Application and Standard Error Analysis of the Parametric Methods for Predicting the Creep Life of Type 316LN SS

Abstract

To predict the creep-rupture life of type 316LN stainless steels which are major structural components of liquid metal reactors, a number of creep-rupture data were collected through literature survey and experimental data of KAERI. Using the data, the creep-rupture life was analyzed by means of the Larson-Miller, the Orr-Sherby-Dorn and the Manson-Haferd parametric methods. Polynomial equations for predicting the creep life were obtained. In order to analyze the acceptance and use of the parametric methods, standard error values were accurately investigated by statistical process of the creep data. As for the results, the three parametric methods are found to be favorable in predicting the creep life of type 316LN stainless steel. Each method did not generate a large error in the standard error of the estimate with variations of the temperatures, but the Orr-Sherby-Dorn and the Manson-Haferd methods showed a better agreement than the Larson-Miller one. Especially, at higher the 700oC, the Manson-Haferd method conformed well to the experimental data. The reason is because the Manson-Haferd method includes two constants of ta and Ta.