Shoulder Diameter Research Articles

An enhancement of the yield strength and hardness in the friction stir welding of AZ31/AA3105 joint

The objective of this research is to optimize the yield strength and hardness of AZ31/AA3105 joint during the single pass friction stir welding (FSW). For this purpose, Taguchi method was used to examine the influence of FSW parameters such as rotating speed, linear speed, advancing side and shoulder diameter on the hardness and yield strength of the welding. The microstructure of the joint has also been analyzed by optical and scanning electron microscopy (SEM) to evaluate the joint quality. The results of microstructure analysis indicated that a high quality joint with thin intermetallic layers obtained at rotating speed of 1100 rpm and linear speed of 30 mm/min. The optimization results indicated that the hardness (78.06 HV) and yield strength (129.2 MPa) can be improved simultaneously with the advancing side of Mg, rotating speed of 1100 rpm, linear speed of 30 mm/min, and shoulder diameter of 15 mm. The fracture surface of samples indicated that a combination of brittle and ductile fracture was occurred at rotating speed of 1100 rpm and linear speed of 30 mm/min, which improved the ductility and toughness. It was concluded from the obtained results that a high-quality joint with improved mechanical properties can be obtained between AZ31 and AA3105 alloys in the optimal conditions of FSW parameters.

Friction stir welding of AA2024-T3 and SS304 alloys: microstructural analysis, microhardness evaluation, and tensile performance

This study examines the feasibility of friction stir welding (FSW) for dissimilar butt joints formed between 3 mm thick 2024-T3 aluminum alloy and AISI 304 stainless steel. It explores the impact of operational parameters, particularly traverse speeds of 20 and 40 mm min−1, a fixed tool rotation speed of 450 rpm, a tool pin offset of 1.5 mm, and a tool shoulder diameter of 18 mm, on microstructure, microhardness, and tensile strength. A traverse speed of 40 mm min−1 resulted in a lower peak temperature of 257.75 °C, while optimal conditions at a speed of 20 mm min−1 led to peak temperatures of 356.5 °C. This higher temperature facilitated material deformation, improved flow, enhanced mixing, and contributed to grain refinement, with an average grain size of 4.2 μm. Vickers microhardness tests revealed a maximum hardness of 339 Hv at a traverse speed of 40 mm min−1 and 413 Hv at 20 mm min−1. The ultimate tensile strength (UTS) reached 338 MPa, resulting in a joint efficiency (JE %) of 76.81% for the weld performed at optimal conditions.

Anthropometric parameters as risk factors for dilated cardiomyopathy in carriers of rs1805124 and rs35068180 polymorphisms

Aim. To identify anthropometric parameters that are associated with a more frequent development of dilated cardiomyopathy (DCM) in patients with rs1805124 and rs35068180 polymorphisms.Material and methods. The present study included 111 patients with idiopathic dilated cardiomyopathy (DCM) (99 men (89,2%) and 12 women (10,8%)). The mean age of the participants was 51±9,1 years, with an age range of 20 to 69 years. The control group included 101 healthy individuals (mean age, 50,8±12,3 years; age range, 34 to 79 years (men, 86,1%)).The Rees-Eysenck index (body length*100/chest transverse diameter*6) and the Tanner's sexual dimorphism index (3*shoulder diameter–intercrestal diameter) were used.In addition to the conventional body mass index (BMI), the study determined waist circumference, hip circumference, body shape index (BSI), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), body adiposity index (BAI), body roundness index (BRI).Results. Patients carrying the GG genotype had significantly higher WHR, BAI, and BRI indices compared to the control group. However, similar differences were also observed among carriers of the AG and AA genotypes. Also, carriers of the AG and AA genotypes of the rs1805124 polymorphism significantly differed from the control group in WHR and WHtR. This may indicate the primary influence of somatometric indices, rather than the studied polymorphisms, on the DCM development.The multivariate analysis performed using the Wald stepwise selection method showed a significant effect of BRI (p=0,000) and the Rees-Eysenck index (p=0,000) on the development of DCM in carriers of the rs1805124 polymorphism GG genotype. In patients carrying the 6a/6a genotype, the WHtR, WHR, BMI, BAI, and BRI were significantly higher than in the control group. Similar differences were also observed among carriers of the 6a/5a genotype. The indices of WhtR, BAI, BMI, and BRI were significantly higher in carriers of the 5a/5a genotype. However, similar differences were also observed among carriers of the AG and AA genotypes. Also, carriers of the AG and AA genotypes of the rs1805124 polymorphism significantly differed from the control group in both WHR and WHtR.Conclusion. Most likely, such somatometric indices as BRI, WHR, WHtR, BAI, and BMI are of great importance in the development of DCM. In carriers of the homozygous rare allele G of the rs1805124 polymorphism, independent predictors of DCM may be BRI and the Rees-Eysenck index, while in carriers of the rare allele 5a of the rs35068180 polymorphism — BRI, BMI, and the Rees-Eysenck index. However, BRI and the Rees-Eysenck index may be independent predictors of DCM regardless of the genotypes of the studied polymorphisms.

