Rotational Speed and Transducer Frequency as Factors Affecting Possibility to Detect Defects in Axisymmetric Elements with a Method of Eddy Currents

Abstract

The article describes the influence of two factors on the possibility to detect material defects in an axisymmetric element with a method of eddy currents. The factors the authors focused their analysis on include a rotational speed of the element tested, a frequency of the transducer, additional a placement of the measuring head (either on an inner or an outer surface of the test object). The investigations were carried out for a rotational speed n = 15; 30; 45; 60; 90; 120 rpm, and a transducer frequency f = 0.06; 0.1; 0.5; 1; 2 kHz. An SSEC III PC defectoscope was used for the control. The tests were performed on two bearing rings of different type. In both cases, artificially made surface or subsurface defects, in form of 1 mm blind holes, were analyzed. The authors conducted 120 measurements of the size of inner and surface defects altogether, and then classified larger and smaller distortions of the initial signal values as surface and subsurface defects respectively.