Method for the non-destructive inspection of rotor blades of a steam turbine and inspection device for being used in said method

摘要

The invention relates to a method for the non-destructive inspection of rotor blades (Bn-1, Bn, Bn+1) of a steam turbine, said rotor blades (Bn-1, Bn, Bn+1) each being mounted on a rotor body by means of a pin root, whereby said pin root is received in a respective circumferential slot of said rotor body, and whereby said pin root is subdivided in radial direction into at least three root sections, the first of which is located outside of said rotor body, and the other ones having pin holes for fastening said pin root at said rotor body, said method comprising the steps of• providing a PA(Phased Array) probe with an ultrasonic PA(Phased Array) transducer (32) comprising a plurality of PA(Phased Array) elements, and being connected to a transceiver unit;• placing said PA probe on the surface of said first root section;• sending an ultrasonic beam in different directions into said pin root, whereby said beam direction is changed by using pre-selected ones of said plurality of PA elements and changing the phase relationship between said pre-selected PA elements;• receiving with said PA probe, echoes of said sent beams; and• analyzing said received echoes.;The inspection area within the root is improved by using a two-dimensional PA transducer (32), wherein a plurality of PA elements is arranged in a two-dimensional matrix configuration.