Search results for " Welding"
showing 10 items of 244 documents
Comparative analysis of bonding mechanism in solid state metal working processes
2016
The Piwnik and Plata pressure-time bonding criterion was applied to Friction Stir Welding, Linear Friction Welding, Porthole Extrusion and Roll Bonding. A neural network was set up, trained and used to predict the bonding occurrence starting from the main field variable distributions calculated through specific numerical models developed for each process. The analysis of the results permitted to predict the occurrence of solid bonding and to highlight differences and analogies between the processes in order to obtain sound solid welds.
Numerical simulation of linear fiction welding (LFW) processes
2011
Solid state welding processes are becoming increasingly important due to a large number of advantages related to joining ''unweldable'' materials and in particular light weight alloys. Linear friction welding (LFW) has been used successfully to bond non-axisymmetric components of a range of materials including titanium alloys, steels, aluminum alloys, nickel, copper, and also dissimilar material combinations. The technique is useful in the research of quality of the joints and in reducing costs of components and parts of the aeronautic and automotive industries.LFW involves parts to be welded through the relative reciprocating motion of two components under an axial force. In such process t…
On the Solid Bonding Phenomena in Linear Friction Welding and Accumulative Roll Bonding Processes: Numerical Simulation Insights
2015
Solid Bonding based welding processes allow to obtain defect free joints with low residual stress and low distortion. However, the engineering and optimization of solid bonding processes is difficult and requires a large number of time and cost consuming test trials. In this way, proper numerical models are essential tools permitting effective process design. The aim of this research was the comparison of the material process conditions during two different manufacturing processes taking advantage of the same metallurgical phenomenon, namely solid bonding. Linear Friction Welding, used to weld non-axisymmetric components and Accumulative Roll Bonding, used to increase the mechanical propert…
Solid state bonding in extrusion and FSW: process mechanics and analogies
2006
Abstract The solid state bonding occurring in extrusion and in friction stir welding (FSW) processes is investigated through FEM models previously developed and validated. In particular, for the AA6082-T6 aluminum alloys, the most relevant field variables have been monitored and compared, such as strain, strain rate, effective stress and pressure. The aim of the research is the development of an effective FSW bonding criterion.
A two steps Lagrangian–Eulerian numerical model for the simulation of explosive welding of three dissimilar materials joints
2021
Abstract Explosion welding (EXW) is a solid-state joining process used to produce lap joints out of metal plates of dissimilar materials. During the process, a controlled explosive detonation results in a pressure wave pushing one of the plates to be welded, called flyer, against the other with high velocity. The high pressure and temperature generated, because of the impact energy decaying into heat, create the conditions for solid bonding phenomenon to take place. Due to the complexity of experimental tests, numerical simulation is considered a fundamental design tool for the process. Different approaches are found in literature to simulate the process. In this paper, a dual step Lagrangi…
Friction stir welding of lap joints: Influence of process parameters on the metallurgical and mechanical properties
2009
Abstract Aluminum alloys are widely used in the aircraft industries even if such materials present lower ductility with respect to steels, anisotropy phenomena and, more important, they are often “difficult” to be welded or even “non-weldable”. In the last years the friction stir welding process (FSW) was proposed and applied in order to get good mechanical and technological performances of the joints. In this paper, an experimental and numerical investigation on the lap joining of AA2198-T4 aluminum alloy blanks by FSW is presented. In particular the joints strength and metallurgical properties are investigated by varying the joint configuration and the tool geometry and rotational speed. …
Dissimilar material lap joints by Friction Stir Welding of Steel and Titanium Sheets: Process Modeling
2013
In the paper a continuum based FEM model for Friction Stir Welding of different material lap joint made out of thin stainless steel and titanium sheets is proposed. The simulation campaign was made out using the 3D Lagrangian implicit code DEFORM{trade mark, serif} by means of a rigid-visco-plastic approach. The model, already set up and tuned for FSW process of similar materials and geometrical configurations takes into account the different mechanical and thermal behavior of the two materials and the microstructural evolution of the considered titanium alloy in the same joint. Additionally, it is able to predict temperature, phase, strain and strain rate distributions and evolution at the…
Friction stir welding of stainless steel thin sheets in lap configuration
2013
New research trends for Friction Stir Welding include the use of highly resistant materials as steels and titanium alloys. In the paper a continuum based FEM model for Friction Stir Welding of lap joint made out of thin stainless steel sheets is proposed, that is 3D Lagrangian implicit, coupled, rigid-viscoplastic. The model, whose potential has been analyzed though temperature distribution comparisons, is able to predict temperature, strain and strain rate distributions, with varying process variables. In this way the FEM model can be applied for effective process and tool design.
Friction Stir Welding of Magnesium Alloys under Different Process Parameters
2010
Experimental and numerical investigations have been performed in order to study the effect of welding parameters on properties of FSW-ed AZ31 magnesium alloy sheets. The results, presented in terms of tensile strength and numerical field variables distributions, allow to understand the behaviour of such material when FSW-ed using different rotational and welding speeds for a given tool geometry.
Dissimilar Al/steel Friction stir welding lap joints for automotive applications
2016
A widespread usage of aluminum alloys for the fabrication of car-body parts is conditional on the employment of appropriate welding methods, especially if dissimilar welding must be performed with automotive steel grades. Dissimilar welding of aluminum alloys and steel grades poses some issues concerning the formation of brittle intermetallic compounds, difference in physical and chemical properties of the parent metals, and poor wetting behavior of aluminum. Friction stir welding is considered to be a reasonable solution to obtain sound aluminum/steel joints. A study on the join quality of dissimilar lap joints of steel and aluminum alloy sheets after friction stir welding is proposed here…