Tool Pin Diameter Research Articles

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.

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.

Effect of high tool rotational speed and pin diameter on mechanical properties, microstructure and formability of friction stir tailor welded blanks

ABSTRACT On the tensile characteristics, microhardness, microstructure, and formability of tailor-welded blanks of aluminium alloys (AA) 6082-O and AA5083-O were explored in this study. The influence of these process parameters on Friction stir welded (FSWed) regions such as the weld nugget zone (WNZ), thermomechanical affected zone (TMAZ), and the heat-affected zone (HAZ) has been studied. Response surface methodology (RSM) was utilised to investigate the impact of process factors. Using four components and three levels, 30 trials were run. There is a direct correlation between FSW input process parameters and output responses such as tensile strength, yield strength, elongation, microhardness value and dome height. The constructed model is tested for appropriateness using ANOVA technique. The experimental and predicted findings were well correlated. Scanning electron microscopy (SEM) was used to evaluate the microstructure of the friction stir welded regions such as WNZ, TMAZ, and HAZ. The maximum hardness was achieved at 4 mm pin diameter with all rotational speed due to finer grain structure formed at WNZ region. The experimental and optimised values were compared and agreed.

A multi-objective optimization using response surface model coupled with particle swarm algorithm on FSW process parameters

In this study, multi-objective optimization of mechanical properties in friction-stir-welding of AH12 1050 aluminum alloy is performed using a combination of the response surface method and multi-objective particle swarm optimization algorithm. The process parameters are considered as tool pin diameter, shoulder diameter, rotational speed, feed speed, and tool tilt angle. The heat-affected zone’s yield strength, fracture strain, impact toughness, and hardness on the advancing and retreating sides are selected as the objective functions. Threaded and simple conical pins are utilized to evaluate the effect of the pin geometry on the specimen mechanical properties. Optimization model outputs are in agree with the obtained experimental results. The effects of process parameters on the mechanical properties of the friction-stir-welded sheets are studied. Results reveal that the lower rotational speed and higher feed speed improve the material strength and hardness. Moreover, the microstructural analysis demonstrates that the proposed methodology can achieve a fine-grained structure with the minimum defects. Improvement in the material flow is observed for the threaded cylindrical pin compared with the conical pin due to the geometric shape of the tool pin leading to more functional mechanical properties. It is found that the combination of the response surface methodology and the multi-objective particle swarm algorithm led to the modeling and optimization of the process with outstanding accuracy and low experimental cost.

Influences of Friction stir tool parameters for joining two similar AZ61A alloy plates

The welding of magnesium alloy plates is highly important to utilize lightweight applications such as aircraft, automotive, and space sectors. In this research, Friction stir welding (FSW) of two similar AZ61A Magnesium alloy plates has been performed to obtain the maximum micro-hardness and tensile strength. The tool parameters such as tool revolving speed, Tool traveling speed, tool force, tool pin, and shoulder diameters have been modified during the welding experiments. The percentage of contributions and significant various tool parameters on micro-hardness and tensile strength have been analysed using Taguchi’s technique. The tool pin diameter and tool revolving speed are highly contributed factors to enhance the micro-hardness and tensile strength than tool revolving speed and shoulder diameter. The predicted best tool parameters values have been evaluated by confirmation experiments.

Investigation of Factors Affecting Friction Stir Welding of Polyethylene by ANOVA Analysis

The variables that are effective in joining high density polyethylene sheets by friction stir welding (FSW) have been investigated. In order to understand the effects of welding parameters, using Taguchi optimization, tool rotation speed, feed rate, shoulder diameter and pin diameter values were selected in a wide range. The results obtained with Taguchi optimization method were evaluated according to the highest / the best signal-noise ratio. Macro photographs taken cross-sectional view taken the weld seam, SEM images and hardness measurements were used to evaluate. As a result of the evaluation, the accuracy of the optimization was found to be approximately 96 %. As a result, feed rate and shoulder diameter were determined as the most effective parameter affecting the welding quality and welding performance. These two parameters (shoulder diameter and feed rate) have found to effect of approximately 65 % on tensile strength, weld quality and hardness. Finally, it has obtained that the most effective welding parameter was the shoulder diameter with 40.81 %.

