Investigation on the Effects of Process Parameters on Defect Formation in Friction Stir Welded Samples Via Predictive Numerical Modeling and Experiments

2017 ◽  
Vol 139 (11) ◽  
Author(s):  
Abhishek Ajri ◽  
Yung C. Shin
Keyword(s):  
Process Parameters ◽  
Defect Formation ◽  
Weld Strength ◽  
Friction Stir Weld ◽  
Optimum Process ◽  
Fe Model ◽  
Friction Stir ◽  
Different Types ◽  
Induced Flow ◽  
Displacement Based

Setting optimum process parameters is very critical in achieving a sound friction stir weld joint. Understanding the formation of defects and developing techniques to minimize them can help in improving the overall weld strength. The most common defects in friction stir welding (FSW) are tunnel defects, cavities, and excess flash formation, which are caused due to incorrect tool rotational or advancing speed. In this paper, the formation of these defects is explained with the help of an experimentally verified 3D finite element (FE) model. It was observed that the asymmetricity in temperature distribution varies for different types of defects formed during FSW. The location of the defect also changes based on the shoulder induced flow and pin induced flow during FSW. Besides formation of defects like excess flash, cavity defects, tunnel/wormhole defects, two types of groove like defects are also discussed in this paper. By studying the different types of defects formed, a methodology is proposed to recognize these defects and counter them by modifying the process parameters to achieve a sound joint for a displacement-based FSW process.

Investigation on the Effects of Process Parameters on Defect Formation in Friction Stir Welded Samples via Predictive Numerical Modeling and Experiments

2017 ◽  
Author(s):  
Abhishek Ajri ◽  
Yung C. Shin
Keyword(s):  
Friction Stir Welding ◽  
Process Parameters ◽  
Defect Formation ◽  
Welding Process ◽  
Weld Strength ◽  
Friction Stir Weld ◽  
Optimum Process ◽  
Friction Stir ◽  
Different Types ◽  
Induced Flow

Setting optimum process parameters is very critical in achieving a sound friction stir weld joint. Understanding the formation of defects and developing techniques to minimize them can help in improving the overall weld strength. The most common defects in friction stir welding are tunnel defects, cavities and excess flash formation which are caused due to incorrect tool rotational or advancing speed. In this paper, the formation of these defects is explained with the help of an experimentally verified 3D finite element model. It was observed that the asymmetricity in temperature distribution varies for different types of defects formed during friction stir welding. The location of the defect also changes based on the shoulder induced flow and pin induced flow during friction stir welding. Besides formation of defects like excess flash, cavity defects, tunnel/wormhole defects, two types of groove like defects are also discussed in this paper. By studying the different types of defects formed, a methodology is proposed to recognize these defects and counter them by modifying the process parameters to achieve a sound joint for a displacement based friction stir welding process.

scholarly journals Effect of Process Parameters on Defect Features and Mechanical Performance of Friction Stir Lap Welded AA6063 and ETP Copper Joints

2019 ◽  
Vol 8 (2S11) ◽  
pp. 879-883
Keyword(s):  
Process Parameters ◽  
Rotational Speed ◽  
Defect Formation ◽  
Mechanical Performance ◽  
Traverse Speed ◽  
Weld Strength ◽  
Dissimilar Metals ◽  
Tool Rotational Speed ◽  
Friction Stir ◽  
The Difference

The effect of process parameters such as tool rotational speed and tool traverse speed on mechanical properties of AA-6063 and ETP Cu lap joint is investigated. At present, Friction Stir Welding is being employed to join dissimilar metals. However, the difference in the physical properties of the base metals makes it difficult to join these metals. The present study investigates the effect of using a compatible intermediate layer on weld strength. Different joint defects and their effect on joint strength has been discussed. The experiments were conducted with tool rotational speed of 800, 1000 and 1200 rpm each and with tool traverse speeds of 10, 15 and 20 mm/min. The dissimilar metals are successfully lap welded with fair tensile strength. The effect of process parameters on weld strength and defect formation is discussed

Prediction of Surface Profile in Friction Stir Welding Using Coupled Eulerian and Lagrangian Method

