Advanced Welding Research Articles

Towards data-driven quality monitoring for advanced metal inert gas welding processes in body-in-white

In recent years, numerous monitoring approaches have been developed in the field of intelligent welding manufacturing to predict quality-related characteristics using process data and artificial intelligence-based techniques. While most investigations have focused on welding steel with conventional gas metal arc welding processes, the welding of aluminum and its alloys using advanced process variants has been less explored. This work addresses this gap by investigating data-driven methods for fault diagnosis and detection in an advanced metal inert gas welding process commonly used in body-in-white manufacturing. To this end, electrical, acoustic, and spectroscopic signals were recorded from numerous welding tests simulating typical fault causes. Various predictive models, ranging from traditional machine learning algorithms to state-of-the-art deep learning techniques, were trained and evaluated for classifying faulty seams and identifying their root causes. The results demonstrate that combining sensor data enhances the performance of predictive models compared to using individual sensors alone. However, a deep learning approach based solely on electrical signals emerged as the best solution for both use cases, considering both the results and practical aspects. Overall, the experiments highlight the significant potential of data-driven techniques to enhance quality monitoring in advanced MIG welding processes, promoting their more widespread adoption in body-in-white manufacturing.

Hybrid evolutionary algorithms (hybrid-GAPSO) based optimization of MIG welding process

MIG welding is a modern part of advanced welding process. In this article, the mathematical modeling by ANN and parametric optimization of MIG welding joining process of cast iron has been propounded using soft computing hybrid-GAPSO. The article also shows the best model using NN basis of fittest with experimental result, computational time, convergence speed and finally RMSE obtained from cross-validation. In this research, the optimal value of the input variables obtained by hybrid-HGAPSO so that output variables hardness (HA) will be maximum & surface roughness (SR) and width of breadth thickness (WOBT) will be minimum, has been illustrated. In this experimental analysis minimized RMSE of 1.15%, 1.433%, and 1.6678% for HA, WOBT and SR are accomplished respectively by HGAPSO-ANN.

Advanced welding automation: Intelligent systems for multipass welding in Butt Double V-Groove and Tee Double Bevel configurations

The paper addresses the imperative shift towards automation in welding processes, leveraging advanced technologies such as industrial robotic systems. Focusing on the reconstruction and classification of weld joints, it introduces a methodology for automatic trajectory determination. Utilizing a laser profilometer mounted on the robot, weld joints are reconstructed in three dimensions, and spurious data is filtered out through signal processing. A classification algorithm, integrating signal processing and artificial intelligence, accurately categorizes joint profiles, including V-joints and single bevel T-joints. The proposed intelligent and adaptive system enhances welding automation by analyzing point cloud data from laser scanning to optimize welding trajectories. This study establishes a foundational framework for further refinement and broader application in welding automation.Key Points•Introduction of a methodology for automated trajectory determination in welding processes.•Utilization of laser scanning and signal processing for reconstruction and classification of weld joints.•Implementation of an intelligent and adaptive system to optimize welding trajectories.

Innovative D-process MIG welding for enhanced performance of thick sections of MDN 250 in aerospace applications

Maraging steel, known for its exceptional strength, toughness and ductility, is widely used in aerospace and hypersonic missile manufacturing. The present study investigates the feasibility of joining 12 mm thick sections of maraging steel using advanced D-Process MIG welding technology. The D-Process integrates different welding modes such as MIG, Single Pulse-MIG and Double Pulse-MIG to optimize welding parameters, minimizing heat input. Additionally, the research investigates the influence of various post-weld heat treatments (PWHTs) on the performance of welded joints. The PWHTs included in the study are Ageing Treatment (AT), Solution Treatment + Ageing Treatment (SAT) and Homogenizing Treatment + Solution Treatment + Ageing Treatment (HSAT). Metallographic and mechanical tests were conducted on as-welded (AW) and PWHT conditions. Results showed the HSAT condition yielded superior properties with an average UTS of 1771 MPa, YS of 1734 MPa, and an average fracture toughness (FT) of 88 MPa√m. This underscores the efficacy of D-Process welding in meeting stringent requirements for maraging steel in aerospace and high-performance applications.

