Microstructural characteristics and low cycle fatigue properties at 230 ℃ of different weld zone materials from a 100 mm thick dissimilar weld of ultra-supercritical rotor steel

摘要

The low cycle fatigue properties at 230 degrees C and the microstructures of the material in different zones of 100-mm thick dissimilar joint made of ultra-supercritical rotor steels were studied. The microstructures, failure path and the fatigue fracture surfaces were characterized by scanning electron microscope and transmission electron microscopy. The relationship between strain level and fatigue life of 30Cr1Mo1V (BM-1), weld-seam (SAW) and 30Cr2Ni4MoV (BM-2) at 230 degrees C were obtained, respectively. The effects of microstructural characteristics on low cycle fatigue performance at 230 degrees C were discussed based on the morphology of dislocation cells in fatigued samples.