2020 ◽  
Author(s):  
Debtanay Das ◽  
Swarup Bag ◽  
Sukhomay Pal ◽  
M. Ruhul Amin
Keyword(s):  
Friction Stir Welding ◽  
Surface Morphology ◽  
Process Parameters ◽  
Chip Formation ◽  
Material Flow ◽  
Defect Formation ◽  
Current Model ◽  
Surface Profile ◽  
Green Technology ◽  
Friction Stir

Abstract Friction stir welding (FSW) is widely accepted by industry because of multiple advantages such as low-temperature process, green technology, and capable of producing good quality weld joints. Extensive research has been conducted to understand the physical process and material flow during FSW. The published works mainly discussed the effects of various process parameters on temperature distribution and microstructure formation. There are few works on the prediction of defect formation from a physics-based model. However, these models ignore chip formation or surface morphology and material loss during the FSW process. In the present work, a fully coupled 3D thermo-mechanical model is developed to predict the chip formation and surface morphology during welding. The effects of various process parameters on surface morphology are also studied using the current model. Coupled Eulerian-Lagrangian (CEL) technique is used to model the FSW process using a commercial software ABAQUS. The model is validated by comparing the results in published literature. The current model is capable of predicting the material flow out of the workpiece and thus enables the visualization of the chip formation. The developed model can extensively be used to predict the surface quality of the friction stir welded joints.

Optimization of Friction Stir Welding Process Parameters to Join Al 5052 and Al 6061 Alloy Plates Using Grey-Taguchi Technique

2017 ◽  
Author(s):  
R. Sandeep ◽  
D. Sudhakara ◽  
G. Prasanthi
Keyword(s):  
Friction Stir Welding ◽  
Process Parameters ◽  
Welding Process ◽  
Dissimilar Materials ◽  
Fusion Welding ◽  
Optimum Process ◽  
Friction Stir ◽  
Friction Stir Welding Process ◽  
Grey Analysis ◽  
Grey Taguchi

Friction stir welding (FSW) is a solid state welding process used for welding similar and dissimilar materials. The process is widely used because it does not have common problems such as solidification and liquefaction cracking associated with the fusion welding techniques. The objective of the present research is to find the best combination of friction stir welding process parameters to join aluminium 5052 and 6061 alloy materials. The combination of process parameters is helpful to improve ultimate tensile strength, yield strength, percentage of elongation and hardness of welded joint. To achieve the research objective taguchi based grey analysis was used. The optimum process parameters were found be at rotational speed is 1400 rpm, transverse speed of 100 mm/min and axial force is at 11 KN.

Effect of Process Parameters on Defect Formation in Friction Stir Processed 6082-T6 Aluminium Alloy

2012 ◽  
Vol 232 ◽  
pp. 3-7
Author(s):  
Akinlabi Esther Titilayo ◽  
Akinlabi Stephen Akinwale
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Aluminium Alloy ◽  
Process Parameters ◽  
Friction Stir Processing ◽  
Feed Rate ◽  
Rotational Speed ◽  
Defect Formation ◽  
Processing Parameters ◽  
Friction Stir

This paper reports the effects of processing parameters on defects formed during friction stir processing of 6082-T6 Aluminium Alloy. The plates were processed by varying the feed rate between 50 and 250 mm/min, while the rotational speed was varied between 1500 and 3500 rpm to achieve the best result. It was observed that the sheets processed at the highest feed rate considered in this research resulted in wormhole defect. These processed samples with defects were correlated to the tensile results and it was found that the Ultimate Tensile Strength (UTS) of these samples was relatively low compared to other samples without defects.

scholarly journals Parametric Optimization of Friction Stir Welding Factors (FSWF) for Yellow Brass 405-20

2021 ◽  
Author(s):  
Syed Farhan Raza ◽  
Sarmad Ali Khan ◽  
Muhammad Salman Habib ◽  
Naveed Ahmed ◽  
Kashif Ishfaq ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Rotational Speed ◽  
Weld Zone ◽  
Tool Material ◽  
Traverse Speed ◽  
Weld Strength ◽  
Friction Stir Weld ◽  
Friction Stir ◽  
Wide Range ◽  
Percent Contribution

