Friction stir welding of lap joints: Influence of process parameters on the metallurgical and mechanical properties

2009 ◽  
Vol 519 (1-2) ◽  
pp. 19-26 ◽  
Author(s):  
G. Buffa ◽  
G. Campanile ◽  
L. Fratini ◽  
A. Prisco
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Process Parameters ◽  
Lap Joints ◽  
Influence Of Process Parameters ◽  
Friction Stir

A Numerical and Experimental Analysis of Microstructural Aspects in AA2024-T3 Friction Stir Welding

2013 ◽  
Vol 554-557 ◽  
pp. 1022-1030 ◽  
Author(s):  
Pierpaolo Carlone ◽  
Gaetano S. Palazzo
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Heat Generation ◽  
Process Parameters ◽  
Fluid Dynamic ◽  
Weld Line ◽  
Work Piece ◽  
Viscoplastic Material ◽  
Influence Of Process Parameters ◽  
Friction Stir

In recent years, remarkable interest has been focused on the Friction Stir Welding (FSW) process, by academic as well as industrial research groups. Conceptually, the FSW process is quite simple: a non-consumable rotating tool is plunged between the adjoining edges of the parts to be welded and moved along the desired weld line. Frictional and viscous heat generation increases the work piece temperature, softening the processing material and forcing it to flow around the pin. Although FSW has been effectively applied in welding of several materials, such as copper, steel, magnesium, and titanium, considerable attention is still focused on aluminum welding, in particular for transport applications. Recent literature clearly evidenced microstructural variations in the stir zone, imputable to continuous dynamic recrystallization phenomena, leading to the formation of a finer equiaxed grains. Moreover, depending on the specific alloy, thermal cycles can induce coarsening or dissolution of precipitates in the thermo-mechanically affected zone (TMAZ) and in the heat affected zone (HAZ). The influence of the aforementioned microstructural aspects on mechanical properties and formability of FSWed assemblies is also well recognized. The aim of this paper is to numerically and experimentally investigate the influence of process parameters, namely rotating speed and welding speed, on microstructural aspects in AA2024-T3 friction stir butt welds. A three-dimensional Computational Fluid Dynamic (CFD) model has been implemented to simulate the process. A viscoplastic material model, based on Wright and Sheppard modification of the constitutive model initially proposed by Sellars and Tegart has been implemented in the commercial package ANSYS CFX, considering an Eulerian framework. Tool-workpiece interaction has been modeled assuming partial sticking/sliding condition, and incorporating both frictional and viscous contributions to the heat generation. Microstructural aspects have been numerically predicted using the Zenner-Holloman parameter and experimentally measured by means of conventional metallographic techniques. Satisfactory agreement has been found between simulated and experimental results. The influence of process parameters on mechanical properties has also been highlighted.

A study on the effect of cooling on microstructure and mechanical properties of friction stir-welded AA5086 aluminum butt and lap joints

2017 ◽  
Vol 233 (6) ◽  
pp. 1156-1165 ◽  
Author(s):  
Adel Sedaghati ◽  
Hamed Bouzary
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Feed Rate ◽  
Rotational Speed ◽  
Lap Joints ◽  
Tensile Behavior ◽  
Water Cooling ◽  
Friction Stir ◽  
Microstructural Behavior ◽  
Constant Feed Rate

In this paper, the effect of water cooling on mechanical properties and microstructure of AA5086 aluminum joints during friction stir welding is investigated. For doing so, the mechanical and microstructural behavior of samples welded both in air and in water was analyzed. Tests were performed involving both butt and lap welds and the results were compared. The effect of rotational speed at constant feed rate of 50 mm/min and changing rotational speed ranging from 250 to 1250 r/min was investigated. The results showed a significant change in the tensile behavior of the butt-welded specimens due to water cooling. In addition, welding was performed at constant spindle speed of 800 r/min and various traverse speeds (25 mm/min to 80 mm/min) to determine the effect of feed rate. The strength increases at first, but then decreases dramatically along with the feed rate which is due to the occurrence of a groove defect. Results showed some generally positive impacts of water cooling which are discussed in terms of tensile results, hardness distributions and microstructure analysis.

scholarly journals Longitudinal Residual Stress Analysis in AA2024-T3 Friction Stir Welding

2013 ◽  
Vol 7 (1) ◽  
pp. 18-26 ◽  
Author(s):  
Pierpaolo Carlone ◽  
Gaetano S. Palazzo
Keyword(s):  
Friction Stir Welding ◽  
Residual Stresses ◽  
Process Parameters ◽  
Material Properties ◽  
Stress Measurement ◽  
Dynamic Performance ◽  
Contour Method ◽  
Influence Of Process Parameters ◽  
Friction Stir ◽  
Longitudinal Residual Stress

Friction Stir Welding (FSW) is an innovative solid-state joining process, which is gaining a great deal of attention in several applicative sectors. The opportune definition of process parameters, i.e. minimizing residual stresses, is crucial to improve joint reliability in terms of static and dynamic performance. Longitudinal residual stresses, induced by FSW in AA2024-T3 butt joints, have been inferred by means of a recently developed technique, namely the contour method. Two approaches to stress measurement have been adopted; the former is based on the assumption of uniform material properties, the latter takes into account microstructural effects and material properties variations in the welding zones. The influence of process parameters, namely rotating and welding speeds, on stress distribution is also discussed.

Thermo-Mechanical Characterization of Friction Stir Spot Welded Sheets: Experimental and FEM Comparison between AA6060 and AA7050 Alloys

2015 ◽  
Vol 651-653 ◽  
pp. 1472-1479 ◽  
Author(s):  
Gianluca D'Urso ◽  
Claudio Giardini
Keyword(s):  
Mechanical Properties ◽  
Process Parameters ◽  
Lap Joints ◽  
Cnc Machine ◽  
Friction Stir ◽  
Commercial Code ◽  
Welding Forces ◽  
Set Up ◽  
Deform 2D ◽  
Short Time

A study was carried out to evaluate how the Friction Stir Spot Welding (FSSW) process parameters affect the temperature distribution in the welding region, the welding forces and the mechanical properties of the joints. An experimental campaign was performed by means of a CNC machine tool and FSSW lap joints on both AA6060 and AA7050 aluminum alloy plates were obtained. Some thermocouples were inserted into the samples to measure the temperatures during FSSW. A set of tests was carried out by varying the process parameters, namely rotational speed, axial feed rate and plunging depth. Axial welding forces were measured during the execution of the experiments by means of a piezoelectric load cell. The mechanical properties of the joints were assessed by executing shear tests on the specimens. A comparison between the quality of the joints obtained on the two materials and a correlation between process parameters and joints properties was found. A FEM model for the simulation of the process was set up using the commercial code Deform 2D. The peculiarity of this model is a 2D approach used for the simulation of a 3D problem, in order to guarantee a very simple and practical model able to achieve results in a very short time. This solution was achieved, based on a specific external routine for the calculation of the developed thermal energy due to the friction between tool and workpiece. The collected experimental data were finally used to validate the model.

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