VTT Industrial Systems
By: Mr Mika Sirén (VTT Industrial Systems)
Mika Sirén
VTT Industrial Systems
(Metallimiehenkuja 6, Espoo)
P O Box 1702
FIN-02044 VTT
Finland
Telephone: +358 9 456 1
Telefax: +358 9 460 627
E-mail: mika.siren@vtt.fi
Website: www.vtt.fi |
History
Established in 1942, VTT (Technical Research Centre of Finland) is today the largest research organisation in Northern Europe. VTT is an impartial, multi-disciplinary non-profit organisation carrying out research and development work, technology transfer and testing. With their more than 3000 employees, VTT's six research institutes provide annually more than 5000 domestic and foreign customers with a large variety of technology and applied research services.
One of the six institutes is VTT Industrial Systems with a turnover of 46 million 
and a staff around 550 people in three locations (Espoo, Tampere and Lappeenranta). The institute is divided into six research areas: Production Engineering; Product Performance; Reliability and Risk Management; Intelligent Products and Services; Production Systems; and Materials and Structural Integrity. The most important customer sectors are power generation, transport and mobile machinery industry, equipment manufacturing industry, ICT and electronics industry, and process industry.
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Fig.1. Arc-assisted laser welding of mild steel for marine applications
© 2002, VTT Industrial Systems |
Welding and joining research has a long and prosperous history at VTT. Apart from steels, aluminium has been one of the topics of welding research activities since the late 1970's. Main emphasis has been focused on manufacture and repair techniques for welded aluminium structures in transportation industries, mainly marine and rail applications.
In addition to fusion welding, extensive research work covers solid state bonding techniques for both conventional and advanced materials, including aluminium matrix composites and dissimilar joints with aluminium as one partner. In parallel with joining techniques, both destructive and non-destructive testing methods have been developed for the evaluation of joint integrity and mechanical properties of advanced and/or dissimilar material joints. Facilites for exhaustive static and dynamic testing as well as sophisticated analytical equipment for structural and metallurgical characterisation are also available at VTT Industrial Systems.
VTT's contributions to the EuroStir® project
- To conduct destructive and non-destructive testing on FSW joints
- To provide expertise and equipment for realisation of a real-time NDT system to HUT's FSW machine
- To model and simulate the residual stress state of FSW structures as well as their behaviour during and after welding
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Fig.2. Exploitation of penetration in terms of welding speed in mechanised GTA-welding of stainless steels
© 2002, VTT Industrial Systems |
VTT's plans for dissemination and exploitation of the EuroStir® know-how
VTT and HUT have worked closely for more than two years in order to introduce FSW in Finland at an industrial level. As a result of two past feasibility study projects, the first Finnish company begins with providing FSW job shop services in the summer 2002. Other FSW-related projects are also under consideration in Finnish industry. However, FSW industrialisation also requires supporting services for both developing appropriate welding procedures for a particular application, and for validating resulting joint properties and quality from both technical and economical viewpoints. This calls for contribution from research organisations. Together VTT and HUT have the infrastructure and facilities to develop knowledge to serve the Finnish FSW community by providing education and training on FSW, welding procedure and tool development work, as well as FSW related testing and analysis services.
Summary of services available at VTT Industrial Systems
VTT Industrial Systems offers a full range of both destructive and non-destructive testing facilities:
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Fig.3. Brazed Al-MMC to Al box for electronic packaging application
© 2002, VTT Industrial Systems |
- Static loading up to 2600 kN, dynamic loading up to 2000 kN
- Dynamic testing up to 300 Hz
- High temperature tensile testing up to 1000°C
- Uniaxial creep testing up to 1250°C, multiaxial creep testing up to 1000°C
- Surface inspection methods
- Radiography, both conventional and real-time
- Eddy current
- High frequency ultrasonic system for SAM (scanning acoustic microscopy)
- Phased array ultrasonic system planned for 2003
A great amount of experience has been gathered by the modelling group on various manufacturing processes, e.g. forming, extrusion, welding and casting. Together with state-of-the-art software tools and input from residual stress measurements at HUT this experience can be used to model and simulate the behaviour of FSW structures during and after welding.
Well equipped metallographic laboratories, e.g. optical microscopes, SEM's and FEGSTEM, are available for microstructural analysis with appropriate specimen preparation facilities and skilled personnel.
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Copyright © 2002, TWI Ltd