Optimum Welding Parameters Research Articles

Multi-Objective Welding Optimization for AA5052 Using Taguchi-Fuzzy Approach

<div>This study investigates the influence of tungsten inert gas (TIG) welding parameters on the dilution and hardness of AA5052 aluminum alloy. Employing Taguchi’s L27 orthogonal array, the research systematically explores the effects of current, voltage, and welding speed. Analysis of the experimental data utilizes signal-to-noise ratio, analysis of variance (ANOVA), and regression techniques. The study compares a traditional regression model with a fuzzy logic approach for result validation, finding that the latter exhibits marginally better predictive accuracy. Optimal welding parameters are identified as 150 A current, 20 V voltage, and 45 mm/s welding speed, yielding a maximum dilution of 52.81% and hardness of 145.3 HV 0.5. Current emerges as the most significant factor influencing both dilution and hardness. Microstructural examination, hardness profiling, and tensile testing of specimens welded under optimized conditions reveal a characteristic hardness distribution across the weld zones and ductile fracture behavior.</div>

TIG Welding of EN AW-6082 Al Alloy: A Comparative Analysis of Filler Rods on Microstructural and Mechanical Performance

This study investigates the impact of different filler wires (ER5356, ER4043, and ER4047) on the microstructural and mechanical properties of EN AW-6082 Al alloy joints produced by tungsten inert gas (TIG) welding. Butt-welded samples with a single V-groove joint configuration were prepared using optimized welding parameters. The welded samples were subjected to visual inspection, microstructural analysis, hardness testing, tensile testing, and impact toughness evaluation. The results showed that all the welds were free of visible defects. Microstructural examination revealed that the ER5356 filler produced the finest grain structure of 18.03 ± 3 μm, while ER4047 resulted in the coarsest grains of 36.07 ± 5 μm. Correspondingly, the joints made with ER5356 exhibited the highest tensile stress of 278 ± 6 MPa, yield stress of 219 ± 5.4 MPa, hardness values of 72.7 ± 5 HV, and welding efficiency of 86.07%, whereas those made with ER4047 produced the lowest values. The hardness in the weld region was lower than that in the parent metal and heat-affected zone for all samples. However, ER4047 welds demonstrated superior impact toughness and strain-hardening capacity. The findings underscore the importance of filler metal selection in tailoring mechanical properties for high-performance applications.

Optimization of fatigue life of the seismic vibrator baseplate considering the coupling effect of welding residual stress

The seismic vibrator baseplate (SVB) is a welded structure. Ignoring welding residual stress (WRS) and only considering cyclic stress can decrease the accuracy of fatigue life assessments. This study aims to investigate the fatigue life prediction and optimization of SVB under the influence of WRS. A welding model of SVB and an SVB-ground excitation model were developed, and the stress distribution of SVB was determined using the finite element method. A fatigue life prediction study that incorporates WRS, based on a modified S-N curve, was conducted. A multi-objective fatigue life optimization analysis was performed using genetic algorithms. The results shows that the backing weld (BW) of the SVB is the most susceptible area to fatigue failure. Under the combined effects of WRS and working stress, the fatigue life of the SVB is 8.14 years. When considering WRS, the prediction results align well with field data, showing an error margin of less than 5 %. WRS is identified as a critical factor influencing the fatigue life of SVB, and optimizing welding parameters can effectively reduce WRS, thus extending the service life. The optimal welding parameters were found to be welding interpass temperature of 105 °C and welding speed of 10.23 mm/s. After optimization, the fatigue life of the SVB increased to 10.23 years, a 25.68 % improvement over the pre-optimization condition. Previous studies did not consider the influence of WRS, whereas this work integrates it into the fatigue analysis, producing a modified S-N curve that enhances the accuracy of life prediction. Furthermore, multi-objective optimization algorithms and fusion decision-making methods were applied to the fatigue life optimization of the SVB, offering novel research approaches and methodologies. This study provides theoretical guidance for the structural design and optimization of the SVB, aligning with practical engineering needs and showing substantial application value.

