A Thermo-Fluid Analysis of the Friction Stir Welding Process

2007 ◽  
Vol 539-543 ◽  
pp. 3832-3837 ◽  
Author(s):  
D. Jacquin ◽  
Christophe Desrayaud ◽  
Frank Montheillet
Keyword(s):  
Friction Stir Welding ◽  
Bulk Material ◽  
Welding Process ◽  
Vertical Motion ◽  
Velocity Fields ◽  
Fluid Simulation ◽  
Metal Sheet ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Fluid Analysis

The thermo-mechanical simulation of Friction Stir Welding focuses the interest of the welding scientific and technical community. However, literature reporting material flow modeling is rather poor. The present work is based on the model developed by Heurtier [2004] and aims at improving this thermo-fluid simulation developed by means of fluid mechanics numerical and analytical velocity fields combined together. These various velocity fields are investigated separately and especially according to the power dissipated during the flow. Boundary conditions are considered through a new approach based on the kinematic analysis of the thread of the pin. An equilibrium is established between the vertical motion of the bulk material dragged in the depth of the metal sheet, and its partial circulation around the pin. The analyses of the obtained velocity fields enable the understanding of the welded zone asymmetry and highlights the bulk material mixing between the welded coupons in the depth of the sheet. A regression is performed on the relative sliding velocity of the aluminium according to the surface of the tool: shoulder and pin. Two dimension flow lines in the depth of the metal sheet are then obtained and successfully compared with the results obtained by Colegrove (2004) [1].

On the problem of tool destruction when obtaining fixed joints of thick-walled aluminum alloy blanks by friction welding with mixing

2021 ◽  
Vol 23 (3) ◽  
pp. 72-83
Author(s):  
Kirill Kalashnikov ◽  
◽  
Andrey Chumaevskii ◽  
Tatiana Kalashnikova ◽  
Aleksey Ivanov ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Friction Welding ◽  
Welding Process ◽  
High Strength ◽  
Heterogeneous Structure ◽  
Adhesive Interaction ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Electric Erosion

Introduction. Among the technologies for manufacturing rocket and aircraft bodies, marine vessels, and vehicles, currently, more and more attention is paid to the technology of friction stir welding (FSW). First of all, the use of this technology is necessary where it is required to produce fixed joints of high-strength aluminum alloys. In this case, special attention should be paid to welding thick-walled blanks, as fixed joints with a thickness of 30.0 mm or more are the target products in the rocket-space and aviation industries. At the same time, it is most prone to the formation of defects due to uneven heat distribution throughout the height of the blank. It can lead to a violation of the adhesive interaction between the weld metal and the tool and can even lead to a destruction of the welding tool. The purpose of this work is to reveal regularities of welding tool destruction depending on parameters of friction stir welding process of aluminum alloy AA5056 fixed joints with a thickness of 35.0 mm. Following research methods were used in the work: the obtaining of fixed joints was carried out by friction welding with mixing, the production of samples for research was carried out by electric erosion cutting, the study of samples was carried out using optical metallography methods. Results and discussion. As a result of performed studies, it is revealed that samples of aluminum alloy with a thickness of 35.0 mm have a heterogeneous structure through the height of weld. There are the tool shoulder effect zone and the pin effect zone, in which certain whirling of weld material caused by the presence of grooves on tool surface is distinctly distinguished. It is shown that the zone of shoulders effect is the most exposed to the formation of tunnel-type defects because of low loading force and high welding speeds. It is revealed that tool destruction occurs tangentially to the surface of the tool grooves due to the high tool load and high welding speeds.

Optimization of Welding Process Parameters in Novel Friction Stir Welding of Polyamide 66 Joints

2019 ◽  
Vol 969 ◽  
pp. 828-833 ◽  
Author(s):  
R. Nandhini ◽  
R. Dinesh Kumar ◽  
S. Muthukumaran ◽  
S. Kumaran
Keyword(s):  
Tensile Strength ◽  
Friction Stir Welding ◽  
Process Parameters ◽  
Welding Process ◽  
Polyamide 66 ◽  
Friction Stir ◽  
Response Characteristics ◽  
Tool Shoulder ◽  
Stereo Microscope ◽  
Friction Plate

The friction stir welding of polyamide 66 with a specially modified tool is studied. A variation of the conventional friction stir welding is investigated by incorporating a friction plate for the purpose of heating the polymer in the course of welding process through the tool shoulder. This in turn, improves the efficiency of the weld. The association of the welding process parameters and the weld performance has been investigated by the grey relational analysis with multi response characteristics like weld tensile strength, percent elongation and hardness. Macrostructure of the weld joint cross section has been explored by Stereo microscope. The maximum weld tensile strength of 63 MPa and a Shore hardness of 60 D at the weld nugget are obtained. The hardness profiles of the welded samples have been analyzed in this investigation.

