Investment Casting Ultrasonic Inspection
Ultrasonic nondestructive testing, also known as ultrasonic NDT or UT for short, is a method of characterizing the thickness or internal structure of a test piece by using high-frequency sound waves. The frequencies or tones used for ultrasonic testing are many times higher than the limit of human hearing, with the most common range being 500 KHz to 20 MHz. The time interval between transmitted and reflected rays was recorded by a cathode ray oscilloscope. Any cracks or voids in the casting will cause reflections or some sound from the crack to appear as a point between two points representing the thickness of the casting. From the distance between these points, the crack depth on the surface of the casting can be easily calculated.
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