Low cycle fatigue tests were conducted using 100A elbow specimens of STPT410 with local wall thinning. Local wall thinning was machined on the inside of elbow specimens in order to simulate erosion⁄corrosion metal loss. The local wall thinning areas were located at three different areas, called extrados, crown and intrados. The elbow specimens were subjected to cyclic in-plane bending under displacement control without internal pressure. The effects of eroded conditions, such as eroded ratio, eroded angle and position, on the low cycle fatigue behavior and fatigue life were discussed. Three-dimensional elasto-plastic analyses were also carried out using the finite element method, which could accurately predict the location of crack initiation and the crack growth direction. In addition, the safety margin of the eroded elbows against seismic loading was evaluated by comparing the fictitious stress of elbows and the design code against seismic loadings.
