A brief introduction to non-destructive testing of ultrasonic sensors
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A brief introduction to non-destructive testing of ultrasonic sensors

Posted Date: 2024-01-29

A brief introduction to non-destructive testing:

NDT is the English abbreviation of non-destructive testing, which refers to a testing method that does not damage materials or workpieces, or does not affect their future performance or use. Types and functions of ultrasonic sensor non-destructive testing: By using NDT, defects can be found inside and on the surface of the material or workpiece, the geometric characteristics and dimensions of the workpiece can be measured, and the internal composition, structure, physical properties and status of the material or workpiece can be measured. wait. Commonly used non-destructive testing techniques include:

1. Radiographic flaw detection: Use the difference in intensity attenuation of X-rays or gamma rays when penetrating various parts of the object to detect defects in the object. If rays that are absorbed to varying degrees are projected onto X-ray film, after development, photos showing thickness changes and internal defects of the object can be obtained. If a fluorescent screen is used instead of film, the internal conditions of the object being inspected can be directly observed.

2. Ultrasonic testing: using the influence of the acoustic properties of the object itself or defects on the propagation of ultrasonic waves to detect defects or certain physical properties of the object. The commonly used ultrasonic frequency in ultrasonic testing is 0.5 to 5 megahertz (MHz). The most commonly used ultrasonic testing is pulse flaw detection.

3. Acoustic emission detection: Evaluate the performance or structural integrity of the material by receiving and analyzing the acoustic emission signal of the material. The phenomenon of stress waves generated by the rapid release of strain energy due to crack expansion, plastic deformation or phase change in materials is called acoustic emission. The acoustic emission produced by the ultrasonic sensor material under the action of external factors is received by the acoustic sensor and converted into an electrical signal, which is amplified and sent to the signal processor to measure various characteristic parameters of the acoustic emission signal.

4. Penetrant detection: Use the permeability of certain liquids to narrow gaps to detect surface defects. Commonly used penetrants are liquids containing colored dyes or fluorescent liquids.

5. Magnetic particle flaw detection: Ultrasonic sensors detect defects on the surface or near the surface of the object through the accumulation of magnetic particles in the leakage magnetic field near the object's defects. The object to be detected must be ferromagnetic. In addition, new non-destructive testing technologies such as neutron radiography, laser holography, ultrasonic holography, infrared detection, and microwave detection have also been developed and applied.

Review Editor: Huang Fei


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