Search results for "Fusion welding"
showing 8 items of 18 documents
Improving friction stir welding of blanks of different thicknesses
2007
Friction stir welding (FSW) appears to be a promising process even in the welding of blanks of different thicknesses. Actually, such particular tailor welded blanks (TWBs) are usually characterized by a reduction in ductility due to the utilized fusion welding process. In this paper the authors, starting from a preliminary feasibility study, investigate the possibility to improve the mechanical performances of friction stir welded blanks of aluminum alloy with different thicknesses. Both experiments and a FE analyses are developed for a few case studies with different thickness ratios between the blanks. The numerical investigations are performed with the aim to highlight the material tempe…
Computer Aided Design of an Effective Fixture for FSW Processes of Titanium Alloys
2011
During the last years welded titanium components have been extensively applied in aeronautical and aerospace industries because of their high specific strength and corrosion resistance properties. Friction Stir Welding (FSW) is a solid state welding process, currently industrially utilized for difficult to be welded or “unweldable” aluminum and magnesium alloys, able to overcome the drawbacks of traditional fusion welding techniques. When titanium alloys are concerned, additional problems arise as the need for very high strength and high temperature resistant tools, gas shield protection and high stiffness machines. Additionally, the process is characterized by an elevated sensitivity to te…
Friction Stir Welding of 3D Industrial Parts: Joint Strength Analysis
2006
In the recent years Friction Stir Welding (FSW) has become an important joining technique since it allows to weld light weight alloys rather difficult to be welded or even “un-weldable” with the classic fusion welding operations. In the paper the authors present the application of the FSW process to the joining of 3D complex shapes typical of the industrial environment. In particular the research was aimed to highlight the joint mechanical strength at the varying of the 3D geometry of the welding line.Copyright © 2006 by ASME
Use of pure vanadium and niobium/copper inserts for laser welding of titanium to stainless steel
2020
Abstract Niobium and vanadium have high metallurgical compatibility with titanium and therefore can be used as inserts to avoid the accumulation of brittle intermetallic phases such as Fe2Ti during the fusion welding of titanium alloys with steels. In the present study, the continuous double pass welding of 1 mm thick Ti-6Al-4V alloy and 316 L stainless steel plates through several mm wide pure vanadium or niobium insert was studied. In case of a vanadium insert, a beam offset on the vanadium was found to produce cold crack formation in vanadium/316 L melted zones containing more than 40 wt.% V despite the absence of σ phase. Whereas a centered beam position and offset on the steel side pro…
Finite Element Studies On Friction Stir Welding Processes of Tailored Blanks
2008
Although friction stir welding (FSW) has been successfully used to join materials that are difficult-to-weld or unweldable by fusion welding methods, it is still in its early development stage and, therefore, its potential has not been fully exploited yet. FSW appears to be a very promising process for tailor-welded blanks to overcome the difficulties encountered in traditional fusion welding processes for obtaining a sound welding with good nugget integrity. In this paper the friction stir welding process for tailored blanks of aluminum alloy is investigated through a FEM developed by the authors. In particular FSW for sheets with different thicknesses is studied. For each setup a differen…
FEM based prediction of phase transformations during Friction Stir Welding of Ti6Al4V titanium alloy
2013
Abstract Friction Stir Welding (FSW) is a solid state welding process patented in 1991 by TWI; initially adopted to weld aluminum alloys, it is now being successfully used also for high resistant materials. Welding of titanium alloys by traditional fusion welding techniques presents several difficulties due to high material reactivity with oxygen, hydrogen, and nitrogen with consequent embrittlement of the joint. In this way FSW represents a cost effective and high quality solution. The final mechanical properties of the joints are strictly connected to the microstructural evolutions, in terms of phase change, occurring during the process. In the paper a 3D FEM model of the FSW welding proc…
Model-assisted ultrasonic calibration using intentionally embedded defects for in-process weld inspection
2021
Abstract Automated in-process Non-Destructive Testing (NDT) systems are rapidly gaining traction within the manufacturing industry as they reduce manufacturing time and costs. When considering calibration and verification of such systems, creating defects of known geometry and nature during the deposition of a weld can: (I) help examine the capability of the automated system to detect and characterise defects, (II) be used to form a database of signals associated with different defect types to train intelligent defect classification algorithms, and (III) act as a basis for in-process gain calibration during weld inspection at high temperatures, where the ultrasound beam can be skewed as a r…
Solid State Joining of Thin Hybrid Sandwiches Made of Steel and Polymer: a Feasibility Study
2020
Abstract The growing demand for more environmentally friendly vehicles has led to an increased use of light materials in the transportation industry with the aim to reduce structural weight, fuel consumption, and gas emissions, thereby boosting cost-effectiveness and recyclable properties. Complex multi-material steel-based components would allow to improve mechanical properties and minimize weight even further. In particular, new sandwich materials made by steel outer skins and a polymeric internal layer seems very promising for obtaining mechanical performance and lightness at the same time. Unfortunately, traditional welding techniques, like arc welding, laser welding, and resistance spo…