Sensitivity of the Electromagnetic Acoustical Technique for Testing Railway Rails by the Mirror-Shadow Method

Abstract

A study of the sensitivity of the electromagnetic acoustical (EMA) technique for detecting manufacturing defects of railway rails by a mirror-shadow method (MSM) has been carried out. It has been found that the sensitivity of the MSM with the EMA technique using bulk shear ultrasonic waves is, in certain cases, considerably higher than the sensitivity of the traditional “wet” echo-pulse method or mirror-shadow method with the use of longitudinal waves. Therefore, in order to renovate or design new technical means of ultrasonic acceptance testing of rails in factories, it is advisable to use the mirror-shadow method of testing with bulk elastic shear waves polarized normally to the direction of rail rolling. This would make it possible to reduce the acceptance of intolerable internal flaws of manufacturing origin.