Abstract Friction stir welding (FSW) is a green, environmentally amicable, and solid-state joining technology. Industries are really interested in adopting FSW in its various applications e.g., automobile, aerospace, marine, construction, etc. FSW can successfully weld a wide range of materials (similar/dissimilar parent materials) including aluminum, copper, steel, different alloys from these materials, plastics, composites, and this material range is subjected to extension if FSW research efforts develop further in future. FSW of brass has already been accomplished by fewer researchers. In this research, yellow brass 405-20 is, therefore, welded with FSW that was never welded before. In this study, tool material utilized was M2 HSS that was also novel. Effect of two friction stir weld factors (FSWF), rotational speed (RS) and traverse speed (TS), was found on three output parameters i.e., weld temperature, weld strength and weld hardness. Weld temperature was found to be 63.72% of melting point of base metal. A significant improvement in friction stir weld strength (FSWS) was also measured that was found to be 82.78% of the base brass strength. Finally, weld hardness was measured which was found to be 87.80% of original brass hardness. Based on main effects of Anova Analysis, optimal FSW factors were found to be 1450 rpm and 60 mm/min resulting interestingly in maximum (max.)/optimal temperature, max./optimal weld strength, and minimum/optimal hardness. Rotational speed (RS) was found to be significant to affect the weld temperature only at the friction stir weld zone (FSWZ) with the highest percent contribution (PCR) of 65.69%. Transverse speed (TS) was found to be overall insignificant for affecting weld temperature, weld strength and hardness. However, PCR of transverse speed was found to be maximum for affecting weld strength as compared to its PCR towards both weld temperature and weld hardness. Error PCR was found to be the lowest for weld zone temperature, then for weld strength, and finally the highest for weld hardness. Interaction Plots (IPs) were also made for those FSWF which were found to be insignificant and to investigate any combined effect of FSWF on output parameters causing increased error PCR towards weld temperature, weld strength, and weld hardness.

scholarly journals Research the Effect of Process Parameters on Friction Stir Welded AA6063-ETP Copper joint using Taguchi Technique

2019 ◽  
Vol 8 (2S11) ◽  
pp. 884-888
Keyword(s):  
Thermal Conductivity ◽  
Process Parameters ◽  
Rotational Speed ◽  
Traverse Speed ◽  
Copper Plate ◽  
Heat Sinks ◽  
Optimum Process ◽  
Tool Rotational Speed ◽  
Alloy Plate ◽  
Friction Stir

Aluminium and copper, or their combination finds application in heat sinks because of their excellent thermal conductivity. In the present study, Al–6063 and ETP copper were lap welded using friction stir welding wherein the aluminum alloy plate was placed on top of the copper plate. The optimum process parameters were found using Taguchi L9 orthogonal array. The process parameters namely tool rotational speed, tool traverse speed and thickness of zinc inter-filler material were considered. The optimal process parameters were ascertained with respect to the thermal conductivity of weld. The predicted optimum value of thermal conductivity was verified by conducting the confirmation run using the optimal parameters. Analysis of variance depicted that all the three process parameters were significant, wherein the tool rotational speed and the tool traverse speed were the most dominant factors contributing to thermal conductivity.

scholarly journals Forming and Properties of Friction Stir Welding Process for Dissimilar Mg Alloy

2015 ◽  
Vol 9 (1) ◽  
pp. 859-864
Author(s):  
Tielong Li ◽  
Zhenshan Wang
Keyword(s):  
Magnesium Alloy ◽  
Process Parameters ◽  
Welded Joints ◽  
Defect Formation ◽  
Base Material ◽  
Welding Process ◽  
Fracture Initiation ◽  
Line Defect ◽  
Influence Of Process Parameters ◽  
Friction Stir

For hot extrusions of magnesium alloy sheets, Dissimilar AZ80 and AZ31 were used, in which AZ80 was placed on advancing side and AZ31 on retreating side, using friction stir butt welding with different process parameters. Some defect-free welded joints with good weld surfaces could be obtained with some suitable welding conditions. The maximum tensile strength of welded joint which is 225.5 MPa can reach 98% that of the AZ31 base material. Influence of process parameters on defects, weld shaping and mechanical property were discussed systematically. And the microstructure of different zones was compared. The fracture of the welded joints takes place at the junction of mechanical heat affected zone and nugget zone in AZ31 magnesium alloy set retreating side, since existing difference in metallographic structure of alloy diversely suffered by heat, pressure and depositing impurities. Fracture initiation site may be the P line defect which should be eliminated, and the P line defect formation was analyzed.

