Evaluation of Shot Peened Turbine Blade Behaviour

The shot peening process applied to steam turbine blades by power generation industry to improve the fatigue resistance of the components. Current life assessment models applied in typical low pressure steam turbine blade material – FV448 do not account for the effects of corrosion and droplet erosion on the shot peened surface. One of the key objectives of this project is to investigate the effects of corrosion and droplet erosion on the surface roughness and subsequent fatigue behaviour of shot peened and un-shot peened samples experimentally to further guide lifing assessments for these turbine blade components. Hence corrosion has reduced the efficacy of shot peening but for the conditions studied here a benefit over ground sample fatigue performance is still retained. Electropolishing rates indicated that shot peening processes that produce higher levels of work hardening (deeper surface depths) are more electrochemically active thus are more likely to exhibit faster corrosion.