scholarly journals Friction Stir Welding and Friction Spot Stir Welding Processes of Polymers—State of the Art

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2291 ◽  
Author(s):  
Francesco Lambiase ◽  
Hamed Aghajani Derazkola ◽  
Abdolreza Simchi

In the last decade, the friction stir welding of polymers has been increasingly investigated by the means of more and more sophisticated approaches. Since the early studies, which were aimed at proving the feasibility of the process for polymers and identifying suitable processing windows, great improvements have been achieved. This owes to the increasing care of academic researchers and industrial demands. These improvements have their roots in the promising results from pioneer studies; however, they are also the fruits of the adoption of more comprehensive approaches and the multidisciplinary analyses of results. The introduction of instrumented machines has enabled the online measurement of processing loads and temperature, and critical understanding of the principal aspects affecting the material flow and welds quality. Such improvements are also clearly demonstrated by the increase of the strength of recent joints (up to 99% of joining efficiency) as compared to those reached in early researches (almost 47%). This article provides a comprehensive review of the recent progresses on the process fundamentals, quality assessment and the influence of process parameters on the mechanical behavior. In addition, emphasis is given to new developments and future perspectives.

Author(s):  
Hosein Atharifar ◽  
Radovan Kovacevic

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.


2019 ◽  
Vol 297 ◽  
pp. 1-16
Author(s):  
Zineelabidine Harchouche ◽  
Mokhtar Zemri ◽  
Abdelkader Lousdad

Friction stir welding is a solid-phase welding process based on the mixing of the pasty material in the stirred zone. The main advantage of this technique is the ability to weld metal alloys which are generally difficult to weld by conventional welding processes. In this paper an analytical model is proposed for the description in 2D the distribution of the material (fluid) flow in the vicinity of the tool pin during friction stir welding process "FSW". For this reason, the analytical solutions are built on the basis of traditional problem of mechanics of the fluids which is used to solve the equation associated with this problem. Furthermore, the aim is to make an analytical study of these aspects for a better understanding of this phenomenon. This method provides a reduction in computational time compared to those required for finite or differential elements methods. Moreover, it highlights on the effects of the different parameters on the material flow during welding.


2018 ◽  
Vol 68 (5) ◽  
pp. 512-518 ◽  
Author(s):  
Suresh Meshram ◽  
Madhusudhan Reddy

Heat treatable aluminium alloy AA2219 is widely used for aerospace applications, welded through gas tungsten and gas metal arc welding processes. Welds of AA2219 fabricated using a fusion welding process suffers from poor joint properties or welding defects due to melting and re-solidification. Friction stir welding (FSW) is a solid-state welding process and hence free from any solidification related defects. However, FSW also results in defects which are not related to solidification but due to improper process parameter selection. One of the important process parameters, i.e., tool tilt angle plays a critical role in material flow during FSW, controlling the size and location of the defects. Effect of tool tilt angle on material flow and defects in FSW is ambiguous. A study is therefore taken to understand the role of tool tilt angle on FSW defects. Variation in temperature, forces, and torque generated during FSW as a result of different tool tilt angles was found to be responsible for material flow in the weld, controlling the weld defects. An intermediate tool tilt angle (1o-2o) gives weld without microscopic defect in 7 mm thick AA2219 for a given set of other process parameters. At this tool tilt angle, x-force, and Z- force is balanced with viscosity and the material flow strain rate sufficient for the material to flow and fill internal voids or surface defects in the weld.


2013 ◽  
Vol 652-654 ◽  
pp. 2315-2319
Author(s):  
Zheng Hua Guo ◽  
Wen Long Liu ◽  
Cheng Zhong Li ◽  
Jun Hua Cui ◽  
Gang Yao Zhao

Friction stir welding, which is considered to be a solid-state welding, possesses several advantages over conventional welding processes, is an effective approach to weld high-strength, large thickness and dissimilar materials. Material flow behavior on FSW was generally acknowledged to have effects on weld property. The material flow behavior in thickness direction of advancing and retreating side was analyzed by a numerical model established with cone-shape tool pin. Numerical results indicate that there exist material flow in thickness direction on both sides and the behavior was affected by welding and tool pin rotation speed. Decrease welding speed or increase rotation speed would make material deformation intensified, and increase the fluidity of the material.


2013 ◽  
Vol 774-776 ◽  
pp. 1155-1159 ◽  
Author(s):  
Xiao Cong He

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.


2010 ◽  
Vol 160 ◽  
pp. 313-318 ◽  
Author(s):  
Uceu Suhuddin ◽  
Sergey Mironov ◽  
H. Takahashi ◽  
Yutaka S. Sato ◽  
Hiroyuki Kokawa ◽  
...  

The “stop-action” technique was employed to study grain structure evolution during friction-stir welding of AZ31 magnesium alloy. The grain structure formation was found to be mainly governed by the combination of the continuous and discontinuous recrystallization but also involved geometric effect of strain and local grain boundary migration. Orientation measurements showed that the deformation mode was very close to the simple shear associated with the rotating pin and material flow arose mainly from basal slip.


2011 ◽  
Vol 189-193 ◽  
pp. 3266-3269 ◽  
Author(s):  
Yu Hua Chen ◽  
Peng Wei ◽  
Quan Ni ◽  
Li Ming Ke

Titanium alloy TC1 and Aluminum alloy LF6 were jointed by friction stir welding (FSW), and the influence of process parameters on formation of weld surface, cross-section morphology and tensile strength were studied. The results show that, Titanium and Aluminum dissimilar alloy is difficult to be joined by FSW, and some defects such as cracks and grooves are easy to occur. When the rotational speed of stir head(n) is 750r/min and 950r/min, the welding speed(v) is 118mm/min or 150mm/min, a good formation of weld surface can be obtained, but the bonding of titanium/aluminum interface in the cross-section of weld joint is bad when n is 750r/min which results in a low strength joint. When n is 950r/min and v is 118mm/min,the strength of the FSW joint of Titanium/Aluminum dissimilar materials is 131MPa which is the highest.


2013 ◽  
Vol 856 ◽  
pp. 16-21
Author(s):  
R. Beygi ◽  
Mohsen Kazeminezhad ◽  
A.H. Kokabi ◽  
S. Mohammad Javad Alvani ◽  
D. Verdera ◽  
...  

In this study friction stir welding of Al-Cu laminated composites were carried out by two different tool geometries. Welding procedure was carried out from both sides of Al and Cu. Analyzing cross section of welds showed that different contact conditions between shoulder and material, offers different material flow behavior which is dependent on the tool geometry. SEM analyses showed that mixing of materials in nugget region is more pronounced in the advancing side. Also XRD results indicated that welding from Cu side, leads to intermetallic formation in mixed regions.


Author(s):  
Debtanay Das ◽  
Swarup Bag ◽  
Sukhomay Pal ◽  
M. Ruhul Amin

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.


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