Friction Stir Welding Process Parameters Research Articles

Investigation of microstructure and microtexture development and its correlation with mechanical and formability behavior of dissimilar friction stir welded AA6061 and AA5754 sheets

The major attention of the automotive, aerospace, and marine industries currently is towards light-weight structural parts, and this can be achieved by the use of the tailor-welded blanks (TWBs). Using Al alloys as a member of the TWBs lessens the structural weight further, but conventional fusion welding of these alloys is often associated with defects such as porosity, manifestation of segregation and under-fill formation. Friction stir welding (FSW) is a feasible approach not only for producing welds with minimal defects but also for their enhanced formability, which finds extensive applications across industries. Due to its capability of completely negating the rolling directional properties of the as-received sheet, FSW increases the uniformity in the strain distribution during the course of deformation. In the present study, the objective was to perform FSW for dissimilar materials (with advancing side AA6061 and retreating side AA5754 sheets) with a similar thickness of 1.5 mm and to investigate the formability behavior of the TWBs. The effect of different FSW process parameters like rotational speed (950 rpm, 1100 rpm, 1250 rpm, and 1400 rpm) and traverse speed (50 mm/min, 75 mm/min, and 100 mm/min) which were selected based on visual inspection and macrostructure studies of the welds, was investigated on the formability and mechanical behavior of welded AA6061 and AA5754 sheets. Tensile tests were performed for base materials along with the specimens welded at different process parameters according to ASTM E8 standard to evaluate the mechanical properties. Micro-hardness tests were performed at several locations of the cross-section in the transverse direction to the weld in either side. The assessment of formability was executed by deforming the as-received and welded specimens in uniaxial strain paths, plane strain paths, and biaxial strain paths using Limit Dome Height (LDH) tests. Tensile test evaluation of 1250 rpm–50 mm/min, 1250 rpm–75 mm/min, 1400 rpm–50 mm/min, and 1400 rpm–75 mm/min parameter combinations exhibited cracks away from the weld center towards the advancing side (AA6061 side) of the specimens, indicating good quality of the welds, which was in agreement with the stir zone macrostructures. The micro-hardness distribution plots also showed a drop in the hardness in the TMAZ of the advancing side, making it the weakest region of the weld. It has been observed from the LDH test that the formability of all the FSWed specimens was intermediate to the formability of AA5754 (superior formability) and AA6061 (inferior formability), irrespective of the strain paths that might be correlated to their corresponding strain hardening exponents. In the case of uniaxial and plane strain paths in the welded specimens, the failure was towards the advancing side, which was in agreement with the tensile properties, but in the case of biaxial stretching, it was failing at the weld center due to their corresponding microstructural characteristics. An abnormal behavior was witnessed in the equibiaxial stretching, i.e., the minor strain attained for all the welded specimens was significantly less. Comprehensive studies on microstructure and microtexture were performed on the un-deformed and deformed specimens to investigate the peculiar behavior, and it was inferred that the initial local misorientations play a pivotal role in determining the grain orientation spread (GOS) post-deformation. It was further observed that the average GOS values were analogous across all the deformed welded samples in their respective strain paths. It's noteworthy that the presence of the Cube texture component in the biaxial strain path significantly mitigated the impact of the Goss texture, resulting in the peculiar behavior i.e. a notable decrease in the minor strain observed in the deformed welded specimens in the biaxial strain path.

Experimental investigation into friction stir welding of AA6061-T6 and magnesium AZ31B alloy using copper backing plate

Aluminium-magnesium alloys are lightweight and possess superior properties, making them ideal for applications in aerospace, railway, automotive, and marine structures. However, these alloys are challenging to fabricate using traditional fusion welding due to various metallurgical issues. This study investigates the feasibility of joining 3 mm thick dissimilar alloys of aluminium AA6061-T6 and magnesium AZ31B using the friction stir welding (FSW) process with copper as a backing plate. The effects of FSW process parameters, including tool rotational speed (380, 545, 765 rpm), weld speed (20, 31.5, 50 mm min−1), and tilt angle (1°, 2°, 3°), on tensile properties were examined using Taguchi-based grey relational analysis. Temperatures were recorded during the FSW process under different conditions on both sides of the joint. The highest tensile strength of 130.72 MPa, with a joint efficiency of 67.85%, was achieved at a tool rotational speed of 765 rpm, a welding speed of 50 mm min−1, and a tilt angle of 2°. Analysis of variance (ANOVA) for the grey relational grade indicated that the tilt angle had the highest percentage contribution of 43.60%. This study demonstrates the significant influence of FSW parameters on the mechanical properties of aluminium-magnesium joints and highlights the optimal conditions for achieving high joint strength and efficiency.