Microscale channels produced by micro friction stir channeling (μFSC)

The current literature lacks comprehensive research on the processing limits of the Friction Stir Channeling process (FSC) for creating the smallest continuous and integral channels, using tools with threaded probes 2 mm in diameter or smaller. This study pioneers the exploration of the extreme limits of the microscale FSC process, with potential applications in the development of ultra-compact heat exchangers, seeking to enhance the efficiency and sustainability of these systems. Customized tools were designed and manufactured, with predefined dimensions and geometries to establish a set of parameters that consistently produce continuous microchannels, maximizing the hydraulic diameter within the constraints of each tool's specifications and geometry. Comprehensive evaluations—including continuity, watertightness, micro-computed tomography, neutron computed tomography, microhardness testing, and thermal measurements—were conducted to ensure the channels' structural integrity and suitability for super-compact heating and cooling applications. Internal channels were successfully created using tools with threaded probes measuring 2.0, 1.0, and 0.5 mm in diameter, and corresponding shoulder diameters of 5, 4, and 3.5 mm, within 5 mm thick AW1050-H111 aluminum alloy plates. The smallest channel achieved a hydraulic diameter of 191 μm, using a 0.5 mm diameter threaded probe, thus qualifying it as a microchannel. The thermal performance of a compact heat exchanger model was also tested, demonstrating that despite the high cost associated with tool production, particularly due to the specialized manufacturing processes required, the FSC process remains viable, reliable, and repeatable for the production of mini- and micro-channels.

Load Capacity and Bending Strength of Double-Acting Friction Stir Welded AA6061 Hollow Panels

Aluminum alloy hollow panels are essential components in both civil and mechanical structures, such as building floors or large vehicle platforms. They enhance rigidity while staying lightweight and conserving material volume. In its application, this panel must be joined using welding methods. One common issue encountered in aluminum welding is the formation of porosity defects. Solid-state welding methods like Friction Stir Welding (FSW) can be a solution to address this problem. The FSW joining process on hollow panels cannot be completed in one welding operation due to their thickness. The FSW process must be performed on both surfaces, which requires a relatively long time. Therefore, FSW needs to be developed into a Double-acting FSW that utilizes two tools simultaneously. These two tools introduce two sources of heat input, pressing force, and friction-stirring, resulting in a novel response that needs further research. This study delves into the impact of welding speed variations in Double-Acting FSW on the load capacity and bending strength of AA 6061 hollow panel joints. Welding speeds of 20, 30, and 40 mm/min were tested alongside rotational speed (1500 rpm), tilt angle (2°), and shoulder diameter (24 mm). It was discovered that reducing welding speed enhances both load capacity and bending strength. Notably, specimens welded at 20 mm/min exhibited a load capacity of 15.61 kN and bending strength of 52 MPa, highlighting the potential of slower speeds for superior weld performance. Doi: 10.28991/CEJ-2024-010-08-018 Full Text: PDF

