METHOD OF DETECTING DEFECTS IN JOINTS BETWEEN POLYMER COATING AND METAL TUBES

摘要

FIELD: physics. ^ SUBSTANCE: ultrasonic pulses are transmitted to the coating using an ultrasonic flaw detector and PEP; the repeatedly reflected ultrasonic pulses are received and converted to echo signals; the position the PEP where the amplitude of the first echo signal is maximum is found; the amplitude of the first echo signal is set a given level; the depth-measuring device of the flaw detector is adjusted and the relationship between the amplitude of the first echo signal and the thickness of the coating is determined at standard parameters of adhesion of the coating to the metal on samples with different thickness of the coating; wherein the amplitude of the first half-period of the first echo signal is determined at samples with different thickness with different value of strength of the joint between the coating and the metal, standard, reduced by a known value, with a defective joint; a curve of amplitude of the first half-period of the first echo signal versus thickness of the coating for each value of the strength of the joint is plotted; the amplitude of the first half-period of the first echo signal and the thickness of the coating on the tube are determined and the strength of the joint is determined using the obtained relationships. ^ EFFECT: possibility of more reliable detection of defects of joints between a nonmetallic coating and metal tubes. ^ 3 cl, 2 dwg