METHOD FOR TESTING A WORKPIECE USING ULTRASOUND

The invention relates to a method for testing a workpiece (2) using ultrasound in a curved region (6) of the surface (4) of said workpiece, having the following steps: (a) a plurality of ultrasonic signals (14a, b) are emitted from a plurality of transmitting positions (Pa-f) at different pivot angles (Sa, b) in a pivoting range (16a, b) with the aid of at least one ultrasonic transducer (10a-f) and are injected into the workpiece (2), (b) a corresponding ultrasonic echo signal (18a, b) is received for each ultrasonic signal (14a, b), and the amplitude of the ultrasonic echo (E) produced upon entering the workpiece (2) or on the rear wall of the workpiece (2) is determined, (c) the ultrasonic echoes (E) having amplitudes representing local maxima are determined for each transmitting position (Pa-f), (d1) if an individual ultrasonic echo (E) having an amplitude representing a local maximum was determined for a transmitting position (Pa-f) in step (c), the associated ultrasonic echo signal (18a, b) of said echo is selected, (d2) if a plurality of ultrasonic echoes (E) having an amplitude representing a local maximum were determined for a transmitting position (Pa-f) in step (c) or if this is predefined for a transmitting position (Pa-f), ultrasonic echo signals (18a, b) are selected if only an individual ultrasonic echo (E) having an amplitude representing a local maximum was determined for an adjacent transmitting position (Pa-f) in step (c) by selecting those ultrasonic echo signals (18a, b) which are in a particular angle range (24) around the corresponding pivot angle (Sa,b) of the ultrasonic echo signal (18a, b) having the maximum amplitude of the ultrasonic echo (E) of the adjacent transmitting position (Pa-f) and which have an ultrasonic echo (E) having a maximum amplitude, (e) at least the selected ultrasonic echo signals (18a, b) are evaluated. L'invention concerne un procédé de contrôle d'une pièce (2) au moyen d'ultrasons dans une zone incurvée (6) de sa surface (4), comprenant les étapes suivantes : (a) on émet une pluralité de signaux ultrasonores (14a, b) au moyen d'au moins un transducteur à ultrasons (10a-f) à partir d'une pluralité positions d'émission (Pa-f) avec différents angles de pivotement (Sa, b) se trouvant dans une zone de pivotement (16a, b) et on les injecte dans la pièce (2), (b) on reçoit pour chaque signal ultrasonore (14a, b) un signal d'écho ultrasonore (18a, b) correspondant et on détermine l'amplitude de l'écho ultrasonore