Simulation of heat transfer and analysis of impact of tool pin geometry and tool speed during friction stir welding of AZ80A Mg alloy plates

2020 ◽  
Vol 34 (10) ◽  
pp. 4239-4250
Author(s):  
S. D. Dhanesh Babu ◽  
P. Sevvel ◽  
R. Senthil Kumar
2021 ◽  
Vol 49 (1) ◽  
pp. 78-86
Author(s):  
Stephen Leon ◽  
G. Bharathiraja ◽  
V. Jayakumar

In friction stir welding, lesser tool life restricts the usage of non-circular pin in friction stir welding tool eventhough it delivers comparatively better weld joints than circular pin. Process peak temperature during the process affects the shear strength of the flowing material around the tool pin. Maintaining the process peak temperature as low as possible improves the properties in heat affected zone but on the other hand it increases the stress on the tool pin.Especially on the usage of non-circular pin, the pin surface experiences uneven stress distribution and causes premature tool failure. In this paper, optimum thermal environment through proper selection of process parameters and dwell period with respect to the pin geometry are analysed. A comparative analysis is also made to understand the impact of increase in flat surfaces in the pin surface on weld quality in the view of developing a suitable thermal environment that can improve tool life without compromising joint strength. Apart from this, optimum dwell period for the chosen tool pin geometry is analysed based on the empirical softening temperature of the material.


Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7565
Author(s):  
Supat Chupradit ◽  
Dmitry Olegovich Bokov ◽  
Wanich Suksatan ◽  
Michał Landowski ◽  
Dariusz Fydrych ◽  
...  

The friction stir welding (FSW) of tool pin geometry plays a critical role in the final properties of the produced joint. The tool pin geometry directly affects the generation of heat and the flow of internal materials during the FSW process. The effects of the FSW tool pin angle on heat generation and internal flow have not been quantitatively investigated in detail. In this manuscript, a validated Computational Fluid Dynamic (CFD) model was implemented to analyze the effects of pin angle on the thermo-mechanical action during the FSW process of AA5058 Al-Mg alloy. Experimental test results validate the thermal outcomes of the used model. The obtained results revealed that, when the pin angle is increased, the heat generation decreases while the mechanical action of the tool increases. The internal heat distribution at a higher pin angle is symmetrical. The higher mechanical action of the tool decreases the viscosity of the internal materials and increases stirring action (materials flow) around the pin. Furthermore, plastic flow near the tool increased stirring action and formed a larger stir zone in the joint area.


2019 ◽  
Vol 43 (1) ◽  
pp. 132-141 ◽  
Author(s):  
P. Sevvel ◽  
C. Satheesh ◽  
V. Jaiganesh

Dissimilar friction stir welding of the AZ80A Mg alloy as the advancing side and the AZ91C Mg alloy as the retreating side was carried out at a constant feed rate of 75 mm/min using a taper cylindrical pin profiled tool at different tool rotational speeds. Defect free welds were produced in the 700–900 rpm rotational speed range. During friction stir welding, extrusion of metal took place in the advancing side and this extruded material was dynamically recrystallized and redeposited on the retreating side. This experimental investigation revealed that friction stir welding leads to the formation of comparatively finer sized grains on the retreating side of the thermo-mechanically affected zone compared to grains in the thermo-mechanically affected zone on the advancing side. Moreover, the heat affected zone of AZ80A possessed fine sized grains compared to the heat affected zone of AZ91C. Additionally, increasing tool rotational speed influenced the tensile strength of the fabricated joints.


2016 ◽  
Vol 25 (5-6) ◽  
pp. 179-182
Author(s):  
C.B. Jagadeesha

AbstractSince its inception no one has done analysis and design of FSW tool. Initial dimensions of FSW tool are decided by educated guess. Optimum stresses on tool pin have been determined at optimized parameters for bead on plate welding on AZ31B–O Mg alloy plate. Fatigue analysis showed that the chosen FSW tool for the welding experiment has not ∞ life and it has determined that the life of FSW tool is 2.66×105 cycles or revolutions. So one can conclude that any arbitrarily decided FSW tool generally has finite life and cannot be used for ∞ life. In general, one can determine the suitability of tool and its material to be used in FSW of the given workpiece materials in advance by this analysis in terms of fatigue life of the tool.


Author(s):  
M Song ◽  
R Kovacevic

A mathematical model to describe the detailed three-dimensional transient heat transfer process in friction stir welding (FSW) is presented. This work is both theoretical and experimental. An explicit central differential scheme is used in solving the control equations, the heat transfer phenomena during the tool penetrating, the welding and the tool-removing periods that are studied dynamically. The heat input from the tool shoulder is modelled as a frictional heat and the heat from the tool pin is modelled as a uniform volumetric heat generated by the plastic deformation near the pin. The temperature variation during the welding is also measured to validate the calculated results. The calculated results are in good agreement with the experimental data.


2021 ◽  
Vol 22 (2) ◽  
pp. 352-363
Author(s):  
Stephen Leon Joseph Leon ◽  
Alfred Franklin Varghese ◽  
Joseph Michel ◽  
Gopinath Gunasekaran

Frictional heat generation in the tool/matrix interface followed by the stirring of material along the weld line causes plasticized solid state joining in friction stir welding. In this paper, the existing torque based thermo-mechanical model for the tools with cylindrical pins is remodified for the polygonal tool pin profile by introducing novel multiplication factors with respect to the number of sides in the tool pin geometry. The variation in the effective heat supply with respect to the chosen pin geometry was analyzed. A comparative analysis of the proposed analytical model with the existing model was also carried out to understand the accuracy of the proposed model.  Furthermore, a transient thermal numerical modelling was carried out in the view of understanding the change in process peak temperature in the stir zone and change in temperature gradient along the heat affected zone with respect to the change in pin geometry for the opted set of process input parameters. An analytically estimated heat-input-based numerical model was adopted in the present study. It was observed that the process peak temperature was directly proportional to the number of sides in the tool pin. ABSTRAK: Penjanaan haba geseran antara muka pada alat/matrik diikuti dengan pengacauan material sepanjang garis kimpalan menyebabkan keadaan plastik pepejal melekat bersama geseran kimpalan pengacau. Kajian ini berkaitan tork sedia ada berdasarkan model mekanikal-terma bagi alat pin silinder yang terubah suai bagi profil pin alat poligon dengan memperkenalkan faktor gandaan berdasarkan bilangan sisi geometri alat pin. Perubahan pada bekalan haba efektif berdasarkan geometri pin pilihan telah dikaji. Analisis bandingan pada model analitik yang dicadang bersama model sedia ada, telah dilakukan bagi memahami ketepatan model cadangan. Tambahan, model transien numerikal terma telah dibuat bagi memahami proses perubahan suhu puncak ketika zon pengacauan dan perubahan gradien suhu sepanjang zon terkena haba perubahan geometri pin pada set proses parameter input terpilih. Kajian ini mengaplikasi model numerik berdasarkan input anggaran haba secara analitik. Dapatan kajian menunjukkan suhu puncak proses adalah berkadar langsung dengan bilangan sisi pin alat.


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