Multi-weld Quality Optimization of Friction Stir Welding for Aluminium Flange Using the Grey-based Taguchi Method

Friction stir welding (FSW) is gaining traction as a preferred technique due to its potential to reduce heat input and enhance the mechanical properties of welded joints. However, the path to commercializing FSW for flange joints is not without challenges. Two primary obstacles are the complexity of the welding path and the intricate design requirements for the fixtures. These factors contribute to the difficulty in determining the ideal weld settings and process parameters, which are critical for achieving optimal results. The current study addresses these challenges by applying FSW to flange joints using custom-engineered fixtures. These fixtures are meticulously designed to hold the pipes and plates securely during the welding process. The focus of the research is on optimizing the multi-performance characteristics of FSW for Al 6063 flange joints through the hybrid Grey-based Taguchi method. The integrity of the weld joint is assessed by examining various mechanical properties within the weld zone, including rotation speed, travel speed, tool profile, and shoulder diameter. The study identifies the optimal parameter settings for the FSW process: a rotation speed of 3000 rpm, a travel speed of 3 mm/min2, a shoulder diameter of 20 mm, and a conical tool profile. Under these ideal conditions, the welded material exhibited a tensile strength of 170.169 MPa, a hardness of 63.7709 HV, and a corrosion rate of 0.022 mm/year. These findings underscore the effectiveness of the optimized FSW process in producing robust and durable flange joints.

Analysis of variance and grey relational analysis application methods for the selection and optimization problem in 6061-T6 flange friction stir welding process parameters

A study was carried out to investigate and enhance the effects of friction stir welding on the mechanical characteristics of a flange composed of 6061-T3 aluminum alloy. The pipes possess an outer diameter and wall thickness of 6 mm, while the plates are sized at 100 x 100 × 6 mm. Nine unique experiments were planned using the Taguchi orthogonal array method, with the welding tool remaining constant. Three independent variables (travel speed, rotation speed, and shoulder diameter) were altered at three different levels for each variable. The research analyzed the influence of various FSW factors on the weld flange joint. Analysis of variance (ANOVA) and grey relational analysis (GRA) were employed to determine the impact of each FSW underwater parameter. Moreover, the statistical Taguchi technique (TM) was used to predict the optimal combination of welding parameters to improve tensile properties, including tensile strength (UTS), yield strength (YS), elongation (EI%), and bending load (BL) of welded joints. Additionally, the actual tests demonstrated a high level of agreement with the results obtained from the proposed mathematical model. The validation results obtained indicate that the optimization method is a dependable tool for enhancing the quality responses of friction stir welding.

Effect of tool rotational speeds on material flow and strain rates during friction stir butt welding of AA2219-T87 plates

ABSTRACT Friction stir welding (FSW) process is widely used for joining Al-Cu alloy (AA2219-T87) plates because of its high joint efficiency and low residual stresses in contrast to fusion-based joining techniques. A two-way coupled, 3D thermal-material flow model has been developed in COMSOL software, and the effect of tool rotational speeds on thermal and material flow fields, strain rates, thermal histories, and size of weld zones are being studied. The non-uniform net heat generation during the FSW process is due to the friction between workpiece and tool materials and the deformation energy of plasticized material flow sheared by the rotating tool. An approximate range of temperatures for the weld zones has been proposed and found to be appropriate because the predicted sizes are in good agreement with the experiments. Furthermore, the authors suggested that a quality FSW joint must have the nugget zone smaller and the heat-affected zone larger than the tool shoulder diameter.

