Application of a Modified Hyperbolic Sine Law for Modeling Minimum Creep Rate of 2.25Cr-1.6W

The creep damage and the need of modelling minimum creep rate is introduced, and recent research activities reviewed. To improve the accuracy and simplify the prediction of minimum creep rate, a modified hyperbolic sine law was chosen to model the minimum creep rate of 2.25Cr-1.6W with temperature from 773K to 923K and stress from 60MPa to 360MPa. The modified hyperbolic sine law was designed and used by this research group before with success. Here, the models for minimum creep strain rate were developed at constant temperature and/or multi-temperature. Very good accuracy was achieved for constant temperature cases, and compatible accuracy with existing literature was achieved for multi-temperature case studies. Furthermore, the model for constant temperature one was incorporated with Monkman-Grant approach for creep lifetime modelling, and very good accuracy was achieved. This paper, thus, contributes to the develop of methodology for accurately predicting minimum creep rate and lifetime, and the specific knowledge for the investigated low Cr steels. Concluded the future work would be exploring the potential of extrapolation by removing the lowest few stress loadings’ data points when optimizing constants.