Numerical Investigation on Dissimilar Friction Stir Welding of Aluminum and Magnesium Sheets

2014 ◽  
Vol 622-623 ◽  
pp. 532-539 ◽  
Author(s):  
Gianluca Buffa
Keyword(s):  
Friction Stir Welding ◽  
Solid State ◽  
Material Flow ◽  
Welding Process ◽  
Correct Choice ◽  
Mutual Position ◽  
Main Field ◽  
Butt Joints ◽  
Friction Stir ◽  
Dissimilar Friction Stir Welding

Friction Stir Welding (FSW) is a solid-state welding process used to weld difficult to be welded or unweldable materials as aluminum alloys. In the last years other materials have been successfully tested as magnesium, titanium and nickel based alloys. Mixed joints can be obtained by FSW but issues arise in the correct choice of the process parameters. In the paper a numerical model is presented for the prediction of the main field variables distribution and the occurring material flow in FSW of dissimilar AA6061 and AZ31 butt joints. Important insights are obtained on the effect of the mutual position of the two materials with respect to the advancing and retreating side of the joint has been highlighted.

Numerical Analysis of In-Process Heat Transfer and Material Flow During Dissimilar Friction Stir Welding Process

2019 ◽  
Author(s):  
Gaoqiang Chen ◽  
Xun Liu ◽  
Qingyu Shi
Keyword(s):  
Heat Transfer ◽  
Friction Stir Welding ◽  
Material Flow ◽  
Welding Process ◽  
Dissimilar Materials ◽  
Friction Stir ◽  
Coupling Behavior ◽  
Dissimilar Friction Stir Welding ◽  
Computational Fluid Dynamics Cfd ◽  
Process Heat

Abstract Friction stir welding (FSW) has been successfully applied to join dissimilar materials in engineering applications. Fundamental understanding on the underlying physical principles of the dissimilar FSW process is generally required to achieve strong and reliable joints. In this study, we aim to develop a theoretical and numerical model based on computational fluid dynamics (CFD) in order to analyze the in-process heat transfer and material flow during the dissimilar FSW of aluminum and steel. The model describes the coupling behavior between the material distribution, thermal-mechanical properties, interfacial friction, heat generation and transfer. To account for the different material behaviors in stirring zone, a VOF-based approach is adopted. In this paper, preliminary numerical simulation is conducted. Simulation results show that the current modeling approach has the capability to capture the material mixing during the dissimilar FSW of aluminum and steel. The predicted temperature field is shown to be asymmetrical, which is attributed to the different properties of aluminum and steel. The predicted thermal history agrees with the experimental measurements in the literature.

Thermo-Mechanical Modelling of Friction Stir Welding Process

2013 ◽  
Vol 774-776 ◽  
pp. 1155-1159 ◽  
Author(s):  
Xiao Cong He
Keyword(s):  
Finite Element Analysis ◽  
Friction Stir Welding ◽  
Mechanical Behaviour ◽  
Material Flow ◽  
Welding Process ◽  
Element Analysis ◽  
Friction Stir ◽  
Mechanical Modelling ◽  
Major Factors ◽  
Realistic Prediction

Friction stir welding (FSW) is a solid-state welding process where no gross melting of the material being welded takes place. Numerical modelling of the FSW process can provide realistic prediction of the thermo-mechanical behaviour of the process. Latest literature relating to finite element analysis (FEA) of thermo-mechanical behaviour of FSW process is reviewed in this paper. The recent development in thermo-mechanical modelling of FSW process is described with particular reference to two major factors that influence the performance of FSW joints: material flow and temperature distribution. The main thermo-mechanical modelling used in FSW process are discussed and illustrated with brief case studies from the literature.

