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Method for Ultrasonic Inspection of Turbine Disc Rims

Abstract: 

Low pressure turbine disc rims are inspected by a method in which an ultrasonic beam is directed into a disc rim steeple from a location on the disc rim web. Reflected waves are received and signals indicative thereof are produced for display. A predetermined time window is established on the display, based on the time-of-flight difference between the top of the steeple and the disc rim. The presence of signals within the time window on the display is determined to indicate the presence of a crack. Cracks located along the steeple serrations and oriented in a generally tangential direction to the steeple cross section are detected by producing an ultrasonic beam directed along a line normal to the bottom of a steeple. Cracks located at the bottom of a blade groove at the steeple root and oriented in a generally radially direction can be detected by producing an ultrasonic beam skewed at an acute angle relative to the line normal to the bottom of a steeple.

Patent Number: 
4,502,331
Date Of Issue: 
03/05/1985
Inventors: 

Gurvinder P. Singh