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.

Numerical simulation of WAAM process by a GMAW weld pool model

Abstract: Additive manufacturing (AM) is a high-productivity process which can make a near-net-shape structure. In this study, the focus is the wire-arc AM (WAAM) process. In the WAAM process, wire is the depositing material. The wire melts by an arc plasma and deposits layer by layer. To establish an advanced WAAM process, it is important to make a precise structure of the intended shape. In this study, a gas metal arc welding (GMAW) weld pool model is applied to WAAM process, and influence of the deposit condition on the shape of the deposition is numerically investigated. Firstly, influence of the interpass temperature is investigated. When cooling time is set appropriately, the deposition shape becomes higher and thinner. In addition, concerning influence of the welding direction, when the welding direction is reversed for each layer, the variance of the deposition height becomes small. These numerical results show that it is important to manage the temperature and torch motion for controlling the deposition shape. These numerical results have similar tendency with experimental results and show the GMAW weld pool model is a helpful tool to predict and control the WAAM process.

Resistance welding monitor

Abstract: A welding voltage output from a power source of a resistance welder is derived on the basis of a welding current and an interelectrode voltage, and diameter of a nugget which is formed in a sheetlike work to be welded is estimated on the basis of the welding current, the welding voltage, data of material constant and a thickness of the sheetlike work, subsequently, the estimated diameter of nugget is composed with a target diameter of nugget, and thereby quality of the resistance welding is determined.

Effect of welding process on the microstructure and properties of dissimilar weld joints between low alloy steel and duplex stainless steel

Abstract: To obtain high-quality dissimilar weld joints, the processes of metal inert gas (MIG) welding and tungsten inert gas (TIG) welding for duplex stainless steel (DSS) and low alloy steel were compared in this paper. The microstructure and corrosion morphology of dissimilar weld joints were observed by scanning electron microscopy (SEM); the chemical compositions in different zones were detected by energy-dispersive spectroscopy (EDS); the mechanical properties were measured by microhardness test, tensile test, and impact test; the corrosion behavior was evaluated by polarization curves. Obvious concentration gradients of Ni and Cr exist between the fusion boundary and the type II boundary, where the hardness is much higher. The impact toughness of weld metal by MIG welding is higher than that by TIG welding. The corrosion current density of TIG weld metal is higher than that of MIG weld metal in a 3.5wt% NaCl solution. Galvanic corrosion happens between low alloy steel and weld metal, revealing the weakness of low alloy steel in industrial service. The quality of joints produced by MIG welding is better than that by TIG welding in mechanical performance and corrosion resistance. MIG welding with the filler metal ER2009 is the suitable welding process for dissimilar metals jointing between UNS S31803 duplex stainless steel and low alloy steel in practical application.

Welding of 316L Austenitic Stainless Steel with Activated Tungsten Inert Gas Process

Abstract: The use of activating flux in TIG welding process is one of the most notable techniques which are developed recently. This technique, known as A-TIG welding, increases the penetration depth and improves the productivity of the TIG welding. In the present study, four oxide fluxes (SiO2, TiO2, Cr2O3, and CaO) were used to investigate the effect of activating flux on the depth/width ratio and mechanical property of 316L austenitic stainless steel. The effect of coating density of activating flux on the weld pool shape and oxygen content in the weld after the welding process was studied systematically. Experimental results indicated that the maximum depth/width ratio of stainless steel activated TIG weld was obtained when the coating density was 2.6, 1.3, 2, and 7.8 mg/cm2 for SiO2, TiO2, Cr2O3, and CaO, respectively. The certain range of oxygen content dissolved in the weld, led to a significant increase in the penetration capability of TIG welds. TIG welding with active fluxes can increase the delta-ferrite content and improves the mechanical strength of the welded joint.