Calculation of the life of long steam turbine blades containing small cracks

Keywords

long steam turbine blade, small crack, crack tip opening displacement, residual life, corrosion-fatigue crack propagation.

Cite as

Andreikiv O. Ye., Dolinska I. Ya., and Skalskyi Т. V. Calculation of the life of long steam turbine blades containing small cracks. Physicochemical Mechanics of Materials. 2025. 61(6), 091-098.

https://doi.org/10.15407/pcmm2025.06.091

Abstract

A computational model to determine the residual life of a long steam turbine blade containing a short corrosion-fatigue defect (crack) is proposed. The blade is subjected to longitudinal tensile loading due to centrifugal force and cyclic bending in the plane of the disk. The computational model is formulated in terms of the crack tip opening displacement δ, which makes it possible to study microdefects in quasi-plastic materials. Based on available experimental data and the proposed analytical transformation, fatigue fracture kinetics diagrams for 20Kh13 steel are constructed in the da/dN ~ δ_t coordinate system. The residual life of a 20Kh13 steel blade is calculated. The influence of bending stresses caused by variable steam pressure at the nozzle exit, as well as the localization and initial size of the crack, on the residual life of the blade is evaluated.

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