scholarly journals A fully coupled thermo-mechanical numerical modelling of the refill friction stir spot welding process in Alclad 7075-T6 aluminium alloy sheets

2020 ◽  
Vol 20 (4) ◽  
Author(s):  
Andrzej Kubit ◽  
Tomasz Trzepiecinski
Keyword(s):  
Numerical Modelling ◽  
Aluminium Alloy ◽  
Spot Welding ◽  
Numerical Models ◽  
Weld Zone ◽  
Welding Process ◽  
Friction Stir Spot Welding ◽  
Welding Parameters ◽  
Friction Stir ◽  
Fully Coupled

Abstract Refill friction stir spot welding (RFSSW) is a solid state joining technology that has the potential to replace processes such as the open-air fusion bonding technique and rivet technology in aerospace applications. Selection of proper RFSSW parameters is a crucial task which is important to ensure the mechanical strength of the joint. The aim of this paper is to undertake numerical modelling of the RFSSW process to understand the physics of the welding process, which involves large deformations, complex contact conditions and steep temperature gradients. Three-dimensional fully coupled thermo-mechanical models of RFSSW joints between Alclad 7075-T6 aluminium alloy sheets have been built in the finite-element-based program Simufact Forming. The simulation results included the temperature distribution and the stress and strain distributions in the overlap joint. The results of numerical computations have been compared with experimental ones. The numerical model was able to predict the mechanics of material flow during the joining of sheets of Alclad aluminium alloys using RFSSW. The predictions of the temperature gradient in the weld zone were in good agreement with the temperature measured experimentally. The numerical models that have been built are capable of simulating RFSSW to reduce the number of experiments required to set optimal welding parameters.

Influence of Heating Friction Stir Spot Welding Process Parameters on Steel Aluminum Forming Quality

2018 ◽  
Vol 917 ◽  
pp. 246-251
Author(s):  
Kai Xu ◽  
Shu Quan Zhang
Keyword(s):  
Spot Welding ◽  
Welding Process ◽  
Friction Stir Spot Welding ◽  
Joint Line ◽  
Welding Parameters ◽  
Forming Quality ◽  
Rotating Speed ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Welding Pressure

A lap welding experiment of DP590 steel and 6061 aluminum plate is carried out by using Heating Friction Stir Spot Welding (HFSSW) to study the influence of welding parameters on the forming quality. The results show that a lap joint with better forming can be obtained for the dissimilar metal of steel and aluminum. Under the condition that the rotating speed of the stirring tool is 1000r/min, the penetration depth, 0.2mm, the dwell time, 90s, the welding pressure, 0.2Mp, and the flow rate of cooling air, 20L/min, the forming quality of the surface of the joint line is good & bright, and the exit hole is also smaller. The mechanism of heat production is revealed in the following: the main heat is produced by the friction between the stirring tool shoulder and the welded part & between the probe and the welded part as well as by the latent heat resulted from the plastic deformation of the material in joint line during welding.

Simulation of a Refill Friction Stir Spot Welding Process Using a Fully Coupled Thermo-Mechanical FEM Model

2010 ◽  
Vol 132 (1) ◽  
Author(s):  
Karim H. Muci-Küchler ◽  
Sindhura Kalagara ◽  
William J. Arbegast
Keyword(s):  
Spot Welding ◽  
Welding Process ◽  
Element Model ◽  
Friction Stir Spot Welding ◽  
Temperature Deformation ◽  
Fem Model ◽  
Friction Stir ◽  
Simulation Results ◽  
Deformation Stress ◽  
Fully Coupled

Friction stir spot welding (FSSW) is a solid state joining technology that has the potential to be a replacement for processes like resistance spot welding and rivet technology in certain applications. To optimize the process parameters and to develop FSSW tools, it is important to understand the physics of this complex process that involves frictional contact, high temperature gradients, and large deformations. This paper presents a fully coupled thermo-mechanical finite element model (FEM) model of the plunge phase of a modified refill FSSW. The model was developed in Abaqus/Explicit and the simulation results included the temperature, deformation, stress, and strain distributions in the plates being joined. An experimental study was also conducted to validate the temperatures predicted by the model. The simulation results were in good agreement with the temperatures measured in the experiment. Also, the model was able to predict in a reasonable fashion the stresses and plastic strains in the plates.

scholarly journals Spot Welding of 6061 Aluminum Alloy by Friction Stir Spot Welding Process

2017 ◽  
Vol 7 (3) ◽  
pp. 1629-1632 ◽  
Author(s):  
M. A. Tashkandi ◽  
J. A. Al-jarrah ◽  
M. Ibrahim
Keyword(s):  
Welded Joints ◽  
Spot Welding ◽  
Shear Fracture ◽  
Welding Process ◽  
Friction Stir Spot Welding ◽  
Fracture Load ◽  
Welding Parameters ◽  
Friction Stir ◽  
Pull Out ◽  
Lap Shear