Residual Stress Characteristics in Spot Weld Joints of High-Strength Steel: Influence of Welding Parameters

This study examines the residual stress characteristics of spot welding in newly developed high-strength steel for automotive body construction through experimental and numerical methods. The effects of sheet thickness, nugget size, and the presence or absence of spacers on residual stress distribution and fracture stability were evaluated. Measurements using XRD and HDR revealed tensile residual stress below the yield strength at the nugget center. A numerical analysis system corroborated experimental findings, demonstrating that larger nugget sizes reduce tensile residual stress at the nugget center, enhancing fracture stability. However, for nugget sizes of 3 (t: thickness), high tensile stress at the nugget edge compromised stability, while sizes of 3.5 or larger improved fracture resistance. The study also found that thicker sheets increased fracture safety with larger nugget sizes, and the presence of spacers induced tensile stress through spring-back effects, which shifted to compressive stress as the nugget size increased. These results provide critical insights into optimizing welding parameters to improve the structural integrity of automotive components.

Vibration Welding of PLA/PHBV Blend Composites with Nanocrystalline Cellulose.

Thermoplastic composites have garnered significant attention in various industries due to their exceptional properties, such as recyclability and ease of molding. In particular, biocomposites, which combine biopolymers with natural fibers, represent a promising alternative to petroleum-based materials, offering biodegradability and reduced environmental impact. However, there is limited knowledge regarding the efficacy of joining PLA/PHBV-based biocomposites modified with nanocrystalline cellulose (NCC) using vibration welding, which restricts their potential applications. This study demonstrates that vibration welding enables efficient bonding of PLA/PHBV composites with NCC, resulting in strong, biodegradable, and environmentally friendly materials. The investigation revealed that the addition of nanocrystalline cellulose (NCC) at 5, 10, and 15 wt.% significantly enhanced the strength of welded joints, with the highest strength achieved at 15% NCC content. Microstructural analysis using scanning electron microscopy (SEM) and deformation studies with digital image correlation (DIC) indicated that a higher NCC content led to greater local deformation, reducing the risk of brittle fracture. Mechanical hysteresis tests confirmed the composites' favorable resistance to variable loads, highlighting their stability and energy dissipation capabilities. Optimization of welding parameters, such as vibration amplitude, welding time, and pressure, is crucial for achieving optimal mechanical performance. These findings suggest that PLA/PHBV composites modified with NCC can be utilized as durable and eco-friendly materials in various industries, including automotive and packaging. This research presents new opportunities for the development of biodegradable high-strength materials that can serve as alternatives to traditional plastics.

ENHANCING WELDING QUALITY THROUGH PREDICTIVE MODELLING — INSIGHTS FROM MACHINE LEARNING TECHNIQUES

In this work, the application of various machine learning (ML) algorithms for predicting tensile strength based on welding parameters in AA2014-T6 aluminium alloy joints is studied. Six ML models namely linear regression, AdaBoost regression, random forest regression, support vector regression (SVR), multi-layer perceptron regression and gaussian process regression (GPR) are considered. The comprehensive analysis revealed that SVR exhibited superior generalization capabilities on unseen data, achieving an R² of 0.89 and a low RMSE of 15.64. In contrast, GPR, despite its high training accuracy, showed significant overfitting. This work highlights the potential of ML in optimizing welding parameters and highlights the importance of model selection and tuning to prevent overfitting and ensure reliable predictions.

Investigating the effects of ultrasonic assistance on TIG welding of AA7075 alloys: a machine learning-based optimization study using RSM-PSO

Abstract This study explores the impact of ultrasonic assistance on TIG welding of AA7075 alloys, leveraging a machine learning-based optimization approach combining Response Surface Methodology (RSM) and Particle Swarm Optimization (PSO). A central composite design matrix was developed to investigate the effects of process parameters on microhardness and weld defects. A predictive model was constructed, utilizing process parameters as inputs and microhardness as the output. PSO optimization was then applied, followed by experimental validation. The model demonstrated high accuracy, with R-squared values of 0.9808 and 0.9862 for conventional and ultrasonic-assisted TIG welding. Confirmation tests showed an error margin of less than 1%. The optimal process parameters under ultrasonic vibration were identified as welding current (50.38 A), gas flow rate (12.42 l min−1), and filler material (ER5356). The predicted microhardness (153.16 HV) closely matched the actual value (150.71 HV), with an error of 1.6%. Tensile and fractography analyses further validated the optimized welding parameters. This research showcases the potential of integrating ultrasonic vibration with RSM-PSO optimization to enhance weld quality and mechanical properties of AA7075 alloy joints, offering valuable insights for industrial applications.

