The study provides a comprehensive analysis of the impact of welding parameters, specifically welding speed and the number of passes, on the residual stress distribution in AISI 304 (Z7CN18-09) austenitic stainless steel tubes. A three-dimensional finite element model (FEM) is developed in ABAQUS® to simulate the circumferential welding process. DFLUX and FILM subroutines are employed to represent double-ellipsoid moving heat source and thermal boundary conditions, respectively. Model validation is achieved by comparing simulated weld bead profiles and thermal cycles with experimental data, yielding excellent agreement (deviation < 5 %). The coupled thermal-mechanical analysis enables the evaluation of the spatiotemporal evolution of the temperature field at various welding speeds (80, 160, and 240 mm/min) and the distribution of axial and circumferential residual stresses across the tube thickness. The numerical results highlight the significant influence of welding parameters on the magnitude and distribution of residual stresses. Optimised welding speeds are shown to reduce maximum stress levels, while multi-pass welding improves stress homogenisation.

Acrylonitrile Butadiene Styrene (ABS) and Polystyrene Sheets (PS) are versatile thermoplastics that are likely to be used in engineering thermoplastics commonly employed in automotive interior components, consumer electronics housings, household and medical products, and lightweight packaging structures. ABS is durable and resistant to impact, while PS is stiff. The present study investigates the effect of different tool pin geometries and process parameters on the weld bead structure and mechanical properties of friction stir-welded (FSWed) dissimilar thermoplastics, ABS, and PS. Both tool pin profiles, namely Threaded cylindrical (TC) and threaded triangular (TT), were made with the same shoulder diameters (21 mm) and pin lengths (3.7 mm) and joint under varying process parameters, including traverse speeds (9, 18, 27 mm/min) and rotating speeds (800, 900, 1100 rpm) is used to join ABS & PS. With a maximum UTS of 24.5 MPa, Shore D hardness of 83.6, and elongation of 5% at 900 rpm and 18 mm/min, the TC tool continuously outperformed the TT tool. Because TT tools required less heat and churning, the weld appeared smoother but had lower mechanical strength (higher strength was found at 18.98 MPa at 900 rpm and 27 mm/min). The findings demonstrate that TC geometry offers better material flow and bonding, making it more suitable for thermoplastic joints with high strength.

Assurance of the integrity of every weld joint is highly desirable, and defect detection methods that can be applied to welds at high temperatures immediately after welding are required. The laser ultrasonic (LU) method, which generates ultrasonic waves in the target via pulsed laser irradiation, is a well-known technique for non-contact defect detection during welding. Ultrasonic waves excited in ablation mode exhibit large amplitudes and predominantly surface-normal propagation, which has driven extensive research into their application for weld inspection. However, owing to the size and weight of conventional equipment, such systems have largely been limited to bench-top experimental setups. To address this, we developed an LU robotic system incorporating a compact, lightweight laser source and an improved signal-processing system. We conducted experiments to measure signals and to detect backside slits in flat plates and blowholes in lap-fillet welds. Additionally, a method to improve the sensitivity of laser interferometers was investigated and demonstrated on smut-covered areas near weld beads.

A clean and sustainable environment is essential for all living beings, yet large-scale industrialization often compromises this balance. Boilers and pressure vessels, critical to many industries, produce significant waste and residues, raising serious environmental concerns. This study explores the development of submerged arc welding (SAW) flux by transforming industrial waste materials, specifically boiler fly ash and sugarcane bagasse ash, into a high-performance, cost-effective welding solution. The resulting flux not only reduces reliance on virgin mineral resources but also addresses waste management challenges. Comprehensive evaluations, including chemical composition analysis, mechanical property testing, and microstructural and fractographic analysis using FESEM, confirmed the flux’s adherence to ASME SFA 5.17 standards. Welds produced with the developed flux exhibited superior performance, with higher ultimate tensile strength (548.49 MPa) and impact toughness (133.33 J) compared to commercially available flux, alongside stable arc characteristics and a high-quality weld bead surface. Moreover, the developed flux offered a 64% cost savings over commercial alternatives, demonstrating both economic and environmental benefits. This research enhances welding efficiency and mechanical reliability while promoting sustainability through innovative waste repurposing.

