��1. College of Mechanical Engineering, Sichuan University of Science and Engineering, Zigong 643000, Sichuan,China 2. Key Lab in Sichuan Colleges on Industry Process Equipments and Control Engineering, Sichuan University of Science and Engineering, Zigong 643000, Sichuan, China
Abstract��High strain extremely low cycle fatigue (ELCF) properties of pressure vessel steel 16MnR were studied according to the actual working conditions and anti��seismic safety design of pressure vessel. The fatigue tests were conducted under uniaxial tension��compression loading with total strain control. on MTS 809 servo��hydraulic material testing machine. The ELCF behaviors, such as cyclic stress response characteristics and relationship between cyclic stress and strain were investigated. The strain��life data from the axial tests were used to derive suitable Coffin��Manson parameters for the test material. The micrographs of scanning electron microscope (SEM) reveal that several cracks initiate at the surface of the specimen, which results in multiple fatigue sites in ELCF. Then the cracks propagate inward together till ultimate fracture.