Friction Stir Welding Lab

PROCESS DESCRIPTION
 
  FSW of 1018 St to 6061 Al
    Friction stir welding (FSW) is a solid-state joining process invented by TWI, UK in 1991. In this process:
  • A rotating tool is inserted in the material which traverses along the joint.
  • The rotary motion of the tool generates heat which creates a soft and plasticized region around the pin and the shoulders.
  • A durable weld is produced by extrusion and forging of the plasticized material from the leading side to the trailing side of the moving.
CURRENT INDUSTRIAL APPLICATIONS

  •  
     FSW Facilities in RCAM
    Automotive (Ford, Mazda, Audi, BMW, …) for engine and chassis cradles, wheel rims, truck bodies, fuel tanks, and motorcycle frames. 
  • Aerospace (NASA, Eclipse Aviation, Lockheed Martin, …) for wings, cryogenics fuel tanks for space vehicles, aviation fuel tanks, external throw away tanks in military applications.
  • Ship building and marine industries for welding panels in docks, sides and floors, helicopter landing platforms, and marine structures Railway industry for welding tankers and wagons.
 RCAM’s R&D ACTIVITIES
  • FSW of similar and dissimilar aluminum alloys (1xxx to 7xxx series).
 
 Hybrid manufacturing of complex parts
 
 
 Heat transfer simulation
  • FSW of dissimilar materials (Steel-Al, Cu-Al, Al-Ti, and other materials).
  • FSW in different joint designs (Butt, edge-butt, and Lap).
  • FSW in rapid manufacturing (e.g. abrasive water-jet cutting, FSW, and machining to produce complex products).
  • Designing and manufacturing of the FSW tools for wear-resistive applications using laser-based direct metal deposition (LBDMD ).
  • Weld microstructural analysis and mechanical tests.
  • Sensing and monitoring of the process using load cells, thermo-couples, and acoustic emission sensors.
  • Numerical simulations (material flow, structural, and heat transfer analysis).
SELECTED PUBLICATIONS
  • Chen, C. M., and Kovacevic, R., Joining of Al 6061 alloy to AISI 1018 steel by combined effects of fusion and solid state welding, International Journal of Machine Tools & Manufacture, Vol. 44(11), 2004, pp. 1205-1214.
  • Soundararajan, V., Atharifar, H., and Kovacevic, R., Monitoring and processing the acoustic emission signals from the friction-stir-welding process, Journal of Engineering Manufacture, Vol. 220(10), 2006, pp. 1673-1685.
  • Atharifar, H., Lin, D. and Kovacevic, R.,“Numerical Simulation and Experimental Investigations on the Loads Carried by the Tool During Friction Stir Welding”, the Journal of Materials Engineering and Performance, Vol. 18(4), June 2009, pp. 339-350.
  • Chen, C.M. and Kovacevic, R., “Parameteric Finite Element Analysis of Stress Evolution during Friction Stir Welding”, the Proceedings of the Institution of Mechanical Engineers, Part B, Journal of Engineering Manufacture, Vol. 220, (2006) pp. 1359-1371.


PROCESS DESCRIPTION
 
 Sequence of operations in FSSW
 
 Typical FSSW weld with developed tool
As a subsidiary process for FSW, friction stir spot welding (FSSW) is an alternative process to resistive spot welding (RSW) where the fusion of materials is replaced by solid-state joining. SMU-RCAM invented a new device for FSSW (see the patent app. below) characterized with the following functions:
•The FSSW welding head is placed above the area to be welded (position A). 
•Rotation of the tool is initiated, and the welding head is brought into contact with the workpiece (position B). 
•The tool with multiple pin is then pressed into the workpiece while the welding head is held in place (position C). 
•The tool is then retracted (position D), and finally the welding head is moved away from the workpiece (position E).
•RCAM’s invented welding head is capable to generate one weld-per-second.
 
 
   RCAM FSSW welding head         Multiple-pin tool
R&D AREAS
•FSSW of similar and dissimilar aluminum alloys (1xxx to 7xxx series)
•FSSW of dissimilar materials (Steel-Al, Cu-Al, Al-Ti, and other materials)
•Weld microstructural analysis and mechanical tests
•Sensing and monitoring of the process using load cells, temperature, and acoustic emission sensors
 •Numerical simulations (material flow, structural, and heat transfer analysis)
   
 Weld from conventional tool  Weld from multiple-pin tool
 
INDUSTRIAL APPLICATIONS
•Automotive (Ford, Mazda, Audi, BMW, …)
•Aerospace (NASA, Eclipse Aviation, …)
•Ship building and marine industries
•Railway industry
PUBLICATIONS
•Valant, M., Yarrapareddy, E., and Kovacevic, R., A novel tool design for friction stir spot welding, ASM 7th International Conference on Trends in Welding Research, Pine Mountain, GA., 2005.
•Valant, M., and Kovacevic, R., System and method for friction stir spot welding, US Patent Application No. 11/279,908, April 17, 2006.