Al-Zn alloys face difficulties during welding due to the development of secondary phases and solidification cracking. In molten pool solidification, the liquid films present at the boundaries of grains break apart within the mushy region, giving rise to a transitional semi-solid region. The TiC nanoparticles added to filler wire modify the welded material's microstructure, which acts as nucleate during welding. This paper uses TiC nano-treated filler to produce the weld-on-bead of AA7075 alloy through the cold metal transfer (CMT) welding process. To study the effect of input process parameters [i.e., wire feed rate (WFR), welding speed (WS), and gas flow rate (GFR)] on their responses (weld width, weld height, dilution %, and microhardness) were analyzed through response surface methodology (RSM). The central composite face-cantered design matrix was incorporated to assess the model's adequacy through variance analysis (ANOVA). The WFR is the most dominant parameter, followed by the WS and GFR for weld width, height, and microhardness responses. The heat input affects the microstructure of weld beads, and TiC nanoparticles prevent the dislocation and refine the grain size in the fusion zone. The microstructural and microhardness studies were conducted on the WAAM sample fabricated using the optimal input process parameters. The predicted optimal values of WFR, WS., and GFR are 8.5 m/min, 7 mm/s, and 19 L/min, respectively, which provide the maximum weld width of 8.21 mm, weld height of 3.59 mm, microhardness of 158.31 HV and minimum dilution of 33.90% of the weld bead. The microhardness of the bottom, middle, and top regions of WAAM using CMT have obtained 158 ± 2.43 HV, 152 ± 2.34 HV, and 147 ± 2.21 HV, respectively, which depend on the transfer of heat and heat accumulation in the material.

In recent decades, due to their great advantages, the aluminium alloys have been more and more used in the shipbuilding industry, particularly in the construction of yacht superstructures. Nevertheless, a significant disadvantage of aluminium alloys subjected to welding is their high deformation tendency, which represents an important drawback that needs additional remedial measures. In this study, a finite element analysis was performed, in order to investigate and optimize the design of welding paths used to carry out AA 5083 aluminium alloy T-joints of 6mm thick sheets by Metal Inert Gas (MIG) welding. The research methodology was focused on three case studies, in order to determine and comparatively analyse the Heat Affected Zone extend and the level of stress and displacement. In the first case, the welding beads were successively deposited, following the same welding direction. In the second case, the seams were successively welded, but the welding directions on one side and on the other side of the joint were opposite. In the third case, the seams were simultaneously welded, on both sides of the joint, the welding directions being opposite, as in the previous case study. Based on the research results, it was found that the larger Heat Affected Zone (HAZ) was identified in the third case study, while the total displacement was 25-30% lower, in comparison with the results obtained in the first two case studies. This phenomenon can be explained by the high amount of heat developed simultaneously by two electric arcs and transferred, by conduction, to the base materials. Due to the joining technology applied, that consisted in welding simultaneously on the both sides of the joint, an adequate balance of stress and strain was achieved, determining a lower total displacement.

This study investigates the combined influence of active fluxes (SiO2 and B4C) and ultrasonic assistance on TIG welding of Ti-6Al-4V, using A-TIG, U-TIG and U-A-TIG processes. Flux compositions were varied systematically, and three replicated weld beads per condition were characterized to ensure reproducibility. Geometric measurements, microstructural observations and spatially resolved microhardness profiles (0.5 mm step size, three indents per point) were reported as mean values together with observed experimental scatter. A-TIG welding significantly increased weld penetration, with the 50% B4C–50% SiO2 composition producing the highest penetration—approximately 21% greater than conventional TIG—owing to arc constriction and flux-induced oxygen activity. Ultrasonic assistance further modified molten-pool convection and cooling rates, promoting martensitic α′ formation and refined acicular α. TiB and TiC inclusions observed in flux-assisted welds contributed additional dispersion strengthening. Microhardness mapping showed that the U-A-TIG condition with 50% B4C–50% SiO2 achieved the highest hardness (≈423 HV), representing a 36% increase relative to the base metal (≈310 HV). Higher B4C fractions reduced pool fluidity and slightly decreased penetration and hardness. Within the controlled ultrasonic setup and flux-density constraints applied, the integrated microstructural and mechanical dataset provides a consistent basis for comparing flux–ultrasound interactions in α + β titanium welding.

