ETD are pleased to announce the successful recent completion of an NDT project using our Electrical Discharge Sampling Equipment (EDSE).
EDSE is a unique tool for NDT sample cutting, developed through R&D work involving ETD and one of our international partners. Its spark erosion cutting technique leaves behind no stress concentrations and rounded edges that do not require repair. EDSE is one of a groundbreaking range of NDT and engineering consultancy services offered by ETD.
In the most recent project, the EDSE was used successfully to remove two axial samples from the interstage gland area of a Steam Turbine (ST) rotor, where 2 off ‘boat samples’ were taken on the LP rotor between the stage 3 and 4 rotor discs. ETD mounted the EDSE cutting head in the confined space between the rotor discs using a magnetic mounting system and bespoke frame. The rotor itself was from a double-flow Low Pressure (LP) type ST with 5 stages.
The boat samples taken both measured 12mm in depth (thickness), 20mm width and were approx. 80mm in length. The material of interest was removed, since it contained small surface defects which had been detected by NDT – in need of root cause analysis to pin point the cause of material degradation.
Following this work, the rotor is to be machined in order to dress-out and remove the excavation sites (by diametric reduction of the interstage gland area) as part of the component refurbishment cycle, before the expected return to service of the rotor.
The EDSE is available for purchase or rental, or for use as part of ETD’s services .
For more information on the Electrical Discharge Sampling Equipment click here.