Search Results (37)

Weld quality plays a critical role in ensuring the structural integrity and long-term performance of critical piping systems used across petrochemical, oil and gas, marine, and healthcare sectors. Although gas tungsten arc welding, shielded metal arc welding, and gas metal arc welding are widely applied in pipe fabrication, existing studies often examine these processes independently and provide limited insight into the comparative influence of process parameters on weld morphology, microstructure, and mechanical performance. This review consolidates findings from recent research to evaluate how welding current, arc voltage, heat input, travel speed, shielding gas composition, and joint preparation interact to affect weld bead geometry, heat-affected zone evolution, tensile properties, hardness, and overall weld integrity in piping systems. The primary objective of this review is to critically compare fusion welding process parameter optimization strategies and to identify unresolved challenges in achieving controlled weld root geometry for high-integrity piping applications. Recent industrial failure investigations, particularly in ethylene oxide service piping, further underscore the importance of weld root control. Several documented leak events were traced to excessive root protrusion and inadequate interpretation of non-destructive testing data, where elevated reinforcement disrupted internal flow and promoted turbulence-induced degradation. These recurring issues highlight a broader industry challenge and strengthen the need for improved root-height optimization in critical piping applications. A significant research gap is identified in the limited optimization of weld root reinforcement, particularly in gas tungsten arc welding processes, where most reported studies document root heights exceeding 3 mm. Achieving a root height below 2 mm, which is an important requirement for reducing flow-induced turbulence and meeting industry acceptance criteria, remains insufficiently addressed. This review highlights this gap and outlines future research opportunities involving advanced parameter optimization and improved process monitoring techniques. The synthesis presented here provides a comprehensive reference for enhancing weld quality in critical piping systems and establishes a pathway for next-generation welding strategies aimed at producing high-integrity weld joints compliant with the American Society of Mechanical Engineers B31.3 requirements. Full article

This study investigates the chemical composition, microstructural evolution, and mechanical behavior of hardfacing coatings produced by Shielded Metal Arc Welding (SMAW) using electrodes with varying niobium (Nb) contents (0%, 2%, 4%, 6%, and 8%), deposited at a constant current of 120 A and employing two- and three-layer configurations. Optical Emission Spectroscopy (OES) revealed a significant reduction in niobium transfer efficiency, with the Nb content in the coatings reaching up to 3.5 wt%, approximately 50% lower than in the electrodes. Chromium (Cr) content also decreased with increasing Nb additions due to the higher thermochemical affinity of niobium for oxygen, which promotes the formation of Nb oxides during welding. X-ray diffraction (XRD) analyses confirmed the presence of complex carbides, primarily NbC and M₇C₃-type Cr carbides, embedded in eutectic austenitic matrices. The incorporation of niobium promoted grain refinement and the precipitation of primary NbC carbides, particularly in multilayer coatings where dilution effects were reduced. Scanning Electron Microscopy (SEM) and Energy-Dispersive Spectroscopy (EDS) provided additional evidence, revealing an increased density of NbC particles and a concomitant reduction in CrC particle size with higher Nb contents. Microhardness testing showed a slight increase in hardness with increasing niobium, attributed to the higher intrinsic hardness and finer size of NbC particles. Overall, these findings highlight the role of niobium as an effective grain refiner and hard-phase promoter in SMAW-applied coatings, providing a foundation for optimizing wear-resistant overlays for demanding industrial environments. Full article

This paper presents the design, development, and preliminary validation of a haptic virtual reality simulator for Shielded Metal Arc Welding (SMAW) at the Pontificia Universidad Católica de Valparaíso, Chile, aimed at enhancing psychomotor training for mechanical engineering students in line with Industry 4.0 demands. The system integrates Unity 3D, a commercial haptic device, and a custom 3D-printed electrode holder replicating the welding booth, enabling interaction through visual, auditory, and tactile feedback. Thirty students with minimal welding experience and seven experts participated in usability and realism assessments. The results showed that 80% of students perceived motor skill improvement, 60% rated realism as adequate, and 90% preferred hybrid training (simulator + workshop). The prototype was practically implemented at the mechanical engineering school, requiring only a mid-range workstation, the Touch haptic device, and the developed software, demonstrating feasibility in real academic settings. The findings indicate potential to build confidence, support motor coordination, and provide a safe, resource-efficient training environment, while experts emphasized the need for automated feedback and improved haptic fidelity. The modular architecture allows scalability, extension to other welding processes, and adaptation for inclusive education. This prototype demonstrates how locally developed immersive technologies can modernize technical education while promoting sustainability, accessibility, and skill readiness. Full article