Cr-Mn Austenitic Stainless Steel (ASS) are utilized in nuclear reprocessing plants, fast-breeder reactors, pressurised water reactors and boiling water reactors because of their ease of fabrication and welding. In this study two fillers were used, ER308L and ER308L-16, to weld ultra-low nickel Cr-Mn ASS using gas metal arc welding (GMAW) and shielded metal arc welding (SMAW) process. The simulation of the welding processes was carried out for the evaluation of stresses induced in the welding. The heat input is employed at the weld bead for modelling and analysis. From analysis, it was found that the weld bead width is less in GMAW as compared to SMAW. The transient thermal and structural analysis was carried out for evaluation of stresses in the weld using ANSYS. The weld for both welding methods was analysed using varying welding speeds. It was revealed that as the welding speed increases there is a decrease in Von-Mises stresses in the weld.

Role of Nitrogen in Shielding Gas on Slurry Erosion Performance of Duplex Steel Weld Beads Deposited on Nitrogen-Alloyed Austenitic Steel

Additive manufacturing (AM) offers significant potential but faces challenges in controlling rapid solidification processes due to thermal conditions. The application of magnetic fields provides a promising path to influence liquid metal behavior during solidification. Thermoelectromagnetic convection (TEMC) is one of the mechanisms by which an applied static magnetic field can induce melt flow, where thermal gradients at the solid–liquid interface generate thermoelectric currents, and in the presence of an external magnetic field induce Lorentz force that drives liquid convection, leading to enhanced heat transfer. This study investigates the impact of moderate static magnetic fields on the laser melting process of a Sn-10%wt.Pb alloy. It is found that applying a magnetic field significantly widens and deepens laser weld beads. Bead depth and width under different field strengths and orientations are measured. Numerical models are developed to calculate the TEMC current distribution and flow in the melt pool.

Objective: To compare MIG/MAG and LASER welding processes with automatic wire in the joining of SAE 1008-1010 low carbon steel sheets, evaluating mechanical performance, weld bead quality, heat-affected zone (HAZ), and operational feasibility. Theoretical Framework: The metallurgical industry is an essential pillar of the economy, and welding is one of its fundamental activities. In Brazil, the GMAW (MIG/MAG) process is widely dominant. However, technological advances, such as LASER welding, are being introduced to improve the quality, efficiency, and precision of conventional welding processes. Method: Experimental welding was performed on a bench in accordance with AWS B2.1/B2.1M:2021. The samples were prepared (ABNT NBR 13284) and subjected to tensile tests (ASTM E8/E8M-15ª), penetrant liquid inspection (ABNT NBR 16450), and metallographic analysis (ABNT NBR 15454). A comparative survey of consumable costs (wire, gas, and energy) was also conducted. Results and Discussion: LASER welding presented a smaller heat-affected zone, more precise surface finish, and mechanical performance similar to the MIG/MAG process. The LASER process resulted in a significant reduction of 34.62% in the final cost of consumables. However, there was a need for rigid alignment of the joints for LASER and a longer deposition time, attributed to the lack of specific operator training. Research Implications: The study concludes that the LASER process is technically feasible and capable of expanding its application in the metallurgical industry. The results provide technical and economic subsidies that can assist in decision-making for the adoption of LASER systems, recommending a payback analysis and operator training to optimize productivity. Originality/value: This work provides direct technical and financial validation, comparing an emerging method (LASER with automatic wire) to the dominant conventional process (MAG) in the metallurgical industry, focusing simultaneously on mechanical properties and cost feasibility.