Assessment of the Thermomechanical Behavior and Microstructure of AA 7075-T6 Aluminum Alloy Lap Joints at Optimal Predicted FSW Process Parameters

The lap joints of AA 7075-T6 aluminum alloy were assembled using the friction stir welding (FSW) technique. Experimental studies were performed to characterize the thermomechanical properties of these welds. The main goal of this research was to comprehensively assess the thermomechanical behavior of AA 7075-T6 aluminum alloy under FSW conditions. Tests were carried out at a tool rotational speed of 1320 rpm and at two advancing speeds of 70 mm/min and 120 mm/min, selected based on a previous study aiming to optimize the heat input during the FSW process. The experimental investigations involved the characterization of temperature profiles during welding, mechanical properties such as microhardness and tensile strength, and microstructure examination at the two advancing speed conditions. This study revealed that the welding speed has an obvious influence on the material thermal behavior during the FSW process. Indeed, the peak temperature obtained with a lower welding speed (70 mm/min) was higher by almost 10% compared to that obtained with a higher speed (120 mm/min). Moreover, by increasing the welding speed, the mechanical characteristics, such as microhardness and tensile strength, were increased by almost 5% for the mean microhardness and 6% for the ultimate tensile strength. Additionally, the microstructure examination demonstrated that, by decreasing the welding speed, more interaction between the tool and the material is observed, resulting in a deeper stir zone due to increased heat dissipation downwards into the material, affecting the thermal profile and influencing the resulting mechanical properties of the welded joint.

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.

A New Approach in Part Design for Friction Stir Welding of 3D-Printed Parts with Different Infill Ratios and Colors.

Parts produced using a 3D printer are combined with friction stir welding (FSW). In the FSW processing of parts with a low infill ratio, welding errors occur due to a lack of material. In this study, plates were created using two different-colored PLA Plus filaments with different infill ratios in the weld area (20%, 60%, and 100%). Triangular pin geometry, different feed rates (20, 40, and 60 mm/min), and different tool rotation speeds (1250, 1750, and 2250 rpm) were used as FSW process parameters. Tensile testing was performed to determine weld strength and hardness measurements, and visual inspections were performed. Color measurements were made on the test samples before and after the welding process, and the relationship between welding performance and color was evaluated. The best welding strength was obtained as 17.83 ± 0.68 MPa at a feed rate of 20 mm/min, a tool rotation speed of 1750 rpm, and a part with a 60% infill ratio in the welding zone. In the sample with the best weld strength, the temperature was measured as 198.97 °C. Color changes in the weld area of parts with 60% and 100% infill ratios were measured between 78.9-82.2 and 79.1-84.5, respectively. It was determined that the color change decreases as the weld strength increases in these parts. The results show that with the proposed new part design, the FSW method can be used at low infill ratios, and the weld strength can be evaluated based on the color changes in the weld zone.

Investigation of The Weldability of PLA Plus Sheets with Different Infill Ratios by Friction Stir Welding

Although the joining processes of plastics are typically carried out through welding, adhesive bonding, or mechanical fastening elements, the production of complex and large parts often requires welding technology. In this study, the effect of part infill ratio (20%, 40%, 60%, 80%, and 100%) on the welding strength of 3D printed PLA Plus parts was evaluated through friction stir welding (FSW). Tensile tests and temperature measurements were carried out to examine the effects of friction stir welding process parameters (feed rate: 50 and 100 mm/min and rotational speed: 1000 and 1500 rpm) on the structure and mechanical properties of friction stir welding. Moreover, visual inspections were performed to detect defects in the weld zone. Compared to the PLA Plus samples given as reference according to the infill ratios, the highest welding strengths were obtained at 80%, 60% and 100% infill ratios (29.4 MPa, 17.47 MPa and 41.12 MPa and 112.38%, 97.48%, 87.04% efficiency, respectively). As a result, it was determined that at low infill ratios (20% and 40%), the weld quality was negatively affected, and a surface tunnel defect occurred in the weld zone. It has been determined that the weld quality in FSW is significantly affected by the temperature occurring during the process. The study has shown that parts printed at different infill ratios, especially on a 3D printer, can be combined with friction stir welding and that the efficiency of the welding process can be increased by optimizing the infill ratios.

