The development of advanced power plants demands alloys to operate at elevated temperatures and pressure for an extended period of time. Creep rupture data are often not available for higher operating conditions. Accurate extrapolation of creep life is necessary. One of the earliest and the most widely used life prediction model is the classic Larson-Miller Parametric (LMP) model. Over time numerous parametric models have been proposed. A recently proposed method is the parametric numerical isothermal datum (P-NID) approach that can be applied to an existing parametric model for reliable long-term extrapolation.  

In this study, the P-NID method is applied on LMP model to perform extrapolation for Inconel 617. Creep rupture data for five isotherms ranging from 800 to 1000◦C and stress levels from 9MPa to 170 MPa are used. Detail step by step procedure is provided for the application of P-NID method to calibrate LMP model (P-NID-LMP). A comparison of the extrapolation of the classic LMP and P-NID-LMP is provided. Normalized Mean Squared Error (NMSE) is used to analyze prediction accuracy. A 10% data-cull from the lowest stress data and 50% data-cull below 10% is performed to assess the reliability of extrapolation. It is observed that the P-NID-LMP provides more accurate extrapolation compared to the classic LMP model. Based on the comparison a recommendation is provided.


Extrapolation of Creep Rupture Data Using Parametric Numerical Isothermal Datum Method (P-Nid) for Inconel 617

Division / Sponsors: 
Pressure Vessels & Piping (PVP)


Paper Proceedings: https://asmedigitalcollection.asme.org/PVP/PVP2020/volume/83815

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