This investigation examines the corrosion behavior and mechanisms of 304 stainless steel shielded metal arc welding (SMAW) and gas metal arc welding (GMAW) joints in the simulated reservoir environment through electrochemical testing, stress-free hanging specimens and U-bend specimen immersion experiments, and microstructural characterization. The electrochemical results demonstrate that both welded joints exhibit a superior corrosion resistance in this environment, with a sensitivity of intergranular corrosion (IGC) below 1% and a corrosion rate below 0.005 mm/a. Increasing chloride concentrations elevate the passivation current densities for both the base metal and welded joints. The immersion testing revealed that after 90 days of exposure across the investigated chloride concentrations (50–300 mg/L), all welded specimens maintained surface integrity with no visible corrosion. Furthermore, U-bend specimens demonstrated no evidence of stress corrosion cracking, confirming a low stress corrosion susceptibility. Full article

The present work is a comparative analysis of the properties of welded joints obtained during welding with the developed welding electrodes containing additives of photocatalysts of nanostructured functional ceramics (PNFC) brand ZB-1 (IMAN-7) and the ESAB E6013 welding electrodes. This study investigates the weld morphology, microstructure, and mechanical properties of Shield metal arc welding (SMAW) welded joints. The results of the studies showed that the introduction of PNFC brand ZB-1 into the coating of welding electrodes up to 1% has a beneficial effect on the melting ability and stability of the welding arc, formation of the bead, microstructure of the weld bead, and mechanical properties of the welded joints. It was found that IMAN-7 electrodes, compared to the ESAB E6013 electrodes, have better performance in terms of arc penetration, bead metal structure, and relative elongation of welded joints. In addition, the high melting capacity of the IMAN-7 electrode allows for economic advantages, such as increased productivity and a two-fold reduction in electrode consumption. Full article

Hardfacing is a welding-related technique aimed at depositing a harder and tougher layer onto a softer, less wear-resistant substrate or base metal. This process enhances the abrasion resistance of the component, increasing its durability under working conditions. A key feature of hardfacing is dilution, which refers to the mixing of the hardfacing layer and the base metal. In this study, shielded metal arc welding (SMAW) was employed to hardface structural steel using chromium carbide vanadium consumables, with results compared to AISI D2 cold-work tool steel. Four different SMAW parameters were tested, and the abrasive test was conducted against SiC discs. Wear rate, represented by the wear loss rate, was correlated to microstructure, scanning electron microscopy, energy-dispersive X-ray spectroscopy, hardness, microhardness, and surface roughness. The results showed that key SMAW parameters, such as welding speed and current, significantly influence wear resistance. Specifically, slower welding speeds and higher currents, which result in greater heat input, led to the increased wear resistance of the deposited layer through the mechanism of the inoculation of larger and harder carbides. Full article

This study explores the effect of preheating on the toughness of dissimilar welded joints between AISI 1037 and AISI 304 steels, using Shielded Metal Arc Welding (SMAW) and E309-16 electrodes. The innovation of this approach lies in assessing how preheating temperatures influence the mechanical properties of such welds. Preheating temperatures ranged from 150 °C to 300 °C, with impact testing revealing a notable increase in toughness, from 6.01 Joules at 150 °C to 19.57 Joules at 300 °C. Hardness tests indicated a maximum hardness of 313 VHN in the fusion zone and a minimum of 185 VHN in the AISI 304 area. Compared to non-preheated joints, preheating significantly enhanced impact strength and altered the fracture mode from brittle to ductile. Macrostructural and microstructural analyses with optical microscopy and SEM showcased changes in fracture surfaces and microstructural evolution, highlighting the improvement in mechanical properties due to preheating. These findings demonstrate that preheating critically enhances the toughness and overall performance of dissimilar metal welds, making it a valuable technique in industrial applications where enhanced joint toughness is crucial. Full article

Unforeseen failures in girth welds present a significant challenge for the pipeline industry. This study utilizes 3D Digital Image Correlation (DIC) assisted cross-weld tensile testing to analyze the strain response of high-strength thick-walled pipelines, providing essential insights into the strain migration and fracture mechanisms specific to girth welds. The results reveal that the welding process significantly affects the mechanical distribution within the girth weld. The tested Shielded Metal Arc Welded (SMAW-ed) pipe exhibited undermatched girth welds due to high heat input, while Gas Metal Arc Welding (GMAW) introduced a narrower weld and Heat-Affected Zone (HAZ) with higher hardness than the base metal, indicative of overmatched girth welds. Strain migration, resulting from a combination of metallurgical heterogeneous materials and geometrical reinforcement strengthening, progressed from the softer HAZ to the base metal in the SMAW-ed sample with reinforcement, ultimately leading to fracture in the base metal. In contrast, the GMAW-ed sample shows no strain migration. Reinforcement significantly improves the tensile strength of girth welds and effectively prevents failure in the weld region. Sufficient reinforcement is crucial for minimizing the risk of failure in critical areas such as the weld metal and HAZ, particularly in SMAW-ed pipes. Full article

