2020 Volume 58 Issue Supplement Pages 8s-13s
A new welding method called low-temperature linear friction welding has been developed for joining various kinds of materials such as aluminum alloys, steel and dissimilar materials. 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. When using this newly developed welding 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 A6061 alloys. For many other alloys, 100 % efficiency joints are easily obtained. As an example, for a medium carbon steel, welding without any transformation is also possible because the peak 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 temperature can be completely controlled. Therefore, the welding temperature is determined by controlling the applied pressure. A thin 2 mm thick plate can be welded using this method, and the welding is completed within several seconds.
