Welding Parameters Research Articles

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.

ANALYSIS OF FRICTION STIR WELDING JOINTS ON HIGH DENSITY POLYETHYLENE (HDPE) DUE TO CHANGE IN MATERIAL TEMPERATURE AND SPINDLE ROTATION

Friction stir welding (FSW) can be a solution in solving the problem of joining thermoplastic polymers which are difficult to do with fusion welding. Selection of the proper FSW connection parameters can produce optimal connection quality in HDPE material joints. In friction stir welding, the heat of welding is used to raise the temperature of the material from its initial state to the solid state temperature. If the material temperature (T0) is increased above room temperature (TRoom), while the FSW welding parameter is constant, then at a certain increase in T0 it will produce excess welding heat which results in excessive softening or even melting of the material being welded. Therefore, the material temperature setting (T0) becomes an important parameter FSW The process of connecting the HDPE plates with friction stir welding was carried out by varying the material temperature (T0 ) of TRoom, 50 0C, 75 0C and 100 0C. While the spindle rotation varies 2000 rpm and 2500 rpm. Other parameters controlled include the type of square butt joint, 5 mm HDPE plate thickness, 20 mm/min feed rate, 0.1 mm plunge depth, 20 mm tool shoulder diameter, 4.5 mm pin length and 6 mm pin diameter. The result is that the higher the spindle rotation and the material temperature during the welding process causes the FSW peak welding temperature to increase. The highest peak weld temperature was obtained at variations in material temperature (T0) 100 °C with a spindle rotation of 2500 rpm, which is 123.2 °C or 94% of the melting temperature of HDPE. The hardness of the weld nugged area is still lower than the hardness of the base material. The highest average tensile strength of the research variations was achieved at a spindle rotation speed of 2500 rpm and a material temperature of 75 °C of 16.8 MPa, higher than the average tensile strength of the base material which is 15.1 MPa.

Investigation of Microstructure and Mechanical Properties of Al Alloys Lap Joints by Friction Stir Welding

An experimental investigation on effect of friction stir lap welding (FSLW) process parameters on mechanical and microstructure of AA6082-O welds is presented. Three process parameters namely tool rotational speed (1000,1400 & 2000 rpm), tool shoulder diameter (18, 20 & 22 mm) and tool traverse speed (28, 56 & 80 mm/min) are considered. Experiments are planned as per L9 Taguchi array. Data are analyzed in terms of S/N ratio and Analysis of Variance (ANOVA). Tensile shear strength is observed in the range of 11.79 MPa to 29.23 MPa. It is observed that tool diameter and tool rotational speed are most significant factors affecting tensile shear strength. Optimum levels of process parameters (28 mm/min tool traverse speed, 18 mm tool diameter and 1400 rpm tool rotational speed) is decided based on analysis of experimental data. Using optimum process parameters for friction stir lap welding of Al alloys improved quality of welded joints can be made. Use of optimized parameters will improve the performance of the products in terms of durability and load carrying capacity.

Thermal and residual stress analysis of multi-pass welded stainless steel pipes using DEFLUX and FILM subroutine

This study presents an in-depth investigation of the influence of welding parameters (welding speed and number of passes) on the residual stress distribution in AISI 304 (Z7CN18-09) austenitic stainless-steel tubes. A three-dimensional finite element modeling (FEM), developed in ABAQUS, was implemented to simulate the circumferential welding process. The DFLUX and FILM subroutines were implemented to model the double ellipsoid mobile heat source and thermal boundary conditions, respectively. Model validation was performed by comparing weld bead profiles and thermal cycles with experimental results, showing excellent correlation (deviation < 5%). The coupled thermal and mechanical analyses allowed evaluation of the spatiotemporal evolution of the temperature field for different welding speeds (80-160-240 mm/min) and the distribution of axial and circumferential residual stresses as a function of tube thickness. The numerical results demonstrate a significant influence of these parameters on the amplitude and distribution of residual stresses, with a notable reduction in maximum stresses for optimized welding speeds and better stress homogenization with multi-pass welding.

Refill Friction Stir Spot Welding of an Al-Li Alloy: The Effects of Rotating Speed and Welding Time on Joint Microstructure and Mechanical Properties

In this work, 2060 Al-Li alloy was joined by refill friction stir spot welding (RFSSW). The effects of the tool’s rotating speed and welding time on the microstructure and mechanical properties of the welded joints were studied. The results showed that joints without defects can be obtained within a wide range of welding parameters. Tiny voids were formed when using a low rotating speed of 1600 rpm, and incomplete refilling was obtained when using a short welding time of 1 s. Increasing the rotating speed from 1600 to 2000 rpm increased the grain size of the stir zone (SZ). When using a short welding time of 1 s, the grains of the SZ were not completely broken with high orientation differences in the grains. Higher hardness was obtained in the SZ when using a lower rotating speed and shorter welding time. Increasing the rotating speed increased the joint strength, while short and long welding times decreased the joint strength.