This study was focused on the effect of welding parameters on the lap-shear fracture load of the welded joints prepared by friction stir spot welding. Four different weld parameters were analyzed: rotational speed, dwell time, pin length and shoulder size of the welding tool. It was found that the lap-shear fracture load increases with an increase of the welding parameters to a limited value and decreases with further increase. The strong welded joints failed under nugget-pull out fracture.

scholarly journals A Weighting Grade-Based Optimization Method for Determining Refill Friction Stir Spot Welding Process Parameters

2019 ◽  
Vol 28 (10) ◽  
pp. 6471-6482
Author(s):  
Rafał Kluz ◽  
Andrzej Kubit ◽  
Tomasz Trzepiecinski ◽  
Koen Faes ◽  
Wojciech Bochnowski
Keyword(s):  
Process Parameters ◽  
Rotational Speed ◽  
Spot Welding ◽  
Load Capacity ◽  
Base Material ◽  
Welding Process ◽  
Friction Stir Spot Welding ◽  
Welding Parameters ◽  
Tool Rotational Speed ◽  
Friction Stir

Abstract The welding process used in fabricating thin-walled structures by refill friction stir spot welding (RFSSW) should be characterized by a high strength of welds and high process repeatability which is demonstrated by a small dispersion of the load capacity of the joints. The present work is designed to optimize RFSSW process parameters for 7075-T6 Alclad aluminum alloy sheets used to fabricate aircraft structures. The optimization was performed by scalarization of the objective function using the weighting grades method. The study considers the effect of process parameters, i.e., tool plunge depth, duration of welding, tool rotational speed, on the tensile/shear strength of the joints, and dispersion of the load capacity. It was found that it was possible to choose the optimal welding parameters taking into account maximization of the load capacity and minimization of the dispersion of the joint strength via a best compromise between the tool rotational speed ensuring adequate plasticization of the base material and the duration of welding ensuring that a fine-grained joint microstructure is obtained.

Experimental Investigation on Refill Friction Stir Spot Welding Process of Aluminum Alloys

2013 ◽  
Vol 345 ◽  
pp. 243-246 ◽  
Author(s):  
Hong Gang Yang ◽  
Hai Jun Yang
Keyword(s):  
Aluminum Alloys ◽  
Spot Welding ◽  
Welding Process ◽  
Friction Stir Spot Welding ◽  
Welding Parameters ◽  
Welding Time ◽  
Welding Quality ◽  
Tensile Shear ◽  
Rotating Speed ◽  
Friction Stir

With the growing demand for lightweight reduction and environment protection, lightweight materials like aluminum and magnesium alloys have been widely applied in the automotive and aerospace industry. Being a solid state welding process, refill friction stir spot welding (RFSSW) is suitable for spot joining lightweight metals. In the present paper, the mechanical properties and microstructure of the RFSSW joints of 6061-T6 aluminum alloys were investigated. The influence of welding parameters, such as plunge depth, rotating speed and welding time, on tensile-shear strength was conducted through experiments. It is found that the tensile-shear strength is increased with the increase of plunge depth, rotating speed and welding time. And welding time is found to be an important key factor which affects welding quality. Research results can provide guidance for welding parameters optimization and welding quality promotion of RFSSW process of aluminum alloys.

Effects of bottom plate in friction stir welding of AA6061-T6

2020 ◽  
Vol 118 (1) ◽  
pp. 108
Author(s):  
M.A. Vinayagamoorthi ◽  
M. Prince ◽  
S. Balasubramanian
Keyword(s):  
Mechanical Properties ◽  
Axial Load ◽  
Weld Zone ◽  
Welding Process ◽  
Bottom Plate ◽  
Welding Parameters ◽  
Nugget Zone ◽  
Friction Stir ◽  
Weld Joints ◽  
Fine Grain

The effects of 40 mm width bottom plates on the microstructural modifications and the mechanical properties of a 6 mm thick FSW AA6061-T6 joint have been investigated. The bottom plates are placed partially at the weld zone to absorb and dissipate heat during the welding process. An axial load of 5 to 7 kN, a rotational speed of 500 rpm, and a welding speed of 50 mm/min are employed as welding parameters. The size of the nugget zone (NZ) and heat-affected zone (HAZ) in the weld joints obtained from AISI 1040 steel bottom plate is more significant than that of weld joints obtained using copper bottom plate due to lower thermal conductivity of steel. Also, the weld joints obtained using copper bottom plate have fine grain microstructure due to the dynamic recrystallization. The friction stir welded joints obtained with copper bottom plate have exhibited higher ductility of 8.9% and higher tensile strength of 172 MPa as compared to the joints obtained using a steel bottom plate.

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