Penetrameter sensitivity and crack detectability after degradation of the radiographic procedure

Technical Report · Thu Mar 01 04:00:00 EST 1979

OSTI ID:6375544

Foster, B E; McClung, R W; Davis, E V

In radiography, a penetrameter is used to indicate image quality. The type common in American industry is a thin shim with right-cylindrical holes drilled through it. The thickness of the shim and the diameters of the holes are fractional parts of the specimen thickness (e.g., 2%). The ASME Boiler and Pressure Vessel Code recently relaxed the required radiographic penetrameter sensitivity (shim thickness and hole diameter). There was concern that this relaxation in penetrameter requirements would lead to a loss in radiographic sensitivity and flaw detectability. Radiographic studies (using isotopes and x rays) on penetrameter and crack sensitivities were conducted on steel specimens with thicknesses of 19, 25, and 32 mm (3/4, 1, and 1 1/4 in.) to determine the significance of this loss (if any) of radiographic sensitivity and flaw detectability. These specimens contained cracks with depths ranging from 1.5 to 5 mm. The radiographic technique was intentionally degraded by increasing the distance between the x-ray film and specimen and by changing the angle of the incident radiation beam in increments from normal to 25/sup 0/ with the plane of the sample and the cracks. Good penetrameter sensitivity of less than 2% (exceeding the relaxed Code requirements) could be maintained, even after the severe degradation of the radiographic technique. These studies were conducted on readily available flat plate samples; therefore, it is recommended that similar studies be performed on samples of different shapes, such as piping and castings.

• Research Organization: Oak Ridge National Lab., TN (USA)
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 6375544
• Report Number(s): NUREG/CR-0593; ORNL/NUREG/TM-273
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420500* -- Engineering-- Materials Testing
CRACKS
DEFECTS
ELEMENTS
IMAGES
INDUSTRIAL RADIOGRAPHY
MATERIALS TESTING
METALS
NONDESTRUCTIVE TESTING
PERFORMANCE
PLATES
SENSITIVITY
TESTING