmosphere by a shielding gas. GMAW can be performed in three different ways: Semiautomatic Welding The equipment controls only the electrode wire feeding. Movement of the welding gun is controlled by hand. This may be called handheld welding.Machine Welding—It uses a gun that is connected to a manipulator of some kind (not hand-held). An operator has to constantly set and adjust controls that move the manipulator.Automatic Welding—It uses equipment that welds without the constant adjustment of controls by a welder or operator. On some equipment, automatic sensing devices control the correct gun alignment in a weld joint.
GMAW power supply based on parallel full-bridge LLC resonant converter
Published in International Journal of Electronics, 2022
Kaiyuan Wu, Yifei Wang, Xuanwei Cao, Jiatong Zhan, Xiaobin Hong, Tong Yin
Welding is an essential process in the manufacturing industry and major advances in many fields cannot be separated from developments in welding technology. Gas metal arc welding (GMAW) is one of the most common welding methods. At present, two main circuit topologies are used in GMAW power supply: traditional hard-switching and phase-shift full-bridge (PSFB) soft switching. The traditional hard-switching topology offers the advantages of a simple structure and large output power but suffers from low efficiency and high electromagnetic interference (EMI) (Erickson, 2001). In contrast, the PSFB soft-switching topology can partially realise zero-voltage switching (ZVS) or zero-current switching (ZCS) through phase-shift control of the pulse width modulation (PWM) and can improve the energy conversion efficiency within a certain range. However, implementing soft switching for the lagging bridge under light loads is difficult with the PSFB converter and serious duty cycle losses occur under heavy loads (Koo et al., 2005; Tah & Lakshmi, 2019). Aksoy (2014) proposed a welding power supply with PSFB as the main circuit topology and through simulations and experiments, showed that the welding process is steadily performed with an efficiency of 83% at a rated output of 5 kW.
Experimental evaluation of longitudinal tensile properties of ferritic stainless-steel weldment joined by metal inert gas, pulse metal inert gas, and tungsten inert gas welding
Published in Welding International, 2022
Shahid Hussain, Ajai Kumar Pathak
MIG welding is also known as gas metal arc welding (GMAW). In this process, an arc is produced between a continuously feeding electrode wire and a workpiece. The molten weld pool and electric arc are protected through shielding gases. Based on welding conditions and workpiece material, the shielding gas may be selected as helium, argon, nitrogen, or their mixture [9]. In MIG welding, due to arc instability, pure argon as a shielding gas is not preferred. Argon with 2% carbon dioxide or 2% oxygen may be employed for the welding of FSS base materials to overcome this problem of arc instability [10]. The molten metal from the consumable electrode tip may be transferred to the weld pool through three fundamental transfer techniques, namely spray, globular, and short-circuit. MIG welding setup provides deep penetration, high welding speed, and high heat input [11].
Effect of electrode wire surface integrity and surface oxides on the stability of gas metal arc welding
Published in Welding International, 2021
Brajesh Asati, Akhil Kishore V T, Nikhil Shajan, Kanwer Singh Arora, Anoj Giri
Gas metal arc welding (GMAW) is the most commonly used arc welding process in various industries viz. automotive, railways, heavy engineering, and fabrication. It offers advantages like productivity, ease of automation, and wide range of consumables [1–4]. With the increasing use of high speed welding, arc stability is a key challenge [5]. Primary process parameters like wire feed speed (i.e. welding current) and corresponding arc voltage determine metal transfer mode during welding. Secondary parameters like contact-tip to work distance (CTWD) and electrode stick-out fine tunes the arc characteristic. In addition, the type of power source, shielding gas composition, and consumable wire are factors that influence the welding arc stability and mode of metal transfer [6,7].