Improving Deposition Quality of Stellite Powder on Valve Seats by Optimized TIG Welding Parameters

The quality of the Stellite powder coated on these valve seats depends on the discharge profile and is crucial to the service length and quality of these seats, especially when called upon to work at their maximum capabilities. This research seeks to work out how to minimize blow holes in the TIG welding process when depositing Stellite powder while maintaining other desirable qualities of the weld. In this respect, the work uses the OVAT technique and Taguchi design approach to analyze the effect of the major welding parameters, such as weld speed, feed rate and welding current, on the formation of blow holes. The research shows that it is possible to gain a remarkable increase in weld quality when the parameters mentioned are strictly controlled. In this systematic experimentation, the optimal welding condition found out was the welding speed of 6.5 rpm, feed rate of 120 mm/min, and welding current of 150A. With this combination, these parameters were determined to reduce the chances of blow-holes forming and increase the welds' quality and durability. With respect to the study objectives, the present investigation offers a clear direction to enhance TIG welding of valve seats with special reference to minimize the defects. Analysis done in the study shows that the welding parameters have the greatest impact in reducing the blow holes; the feed rate is 56.61%, weld speed is 22.28% and welding current is 20.17%. The results enhance weld quality, offering rules for eradicating imperfections in the TIG welding of valve seats, which is crucial for high-performance sectors.

Effects of multi-objective optimization of friction stir welding process parameter on mechanical and ballistic properties of AA5754 aluminum alloy

Friction stir welding (FSW) is a solid-state welding process commonly used to join similar and dissimilar aluminum alloys. This study aims to investigate multi-criteria decision-making, multi-objective optimization, Taguchi’s L9 design of experiments, and the technique for order preference by similarity to the ideal solution (TOPSIS) to evaluate the effects of various FSW parameters specifically, welding speed, feed, and axial load on the mechanical properties of AA5754 aluminum alloy. Following the enhancement of the welding parameters, an analysis of variance (ANOVA) was performed to identify the most influential parameter in the FSW process. The findings indicated that tensile strength, impact strength, and microhardness were predominantly affected by welding speed (94.82%), feed (3.12%), and axial load (1.32%), respectively. With a hexagonal tool and optimal process parameters of feed (20 mm/min), axial load (7 kN), and speed (1200 rpm), the joint obtained the maximum microhardness (81 HV), impact strength (3.01 J/mm2), and tensile strength (163.89 MPa). The microstructure and X-ray diffraction analyses indicated that the crystals were tiny, with higher dislocations in the stir zone, indicating improved mechanical properties. In the FSW joint, dimples and voids were observed on the tensile and impact fracture surfaces. Finally, the ballistic properties of the optimized AA5754 FSW joint were determined. An asymmetric V-shaped deformation profile was observed around the impact point, with the highest deformation at the center. An increase in impact velocity from 134 to 187.6 m/s did not result in significant differences in the deformation of the FSW joint. The fracture surfaces of ballistic-tested friction stir welded joints exhibited shear regions and localized bands.

Effect of heat input on microstructural evolution and impact toughness in dissimilar weld metals between medium Mn and V-microalloyed steel

High-quality weld metals are a prerequisite for ensuring the integrity of dissimilar steel welded joints. This research investigates the influence of heat input on the inclusion characteristics, variant selection, crystallographic texture, and resultant impact toughness of dissimilar weld metals used in joining heavy-plate medium Mn steel (MMS) and V-microalloyed steel (VMS). Results revealed that inclusion density decreased but its size increased as heat input increased from 10 to 15 and 20 kJ/cm, which alters in the nucleation mechanism of acicular ferrite (AF) from intragranular nucleation to sympathetic nucleation. The percentage of AF initially rose from 81.3 % to 83.2 %, and then declined to 79.1 %. Variant selection also transitioned from random to specific due to the variation in transition temperature and nucleation mechanism. Meanwhile, the fraction of unfavourable crystallographic texture increased from 1.5 % to 22.9 % and 26.1 %. Impact toughness was higher (128 J) at 10 kJ/cm compared to 15 kJ/cm (108 J) and 20 kJ/cm (110 J) owing to its smaller inclusion size and a lower percentage of unfavourable crystallographic texture. These findings offered theoretical guidance for selecting welding parameters in industrial applications for dissimilar welded joints of MMS and VMS.

