Keynote Speakers


Low-temperature Linear Friction Welding of Metal and Alloys with 100% Joint Efficiency

Hidetoshi Fujii
Osaka University


A new welding method called low-temperature linear friction welding has been developed for joining various kinds of materials such as aluminum, aluminum alloys, copper alloys, titanium alloys and steel. For heat-treatable aluminum alloys such as the 6000 series alloys, an approximate 70% joint efficiency is generally obtained even when using friction stir welding, because the precipitates are coarsened or disappear due to the high welding temperature. For this new wielding method, the welding temperature can be uniquely controlled by changing the applied pressure. By decreasing the welding temperature, joints with a 100% joint efficiency were obtained even for the heat-treatable alloys such as the 6000 series alloys. For many other alloys, 100 % efficiency joins are easily obtained. For example, for a medium carbon steel, welding without any transformation is also possible because the welding temperature can be decreased to below the A1 point. It was revealed that the welding temperature is determined as the temperature at which the ultimate tensile strength of the interface material decreased below the applied pressure. When the temperature dependence of the material strength is already known, the welding temperate can be completely controlled. Therefore, the welding temperature is determined by regulating the applied pressure. A thin plate of 2mm can be welded using this method, and the welding is completed just within several seconds.


Prof. Hidetoshi FUJII, a Vice director and professor of the Joining and Welding Research Institute, Osaka University, obtained a Bachelor degree in 1988, a Master degree in 1990 and a Ph.D degree in 1993 from Waseda University. He belonged to the Department of Materials Science and Metallurgy, University of Cambridge, UK as a visiting scientist and research associate from 1993 to 1996. After he joined the Joining and Welding Research Institute, Osaka University in 1996, he has become a professor since 2010.
His research interests are various friction welding methods such as Friction Stir Welding, Rotary Welding and Linear Friction Welding, welding under microgravity and the development of various innovative welding methods such as AA-TIG (Advanced A-TIG) method, Ultrasonic wave TIG, Joule-Heat High-Load Solid Welding method.
He has published more than 350 journal papers and received many awards such as the Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology (2016), several Best Paper Awards from Science and Technology of Welding and Joining (Institute of Materials, Minerals and Mining, UK) (2014), Japan Welding Society (2015), Japan Light Metal Welding Association (2015).