Investigations on corrosion rate, mechanical properties and structural homogeneity of interpulse TIG dissimilar weldments

This manuscript aims to investigate the welding characteristics, bead profile, structural integrity and corrosion behavior of low-carbon steel and Monel grade 400 dissimilar joints. The structures were developed using advanced welding technique, gas tungsten constricted arc welding, with Mo-based filler wire. Dissimilar metals after welding have been tested for internal inspection using X-ray radiography and confirmed to be free from all welding defects. Corrosion tests were carried out at various zones of weldment and characterized in a 3.5 wt% NaCl solution at 10 mV/s scan rate. The welding characteristics have been studied by conducting various tests including Vickers hardness, tensile and impact test. To reveal the structural integrity and perform chemical composition analysis of constricted arc weldment, OM/SEM techniques were used. Corrosion rate at steel interface is lower than that at the Monel 400 interface by 9.7% due to the less accumulation of heat. Uniform grain distribution and structural homogeneity were also observed along the weld zone due to constricted arc and controlled heat input.

Repairing weld for directly solidified Ni-based superalloy substrates using directed energy deposition of Inconel 625

Although the maintenance, repair, and operation of gas turbine systems are important issues in enhancing the operation of power units, advanced welding repair processes have limitations in depositing directionally solidified Ni-based superalloy components. To overcome this problem, in this study, a directed energy deposition method was applied to repair directionally solidified components using an Inconel 625 alloy. The rapid cooling rate and small laser beam diameter during directed energy deposition minimized the heat-affected zone and duration in the mushy zone, resulting in crack inhibition at the interface. The first laser scan partially melted the substrate and formed a mixing zone with a chemical composition gradient. By combining the chemical compositional gradient and dislocation accumulation due to repetitive solidification, that is, with the melting cycles of directed energy deposition, the thermal stability decreased, resulting in recrystallization and grain growth in the mixing zone. Consequently, the crack-free continuous interface of the partially repaired components did not induce tensile fracture near the interface. Although the mechanical properties of the IN625 deposit layer were degraded by severe heat treatment of the substrate, the results demonstrated that energy deposition with post-heat treatment is an effective approach in repairing Ni-based superalloy components without cracks and inclusion initiation.

Optimization of GMAW Processes in Robotic Welding: A Case Study from Automotive Manufacturing

The optimization of Gas Metal Arc Welding (GMAW) processes in robotic welding has become crucial for enhancing efficiency and quality in automotive manufacturing. This paper explores the integration of advanced robotic welding technologies, focusing on the use of the KUKA KR8 L8 Arc HW robot in GMAW applications. By leveraging artificial intelligence and sensor integration, this study demonstrates significant improvements in welding precision and process stability. Key advancements include the use of geometric and process sensors for real-time adaptive control, and the implementation of Fronius CMT for superior arc control and penetration. Detailed case studies from automotive manufacturing illustrate the practical benefits of these technologies, showcasing enhanced productivity, reduced cycle times, and improved weld quality. The findings underscore the importance of continuous innovation and optimization in robotic welding processes to meet the evolving demands of the automotive industry.

Experimental and numerical analysis of joints and thin-walled steel beams fabricated through resistance spot welding and hot-dip galvanizing

The study conducted a numerical and experimental analysis of lap joints and thin-walled beams made of DC01 steel. The beams consisted of webs formed by two flat bars, which were connected to flanges using cold-formed angles through advanced resistance spot welding (RSW) technology. The beams varied in geometry and mass. Load capacity evaluation was performed on the beams using a test stand consisting a testing machine and additional bending tooling. Prior to testing, some of the beams underwent hot-dip galvanization to create a bimetallic structure. The application of hot-dip galvanization resulted in the filling of free spaces between the welded sheets of the beams, leading to increased load-bearing capacity and stiffness in the galvanized beams compared to the non-galvanized ones. The galvanized beams tested during the experimental study exhibited a bending load capacity that was 59–83 % higher than that of the non-galvanized beams. The RSW lap joints were subjected to a uniaxial tensile test using digital image correlation and tracking (DIC). Three variants of joints were analyzed, differing in the number and arrangement of welds. The results obtained from the experimental tests were then compared with those from numerical analyses conducted in the ADINA software, utilizing the Finite Element Method (FEM). The initiation of cracks in the lap joints occured at the location of maximum plastic deformation, determined experimentally and confirmed by numerical simulations. The strength of the joint was influenced by the number and arrangement of welds in the joint. The use of 3D solid models to analyze RSW lap joints and resistance welded beams allowed for more accurate results in the weld area. The paper also presented the possibilities of using the designed beams.

