Residual stress, tensile strength, and macrostructure investigations on ultrasonic assisted friction stir welding of AA 6061-T6

2018 ◽  
Vol 53 (7) ◽  
pp. 494-503 ◽  
Author(s):  
Iman Alinaghian ◽  
Saeid Amini ◽  
Mohammad Honarpisheh
Keyword(s):  
Residual Stress ◽  
Tensile Strength ◽  
Friction Stir Welding ◽  
Weld Zone ◽  
Ultrasonic Power ◽  
Ultrasonic Vibrations ◽  
Friction Stir ◽  
Longitudinal Residual Stress ◽  
Ultrasonic Assisted

In recent decades, ultrasonic vibrations are used in manufacturing processes because they can improve tool life, material performance, and quality. One of them which can be integrated with ultrasonic vibrations is friction stir welding called ultrasonic assisted friction stir welding. In previous studies, the effect of ultrasonic vibrations on the mechanical, metallurgical, and thermal properties was investigated and there is not any residual stress investigations on ultrasonic assisted friction stir welding. Since residual stress plays an important role in performance and stability of components, the influence of ultrasonic power on the longitudinal residual stress in friction stir welding is investigated in this work. In spite of residual stress, tensile strength and quality of weldment were investigated as complementary terms to ensure successful performance of ultrasonic assisted friction stir welding. The findings indicated that high-frequency vibrations with power of 200 W can reduce the maximum tensile residual stress about 45% and significantly increase tensile strength. Also, ultrasonic vibrations prevent defect such has voids and tunnel in weld zone due to peening effect in ultrasonic assisted friction stir welding.

Numerical Simulation of Plunge Force During the Plunge Phase of Friction Stir Welding and Ultrasonic Assisted FSW

2008 ◽  
Author(s):  
Kwanghyun Park ◽  
Bongsuk Kim ◽  
Jun Ni
Keyword(s):  
Numerical Simulation ◽  
Friction Stir Welding ◽  
High Frequency ◽  
Hybrid Welding ◽  
Ultrasonic Vibrations ◽  
Welding Quality ◽  
Friction Stir ◽  
Ultrasonic Assisted ◽  
Welding Force ◽  
Welding Technique

Ultrasonic assisted friction stir welding (UaFSW) is an hybrid welding technique, where high frequency vibration is superimposed on the movement of a rotating tool. The benefit of using ultrasonic vibration in the FSW process refers to the reduction in the welding force and to the better welding quality. The UaFSW system is being developed and its mechanism needs to be understood using both the experiments and the numerical simulations. In this paper, FE simulations of FSW and UaFSW using ABAQUS/Explicit were carried out to examine plunge forces during the plunge phase of FSW and UaFSW, respectively. First, the simulations of the conventional FSW process were validated. Then, simulation of UaFSW process was performed by imposing sinusoidal horizontal ultrasonic vibrations on the tool.

Process - Property Correlation of Friction Stir Welding of Marine Grade Aluminium Alloy 5083 Using Finite Element Analysis

2021 ◽  
Vol 163 (A2) ◽  
Author(s):  
M Sahu ◽  
A Paul ◽  
S Ganguly
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Finite Element ◽  
Friction Stir Welding ◽  
Residual Stresses ◽  
Process Variables ◽  
Friction Stir ◽  
Stress Region ◽  
Longitudinal Residual Stress ◽  
Process Property

In this article, a 3D finite element based thermo-mechanical model for friction stir welding (FSW) of a marine-grade aluminium alloy 5083 is proposed. The model demonstrates the thermal evaluation and the distribution of residual stresses and strains under the variation of process variables. The temperature profile of the weld joint during the FSW process and the mechanical properties of the joints are also experimentally evaluated. The necessary calibration of the model for the correct implementation of the thermal loading, mechanical loading, and boundary conditions was performed using the experimental results. The model simulation and experimental results are analyses in view of the process-property correlation study. The residual stress was evaluated along, and across the weld, centreline referred as longitudinal and transverse residual stresses, respectively. The magnitude of longitudinal residual stress is noted 60-80% higher than that of the transverse direction. The longitudinal residual stress generated a tensile oval shaped stress region around the tool shoulder confined to a maximum distance of about 25mm from the axis of the tool along the weld line. It encompasses the weld-nugget to thermo-mechanically affected zone (TMAZ), while the parent metal region is mostly experiences the compressive residual stresses. However, the transverse residual stress region appears like wing shaped region spread out in both the advancing and retreating side of the weld and occupying approximately double the area as compared to the longitudinal residual stresses. Overall, the study revealed a corelation between the FSW process variables such as welding speed and the tool rotational speed with the residual stress and the mechanical properties of the joint.