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

Impact of tool geometry and friction stir welding parameters on AZ31 magnesium alloy weldment wear behaviour and process optimization

This study investigates the impact of friction-stir welding (FSW) tool pin shape (TPS) and processing variables, viz., rotation speed (RS), axial load (AL), and traverse speed (TS), on weld beads’ wear characteristics as per ASTM G99 standard. Wear rate (WR), friction force (FF), and coefficient of friction (CoF) are analyzed based on Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). FSW performed with a hexagonal TPS provides a better material flow between the plates, influencing the joint’s strength and improving the wear resistance of weldments. Higher RS leads to high material flashing, providing lower strength and wear properties. Changes in TPS from triangle to pentagon and from pentagon to hexagon produced higher tensile strength, at 11.16% and 12.15%, respectively. The Chimp Optimization Algorithm (ChOA) shows an optimal condition of hexagon TPS, AL of 2 kN, RS of 1800 rpm, and TS of 25 mm/min, whereas TOPSIS optimal condition are hexagon TPS, AL of 4 kN, RS of 1400 rpm, and TS of 50 mm/min. Confirmation experiments with optimal conditions shows, ChOA producing lower WR, CoF, and FF by 12.5, 2.56, and 1.54% than TOPSIS. Compared with TOPSIS, ChOA produced lower WR, CoF, and FF by 12.5%, 2.56%, and 1.54%.

Real‐Time Observation of Strain Evolution in Lap Shear Test of BH220 Steel Resistance Spot‐Welded Joints via a Digital Image Correlation Method

This article presents an investigation of the real‐time deformation and strain field changes of baked hardening (BH) 220 steel plate resistance spot welds in the lap tensile shear tests via digital image correlation (DIC) technology. 2D DIC analysis can be used to provide a quantitative assessment of the strain competition between the weld nugget and the surrounding metal. The data obtained from the DIC technique indicate that the shear strain is primarily concentrated in the outer metal of the weld, consistent with a nugget pull‐out failure (PF) mode. In contrast, if the welding parameters are inappropriate, for example, if the welding current is 7.2 kA, the welding time is 10 cycles and the electrode pressure is 0.35 MPa, a significant shear strain appears in the nugget of the BH220 weld. This subsequently causes the weld to fail in an unfavorable interface failure mode in the shear test. Calculations show that if the failure mode is nugget pull‐out, the mean failure strength is 13.5 kN, while the value for interface failure is 6.55 kN. The PF mode is characterized by ductile failure, whereby the material yields and necks through the base material. This failure mode is not associated with the notch region.

Microstructure Evolution and Cryogenic Impact Toughness Changes in Ce‐Containing Novel Cryogenic High‐Mn Austenitic Steel Weld Metals under Different Heat Inputs

The Ce‐containing novel cryogenic high‐Mn austenitic steel weld metals under different heat inputs are prepared by submerged‐arc welding to provide a satisfactory welding parameter scheme and further optimize its cryogenic impact toughness. The effect of heat input on microstructure, inclusion, and cryogenic impact toughness of weld metals are investigated via optical, scanning electron microscopy, electron backscatter diffraction, electronic probe microanalyzer, and cryogenic impact test. The results show that the dendrite arm spacing, segregation ratio of Mn, Si, and C elements and average effective grain size of the weld metals gradually increase, and the proportion of high‐angle grain boundaries decrease with the heat input increase from 11.91 to 20.24 kJ cm−1. The type of inclusions of weld metal with different heat inputs are all Ce2O3 and Ce2O2S. The number density of inclusions decreases monotonically from 5976 to 4912 mm−2, while the average size increases from 0.32 to 0.45 μm with the heat input increased. The increase in heat inputs consistently decreases the mean cryogenic impact toughness of weld metals from 123 to 102 J. The higher proportion of high‐angle grain boundaries and finer inclusions at lower heat input play the critical role in improving the cryogenic impact toughness.

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.

