With the continuous emergence of new technology and the continuous renewal of testing equipment, ultrasonic testing technology is one of the fastest growing and most widely used methods in the current nondestructive testing technology, which plays a very important role in the nondestructive testing technology. In the process of testing, in addition to ultrasonic testing instruments, the probe that transmits and receives ultrasonic also plays a very important role. Therefore, the performance of the probe and the proper selection of the probe in the testing process will directly affect the accuracy and reliability of the testing results. The following focuses on the classification, function and selection principle of piezoelectric ultrasonic probe.
Due to the different shapes, materials, purposes and conditions of the tested workpiece, different types of probes should be used in ultrasonic flaw detection. Ultrasonic probes can be classified in different ways, generally as follows.
1) According to the wave type of the detected workpiece, it can be divided into longitudinal wave probe, transverse wave probe, plate wave (Lamb wave) probe, creeping wave probe and surface wave probe.
2) According to the direction of incident beam, it can be divided into straight probe and angle probe.
3) According to the coupling mode between the probe and the surface of the workpiece to be tested, it can be divided into contact probe and liquid immersion probe.
4) According to the material of piezoelectric wafer, the probe can be divided into ordinary piezoelectric wafer probe and composite piezoelectric wafer probe.
5) According to the number of piezoelectric chips in the probe, it can be divided into single crystal probe, double crystal probe and polycrystalline probe.
6) According to the focus of ultrasonic beam, it can be divided into focus probe and non focus probe.
7) According to the ultrasonic spectrum, it can be divided into wide-band and narrow-band probes.
8) According to the curvature of the workpiece, it can be divided into plane probe and curved probe.
9) Special probes. In addition to general probes, there are also some probes under special conditions and for special purposes.