The effect of tool pin size and taper angle on the thermal process and plastic material flow in friction stir welding

Friction stir welding (FSW) tool pin, as a critical component of FSW tool, plays an important role in determining the final joint properties by affecting the heat generation, plastic material flow, welding loads, and so on. However, the effects of tool pin on heat and mass transfer in FSW are not elucidated and quantitative studied. In the present study, a validated model was adopted to quantitatively analyze the effects of pin size and taper angle on the thermal process and plastic material flow in FSW. The effects of pin root diameter, pin tip diameter, and pin taper angle on heat and mass transfer in FSW were quantitatively investigated, respectively. It reveals that the torque and transverse force imposed on the pin are increased with the increase of the pin diameters (including its root diameter, its tip diameter, and its size in condition of constant taper angle), while the total tool torque varies a little for the tool pin diameter considered in this study. When the pin diameters increase, the viscosity of the materials near the pin is decreased, while the temperature as well as the flow velocity is increased. More plastic material near the tool could rotate around the tool with an increase of the pin diameter. The TMAZ boundary is enlarged with larger pin diameters in FSW. Particularly, the shear layer thickness of the same horizontal plane in the range of 1 mm < z < 5 mm is significantly enlarged with an increase of pin root diameters. However, the shear layer thickness of the same horizontal plane in the region of z < 5 mm is increased when using a larger pin tip diameter. In addition, maximum width of TMAZ boundary at the top surface of workpiece was not affected by pin diameters. The model is validated by experimental results. It could lay a solid foundation for optimizing the tool pin size and taper angle in FSW.

Effect of tool material and process parameters on friction stir weld formation of maraging steel

ABSTRACT 18% Ni maraging steel is an ultra-high strength steel widely used in defence and aerospace applications. Fusion welding of maraging steel is encountered with a drop in properties due to the segregation of alloying element and hence, solid-state welding process such as friction stir welding (FSW) is a possible alternative. However, welding of high strength material using FSW is a challenge considering the tool material durability, tool material cost, and selection of tool geometry and process parameters. Therefore, the main focus of this paper is towards the selection of tool geometry, tool material, and process parameters that will result in least tool wear/failure in addition to obtaining defect-free welds of maraging steel using FSW. It was observed that polycrystalline cubic boron nitride (PCBN) and tungsten-molybdenum are durable tool material for welding maraging steel. It is recommended to use a minimum tool pin diameter (top 12 mm and bottom 8 mm) and shoulder diameter (20 mm) below which failure of pin and surface defects are encountered during FSW. It is also observed that there exists a narrow range of tool rotational speed (250–450 rpm) and tool travel speed (25 mm/min) at which defect-free maraging steel welds can be obtained.

Influence of D/d ratio on stir zone formation and properties of friction stir welded dissimilar joints of AA5086 and AA6061 aluminum alloys

A well-known method known as Friction stir welding (FSW) is used for combining materials that are distinct from each other. In FSW, a profiled spinning shoulder shifts between sheets of the sections that are to be connected. Heat is produced due to the friction between the base and the tool shoulder when the tool is turning along the weld line. In contrast to fusion welding processes, the heat produced is lower. In these works, the effect of macro/microstructures characterization and the tensile characteristics of the dissimilar AA5086 and AA606I aluminum alloys on the ratio of tool shoulder diameter and tool pin diameter (D/d) used in the FSW were explored. This study shows the superior tensile characteristics on welding components in contrast to the counters made of the sealing units made using a tool profile of threaded cylinders, a 1 ° tool tilting angle, tool rotation speed of 1100 rpm, the welding speed of 22 mm/min and the shoulder diameter is 21 mm. Further, the joints fabricated using threaded cylinder tool profile exhibited superior macro structure compared to its counter parts.

Multi responses taguchi optimization using overlaid contour plot and desirability function

Optimization is the process of getting an optimal response. The taguchi design is an experimental design that is often used to get robust responses. In the multi-response Taguchi design, the optimization process is carried out by considering all responses simultaneously. Cases study used in this research is aluminum production cases with four treatments, namely tool rotational speed, welding speed, shoulder tool diameter and pin diameter. Each treatment was tried with three levels. Optimized responses are tensile strength, average microhardness and average grain size.The purpose of this research is determining the point of optimization using response surface method and desirability function. The optimization results obtained are tool rotational speed of 1100 RPM, Welding speed of 40 mm/min, Shoulder diameter of 21 mm, and pin diameter of 5.4 mm.