Efficiency Improvement of Friction Stir Welding Parameters on AZ91 Magnesium Alloy Joints

Abstract: Friction Stir Welding (FSW) is a solid-state welding that permits an intensive formof parts and geometries to be welded with great nature of joints. The use of high-quality Magnesium alloys is extending in shipbuilding industry, particularly for the advancementof naval warships, cruise ships, littoral surface craft and merchant ships. FSW advancementhas been seemed to have various focal points for the exploitation of Magnesium alloys structures, as it is a minimal effort welding process. The objective is to come across the optimum levels of the process parameters in which it yields maximum tensile strength andbetter hardness. A three-factor, three-level design is utilized for optimizing the FSW process parameters and a Taguchi L9 orthogonal array experimental set up is used to anticipate the responses. The system parameters considered are Rotational speed, Transverse speed and the Tool tilt angle. The Friction stir welding is processed for butt joining of Magnesium alloys (AZ91) plates with 6 mm thickness. Tensile testing is attempted on dog-bone kind test specimen for Magnesium alloys. Analysis of Variance (ANOVA) has been used to analyze the effect of different parameters regarding the responses. The microstructural attributes of the welded segments, including base metal, heat affected zone (HAZ), Thermo Mechanically Affected Zone (TMAZ) and Stir Zone (SZ) are examined through Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) analysis carried out to quantify the chemical element allocation at the weld interface. The observed optimum condition for Magnesium alloys (AZ91) is 560 rpm, 60 mm/min and 1 degree.

Behavior of microstructure and mechanical properties in the stir zone of friction stir welded ME21 magnesium alloy

In this work, Friction Stir Welding (FSW) of magnesium alloy ME21 in a T-profile is performed with a relatively higher welding speed than usual in this material. The FSW process parameters, i.e., rotational speed and welding speed, are investigated focused within its inherent microstructural and mechanical properties on the stir zones of the welded joints. The concept of a Stribeck Curve in tribological systems, is transferred to FSW to explain the transition between insufficient and full plasticization of the material. The stir zone presented a strong grain refinement due to the activation of dynamic recrystallization along with a completely changed crystallographic texture and orientation due to FSW. The hardness is overall improved, while the ductility and tensile strength were reduced. The microstructure and texture in the stir zone were not strongly influenced by changes in the welding parameters.

Experimental Modeling and Multi-Response Optimization in Friction Stir Welding Process Parameters of AA2024-T3 Using Response Surface Methodology and Desirability Approach

Experimental Modeling and Multi-Response Optimization in Friction Stir Welding Process Parameters of AA2024-T3 Using Response Surface Methodology and Desirability Approach

Development of FSW Process Parameters for Lap Joints Made of Thin 7075 Aluminum Alloy Sheets.

The article describes machine learning using artificial neural networks (ANNs) to develop the parameters of the friction stir welding (FSW) process for three types of aluminum joints (EN AW 7075). The ANNs were built using a total of 608 experimental data. Two types of networks were built. The first one was used to classify good/bad joints with MLP 7-19-2 topology (one input layer with 7 neurons, one hidden layer with 19 neurons, and one output layer with 2 neurons), and the second one was used to regress the tensile load-bearing capacity with MLP 7-19-1 topology (one input layer with 7 neurons, one hidden layer with 19 neurons, and one output layer with 1 neuron). FSW parameters, such as rotational speed, welding speed, and joint and tool geometry, were used as input data for ANN training. The quality of the FSW joint was assessed in terms of microstructure and mechanical properties based on a case study. The usefulness of both trained neural networks has been demonstrated. The quality of the validation set for the regression network was approximately 93.6%, while the errors for the confusion matrix of the test set never exceeded 6%. Only 184 epochs were needed to train the regression network. The quality of the validation set was approximately 87.1%. Predictive maps were developed and presented in the work, allowing for the selection of optimal parameters of the FSW process for three types of joints.

Intelligent Prediction of FSW Physical Quantity and Joint Mechanical Properties

Friction stir welding (FSW) process parameters influence welding temperature field and axial force, which affect welding strength. At present, how the FSW process parameters of aluminum alloy 2219-T8 thick plates influence process physical quantity and how the process physical quantity changes the tensile strength about the welded joint are unknown. We focus on the intelligent prediction of FSW temperature, axial force, and mechanical properties, to provide a basis for FSW process control of aluminum alloy 2219-T8 thick plate. Firstly, we conducted the FSW experiment of aluminum alloy 2219-T8 thick plate. Then, we input the welding process parameters, set up a prediction model by particle swarm optimization-back propagation (PSO-BP) neural network to predict the peak temperature and axial force. Finally, we input the peak temperature and axial force, use genetic algorithm-back propagation (GA-BP) neural network to establish a weld tensile strength estimation model, and comply with the prediction of tensile strength.

