Eddy current probes are used extensively in industry to detect material defects and discontinuities. However, their use in scanning turbocharger turbine wheels is limited as the probes available on the market are often impractical at scanning the complex geometry blades on these wheels. This paper reports on the development and capability of a bespoke, flexible, eddy current array probe, for use in scanning complex geometry turbine wheels. The sensor has been designed to detect defects that have an undesirable effect on durability in the turbine wheel. These defects are predominately located in the turbine wheel blades and they may be either sub-surface or surface contacting. The blades of the turbine wheels were scanned using the eddy current probe. Various parameters were recorded for each of the defects that were identified by eddy current inspection. Multiple complementary Non-Destructive Evaluation (NDE) methods have been utilised to validate, characterise and understand the recorded parameters of these defects. These methods included; Fluorescent Penetrant Inspection (FPI) and 3D X-ray Computed Tomography (3DXRCT). The eddy current probe was able to identify both artificial and naturally occurring defects in the blades of the turbine wheels. The complementary NDE methods validated the sub-surface detection capability of this flexible array. Further work is in progress to develop improvements in cast turbine wheels. This will be achieved by monitoring blade quality using the eddy current probe while undertaking various experiments to optimise the casting procedure.
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