NDT methods for revealing anomalies and defects in gas turbine blades

The amount of energy produced by gas turbines is increasing all over the wo rld. One important part in these gas turbines is the turbine blading. Impro ved blades and vanes are being introduced while the industry also uses the old generation of blade types. Applicable NDT methods are needed for all bl ade types. Many NDT methods can be applied in laboratory environment. This overview describes a variety of methods for blade inspection such as dye pe netrant, eddy current, radiography and ultrasonic methods. Some of these me thods are considered on the basis of the experience gained in measurements. One new UT method is described, easily transferable for practical inspecti ons on site. A wide-aperture VTT probe has been developed for the put-pose. With this special probe, different blade properties can be measured, such as coating thickness, detection and size of cracks, delaminations as well a s mechanical properties.