Hardfacing is commonly used in parts recovery and in obtaining surfaces with improved properties. Within this field, it is important to analyze the effect of alloying elements on the properties of the deposited layers. One of the critical parameters affecting alloying performances in SMAW is improper arc length. This article examines the effect of the addition of niobium in different quantities (0, 2, 4, 6, and 8% by weight) to the electrode coating in Fe-Cr-C shielded metal arc welding (SMAW), with short and long arc lengths, on the operational process efficiency, dilution, arc energy, microstructure, and microhardness of the deposited layers. A decrease in operational process efficiency and dilution was found with increases in niobium content. On the other hand, it was found that adding niobium leads to a refinement in chromium carbide sizes, directly affecting the hardness of the obtained deposits. There is a direct relationship between the arc energy, with both short and long arc lengths, leading to a tendency to decrease the dilution in the obtained hardfacing. Full article

The SA516 Gr.70 steel possessing excellent toughness and plasticity has been widely used in the cryogenic field. However, the appearance of coarse bainite in the heat affected zone (HAZ) of the fusion welded joint deteriorates the toughness and ductility. In this work, 4.5 mm thick SA516 Gr.70 steel was joined using shielded metal arc welding (SMAW) and friction stir welding (FSW), respectively, and the microstructure and mechanical properties of joints were investigated in detail. The Charpy energy in the HAZ in the FSW joint was 80 J/cm², which was higher than that of the HAZ in the SMAW joint (60 J/cm²) and due to microstructure refinement. In addition, the total elongation (TE) of the SMAW joint was 17.5%, which was higher than that of the FSW joint (12.1%) and caused by a wider nugget zone with high hardness. The post-welding annealing was used to improve the toughness and ductility of the SMAW and FSW joints, and the microstructure and mechanical properties of the joints after annealing were analyzed. The toughness in the HAZ of the SMAW and FSW joints were 80 and 103 J/cm², and the TE of the SMAW and FSW joints were 18.6% and 25.2%, respectively. Finally, the as-annealed FSW joints exhibited excellent toughness and ductility. The abovementioned excellent mechanical properties were primarily attributed to the appearance of tempering martensite, decrease in dislocation density, and fine grain. Full article

To ensure and to demonstrate the mechanical integrity of a welded structure, precise ultrasonic testing (UT) is often mandatory. The importance of the link between nondestructive testing (NDT) and the assessment of structural integrity is recalled. However, it is difficult to achieve great efficiency as the welding of thick and heavy structural part produces heterogeneous material. Heterogeneity results from the welding process itself as well as from the material solidification laws. For thick components, several welding passes are deposited, and temperature gradients create material grain elongation and/or size variations. In many cases, the welded material is also anisotropic, this anisotropy being due to the metal used, for example, austenitic stainless steel. At the early stages of ultrasonic testing, this kind of welded material was considered too unpredictable, and thus too difficult to be tested by ultrasounds without possible diagnosis errors and misunderstandings. At the end of the 1990s, an algorithmic solution to predict the material organisation began to be developed using data included in the welding notebook. This algorithm or modelling solution was called MINA. This present work recalls, in a synthetic form, the path followed to create this algorithm combining the use of solidification laws and the knowledge of the order of passes in the case of shielded metal arc welding (SMAW). This work describes and questions the simplifications used to produce a robust algorithm able to give a digital description of the material for wave simulation code. Step by step, advances and demonstrations are described as well as the limitations, and ways to progress are sketched. Recent developments are then explained and discussed for modelling in the case of gas tungsten arc welding (GTAW), in addition to discussions about 3D modelling for the future. The discussion includes alternative ways to represent the welded material and challenges to continue to produce more and more convincing weld material model to qualify and to make use of UT methods. Full article

