Ultrasonic testing of seams

Claim 1

Method of testing the welding seam of pipes, comprising: providing coupler fluid for contacting the pipe through which ultrasonic energy can be applied to and received from the pipe; (i) directing plural beams of ultrasonic energy from lateral directions without longitudinal component towards the welding seam, each beam being at right angles in relation to the longitudinal extension of the seam entering the pipe at different but fixed lateral distances from the seam, and detecting the interaction of the beams energy with different portions of the seam to obtain signal representations of the interactions including representation of any longitudinal defect in the said portion of seams, the energy being coupled to and from the pipe outside of the seam proper; (ii) directing ultrasonic energy towards the edges of the seam detecting interaction of the energy with a portion of the edges to obtain signal representation of such interaction including representation of any defect in such portions; (iii) directing ultrasonic energy towards the seam from a longitudinal direction without transverse component and independently from step (1) and detecting from another longitudinal direction the interaction of the energy with a portion of the seam to obtain a signal representation of the interaction including representation of any transversely extending defect in the latter portion of the seam; repeating the steps (i), (ii), (iii) sequentially on progressing portions of the seam in longitudinal direction to sequentially test the entire seam; and processing the said signal representation as obtained pursuant to the steps (i), (ii), (iii) as repeated to obtain representation of the respective signal contour and of the transition times in each instance for identifying defects on the basis of correlated responses of sequential steps (i) and (iii).