ULTRASONIC FLAW DETECTOR FOR SQUARE BILLET

摘要

PURPOSE:To obtain an ultrasonic flaw detector/for a square billet which can detect a defect detected by an angle probe detecting a flaw in a part under the skin, as a directional defect, even in the part under the skin on condition that it is the directional defect extending from the central part of the square billet to the part under the skin continuously, when all sections of the square billet are subjected to flaw detection by using a vertical probe and the angle probe jointly. CONSTITUTION:A plurality of vertical probes 2 and angle probes 3 are disposed on the four sides of a square billet 1 and transmission-reception circuits 4 are connected to the probes respectively. A gate circuit 5 sets a plurality of gates for a flaw detection echo being an output of the transmission-reception circuit 4, and judges the existence or non-existence of a defect. A circuit 6 for processing a directional defect in a central part judges from an output of the gate circuit 5 whether the defect in the central part is a directional defect or not. A circuit 9 for processing the directional defect in a part under the skin takes in gate circuit outputs of the angle probe 3 and the vertical probe 2 and judges whether/or not a defect detected outside the central part of the square billet 1 is the directional defect extending from the central part continuously.