A Study of the Performance of Dissimilar Pulsed-Laser-Welded JSC590R/JAC980YL Steel Joints of Differential Thickness

To reveal the correlation between the mechanical properties of JSC590R/JSC980YL steel pulse-laser-welded joints and welding parameters, this study adopts the response surface analysis test method to determine the welding parameters, and examined the macroscopic morphology, microstructure, microhardness, and tensile properties of the cross-section of the welded joints. The results revealed that the key factors influencing welded joints quality, in descending order of importance, are distance to focus, welding speed, and single-pass heat input. The interaction between these factors is extremely significant. The weld zone of the joints is primarily composed of lath martensite, while the heat-affected zone is composed of ferrite, martensite, carburite, tempered martensite, and residual austenite. The optimized welding parameters align with actual expectations, yielding an average engineering stress of 616.9 MPa for the joint. Notably, the fracture area shifts from the heat-affected zone of JSC590R to the base material.

Hybrid Entropy–Principal Component Analysis–Combined Compromise Solution Techniques for Optimizing Welding Parameters of Monel 400 and Validation via Machine Learning

Hybrid Entropy–Principal Component Analysis–Combined Compromise Solution Techniques for Optimizing Welding Parameters of Monel 400 and Validation via Machine Learning

Optimizing 3D Laser Foil Printing Parameters for AA 6061: Numerical and Experimental Analysis

Abstract This study utilizes a technology known as 3D laser foil printing (LFP) to create precise structures by layering metal foils using laser welding. Metal foils have the advantages of rapid cooling and efficient heat conduction, allowing for the formation of fine-grained structures. However, when dealing with materials like aluminum alloys in laser processes, defects can arise as a result of their high reflectivity. To address this challenge, laser circular oscillation welding (LCOW) is applied to the LFP process. LCOW's circular motions with higher scanning frequencies widen the keyholes and reduce some defects such as spattering, bubble formation, and microcracks. Simulation predictions with an error margin of approximately 10% in comparison to experimental results demonstrate the reliability of the model. Furthermore, the study integrates circular packing design with artificial neural networks to create comprehensive processing maps tailored to different criteria for extracting optimal welding parameters. As a result, for the optimized processing parameters screened using the above systematic process, no cracks were observed on the upper surface of the 3D LFP parts produced with a laser power of 800 W and a scanning speed of 550 mm/s, and only 0.12% porosity was observed from the cross section of the sample. Future research will focus on incorporating simulation results to model microstructures more precisely and continually refining LCOW parameters as new materials and technologies emerge, ensuring the ongoing enhancement of weld quality in the 3D LFP process.

Application of gray relational analysis for optimizing stud welding parameters of IF 7114 steel for the automotive industry

In this study, the application of stud welding to IF 7114 steel sheets in the automotive industry using stainless steel and copper-plated steel studs with different diameters and welding voltages was investigated. The aim is to optimize welding parameters and investigate their effects on the mechanical properties of the weld zone. Taguchi optimization and gray relational analysis were used to identify the best welding parameters for tensile strength and torque resistance. Results showed that the highest tensile strength and torque resistance were achieved with a stainless steel M8 stud diameter and 150 V welding voltage, while the lowest values were observed with copper-plated steel M5 studs and 180 V voltage. Additionally, stainless steel studs consistently outperformed copper-plated steel in both tensile strength and torque resistance. The study concludes that stainless steel studs, particularly with an M8 diameter at 180 V, offer the most favorable welding performance.

A multi-scale modeling framework for solidification cracking during welding

A multi-scale multi-physics modeling framework has been developed to predict solidification cracking susceptibility (SCS) during welding. The framework integrates a thermo-mechanical finite element model to simulate temperature and strain rate profiles during welding, a cellular automata model to simulate the solidified microstructure in the weld pool, and a granular model to calculate the pressure drop in the mushy zone. Verification was achieved by comparing the model’s predictions with welding experiments on two steels, demonstrating its capability to accurately capture the effects of process parameters, grain refinement, and alloy composition on SCS. Results indicate that increasing welding velocity, while maintaining a constant power-to-velocity ratio, extends the size of the mushy zone and increases the maximum pressure drop in the mushy zone, leading to higher SCS. Grain refinement decreases separation velocities and the permeability of liquid channels, which increases SCS, but it also raises the coalescence temperature, resulting in an overall reduction in SCS. Alloy composition impacts SCS through thermal diffusivity and segregation. Lower thermal diffusivity or stronger segregation tends to elongate the mushy zone, resulting in an increase in SCS. This framework provides a robust tool for understanding the mechanisms of solidification cracking, optimizing welding parameters to prevent its occurrence, and comparing SCS of different compositions during alloy design.

