Studies On Life Prediction Of Creep-fatigue Interaction At High Temperature

The components which are used in the industry of petrochemical, power machine, aerospace and nulear energy mostly work in the status of high temperature and pressure. These complex and severe rugged environment create the very great effect to the fatigue and creep performance of materials of equipment which are the great challenge in the work condition of high temperature. Whether the machines run steadily in the working duration and the service life was estimated exactly directly affect the manufacture, wealth and security of staff. For this reason, low-cycle fatigue test at the temperature of 693K,823K and 873K and fatigue test having hold time at the temperature of 823K and 873K both controlled by strain will be carryed on, basing on the material of 316L austenitic stainless steel.Generalize the law of fatigue, creep and interaction, and analyse the organization of the deformation band and appearance of fracture using scanning electronic microscope. Discuss the law of fatigue-creep, initiation of crack and fracture mechanism at microscopic view.From the result of low-cycle fatigue test without hold time, the formular of Manson-Coffin estimating fatigue life at the temperature of 693K, 823K and 873K can be obtained by the way of fitting data. And generalize the relation between temperature and fatigue life. Fatigue life:Remarkably drop in fatigued life with the temperature raise; great effect at the greatter loading level; Cycle stress softens more easily at low temperature and the greatter loading level.From the result of low-cycle fatigue test having hold time, creep damage which is more severe with the hold time increase can be discovered, and drop in fatigue life accordingly. In order to estimate the fatigue life affected by fatigue and creep damage, The article amends the formula of Manson-Coffin by means of adding the parameter of time, basing on the theorem of damage cumulation. And the formula of life...