Non-destructive method and device for ultrasonic testing of the material

Abstract

A process and a device for the nondestructive ultrasonic testing of the material of generator rotor teeth providing with an inserted slot wedge, using a probe arrangement including transmit probes, reference probes and defect detection probes which are disposed on a support plate in such a manner as to be movably attached to the teeth, wherein ultrasonic beams are transmitted and reflected by the rotor teeth flanks and the reflected beams are received in a reference probe utilizing a two-fold deflection of the sound at the tooth flanks which are inclined with respect to the tooth back. An ultrasonic beam, reflected by any existing defects of a given type and orientation, is selectively received outside the receiving range of the normally reflected acoustic beam by means of a defect detection probe, and the damaged locations is detected by comparison of the ultrasonic signals received by the reference and defect detection probes. Defects can be properly identified in rotor teeth having differing tooth flank angles by means of the two-fold beam deflection at the tooth flanks, and also with the use of additional reference probes.