Methods For Predicting Creep Life Of GH4169 Superalloy

Because of its excellent high-temperature performance,creep performance,and fatigue radiation resistance,GH4169 superalloy is often widely used in oil,power,aerospace and other sectors,under the action of high temperature hot end parts.With the rapid development of industrial,the temperature of equipment industrial environment is getting higher and higher.Long-term service of equipment in such an environment will lead to creep and shorten the service life of equipment.During the long service period,creep failure becomes an important factor restricting the integrity of components.Therefore,the prediction and study of creep is very important for the design of high temperature equipment.Therefore,in this paper,various creep models are studied in depth to solve the problem of creep life prediction,and it is concluded that the revised projection method is very accurate in predicting the creep life of GH4169 superalloy.In actual working environment,equipments and application of high temperature creep life usually long,generally for several years or decade,want to directly through the long time test for creep data is difficult,so many of the domestic and foreign scholars developed a variety of short time accelerated test data extrapolation is used to get the material in actual working environment for a long time creep properties of the method,including theta projection,in the 1980 s,the British R.W.E vans,put forward the method after being launched,the researchers widely recognized.Evans et al.Used this method to study the service life of power plant equipment and made a large number of studies on the prediction of equipment life.Molf used this method to predict creep parameters of 316 L stainless steel under service conditions.Kim used this method to study the creep properties of Harrisburg alloy.The above experiments were carried out by using the theta projection method under the condition of constant load.Generally,creep tests are based on tests under constant loads,which are different from each other.Therefore,the theta projection method is modified to make it suitable for conditions under constant loads,which is called the modified theta projection method.In this paper,the creep life curve of GH4169 is predicted by the modified theta projection method,and the creep life of this material is estimated.This paper mainly summarizes the types of creep life prediction models.Based on the modified ? projection methoed,the creep data of GH4169 superally material under different temperatures and stresses were obtained by short-term creep experiments at high temperature and high pressure,and the corresponding creep curves were drawn.The obtained experimental curves were fitted nonlinearly by using the modified projection method,and the creep equations related to temperature and stress were estsblished to verify the creep life curve of GH4169 superalloy.Compared with the modified projection method,the CDM model considers the actual internal microscopic damage mechanism of materials,so its prediction effect is more clear and accurate.This method mainly analyzes and studies the creep damage mechanism of materials under certain experimental conditions,then improves and optimizes the traditional CDM model,introduces new parameters,and proposes a new CDM model.Through numerical calculation,the results of the improved model are in good agreement with the experimental data,thus providing an effective way for the prediction of high temperature creep life of GH4169 superalloy.By a comprehensive comparison of the above two prediction methods,it can be found that the modified ? method has higher accuracy when extrapolating the long creep life.However,this method is based on the parameters extrapolation of the phenomeno logical model,which cannot reflect the real creep process of materials,so the selection of model parameters is often difficult to control.Method because it is from the physical mechanism CDM model reveals the essence of material creep behavior,if you can set up a variety of microstructure evolution in the process of creep parameters related to a quantitative relationship with the damage degree in the CDM model,it is easy to realize reasonable solving model parameters,and thus makes the method in engineering application to achieve high temperature creep life of precise metal members of powerful tool.