Examination and Optimization of Friction Stir Welding Process Parameters of AA6092 Alloys

Examination and Optimization of Friction Stir Welding Process Parameters of AA6092 Alloys

Ispitivanje i optimizacija površine zavara i mehaničkih performansi termoplastičnih delova proizvedenih aditivnom proizvodnjom i zavarenih zavarivanjem trenjem

This study presents an experimental investigation into the weldability of ABS M30 (acrylonitrile butadiene styrene) plates produced by Additive Manufacturing (AM) using Friction Stir Welding (FSW). The effects of FSW process parameters on the yield stress and their optimal levels were determined using the Taguchi method. The optimal welding parameters were found to be a 16 mm tool shoulder diameter, 800 rpm tool rotation speed, and 10 mm/min traverse speed. The weld area of each sample welded using FSW was examined at a macroscopic level. The direction of tool rotation significantly affects the quality and strength of the FSW. When the FSW was performed with a clockwise rotation of the welding tool, a perfect weld could not be achieved. The tunnel effect resulted in gaps in the weld area of the samples at high rotation speeds. Differences were observed in the density between the weld area of the samples and the main parts.

Effect of process parameters on friction stir welding of aluminium alloy AA6082–T6 with an interlayer using response surface methodology

In the present study, the effects of variation of process parameters on the mechanical properties of friction stir welded A6082–T6 aluminium alloy joints with Zinc (Zn) interlayer are experimentally investigated. Four process parameters, viz. rotational speed, welding speed, interlayer thickness and tool pin diameter are selected to fabricate the Friction Stir Welding (FSW) joints. After filling the Zn particles into the gap maintained between the plates, FSW is performed using different process parameters. Thereafter, tensile and impact strength tests are performed to evaluate the performance of the joints. It is analyzed that the tensile and impact strength of the joints vary from 121 to 197 MPa and 6 to 17 J, respectively. Subsequently, mathematical models are developed using Response Surface Methodology (RSM) to predict the effect of FSW process parameters on the tensile and impact strength of joints. Analysis of Variance (ANOVA) is used to check the level and degree of direct effect of process variables on the tensile and impact strength of the joints. It is observed from the results that tool rotational speed is the most influential process parameter, which enhances the mechanical properties of FSW joints, whereas an increase in welding speed reduces the mechanical properties of the joints.

A comparative study of multiple-criteria decision-making methods for selecting the best process parameters for friction stir welded Al 6061 alloy

The selection of welding process parameters is a tedious operation that demands the process evaluation. Multi criteria decision-making strategies for assessing friction stir welding (FSW) process parameters are scanty. Therefore, a comparative study between five different multi-criteria decision-making methods was applied within friction stir welding process to show the deviations in the ranking of the alternatives. The goal is to find the welding parameters (including rotation speed, shoulder diameter, and travel speed) that result in the highest performance scores or rankings for the considered responses, such as ultimate tensile strength, hardness, and surface roughness. In the following, different decision-making strategies (including TOPSIS, GRA, hybrid GRA-TOPSIS, CoCoSo, and MACROS) are applied to calculate the weight of all different decision-making using entropy. The proposed methods in this study are validated by representing the accurate decision maker’s preferences and consideration of uncertainty. The decision-makers choose GRA-TOPSIS and TOPSIS as the best approach with higher efficiency. GRA was determined to be more time-consuming and to have the most variety of outcomes, whereas CoCoSo and MACROS were unable to produce a definite best result. The study is highly promising for researchers and machining specialists to produce quality friction stir welds.