Retracted] Parameters Optimization of Dissimilar Friction Stir Welding for AA7079 and AA8050 through RSM

Aluminium alloy is widely used in engineering application, and it can be classified based on the constituent elements or alloying elements. Aluminium alloy is preferred for the nature of its tensile strength, ductility, and corrosion resistance in this research to make a dissimilar friction stir welding joint of aluminium alloys 7079 and 8050 materials. The tensile strength of the weld joint is estimated by the influence of the response surface methodology approach. The welding is carried out by preferred process parameters with a tool speed of 1000–2500 rpm, tool pin diameter of 2–6 mm, welding speed of 50–300 mm/min, and tool shoulder diameter of 10–20 mm. The ANOVA analysis and the prediction of tensile strength were conducted efficiently. From the RSM analysis, the tool pin diameter mostly modified the output of the result.

Effect of pin diameter and different cooling media on friction stir welding of dissimilar Al-Mg alloys

Abstract Friction Stir welding (FSW) is preferred over conventional welding process for dissimilar materials joining. This is due to controlled heat input which restricts the brittle intermetallic compound (IMC) formation. In the present study, aluminum alloy 6061-T6 and magnesium alloy AZ31B were friction stir welded at the tool rotation speed of 545 rpm, feed speed of 31.5 mm/min, 20 tilt angle and 2 mm offset towards Mg alloy (advancing side) with different tool pin diameter and cooling conditions. Compressed air and CO2 cooling conditions were used to control the heat input. Visual inspection, weld interface, tensile and microhardness measurement were carried out. In-process temperature measurement was carried out for different cooling conditions to relate the heat input. It indicated decreased peak temperature on the advancing side with increased cooling severity. With increasing cooling severity, tensile strength increased to 108.94 MPa. However, microhardness decreased with increased cooling severity due to the possibility of reduced Al/Mg IMC formation.

Effect of different tool pin diameter on mechanical properties of friction stirred welded AISI 304 stainless steel plate

The investigations was carried out to investigate the effect of different friction stir tool pin diameter on mechanical, microstructural properties and welding efficiency of the Stainless Steel AISI 304 friction stir welded specimen. The experiment were carried out at constant tool rotating speed of 1050 rpm, welding speed of 24 mm/min and tools with diameter ranging from 2.5 mm to 4.9 mm at 0.3 mm increasing value. The constant axial force of 10 KN has been applied to perform the friction stir joining. The welded specimens were inspected microscopically and analyzed to obtained mechanical properties such as hardness and UTS, as per the ASTM standard. The maximum tensile strength has been observed as 504 MPa at 2.8 mm tool pin diameter. The maximum welding efficiency of 99% has been observed. The lower tensile strength of the other joints found were due to lower and non-uniform heat distribution at the surface. The microstructure of welded specimen has been analyzed and characterized at different zones by using an optical microscope.

Experimental study and taguchi optimization of process parameter on mechanical properties of A319 aluminum alloy using friction stir welding

The main objective of this abstract is to investigate the effect of welding parameters and the mechanical properties in the study of FSW. In this process, the mathematical model was developed by creating the Taguchi design methodology with three parameters, three levels, and 9 runs and it was also used to develop the relationship between those parameters. It can be produced and using a wide range of process parameters and its recommendation for producing the best joint tensile properties. Taguchi Method is used for the optimization of FSW process parameters for the joining of A319 Aluminum alloys. Taguchi method is signal to noise ratio (S/N) analysis that suggests the maximum tensile strength is reached when rotation, traverse speed, and tool pin diameter were chosen as 900 rpm, 40 mm/ min and 5.5 mm pin diameter respectively. ANOVA is used to find out the importance of the parameters. FSW can produce a satisfactory result of 141.05 MPa tensile strength and 112.04 MPa yield strength. FSW can weld A319 plates with a joint efficiency of around 75%.

The selection of optimum process parameters on A319 aluminum alloy in friction stir welding MCDM method

The main goal of this study is to research optimization process parameters for friction stir welding (FSW). The optimal parameter combinations have better tensile strength with combining decision model. Additive Ratio Assessment (ARAS) method is used to determine the optimum process parameters and suitable it is also for welding operation of Aluminum alloy A319. The friction stir welding parameters is considered for tool rotational speed (rpm), welding feed (mm/min) and tool pin diameter (mm). Taguchi L9 orthogonal array design experiments are mainly used to implement this operation. The Multi-criteria decision model for applying ARAS- method is proposed to solve this problem. The methodology has proved that the offered technology is suitable for finding the multi-criteria optimization for the process parameters in FSW.

