GE Ultrasonic USM Go, Руководство оператора

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USM Go Operator’s Manual xiii
Preface
Operator Training
The operation of an ultrasonic test device requires proper training in ultrasonic testing methods. Proper training comprises adequate
knowledge of:
•
The theory of sound propagation
•
The effects of sound velocity in the test material
•
The behavior of the sound waves at interfaces between different materials
•
The shape of the sound beam
•
The influence of sound attenuation in the test object and the influence of the surface quality of the test object
Lack of such knowledge could lead to false test results with unforeseeable consequences. You can contact GEIT or NDT societies or
organizations in your country (DGZfP in Germany; ASNT in the USA) for information on opportunities for training on ultrasonic
instruments that use time-of-flight measurements.
Accurate measurement results require a constant sound velocity in the test object. Steel test objects have only slight variations in sound
velocity, thus affecting only high precision measurements. Test objects made of other materials (e.g., nonferrous metals or plastics) may
have larger sound velocity variations, which could adversely affect the accuracy of the measurements.