지식

Types of Equipment

For any ultrasonic gaging application, the choice of an optimum gage and transducer will be based on the type of test material, its thickness range, and the degree of measurement accuracy required. It is also necessary to consider part geometry, temperature, and any other special circumstances that may affect the test setup. Transducer selection is discussed in detail in Section 2 of this tutorial.

Commercial ultrasonic thickness gages are divided into two general types, corrosion gages and precision gages. Perhaps the single most important application for ultrasonic gaging is measuring the remaining wall thickness of metal pipes, tanks, structural parts, or pressure vessels that are subject to internal corrosion that cannot be detected from the outside. Corrosion gages are optimized for this type of measurement, and they use specialized dual-element transducers with separate transmitter and receiver elements angled towards each other to create a v-shaped sound path in the test material. Precision gages are generally use for all types of measurement other than corrosion survey, involving a wide variety of engineering materials and geometries. They use single-element transducers.

Within those two general categories, instruments range from simple to sophisticated. The simplest gages are small, hand-held devices that are optimized for specific applications using a limited number of transducers. More sophisticated instruments incorporate waveform displays to aid the operator in test setup and interpretation, as well as more advanced signal analysis software. Data logging capability and PC compatibility are universal among the better instruments currently available on the market.

continue on to
Theory of Operation >>