Synchrotron diffraction residual stresses studies of electron beam welded high strength structural steels

In recent years, there's been a strong focus on enhancing high-strength structural steels (HSSSs), making them tougher, stronger, lighter, and more weldable. However, these steels face challenges like cold cracking sensitivity (CCS) and reduced toughness with higher heat input. Therefore, exploring HSSSs with advanced welding techniques like electron beam welding (EBW) is crucial. EBW known for its innovation and precision, is gaining popularity in HSSSs applications for vehicles, construction industries etc. offering advantages like narrow welds, reduced heat-affected zone (HAZ) and low distortion. It is essential to understand the influence of residual stresses (RS) in HSSSs which ultimately affect structural integrity and fatigue life. Using EBW on HSSSs, coupled with synchrotron XRD for residual stress studies, has great potential to advance this research significantly. In this work, a 15-mm-thick EB-welded joint of S960QL and S960 M steels was used to study the RS. At an energy level of 20 keV, RS data from the synchrotron XRD method and its result on the top of welded joints for both types of steel were compared. S960 M steel showed a longitudinal tensile stress of 250 MPa at the weld toe, approximately 1.8 times higher than the 138 MPa observed in S960QL steel under similar conditions. In transverse stress, S960QL exhibits a higher stress of 279 MPa compared to S960 M 46 MPa at the weld toe, approximately 83% lower. The synchrotron method measured 76% lower LRS for S960QL compared to conventional XRD, while S960 M exhibited 55% lower LRS using the same approach.

Investigation of Microstructure, Oxides, Cracks, and Mechanical Properties of Ti-4Al-2V Joints Prepared Using Underwater Wet Laser Welding.

Developing advanced underwater welding technology for titanium, which is the key structural material for underwater applications, is of great significance for the design, fabrication, and maintenance of submarine equipment. In this study, in order to investigate the underwater welding microstructure and mechanical properties of Ti-4Al-2V alloy, underwater wet laser welding was conducted on Ti-4Al-2V alloy using varying laser power. The microstructure and properties of the welding joints were characterized and analyzed. The microstructure of the heat-affected zone and fusion zone in the welding joints are not significantly different from those of welding in air, but a mixed oxide layer composed of Al2O3 and TiO2 is formed on the surface of the fusion zone. Due to internal stress, a large number of cracks initiate on the oxide layer and propagate to the joints. In the 4 kW and 5 kW joints, a penetrating crack formed due to the excessive accumulation of internal stress breaking up the α phase. The mechanical properties of the joints are significantly affected by the laser power. The tensile strength of the 3 kW and 4 kW joints is comparable to that of the base metal, which is about 600 MPa, while the 5 kW joint shows brittle fracture with no plastic deformation and 228 MPa strength. This research lays a solid foundation for understanding the underwater wet laser welding behavior of titanium alloys.

An innovative pulsed current arc welding technology for armor steel: Processes, microstructure, and mechanical properties

This study presents a novel pulsed current arc welding technology, specifically pulsed current gas tungsten arc welding (PC-GTAW), single and double pulse gas metal arc welding (SP/DP-GMAW), and dual process welding (D-process). This study aims to investigate the effectiveness of these welding techniques for armor steel weldments. This research focused on investigating the welding processes, resulting microstructures, and mechanical properties of welded joints. Based on the macrography analysis, it was determined that the weldments exhibit no signs of porosity, inclusions, or inadequate penetration. This finding substantiates the optimum settings for the weldment production process. The weldment optical microstructure, fusion, and heat-affected zone were examined in the weld interface. The microstructural properties of the FZ include δ-ferrite, austenite, bainite, and acicular martensite. The HAZ has a bainite-untempered martensite microstructure. The chemical composition and variations across the weldment (base, weld and HAZ) were identified. The grain borders contained greater quantities of Cr, Ni, Mn, Si, and Mo than those of the grain cores. EBSD revealed average weld zone grain sizes of 17.7 µm, 32.6 µm, 30.8 µm, and 24.6 µm for PC-GTAW, SP-GMAW, DP-GMAW, and D-Process, respectively.Furthermore, the hardness measurements showed a progressive transition across different regions. Additionally, the D-Process-fabricated material exhibited a maximum ultimate tensile strength of 872 MPa and an elongation of 4%. The mechanical properties exhibited by this new process variant exceed those of other weldments, indicating its potential for fabricating armor steel. The impact toughness demonstrated superior performance in all the weldments. Within this context, the new use of pulsed current advanced welding methods has shown the ability to generate welded parts of exceptional quality.

