Abstract
Abstract:
In ultrasonic defect sizing using the maximum echo amplitude technique,
the reflected echo signal height is taken to be related to the amount of ultrasound
propagated energy which is reflected from defects and to the information
contained in this reflected energy. In this investigation horizontal drilled holes of
known sizes are considered in grey cast iron which is usually treated as the most
difficult type of cast irons when ultrasonically inspected, due to its high sound
attenuated nature. The defects sizing results obtained from grey cast iron are
compared with those obtained from a steel of a similar pearlitic matrix structure as
a reference material. 2, 4, 6 & 8 mm drilled holes at known depths are prepared in
both grey cast iron and steel test samples. Maximum echo amplitude sizing
method is adopted, using both compression wave probes & shear wave probes of
1,2,4 & 6 MHz frequencies at different scanning positions. Although the results
are only limited to defect sizing in grey cast iron with reference to steel, they do