Taguchi, Grey Relational Analysis, and ANOVA Optimization of TIG Welding Parameters to Maximize Mechanical Performance of Al-6061 T6 Alloy

This study presents a comprehensive investigation into optimizing Tungsten Inert Gas (TIG) welding parameters to enhance the mechanical performance of the widely used Al-6061 T6 alloy, specifically in a double V joint configuration with a plate thickness of 6 mm, for aerospace applications. The Taguchi method was employed to design the experiments, providing a robust framework for analyzing the influence of the electrical current, voltage, and gas flow rate on weld quality. Additionally, a Grey Relational Analysis (GRA) and an Analysis of Variance (ANOVA) were used to validate the optimal welding parameters and quantify the significance of each factor. The optimized parameters were determined to be an amperage of 180 A, a voltage of 18 V, and a gas flow rate of 10 L/min, resulting in significant improvements of up to 40% in tensile strength and 23% in hardness, demonstrating the effectiveness of the optimized conditions. The findings provide valuable insights into welding metallurgy, offering practical guidelines for enhancing high-performance welded joints in critical industrial applications. This study underscores the potential of combining Taguchi, GRA, and ANOVA methodologies to achieve superior mechanical properties and reliability in welded structures.

Optimization of bobbin tool friction stir welding parameters of AZ31 magnesium alloy based on FEM and its influence mechanism on mechanical properties

Based on the 3D transient heat transfer theory, the finite element model of bobbin tool friction stir welding (BT-FSW) of AZ31 magnesium alloy sheet is established. The effects of different process parameters on the quality of BT-FSW joint of magnesium alloy were discussed using temperature distribution, mechanical properties, fracture morphology analysis, and EDS element distribution analysis. The results show that in the process of BT-FSW, the cross-section temperature of the plate is symmetrically distributed in an hourglass shape, the AS is slightly lower than that of RS, and the transverse temperature is distributed in an ‘M’ shape. When the rotating speed is 700 rpm and the welding speed is 180 mm/min, the weld surface is smooth, and its ultimate tensile strength can reach 81.82% of the base metal strength. The tensile specimen is quasi-cleavage fracture. When the heat input is insufficient, there are a lot of Al8Mn5 Precipitated phases in the TMAZ fracture zone, which increases the fracture brittleness of the joint. When the heat input is enough, the precipitated phase dissolves evenly, the river-like fracture surface of the joint retains the dimple characteristics, and the mechanical properties are improved.

Analysis and Optimization of Laser Beam Welding Parameters for Aluminium Composite (Al-Zn-Cu Alloy) by Grey Relational Optimization

Aluminium and its composites are widely used in production to enhance the strength of lightweight objects. In this study, an AA7075/SiC composite was fabricated using a stir casting route. Multi-objective optimization and finite element analysis were performed with various process parameters on a manufactured aluminium composite (AA7075 + SiC) undergoing a laser beam welding process. Four welding parameters, i.e., pulse frequency, power, welding speed (transverse), and wire size were taken for laser welding as per the L-9 orthogonal array for experimental study. Tensile strength, deflection, temperature distribution, Rockwell hardness (fusion zone), and Rockwell hardness (heat affected zone) were taken as output parameters after welding. The standard deviation objective weighting–grey relational optimization method optimized the process parameter. ANSYS APDL 23 software was utilized to simulate the entire laser welding method with a cylindrical heat source to predict the temperature distribution in the butt-welded plates. This software uses finite element analysis and gives a deviation of only 5.85% for temperature distribution with experimental results. This study helps to understand the effect of various parameters on the welding strength of the aluminium composite.

Research on the Cavitation Resistance Testing of Friction Stir Welded Joint of En Aw 1200 Aluminium Alloy

Aluminium alloys are being used more often as a result of industry demands for strong, lightweight materials. Because of its advantages over conventional fusion welding techniques, friction stir welding, or FSW, has become a promising technique for joining aluminium alloys. Nonetheless, there is still cause for concern regarding FSW joints' vulnerability to cavitation erosion, which is a major issue in applications exposed to harsh environments. The cavitation resistance of EN AW 1200 aluminium alloy joints made by the FSW process is the main objective of this study. By utilizing specialized equipment to conduct cavitation tests, the study uses a comprehensive methodology to assess the cavitation erosion behaviour of these joints. A number of variables are investigated in order to determine how they affect the cavitation resistance of the welded joints, including mechanical attributes, welding parameters, and microstructural features. The goal of the study is to shed light on how well FSW joints function and hold up in cavitation scenarios. This information will be useful in improving the dependability and suitability of EN AW 1200 aluminium alloy in sectors where the ability to withstand cavitation erosion is critical. The findings from this study are expected to contribute to the optimization of welding parameters and material selection, ultimately advancing the use of aluminium alloys in critical applications requiring resistance to cavitation-induced damage.