Naval vessels face multiple risks that can damage their hulls during navigation, leading to on-site repairs through the shield metal arc welding (SMAW) process and underwater wet welding (UWW). This paper presents a weldability study to identify the optimal heat input parameters to improve ASTM A131 DH36 welded joints quality, development, and sustainability. This study analyzes the influence of heat input on the microstructure and mechanical properties of underwater wet welding fillet joints welded with shield metal arc welding at 4 m water depth in a real-life environment located at the bay of Cartagena (Colombia). The methodology involves nondestructive and destructive tests, including visual inspection, fillet weld break, scanning electron microscopy (SEM), X-ray diffraction (XRD), Vickers hardness, and shear strength tests. The welds microstructure is composed of ferrite, pearlite, retained austenite, bainite, and martensite; the hardness values range from 170 HV1 to 443 HV1, and the shear strength values range from 339 MPa to 504 MPa. This indicates that high thermal inputs improve the weld quality produced by the underwater wet welding technique and can comply with the technical acceptance criteria of AWS D3.6, making them more sustainable, with less welding resources wastage and less impact on marine ecosystems. Full article

Metal welding processes, and electric arc welding in particular, constitute a key link in a production chain comprising a large number of companies. This fact, in addition to a growing trend in favour of more in-depth environmental analysis and control of industry, and the need to continue affording due consideration to the economic aspect set the stage for this study. Herein, an environmental and economic analysis is conducted of four types of electric arc welding: TIG welding with and without filler, MIG, MAG, and SMAW welding. Different types of materials are examined such as carbon steel, stainless steel, and aluminium, thus the results generate relevant comparative information on the economic and environmental impacts of choosing one type of welding over another. To this end, an experimental study was carried out: 480 test specimens were welded using different welding technologies. A series of data was collected during the welding process to inform an environmental analysis based on a Life Cycle Analysis and an economic study. The most salient results include that the TIG welding process with filler generated the greatest environmental impact due to its higher consumption of shielding gas. On the other hand, the SMAW process demonstrated the best environmental performance as categories such as Global Warming Potential; CO₂ emissions dropped by 93.29%. A key factor is the final indicator of human health, where, once again, TIG technology had the worst results, in contrast to SMAW technology, wherein impact decreased by 93.08%. On the other hand, the use of TIG technology implies a higher economic cost due to a 61.36% increase in welding time compared to the average welding technology. Full article

Arc welding processes, such as shielded metal arc welding (SMAW), metal inert gas (MIG), and tungsten inert gas (TIG), play an important role in industrial applications. To improve the efficiency of the exploitation of traditional welding systems, new technologies have been used. Virtual reality technology is one of them. The virtual reality (VR)-based welding system enables to increase the frequency of practice to help learners obtain welding experience to avoid errors that occur during actual welding processes. This paper presents a VR-based system for simulating three welding processes: SMAW, MIG, and TIG. The developed system includes hardware components and VR software installed on a computer. The change in the physical devices, such as moving the welding torch and the distance from the welding torch to the plates to generate the weld bead, will update in real time and appear on the virtual environment. The functionality of the developed system for simulating the welding processes, such as in the real welding environment, was tested successfully. For implementing the system, welding speed and the distance from the welding torch to the plates are important process parameters, which determine the weld size or the weld formation. In this research, the ranges of the welding speed are 70 ÷ 120 mm/min; 240 ÷ 460 mm/min; and 250 ÷ 450 mm/min for the SMAW, TIG, and MIG processes, respectively. These values were tested experimentally. The distance from the welding torch to the plates to display the weld joint is 1.5 ÷ 5 mm. Outside of this range, no weld joint is formed. The welding widths are 4.4 ÷ 12.9 mm, 7.1 ÷ 12.4 mm, and 7.4 ÷ 11.3 mm for the SMAW, TIG, and MIG processes, respectively. Full article

Quench and tempered (Q&T) steels are widely used for a diverse range of applications, particularly in the mining and defence industry, where wear and unconventional loading are common. Furthermore, they are particularly prone to hydrogen assisted cold cracking (HACC), imposing a more careful selection of consumables and requiring a comparably higher welder skill level to fabricate defect-free structures. Therefore, the cost of fabrication of welded structures is higher when the more preferred welding technique of shielded metal arc welding, SMAW, is employed. The introduction of the modified pulsed arc mode of depositions, a variation to pulsed arc deposition, has improved the productivity rates and can be utilised by welders with a greater skill variations. In this study, full-strength butt welds of Q&T steel (AS/NZS 3597 Grade 700), with the thickness of 20 mm, are fabricated under a high level of restraint using both conventional SMAW and modified pulse gas metal welding (GMAW-P). The study investigated the economic feasibility of the two deposition modes and the propensity to cracking for the welded joints under high restraint conditions. Utilising the modified GMAW-P resulted in 63% and 88% reduction in the ‘Arc-On’ time and the total normalised fabrication time, respectively. However, strict controls must be implemented, due to the increased propensity to lack of fusion-type defects, to optimise the welding procedure and mediate for such defects if GMAW-P is to provide a techno-economically beneficial alternative to conventional SMAW when welding Q&T steels. Full article