Patent ID: 8042399

Claim:
A method of inspecting a substantially circular circumferential weld for connecting an inner pipe to a coaxial outer pipe, either directly or else via a junction forging, inspection being performed by an ultrasound probe, the method comprising the steps of: using a robotic ultrasound probe comprising a plurality of multibeam piezoelectric emitter-receivers; a) positioning at least one said ultrasound probe inside said inner pipe, at a given position in the longitudinal axial direction of said inner pipe against the inside surface of the wall of said inner pipe, said given position facing or being close to said weld, so that the ultrasound beams from the various emitters in the axial plane of said inner pipe perpendicular to the plane of the bottom faces of said emitters cover at least the entire width of the weld in said longitudinal axial direction; b) causing the various ultrasound beams of the various emitters of said probe to scan while the probe is positioned in said given position; c) moving said probe in rotation about the longitudinal axis of said pipe through a given angle of rotation, and then d) repeating steps b) and c) until the entire circumference of said weld has been inspected; wherein the ultrasound beams from the various emitters are sent in said axial plane of the inner pipe in a plurality of different angles of inclination having different values relative to the plane of said bottom faces of said emitters so that in a single sequence of scanning the various beams, the various zones of said weld are inspected across its width; and wherein said emitters are arranged in three contiguous zones in the longitudinal axial direction, comprising: a first zone in which the emitters are offset in said longitudinal axial direction relative to said weld, and emit beams at a first angle of inclination towards said weld; a central second zone in register with at least the middle portion of the width of said weld, and in which said emitters emit beams at a second angle of inclination substantially perpendicular to the plane of said bottom faces of said emitters; and a third zone at the end of said central second zone opposite from the end at which said first zone is located, and likewise offset in said longitudinal axial direction relative to said weld and emitting beams at a third angle of inclination opposite to said first angle of inclination towards said weld.