Research on the Causes and Treatment of Weld Zone Fracture in Cold Rolled High Strength Steel Rolling Process

In response to the poor quality of laser welding of cold-rolled advanced high-strength steel and the problem of easy fracture at the weld seam during the rolling process, the reasons for the fracture at the weld seam were first analysed using scanning electron microscopy and other equipment, to clarify the fracture characteristics and organizational distribution. Combined with the characterization results of mechanical properties, the reasons for the fracture at the weld seam during the rolling process were elucidated; Then, the influence of welding process on weld quality is studied from four aspects: laser power, welding speed, pre heat power, and post heat power; Based on the above analysis, a typical cold rolled advanced high-strength steel laser welding technology has been developed. By optimizing welding parameters such as welding power, speed, and preheating before and after, the quality of the weld seam and the cup protrusion effect have been ensured. At the same time, a reasonable rolling process optimization plan has been proposed; After applying the research results to the site, the quality of the weld seam has been significantly improved, and the occurrence rate of band breakage at the high-strength steel weld seam has decreased from an average of 3.6% per month to 0.13%. The band breakage defect at the weld seam has been effectively treated.

Effects of parameters on welding performance of the Ti/Al butt-joint in advanced plasma-MIG hybrid welding

Effects of parameters on welding performance of the Ti/Al butt-joint in advanced plasma-MIG hybrid welding

High-power fiber-coupled diode laser welding of 10-mm thick Inconel 617 superalloy

In the present study, a high beam quality fiber-coupled diode laser was effectively utilized to weld 10-mm thick Inconel 617 superalloy in single pass. Influence of critical parameters of focusing distance and welding speed on weld characteristics was systematically investigated and optimized. At optimum process conditions with the power density of ≈106 W/cm2, crack-free full-penetration weld with minimal distortion, porosity, and no underfill/undercut/root-hump defects were obtained with 97%–99% joint efficiency. The weld joint quality produced was on par with multipass employing conventional lasers and advanced laser-hybrid welding techniques and sufficient enough to apply in various applications of thermal power plants, ship building, and heavy industries.

Large-area joining of CF/Epoxy skin and Al alloy web by an advanced continuous resistance spot welding technology to manufacturing wind turbine blade

The large-area resistance welding of resin matrix composites and metal has always been a pursuit for manufacturing of hybrid structure. Herein, an advanced continuous resistance spot welding technology of CF/Epoxy composite and Al alloy based on multipoint sequential welding was developed, which was performed by a stainless-steel mesh implant at 0.4 MPa. A CF/Epoxy-Al alloy joint bonded was composed mainly by implant/resin and Al alloy/resin interfaces, shown a shear strength with about 17.9 MPa. Both types interfaces were analyzed and display similar results: C–O–metal bond formation at the interface is key reaction mechanism.

Study on relieving residual stress of friction stir welded joint of 2219 aluminum alloy using cold spraying

Friction stir welding is an advanced solid state welding technology, which has been widely used in aerospace and other fields. However, the large tensile residual stress developed in such joints will significantly affect mechanical properties. Cold spraying, as a new method to reduce residual stress of welded joints, can also improve the mechanical properties of the joints. In this paper, the correlation between microstructure and mechanical properties and residual stress of 2219 aluminum alloy joints prior and after coated with cold spraying was studied with experiments and numerical simulation for a 4 mm thick joint. The primary mechanism of stress relief of the joint was identified. Results show the refinement of grain size, with grain size decreasing from 2.1 μm in welded joints to 0.7 μm of cold sprayed joints, while high angle grain boundaries increase from 38.0% in the welded joint to 62.7% in cold sprayed ones. The ratio of recrystallized grains in the joints increases from 19.1% to 46.9%, while the joint strengthening phases θ″ and θ' increase, which increases tensile strength of the joints from 343 MPa to 398 MPa. The elongation is increased from 4.5% to 10.2%, and the average hardness of the joint is increased by 35 HV. The “ shot peening effect “ of cold spraying is found to be the primary factor to reduce residual stresses, while the “ heat flow effect “ has negligible effect on stress reduction. The mechanism of reducing residual stresses is provided by the macroscopic stress-strain theory and the microscopic dislocation theory.

