METHOD FOR ULTRASONIC INSPECTION OF WELDED JOINTS OF SMALL-DIAMETRE PIPES Russian patent published in 2010 - IPC G01N29/26 

FIELD: physics.

SUBSTANCE: profile of the welded joint of a pipe is scanned with an ultrasonic beam using piezoelectric plates of an ultrasonic piezoelectric transducer made in form of semicircle. Echo signals are picked up. Data are processed in the computing unit of the transducer. Two-dimensional ultrasonic images are obtained on a display and the location of the defects in the welded joint is determined. Scanning is carried out via transverse-longitudinal displacement of the piezoelectric transducer on one side and another of the welded joint. The scanning pitch along the joint must not be greater than half the diametre of the piezoelectric plate of the ultrasonic piezoelectric transducer made in form of a semicircle. The speed of linear displacement of the piezoelectric transducer during scanning must not exceed 100 mm/s. When an echo signal appears from a possible defect, its maximum is determined and identification is carried out by picking up the useful signal on the background of false noise signals. Limiting values of characteristics of the defect are determined and compared with standard parametres. Scanning is continued without recording if the equivalent area of the defect does not exceed the control value, and characteristics of the defect are measured and recorded if its equivalent area equals or exceeds the standard value.

EFFECT: more reliable inspection of welded joints of small-diametre pipes.

15 dwg