A Finite Element Model for the Prediction of Chip Formation and Surface Morphology in Friction Stir Welding Process

2021 ◽  
pp. 1-21
Author(s):  
Debtanay Das ◽  
Swarup Bag ◽  
Sukhomay Pal ◽  
M. Ruhul Amin
Keyword(s):  
Finite Element ◽  
Friction Stir Welding ◽  
Surface Morphology ◽  
Chip Formation ◽  
Material Flow ◽  
Welding Process ◽  
Measured Temperature ◽  
Material Loss ◽  
Friction Stir ◽  
Mass Scaling

Abstract Friction stir welding (FSW) is widely recognized green manufacturing process capable of producing good quality welded joints at temperature lower than the melting point. However, most of the works is focused on to the establishment of the process parameters for a defect-free joint. There is a lack to understand the formation of defects from physical basis and visualization of the same, which is otherwise difficult to predict by means of simple experiments. The conventional models do not predict chip formation and surface morphology by accounting the material loss during the process. Hence, a 3D finite element based thermo-mechanical model is developed following Coupled Eulerian-Lagrangian (CEL) approach to understand surface morphology by triggering material flow associated with tool-material interaction. In the present quasi-static analysis, the mass scaling factor is explored to make the model computationally feasible by varying the FSW parameter of plunge depth. The simulated results are validated with experimentally measured temperature and surface morphology. In CEL approach, the material flow out of the workpiece enables the visualization of the chip formation, whereas small deformation predict the surface quality of the joint.

scholarly journals Internal Material Flow Layers in AA6082-T6 Butt-Joints during Bobbin Friction Stir Welding

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1059 ◽  
Author(s):  
Tamadon ◽  
Pons ◽  
Clucas ◽  
Sued
Keyword(s):  
Friction Stir Welding ◽  
Grain Boundaries ◽  
Material Flow ◽  
Internal Flow ◽  
High Density ◽  
Butt Joints ◽  
Friction Stir ◽  
Discontinuous Flow ◽  
Flow Features ◽  
Oxidation Layers

Bobbin friction stir welding with a double-sided tool configuration produces a symmetrical solid-state joint. However, control of the process parameters to achieve defect-free welds is difficult. The internal flow features of the AA6082-T6 butt-joints in bobbin friction stir welding were evaluated using a set of developed reagents and optical microscopy. The key findings are that the dark curved patterns (conventionally called 'flow-arms'), are actually oxidation layers at the advancing side, and at the retreating side are elongated grains with a high-density of accumulation of sub-grain boundaries due to dynamic recrystallization. A model of discontinuous flow within the weld is proposed, based on the microscopic observations. It is inferred that the internal flow is characterized by packets of material ('flow patches') being transported around the pin. At the retreating side they experience high localized shearing at their mutual boundaries, as evidenced in high density of sub-grain boundaries. Flow patches at the advancing side are stacked on each other and exposed to oxidization.

scholarly journals 3D modeling of material flow and temperature in Friction Stir Welding

2009 ◽  
Vol 14 (3) ◽  
pp. 248-256 ◽  
Author(s):  
Diego Santiago ◽  
Santiago Urquiza ◽  
Guillermo Lombera ◽  
Luis de Vedia
Keyword(s):  
Friction Stir Welding ◽  
Material Flow ◽  
Frictional Heating ◽  
Welding Process ◽  
Experimental Tests ◽  
General Purpose ◽  
Friction Stir ◽  
Welding Equipment ◽  
Reducing Costs ◽  
Visualization Techniques

The process of Friction Stir Welding (FSW) is a welding method developed by the "The Welding Institute" (TWI) of England in 1991. The welding equipment consists of a tool that rotates and progresses along the joint of two restrained sheets. The joint is produced by frictional heating which causes the softening of both components into a viscous-plastic condition and also by the resultant flow between the sheets to be joined. Numerical Modeling of the process can provide realistic prediction of the main variables of the process, reducing the number of experimental tests, thus accelerating the design processes while reducing costs and optimizing the involved technological variables. In this study the friction stir welding process is modeled using a general purpose finite element based program, reproducing the material thermal map and the corresponding mass flow. Numerical thermal results are compared against experimental thermographic maps and numerical material flow results are compared with material flow visualization techniques, with acceptable concordance.