Numerical Simulations of Friction Stir Welding Process and Subsequent Post Weld Cold Rolling Process

2009 ◽  
Vol 419-420 ◽  
pp. 433-436 ◽  
Author(s):  
Yu Jie Sun ◽  
Yong Zang ◽  
Qing Yu Shi
Keyword(s):  
Residual Stress ◽  
Friction Stir Welding ◽  
Three Dimensional ◽  
Welding Process ◽  
Rolling Process ◽  
Mechanical Analysis ◽  
Fusion Welding ◽  
Work Piece ◽  
Friction Stir ◽  
Longitudinal Residual Stress

A sequential coupled three-dimensional thermo-mechanical analysis was conducted first to simulate friction stir welding (FSW) of aluminum alloy. In thermal analysis, the model included adaptive heat source, contact heat transfer both between work piece and clamps and between work piece and backing board etc; in the mechanical analysis, the model involved contact interaction both between work piece and clamps and between work piece and backing board, mechanical load of tool etc. The simulation results indicate that the longitudinal residual stress is unsymmetrical about weld centerline; the magnitude of longitudinal residual stress for FSW process is lower than that for fusion welding process. Based on simulated results of FSW process, a three-dimensional elastic-plastic analysis was then carried out to simulate rolling process, the simulation result show that rolling process not only causes a marked reduction in the longitudinal tensile residual but also reverse the sign of the longitudinal residual stress.

scholarly journals Characterization of Brass/Steel Plates Joined by Friction Stir Welding

2018 ◽  
Vol 7 (3.34) ◽  
pp. 366
Author(s):  
Mariyappan. K ◽  
Praveen K ◽  
Suresh Kumar.S ◽  
Kadambanathan. K ◽  
Rajamanickam. S ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Friction Stir Welding ◽  
Weld Zone ◽  
Steel Plates ◽  
Micro Hardness ◽  
Friction Stir ◽  
Fsw Parameters ◽  
Scanning Electron

The aim of this study is to show the feasibility for butt joining dissimilar brass to austenitic stainless steel plates by Friction Stir Welding. In this study, the limited FSW parameters were employed. Metallurgical characterization like Scanning Electron Microscopy and Mechanical characterization like tensile test, Micro hardness is done to investigate the joint performance and the weld zone of dissimilar brass/steel joints. The tensile strength and micro hardness values are 20 MPa, 122 MPa and 157 MPa and 175 Hv, 196 Hv and 199 Hv for the table traverse speeds of 40 mm/min, 50 mm/min and 60 mm/min respectively. The tensile strength of dissimilar brass/steel joint was found to be lower than that of parent metals. The defect free brass/steel interfaces were seen by Scanning Electron Microscopy. It was illustrated that the stirred zone exposed to two main structures namely, recrystallized grains of brass and intercalated swirl and vortex-like structure which can be characterized both the recrystallized brass grains and steel layers. This work is one of the preliminary studies on the detailed examinations of the dissimilar brass/steel joined by Friction stir welding. 

scholarly journals Improvement on Mechanical Properties of Submerged Friction Stir Joining of Dissimilar Tailor Welded Aluminum Blanks

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
R. Suryanarayanan ◽  
V. G. Sridhar ◽  
L. Natrayan ◽  
S. Kaliappan ◽  
Anjibabu Merneedi ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Friction Stir Welding ◽  
Mechanical Performance ◽  
Weld Zone ◽  
Tensile Tests ◽  
Welding Parameters ◽  
Negative Effects ◽  
Friction Stir ◽  
Tailor Welded Blanks ◽  
Secondary Precipitates

Friction stir welding is a solid-state welding method that produces joints with superior mechanical and metallurgical properties. However, the negative effects of the thermal cycle during welding dent the mechanical performance of the weld joint. Hence, in this research study, the joining of aluminum tailor welded blanks by friction stir welding is carried out in underwater conditions by varying the welding parameters. The tensile tests revealed that the underwater welded samples showed better results when compared to the air welded samples. Maximum tensile strength of 229.83 MPa was obtained at 1000 rpm, 36 mm/min. The improved tensile strength of the underwater welded samples was credited to the suppression of the precipitation of the secondary precipitates due to the cooling action provided by the water. The lowest hardness of 72 HV was obtained at the edge of the stir zone which indicated the weakest region in the weld zone.

