Friction stir welding between extrusions and laminates

Abstract

Current market demands drive companies to innovate their production techniques to improve products and simultaneously hold down costs. In the search for solutions aimed at an optimization of production processes, semi-finished products in aluminium alloys very definitely play a significant role. Moreover, the assembly of extruded parts with laminates may result in considerable difficulties, especially in relation to distortions or generated residual stress and process productivity. A solution to these issues may be found in the application of friction stir welding (FSW), characterized by low thermal input and high productivity. The asymmetry of the FSW process determines a different thermal input to the edges of the pieces to be joined. This aspect can be exploited when it is necessary to join pieces characterized by a very different thermal lag, as occurs in the case of joining extruded products and sheeting. This study aims to identify optimal FW parameters, placing particular attention on heat transferred to materials so as to provide an adequate thermal input that will allow for compensation of the different thermal capacity of the pieces in question.

Keywords::

• Al–Mg–Si alloys
• aluminium alloys
• energy input
• friction stir welding
• hardness tests
• heat flow
• laminates
• mechanical properties
• mechanical tests
• metallography
• optimization
• process parameters
• tensile tests
• thermography

Notes

This paper was presented at the National Welding Days 6 workshop: ‘Joining Processes’, Genoa, 26–27 May 2011

Additional information

Notes on contributors

Enrico Lertora

Enrico LERTORA graduated in Mechanical Engineering in 2001 at the University of Genoa. He was also awarded a research doctorate in mechanical engineering at the same university. Since November 2008, he has been collaborating as a researcher at the Department for Production Engineering, Thermoenergetics and Mathematical Models at the University of Genoa, developing didactic activities and conducting research in the area of welding and structural bonding. In the field of welding he has been certified as an International Welding Engineer.

Carla Gambaro

Carla Gambaro was awarded a degree in Mechanical Engineering in 1980 at the University of Genoa. In 1981, she began to work in the Italian Navy division of the ‘Cantieri Navali Riuniti’ shipyards in Genoa, where she was involved in metallurgical aspects of the production of the wing system of submersed-wing hydrofoils. She has been working at the Department for Production Engineering, Thermoenergetics and Mathematical Models at the University of Genoa since 1 July 1983, developing both research and didactic activities (she is a tutor for General Technologies of Materials). In recent years, her research activities have been conducted in collaboration with international research institutes and companies operating in the field of innovative methodologies: friction stir welding and bonding.

Chiara Mandolfino

Chiara Mandolfino was awarded a degree in Mechanical Engineering in 2010 at the University of Genoa. In 2010, she received a research grant at the Department for Production Engineering, Thermoenergetics and Mathematical Models at the University of Genoa, where she has been involved in studies relating to non-conventional welding techniques and the evaluation of the influence of related processing parameters. Since January 2011, she has been working on her Research Doctorate in Mechanical Engineering at the University of Genoa, engaging in research activities within the area of innovative bonding technologies.

Matteo Pedemonte

Matteo Pedemonte was awarded a degree in Mechanical Engineering in 2009 at the University of Genoa. In 2009, he was granted a post as researcher at the Department for Production Engineering, Thermoenergetics and Mathematical Models at the University of Genoa, where he has been involved in studies on the choice of materials and the application of special processing technologies. Since January 2010, he has been working on a Research Doctorate in Mechanical Engineering at the University of Genoa, engaging in research activities within the area of automated bonding technologies.