Temperature and stress-regime dependent primary-secondary-tertiary creep constitutive model

• Published in: Materials at high temperatures Vol. 32; no. 4; pp. 384 - 389
• Main Authors: Hosseini, E., Holdsworth, S. R., Mazza, E.
• Format: Journal Article
• Language: English
• Published: Leeds Taylor & Francis 01.07.2015; Taylor & Francis Ltd
• Subjects: 1CrMoV; Alloys; Chromium molybdenum vanadium steels; Constitutive relationships; Creep (materials); Creep constitutive modelling; Creep rupture strength; Deformation; Mathematical models; Minimum Commitment method; Rotors; Rupture; Steam turbines; Stress analysis; Stress-regime dependency; Stresses
• ISSN: 0960-3409; 1878-6413
• DOI: 10.1179/1878641314Y.0000000029

High temperature deformation analysis of components such as steam turbine rotors requires a knowledge of the material deformation response for a wide range of stresses and temperatures. Deformation analysis of steam turbine rotors deals with stresses ranging above the material proof strength (shortly after plant start-up) down to those responsible for very long rupture durations (for the steady running phase of operation) at various temperatures. This study describes the construction of a temperature and stress-regime dependent (primary-secondary-tertiary) creep constitutive model to provide a more reliable representation for the material deformation response over wide ranges of stresses and temperatures. The adopted equation set is a refinement of the 'Characteristic Strain' model and depends in its formulation mainly upon creep rupture data. Successful application of the model for a 1CrMoV steel for a wide range of stresses over the temperature range of 450-675°C is demonstrated.