Statistical Thermal Fatigue-creep Modeling Of 316 Stainless Steel Material

The engineering structure and mechanical mostly experience high temperature and cyclic loading in petrochemical industry, power machine, aerospace power field, and so on. These complex load and bad working environment may change the equipment materials' fatigue and creep properties. It will have a considerable impact under the mutual action of fatigue and creep, and cause material damage cracks and constantly expand, finally happen ruptures, thereupon then lead to significant safety accidents in the end, cause large economic loss and people injuring. Whether these equipments can work safely in the use of residential period and we can predict their life accurately, may relate directly to life and property security. All these status will lead to economic loses and people casualty, cause huge economic damage and casualties, etc. At present in domestic and foreign many scholars and scientists are engaged in development and research of residual fatigue life at high temperature, and gain momentous achievements. Metal Materials under the environment of high temperature and cyclic loading, the mutual action of fatigue and creep will happen, but we can't prediction their life accurately. Both at home and abroad,316 stainless steel use widely in these industries field, So the paper choose 316 austenite stainless steel material as research object, will predict its life under high temperature and complex cyclic loading, and provide some reference to predict life accurately, under the mutual action of fatigue and creep for other metal materials.The aim of this thesis is to investigate the creep and fatigue behavior of 316 stainless steel. In the low cycle thermal fatigue life model, Manson's University Slopes equation was used as an empirical correlation which relates fatigue endurance to tensile properties. Fatigue test data was used in conjunction with different models to establish the relationship between temperature and other parameters. Then statistical creep models were created for stainless steel materials. In order to correlate the result of short-time elevated temperature tests with long-term service at more moderate temperatures,different creep prediction models, namely Manson-Hanford model, Sherby-Dorn model and Basquin model, were studied. Comparison between the different creep prediction models were carried out for a range of stress and temperature.A linear damage summation method was used to establish life model of stainless materials under fatigue creep interaction.Finally i establish the low cycle fatigue and high-temperature creep life prediction model,and give its prediction formula under different temperature and stress, so it can predict the life of 316 stainless steel under the mutual action of fatigue and creep, and provide theoretical references to predict high temperature and low cycle fatigue lifefor other similar materials under high temperature condition.