A Study on the Thermal Deformation of Fillet Joint Friction Stir Welding

2020 ◽  
Author(s):  
Sungwook Kang ◽  
Jaewoong Kim ◽  
Donghyun Kim ◽  
Kwangjin Lee ◽  
Yoonchul Jung
Keyword(s):  
Friction Stir Welding ◽  
Heat Source ◽  
Welding Process ◽  
Frictional Heat ◽  
Process Conditions ◽  
Joint Friction ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Tool Shape ◽  
Fillet Joint

Abstract In this study, experiments and simulations were performed for fillet joint friction stir welding according to tool shape and welding conditions. Conventional butt friction stir welding has good weldability because heat is generated by friction with the bottom of the tool shoulder. However, in the case of fillet friction stir welding, the frictional heat is not sufficiently generated at the bottom of the tool shoulder due to the shape of the tool and the shape of the joint. Therefore, it is important to sufficiently generate frictional heat by slowing the welding speed as compared to butt welding. In this study, experiments and simulations were carried out on an aluminum battery housing made by friction stir welding an extruded material with a fillet joint. The temperature of the structure was measured using thermocouple during welding, and the heat source was calculated through correlation analysis. Thermal elasto-plastic analysis of the structure was carried out using the calculated heat source and geometric boundary conditions. It is confirmed that the experimental results and the simulation results are well matched. Based on the results of the study, the deformation of the structure can be calculated through simulation even if the tool shape and welding process conditions change.

scholarly journals Effect of Shoulder–Workpiece Interference Depth on the Quality of Friction Stir Welding of AA7075-T6 Aluminium Alloy

2019 ◽  
Vol 26 (1) ◽  
pp. 150-159
Author(s):  
Abbas Akram Abbas ◽  
Hazim H. Abdulkadhum
Keyword(s):  
Friction Stir Welding ◽  
Aluminium Alloy ◽  
Welding Process ◽  
High Strength ◽  
Filling Defect ◽  
Welding Quality ◽  
Left Hand ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Welding Surface

The joining of high strength aluminium alloy AA7075-T6 sheets of 3 mm thickness was an attempt utilizing friction stir welding process. The effect of interference depth between tool shoulder and surface workpiece on the welding quality and its effect on the mechanical and metallography properties of welded joints were studied. This process is carried out using a composite tool consists of a concave shoulder made of H13 tool steel and cylindrical left-hand thread with 1mm pitch pin (probe) made of cobalt-based alloy MP159. The dimensions of tools were 14mm shoulder diameter and the pin has 5mm diameter and 2.7mm length. The tool rotation speed and welding speed were 981 rpm 169 mm/min respectively, and the tilt angle was 2°. The range of interference depth between the shoulder and workpiece was selected (0.05, 0.1, 0.15, 0.2, 0.25, and 0.3) mm. various tests were executed to evaluate the welding quality. The results show that lack of filling defect appeared on the welding surface at the interference depth 0.05 mm. An invisible tunnel and lack of penetration in the bottom of the stir zone appeared when the interference depths were 0.1 mm and 0.15 mm. Defect-free welds obtained when interference depths were (0.2, 0.25, and 0.3) mm. The welding efficiency of the defect-free welds was in the range (85.3-92.3%) depending on the ultimate tensile strength of the parent alloy.

scholarly journals Analysis of Tools used in Friction Stir Welding process

2018 ◽  
Vol 8 (6) ◽  
Author(s):  
Akshansh Mishra ◽  
Adarsh Tiwari ◽  
Mayank Kumar Shukla ◽  
A. Razal Rose
Keyword(s):  
Friction Stir Welding ◽  
Critical Role ◽  
Base Material ◽  
Welding Process ◽  
Tool Geometry ◽  
Work Piece ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Tool Pin ◽  
Joining Process

A relatively new joining process, friction stir welding (FSW) produces no fumes; uses no filler material; and can join aluminium alloys, copper, magnesium, zinc, steels, and titanium. FSW sometimes produces a weld that is stronger than the base material. The tool geometry plays a critical role in material flow and governs the transverse rate at which FSW can be conducted. The tool serves three primary functions, i.e., (a) heating of the work piece, (b) movement of material to produce the joint, and (c) containment of the hot metal beneath the tool shoulder. Heating is created within the work piece by friction between both the rotating tool pin and shoulder and by severe plastic deformation of the work.

scholarly journals Experimental and numerical thermo-mechanical analysis of friction stir welding of high-strength alluminium alloy

2014 ◽  
Vol 18 (suppl.1) ◽  
pp. 29-38 ◽  
Author(s):  
Darko Veljic ◽  
Aleksandar Sedmak ◽  
Marko Rakin ◽  
Nikola Bajic ◽  
Bojan Medjo ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Welding Process ◽  
Vertical Direction ◽  
High Strength ◽  
Temperature Fields ◽  
Bottom Surface ◽  
Arbitrary Lagrangian Eulerian ◽  
Welding Zone ◽  
Friction Stir ◽  
Tool Shoulder

