Gas Metal Arc Welding

This paper presents a relatively new method for achieving better welding results of gas metal arc welding (GMAW) system by using a decentralized control method. The GMAW system is an arc welding process which incorporates the power source of GMAW (PS-GMAW) with the ...

The arc sound was found to be strongly related to both process parameters and weld quality, like voltage and current signals, in gas metal arc welding. In this investigation, the acquired welding arc sound signal along with current and voltage signals were analyzed in time domain as ...

Advancements in Intelligent Gas Metal Arc Welding Systems: Fundamentals and Applications presents the latest on gas metal arc welding which plays a significant role in modern manufacturing industries and accounts for about 70% of welding processes. The importance of advancements in GMAW cannot be underestimated as they can lead to more efficient production strategies, resource savings and quality improvements. This book provides an overview of various aspects associated with GMAW, starting from the theoretical basis and ending with characteristics of industrial applications and control methods. Additional sections cover processes associated with welding and welding control, such as fuzzy logic, artificial neural networks, and others.

Iron-based hardfacing alloys are widely used to protect machinery equipment exposed either to pure abrasion or to a combination of abrasion and impact. The specific wear behaviour of a welding alloy under these conditions depends on its chemical composition, the microstructure obtained after welding and finally the welding technology used to apply them respectively the parameter settings which strongly influence,

This study has been aimed to find out the proper welding procedure/conditions for a newly developed Fe-16Cr-1Ni-9Mn-0.12N austenitic stainless steel (ASS), which is uniquely modified from 200 series alloy, in order to control the microstructural metastability of the weld metals. The welded joints of 4 mm thick sheet were prepared in a square butt configuration by using three modes of metal transfer, i.e., short-circuit (SC), spray (S), and pulse (P) mode of metal transfer and three austenitic filler metals (304L, 308L and 316L) under two shielding gas environments using gas metal arc welding (GMAW) process. It is observed that the variation in modes of metal transfer and filler metals can effectively manipulate the metastability of γ-phase, formation of δ-phase and grain size of the weld metals. Among the modes of metal transfer, pulse mode of metal transfer produces more me-tastable γ-phase and higher δ-phase fraction responsible for finer grain structure in weld metals irrespective of filler metals used. Again, higher microstructural metastability was obtained with the 304L filler metal irrespective of modes of metal transfer used. It is evident that the weld metals having higher microstructural me-tastability also improved mechanical properties (i.e. hardness, strength and toughness). However, weak fusion boundary (FB) region of welded joint limits the beneficial effect of metastability and creates a weakest link in the joint. On the other hand, high temperature heat affected zone (HTHAZ) having a coarse austenite grain surrounded by grain boundary precipitates is governed only by the modes of metal transfer.

Purpose – The purpose of this paper is to present original methods related to the modeling of material deposit and associated heat sources for finite element simulation of gas metal arc welding (GMAW). Design/methodology/approach – The filler deposition results from high-frequency impingements of melted droplets. The present modeling approach consists of a time-averaged source term in the mass equation for selected finite elements in the fusion zone. The associated expansion of the mesh is controlled by means of adaptive remeshing. The heat input includes a volume source corresponding to the droplets energy, for which a model from the literature is expressed in coherency with mass supply. Finally, an inverse technique has been developed to identify different model parameters. The objective function includes the differences between calculations and experiments in terms of temperature, but also shape of the fusion zone.
Findings – The proposed approach for the modeling of metal deposition results in a direct calculation of the formation of the weld bead, without any a priori definition of its shape. Application is shown on GMAW of steel 316LN, for which parameters of the model have been identified by the inverse method. They are in agreement with literature and simulation results are found quite close to experimental measurements. Originality/value – The proposed algorithm for material deposit offers an alternative to the element activation techniques that are commonly used to simulate the deposition of filler metal. The proposed inverse method for parameter identification is original in that it encompasses an efficient and convenient technique to take into account the shape of the fusion zone.

Shielded metal arc welding (SMAW) is the world's most popular welding process. In this process consumable electrode is used for generating arc. The electrode is coated with a shielding flux. The flux melts with the electrode metallic core, forming gas and slag, shielding the arc and the weld pool. The flux cleans the metal surface and protects the molten metal from oxidation and stabilizes the arc. The molten electrode metal then fills the weld gap and joins work pieces. This is the most popular welding process having ability to produce a great variety of welds using variety of metals, welding positions and electrodes. SMAW equipment is simple, portable, inexpensive and suitable for outdoor applications. SMAW is generally used to weld carbon steel, low and high alloy steels, stainless steel, cast iron, and ductile iron. While less popular for nonferrous materials, it can be used on nickel and copper and their alloys and, in rare cases on aluminium. This paper reviews based on SM...

Welds were made with a 1.2-mm-diameter AWS ER100S-1 electrode using Ar-2% O[sub 2] shielding gas to map the effects of contact-tube-to-work distance (13, 19 and 25 mm), current, voltage, and wire feed rate on metal transfer. The droplet transfer modes were identified for each map by both the sound of the arc and images from a laser back-lit high-speed video

Welding with fusible electrode and shielding gas (GMAW) using a shielding mixture based on CO2+ O2 is a procedure with high potential for joining low-carbon and low-alloy steels compared with traditional mixtures based on argon. One of the reasons for this is related ...

