Predicting long-term creep-rupture property of Inconel 740 and 740H

The prediction of long-term creep-rupture strength values for Inconel 740 and 740H is made at temperatures ranging from 650°C to 850°C by using Larson–Miller (LM) and Manson–Haferd (MH) methodologies. Then, the predicted creep-rupture strength values are compared with the ones reported by Wilshire–Scharning (WS) model, a new approach for life assessment. The results show that the LM method is easy to cause either underestimation or overestimation of long-term properties depending on the selected data. Compared with the LM and WS methods, predictions produced by MH method have a relatively good consistency with the experimental data over 30 000 h, and the 105 hours creep-rupture strength extrapolated from rupture life of 5000 h or more than 30 000 h are almost same. This suggests that the MH method is a better method for predicting the long-term creep-rupture strength of Inconel 740 and 740H alloys.