Principle of ultrasonic flaw detection of seamless steel pipe

Ultrasonic probes can realize the mutual conversion between electrical energy and sound energy, and the physical characteristics of ultrasonic waves when they propagate in elastic media are the basis of the principle of ultrasonic flaw detection for seamless pipes. When the directionally emitted ultrasonic beam encounters defects when propagating in the tube, it will produce wave reflection and wave attenuation. After the defect reflection wave is picked up by the probe, the flaw detector processes the defect echo signal and gives a quantitative Defect indication.

Ultrasonic flaw detection method for seamless steel pipe

The seamless steel pipe adopts the transverse wave reflection method to test under the relative movement of the probe and the steel pipe. During automatic or manual inspection, it should be ensured that the sound beam searches the entire surface of the seamless pipe. During automatic inspection, the two ends of the steel pipe will not be effectively inspected. This area is regarded as a blind area for automatic inspection. The manufacturing method can adopt effective methods to ensure the quality of this area.

When inspecting longitudinal defects, the sound beam propagates in the circumferential direction in the seamless steel tube wall; when inspecting transverse defects, the sound beam propagates in the tube wall along the tube axis direction. The inspection of longitudinal and transverse defects shall be carried out in two opposite directions of the steel pipe.

For automatic or manual inspection, a coupling medium that has good coupling effect and does not damage the surface of the steel pipe should be selected.