Evaluation of Structural Transition Joints Cu-Al-AlMg3 Used in Galvanizer Hangers

The paper deals with the evaluation of the quality of Cu-Al-AlMg3 structural transition joints (STJ) made by explosion welding proposed for the renovation of galvanizer hangers. The three-layer joint consisted of electrolytic copper with a thickness of 25 mm, 2 mm of aluminium represented by the AW1050 alloy, and 25 mm of the EN AW 575 aluminium alloy. Light microscopy analysis confirmed the wavy pattern of both interfaces of the welded joint and significant plastic deformation in close proximity to the waves. Microhardness measurement revealed a partial strain hardening of the AW5754 copper-aluminium alloy near the interface and a significant increase in microhardness in the vortex zone of waves, reaching a value of up to 863 HV 0.025. Microcracks were also observed in these places. The intermetallic phase Al2Cu was identified in the vortex zones by XRD analysis. As a continuous layer of intermetallic phase was not observed in the interface of the welded joint, it is possible to consider the used welding parameters as appropriate. A semi-quantitative EDX analysis revealed a diversity of chemical composition in the vortex zones, which does not correspond to the phase composition based on the equilibrium binary Al-Cu diagram due to non-equilibrium conditions in the formation of the welded joint interface. The bond strength of three-layer welded joint evaluated by the strength test ranged from 151 to 171 MPa, which represented approximately a two-fold increase in comparison to the ultimate tensile strength of alloy AW1050, while the failure occurred in all samples at the AW1050-AW5754 alloy interface.

Parameters influence on mechanical properties of resistance spot welding: AISI304L/AISI1005

AbstractWelding dissimilar metals by resistance spot welding offers several advantages, including lighter weight and better mechanical properties for the shipping, aerospace, and automotive industries. The resistance spot welding parameters effects (welding current, squeeze time, welding time, and hold time) on the welding results of AISI 1005 and AISI 304L were investigated in the present research. The joints' tensile shear force, microhardness, and microstructure were examined. The Taguchi design of experiments approach was utilized to analyze the tensile shear force results statistically. A welding current of 7 kA, welding time of 1.4 s, squeeze time of 1.2 s, and hold time of 0.8 s resulted in an optimum tensile shear force of 6.194 kN. Additionally, the nugget zone demonstrated a higher hardness compared to the base metal and heat-affected zones.

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.

Effect of Process Parameters on the Mechanical Properties of Simultaneous Double-Sided Friction Stir Welding Joints

Currently, conventional single-sided friction stir welding is primarily suitable for joining thin plate aluminum alloys, and its application to thick plates is still challenging in terms of welding efficiency and joint mechanical properties. Simultaneous double-sided friction stir welding (SDS-FSW) is a high-efficiency joining technique specifically developed for welding thick plates. However, there is little research on the influence of SDS-FSW process parameters on the joint mechanical properties. In this study, a 12 mm thick AA6061-T6 aluminum alloy and dual robot welding equipment are used to conduct SDS-FSW experiments exploring the influence of rotational speed ω\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\omega$$\\end{document} and welding speed v on the mechanical properties and microstructure. The results show that when the welding parameters are ω\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\omega$$\\end{document} = 800 r/min and v = 60–80 mm/min, smooth and defect-free thick plate aluminum alloy SDS-FSW joints can be obtained, and the macroscopic morphology of the joints is distributed in a “dumbbell” shape. The grain size in the weld nugget zone increases with increasing welding heat input. The microhardness distribution in the joint displays a “W” shape, and the hardness value of the weld nugget zone can reach 67% to 86% of that of the base metal (BM). The junction between the thermo-mechanically affected zone and the heat affected zone is the weakest region of the joint, with the lowest hardness being approximately 51% of that of the BM. When the welding parameters are ω\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\omega$$\\end{document} = 800 r/min and v = 140 mm/min, the SDS-FSW joint has the highest tensile strength, reaching 78.43% of the BM strength and exhibiting ductile fracture characteristics. This research indicates that acceptable weld strength in thick aluminum alloys can be achieved via the SDS-FSW joining mechanism, highlighting its significant potential for industrial applications.

Tribological performance enhancement of AISI 1050 steel through FeNiCrCoMo high-entropy alloy TIG weld cladding

The tribological behavior of tungsten inert gas (TIG) welded high entropy alloy (HEA) FeNiCrCoMo cladding deposited on AISI 1050 steel substrate was studied. The response surface methodology (RSM) optimized the TIG welding parameters. The SEM images revealed no signs of intermetallic compounds in the cladding, and the XRD analysis showed that the FeNiCrCoMo greatest peak corresponds to the BCC+FCC mixed phase. The microhardness and sliding wear resistance of the cladding were superior compared to the steel substrate owing to the solid solution strengthening and the presence of mixed phase. The worn surfaces of HEA claddings showed the presence of wear debris, grooves and micro-cutting from sliding wear as revealed by the SEM and 3-D profilometry images.