What is Ultrasonic Testing?

Ultrasonic testing is mainly used to detect buried defects in butt welds and cracks on the inner surface of pressure vessel welds. It is also used to detect possible cracks in Pressure Vessel Forgings and high-pressure bolts.

Ultrasonic testing can be divided into ultrasonic testing, ultrasonic thickness measurement, ultrasonic grain size measurement and stress measurement. There is a pulse reflection method to judge according to the echo of defects and the echo of bottom surface;

There are penetration method to judge the defect condition according to the shadow of the defect, and resonance method to judge the defect condition or plate thickness by generating standing wave from the tested object. At present, the most widely used method is pulse reflection method.

Characteristics of ultrasonic testing:

(1) The detection rate of area type defects is high, while the detection rate of volume type defects is low.

(2) It is suitable to inspect workpieces with thick thickness.

(3) Applicable to various test pieces, including butt weld, fillet weld, T-shaped weld, plate, pipe, bar, forging, composite material, etc.

(4) The inspection cost is low, the speed is fast, the detection instrument is small, light and convenient to use on site.

(5) The visual image of defects cannot be obtained, the positioning is difficult, and the quantitative accuracy is not high.

(6) There is no direct witness record for the inspection results.