SENSOR FOR CRACK DEPTH MEASURING INSTRUMENT BY DIRECT CURRENT POTENTIAL DIFFERENCE METHOD

摘要

PROBLEM TO BE SOLVED: To improve the operability and to carry out accurate measurement with as little error as possible, in a sensor for a crack depth measuring instrument by a direct current potential difference method for, when a three- dimensional fatigue crack or the like is formed on an object to be inspected, nondestructively measuring its depth.;SOLUTION: This sensor is formed of a probe part 9 provided with a one- dimensional proximity terminal formed by arranging four terminals, that is, a pair of current input-output terminals 11 and a pair of potential difference measuring terminals 12 on one straight line on the tip end of a holding part 8. The probe part 9 is provided with marks for positioning 15, by which it can be confirmed that the one-dimensional proximity terminal is orthogonally straddling a crack and that the center between one-dimensional proximity terminals corresponds to the intermediate position of the crack length, and is installed with a light for illumination.;COPYRIGHT: (C)2000,JPO