A Study on Evaluation of Creep Crack Initiation and Propagation Behaviour for Aged Turbine Materials
Details
The rotor and casing parts of steam turbines exposed high temperature and high stress for extensive periods are deteriorated by correlation between creep and fatigue. Microcrack initiates and coalesce with the main crack under creep condition. In order to apply to steam turbine components for creep crack propagation evaluation, the most suitable parameter must be selected for creep crack propagation evaluations of degrade CrMoV. Therefore, in this study, the experimental characteristics of the creep crack propagation behaviour has been investigated by both FEM analysis and creep burst test of cylinder model for the aged CrMoV rotor steel. As a result, comparisons of predicted the crack length to crack propagation time being used by parameter J* and Q* with experimental results show good agreement. In the study, though parameter K is too conservative, both parameters J* and Q* are available to predict of the creep crack propagation behaviour for aged CrMoV steel for practical use.