Ultrasonic Welding Parameter Optimization for Electric Component Welding

Industrial requirements to establish metallic joints between dissimilar metals in the electric area. The ultrasonic welding process is an optimal process to joint thin sheets or foils. The goal of the research was to optimize the ultrasonic welding parameters to join thin nickel-coated copper sheets and aluminium sheets. It used a 0.5 mm thick high-purity copper (Cu-OF-R200) sheet coated with a 10 μm pure nickel layer and a 0.5 mm thick aluminium (1050A H24) sheet. The ultrasonic welding is made by a Branson Ultraweld L20 ultrasonic welder equipment. The mechanical properties and exacting geometrical tolerance of the joint were required. The welding parameter optimization is made empirically, with several welding tests. The optimal welding parameters were confirmed by non-destructive and destructive tests of the joints. The non-destructive tests were the visual inspection and geometrical measurements of the joint sizes. The destructive tests were tensile tests and macroscopic and microscopic tests. The completed test results confirmed the process applicability and the quality of the joint.

Physical Heat Cycle Measurement of Resistance Spot Welding

Resistance spot welding (RSW) is still the ideal joining method in the automotive industry. Mostly steel sheets are used in the car body, so overlap and layering are required for welding or riveting, as spot welding provides simultaneous clamping force with interfacial welding to ensure the required strength and quality. A fundamental understanding of heating and cooling rates in thermal distributions is essential for predicting microstructure formation in the weld and the heat-affected zones (HAZ) of RSW joints. The ability to measure the heat cycle in the RSW process can be valuable in weld control and welding parameter optimization. RSW parameters can be optimized through tensile shear tests and microscopic investigations. Heat cycle measurement (HCM) demonstrates the welding consequences in terms of the change in mechanical properties and microstructural formations. The accuracy of cooling rate measurements including t8/5 cooling time is very important to predict the microstructural evolution in the HAZ, however, the thermocouple measurement raises numerous challenges due to the high temperature gradient and small weld and HAZ size. During our investigations heat cycle measurement has been conducted experimentally by a K-type thermocouple. The data logger is connected to the output of the thermocouple for recording the voltage to measure the temperature distributions as a function of both time and position during the welding process. Measurement results of 1 mm thick martensitic MS1400 steel overlapped RSW joints are discussed, and the HCM curve of heating and cooling rates of the spot-welding process is presented. The heat cycle during RSW was measured with two different welding parameter combinations. In addition to welding current, welding time, and electrode force, pulsation has shown disparate curves. Numerous experiments have been attempted to measure the heat cycle in HAZ sub-zones due to the difficulty of positioning the thermocouple accurately, uppercritical HAZ, intercritical HAZ, and subcritical HAZ were investigated and measured in both welding parameter combinations. Difficulties were encountered in the experimental work as a result of the instantaneous welding time and the vibration resulting from the passage of alternating electrical current between the two electrodes. A magnetic field is generated that affects the thermocouple measurement and appears as a noisy curve that is filtered out and smoothed. Joule heat, interfacial heat generation, and cooling effects of electrodes are also considered in the experiment.

Study of the effect of SMAW welding speed on the microstructure and crystal stability of X70 steel using X-ray diffraction

This study investigates the impact of manual electric arc welding (SMAW) speed on the microstructure of X70 steel. Welding was performed at two distinct speeds: S1 = 20 mm/min and S2 = 35 mm/min, at the COSIDER BISKRA workshop in Algeria. X-ray diffraction (XRD) analysis was conducted on the welded zones to examine crystal orientation, size, dislocation density, and structural stability across different welding areas, including the base metal (MB), heat-affected zones (HAZ1 and HAZ2), and weld zones (WZ1 and WZ2). The XRD results revealed that key crystal peaks, such as {110} and {200}, retained their positions at both welding speeds, though variations in {110} peak intensity were noted. The lower welding speed (S1) resulted in a higher heat input, which enhanced crystal stability, increased crystal size, and reduced dislocation density. On the other hand, the higher speed (S2) produced lower heat input, leading to smaller crystal sizes, increased residual stresses, and a greater number of defects due to rapid cooling. These findings underscore the critical influence of welding speed on heat input, cooling rates, and their consequent effects on microstructure. The study highlights the importance of optimizing welding parameters to balance microstructural integrity, mechanical performance, and production efficiency.

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.