Utilization of a Curly Toolpath in Friction Stir Welding

2021 ◽  
Vol 1165 ◽  
pp. 15-29
Author(s):  
Tyler J. Grimm ◽  
Derek Shaffer ◽  
Ihab Ragai
Keyword(s):  
Friction Stir Welding ◽  
Process Parameters ◽  
Tool Path ◽  
Base Material ◽  
The Other ◽  
Weld Strength ◽  
Mechanical Mixing ◽  
Material Interface ◽  
Friction Stir ◽  
High Level

Friction stir welding (FSW) is an advanced solid-state metal joining technique. This operation fuses adjacent materials through the use of a non-consumable, rotating tool, which is plunged into and travels along the seam of the materials. Since this joining method avoids the bulk melting of the base materials, it is considered a relatively energy efficient process. Additionally, the strength of the base material is often improved due to significant grain refinement resulting from the stirring action of the tool at relatively low temperatures. Another inherent benefit is that the joint thickness, which is dependent on the length of the pin, can be much greater than most other joining processes and can also be well controlled. This joining method conventionally relies on the friction at the tool-base material interface to stir materials. Other research has implemented complex tooling to mechanically enhance this stirring action. However, these tools are often expensive, requiring a high level of capability within industry. In order to improve the weld strength of FSW, a novel toolpath is utilized which significantly improves the mechanical mixing of the constituent materials without the need for complex tooling, such as tools with threaded pins. The path currently investigated forms a curl as it travels both perpendicular and parallel to the joint. This motion is used to extend the stirring action of the tool to regions outside the immediate joint area. It was found that this tool path is effective in improving weld strength under specific process parameters. Constraining the tool's axis normal to the workpiece surface resulted in a void that was formed in the majority of tests; however, this void was eliminated with modification of the process parameters. An uneven distribution of heat was recognized within this testing in which one side of the joint was hotter than the other. This observation may be used in future studies to perform multi-material joining where it is often necessary to increase the temperature of one material more than the other.

scholarly journals Optimization of FSW parameters for maximum UTS of AA6082/SiC/10P composites

2019 ◽  
Vol 28 ◽  
pp. 096369351986770 ◽  
Author(s):  
Rajesh Kumar Bhushan ◽  
Deepak Sharma
Keyword(s):  
Tensile Strength ◽  
Process Parameters ◽  
Signal To Noise Ratio ◽  
Composite Plates ◽  
Optimum Process ◽  
Friction Stir ◽  
Tool Tilt Angle ◽  
Experimental Values ◽  
Fsw Parameters ◽  
Tool Rotation

Friction stir welding (FSW) offers significant advantage when compared with fusion joining process such as no shield gas or flux are used, no harmful gases are produced, thereby making the FSW environmentally friendly. In this work, an experimental approach has been used for studying and optimizing the FSW process, applied on AA6082/SiC/10P composite plates. In particular, the effect of process parameters on ultimate tensile strength (UTS) of FSW joint has been investigated. The UTS of FSW joints is affected by FSW parameters. The FSW of the AA6082/SiC/10P composite plates was carried out with different combinations of FSW parameters. The experiments were conducted according to the Taguchi’s L9 orthogonal array. Taguchi method of designing the experiments was used for optimization of the FSW parameters. The signal to noise ratio and analysis of variance were used to determine the effects of FSW parameters on the UTS of the welded joints. The optimum FSW parameters for the maximum UTS were found to be the tool rotation speed of 1800 r/min, the welding speed of 100 mm/min and the tool tilt angle of 2°. UTS increased by 24.5% when FSW was carried out at optimum process parameters as compared to initial FSW parameters. Results have shown good agreement between the predicted and experimental values of UTS. High tensile strength is required for use of FSWed AA6082/SiC/10P composite joints in aerospace industry.

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