Fatigue crack growth behavior of JLF-1 steel including TIG weldments

The fatigue crack growth behavior of JLF-1 steel is very important for estimating life in terms of a critical crack length in a blanket. As a part of this work, the fatigue crack growth behavior of JLF-1 steel was examined in terms of the fatigue crack growth rate (da/dN) versus the stress intensity factor range (ΔK) curves. Test specimens consisted of full size compact tension (FCT) and half size compact tension (HCT) specimens of the base metal and TIG welded metal. The fatigue crack growth testing was carried out at constant amplitude cyclic loading under a stress ratio of 0.3 at RT and 673 K. From these results, the effects of TIG welding, test temperature and specimen size on fatigue crack growth behaviors are discussed within the Paris region. The fracture mechanisms of the fatigue crack growth test specimens were also analyzed using scanning electron microscopy (SEM).