Abstract This research aims to design and construct a self-made Positioner device for welding pipe work pieces using recycled materials, then welding them with a MAG process. The objective is to test suitable components for welding pipes approximately 100 millimetres in diameter and about 300 millimetres in length, with material thickness around 3.2 millimetres. The wire feed rate and welding current are fixed, with a CO2 gas flow rate of 8 litters per minute. The rotating device achieves a maximum speed of 4 revolutions per minute (100 Hz) and a minimum of 0.4 revolutions per minute (10 Hz) In experiments to find the appropriate Parameter, it was found that at a rotation speed of 0.8 revolutions per minute (20 Hz), the average weight of the weld bead is 19.4 grams, with an average welding speed of 55.98 seconds, bead height averaging 2.36 millimetres, and bead width averaging 6.75 millimetres. At 2 revolutions per minute (50 Hz), the average weight of the weld bead is 10.2 grams, with an average welding speed of 25.90 seconds, bead height averaging 2.38 millimetres, and bead width averaging 3.97 millimetres. Comparing the rotation speeds of both experiments with the arc lengths being the same results in the weld bead height being unchanged, but the average bead width differs by 2.78 millimetres, a difference of 41.19%. Additionally, there is a difference in the average weight of the weld bead by 9.2 grams, which amounts to a difference of 47.42% and a difference in average welding speed of 30.08 seconds, equating to a difference of 53.73%

Effect of process gas mixtures on weld material characteristics and bead geometry for wire-arc directed energy deposition

The influence of post-weld heat treatment on the corrosion resistance of CLAM steel weld bead in flowing LBE at 550°C

Overlapped weld bead analysis on dissimilar duplex stainless steel-2507 and inconel-625 using WAAM-CMT process

Modelling, analysis, and multi-objective optimization of single weld bead characteristics in wire arc additive manufacturing of Inconel 625 based on machine learning and NSGA-II

The aim of the research was to analyse the impact of peening each of the beads on the properties of a butt joint made of S960QL steel welded with ceramic backing on a robotic workstation using the 135 (MAG) method, and to determine the impact of pneumatic needle peening on the stress level. This analysis was based on a comparison of three butt joints: in the as-welded state, with each weld bead peened and post-weld heat treatment—stress relief annealing—performed. High-frequency peening (90 Hz) of each weld was performed to reduce stresses in the welded joint by introducing tensile stresses into it. A Weld Line 10 pneumatic hammer from PITEC GmBH was used for this purpose. The test joints obtained were tested in accordance with the requirements of EN ISO 15614-1. In order to determine the state of residual stresses, stress measurements were carried out using the Barkhausen effect based on the testing procedure of the technology supplier, NNT. This meter measures the intensity of the Barkhausen effect using a standard probe (with a single core). In order to verify the stress measurement using the Barkhausen method, stress measurements were performed using the XRD sin 2ψ technique based on the X’Pert Stress Plus program, which contains a database of material constants necessary for calculations. Structural studies, including phase analysis and crystallographic grain orientation, were performed using the backscattered electron diffraction method with a high-resolution scanning electron microscope and an EBSD (Electron Backscatter Diffraction) detector, as well as EDAX OIM analysis software. In addition, X-ray diffraction testing was performed on a Panalytical X’Pert PRO device using filtered cobalt anode tube radiation (λ = 1.79021 A). Qualitative X-ray phase analysis of the tested materials was performed in a Bragg–Brentano system using an Xcelerator strip detector. The tests showed that the high-frequency peening of each bead did not cause negative results in the required tests during qualification of the S960QL plate-welding technology compared to the test plates in the as-welded and post-stress-relief heat treatment states. Interpass peening of the weld face and HAZ resulted in a reduction in residual stresses after welding at a distance of 15 mm from the joint axis compared to the stress measurement result for the sample in the as-welded condition. This allows for a positive assessment of peening in terms of reducing the crack initiator in the form of the concentration of tensile stresses in the area of the fusion line and HAZ.

