Low cycle fatigue behavior of electron beam welded joint of CLAM steel at room temperature

The low cycle fatigue (LCF) property of welded joint is a key issue of fusion reactor blanket safety. In this study, LCF behavior of China low activation martensitic (CLAM) steel joint welded by electron beam was investigated under different strain amplitudes. The experimental results showed that the LCF life of the welded joint was lower than that of the base metal. Both the base metal and the welded joints exhibited continuous cyclic softening. However, the welded joint revealed a lower cyclic peak stress compared to that of the base metal. The welded joint failed in the welded zone at the strain amplitude of 0.3% and failed in the base metal at the strain amplitudes of 0.5%, 0.7% and 1.0%, respectively. The welding inclusion or defect in the surface could be the source of fatigue crack and the fatigue crack propagated in welded metal and heat affected zone with a transgranular fracture mode.