A study on creep crack propagation behaviour of aged CrMoV for a long term used turbine

Article type: Research Article

Authors: Takeda, Hiroyoshi^; | Inukai, Takao

Affiliations: Haramachi Thermal Power Station, Tohoku Electric Power Co., Inc., Haramachi-shi 975-0021, Japan | Power and Industrial Systems R&D Center, Toshiba Corporation, Yokohama-shi 230-0045, Japan

Note: [] Corresponding author. E-mail: [email protected].

Abstract: 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 have 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.

Keywords: Aged CrMoV, creep damage, creep crack propagation

Journal: Strength, Fracture and Complexity, vol. 4, no. 2, pp. 93-101, 2006