Effect of shoulder diameter, tool rotation speed, and arrangement of plates on mechanical and metallurgical properties of dissimilar aluminum 2024-T3 and 7075-T6 friction stir spot welding (FSSW)

In most studies conducted on friction stir spot welding, the focus has been on process parameters and the tool pin geometry. One of the influential parameters in this process, which has received less attention, is the tool shoulder diameter. The spread or concentration of the weld can significantly affect the weld strength and mechanical properties of the joint. In this research, two tools made of H13 hot-work steel with different shoulder diameters of 20 and 25 mm were prepared. Three rotation speeds of 1000, 1600, and 2400 rpm were considered for the welding process. The arrangement of aluminum plates on top of each other was varied in two configurations, parallel and overlapped. Mechanical properties, including tensile shear strength and Vickers micro-hardness, were investigated. The microstructure of different weld zones was also examined using an optical microscope. The results showed that increasing the tool shoulder diameter could enhance the breaking force and tensile shear strength of the joints. Meanwhile, the rotation speed had an optimal value, and with its increase, the breaking force initially increased and then decreased. Placing the 2024-T3 aluminum plate on top of the stack also increased the tensile shear strength of the samples. The fracture mode of the broken specimens was entirely nugget pull-out, which became more pronounced during the use of optimal parameters. Micro-hardness in the region influenced by heat decreased, reaching a minimum in the thermo-mechanically affected zone. In the stir zone, micro-hardness increased significantly due to intense plastic deformation and material compression. The microstructure in the nugget region appeared fine-grained and compact, while the region affected by coarse grain experienced significant heat effects. Increasing the tool shoulder diameter led to an increase in the nugget zone and the length of the bonded region. However, it did not have a significant effect on grain size in the nugget region.

The Influence of Multi-Pass Friction Stir Processing on the Microstructure Evolution and Mechanical Properties of IS2062 Steel

The motive of present work is to explore the variation in the material characteristics of steel upon multi-pass friction stir processing. Steel plates (IS2062) that were 3 mm thick, were subjected to friction stir processing in a multi-pass manner. The selected transverse speed was 150 mm/min, along with a tool rotation of 800 RPM when using a tungsten carbide tool (shoulder diameter—10 mm). Steel plates were processed using the single-pass, double-pass, and triple-pass travel of the rotating tool to observe the impact of multi-pass processing on the properties of steel plates. Multi-pass friction stir processing resulted in a higher micro-hardness of 175 VHN after the second pass, in comparison to the unprocessed metal, which had a micro-hardness of 130 VHN, owing to the collective effect of the plastic flow of the material due to the rotation of the tool and frictional heat, which also leads to grain refinement. The second pass evidenced an average grain size of 22 microns, whereas the unprocessed material had an average grain size of 57 microns. The results of EBSD and SEM characterization showed reasonably improved material properties of the processed work materials.

Evaluating the Microhardness Profiles in Friction Stir Welding of Dissimilar Alloys

Abstract: Friction stir Welding (FSW) advancement is used generally in the utilization of present-day flying and vehicle industry for predominant fundamental mentioning. Such a joining technique is displayed to avoid serious twists and the made excess weights are exhibited as low when it is stood out from the traditional welding structure. In this research, focus on to identify the parameters that will provide the dissimiliar alloys of aluminium AA6061 and AA8011 with good microhardness properties. From the current study microhardness strength of dissimiliar alloys of aluminium varies with the rpm, feed rate and shoulder diameter of the tool. At 2000 rpm and 15mm/min welding speed strength of joints is low and at high rpm 2400 and welding speed 20mm/min micro hardness strength is always low but at a rotation speed of 2200 rpm and welding speed 20 mm/min maximum strength of the weld joint . Hence at high rotational speed rise in the temperature occurs and cause dissolution of precipitates which lowers the hardness and at low rotational speed less heat generation at the tool workpiece interface causing less refinement of grains which lower the hardness value. During tensile strength test fracture and cracks occurs at weld center line.

