Method for the ultrasonic testing of discs shrink-fitted onto shafts in vicinity of shrink-fitted seats, and apparatus for carrying out the method

摘要

A method for the ultrasonic testing of disc bodies, shrunk onto shafts, is especially adapted for testing the shrink-fitted seats thereof adjoining the shafts and usually is provided with anti-rotation holes containing anti-rotation inserts. Such disc body arrangements are often used in the field of low pressure turbine rotor disc fastenings. The method is carried out by using ultrasonic angle beam probes operating according to a method of corner reflection or transversal waves within the range of critical angles of total reflection, or according to a method of grazing incidence. Both methods can be used as a pulse echo technique, or as a tandem technique. The probes are coupled to the curved side walls of the discs for following test patterns extending in circumferential direction of the disc bodies. Ultrasonic sound beams emanating from the probes are aligned toward the test regions of the inner surfaces of the hubs. Three axially adjacent test regions are tested. The outer regions are tested with the angle beam probes according to the principle of the pulse echo technique, whereas the central test region is tested according to the principle of the tandem technique with at least two of the angle beam probes, by transmitting with one of the probes on one of the side walls and receiving with another one of the probes on the opposite side wall of the wheel discs. The invention also relates to an apparatus for carrying out the method.