Effect of friction stir welding on microstructure and foaming mechanism of rolled-state anisotropic powder

Friction stir welding (FSW) has a significant impact on welding aluminum foam sandwich (AFS) precursor. Yet, the understanding of the microstructure and foaming process on rolled-state powder of welded precursor remains limited. This study exploited the single-pass double-sided forming welding approach to weld the AFS precursor, while the impact of different process parameters of FSW on the microstructure of rolled-state powder was evaluated. Meanwhile, the foaming process of anisotropic powder at different directions was observed in-situ using synchrotron radiation. The results display that FSW transforms gap-like voids, which were ∼20 µm in width and 100–400 µm in length, into circular voids with a diameter of ∼6 µm in the powder at the weld zone (WZ). The welding process eliminates powder agglomeration aggregation and increases the relative density (>97%) of rolled-state powder. However, the low thermal conductivity of the rolled-state powder (117 W·m−1·K−1) leads to a tunnel defect at the root of the WZ. In addition, in-situ observation experiments of the foaming process found that the bubble nucleation of rolled-state powder exhibits anisotropic characteristics, and the welding process causes a transition in the types of bubble nucleation in the WZ region. This study demonstrates the feasibility of improving the anisotropy of powders caused by processing methods to obtain an isotropic pore formation and foam expansion by FSW technology.

Influence of friction stir welding process parameters and statistical behaviour of the novel interlock aluminum alloys joint with SiCp reinforcement

Influence of friction stir welding process parameters and statistical behaviour of the novel interlock aluminum alloys joint with SiCp reinforcement

Optimization of process parameters for producing AA6061/SiC nanocomposites by friction stir processing Optimization of process parameters for FSW AA7075/TiC, B4C, Al2O3 nano Hybrid composites by Taguchi technique


 
 
 
 A significant area of research now being pursued by the foundry industry is how to enhance the mechanical properties of aluminium alloys by reinforcing them with micro ceramic particles. The mechanical and Microstructural studies of commercial AA 7075 stir die castings reinforced by various weight ratios of titanium carbide (TiC), boron carbide (B4C), and aluminium oxide (Al2O3) have been examined in the current study. Further, friction stir welding (FSW) process has been carried out based L16 Orthogonal Array (OA). Optimal decision making approach for the improvement of Friction Stir Welding (FSW) process was performed by Taguchi method. Investigations were conducted on the effects of three variables on UTS, including rotating speed, transverse speed and tilt angle. The maximum ultimate tensile stress was found to be around 162 M Pa for sample 8 (1.5 wt% TiC, 0.5 wt% B4C and 0.8 wt% Al2O3) welded at speed 900 rpm, feed 45 mm/min, and Tilt angle 2.50.
 
 
 

Multi objective Optimizations of friction stir welding process parameters for reinforcement of copper particles in aluminum alloy using Taguchi based grey relational analysis (GRA) and ANOVA.

In this paper, optimize process parameters of friction stir welding for reinforcement of copper particulate in between aluminum alloys. It is to boost the thermal conductivity and mechanical properties of base metals. Two dissimilar aluminum alloys with different mechanical properties .AA6061-AA6063. successfully joined. In addition, the introducing copper particles of 325 mesh size in between aluminum alloy 6061 and 6063. It is a direct application of rotating non-consumable friction stir welding tool plunged for reinforcement. Introduction of a copper particle in between aluminum alloy is a unique system in the solid-state welding process. Taguchi method as an optimization tool used to design process parameters. Afterward, welding samples were cut in the desired size and progressed for a further test such as tensile and hardness test. Finally, it is observed to have improved mechanical strength in minimum spindle speed i.e.1000 rpm and welding speed 20 mm/min. Study also shows feasibility of GRA, Hypothesis .Z-test. test and ANOVA with Taguchi technique.

Thermomechanical Modeling of Material Flow and Weld Quality in the Friction Stir Welding of High-Density Polyethylene.

A thermomechanical model of the friction stir welding (FSW) of high-density polyethylene (HDPE) was developed by incorporating a Coupled Eulerian-Lagrangian (CEL) approach. A Johnson Cook (JC) material model of HDPE was developed through experimentally generated strain-rate- and temperature-dependent stress strain data. Two sets of FSW process parameters with minimum and maximum weld defects were numerically modeled. The numerically calculated temperature distribution, material flow and flash and potential defects were validated and discussed with the experimental results. Tracer particles allowed to visualize the material movement during and after the tool had traversed from the specified region of the workpiece. Both numerical models presented similar maximum temperatures on the upper surface of the workpiece, while the model with high traverse speed and slow rotational speed had narrower shoulder- and heat-affected zones than the slow traverse, high rotational speed model. This contributed to the lack of material flow, hence the development of voids and worm holes in the high traverse speed model. Flash and weld defects were observed in models for both sets of process parameters. However, slow traverse, high rotational speeds exhibited smaller and lesser weld defects than high traverse, slow rotational speeds. The numerical results based on the CEL approach and JC material model were found to be in good agreement with the experimental results.