Optimizing Micro Friction Stir Spot Welding (mFSSW) of Aluminum Alloy AA1100 Using Neural Network Model

This study explores the optimization of Micro Friction Stir Spot Welding (mFSSW) by investigating the influence of tool profiles on welding outcomes, using aluminum alloy AA1100 with a 0.42 mm thickness as the specimen material. Monitoring temperature and RPM during welding with thermocouples and tachometers, mechanical properties are assessed through tensile shear tests, microhardness measurements, and macrostructural observations. The findings serve as the basis for developing Neural Network models using Rapidminer software, marking a transformative development that positions Neural Networks as potent tools for optimizing welding processes, potentially leading to achieving optimal weld quality. The investigation also delves into three welding tool configurations – the two-stage pin, one-stage pin, and pinless mFSSW probes – highlighting their distinct impacts on tensile shear test values and overall welding quality. Notably, the two-stage pin configuration emphasizes the significance of larger pin diameters and controlled heat generation for enhanced weld strength, while the one-stage pin configuration underscores the pivotal role of pin diameter and elevated temperatures in improving weld quality. The pinless mFSSW probe configuration, on the other hand, emphasizes the importance of shoulder diameter and temperature control for superior tensile shear test results. Leveraging Neural Network modeling for optimization, this study advances our understanding of parameter interactions and underscores the efficacy of Neural Networks in achieving superior tensile shear test values and welding quality in mFSSW, offering valuable insights for future endeavors in the field..

Process parameters settings of friction stir welding using multi-response optimization for aluminum alloys

The defense and aerospace industries utilize the AA2050, an aluminum-lithium alloy of the third generation. Principal component analysis (PCA) and Taguchi-grey relational analysis (GRA) are utilized in this study to enhance the process constraints for friction stir welding (FSW). The quality of the weld can be influenced by various process factors such as the speed at which the weld is traversed, the speed at which the tool is rotated, the angle at which the tool is tilted, the diameter of the shoulder, and the shape of the tool pin. The combination of PCA and the well-known Taguchi-GRA approach enables the objective estimation of response weights. Here, a Taguchi L16 orthogonal array was designed, and sixteen tests were carried out using it. These experiments were conducted with various assessments including tensile strength, yield strength, elongation percentage, hardness of the weld zone, bending load, etc Through the utilization of Taguchi-GRA-PCA analysis, the most suitable process parameters were identified as a traverse speed (TS) of 160 mm min−1, a rotating speed (RS) of 900 rpm, a tilt angle (TA) of 2 degrees, a shoulder diameter (SD) of 16 mm, and with a straight square tool pin profile (TPP). ANOVA revealed the relevance of all five characteristics, with rotational speed being the most influential, accounting for 43.56% of the entire result. A confirmation experiment done under ideal conditions revealed a significant improvement in total weld quality of 19.06%.

The influence of tool shoulder size and plate position on the characteristics of friction stir welded different aluminum alloys

ABSTRACT Welding is a main manufacturing method for fabricating various engineering components. Fusion welding techniques encounter solidification associated problems while joining light weight structures. Friction stir welding is a solid state welding technique that is developed to address these shortcomings. As the superior conductive properties of AA6101-T6 and AA1350 aluminum alloys, they are frequently utilized in electrical industries. The goal of this study is to examine how the plate position and tool shoulder diameter (D) affect the qualities of these dissimilar Al-alloys joints. It is discovered that plate positioning is the most influential welding parameter in determining the tensile properties of weldment. Furthermore, the joint fabricated with AA6101-T6 as an advancing side material and a 15 mm tool shoulder diameter produces sufficient weld reaction temperature, better plastic flow and tensile properties. However, the joint fabricated with AA1350 as an advancing side material and 12 mm tool shoulder diameter generates inadequate reaction temperature, poor plasticization, and tensile properties. The formation of precipitates as well as the interface layer at the weld nugget is greatly dominated by the tool shoulder size, which affects the wear properties of weldment.

Impact of the tool shoulder diameter to pin diameter ratio and welding speed on the performance of friction sir-welded AA7075-T651 Al alloy butt joints

