Search results for "Welding"
showing 10 items of 317 documents
Experimental and Numerical Analysis of Microstructure Evolution during Linear Friction Welding of Ti6Al4V
2015
Abstract Linear Friction Welding (LFW) is a solid state welding process used to joint bulk components. In the paper, an experimental and numerical study on LFW of Ti6Al4V titanium alloy is presented. A laboratory designed LFW machine has been used to weld the specimens with different contact pressure and oscillation frequency. The joint microstructure has been experimentally observed with SEM and EDS. A dedicated numerical model, able to predict temperature, strain and strain rate distribution as well as the phase volume fraction evolution, has been utilized to predict the final microstructure in the welded parts. It was found that complete transformation of the alpha phase into beta phase …
Numerical modelling of the linear friction welding process
2010
Linear friction welding (LFW) is a solid-state joining process applied to non-axisymmetric components. LFW involves joining of materials through the relative reciprocating motion of two components under an axial force. In such process the heat source is given by the frictional forces work decaying into heat determining a local softening of the material and proper bonding conditions due to both the temperature increase and the local pressure of the two edges to be welded. In the present work the authors present a numerical model of the linear friction welding process of AISI 1045 parts. The numerical model allowed to highlight the process mechanics and the physical conditions which must be r…
Towards Tool Path Numerical Simulation in Modified Friction Stir Spot Welding Processes
2009
Spot welding can be considered a very common joining technique in automotive and transportation industries as it permits to obtain effective lap-joints with short process times and what is more it is easily developed through robots and automated systems. Recently the Friction Stir Spot Welding (FSSW) process has been proposed as a natural evolution of the already known Friction Stir Welding (FSW) process, allowing to obtain sound spot joints that do not suffer from the insurgence of typical welding defects due to the fusion of the base material. In the paper, a modified Friction Stir Spot Welding (FSSW) process, with a spiral circular movement given to the tool after the sinking stage, is p…
Comparison between FSW and bonded lap joints - A preliminary investigation
2017
Difficult to weld aluminium alloys can be effectively joined by different alternative processes. Friction Stir Welding (FSW), among the solid-state processes and adhesive bonding represent two very attractive techniques. They allow the production of highly resistant joints avoiding the formation of the typical fusion weld defects. The aim of this work is to identify, analyse and compare the mechanical properties of AA6016 aluminium alloy joints made out of 1 mm thick sheets. FSW lap joints were and epoxy bonded joints were produced. Using the FSW results as benchmark, the overlap required in the bonded joint was identified to ensure the same static strength. Once the geometric configuration…
Metallurgical Phenomena Modelling in Friction Stir Welding of Aluminium Alloys: Analytical vs. Neural Network Based Approaches
2008
In this paper, the metallurgical phenomena occurring in friction stir welding processes of AA6082-T6 and AA7075-T6 aluminum alloys are investigated. In particular, to predict the local values of the average grain size, either a simple analytical expression depending on a few material constants or a properly trained neural network is linked to the finite element model of the process. The utilized tools, which take as inputs the local values of strain, strain rate, and temperature, were developed starting from experimental data and numerical results.
FSW of Lap and T-Joints
2010
Even if in the last years several researches have studied the Friction Stir Welding (FSW) process, it should be observed that most of these studies are concerned with the butt joint and just a few of them extend to more complex geometries. It is worthy to notice that the acquired knowledge on FSW process of butt joints is not immediately extendable to lap and T-joints. The first observation is that in butt joints the surface to be welded is vertical, while in lap and T-joints it is horizontal and placed at the bottom of the top blank to be welded; in this way a major vertical component of the material flow is required to obtain sound joints. In the FSW of lap-joints four different geometric…
Friction Stir Welding Of AA6082-T6 Sheets: Numerical Analysis And Experimental Tests
2004
3D numerical simulation of the Friction Stir Welding process is developed with the aim to highlight the process mechanics in terms of metal flux and temperature, strain and strain rate distributions. The numerical results have been validated though a set of experimental tests.
Microstructural Changes Determining Joint Strength in Friction Stir Welding of Aluminium Alloys
2005
In the paper the results of a wide experimental activity on friction stir welding (FSW) of aluminum alloys are reported. In particular the butt joints of two different materials, namely AA1050-O and AA6082-T6 were considered. Grains dimensions and precipitates density were investigated both in the parent materials and after the welding processes. Furthermore post-welding heat treatments effects on the joint strength were studied.
On the field variables influence on bonding phenomena during FSW processes: experimental and numerical study
2013
Solid state bonding recurs in several manufacturing processes, as Friction Stir Welding (FSW), Linear Friction Welding (LFW), extrusion of hollow profiles and Accumulative Roll Bonding (ARB). The former processes are nowadays of particular industrial interest because of the specific advantages with respect to the classic welding technologies. In FSW the solid state bonding is obtained between an undeformed “cold” material, already placed in the advancing side of the joint, and the “hot” material flow incoming from the retreating side. Proper conditions of pressure, temperature, strain and strain rate are needed in order to get the final effective bonding. In the paper experimental tests on …