Detection device and method for distinguishing inner and outer wall defects based on electromagnetic detection signals

Abstract

The invention discloses a detection method for distinguishing inner and outer wall defects based on electromagnetic detection signals, comprising: step 1: placing the workpiece to be tested and the detection coil in an external local magnetic saturation environment; step 2: generating a certain frequency by a microprocessor square wave excitation signal, and amplify the power of the square wave excitation signal through the excitation amplifier circuit to excite the first detection coil and the second detection coil; step 3: form the first detection coil and the second detection coil in differential mode Constitute a differential electromagnetic sensor, load the square wave excitation signal after power amplification by the excitation amplifier circuit; step 4: pick up the signal of the differential electromagnetic sensor through the differential signal amplifier circuit, and perform adaptive amplification; step 5: use the integral processing circuit to The differentially amplified signal of the differential signal amplification circuit is rectified and integrated to determine the defect of the workpiece under test. The present invention is applied to differentiate inner wall / outer wall defects.

Description

technical field [0001] The invention belongs to the technical field of non-destructive detection of material defects, in particular to a detection device and method based on electromagnetic detection signals that can distinguish inner wall / outer wall defects. Background technique [0002] Eddy current testing is one of the methods of non-destructive testing in industry. The basic principle of eddy current testing is to place the coil with alternating current on the metal plate to be tested or put it outside the metal tube to be tested. At this time, an alternating magnetic field will be generated in and around the coil, which will cause a vortex-shaped induced alternating current in the workpiece to be measured, which is called eddy current. The distribution and size of the eddy current is not only related to the shape and size of the coil, the size and frequency of the alternating current, etc., but also depends on the conductivity, magnetic permeability, shape and size of ...

AI Technical Summary

Problems solved by technology

However, this invention requires unsaturated DC magnetization of the material. In actual detection, the magnetization current needs to be adjusted according to different detection objects, and because the inner / outer wall defects are distinguished by phase, the defect signal needs to be rotated to the required Phase, in the actual detection, need to adjust more parameters, not easy to use

Images