Vertical Compensation Friction Stir Welding of 6061-T6 Aluminum Alloy

2016 ◽  
Vol 35 (8) ◽  
pp. 843-851 ◽  
Author(s):  
Shude Ji ◽  
Xiangchen Meng ◽  
Jingwei Xing ◽  
Lin Ma ◽  
Shuangsheng Gao
Keyword(s):  
Adverse Effect ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Welding Speed ◽  
Rotational Velocity ◽  
Weld Zone ◽  
Strengthening Effect ◽  
Fracture Surface Morphology ◽  
Friction Stir

AbstractVertical compensation friction stir welding (VCFSW) was proposed in order to solve the adverse effect caused by a big gap at the interface between two welded workpieces. VCFSW was successfully applied to weld 6061-T6 aluminum alloy with the thickness of 4 mm, while 2024-T4 aluminum alloy was selected as a rational compensation material. The results show that VCFSW is difficult to get a sound joint when the width of strip is no less than 1.5 mm. Decreasing the welding speed is beneficial to break compensation strip into pieces and then get higher quality joint. When the width of strip is 1 mm, the tensile strength and elongation of joint at the welding speed of 50 mm/min and rotational velocity of 1,800 rpm reach the maximum values of 203 MPa and 5.2%, respectively. Moreover, the addition of 2024-T4 alloy plays a strengthening effect on weld zone (WZ) of VCFSW joint. The fracture surface morphology of joint consisting of amounts of dimples exhibits ductile fracture.

Study of Nonuniform In-Plane and In-Depth Residual Stress of Friction Stir Welding

2003 ◽  
Vol 125 (2) ◽  
pp. 201-208 ◽  
Author(s):  
Min Ya ◽  
Fulong Dai ◽  
Jian Lu
Keyword(s):  
Residual Stress ◽  
Friction Stir Welding ◽  
Stress Gradient ◽  
High Stress ◽  
Hole Drilling ◽  
Friction Stir ◽  
Hole Drilling Method ◽  
Incremental Hole Drilling ◽  
Longitudinal Residual Stress ◽  
Drilling Method

Friction stir welding (FSW) is a newly developed welding technique that can join aluminum alloys of low fusion weldability. The conventional hole-drilling method does not consider the nonuniform in-plane stress around the drilled hole, it is no longer valid for the residual stress of FSW which has high stress gradient. However, assuming the relaxation of in-plane nonuniform residual stress to be uniform on a small increment of the boundary of the hole, the recently developed Moire´ interferometry incremental hole-drilling (MIIHD) method can be used. Residual stress of a thin plate of friction stir welded aluminum alloy was studied by MIIHD. The longitudinal residual stress distribution in the transversal direction and through the thickness was obtained and compared with results by strain gage method.

scholarly journals Repair Welding of the Tunnel Defect in Friction Stir Weld

2018 ◽  
Vol 37 (7) ◽  
pp. 675-681 ◽  
Author(s):  
Weipo Li ◽  
Zhimin Liang ◽  
Congwei Cai ◽  
Dianlong Wang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Yield Strength ◽  
Weld Zone ◽  
Welding Process ◽  
Friction Stir Weld ◽  
Strength Increase ◽  
Repair Welding ◽  
Friction Stir ◽  
Longitudinal Residual Stress

AbstractThe tunnel defect formed in friction stir weld would dramatically push the mechanical properties of joints into deterioration. In this study, friction stir welding process was adopted to repair the joints of 7N01 aluminum alloy with tunnel defect. The effects of friction stir repair welding process on the microstructure and mechanical properties were comprehensively investigated. Microstructure of the repaired joints shows that the grain size in nugget zone decreases slightly while the recrystallization in the retreating side of thermo-mechanically affected zone is intensified as the joints are repaired. The microhardness of the repaired joints declined slightly compared with the defective joint. However, the yield strength and tensile strength increase and recover to the values of the joints free of defect. The longitudinal residual stress in weld zone increased remarkably as the repair times increase. Compared with the once repaired joint, yield strength and tensile strength of the twice repaired joint reduced slightly, and the throat thickness also reduced during the repeated repair welding process. Therefore, the times of repair welding applied should be limited actually.

Effect of Ultrasonic Application during Friction Stir Welding on Microstructure and Properties of AA2024 Fixed Joints

2016 ◽  
Vol 683 ◽  
pp. 227-231 ◽  
Author(s):  
Alexander A. Eliseev ◽  
Sergei Yu. Tarasov ◽  
Sergey Fortuna ◽  
Valery E. Rubtsov ◽  
Tatiana Kalashnikova
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Friction Stir Welding ◽  
Ultrasonic Vibration ◽  
Friction Stir ◽  
Vibration Effect ◽  
Ultrasonic Assisted ◽  
Aluminum Alloy 2024 ◽  
Joint Quality

Microstructure and mechanical properties of aluminum alloy 2024 fixed joint produced by ultrasonic assisted friction stir welding are described. Tensile strength, microhardness, grain size and zone area are measured and compared with ones of joint produced without ultrasonic vibration. Analyzing this data authors make conclusion about ultrasonic vibration effect on friction stir welding joint quality.

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