Scanning defects in steel by a superminiature eddy current probe

Abstract

The article describes a hardware and software complex designed for nondestructive testing and study of material properties. When obtaining the results of studying conductive materials using a multi-frequency signal, a signal generation system has been developed, which generates both single- and multi-frequency signals suitable for computer-based frequency and amplitude control, as well as a signal receipt and analysis system capable of amplifying and filtering signals using bandpass filters and selective amplifiers. The system is running under software allowing the found defects to be visualized on graphs in real time. Sections of 08G2B high-strength steel pipes are scanned in the course of the research. The steel is ultra-low-carbon, which makes it possible to study its properties using the eddy current method. A special superminiature eddy current probe has been developed, which includes three coils: stabilizing, measuring, and exciting. The coils are placed on a pyramid-shaped core made of the 81NMA alloy. The voltage arrived at the measuring coil of the eddy current probe signal is used as a parameter containing information about the presence of defects in the object of control. Sections of pipes with model continuity defects - cracks and holes - are studied.