Effects of the Microstructure and the Testing Conditions for the Detectability of the Small Flaw in Ultrasonic Testing

초음파시험의 미소결함탐지능에 영향을 미치는 미세조직과 시험조건의 영향

Effects of the microstructure and the testing conditions for the detectability of the small flaw in ultrasonic testing have been studied. The detectability of the flaw was influenced not only by the grain size but also by the microstructure of the test piece. This is considered to be caused by randomization of the matrix which influences the elastic anisotropy of the grain. It was found that the detectability was improved as the frequence became higher and the beam size became smaller. The experimental results indicate that ultrasonic backscattering measurement is one of the promising methods to evaluate the detectability of the flaw indirectly.