This study investigates the friction stir welding (FSW) of aluminum alloy 7075-T651, mainly focusing on managing heat generation during the process. The critical parameters influencing heat amount and the material flow including FSW tool shoulder diameter (SD) and travel speed (TS) were investigated. Two far different SD of 10 mm and 20 mm with constant pin diameter (PD) of 5.70 mm that resulted in PD: SD ratios of 1:1.75 and 1: 3.50, respectively, were employed. Furthermore, three different travel speeds of 25, 50, and 75 mm min−1 at a constant rotation rate of 600 rpm were used in combination with the two PD: SD ratios. The macrographic and radiographic results indicated that the smallest PD: SD ratio has successfully achieved sound friction stir welded (FSWed) joints for the same travel speeds. Results also indicated that a significant amount of material deformed under a high PD: SD ratioat a high TS of 75 mm min−1, while flash increased with reducing PD: SD ratio.Mechanical properties were compared, revealing that hardness in the nugget zone (NZ) decreased with a lower TS of 25 mm min−1. A small PD: SD ratioallowed for more symmetrical heat distribution, supported by the hardness map. The ultimate tensile strength decreased with increasing TS, and the highest ultimate strength, reaching 319 MPa, was observed with a 1:1.75 ratio and TS of 25 mm min−1. X-ray diffraction analysis (XRD) found an increase in peaks with increasing shoulder diameter and the number of peaks increased with decreasing travel speeds.

Optimization of parameters and formulation of numerical model employing GRA–PCA and RSM approach for friction stir welded Ti–6Al–4V alloy joints

In this work, an endeavour was made to determine the impact of the tool’s shoulder diameter, pin profile, rotational and traverse speeds on the mechanical properties of the friction stir welded namely Ti–6Al–4 V alloy joints. A total of 21 experiments were carried out based on the central composite design (CCD) concept of response surface methodology (RSM). A quadratic regression based numerical model was formulated to ascertain the relationship amidst the parameters of FSW process and the mechanical properties of the fabricated Ti alloy joints. Analysis of variance (ANOVA) was employed to confirm the importance of parameters and their interactive impacts. Optimized process parameter combinations were ascertained by grey relation based analysis (GRA) was coupled together with principal component analysis (PCA), a hybrid based approach. Single score of GRG based response was determined and GRG scores were ranked for all experiments. 1st rank was attained by the experiment no. 20 possessing a GRG score of 2.9989. Optimized values of 25 mm shoulder diameter having a taper cylindrical pin geometry employed at a tool traverse speed of 40 mm min−1, rotational speed of 1400 rpm resulted in the generation of flaw free Ti alloy joint possessing a largest tensile strength of 809.8 MPa, yield strength of 778.7 MPa and percentage of elongation of 6.9%. SEM based fractography of Ti alloy joint specimens announced that taper cylindrical pin geometry along with 25 m shoulder diameter of employed tool have an inevitable part in generating frictional heat in ideal volumes and a perfect stirring action during FSW process.

Prediction of corrosion rate for friction stir processed WE43 alloy by combining PSO-based virtual sample generation and machine learning

The corrosion rate is a crucial factor that impacts the longevity of materials in different applications. After undergoing friction stir processing (FSP), the refined grain structure leads to a notable decrease in corrosion rate. However, a better understanding of the correlation between the FSP process parameters and the corrosion rate is still lacking. The current study used machine learning to establish the relationship between the corrosion rate and FSP process parameters (rotational speed, traverse speed, and shoulder diameter) for WE43 alloy. The Taguchi L27 design of experiments was used for the experimental analysis. In addition, synthetic data was generated using particle swarm optimization for virtual sample generation (VSG). The application of VSG has led to an increase in the prediction accuracy of machine learning models. A sensitivity analysis was performed using Shapley Additive Explanations to determine the key factors affecting the corrosion rate. The shoulder diameter had a significant impact in comparison to the traverse speed. A graphical user interface (GUI) has been created to predict the corrosion rate using the identified factors. This study focuses on the WE43 alloy, but its findings can also be used to predict the corrosion rate of other magnesium alloys.