DOE Scientific ... Publication Date, 1997 Jan 03. OSTI Identifier, OSTI ID: 486147; Legacy ID: DE97003116. Report Number(s), CONF-970726--3. DOE Contract Number, AC05-96OR22464. DOI, 10.2172/486147. Other Number(s), Other: ON: DE97003116; TRN: TRN: AHC29713% ...

Abstract Additive manufacturing (AM) route is a promising approach for fabricating complex and lightweight metallic structures that have applications in various sectors such as automotive, aerospace, and biomedical industries. Laser, electron beam, and electric arc are the common power sources available for AM. Out of different metal AM techniques, wire-feed additive manufacturing has been considered as a promising alternative for fabricating metallic parts for various applications. As it provides a high deposition rate, material utilization, density, and low cost with a low risk of contamination and porosity compared to powder-based raw material. Gas metal arc welding-based additive manufacturing (GMAW-AM) is a specific approach based on wire-feed AM. This technology uses a low-cost equipment which is suitable for fabricating components with large geometries and moderate structural complexity. These advantages attract the researchers and production industries for further developments in GMAW-AM to enhance its deposition performance, process capability, and applicability in various fields. The quality of metal deposited in GMAW-AM is generally represented by the surface form, dimensional quality, mechanical properties, relative density, hardness, etc. The present paper encompasses the research developments that occurred in the field of GMAW-AM in recent years. This review begins with the GMAW-AM procedure, performance capability, identification of factors affecting the deposition performance, and strategies adopted to overcome these issues. Several aspects such as mathematical modelling, optimization, key process parameters, and their combinations for a wide range of wire electrode material and percentage contributions are also reviewed and depicted in detail. Also, a comprehensive conclusion of this review, along with future perspectives, is explored subsequently. The current review work will help future researchers to select different wire materials and GMAW-AM parameters to achieve better performances. Lastly, several future research directions are suggested, specifically the need of a framework for GMAW-AM processes for fabricating quality products with minimum distortion.

The profile of the welding bead changes with the welding process parameters during the gas metal arc welding (GMAW) process, the top reinforcement disappears, and the penetration becomes sunken when the excessive welding heat input is applied. However, little research work is specially planned to cope with the studying of welding bead under these circumstances. A systematic study of the relationships among the welding process variables and welding bead geometric features as well as optimization of the welding quality is presented. The influences of the welding technological parameters (voltage, welding speed, and wire feed speed) on the welding geometry were revealed, and the models correlating them were established. The features of the weld bead geometry were composed of top reinforcement width, top reinforcement height, penetration depth, bottom reinforcement width, and bottom reinforcement height. By the desirability function approach, the recommendation of suitable welding parameters to meet the contradicting demands of multiple bead geometric features is fulfilled. The microstructure in different welding regions and mechanical performances of the welding joints produced by the verification test were also studied.

Plasma arc welding (PAW)-cable-type seven-wire GMAW (gas metal arc welding) hybrid welding is known as a high-efficiency welding combining plasma arc, GMAW arc and cable-type welding wire. In this study, numerical simulation via Fluent of the molten pool temperature field and flow field and experimental verification were conducted on Q235 thin plate hybrid welding with cable-type wire to explore molten pool fluid behavior. The simulation results show that keyholes form in the molten pool due to the strong penetration ability of a plasma arc and then the evolved pores by the surface tension float out of the molten pool. When the GMAW welding current increases, both the length and width of the weld pool enlarge, the weld reinforcement increases and the flow rate of molten metal in the weld pool also speeds up. While the PAW current increases, the weld pool length also increases and the molten metal in the weld pool significantly flows faster, but the weld reinforcement decreases. When...

In the first step, we present the preparation feature, which will consist of the welding achievement, considering the type of assembly, feature geometry and parameters of welding process. The focus is only on butt-welded assembly using a gas metal arc welding ...

Residual stress induced deformations are a major cause of loss in tolerances in solid freeform fabrication processes employing direct metal deposition. In this paper a 2D finite element thermo-mechanical model is being presented to predict the residual stress induced deformations with application to processes where material is added using a distributed, moving heat source. A sequentially coupled thermo-mechanical analysis is

Respiratory effects observed in welders have included lung function changes, metal fume fever, bronchitis, and a possible increase in the incidence of lung cancer. Many questions remain unanswered regarding the causality and possible underlying mechanisms associated with the potential toxic effects of welding fume inhalation. The objective of the present study was to construct a completely automated, computer-controlled welding fume

Avoiding short circuit is an essential condition for achieving good quality welds in Pulse Gas Metal Arc Welding (GMAW-P). Estimating short circuit in any welding process is dependent on proper selection and optimization of welding process parameters. Such optimization is critical in the GMAW-P wherein wire melting is closely dictated by numerous pulsing parameters in comparison to the conventional GMAW