Mechanical Fatigue Testing of a TF-He-Inlet Prototype at Cryogenic Temperature

During the superconducting magnet program for ITER, various cryogenic components need to be tested verifying their design. In the past a Helium inlet of the TF coil was tested under fatigue in 2005 following ASME criteria for fatigue qualification. However, this very first prototype achieved only 80% of the projected fatigue cycles. Looking at the breaking region it was concluded that an annealing of the HAZ took place during the welding process leading to a weakening of the metal possibly due to a poorly controlled weld.