scholarly journals Controlling residual stress and distortion of friction stir welding joint by external stationary shoulder

2019 ◽  
Vol 38 (2019) ◽  
pp. 662-671 ◽  
Author(s):  
Weiliang He ◽  
Jinglin Liu ◽  
Wei Hu ◽  
Gongdong Wang ◽  
Wenjing Chen
Keyword(s):  
Residual Stress ◽  
Friction Stir Welding ◽  
Mechanical Model ◽  
Residual Stress Distribution ◽  
Butt Weld ◽  
Friction Stir ◽  
Welding Joint ◽  
Stationary Shoulder ◽  
Stress Region ◽  
Synchronous Rolling

AbstractFriction stir welding (FSW) can achieve a sound welding joint, but its residual stress and distortion cannot be avoided due to the non-uniformity of temperature distribution during welding. Stationary shoulder friction stir welding (SSFSW) was employed to butt weld 6005A-T6 aluminum alloy plates. The effects of welding speeds ranging from 200 mm/min to 600 mm/min on residual stress and distortion were investigated in detail. A thermo-mechanical model was utilized to compare the residual stress distribution between conventional FSW and SSFSW. SSFSW was beneficial to decreasing the peak temperature of stir zone (SZ) and then obtaining a narrower SZ. The peak residual stress produced by SSFSW was 50% lower than that by conventional FSW and a narrower tensile stress region was attained by SSFSW. Moreover, the stationary shoulder applied a function of synchronous rolling during the welding, which controlled the distortion effectively.

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.

Comparison of Residual Stress Between MIG Welding and Friction Stir Welding

2012 ◽  
Vol 155-156 ◽  
pp. 1218-1222
Author(s):  
Lei Wang ◽  
Mitsuyosi Tsunori
Keyword(s):  
Residual Stress ◽  
Friction Stir Welding ◽  
Stress Distribution ◽  
Yield Strength ◽  
Room Temperature ◽  
Welding Process ◽  
Residual Stress Distribution ◽  
Mig Welding ◽  
Friction Stir ◽  
Friction Stir Welding Process

Residual stress distribution plays a very important role in welded structures, the aim of present work is to find out the effect of different welding methods on the residual stress distribution by means of neutron diffraction measurements and FE models simulation. 4 mm thick DH-36 steel plates were butt welded by MIG welding process and 5 mm thick AA 2024 aluminium alloy plates were butt welded by friction stir welding process. Results show that residual stresses of MIG welding process are higher than those of friction stir welding process. The peak residual stress of MIG weld is close to the room temperature uniaxial yield strength of DH-36 while the peak residual stress of friction stir weld is just about 50% of the room temperature uniaxial yield strength of AA2024. The size effect of MIG welded and effect of welding speeds of friction stir welded on the residual stress distribution have also been studied in the paper.

scholarly journals The Contour Method for Residual Stress Determination Applied to an AA6082-T6 Friction Stir Butt Weld

2011 ◽  
Vol 681 ◽  
pp. 177-181 ◽  
Author(s):  
Valentin Richter-Trummer ◽  
Pedro Miguel Guimarães Pires Moreira ◽  
João Ribeiro ◽  
Paulo Manuel Salgado Tavares de Castro
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Cross Section ◽  
Residual Stress Distribution ◽  
Contour Method ◽  
Friction Stir Weld ◽  
Hole Drilling ◽  
Butt Weld ◽  
Friction Stir

Residual stresses parallel to the welding direction on a cross-section of a 3 mm thick friction stir butt-welded aluminum alloy AA6082-T6 plate were determined using the contour method. A full contour map of longitudinal residual stresses on a weld cross section was determined in this way, revealing detailed information on the residual stress distribution in the inside of a friction stir weld, especially in the nugget zone. The typical M-shape, usually described for the residual stress distribution in friction stir welds, was found. The maximum residual stresses are below the yield strength of the material in the shoulder region and, outside of the welding region, low tensile and compressive residual stresses are responsible for the necessary stress equilibrium on the plane of interest. A comparison was made with the established incremental hole drilling technique on an equivalent plate for validation and good agreement of both techniques was obtained. The distribution, as well as the magnitude of the residual stresses measured by both techniques, is very similar, thus validating both the experimental and numerical procedures used for the contour method application, presented and discussed in the present paper.