Numerical Study of the Tool Rake Angle Effect on the Material Flow in Friction Stir Welding Process

2007 ◽  
Author(s):  
Hosein Atharifar ◽  
Radovan Kovacevic
Keyword(s):  
Friction Stir Welding ◽  
Material Flow ◽  
Numerical Study ◽  
Welding Process ◽  
Rake Angle ◽  
Heat Transfer Analysis ◽  
Tool Geometry ◽  
Friction Stir ◽  
Tool Pin ◽  
Welding Processes

Minimizing consumed energy in friction stir welding (FSW) is one of the prominent considerations in the process development. Modifications of the FSW tool geometry might be categorized as the initial attempt to achieve a minimum FSW effort. Advanced tool pin and shoulder features as well as a low-conductive backing plate, high-conductive FSW tools equipped with cooling fins, and single or multi-step welding processes are all carried out to achieve a flawless weld with reduced welding effort. The outcomes of these attempts are considerable, primarily when the tool pin traditional designs are replaced with threaded, Trifiute or Trivex geometries. Nevertheless, the problem remains as to how an inclined tool affects the material flow characteristics and the loads applied to the tool. It is experimentally proven that a positive rake angle facilitates the traverse motion of the FSW tool; however, few computational evidences were provided. In this study, numerical material flow and heat transfer analysis are carried out for the presumed tool rake angle ranging from −4° to 4°. Afterwards, the effects of the tool rake angle to the dynamic pressure distribution, strain-rates, and velocity profiles are numerically computed. Furthermore, coefficients of drag, lift, and side force and moment applied to the tool from the visco-plastic material region are computed for each of the tool rake angles. Eventually, this paper confirms that the rake angle dramatically affects the magnitude of the loads applied to the FSW tool, and the developed advanced numerical model might be used to find optimum tool rake angle for other aluminum alloys.

Solid State Welding Process for Aerospace Components

2015 ◽  
Vol 1119 ◽  
pp. 597-600
Author(s):  
Hyun Ho Jung ◽  
Ye Rim Lee ◽  
Jong Hoon Yoon ◽  
Joon Tae Yoo ◽  
Kyung Ju Min ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Solid State ◽  
Structural Integrity ◽  
Welding Process ◽  
Diffusion Welding ◽  
Intimate Contact ◽  
Friction Stir ◽  
Base Materials ◽  
Welding Processes ◽  
And Diffusion

Since solid state welded joint is formed from an intimate contact between two metals at temperatures below the melting point of the base materials, the structural integrity of welding depends on time, temperature, and pressure. This paper provides some of examples of friction stir welding and diffusion welding process for aerospace components. Friction stir welding process of AA2195 was developed in order to study possible application for a large fuel tank. Massive diffusion welding of multiple titanium sheets was performed and successful results were obtained. Diffusion welding of dissimilar metals of copper and stainless steel was necessary to manufacture a scaled combustion chamber. Diffusion welding of copper and steel was performed and it is shown that the optimum condition of diffusion welding is 7MPa at 890°C, for one hour. It is shown that solid state welding processes can be successfully applied to fabricate lightweight aerospace parts.

Numerical Modeling of Thermal Field Distribution during Friction Stir Welding (FSW) of Dissimilar Materials

2016 ◽  
Vol 254 ◽  
pp. 261-266
Author(s):  
Bogdan Radu ◽  
Cosmin Codrean ◽  
Radu Cojocaru ◽  
Cristian Ciucă
Keyword(s):  
Numerical Modeling ◽  
Friction Stir Welding ◽  
Solid State ◽  
Thermal Field ◽  
Welding Process ◽  
Dissimilar Materials ◽  
Dissimilar Joints ◽  
Element Analysis ◽  
Friction Stir ◽  
The Cost

Friction Stir Welding (FSW) is an innovative solid state welding process, relatively new in industry, which allow welding of two or more materials which have very different properties, particularly thermal properties as fusion temperature, thermal expansion coefficient, specific heat and thermal conduction and have a predisposition to form intermetallic brittle phases, neither one of the components to be weld reach to the melting point. Being a solid state welding process temperature field is very important for the quality of the welded joint, and a lot of researches focused on this topic. This paper presents some results in modeling and estimation of thermal field developed during FSW of dissimilar joints, using Finite Element Analysis. Numerical modeling of thermal field allows engineers to predict, in advance, the evolution of temperature and to estimate the behavior of the welded materials during the welding process. This will reduce significantly the time and number of experiments that have to be carried out, in the process of establishing a good FSW technology, as well as reducing significantly the cost of the tests.

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