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

Claim 1

Method for the ultrasonic testing of the disc bodies, shrunk onto shafts; the disc bodies having shrink-fitted seats adjoining the shafts, a shrinkage influence zone adjoining the seats, hubs having inner surfaces adjoining the shafts, two-sided wheel discs adjoining the hubs, axial anti-rotation devices in the wheel discs, a rim of the wheel discs, and side walls of the wheel discs tapered radially outwardly from the hub to the wheel disc rim as seen in cross section, the axial anti-rotation devices having boundary surfaces with anti-rotation holes formed therein; which comprises: (a) ultrasonic angle beam probes operating according to a method of transversal wave reflection within a corner within the range of critical angles of total reflection, hereinafter referred to as corner reflection method, a grazing incidence method based on a grazing incident beam reflection principle, where both methods can be used as a pulse echo technique or as a tandem technique; (b) coupling the angle beam probes to the side walls for following tast patterns extending in circumferential direction of the disc bodies, aligning ultrasonic sound beams emanating from the angle beam probes towards the test regions of the inner surfaces of the hubs; (c) determining the presence of axially-radially oriented defects in the disc bodies with at least one of the corner reflection and grazing incidence method wherein in applying the corner reflection method a portion of an ultrasonic beam insonifying the boundary surface of the axial anti-rotation devices returns to a receiving angle beam probe only in the case of the total beam reflection within the corner formed by a boundary surface and a defect area and does not return in the absence of defects and wherein in applying the grazing incidence method the ultrasonic beam insonifying the boundary surfaces of the axial anti-rotation devices in a grazing manner creates a first hole echo in the absence of defects due to a 90° angle of incidence and creates a second echo in addition to the first echo having a substantially larger amplitude than the first echo in the presence of a defect due to an angle of incidence of substantially 90° at surfaces bordering the defect; (d) subdividing the inner surface of the hub into at least three axial test regions including a central test region and two adjoining outer test regions; (e) testing the outer test regions with the angle beam probes according to the pulse echo technique; and (f) testing the central test region according to the tandem technique with at least two of the angle beam probes, by transmitting with one of the angle beam probes on one of the side walls and receiving with another of the angle beam probes on the other side wall of the wheel discs.