ULTRASONIC BEAM CONTROL METHOD FOR ULTRASONIC FLAW DETECTION OF STEEL PIPE USING ARRAY TYPE PROBE

摘要

PURPOSE:To obtain uniform detection sensitivity across thickness of a steel pipe, by regulating the control timing of reception and transmission to a group of vibrators composing an array type probe based on the geometric and flaw detecting conditions of the steel pipe and the probe. CONSTITUTION:An arithmetic processing section 25 computes the transmission and reception timings based on the geometric layout and flaw detecting conditions of a steel pipe and an array type probe so that the angles of ultrasonic beams from vibrators are all equal when incident upon the surface of a steel pipe. The angle of deflection of ultrasonic beams from vibrators 1-3 are determined of the results of the computation and excitation timing of a pulser 21 is controlled with a transmission control section 23 to deflect the beams in the alpha1 direction. Signals received by the vibrators 1-3 are controlled with a reception control section 24 passing through a receiver 22 and added up with an addition processing section 26 to permit the extraction of an ultrasonic signal in the direction of the angle alpha1 of deflection. Other vibrators operate likewise. The results are shown on a display 28 with a display control section 27 as video of an ultrasonic-beam-scanned section.