Experimental Studies on Friction Stir Processing of Magnesium Alloy

Friction Stir Welding (FSW) belongs to the solid state joining technique. In the present study, the effect of FSW parameters such as rotational speed and tool pin diameter on the weldability of ZK61A Magnesium alloy was investigated and the mechanical and micro structural characteristics of the welded specimens were analyzed at room temperature. Further, the tool wear was estimated with constant shoulder diameter. Radiographic tests were done to identify defects in the weldments.

Optimization of process parameters on friction stir welding of AA7075-T651 and AA6061 joint using response surface methodology

In this research work, dissimilar aluminium alloys of AA7075-T651 and AA6061 were friction stir butt welded by varying the FSW parameters such as tool tilt angle, tool offset and tool pin diameter by using central composite design of response surface methodology (RSM). Experiments were designed by considering three factors and five levels having 20 experimental runs. Ultimate tensile strength and microhardness were employed as responses. Desirability approach has been used to optimize the FSW parameters. Analysis of variance was employed to check the adequacy of the developed model at 95% confidence level. This study revealed that tool pin diameter and tool offset were most significant factors on deciding the tensile strength and microhardness of the joint. It was observed that the joint fabricated with 6 mm pin diameter, 0.9 mm tool offset and 3 degree tilt angle exhibited the maximum tensile strength and microhardness of 267 MPa and 121 Hv when compared to the other joints. Fractography analysis revealed that the FSW joint with maximum tensile strength shows fine dimples which indicates ductile mode of failure.

Monitoring of friction stir welding based on vision system coupled with Machine learning algorithm

The increase in utilization of FSW process demands online monitoring system for early detection and control of defects. This research attempts to develop a system for detection and classification of defective welds using weld surface image. Welding joints are produced at different welding condition by varying tool rotational speed, welding speed, tool shoulder diameter and pin diameter. The weld surfaces produced at different welding condition are captured using digital camera and processed to extract features. The features from weld surface image has been extracted using maximally stable extremal region algorithm and which is used as input for classification of weld joint. The Support Vector Machines is used for classification of weld using features from surface image. Support Vector Machines is trained with different kernel functions and found that linear and quadratic kernel function classify defect weld and good weld with accuracy of 95.8%.

Investigation of Weld Zone obtained by Friction Stir Spot Welding (FSSW) of Aluminium-6061 Alloy

Abstract In the present study, an investigation of the friction stir spot welding (FSSW) of Aluminum 6061 alloy 1 mm thickness sheet has been performed. Radiography images have been used to study the weld properties and the flaws. The study shows the effect of tool rotation speed, dwell time and tool pin diameter on the weld created. Vickers’s micro hardness test results indicate that the micro hardness is highest at stir zone plunge region. This is due to the high compression of the materials taken place at the center of stir zone. Optical microscopic image shows that the pressure created by the rotating tool, forces the material from upper sheet to flow plastically towards the lower sheet and the material is mixed together plastically to form the weld. A finite element model (FEM) has been developed using DEFORM-3D to predict temperature in and near the stir zone. The model indicates that the material remains below the melting temperature and no sign of melting is observed after the FSSW process.

Proposing a new relation for selecting tool pin length in friction stir welding process

In this paper, an empirical relation to determine tool pin length for a specific set of Friction Stir Welding (FSW) parameters such as base material thickness, tool shoulder diameter, tool pin diameter and tool tilt angle is derived and proposed. The effectiveness and suitability of the proposed relation was verified through FSW experiments. Tool pin length was obtained from the relation and FSW of dissimilar aerospace grade aluminium alloys (AA7475 and AA2219) was performed. Three welds were made: one using the FSW tool with the pin length obtained from the proposed relation; second with the pin length smaller and third with the pin length greater than that obtained from the proposed relation. Subsequently, the three welds were compared and it was found that the tool having pin length obtained from the proposed relation resulted in smooth surface morphology and proper material mixing with good consolidation of flowing material at the bottom of the joint. Value of pin length smaller than that obtained from the proposed relation resulted in heavy flash due to larger plunge depth. Value of pin length larger than that obtained from the proposed relation resulted in surface cracks along with insufficient mixing and lack of bonding at the bottom of the joint due to insufficient plunge depth. Joint fabricated with optimized pin was characterized by mechanical testing, microstructure and fractography.