Integrated Design and Numerical Simulation of Stiffened Panels Including Friction Stir Welding Effects

2013 ◽  
Vol 554-557 ◽  
pp. 2237-2242 ◽  
Author(s):  
Rui Miguel Ferreira Paulo ◽  
Pierpaolo Carlone ◽  
Robertt A.F. Valente ◽  
Filipe Teixeira-Dias ◽  
Gaetano S. Palazzo
Keyword(s):  
Numerical Simulation ◽  
Residual Stress ◽  
Friction Stir Welding ◽  
Stress Distribution ◽  
Residual Stresses ◽  
Ultimate Load ◽  
Simulation Models ◽  
Residual Stress Distribution ◽  
Stiffened Panels ◽  
Friction Stir

Stiffened panels are usually the basic structural building blocks of airplanes, vessels and other structures with high requirements of strength-to-weight ratio. They typically consist of a plate with equally spaced longitudinal stiffeners on one side, often with intermediate transverse stiffeners. Large aeronautical and naval parts are primarily designed based on their longitudinal compressive strength. The structural stability of such thin-walled structures, when subjected to compressive loads, is highly dependent on the buckling strength of the structure as a whole and of each structural member. In the present work, a number of modelling and numerical calculations, based on the Finite Element Method (FEM), is carried out in order to predict the ultimate load level when stiffened panels are subjected to compressive solicitations. The simulation models account not only for the elasto-plastic nonlinear behaviour, but also for the residual stresses, material properties modifications and geometrical distortions that arise from Friction Stir Welding (FSW) operations. To construct the model considering residual stresses, their distribution in FSW butt joints are obtained by means of a numerical-experimental procedure, namely the contour method, which allows for the evaluation of the normal residual stress distribution on a specimen section. FSW samples have been sectioned orthogonally to the welding line by wire electrical discharge machining (WEDM). Displacements of the relaxed surfaces are then recorded using a Coordinate Measuring Machine and processed in a MATLAB environment. Finally, the residual stress distribution is evaluated by means of an elastic FE model of the cut sample, using the measured and digitalized out-of-plane displacements as input nodal boundary conditions. With these considerations, the main goal of the present work will then be related to the evaluation of the effect of FSW operations, in the ultimate load of stiffened panels with complex cross-section shapes, by means of realist numerical simulation models.

Residual Stress Measurement in Innovative Friction Stir Welding Processes

2017 ◽  
Vol 754 ◽  
pp. 391-394
Author(s):  
D. Campanella ◽  
C. Casavola ◽  
A. Cazzato ◽  
Livan Fratini ◽  
V. Moramarco ◽  
...  
Keyword(s):  
Residual Stress ◽  
Corrosion Resistance ◽  
Friction Stir Welding ◽  
Material Properties ◽  
Stress Measurement ◽  
Residual Stress Distribution ◽  
Butt Joints ◽  
Welded Structures ◽  
Friction Stir ◽  
Welding Processes

In recent years, important innovations have been introduced in Friction Stir Welding (FSW) technology such as, for example, the Laser assisted Friction Stir Welding (LFSW) and in-process Cooled Friction Stir Welding (CFSW). Residual stresses have a fundamental role in welded structures because they affect the way to design the structures, fatigue life, corrosion resistance and many other material properties. Consequently, it is important to investigate the residual stress distribution in FSW where, though the heat input is lower compared to traditional welding techniques, the constraints applied to the parts to weld are more severe. The aim of the present work is to verify the capabilities of both FSW techniques in reduction of the residual stress in aluminium butt joints.

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