Evaluation of Computer Simulated Signals or Metallic Tabs for Standardizing Eddy Current Inspection Systems.

摘要

Nondestructive evaluation of tubing using the eddy current method normally requires standardization or calibration of the testing system against a set of known conditions or references (standards). This report presents the results of a study undertaken at Battelle-Northwest to investigate alternate means of calibration which might reduce the uncertainies experienced with the fabricated flaw method and improve the accuracy and reproducibility of eddy current inspection. Two approaches were selected for study: (1) The production of calibrating signals from specially prepared metallic-calibration tabs or passive coils translated past the eddy current inspection coil assembly. (2) The injection of electronically developed signals into the electromagnetic field surrounding the eddy current inspection probe which represent calibration or flaw responses.