Evaluation of Nondestructive Inspection Methods Applied to Milled Step-down Areas. Volume 2: Figures

摘要

Fatigue cracks were produced in 102 specimens. After cracking, these specimens were inspected nondestructively by means of eddy currents, ultrasonics, X-rays and penetrants. The specimens were successively exposed to corrosion and the inspections repeated. Specimens were then opened forcefully and the fatigue nuclei were measured visually from the fracture surface. All the data obtained by the various nondestructive inspections and the visual examination are presented in graphical form. It is found that eddy current inspection and both types of ultrasonic inspection and X-ray radiography inspection miss astonishingly long cracks both before and after corrosion, especially shallow cracks. With all types of inspection there exists a clear tendency to miss cracks under a certain threshold level of crack depth. Sensitivity and reliability of eddy current inspection. Both types of ultrasonic inspection, X-ray radiography and penetrant inspection are seen to decrease significantly due to exposure to corrosion.