СРАВНИТЕЛЬНАЯ ХАРАКТЕРИСТИКА АНТРОПОМЕТРИЧЕСКИХ И БИОИМПЕДАНСОМЕТРИЧЕСКИХ ПОКАЗАТЕЛЕЙ РОССИЙСКИХ И ИНОСТРАННЫХ СТУДЕНТОВ СЕВЕРО-ВОСТОЧНОГО ФЕДЕРАЛЬНОГО УНИВЕРСИТЕТА

To study the adaptation processes of foreign students, the most accessible and informative is to determine their morphofunctional status. The purpose of the study was to conduct a comparative characterization of anthropometric and bioimpedance indicators of yakut and arab students. Materials and methods: 166 young men of yakut nationality and 43 arab boys, natives of Egypt, whose average age was 19,9±0,25 years, were examined. All the examined were 1st year students of the Medical Institute of the North-Eastern Federal University. Anthropometric and bioimpedance measurements were carried out, and an index assessment of physical development was given. The methods of parametric and nonparametric statistics are used. Results and conclusion: Significantly high indices of body weight, chest circumference, buttock girth and antero-posterior chest diameter were established in arab boys. Yakuts have significantly higher shoulder diameter values. Arab boys are more likely to register persons with increased body density according to the Yarho-Kaupe index, high physical development according to the Rohrer index, persons with increased body weight and obesity according to the body mass index. The indices of active and reactive tissue resistance were significantly higher in yakut boys. Significantly high values of total hydration, musculoskeletal mass and lean mass were recorded in arab boys. Among the yakut boys, a significantly large proportion of persons with a high value and the absence of persons with a low value of the phase angle were identified. The obtained results of bioimpedance analysis indicate the best condition of the body's cells, the level of overall performance and metabolic intensity in yakut boys.

State-of-the-art survey of literature for finding an effective solution to mitigate the exit-hole defect in friction stir welded samples

Friction stir welding is a solid-state welding process among the most important processes used for welding materials that the conventional welding process cannot weld. The joining of two metals occurs by heat generated due to the friction between the non-consuming rotating tool surface and workpiece. This technology is extensively used in the automobile, railway, maritime and aerospace industries. There are some defects that occurred in this process such as the tunnel, kissing bond, incomplete root penetration, excessive flash and void, those can be overcome by modifying the process parameters namely tool rotational speed, welding speed, downward force, shoulder diameter, shoulder geometry, tool pin geometry, tool pin diameter, tool pin length and tilt angle. The inevitable defect is the exit-hole left after the retraction of a rotating tool at the end of the weld cycle. The present work reviews different repair techniques for the exit-hole of the welded joints. This article discusses various exit-hole repairing techniques pertinent to the method, process parameters, material, plate thickness and the defect that emerges using these techniques. The current survey also presents a few future research opportunities in this field that can be carried out to mitigate the exit-hole defect.

Development of a fuzzy logic model for predicting the quality of micro friction stir spot welding (µFSSW) using particle swarm optimization

Micro Friction Stir Spot Welding (µFSSW) is crucial in microelectronics and precision manufacturing. It requires a comprehensive understanding of the complex connections between various parameters to achieve the highest quality welds. This study aims to improve the prediction of µFSSW weld quality by incorporating advanced optimization techniques. Fuzzy Logic Optimization is used to model uncertainties, and Particle Swarm Optimization (PSO) is employed to fine-tune parameters for improved accuracy. The fuzzy logic system utilizes Gaussian functions as membership functions, organized with nine rule bases. The results clearly demonstrate that the fuzzy logic model greatly enhances accuracy when combined with Particle Swarm Optimization. The refined model improves precision for pin diameter, shoulder diameter, Thermo-Mechanically Affected Zone (TMAZ) area, and cross-tensile strength. The PSO-optimized model shows lower accuracy in predicting plunge depth and shear tensile strength. The ongoing decline in Root Mean Square Error (RMSE) values highlights the complexity of the results. The optimization significantly improves the model’s ability to predict specific weld quality metrics, as demonstrated by the pin diameter’s reduced RMSE value of 0.07. The collective results showcase an optimized Fuzzy Logic System (FLS) model adept at accurately predicting µFSSW weld quality, demonstrating adaptability across diverse conditions. The discernible increase in accuracy, reaching up to 76 % following the optimization of the fuzzy logic model with PSO, serves as a testament to the efficacy of the employed methodologies in advancing the precision and reliability of µFSSW weld quality predictions