This paper presents experimental and numerical analysis of the change of temperature and force in the vertical direction during the friction stir welding of high-strength aluminium alloy 2024 T3. This procedure confirmed the correctness of the numerical model, which is subsequently used for analysis of the temperature field in the welding zone, where it is different to determine the temperature experimentally. 3D finite element model is developed using the software package Abaqus; arbitrary Lagrangian-Eulerian formulation is applied. Johnson-Cook material law and Coulomb?s Law of friction are used for modelling the material behaviour. Temperature fields are symmetrical with respect to the welding line. The temperature values below the tool shoulder, i.e. in the welding zone, which are reached during the plunge stage, are approximately constant during the entire welding process and lie within the interval 430-502?C. The temperature of the material in the vicinity of the tool is about 500?C, while the values on the top surface of the welding plates (outside the welding zone, but close to the tool shoulder) are about 400?C. The temperature difference between the top and bottom surface of the plates is small, 10-15?C.

scholarly journals Temperature Monitoring and Material Flow Characteristics of Friction Stir Welded 2A14-t6 Aerospace Aluminum Alloy

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3387 ◽  
Author(s):  
Tingke Wu ◽  
Fengqun Zhao ◽  
Haitao Luo ◽  
Haonan Wang ◽  
Yuxin Li
Keyword(s):  
Friction Stir Welding ◽  
Material Flow ◽  
Flow Model ◽  
Welding Process ◽  
Temperature Monitoring ◽  
Measuring System ◽  
Welding Parameters ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Tool Pin

Aiming at the problems that the temperature in the welding area of friction stir welding (FSW) is difficult to measure and the joints are prone to defects. Hence, it is particularly important to study the material flow in the welding area and improve the welding quality. The temperature of the tool shoulder and the tool pin was monitored by the wireless temperature measuring system. The finite element model of friction stir welding was established and the welding conditions were numerically simulated. The flow law of material of the friction stir welding process was studied by numerical simulation. The material flow model was established by combining the microstructure analysis results, and the forming mechanism of the defects was analyzed. The results show that the temperature in the welding zone is the highest at 1300 rpm, and the temperature at the tool shoulder is significantly higher than that at the tool pin in the welding stage. When high-rotation speeds (HRS) are chosen, the material beneath the tool shoulder tends to be extruded into the pin stirred zone (PSZ) after flowing back to the advancing side. This will cause turbulence phenomenon in the advancing side of the joint, which will easily lead to the formation of welding defects. In the future, temperature monitoring methods and the flow model of material can be used to optimize the welding parameters.

scholarly journals Influence of material velocity on heat generation during linear welding stage of friction stir welding

2016 ◽  
Vol 20 (5) ◽  
pp. 1693-1701
Author(s):  
Alin Murariu ◽  
Darko Veljic ◽  
Dragana Barjaktarevic ◽  
Marko Rakin ◽  
Nenad Radovic ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Friction Stir Welding ◽  
Heat Generation ◽  
Welding Process ◽  
Slip Rate ◽  
Frictional Heat ◽  
Al Alloy ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Tool Pin

The heat generated during friction stir welding (FSW) process depends on plastic deformation of the material and friction between the tool and the material. In this work, heat generation is analysed with respect to the material velocity around the tool in Al alloy Al2024-T351 plate. The slip rate of the tool relative to the workpiece material is related to the frictional heat generated. The material velocity, on the other hand, is related to the heat generated by plastic deformation. During the welding process, the slippage is the most pronounced on the front part of the tool shoulder. Also, it is higher on the retreating side than on the advancing side. Slip rate in the zone around the tool pin has very low values, almost negligible. In this zone, the heat generation from friction is very low, because the material is in paste-like state and subjected to intensive plastic deformation. The material flow velocity around the pin is higher in the zone around the root of the pin. In the radial direction, this quantity increases from the pin to the periphery of the tool shoulder.

scholarly journals A Comparative Study of Tool-Pin Profile on Process Response of Friction Stir Welding of AA6082-T6 Aluminium Alloy

2017 ◽  
Vol 61 (4) ◽  
pp. 296 ◽  
Author(s):  
Kayode Oyedemi ◽  
Patrick McGrath ◽  
Hannalie Lombard ◽  
Balázs Varbai
Keyword(s):  
Friction Stir Welding ◽  
Material Flow ◽  
Dwell Time ◽  
Research Work ◽  
Welding Process ◽  
Nugget Zone ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Tool Pin ◽  
Welding Direction

This paper presents research work conducted to experimentally establish the process response of two diverse shaped tool-pin profiles for friction stir welding (FSW) AA6082-T6 aluminium. The dwell time was optimised by plunging each tool-pin into a plate sample until the spindle torque stabilised thus ensuring sufficient plasticised material in contact with tool shoulder and the tool-pins. The welds were conducted by employing the optimised dwell time, which in turn revealed a minimised process response time and distance to reach weld stability with respect to (1) the force exerted on the tool-pin in the welding direction, Fx , and (2) the spindle torque, T, during the welding process. Both Fx and T stabilised well within the set (pre-determined) ramp-up distance of 20 mm, indicating that the effective (useful) weld length is maximised. The macrographs also revealed good dynamic material flow within the nugget zone regions and more evident in the nugget zone of the flared tool.

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