Abstract
Delayed fracture tests with cathodically pre-charged specimens were performed measuring acoustic emission (AE). Experimental parameters were ratio of axial force to design bolt axial force, cathodically hydrogen charged time and effect of heat treatment. It was observed that time to fracture was somewhat affected by charged time and axial force ratio. Analytical process of diffusible hydrogen around a thread root and a tip of notch was compared with experimental one by AE signal and branching phenomenon near crack tip, and resulted in a good agreement.
