Effect of cyclic loading on elastic–plastic fracture resistance of PHT system piping material of PHWR

The objective of the paper is to study the effect of cyclic loading on the fracture resistance of the SA 333 Gr.6 carbon steel material of the primary heat transport (PHT) system piping of Indian pressurized heavy water reactors (PHWR). Tests have been carried out on compact tension specimens machined from the pipe used in the PHT system. The effect of load ratio, incremental plastic displacement and loading displacement rate on fracture resistance properties of the material has been studied. The cyclic fracture resistance curve has been compared with the monotonic fracture resistance curve and has been found to vary significantly. A negative load ratio with very low incremental plastic displacement between two consecutive loading cycles, significantly affects the fracture resistance of the material.