Thermo-mechanical fatigue crack growth behaviour of STS 347 base and weld material

An exact evaluation of the characteristics of fatigue crack growth rate (FCGR) is very important for the life assessment of the cracked components in nuclear power plant piping system. Surge line is one of the components exposed to severe thermal and mechanical fatigue loads caused by the difference of temperatures and the cyclic internal pressure, respectively. There are no standard methods for the case of cyclic thermomechanical FCGR test. In some papers, authors have used their own method to measure the FCGR. In this study an efficient testing system has been developed to measure the FCGR under cyclic thermal and mechanical loads. Using the developed equipment, the FCGR tests were performed for the specimens of STS 347 weld and base material