Non-destructive testing of pipings and vessels in power stations

By means of practice-oriented magnetite-filled cracks produced at laboratory scale, it was proved that by ultrasonic manual testing using commercial testing equipment such cracks were successfully detected. A comparison of the echo power of cracks with and without magnetite filling showed that a complete filling of the cracks with magnetite led to an average decrease of the echo power at the tested wall thicknesses of about 6 dB. The optimum failure detectability was obtained by 4 MHz miniature angular testing heads. For different component wall thicknesses and probable oblique cracks, further specimen measurements are necessary to determine the test system and the required test sensitivity. (orig.)