Analysis of the Reasons for the Distortion of the Indicating Value of the Thickness Gauge

In the practical application of ultrasonic thickness measurement, especially in the monitoring of in-service equipment, if the indication is distorted and deviates from the actual thickness, the hidden danger of pipeline (equipment) will be caused, that is, the pipe fittings are replaced according to the wrong data, resulting in a large amount of material waste According to the tracking application of ultrasonic thickness measurement in recent years, the phenomenon and reason of indication distortion are analyzed as follows: 1 The reason analysis of no indication display or indication flicker instability: this phenomenon often occurs in field equipment and pipeline detection, after a large number of phenomena and data analysis, the reasons are summarized as follows: (1) the roughness of the workpiece surface is too large, resulting in poor coupling effect between the probe and the contact surface, low reflection echo, and even unable to receive the echo signal Most of the equipment and pipelines in service are rusted on the surface, and the coupling effect is very poor (2) the radius of curvature of the workpiece is too small, especially when measuring the thickness of small diameter pipe, because the surface of common probe is plane, the contact with the surface is