2010 年 36 巻 3 号 p. 153-159
H-IIB Launch Vehicle Test Flight (H-IIB TF1) was successfully launched on September 11, 2009 from the Tanegashima Space Center, with carrying the H-II Transfer Vehicle (HTV) Demonstration which transports supplies to the International Space Station (ISS). The H-IIB is an upgraded version of current H-IIA to meet the requirement of HTV launch, and one of the major items to be new developed is the 5.2m-daiametr first-stage tank. The enlargement of propellant tank diameter causes higher load with internal pressure, the state-of-art welding manufacturing technologies, friction stir welding, is adopted in order to increase the high reliability of the tank structure. This paper describes the results of development process of H-IIB tank by applying the friction stir welding to the axial and circumferential directions with the self-reacting tool called “bobbin tool” which eliminates the use of conventional backing metals.