Validation of a high resolution x-ray technique within the PARENT program
Paper i proceeding, 2014
The PARENT Round Robin Test (RRT) comprises a study of the efficiency of different nondestructive
examination (NDE) techniques to detect and size stress corrosion (SCC) crack in Ni-base
material. This report describes an x-ray technique that has been used for detection and characterization
of these defects.
The x-ray source is a 450 kV x-ray machine and the detector is CCD-based with fiber optic lens
and glass fiber optic scintillation screen. The imaging area of the detector is only 27 x 27 mm but the
spatial resolution is very high. The un-sharpness in the image plane is measured to be less than 0.08
X-ray radiography is a volumetric method and to be able to detect cracks or parts of cracks the
orientation has to be reasonably parallel with the x-ray beams. Therefor each defect is radiographed in
series of projections. The projection angle is from -10° to +10°, with increments of 2°. To determine
the size or the depth of the cracks a method are developed which describes the depth as function of the
movement of the observed crack tip between the end positions in the series of exposures.