ABSTRACT Similar and dissimilar aluminium alloys joining in fusion welding lead to common weld defects such as hot tears, distortion, porosity, and solidifying cracks in the weld bead. These issues can be rectified by joining the materials in their solid state using friction stir welding. Defect-free joints can be obtained by monitoring the joining surface during welding. This research article describes the real-time monitoring of friction stir welding of similar (AA6061-T6/AA6061-T6) and dissimilar (AA5083/AA6061-T6) aluminium alloys using the acoustic emission technique. A similar and dissimilar aluminium alloy joint was fabricated under conditions such as without defects, pinhole defects, and piping defects, and its mechanical and metallurgical characteristics were assessed. A maximum joint strength of about 282 MPa and 266 MPa was obtained in similar and dissimilar joints fabricated without defects. The superior hardness observed at the stir zone of both similar and dissimilar joints was about 108 HV and 75 HV in the without defect condition. A scanning electron microscope (SEM) was used to analyse fractured areas of tensile samples. A recorded Acoustic emission (AE) signal pattern during at the time of Friction Stir Welding (FSW) was used to study AE parameters such as counts, amplitude, RMS, and Hits.

Abstract In this study, dissimilar butt welding of 0.8 mm thick DP600 and 1 mm thick DP1180 advanced high-strength steels was performed using fiber laser beam welding with beam oscillation. The effects of oscillation type (linear and circular), oscillation amplitude (0.5, 1, 1.5 mm), and welding speed (50–80 mm s −1 ) on weld bead geometry, microhardness, and tensile load were investigated. A total of 12 experimental sets were conducted by keeping the laser power and frequency constant at 1.2 kW and 100 Hz, respectively. Metallographic evaluations, Vickers microhardness tests, and tensile tests were carried out in accordance with standard procedures. The results revealed that welding speed had a significant influence on weld penetration and width, with optimal parameters determined as 60 mm s −1 speed and 1 mm amplitude in both oscillation types. Circular oscillation generally led to higher microhardness values, whereas linear oscillation produced wider weld seams. While amplitude increase decreased penetration depth, it improved weld width. The tensile load of all joints was largely influenced by the DP600 base metal, where fractures were consistently observed. However, the joint at 1.5 mm amplitude in circular mode fractured in the weld zone, indicating insufficient penetration. The findings suggest that proper selection of oscillation parameters can enhance weld quality and mechanical performance when joining dissimilar high-strength steels for lightweight automotive applications.

ABSTRACT Aluminium alloys are metallic materials composed primarily of aluminium, combined with elements such as copper, magnesium, manganese, silicon, tin, nickel, and zinc to enhance specific properties like strength, corrosion resistance and machinability. Metal transfer plays a vital role in determining the stability of the arc, weld productivity, weld bead appearance and quality in Gas Metal Arc Welding (GMAW) process. This research offers an in-depth examination of AA6061 aluminium alloy weldments created using ER5356 filler wire through the constant current, pulsed current, cold metal transfer and pulsed cold metal transfer (PCMT-GMAW) techniques. This study presents the comparative evaluation of metal transfer modes on mechanical, microstructural and corrosion characteristics of GMA welded AA6061 aluminium alloy joints. Mechanical tests including tensile and hardness assessments revealed increased strength and hardness in the PCMT-GMAW weldments compared to the other modes. Potentiodynamic corrosion tests demonstrated that the PCMT-GMAW weldments had recorded higher corrosion potential (Ecorr) and lower current density (Icorr) values compared to the other modes. The results revealed that PCMT-GMAW mode imparted superior mechanical properties and corrosion resistance characteristics compared with the other modes owing to the low thermal gradient triggered by the joint influence of arcing and short-circuiting phase with pulsing.