Ultrasonic Testing

Traditional Ultrasonic inspection uses high frequency sound energy to conduct examinations and perform measurements. Considerable information may be gathered during ultrasonic testing such as the presence of discontinuities, material or coating thickness. The detection and location of discontinuities is enabled by the interpretation of ultrasonic wave reflections generated by a transducer. These waves are introduced into a material and travel in a straight line and at a constant speed until they encounter a surface. The surface interface causes some of the wave energy to be reflected and the rest of it to be transmitted. The amount of reflected vs. transmitted energy is detected and provides information on the size of the reflector,& therefore the discontinuity encountered. Three basic ultrasonic techniques are commonly used:

1. Pulse-echo and through transmission

  1. Normal / Angle Beam– Normal beam testing uses a sound beam that is introduced at 90 degrees to the surface, while angle beam utilizes a beam that is introduced into the specimen at some angle other than 90 degrees. The choice between the two is made based on:
  1. Contact and Immersion– To get useful levels of sound energy into the material, the air between the transducer and the specimen must be removed .This is referred to as coupling. Two types of coupling are utilizied:

Some of the most common Ultrasonic applications are:

Info from ultrasonic inspection can be presented in a number of formats:

Some of the major advantages of ultrasonic testing are:

Major limitations of ultrasonic testing are: