Influencing factors of ultrasonic thickness indication distortion

Ultrasonic Thickness Gauges are widely used in engineering construction, petrochemical equipment, and machinery manufacturing. They mainly use the ultrasonic probe to generate piezoelectric effect to transmit and receive ultrasonic waves. Ultrasonic Thickness Gauges are often affected by some factors in the actual application process, resulting in large or small indications. According to Huang Shengqing's description in "Application of Ultrasonic Thickness Measurement Technology", there are the following factors: (1) There are impurities in the measured object detected by the Thickness Gauge (substances with different sound velocities). When the acoustic impedance of the impurity is not much different from the acoustic impedance of the measured object, the thickness measuring instrument indicates the wall thickness plus the thickness of the impurity; when the impurity When the acoustic impedance of the thickness measuring instrument is greater than that of the measured object, the displayed value of the thickness measuring instrument will appear thickening, such as high-density substances appearing in steel castings.