Coke Drum Fatigue Properties Of Materials Under Complex Stress State Study

During the operation of equipments in the modern industry ,the interaction of fatigue-creep under complex condition is often the cause of the failure of equipments. For the other side, with the rapid development of science and technology ,the study like this is booming, and the subject is becoming an integrated subject including macro-mechanics, metal microstructure and so on.In this paper, the high-temperature low-cycle fatigue life and fatigue crack propagation life tests are carried on the cylindrical axial symmetry specimens having precrack or non-precrack with different types of notches of 16MnR steel in common use in the petrochemical industry contacting coke drum equipment, the stress/strain and the range of stress/strain of dangerous points are received through stress analysis of the specimens using finite element program under multi-axial stress state. At last, the equations of evaluating the high-temperature low-cycle fatigue life and the fatigue crack propagation life are found through using the least-square regression method.The study on high-temperature low-cycle fatigue life and fatigue crack propagation life under multi-axial stress state shows that the fatigue life and fatiguecrack propagation life can be characterized by the equivalent plastic strain range △εp,the equivalent creep strain range △εc and the equivalent strain range △ε, and don't exit notch dependency, non-notch-dependency equations being given in the paper.