Creep ductility and modified Monkman-Grant equation for Gr.92 by incorporating total strain

ABSTRACTABSTRACTA modified Monkman-Grant equation, which can provide a more accurate means of predicting creep rupture life than the standard Monkman-Grant formula, has been investigated for Gr.92 using creep data in the NIMS Creep Data Sheets at 550 to 750°C. The tr versus minimum creep rate ε˙min plot, which is called the Monkman-Grant relation, deviates downward at low stresses and long times. Better correlation of the tr with the ε˙min is obtained by the replacement of tr with (tr /εr), where εr is the total or rupture strain. The (tr /εr) is inversely proportional to the ε˙min over a wide range of stress, temperature and test duration, and the magnitude of data scattering is only a little bit even at low stresses and long times. The creep life of Gr.92 can be predicted by evaluating the ε˙min, together with the εr evaluated from the stress and or ε˙min dependence.KEYWORDS: Gr.92 steelmonkman-grant relationtime to ruptureminimum creep ratetotal strain Disclosure statementNo potential conflict of interest was reported by the author.