Practice Design of Ship Thin Section Considering Prevention of Welding-Induced Buckling

_ The lightweight fabrication of thin-walled cabin sections is popular for advanced ships, and the dimensional tolerance generated by welding buckling significantly influences the fabrication accuracy and schedule with poststraightening. A typical thin section employed in the superstructure of a high-tech passenger ship is considered the research object. Conventional fabrication procedures and welding conditions were examined beforehand with combined thermal elastic-plastic and elastic FE computations based on the theory of welding inherent deformation, while welding buckling was represented with identical behavior compared with fabrication observation. Actually, there are usually two methods to prevent welding buckling with advanced fabrication. Stiffeners with optimized geometrical features and excellent elasticity moduli were assembled to enhance the rigidity of the ship thin section, and less welding inherent deformation with advanced welding methods can be employed to reduce mechanical loading. Computational results show that either less in-plane welding inherent strain or higher structural rigidity can reduce the magnitude of welding-induced buckling, and avoid the generation of welding-induced buckling during the lightweight fabrication. Keywords ship thin section; welding buckling; FE computation; welding driving force; structural rigidity

REVIEW OF ADVANCED WELDING AND TESTING FOR SAFETY IN OFFSHORE OIL AND GAS

The offshore oil and gas industry plays a crucial role in meeting global energy demands; however, it is fraught with inherent safety risks that necessitate constant welding and testing techniques advancements. This research paper reviews the significance of advanced welding and testing for safety in offshore oil and gas operations. This article explores traditional welding methods and their limitations in ensuring structural integrity and safety. It delves into a comprehensive analysis of advanced welding technologies, including friction stir welding, laser welding, and electron beam welding, highlighting their potential benefits in mitigating safety concerns. Moreover, the study examines the role of non-destructive testing (NDT) methods, such as ultrasonic testing, radiographic testing, and magnetic particle inspection, in evaluating weld quality and structural integrity. An emphasis is placed on integrating advanced welding techniques with NDT, demonstrating how this symbiotic relationship enhances safety and effectively identifies flaws and defects. Real-life case studies exemplify the practical implementation of these technologies in safeguarding offshore structures. The paper also addresses the challenges of adopting advanced welding and testing methods and envisions potential future developments in these technologies. Furthermore, it sheds light on existing regulatory frameworks and standards governing welding and testing in offshore operations, underscoring their role in ensuring safety and compliance.

Advancements in Welding Techniques: A Comprehensive Review

This study offers a comprehensive review of advancements in welding techniques and their impact on modern manufacturing. From historical evolution to emerging technologies like laser welding and friction stir welding, the study examines recent research, studies, and patents. Categorized advancements (process-related: 45%, equipment-related: 30%, material-related: 25%) collectively enhance welding quality, efficiency, and safety. Comparative analyses reveal reductions in welding time (20%) and heat-affected zones (15%), improved automation efficiency (25%), and enhanced joint strength (10%). Adoption trends show increasing use of laser welding (35%) in aerospace and friction stir welding (40%) in shipbuilding. Challenges include the lack of standardized guidelines (15% delay) and initial investment costs (10% slower adoption). Overall, this study underscores the transformative potential of advanced welding techniques, highlighting the need for sustained collaboration and innovation in modern manufacturing.

The influence of electron beam welding technology on mechanical properties of GH4169 welded joints

Super-alloy GH4169 and related welded structures were widely used in the aero-engine industry region. Vacuum electron beam welding is one of the most advanced welding technologies, and the influence of the mechanical property caused by the welding technology still needs further research. Firstly, the hardness, microstructure, and tensile properties of the GH4169 electron beam welded joint were tested. After electron beam welding and two-stage aging treatment, the weld zone was strengthened and its hardness is higher than that of the base metal zone. The microstructure characterization results showed that the grain size of the weld and heat-affected zone was larger than that of the base metal. The tensile results show that the static properties of the welded joint are similar to that of the base metal, and the residual height has no obvious effect on the static strength of the welded joint. The high-temperature creep properties of GH4169 electron beam welded joints with residual height were tested. The results show that residual height will lead to a transient fracture of welded joints under relatively safe service conditions. The fatigue performance of GH4169 welded joints with and without residual height was tested respectively. The results show that the fatigue life of the welded joints without residual height was about 10 times longer than that of the welded joints with residual height under the same stress level, and for the welded joint with residual height, the residual height position will become the main fatigue crack source.